HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology j (■ V f I •> \ I I / I 1 'j JhcWilsonBulktin PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W. VA. VOL. 82 No. 1 MARCH 1970 PAGES 1-112 The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President-William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. First Vice-President— Pershing B. Hofslund, Dept, of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812. Second Vice-President— Kenneth C. Parkes, Carnegie Museum, Pittsburgh, Pennsylvania 15213. Secretary — Jeff Swinebroad, 8728 Oxwell Lane, Laurel, Maryland 20810. Treasurer — William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. Elected Council Members — Andrew J. Berger (term expires 1970) ; C. Chandler Ross (term expires 1971); Ernest P. Edwards (term expires 1972). Membership dues per calendar year are: Sustaining, $10.00; Active, $5.00. Life memberships, $150 (payable in four installments). The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new books; members and friends are invited to maintain the fund by regular contribution, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 104 periodicals as gifts and in exchange for The Wilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer (small sums in stamps are acceptable). A complete index of the Library’s holdings was printed in the September 1952 issue of The Wilson Bulletin and newly acquired books are listed periodically. The Wilson Bulletin The official organ of the Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Morgantown, West Virginia, The subscription price, both in the United States and elsewhere, is $6.00 per year. Single copies, $1.50. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at S1.50 each) and may be ordered from the Treasurer. Special prices will be quoted for quantity orders. publications, books and publications for reviews should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, Michigan. Second class postage at Lawrence, Kansas, U.S.A. 66044 Allen Press, Inc., Lawrence, Kansas 66044 THE WILSON BULLETIN A Quarterly Magazine of Ornithology George A. Hall Editor Editorial Advisory Board William C. Dilger Andrew J. Douglas A. James Robert W. William A. Lunk Kenneth C Glen E. Woolfenden Ornithological Literature Editor Olin Sewall Pettingill, Jr. Volume 82 1970 Meyerriecks Nero . Parkes Published by THE WILSON ORNITHOLOGICAL SOCIETY vn/iiiGu THE WILSON BULLETIN A QUARTERLY MAGAZINE OE ORNITHOLOGY Published by The Wilson Ornithological Society VoL. 82, No. 1 March 1970 Pages 1-112 CONTENTS Ross’ Geese (Chen Rossii) Nesting on an Island at Karrak Lake, Northwest Territories, 24 June 1967, Photograph by John P. Ryder . Facing Page 5 A Possible Factor in the Evolution of Clutch Size in Ross’ Goose John P. Ryder 5 OoLOGicAL Data on Egg and Breeding Characteristics of Brown Pelicans Daniel W. Anderson and Joseph J . Hickey 14 Niche Overlap in Feeding Assemblages of New Guinea Birds John Terborgh and Jared M. Diamond 29 An Appraisal of the Song of the Black-Capped Chickadee Keith L. Dixon and Raymond A. Stejanski 53 Status and Speciation in the Mexican Duck (Anas diazi] John W . Aldrich and Kenard P. Baer 63 Parasitism by the Brown-headed Cowbird on a Brown Thrasher and a Catbird Robert M. Mengel and Marion Anne Jenkinson 74 High Density of Birds Breeding in a Modified Deciduous Forest David W . Johnston 79 Indexing Population Densities of the Cardinal with Tape- Recorded Song Douglas D. Doiv 83 General Notes ON THE VALIDITY OF SOME SUPPOSED “FIRST STATE RECORDS” FROM YUCATAN Kenneth C. Parkes 92 HIGH DENSITY MALLARD NESTING ON A SOUTH DAKOTA ISLAND Rod C. Drewien and Larry F. Fredrickson 95 COURTSHIP DISPLAY OBSERVED BETWEEN TWO SPECIES OF BUTEOS Brace. R. W othuter and Frank Kish 96 FOOD HABITS OF WINTERING SPARROW HAWKS IN COSTA RICA Rot>erl E. Jenkins 97 MARSH HAWK CHASES CROWS MOBBING OWL IFil/iani E. Southern 98 RUDDY TURNSTONES MAKING USE OF YELLOW-CROWNED NIGHT HERONS FOR FOOD- FINDING Haverschmidt 99 COMMON TERNS PIRATING FISH ON GREAT GULL ISLAND Helen HuyS 99 SAND-KICKING CAMOUFLAGES YOUNG BLACK SKIMMERS Helen Hays and Grace Donaldson 100 BARN OWLS HUNTING BY DAYLIGHT IN SURINAM F- Haverschmult 101 FOOD PREFERENCES OF A HAND-RAISED BLUE JAY A. R. W elsbrod 101 A WHITE-THROATED SPARROW NEST IN WESTERN PENNSYLVANIA Ted GrlsCZ 102 Ornithological News 104 Ornithological Literature 105 Joseph J. Hickey (Ed.), Peregrine Falcon Populations, reviewed by David B. Peakall; Burt L. Monroe, Jr., A Distributional Survey of the Birds oj Honduras, reviewed liy Eugene Eisenmann; Edgar M. Reilly, Jr., The Audu- bon Illustrated Handbook oj American Birds, reviewed by Mary Heimer- dinger Clench; Kurt M. Bauer and Urs N. Glutz von Blotzheim, Handbuch der Vogel Mitteleuropas, reviewed liy Sam E. Weeks. 71 739X C 70 > ;cr ROSS' GEESE (Chen rossii) nesting on an island at Karrak Lake, Northwest Terri- tories, 24 June 1967. Note males standing, females incubating and the paucity of vegetation within the nest territory. A POSSIBLE FACTOR IN THE EVOLUTION OF CLUTCH SIZE IN ROSS’ GOOSE John P. Ryder About 25 years ago David Lack advanced the theory that clutch size, in birds which feed their young, has evolved in relation to the size of the brood producing the greatest number of young that reach sexual maturity, the ultimate limiting factor being the availability of food required by the young (Lack, 1954, 1966a). According to another major viewpoint ( Wynne-Edwards, 1955, 1962), clutch size has evolved in relation to, and compensates for, the average mortality of a population. This idea, based primarily on the theory of “intergroup” selection, says that clutch size increases in a depleted (low density) population and decreases as the popu- lation density increases. Wynne-Edwards (1962) gives many examples of this “density-fecundity” relationship in most animal groups. The ultimate limiting factor in his proposal is food, whereas the proximate limiting factor is the regulation of population density by social behavior. Arguments for and against both theories are now in the literature (Brown, 1964; Cody, 1966; Lack, 1954, 1965, 1966a; Perrins, 1964; Skutch, 1967; Smith, 1964; Wiens, 1966; Wynne-Edwards, 1955, 1962, 1963). Eew ideas have been published on the limitations or on the significance of clutch size in birds which do not feed their young, for example the family Anatidae (ducks, geese, and swans). The purpose of this paper is to suggest that the clutch size of Ross’ Goose [Chen rossii) , a nearctic anserine, has evolved in relation to the food reserves which the female accumulates before arriving on the breeding grounds. I suggest that an important factor in the evolution of the clutch size is the number and size of eggs which provide enough food reserves for the newly hatched young until they are able to feed themselves (see Kear, 1965), and which also leave enough for the female to give maximum attentiveness to the eggs during incubation. The amount of food the female stores is limited by the total increase in body weight she can carry during the spring migra- tion and maintain long periods of flight. Lack (19666) published one of the first suggestions concerning the sig- nificance of clutch size in waterfowl. He states that the average clutch size for each species has been evolved in relation to both the average availability of food for the female at the time and place of egg laying, modified by the relative size of the egg. He expresses essentially the same idea in a recent, more detailed review of waterfowl clutch sizes (Lack, 1968). My hypothesis Frontispiece: The larger l)irds are Lesser Snow Geese [Chen hyperhorea) . 5 6 THE WILSON BULLETIN 1970 Vi)l. 82. N 0.05, Table 1). There remains tlie possibility that some egg collectors sought larger clutches. Calculations and Indices. — All data were analyzed with an IBM 1620 computer. Sta- tistical analyses followed Steel and Torrie (1%0). A size index for eggs was calculated by multiplying length by breadth and was used as a crude index to volume. In a study of White Pelicans (P. erythrorhynchos) (D. W. Anderson and J. J. Hickey, unpublished), we have found displaced volume to be correlated with this size index iP < 0.001). Geographical variations in egg size, shell thickness, shell weight, clutch size, and egg dates were determined in a stepwise manner as follows: (1) current snljspecific range boundaries were determined from the AOU Check-list (1957) and Palmer (1962:275), and the range was then subdivided into small geographic units such as a single state; (2) the eggshell data for these were then tested for significant differences and regrouped until a region was obtained containing a maximum number of subunits that were not significantly different from each other; (3) groupings never included more than one 16 THE WILSON BULLETIN Marcii 1970 Vol. 82, No. 1 Table 2 Geographical Variation in Eggshells of North American Brown Pelicans, 1879 TO 19431 Subspecies Area occ West Indies car S.C. car Fla., Ga. car La. car Panama car Texas cal Baja Calif. cal So. Calif. Number 6 43 208 42 7 115 174 85 Wt. fg) 8.05 9.46 9.78 9.87 9.94 10.00 10.99 10.59 ±95% C.L. ±0.90 ±0.35 ±0.12 ±0.32 ±0.49 ±0.26 ±0.18 ±0.24 Size Index (cm-) 33.2 37.6 37.6 38.2 37.4 38.5 40.0 39.0 ±95% C.L. ±0.6 ±0.9 ±0.3 ±0.7 ±1.0 ±0.6 ±0.4 ±0.7 No. Subelliptica] 3 21 109 20 2 52 94 44 No. Oval 3 22 99 22 5 63 80 41 Thickness Index- 2.42 2.52 2.60 2.58 2.66 2.59 2.74 2.71 ±95% C.L. ±0.24 ±0.06 ±0.02 ±0.06 ±0.10 ±0.04 ±0.02 ±0.04 Number 6 23 172 24 — 43 83 28 Thickness (mm) 0.510 0.557 0.557 0.554 — 0.557 0.569 0.579 ±95% C.L. ±0.031 ±0.021 ±0.004 ±0.014 — ±0.012 ±0.008 ±0.014 1 The pre-1943 means that were not significantly different at the 95% level in Duncan’s New Multiple Range Test (Steel and Torrie, 1960:107—109, 114) are underscored. 2 From Ratcliffe (1967): Thickness index = 10 X wt. in g/( length X breadth in cm). described subspecies; and (4) phenological subdivisions were kept at the smaller units without regrouping. RESULTS AND DISCUSSION Geographical Variation in Egg Parameters. — Egg-size index, shell weight, and shell thickness (Table 2) tended to vary with the size of the bird as discussed by Romanoff and Romanoff (1949:150). Our index to body size was obtained by using two common standard measurements that tend to measure skeletal size (tarsus and culmen) (Eig. 1). These skeletal measure- ments were taken from Wetmore (1945) and represent those of female birds. Wetmore (1945) ranked the size of the three North American subspecies, from largest to smallest as follows: P. o. calif ornicus, P. o. caroUnensis. and P. o. occidentalis. The general shape categories (Table 2) were, nonetheless, not significantly different iP > 0.05, Chi-square test) from area to area or between sub- species. Ordinary shape changes in the eggs of domestic poultry have already been shown to have little effect on the shell present as a percentage of total egg weight (Asmundson and Baker, 1940). Of the subspecies caroUnensis, birds from Texas tended to have the largest Antlorson and Hickey BROWN PELICAN EGG AND BREEDING DATA 17 40 - X 38 - UJ Q Z UJ 3 6 N cn o o 34 UJ 32 - P. 0. californicus P. 0. carolinensis ►SIZE >WT. P. 0. occldentalis 20 22 (TARSUS X CULMEN )/ 1000 24 10 UJ X (/) CO 5 S CL C5 8 Fig. 1. Relationship between two egg measurements and index to body size in three sulrspecies of Brown Pelicans. The index to body size was calculated in mm“ units and is shown on the abscissa. Eggshell size was taken as the product of length and breadth in cm'-. eggs. Louisiana eggs tended to be intermediate between those from Texas and those from areas to the east (Table 2). South Carolina birds tended to have smaller and lighter-shelled eggs than birds from farther south in Elorida and Georgia, although not significantly so (Table 2). The Baja California eggs iP. o. californicus) were represented mostly by specimens from Los Coronados Island but suggested a similar gradient, with egg size decreasing from southern to northern colonies. Lack (1968:279) mentioned this trend among certain congenerics in certain tropical Procellariiformes. A con- tinuum in egg size and shell weight between different populations from different areas was suggested in our specimens, especially in carolinensis, although shell thickness in the various subspecies seemed relatively stable. Whether or not the intrasubspecific tendencies are genetic is unknown. They are likely genetic, but standard measurements from museum skins are needed for further comparisons. The intersubspecific variations in egg size are most likely representative of body size (Eig. 1). If one assumes that egg size provides an index to body size, the large Texas birds may represent an intermediate between californicus and carolinensis. Brown Pelicans along the Pacific Coast [californicus) have the larger and thicker-shelled eggs (Table 2). Asmundson et al. (1943) showed that larger eggs in several species tended to have the thicker shells, but the essentially 18 THE WILSON BULLETIN M arc'll 1970 Vol. 82, No. 1 equal thicknesses from all our Gulf and Atlantic Coast eggs suggested that this relationship was not present on an intrasuhspecific basis. The small sample of eggs from Panama suggested that these eggs were most similar to the subspecies carolinensis, as Wetmore ( 1945) has shown with museum skins. Unfortunately, we were unable to obtain egg measurements from Ecuadorian or Peruvian Brown Pelicans. Murphy (1936:820) reported that the Peruvian pelicans are very large and we suspect that their eggs would also be larger and thicker-shelled. 4 he ecological significance of egg-size difference within a species is largely a matter of speculation. Lack (1966:7) suggests that egg-size differences between different species (and larger groups) are mainly a matter of heredity. The differences we observed on an intersubspecific basis in Brown Pelicans at least implied that these eggs are represented by relatively distinct gene-pools. Perhaps such gene-pools are even distinct on an intrasuhspecific basis. Mason (1945) showed that Llorida Brown Pelican movements, at least, are some- what restricted under normal circumstances, suggesting potential isolation between breeding groups. Welty (1962:408 quoting Murphy, 1936) also suggests that this species is potentially sensitive to isolating barriers. Possible Factors for Bias. — It is not our primary objective here to specu- late on taxonomic relationships on the basis of eggs; nonetheless, the varia- tions in eggs are expected to relate in some ways to taxonomic characters (Tyler, 1964, 1965). Our interest is mainly to examine natural variation in order to better understand if unnatural chans;e has occurred. Egg size and shell thickness and composition are known to vary with heredity, age, adult physiological condition, diet, and chemical influence (Romanoff and Romanoff, 1949:152—157, 359; Preston, 1958; Sturkie, 1965: 464, 487-488; Simkiss, 1967:157-197). Shell thickness also varies in dif- ferent areas of the egg of a given species, the most notable examples probably being the rock-nesting murres [Uria sp. ) and other seabirds, where thickness tends to increase at the most vulnerable parts (Tuck, 1960:25). Some inter- specific differences in thickness have been shown to be related to the hazards associated with placement on different nesting substrates ( Belopol’skii, 1957 : 133-134). Eortunately, egg collectors drilled their specimens at the girths, the most uniform area for most species (Romanoff and Romanoff, 1949: 157-158). Shell calcium (about 5 per cent) is utilized, as well, by developing embryos (Simkiss, 1967:198-213); hence, shell weight and also possibly thickness may be biased low if eggs of late-stage incubation are used in the shell-thick- ness or weight comparisons. Data combined into carolinensis and cali- fornicus categories indicated this trend (Table 3), although not significant statistically (T-test, P > 0.05) and only amounting to a small percentage Anderscin and Hickey BROWN PELICAN EGG AND BREEDING DATA 19 Shell Weights of Table 3 Phe-1943 Eggs of Two Subspecies of Bbown AT Diffekent Incubation Stages J’elican Subspecies Mean 95% Incubation Stage No. VVt. (g) C.L. carolineiisis First egg-3 days 98 9.75 0.21 4—12 days 230 9.88 0.14 13-21 days 53 9.76 0.28 caUjornicus First egg-3 days 92 10.75 0.20 4-12 days 121 10.97 0.25 13-21 days 30 10.59 0.40 Both First egg-3 days 190 10.23 0.16 4—12 days 351 10.26 0.14 13-21 days 83 10.06 0.24 in our sample (1-3 per cent). Therefore, we do not believe this bias to be important in the oological data examined here. Furthermore, the data sug- gested that most egg collectors tended to collect eggs that were about one- third or less incubated (Table 1), thus eggs in late-stage incubation repre- sented a small percentage of our sample. Although effects on the egg stemming from the age and physiology of the laying female would remain undetectable in oological samples, they would not be expected to affect an overall random, or essentially random, sample (see Asmundson et al., 1943). Eggshell Changes and Pesticide Residues. — The small samples of post-1949 specimens suggested thinning in all eggshells measured (Table 4) . Florida specimens showed a —17 per cent change in shell weight, Texas specimens a -20 per cent change, California specimens (Anacapa Is.) a —26 per cent change, and one set of eggs from Panama a —15 per cent change. All were significant iP < 0.05 ) changes. We could detect no change in shape in these post-1949 eggs {P > 0.05, Chi-square test). The incubation stages were essentially the same for both pre-1943 and post-1949 eggs (6 ± 2 days vs. 9 ± 5 days, 95 per cent C.L. ) . Size indices were not significantly different iP > 0.05), although the post-1949 eggs from Texas and Florida were slightly smaller in mean than those of pre-1943. Whether or not these changes in weight and thickness were associated with either recent declines of the Brown Pelican or environmental pollution, or both, remains to be determined. Stickel (1968) has stated that in Gulf Coast Brown Pelicans, pesticide residues were of approximately the same general magnitude as those of herons 20 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 Post-1949 Eggshell Table 4 Measurements of Brown Pelicans’ Subspecies caroUnensis caroUnensis caroUnetviis californicus Area Florida Texas Panama California Number 9 6 3 9 Wt. (g) 8.10 7.96 8.45 7.89 ±95% C.L. ±0.14 ±0.60 ±0.99 ±0.66 Size Index (cm-) 36.5 37.6 37.6 39.0 ±95% C.L. ±0.9 ±2.4 ±2.0 ±1.4 No. Subelliptical 1 2 2 7 No. Oval 8 4 1 2 Thickness Index- 2.22 2.12 2.25 2.02 ±95% C.L. ±0.09 ±0.10 ±0.22 ±0.12 Number - — 3 9 Tliickness (mm) — ■ 0.457 0.424 ±95% C.L. — ■ — ±0.012 ±0.018 1 Post-’49 eggs were collected as follows: Florida — 1950, 1953; Texas — 1951; Panama — 1952; California — 1962. 2 From Ratcliffe (1967): Thickness index = 10 X wt. in g/( length X breadth in cm). (Ardea cinerea) from Great Britain and Bald Eagles {Haliaeelus leucocepha- lus) in the United States (see Stickel et ah, 1966; and Moore and Walker, 1964). Risebrough et al. (1967) analyzing two Brown Pelican eggs from the Gulf of California found them to be generally “low” in pesticide content (0.7 ppm [wet-weight basis] DDT and metabolites and about one-fifth as much polychlorinated biphenyls [PCB’s], an industrial pollutant; endrin and dieldrin were also identified). They found an average of 0.8 ppm DDT- family residues (61 per cent DDE) and about two-thirds as much PCB in six Brown Pelican eggs taken in Panama. We converted the above residues to a ppm wet-weight basis by assuming 7 per cent fat in the eggs. We measured two of the eggshells from Risebrough’s study (Baja California specimens) and found one suggestive of a “normal” egg (11.7 g, 0.59 mm in thickness) and the other suggestive of thinning ( 9.3 g, 0.50 mm ) . Another study ( Anderson et al., 1969 ) showed that egg residues as low as 1 ppm of DDE, and possibly less, could be associated iP < 0.05) with detectable shell changes in White Pelicans, although egg residues may not always necessarily reflect residues in adults that could influence egg-shell deposition. Risebrough et al. (1967) reported 84.4 ppm of DDT-type residues, 91 per cent of which was p,//-DDE (77 ppm ) in the breast muscle of a Brown Pelican collected in California. These levels are only slightly lower than those reported from Lake Michigan Herring Gulls {Lams argentotus) , which averaged 80 ppm DDE in the breast of adult birds (Hickey et al., 1966). Reproduction in the Aiulcrsoii a?ul H ickey BROWN PELICAN EGG AND BREEDING DATA 21 Mean 1 Dates of Clutch FROM Various Able 5 Completion in Brown Pelicans Geographical Areas No. Mean Mean Area Clutches Date ± s.u. Stage Incubation! So. California 29 8 April ± 16 days 1.4 No. Baja California 61 10 April ± 54 days 1.8 Texas 36 9 May ± 18 days 1.5 Louisiana 14 27 April ± 31 days 1.6 Florida 75 29 May ± 125 days 1.9 South Carolina 14 5 June ± 17 days 1.7 Numerically coded with Table 1, cols. 1—2. Wisconsin Herring Gull population in Green Bay (characterized by egg- breakage ) is known to be severely affected by DDE and other residues (Keith, 1966; and Hickey and Anderson, 1968). Egg residues from the same population averaged 183 ppm DDE in 1963 and 1964 (Keith, 1966). Breeding Characteristies. — Pacific Goast data suggested that between north- ern Baja California and California, the breeding dates were somewhat closely related (Table 5). Gulf and Atlantic Goast birds, on the other hand, showed much variation, especially in Florida (Appendix 1) as discussed by Bent (1922:295) and Palmer (1962:277). Palmer’s (1962:275) distribution map suggests that on the Pacific Coast, the major breeding populations of californicus are concentrated into a smaller area than those from Gulf and Atlantic Coast sites (carolinensis) . Bent (1922:296 ), Howell (1932:85-87 ), and Lowery (1960:113-114) noted that Brown Pelicans of the subspecies carolinensis tended to utilize trees as well as coastal beaches and islands as nesting substrates. Murphy (1936:810-814) mentioned diverse breeding sites for South American pelicans as well. The Brown Pelicans of northern Baja California and California seem more generally restricted to ground- nesting on islands (Bent 1922:301; Williams, 1927). Bond (1942) reported tree-nesting for the California Brown Pelican as very unusual. In Florida, where the Brown Pelican still persists (Williams and Martin, 1969 ) , a long breeding season and diversity of nesting substrate seem to char- acterize breeding. They nest year-round in Peru, although considerable shift- ing of sites occurs (Murphy, 1936:821-822). The Gulf of Galifornia Brown Pelicans still persist as breeders, although there is no evidence of a longer breeding season than in colonies farther north (R. W. Risebrough, pers. comm. ) . Clutch sizes showed no significant variation ( P > 0.05 ) between any of the geographical areas listed in Table 2. The means, and our best estimates, for clutch-size in the Brown Pelican, are given in Table 1. Bent (1922:297)/ 22 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 and Palmer (1962:277) stated that three eggs, and less often two, is the normal clutch size; nests with four and five eggs have been found. Breeding Records. — The population estimates by egg collectors cited in Appendix 1 must be viewed eautiously. These estimates were subject to observer error; however, they can provide an approximation of changes that might have occurred. Data-slip information, although most likely sketchy, can also provide documentation of past breeding locations. The records we found in egg collections did not provide a complete picture of breeding lo- calities but suggested possible fluctuations in numbers over the years (Appen- dix 1). On the other hand, none of the major colonies seem to have been completely without birds since at least the late 1800’s. Numbers probably increased on Anacapa Island, California, during the late 1920’s. Williams (1927) reported a colony as far north as Point Lobos, California, during this time. The late 1920’s may represent a period of population increase. Bond 1 1942 ! reported the estimated numbers on Anacapa Island from 1898 to 1941 to be highly fluctuating ( estimates ran from about 200 to at least 2000 pairs). Banks (1966) reported eggs and young on Anaeapa and essentially “normal” numbers of breeding birds, at least in 1963 and 1964, two years after the thin-shelled eggs reported here. The Los Coronados birds seem historically more stable (Appendix 1). It is certain that both Anacapa and Los Coronados breeders were historically present in large numbers (Banks, 1966). Risebrough (1968) and Schreiber and DeLong (1969) suggested that the Brown Pelican has decreased considerably in recent years off Cali- fornia, including no known breeders on Los Coronados in 1968. Perhaps the —20 to -26 per cent figure in shell change represents or approaches the lower limit to which eggs may survive to be collected by egg-collectors. Certainly, some production occurred in the California colony with these shell- changes, although present numbers suggest a declining population. Lowery (1960:113-114) mentions large colonies in Louisiana; yet Winckler (1968), in a popular article, summarized their nearly virtual disappearance from the Gulf Coast by 1968. In the light of the better-known demise of Gulf Coast Brown Pelicans, we believe the status of California Brown Pelicans and populations farther to the south needs immediate study. SUMMARY Mean clutch size in 236 sets of North American Brown Pelican eggs was 2.95 and did not vary geographically between North American populations. Shell weight varied from 8.05 g to 10.99 g along a geographic continuum. Shell thickness averaged 0.510 mm for Pelecanus occidentalis occidentalis, 0.554-0.557 mm for P. o. carolinensis, and 0.569- 0.579 mm for P. o. californicus. The ranges of breeding dates for the more southern populations were wider than those of northern ones. Small numbers of eggs taken in Texas and Florida after 1949 were 20 per cent below normal weight; 1962 eggs from California were 26 per cent below normal; and three Anderson ami Hickey BROWN PELICAN EGG AND BREEDING DATA 23 taken in Panama, 15 per cent heluw normal. Shell thickness had likewise decreased 15“27 per cent. .4CKNOWLEDGMENTS This study was carried out as part of a contract with the Bureau of Sport Fisheries and Wildlife, Fish and Wildlife Service, U.S. Department of the Interior, Patuxent Wildlife Research Center, Laurel, Maryland. We are grateful to the many curators of museum collections listed in Appendix 1. The private collectors cited in Appendix 1 were extremely cooperative. We are especially grateful to Ed N. Flarrison and Wilson C. Flanna for their personal assistance and extremely helpful suggestions. Mr. Harrison, in addition, located our 1962 samples of California eggs. Lucille F. Stickel and Eugene H. Dustman provided critical advice, and Ralph W. Schreiber suggested the iimnediate consolidation of our Brown Pelican data. Mrs. Pearl Davis punched our data cards, and the College of Agricultural and Life Sciences, University of Wisconsin, provided computer facilities at no cost. We are grateful to J. 0. Keith and R. W. Risehrough for critical advice on the manuscript. Brown Pelican Breeding OOLOGICAL APPENDIX 1 Records taken from North American Records and Collections. Estimated Numbers; Museum* Date Location Remarks Observer of record Southern California 27 May 1893 Anacapa Is. — A. H. Miller 2 5 June 1910 Anacapa Is. 500+ pairs G. Willett 3,5 7 Alar. 1916 Anacapa Is. — M. C. Badger 2 2 Mar. 1917 Anacapa Is. — M. C. Badger 3 15 May 1919 Anacapa Is. • — — 1 7 Alar. 1920 Anacapa Is. 5,000+ pairs S. B. Peyton 30 8 Alar. 1922 Anacapa Is. — S. B. Peyton 5 28 Mar. 1927 Anacapa Is. — — 3 24 Feb. 1929 Anacapa Is. — C. W. Ashworth 2 1 Alar. 1936 Anacapa Is. — E. Harrison 3 1 Alar. 1936 Anacapa Is. 2,000+ pairs L. T. Stevens 14 12 Mar. 1939 Anacapa Is. “large colony” L. T. Stevens 4,7 19 Alay 1919 San Miguel Is. — — ■ 1 25 Alay 1927 Point Lobos 8-10 nests L. Williams (1927) 2 Baja California, M exico 18 Apr. 1894 Los Coronados — E. Parker 27 19 Apr. 1894 Los Coronados — — 1 4 Apr. 1895 Los Coronados — A. Hewitt 2,22 19 Apr. 1898 Los Coronados — A. J. Kellog 24 27 Apr. 1898 Los Coronados ■ — — 3 6 May 1904 Los Coronados — 0. C. Polling 2 6 Apr. 1908 Los Coronados 500 nests P. 1. Osborne 1,4 24 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 (APPENDIX 1 CONTINUED ) Date Location Estimated Numbers; Remarks Observer Museum* of record 6 Apr. 1908 Los Coronados A. Van Rossem 25 1 July 1908 Los Coronados ■ P. 1. Osborne 9 4 Apr. 1910 Los Coronados — P. I. Osborne 29 2 Apr. 1912 Los Coronados — C. S. Thompson 23 1 Apr. 1913 Los Coronados 500 nests L. M. Huey 3 29 Mar. 1914 Los Coronados — W. C. Bradbury 2,9 31 May 1915 Los Coronados — 1. D. Nokes 5 26 Mar. 1917 Los Coronados 500 pairs N. K. Carpenter 6 4 May 1917 Los Coronados — D. S. DeGroot 2 11 Apr. 1919 Los Coronados • — N. K. Carpenter 23 12 May 1921 Los Coronados — W. C. Hanna 4 30 Mar. 1922 Los Coronados — — 1 15 Apr. 1881 Mexican coast — — 1 26 Mar. 1917 So. Coronados, SE slope — — 1 6 Apr. 1920 Todos Santos Is. — G. Bancroft 4 6 Apr. 1920 Todos Santos Is. — J. Burnham 26 17 Apr. 1921 San Pedro Nolasco Is. — — 1 2 May 1921 Granite Is. — 1 7 Apr. 1932 San Benito Is. — E. Harrison 3 10 Apr. 1932 San Martin Is. — E. Harrison 3 2 June 1932 Asuncion Is. — E. Harrison 3 Panama 15 Feb. 1942 Chama Is., Panama Bay, Panama • A. Wetmore 13 15 Mar. 1952 Taboga Is., Panama — A. Wetmore 13 T exas 10 May 1886 Near Corpus Christi F. B. Armstrong 12 20 May 1888 Neuces Co. - — T. S. Gillin 4 10 Apr. 1889 So. Bird Is., Laguna Madre — J. A. Singley 2 16 Apr. 1889 So. Bird Is., Laguna Madre — J. A. Singley 4.25 14 June 1894 25 mi. from Corpus Christi — F. B. Armstrong 1 14 May 1896 So. Bird Is., Laguna Madre — D. B. Burrows 2 28 May 1910 Near Corpus Christi — C. E. Farley 30 30 May 1910 Near Corpus Christi — J. M. Carroll 4 3 May 1912 Laguna Madre — J. M. Priour 4 18 May 1913 Neuces Co. — F. B. Armstrong 9 27 May 1915 Padre Is. — F. B. Armstrong 2 19 May 1917 Big Bird Is., Laguna Madre — R. W. Quillan 19 Atulerson and Hickey BROWN PELICAN EGG AND BREEDING DATA 25 (APPENDIX 1 CONTINUED) Date Location Estimated Numbers; Remarks Observer Museum* of record May 1919 Is. off so. coast — 3 15 May 1919 Laguna Madre — H. Brandt 10 5 May 1922 Neuces Co. — G. Stewart 11 24 May 1925 Pelican Is., Aransas Bay — R. D. Camp 31 1951 Refugio Co. — T. C. Meitzen 18 Louisiana 29 Mar. 1893 Lost Is. — F. A. Mcllhenny 2 28 Mar. 1894 Marsh Is. — F. A. Mcllhenny 2 29 Mar. 1894 Shell Keys — F. A. Mcllhenny 2,23 3 June 1919 Pass a rOutre — E. R. Kalmbach 13 5 June 1919 Errol Is. — J. D. Figgins 9 26 May 1938 North Is. — F. Tobin 10 13 Apr. 1940 La Fourche Par., G. H. Lowery Timbalier — (1960) 17 Florida 15 Mar. 1879 Near Marco — 1 1 Apr. 1880 Indian R. — C. L. Gass 26 15 Apr. 1880 Indian R. — — 1 29 Apr. 1880 Old Tampa Bay — — ' 1 12 Apr. 1890 Lee Co. • — H. R. Jamison 4 12 Apr. 1890 Charlotte Harbor — S. Reiff 21 3 May 1890 W. of Pine Is., Lee Co 225 nests N. K. Jamison 4 26 Apr. 1891 Pelican Is. — M. Gibbs (1894) 9 12 Apr. 1892 Tampa Bay — D. P. Ingraham 27 10 May 1893 Pelican Is. — J. M. South wick 4 5 June 1893 Mullett Key — B. T. Smith 26 .30 June 1894 Tampa Bay — — 1 21 Jan. 1896 Pelican Is. 500 pairs B. W. Evermann 23 3 Apr. 18% Pelican Is. — H. E. Pendry 3 30 Apr. 1896 Seminole Is. — H. E. Pendry 5 18 May 18% Rookery Is., off Diston City ■ — W. Meyor 8 15 May 1899 Brevard Co. — F. S. Webster 10 19 Apr. 1908 Boca Grande, Charlotte Keys 200 birds P. B. Phillipp 12 20 Apr. 1908 Charlotte Harbor, Devilfish Key — P. B. Phillipp 12 3 May 1911 Pelican Is. — P. B. Phillipp 12 19 May 1911 Hillsborough Co. — 0. E. Baynard 24 27 Apr. 1913 Lee Co. - — • 0. E. Baynard 3,9 27 Apr. 1913 Roco Bay, Pinellas large colony 0. E. Baynard 8 Co. in trees 26 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 (APPENDIX 1 CONTINUED) Date Location Estimated Numbers; Remarks Observer Museum* of record 15 May 1918 Tampa Bay — J. L. Vauglin 4 20 Apr. 1920 Tampa Bay — — 3 17 May 1921 Tampa Bay - — J. L. Vauglin 2,20 17 May 1921 Tampa Bay — W. F. Lewis 8 27 May 1921 Tampa Bay — J. L. Vaughn 23 28 Dec. 1921 Pelican Is. — T. D. Burleigh 10 20 Apr. 1926 Pinellas Co. — C. E. Doe 16 1 .June 1926 Merritt Is. — K. Squires 2 10 June 1929 Merritt Is. 2,500 pairs J. C. Howell, Jr. 12 28 Mar. 1930 Lee Co. C. E. Doe 16 25 Apr. 1930 Near BolceJia? — C. E. Doe 16 JO Apr. 1931 Alosquito Lagoon, Brevard Co. 2,000 ± nests W. H. Nicholson 23 6 June 1931 Pine Is. Res., Bird Key — R. W. Williams 13 7 June 1931 Matlaclia Pass Res., 6-mi. Is. — R. W. Williams 13 3 May 1932 Bird Key, Hillsltorough R. E. Gammell 7 Co. 22 Apr. 1934 Rattlesnalce Key, Levy Co. — C. E. Doe 16 9 Mar. 1950 Is., n. side of Cocoa — Cocoa Beaclt 375 nests C. E. Carter 15 10 Mar. 1953 Merritt Is. — H. Brandt 10 Georgia 16 June 1898 Cliatliam Co. on Jteacli T. D. Perry 1,16 South Carolina 10 May 1901 Bird BanJv, BuJJ’s Bay — M. T. Cleckley 9 20 June 1901 Near CliarJeston on Iteacli — 3 23 June 1901 Bay Point, near Beaufort “large colony” M. T. Cleckley 3 23 May 1915 Bird Banli, BuIJ’s Bay — A. C. Bent 13 18 June 1915 Bird Banlc, Bull’s Bay — A. Sprunt, Jr. 30 7 JuJy 1916 BuJJ’s Bay — M. T. Cleckley 28 3 June 1925 BuJJ’s Bay — W. B. Savary 5 14 June 1934 Georgetown Co. — H. L. Harllee 14 20 June 1942 BuIJ’s Bay — E. J. DeCamps 14 10 June 1943 St. Helens Sound, Beaufort (Bird Banlc) — E. J. DeCamps 4 10 July 1943 18 mi. e. Beaufort — E. J. DeCamps 14 Cuba 8 Sep. 1930 CacacJiita Bay — P. Bartsch 13 * Mii.seums and collections are numbered as follows: 1. Calif. Acad. Sci., San Francisco; 2. Mns. Vert. Zool., Univ. Calif., Berkeley; 3. Western Found. Vert. Zool., Los Angeles, Calif.; 4. San Bernardino Co. Mns., San Bernardino, Calif.; 5. S. B. Peyton, private collection, Fillmore, Calif.; 6. Oakland Publ. Mns., Oakland, Calif.; 7. Santa Barbara Mns. Nat. Hist., Santa Barbara, Antlerson anil Hickev BROWN PELICAN EGG AND BREEDING DATA 27 Calif.; 8. San Diego Miis. Nat. Hist., San Diego, Calif.; 9. Denver Mus. Nat. Hist., Denver, Colo.; 10. Carnegie Mus., Pittsburgh, Pa.; 11. Philadelphia Acad. Sci., Philadelphia, Pa.; 12. Amer. Mus. Nat. Hist., New York, N.Y.; 13. U.S. Natl. Mus., Wash., D.C.; 14. Zoological Mus., Clemson Univ., Clemson, S.C.; 15. C. E. Carter, private collection, Orlando, Fla.; 16. Fla. State Mus., Gaines- ville; 17. L.S.U. Mus. Nat. Sci., Baton Rouge, La.; 18. T. C. Meitzen, private collection, Refugio, Tex.; 19. R. W. Quillan, private collection, San Antonio, Tex.; 20. Univ. Kans. Mus. Nat. Hist., Lawrence; 21. Univ. Nebr. Zool. Dept. Mus., Lincoln; 22. Cleveland Nat. Sci. Mus., Cleveland, Ohio; 23. Royal Ont. Mus., Toronto; 24. Joseph Moore Mus., Earlham Coll., Richmond, Ind.; 25. Ohio State Mus., Ohio State Univ., Columbus; 26. Univ. Mich. Mus. Zool., Ann Arbor; 27. Janies Ford Bell Mus. Nat. Hist., Univ. Minn., Mpls.; 28. M. Pollock, private collection, Edmonton, Alta.; 29. Burke Memorial Mus., Univ. Wash., Seattle; 30. Puget Sound Mus. Nat. Hist., Univ. Puget Sound, Tacoma; 31. Zoology Mus., Ore. State Univ., Corvallis. LITERATURE CITED American Ornithologists’ Union. 1957. Check-list of North American birds. Fifth ed. American Ornithologists’ Union. 1968. Report of committee on conservation, 1968. Auk, 85:669-677. Anderson, D. W., J. J. Hickey, R. W. Risebrough, D. U. Hughes, and R. E. Christensen. 1969. Significance of chlorinated hydrocarlion residues to breeding pelicans and cormorants. Canadian Field-Naturalist, 83 :91-112. Asmundson, V. S., AND G. A. Baker. 1940. Percentage shell as a function of shell thick- ness, egg volume and egg weight. Poultry Sci., 19:227-232. Asmundson, V. S., G. A. Baker, and J. T. Emlen. 1943. Certain relations between the parts of birds’ eggs. Auk, 60:34-44. Banks, R. C. 1%6. Terrestrial vertebrates of Anacapa Island, California. Trans. San Diego Soc. Nat. Hist., 14:173-188. Belopol’skii, L. 0. 1957. Ecology of sea colony birds of the Barents Sea. Israel Prog, for Scientific Translations, Jerusalem, 1961. Trans, by R. Ettinger and C. Salzmann. Bent, A. C. 1922. Life histories of North American petrels and pelicans and their allies. U.S. Natl. Mus. Bull., 121. Bond, R. M. 1942. Banding records of California Brown Pelicans. Condor, 44:116-121. Conney, a. H. 1967. Pharmacological implications of microsomal enzyme induction. Pharmacol. Rev., 19:317-366. Gibbs, M. 1894. Nesting habits of the Brown Pelican in Florida. Oologist, 11:81-84. Hickey, J. J., J. A. Keith, and F. B. Coon. 1966. An exploration of pesticides in a Lake Michigan ecosystem. J. Appl. EcoL, 3(Suppl.) : 141-154. Hickey, J. J., and D. W. Anderson. 1968. Chlorinated hydrocarbons and eggshell changes in raptorial and fish-eating birds. Science, 162:271-273. Howell, A. H. 1932. Florida bird life. Coward-McCann, New York. Keith, J. A. 1966. Reproduction in a population of Herring Gulls {Lams argentatus) contaminated by DDT. J. Appl. Ecol., 3(Suppl.) :57-70. Kupfer, D. 1%7. Effects of some pesticides and related compounds on steroid function and metabolism. Residue Reviews, 19:11-30. Lack, D. 1966. Population studies of birds. Clarendon Press, Oxford. Lack, D. 1968. Ecological adaptations for breeding in birds. Metbuen, London. Lowery, G. H., Jr. 1960. Louisiana birds. Louisiana State Univ. Press, Baton Rouge. Mason, C. R. 1945. Pelican travels. Bird-Banding, 16:134-143. Moore, N. W., and C. H. Walker. 1964. Organic chlorine insecticide residues in wild birds. Nature, 201 :1072-1073. Murphy, R. C. 1936. Oceanic birds of South America: Vol. I-H. Amer. Mus. Nat. Hist., New York. 28 THE WILSON BULLETIN March IhTO Vol. 82, Nil. 1 Palmer, R. S. [Ed.] 1962. Handbook of North American birds: Vol. I. Yale Univ. Press, New Haven. Peakall, D. B. 1967. Pesticide-induced enzyme breakdown of steroids in birds. Nature, 216:505-506. Preston, F. W. 1958. Variation of egg size with age of parent. Auk, 75:476-477. Preston, F. W. 1%8. The shapes of birds’ eggs: mathematical aspects. Auk, 85: 454-463. Ratcliffe, D. a. 1967. Decrease in eggshell weight in certain birds of prey. Nature, 215:208-210. Risebrough, R. W. 1968. Pollution, wildlife and science. Canadian Field-Naturalist, 82:241-243. Risebrough, R. W., D. B. Menzel, D. J. Martin, Jr., and H. S. Olcott. 1967. DDT residues in Pacific sea birds: a persistent insecticide in marine food chains. Nature, 216:589-591. Risebrough, R. W., P. Rieche [= Reiciie], D. B. Peakall, S. G. Herman, and M. N. Kirven. 1968. Polychlorinated biphenyls in the global ecosystem. Nature, 220: 1098-1102. Romanoff, A. L., and A. J. Romanoff. 1949. The avian egg. Wiley, New Vork. ScHREiBER, R. W., AND R. L. Delong. 1969. Brown Pelican status in California. Audu- bon Field Notes, 23:57-59. SiMKiss, K. 1%7. Calcium in reproductive physiology. Reinhold, New York. Steel, R. G. D., and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill, New York. SncKEL, L. F. 1968. Organochlorine pesticides in the environment. 2d Meeting on the Unintended Occurrence of Pesticides in the Environment, 19 Sept. 1%7, Tay- mouth Castle, Scotland. Mimeo. Stickel, L. F., N. j. Chura, P. A. Stewart, C. M. Menzie, R. M. Prouty, and W. L. Reichel. 1966. Bald Eagle pesticide relations. Trans. N. Amer. Wildl. and Nat. Resources Conf., 31:190-200. .Storer, T. I. 1930. A critique of oological data. Auk, 47 : 329-334. Sturkie, P. D. 1965. Avian physiology. Comstock, Ithaca, New York. Tuck, L. M. 1960. The murres. Canadian Wildl. Ser. 1, Canadian Wildl. Serv., Ottawa. Tyler, C. 1%4. Wilhelm von Nathusius, 1821-1899, on avian eggshells. Berkshire Printing Co., Reading. Tyler, C. 1965. Egg-shell characteristics as a guide to taxonomy. Ibis, 107:131. Welty, j. C. 1962. The life of birds. W. B. Saunders, Philadelphia. Wetmore, a. 1945. A review of the forms of the Brown Pelican. Auk, 62:577-586. Williams, L. 1927. California Brown Pelicans nesting at Point Lobos, Monterey County, California. Condor, 29:246-249. Williams, L. E., Jr., and L. Martin. 1969. Nesting status of the Brown Pelican in Florida in 1968. Quart. J. Florida Acad. Sci., 31:130-140. WiNCKLER, S. 1%8. Brown Pelican epitaph. Texas Parks and Wildlife, 26 (12) :24-28. WuRSTER, C. F., Jr. 1969. Chlorinated hydrocarbon insecticides and avian reproduc- tion: how are they related? In Miller, M. W. and G. G. Berg (Eds.). Chemical fallout: Current research on persistent pesticides. C. C Thomas, Springfield, Illinois. DEPARTMENT OF WILDLIFE ECOLOGY, UNIVERSITY OF WISCONSIN, MADISON 53706. 12 MAY 1969. NICHE OVERLAP IN FEEDING ASSEMBLAGES OF NEW GUINEA BIRDS John Terborgh and Jared M. Diamond A SINGULAR opportunity for assessing the degree of niche overlap among elements of tropical avifaunas exists in the phenomenon of feeding trees. These contain fruit, flowers or some other food source that attracts numhers of animals, among which birds usually predominate. Since only a single commodity is available in most feeding trees, it is possible to compare the harvest by different species through some appropriate measure of tree usage. Consumption of a common resource by a number of species implies niche overlap and suggests that a state of competition at least potentially exists among the species. The striking concentrations of birds that are frequently attracted to feeding trees in New Guinea have been remarked upon previously by observers working at widely scattered localities I Mayr and Rand, 1937 ; Rand, 1942o and b\ Ripley, 1964). In their recent Handbook of New Guinea Birds, Rand and Gilliard (1967) comment on the significance of this phenomenon and point out the need for a systematic study. The present paper gives an account of observations made at 20 feeding trees in the Eastern Highlands District of the Territory of New Guinea. Repeated censuses of the bird assemblages in each tree led to a time-dependent measure of feeding for each species present. The results allow estimates of the degree of niche overlap among the species taking certain classes of food (e.g., flowers, small fleshy fruits) and indicate the diversity of food sources exploited by particular species or groups of species. METHOD On finding an active feeding tree the oliserver sought the most advantageous viewing station, i.e., the point on the ground from which optimal lighting and visibility of the crown was obtained. In exceptional cases the entire face of a tree could he observed, hut far more commonly intervening foliage reduced the exposure to a part of the crown or even a few branches. Consequently a large fraction of the birds using most trees was not seen. Each tree studied was observed for one to several Mj or 1 hour periods, each of which was comprised of a succession of two-minute censuses. The exposed portion of the feeding tree was systematically scanned with a pair of 8 X 30 binoculars for approximately 1 minute and 45 seconds. During this time the observer accrued a mental tally of all the species and individuals seen. The remaining 15 seconds of these censuses wore used to record the data. The two-minute census was selected when it was found that this was about the maximum time over which the observer could keep track of a cumula- tive mental tally of species and individuals in an active tree. It was a policy to maximize 29 30 THE WILSON BULLETIN Marcli 1970 Vul. 82, No. 1 the number of individuals rather than distribute the observation time evenly over all parts of the tree. No particular effort was made to find different birds with each new census, and thus the same individuals were often recorded for a number of successive censuses. A unit of tree-usage was derived from the census data on the assumption that a single sighting represented an average stay of two minutes in the tree. The justification of this assumption lies in the fact that the canopy area under observation was generally several times larger than that covered in one binocular field. Thus it was possible, on the one hand, for birds to come and go from the visible portion of the tree and escape detection, and on the other, for birds to remain visilde for nearly 4 minutes and yet be recorded in only one census. Since each observation represents a bird-usage of 2 minutes, the identification of one bird in each of the 30 censuses in a one-hour observation period would add up to a total of one bird-hour of tree usage. The number of bird-hours recorded in an observation period of any length is thus the aggregate of individual sightings divided by the number of two-minute censuses. Once it had been ascertained several times that a species was actually taking food, all further individuals were tallied on the premise that they were in the tree for the purpose of feeding. The unexpected scarcity of transient species in feeding trees made it evident that virtually all the Ijirds recorded in them had entered specifically to feed. In general the majority of individuals in a tree at any time were actively feeding, though social interactions or periods of rest or preening resulted in frequent brief interruptions. The identification of more than 90 per cent of the bird species included in this report was confirmed by specimens collected in the localities of the trees but not from the trees themselves. Nomenclature follows that of Rand and Gilliard (1967). The feeding trees unfortunately cannot be identified since our collection of preserved plant material was lost. Thus brief descriptions from our field notes of the trees and their flowers or fruits must suffice. All of the observations were made during the period of .June to August, 1%4. in the Eastern Highlands District of the Territory of Papua and New Guinea. A synopsis of the localities mentioned in the text follows. Karimui Patrol Post lies about 70 miles southwest of Goroka at 3,650 feet in an extensive mountain basin. Udo, Mao, Sordida, and Palea are native hamlets in the vicinity of Karimui. A flowering tree on the north bank of the Sena River was about 14 miles northeast of Karimui at an elevation of approximately 4,.500 feet. A fruit tree near the village of Mengino I was at about 4,800 feet on the west slopes of Mt. Michael in the area administered from Tufa Patrol Post. Two localities were villages in the Fore language are administered from the Okapa Patrol Post, which is 36 miles southeast of Goroka: Miarassa at 5,800 feet and Okassa at about 3,500 feet. RESULTS Bird-usage data were recorded from nine flowering trees or lianas of four species, ten fruiting trees of at least six species, and one tree whose bark at- tracted large numbers of parrots. We will consider results from each of these general classes of feeding trees in order. FEEDING ASSEMBLAGES IN FLOWERING TREES White- flowered trees. — We were fortunate in locating five individuals of one species of flowering tree within a radius of IM; miles of Karimui Patrol Post. These trees carried great numbers of dense umbel-like flower heads. Tcrborgh and Diainoinl z, ■/} — D 1^: r NEW GUINEA EEEDING ASSEMBLAGES i|j o C X •— O O -T d C-J CO O CO I-- lO -r » 0 o o -t o d 'M o d ^ o d d cc I- o I ' o d t- fO -o X O O O lO d d d d l/t) lO rO O d X lO o CM r-^ 0 0 — 00 d d d — d — -t CM o o oxior-' — d d d d d I - O CM X O X CM CM d d d d m »-/* -r* X — U r> r- o d p d o d t-- ro I- t- O lo d d o O fC P o lO d o d o d C5, — X o P X p o o o d £ I V/ O 5^ ?JC . > "O O I- ? -t 5- £ ;:; o CO -£; •- ■ 31 C X o o •:2 o • ^ u 5 C I j N ^ C' «-C' ® X ^ J= N 32 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 The individual blossoms were 3-4 mm across with conspicuous white petals and somewhat swollen glandular receptacles. All but one of the five trees stood at the edge of wide trails through original forest, the exception ( Udo-2 ) being located in the forest some 200 yards to the side of a trail. Estimates of their heights fell between 100 and 120 feet, of which their leafy crowns comprised the up}>er 30-50 feet. The bird usage of these trees was recorded in 2 to 5 one-hour observation periods. The results of repeated observations at a single tree showed little variation in the rank order of the 6 most frequent species (Table lA ) . Bird-hour totals varied somewhat more and were particularly influenced by the large groups of lorikeets whose movements in and out of the tree were erratic. In general, the variation in results from different trees of the same species was greater than that among different readings from the same tree. Averaged records from the five white-flowered trees are given in Table IB. The preponderance of honeyeaters is immediatly apparent. Members of this family alone accounted for 67-88 per cent of the species seen in these trees but comprised only 53 per cent of the observations. The small lorikeet, Charmosyna placentis was by far the most numerous species and accounted for 37 per cent of all observations. The list of species showed little variation from one tree to another, most of the exceptions being transients or occasional visitors. Of the 11 species that were regular users of these trees, all 11 oc- curred at two trees, 10 at one tree, and 9 at the remaining two trees. While these trees were under observation, it became apparent that two of them were giving anomalous results with respect to the frequencies of some species. The third Udo tree attracted extraordinary numbers of Oedistoma pygmaeitni and the Myzomela honeyeaters, while Oreornis obscurus was com- paratively scarce. In contrast, at the Sordida tree the frequency of Myzomela nigrila was a factor of 10 less than in the third Udo tree and that of Oreornis obscurus was 30 times greater while Myzomela cruentata was altogether absent. We suspected that these anomalous frequencies may have resulted from the facts that only the topmost branches of the third Udo tree were visible and that only the lower portion of the crown of the Sordida tree could be observed. This possibility was tested with the three white-flowered trees whose full crowns were visible. All subsequent observations on these trees noted whether the birds had been seen above or below imaginary horizontal bisectors of the crowns. A total of 965 sightings of 10 species were distributed, 51 per cent in the upper and 49 per cent in the lower halves of the crowns (Table 2). All but Charmosyna placentis, Toxorhamphus iliolophus, and Xanthotis polygramma were more or less unevenly distributed. The species that were disproportionately abundant in the third Udo tree, Oedistoma pygmaeum and the three Myzomela honeyeaters, were found to keep largely Terhorgh and Diamond rsEW GUINEA EEEDING ASSEMBLAGES 33 Table 2 Vertical Distribution of SOME Bird Species IN Three White-flowered Trees IN THE KaRIMUI Region. Probabilities FROM Two -TAILED Standard Normal Variable Test. Species No. of Per cent in Observations Upper Half Per cent in Lower Half P Parrots Charmosyna placentis 214 48 52 0.32 Honeyeaters Oedistoma pygnuieum 176 66 34 0.001 Myzomela eques 9 67 33 0.33 Myzomela cruentata 2 100 0 • — Myzomela nigrita 77 94 6 0.001 Toxorhamphus iliolophus 25 52 48 0.92 Oreornis obscurus 14 0 100 0.001 Xanthotis chrysolis 101 31 69 0.001 Xanthotis polygramnui 79 46 54 0.35 Meliphaga spp. (six species) 256 36 64 0.001 Total 965 51 49 to the upper branches. On the other hand, Oreornis obscurus appeared ex- clusively in the lower branches of the test trees, thus accounting for its extreme scarcity in the third Udo tree and relative abundance in the Sordida tree. These data suggest that much of the observed tree-to-tree variation was due to fortuitous differences in the visibility of the canopy. When these differences are taken into consideration it is apparent that the pattern of usage of the 5 white-flowered trees was notably consistent. As the minimum distance be- tween any two of these trees was approximately Vi mile, there was probably very little overlap in the populations of most passerine species that were using them. Back and forth movements of lorikeets were much more likely, since they always travelled in flocks which appeared to range over wide areas. Consequently, usage data were least consistent for lorikeets, which at any moment were either present in numbers or altogether missing. Lavender-flowered elimbers. — The cjuestion of how as many as a dozen species of nectar-feeding birds can share a common food source may in part be answered by the degree of ecological isolation afforded by vertical stratifi- cation. The effectiveness of this behavioral mechanism in achieving a partial separation of potential competitors is indicated by the results from two flowering climbers. These enveloped the trunks of forest trees located at the edge of trails where more sunlight etitered than in the heart of the forest. 34 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 Somewhat drooping horizontal branches carried at their ends large showy panicles of lavender campanulate flowers 4-6 mm across. The foliage and flowers were borne from about 15 feet above the ground to the base of the canopy at about 75 feet. Ihe combined results of 7 one-hour observation periods at two of these climbers located about 2 miles apart are given in Table 4. Of the 11 species of lorikeets and honeyeaters that were regular users of the white-flowered trees, seven were also frequent at the climbers. The four missing species were honeyeaters, Toxorhamphus iliolophus and the three Myzomela species, of which the Myzomelas had all shown strong affinities for the upper layer of the canopy. Oedistoma pygmaeum, which was also found to inhabit the upper canopy, was approximately 30 times less frequent in the climbers than in the white-flowered trees. The two honeyeaters that appeared in the climbers but not in the white-flowered trees, Glycichaera fallax and Pycnopygius ixoides, not unsurprisingly, are birds of the understory. Glycichaera is ap- parently a rarity at Karimui, since we were unable to obtain a specimen and have no other records of it. On the basis of measured and observed vertical distributions of flower feeding birds at Karimui, we have compiled a list of species ranked in order of their presumed elevational preferences from the top of the canopy down- wards (Table 3). By far the largest group (II) is composed of species that range more or less freely through a large part of the vegetational column. The Myzomela honeyeaters of group I appear to live exclusively in the high canopy from 80-150 feet above the forest floor. The birds of group III range up to 30-50 feet but rarely if ever use exposed crowns for feeding. Niche overlap between the species of groups I and III is thus almost entirely avoided. Maximum niche overlap occurs between the species within a group. Varying degrees of interaction can be expected between the birds of group II and those of groups I and III. Overall usage of the flowering climbers, as with the white-flowered trees, was heavily dominated by lorikeets and honeyeaters (91 per cent). Mac- ropygia sp. (6 per cent) and Zosterops minor (2 per cent) made up most of the remainder, the latter also having occurred less frequently in the white- flowered trees. The seven species that were regular in both the white-flowered trees and the climbers (Trichoglossus haematodus, Charmosyna placentis, Oedistoma pygmaeum, Oreornis ohscurus, Xanthotis chrysotis, X. poly- gramma, and Meliphaga spp. ) comprised 82 per cent of the total usage of the former and 83 per cent of the latter. This result implies particularly broad niche overlap between these species despite considerable differences between many of them in size and structure. Hibiscus flowers. — A third type of flowering tree at Karimui deserves Tcrborgli and Diamond NEW GUINEA EEEDING ASSEMBLAGES 35 Table 3 List of Bird Species Feeding on Flowers in the Karimui Region in Order OF Presumed Elevational Preference in Forest Vegetation. Variety of feeding trees used by each species is indicated in the right hand column. F = flowers; SF = small fruits; Ficus = Ficus fruits; B = hark excrescence. Gromo Species Elevational Preference Classes of feeding Trees Visited Myzoinela cruentata F I Myzomelu nigritu upper canopy only F Myzomelu ec/ites F Oedistoma pygmaeum F Toxorhamphus iliolophus canopy F Chcirmosyna placentis and F,B II Xanthotis polygramma middle F.SY, Ficus Meliphaga spp. levels ¥,SF,Ficus Xanthotis chrysotis F,SF,Ficus Trichoglossus haematodus F,Ficus,B Oreornis obscurus F,SF, Ficus Zosterops minor middle and lower F III Macropygia sp. levels exclusive F,SF Pycnopygius ixoides of canopy F,SF mention because of its location at the edge of a native garden perhaps a half-mile from the nearest forest. A small spreading tree of the Hibiscus tribe, it carried numbers of showy red blossoms 4 to 6 cm across. In one hour we recorded 2.4 bird-hours of usage, all by small bands of the sylviid, Gerygone chloronota (Table 4) . These birds always moved together in groups of 2-6 and kept up a nearly continuous flow of soft vocalizations while they probed between petals at the bases of the large corollas. Although we visited this tree on several occasions, none of the forest nectar feeders was observed there. This negative result may not be significant in itself, but reinforces our general impression that open and second growth habitats in New Guinea have notably impoverished avifaunas in comparison, for example, with tropical South America (Diamond and Terborgh, 1967). The virtual absence of such habitats above 1,000 feet over most of the island prior to the recent expansion of the native population in the highlands is probably the explana- tion for this fact. River Sena orange-flowered tree. — Observations at a fourth type of flower- ing tree were made at a locality lying a full day’s walk to the northeast of Karimui at an elevation approximately 850 feet higher ( about 1.500 feet ) . This tree overhung the north bank of the Sena River and was viewed con- 36 THE WILSON BULLETIN March 11)70 Vdl. 82, No. 1 veniently from a large boulder in midstream. Its relatively small crown overtopped the nearby foliage and rose well over 100 feet above the forest floor. A heavy bloom of tiny flowers, 3-5 mm in diameter borne in dense heads, gave a yellow-orange cast to the whole crown. Oedistoma and My- zomela honeyeaters accounted for an unusually high portion of the usage (67 per cent), a finding that corroborates the observation that these species concentrate their feeding in the highest parts of the canopy. The species composition of the feeding assemhlage was not one that would have occurred at Karimui. The presence of Charinosyna pulchella, Myzomela cruentalus, M. rosenbergii, and Melidectes torquatus, all absent or uncommon at Karimui, can best be attributed to the higher elevation of the Sena River site, since these are known to be montane rather than lowland forms ( Mayr, 1941 ) . The absence of some expected species (e.g., Meliphaga sp.) was perhaps due in part to the height and consequent exposure of this tree and to the fact that only one hour of observation was possible. Nevertheless, the total usage by families was in accord with the pattern that prevailed at Karimui, namely a predominance of honeyeaters (79 per cent), followed by lorikeets (20 per cent ) and a very small remainder ( 1 per cent ) . FEEDING ASSEMBLAGES IN FRUITING TREES Most of the fruiting trees in which we found feeding birds could readily be placed in one of two categories: Those that bore small (< 5 mm) fleshy fruits and attracted a large variety of bird species, and those which bore larger ( > 10 mm) fleshy fruits that were evidently unmanageable for small birds. Small fruits. — We shall first consider trees with small fleshy fruits, in particular a set of three large strangling figs. These appeared, on examination of their fruits and foliage, to be of the same species, though possibly they were closely related species. All were of great stature (at least 100 feet), had broadly spreading crowns, and were heavily laden with soft pinkish fruits 4—6 mm in diameter. At Sordida (3,650 feet) one of these stood alone in an area that had been recently cleared for native gardens. The clearing was surrounded on all sides by forest which came to within 35 yards of the strangler. Another of these trees was located in dense forest at 3,500 feet in the bottom of a ravine about 14 miles southeast of Okapa Patrol Post. The third fruiting strangler was in montane forest at 5,800 feet near the Lore village of Miarassa. The results of five, three and four observation periods at these three trees, respectively, are given in Table 4. The number of species that regularly fed in the stranglers was only slightly greater on the average than in the Karimui white-flowered trees, but included a notably greater variety of Tcrborpli and Diamond NEW GUINEA EEEDING ASSEMBLAGES 37 families. Whereas each of the white-flowered trees at Kariinui attracted eight to ten species of honeyeaters, none of the stranglers was used hy more than three species of any family. Pigeons and honeyeaters were numerically dominant and accounted for 52-79 per cent of the total usage. Members of ten other families comprised the substantial remainder, again in contrast with the flowering trees in which the two principal families, honeyeaters and parrots, accounted for 91-99 per cent of the usage. In consequence of the marked altitudinal turnover of bird faunas in New Guinea, the bird assemblages found in the three stranglers had very few species in common. The Sordida and Okassa trees shared only four out of a total of 25; the Sordida and Miarassa trees may have had one common species of Meliphaga out of 24, and the Okassa and Miarassa assemblages shared five out of 19. Members of four families occurred in all three of the stranglers and members of five more used two of them. In view of the great differences in habitat at each of the sites, such consistency implies that the pattern of usage of a given food source is to some measure independent of elevation and the particular species involved. Some of the obvious differences in the data from the three stranglers can probably be ascribed to site-specific factors. The relative scarcity of honey- eaters in the Sordida tree and the abundance of Mino (lumontii, a bird of second growth and edges, are surely due to its exposed position in a native garden. Low numbers of both species and individuals were recorded for the Miarassa tree, not as a result of low usage, but of exceptionally poor visibility of the crown from the only suitable viewing station. Two additional species of trees with small (3—5 mm) fruits were the subjects of less intensive observations (Table 4). One was located in tall forest near Udo in the Karimui region and the other in old second growth near the Gimi Village of Mengino I on the west slope of Mt. Michael. The bird assemblages in these trees differed from those in the stranglers in at- tracting smaller numbers of species and families and in the preponderance of honeyeater usage. Since the results are based on only one and three hours of observation, respectively, the species lists are unrealistically low. Nevertheless, the scarcity (absence) of parrots, and the presence of pigeons, cuckoo-shrikes, whistlers, and flowerpeckers, is similar to the pattern found in the stranglers and quite unlike that of any of the flowering trees. Large fruils. — Larger fruits were consumed almost exclusively hy pigeons. Typical results are given in Table 4. The two trees held heavy crops of soft olive-sized fruits and in both the feeding was confined to two species of pigeons. In contrast with the sustained use of trees hearing flowers or small fruits, the presence of birds at sources of large fruits was sporadic and un- predictable. The trees were generally vacant for most of the day and when 38 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 a group of pigeons did arrive, it seldom remained for as long as an hour. Most of the flocks of feeding pigeons that came to the observer’s attention contained a single species only. The large parrots and hornbills that might be expected to feed on large fruits in company with pigeons were never seen to do so. The population densities of these birds in the localities we visited were, however, low, and the large parrots are generally shy. Ficus fruits. — An intriguing exception to the usual absence of passerine birds from trees with large fruits was uncovered in the case of three trees of a Ficus species (Table 4) . Two were in tall forest along the Udo road near Karimui, while the third was in a grove of Casuariria second growth at an elevation of 5,800 feet near Miarassa. The fruits were ovoid-cylindrical, 6-8 cm in length and 3-4 cm in diameter. A thick woody pericarp precluded any direct assault on the sweet seedy pulp within. Nevertheless, examination of fallen fruits indicated that most had been entered by neatly cut holes, about 1 cm in diameter, in the blossom ends. Observation of the feeding birds soon disclosed that the holes were made by lorikeets. Tossing chips aside with a shake of the head, they gained access to the pulp within 5 minutes. Apparently, the side walls of the pericarp were invulnerable even to the lorikeets, because they always abandoned the fruits with most of the pulp remaining. The preopened fruits then attracted many other species, principally honeyeaters whose long and delicate bills are well-suited for probing but quite incapable of opening these fruits. The second Udo Ficus (Table 4) was observed at an early stage in ripening when it held an abundance of unopened fruits which attracted lorikeets (> 99 per cent of usage), but before it contained sufficient numbers of opened fruits to be of interest to other birds. The first Udo tree and the Miarassa tree were at a later stage by which parrot usage had declined to only 8 per cent and 6 per cent, respectively, of the total. Honeyeater usage, on the other hand, had mounted to 90 per cent and 93 per cent. A clear example of the dependence of feeding capabilities on bill structure, this extraordinary situation produced a pattern of tree usage reminiscent of both flowering and fruiting trees. The absence of pigeons and 95-100 per cent usage by parrots and honeyeaters are suggestive of the former, while the presence of cuckoo-shrikes, whistlers, and flowerpeckers is typical of the latter. Bark feeding. — While at Karimui we encountered an active feeding tree whose attraction was apparently either a sap exudate or excrescences on the bark produced by an infestation. The several bands of parrots that were using this tree restricted their attentions to the smooth pale gray bark of the upper trunk and main branches (Table 4). All four species appeared to use the same method of feeding which consisted of slowly working up or down Terborjili and Diamond NEW GUINEA EEEDING ASSEMBLAGES 39 o D -D O “O r- C/D QJ W H-1 CQ < o H < z Is] CJ a; CO C/D < C/) •-« a O U] :£ Q, O z 3 a :s] o C/D ^ P 5 C/D D cb O be II o :: 1- (1> V5 bfi.ti g o«IM snojj i^ssiEiinjv; CO ^nof^ opQ pLiooas snjfj opn CO aaj) Hpip.ios aaj; i3ssvj>io aaj) 4ynjj opf^ ^ aUTA Supuuj OLnSiiaj^ co iaiSuB.i:is BSSHJBij/V t}< .ia|SuBj;s t^ssB>io CO .Ta{SuBi;s ijpipios lo sjaAVO|^ snasTqifH 99j; SuiiaMOjj BU9§ pa.TaMO{j“.iapu9ABq S99.T4 00 p9jaA\0[j-a;iqyv\. X! O D O K CO <00> U- C 40 S a (Ti 40 c ‘k: Qj ^ pi 40 . ^ r\ i, u g ^ t-O 5 ■ Sf s. « c/5 C S 60 Q-, c: ^ ®- ~2 2 5 ^ Cj o 6/j Cl. o CS) (-H \0 VO o I"- C\ On CO CO CO CO V <0) CM CM '--I O CM VO CO CO k. bX) cd a. Trichoglossus haematodus Domicella lory Charmosyna pulchella & piacentis placentis Table 4 (Continued) 40 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 o 3 5^ V-4 I^H .S/IJljJ BSSB.lV;iJ\[ CO Opn. pUOD^S snjij^ opn is.uj[ CO 99.14 4?pIp.IOS 99.14 4injJ BSSB5JQ 99.14 4121.14 OpQ rH 9 LIT A. SupTii.ij ouiguajA^ CO J94§UB.qS .I9|§UB.I4S BSSt35fO ^ a94gUl?.I4S ■BpTp.IOS 10 S.I9A\044 SIIDSTCPH 99.14 Sul.t9AS.04J T3U9S •l^Aiy[ p9J9A\04J-.19pU9A13T S99J4 GO p919AS04J-94U4yVV ^ as > 3; CO O UO CO CO CNJ 04 CN ^ csj (M V csi o o cs o V r— I V r— i V V CD 05 Si o c cx o ^5JD o o is o QJ o iJ cx o o o iS L.. o CD QJ CO ^ i; S k. o o CD 0 is CD c CO cx 0 0 k) 0 cx t>JD 0 0 k. 0 S is 0 io ^ aaj; pnaj opn. 8UIA SupIlUJ OUTgU9IN[ ^ a9[§ui?-qs BSS13.It!Tp^ T}^ a9]^SuBj;s i3SSu:>io ^ J9|§uiu;s t^pip.ios lo S.T9M0|P snosiqifp nH y: z o 99.TP §Ur.I9M0|J i?u9s ^ S9UtA p9a9A\0]p-.I9pU9A'Bq S99JJ CXD pD9.I9A\O{J-04iq^ V V CM \o o CO CO c-o rO oo cO CO Csj ^ ^ V V !>, I— I Cm V V f-H V Table 4 (Continued) 42 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 CQ 0 0 c/5 bC-tJ =3 £ Of OBIV STU/J BSSB.ll3IJ\ CO moij^ pLiooas snotg^ opfi 4S.ii^ CO aaj; Ijojj Bpip-iog aai4 lyiTjj «ssB>{o 9aj4 4]iT.ij opj^ 9UtA Sinjiruj OLiiSuaj/^ co Ja^SuBUS ja^SuBJ^s Bpipiog ^ sjaA\0{_j snosiqiH aaj) §uuaA\ojj Buag JaAivi ' pajaA\0[j-japuaABq[ saaJ4 QQ pajaA\o(j-a4iHyw o X I— I ^ V (N V V r< o o ^ s- s O O, V (N G^ c:^ 0\ CO i^ C4 CO CO CO CO csi O CSI r- 04 CO 'O o CO CO CO CM CO I-H |> CM On CO ^ V CO CO r-H o 1— I CM ‘O) V lO G^ t— ! I-H CO CO o V =3 CJ -5 S Cr S' OjO CO ‘::2 o a 2 ^ "-S S ex ^ Sc o c o •-i 0.) !S C O goo S o i:: ^ £ C3 (0 0ajp 4injj opQ 0UTA Suipimj ouiguajAi ^ J0[§UIU;S BSSIUBIJ^ ^ I0[§UBJ4S BSSB>(0 ' j0[SuuJ4s Hpoipiog SJ0As.og snosiqiH 09Jp SUU9A\0[P BU9S laAI^ p9J9A\0[p-J9pll9AT3'q ^ S99J4 00 p9J9A\0[^-9;iqAV ^ 0) Vi Si O CO O V V o ^ I- cq c4 o o C<1 CO CO CO o C o o o a^ CO CO o c^ crj (N 04 ^ O CO O --H CO csi V fN Os CO o o o o CO r-H l>- o i-H csi V ^ Cr\ cq f— ! LO LO CO rH CO o^ r- csi u- cvq oq o CO CO o r— I nH LO vv ^ CJ a; Oh V/ V5 CD ^ ?3 B 5 § ra f-* 3 ^ cs -H ¥ ^ S^ ;:s •S o CO a Qj «o O c: tUD ^ .5- § CL O 5h br in ^ -1^ C QJ ^ Oh ^ i-i C c Cj CD "O 0) t) o c: k. 1) G a> CO o CJ> IS N *S CD D O ffi CD . (D *o ermanent population. That large concentrations of these ducks still do winter on some of the southern lakes is indicated by the record of at least 1,000 seen on a lake between Abualuco and San Juanito, Jalisco, 21 and 22 January 1968, by Lytle Blankenship (pers. comm.). It would seem that so many birds must have congregated from a rather extensive breeding area, thereby supporting the idea of partial migra- tion (Johnsgard, 1961a). Localities, dates, and numbers of Mexican Ducks ol)served and collected by the authors in 1966 were: Lago Babicora, Chihuahua, small pond, 7 May, 2 (1 pair) ; Ciudad Guerrero, Chihuahua, small pond, 7 May, 4 (1 pair) ; Julimes, Chihuahua, Conchos River, 9 May, 6 (3 pairs) ; Julimes, Chihuahua, Conchos River, 27 May, 1 duck l2 nests with eggs found between 9 and 27 May reported to us) ; Boquilla, Chihuahua, Conchos River, 10 May, 6 (3 pairs); Parral, Chihuahua, lake south of town, 11 May, 1 duck; Ciudad Durango, Durango, lake 20 mi. north of city, 11 and 12 May, 4 (2 pairs) ; Ciudad Durango, Durango, lake 40 mi. southeast of city, 12 May, 6 (3 pairs) ; Jalisco, small lake 30 mi. south of Ciudad Aguascalientes, 13 May, 6 (3 pairs), 1 duck collected; Jalisco, small lake 30 mi. south of Ciudad Aguascalientes, 14 May, 15 ducks, 2 collected; Jalisco, small lake 30 mi. south of Ciudad Aguascalientes, 25 May, 12 (6 pairs), 1 duck collected; Jalisco, 3 small ponds 23 mi. south of Ciudad Aguascalientes, 25 May, 6 (3 pairs), 2 ducks collected; Jalisco, 3 small ponds 20 mi. southwest of Ciudad Aguascalientes, 25 May, 25 ducks, 3 collected; Jalisco, pond 50 mi. south of Ciudad Aguascalientes. 15 Alilricli and Baer MEXICAN DUCK STATUS 67 May, 2 (1 pair) ; Ciudad Tlaxcala, Tlaxcala, lake east of city, 19 May, 7 (3 pairs) ; Ciudad Tlaxcala, lake east of city, 18 May, 6 (3 pairs) ; Chapala, Jalisco, 6 mi. norlli- west, small pond, 23 May, 8 (4 pairs), 1 duck collected; Chapala, Jalisco, 6 mi. northwest, small pond, 24 May, 16 ducks; Las Delicias, Chihuahua, large lake, 28 May, 2 (1 pair) ; Las Delicias, Chihuahua, large lake, 29 May, 2 (lone),.l collected; Las Delicias, Chi- huahua, canal, 29 May, 17 (1 hen with 4 ducklings), 1 adult collected. Localities in northern Jalisco south of Ciudad Aguascalientes and along the Rio Conehos and its tributaries in east-central Chihuahua were the most productive of records. The two nests with eggs found between 9 and 27 May at Julimes, Chihuahua, were reported to us by Senor Manuel Ramirez, former mayor of the town, whose observations were known by Baer to be reliable. The brood at Las Delicias, Chihuahua was found by Baer. These were the only places where we had definite evidence of Mexican Ducks nesting. In fact, in most other places, the occurrence of both members of the pair together at all hours of the day, and the incompletely developed gonads of specimens collected indicated that nesting had not started. It may he that nesting is delayed, as suggested by both Allan Phillips and Robert Dickerman ( pers. comm.) , until the beginning of the summer rains. Exceptions to this are especially favorable localities such as we noted along rivers and canals with a permanent and copious flow of water. The beginning of egg laying by captive Mexican Ducks in early April at the Bosque del Apache Refuge, New Mexico, where water is supplied artifically, hut summer rains do not normally come until June or July, tends to support this theory. Although there are a few records of April and May nesting in New Mexico (Lindsey, 1946) , initiation of egg-laying for the most part, both in that area and further south, appears from records of eggs and downy young to be after the first of June. In all, 120 Mexican Ducks were seen in 14 of the 43 likely areas inspected in Mexico between 6 and 29 May 1966. Of these, 12 (7 males and 5 females ) were collected. This seems like a very small and scattered population con- sidering the distance traveled and special efforts to find these birds. This, together with the shortage of water in general and the disturbance of habitat by people and livestock almost everywhere, indicates that the survival of this species may be endangered. MORPHOLOGICAL VARIATION Viewed in series and individually from above, male Mexican Duck speci- mens of all seasonal and geographic groups showed a more pearly -gray wash on the tertials than females. Below, males showed a generally darker appear- ance, particularly on the chest, which was also more reddish brown. Several 68 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 males from New Mexico and Chihuahua showed traces of Mallard c acteristics. This took the form of varying amounts of green on the head anc vermiculation on the dorsal plumage. The presence of varying amounts of bright yellow on the brlls of four males and one female from New Mexico and northern Chihuahua is not understood. No specimen from the southern part of the range of Anas diazi showed this characteristic and only one out of many specimens of Anas platyrhynchos examined, a male from the State of Washington, showed a similar condition. Breeding specimens (late April through August) differed from those taken at most other times of the year only in appearing slightly more worn in most birds. However, September specimens were the most worn of all. Specimens of both sexes from south of Chihuahua, generally referred to as Anas diazi diazi (American Ornithologists’ Union, 195/; and Lriedmann, Griscom and Moore, 19.50) appeared very similar to birds from Chihuahua northward, generally considered as representing A. d. noviniexicana. Viewed itr series, the southern specimerrs averaged very slightly darker and more brownish, less grayish, with feather edgings more rufescent, and less huffy below. This was due to an average darker color of light huffy portions of the feathers of the underparts and more heavy streaking of brown. When only specimens taken during the arbitrarily designated breeding season were in- cluded, the series was less variable and the differences between northern and southern groups slightly more pronounced. The differences were more pro- nounced in the males in which southern specimens were darker particularly on the posterior underparts and had less reddish brown chests. Pitelka ( 19T8 ) noted similar differences in specimens available to him which were also used in the present study. As Pitelka pointed out, the irregular wavy barring of fulvous on the mantle, mentioned as a character of a northern form by previous investigators, is found in certain individuals in all populations and is of no taxonomic significance. An effort was made to exclude all specimens which showed indication of hybridization with the Mallard from the series used for study of geographic variation. However, there is a possibility that the more grayish and paler coloration noted in the northern group resulted from infiltration of Mallard genes without resulting in obvious Mallard characteristics. In any case, the average color differences between northern and southern populations are too slight and individual differences in each series too great to permit identification of single birds as of northern or southern type. Lurthermore, there appears to be virtually no difference in size, indicated by the followino^ measurements, which would be of use in distinguishing these populations. Aldricli and Hae?' MEXICAN DUCK STATUS 69 Northern specimens, A. d. novimexicana (?), all seasons Adult Male (18 specimens): Wing, 260-289 (273.9) mm; tail, 75.4-90.7 (85.1); ex- posed culmen, 50.4^56.4 (53.0) ; tarsus, 40.1-47.4 (44.2) ; mid-toe without claw, 47.8-58.2 (52.0). Adult Female (27 specimens): Wing, 237-271 (254.7) mm; tail, 68.1-88.6 (81.7); exposed culmen, 47.1-55.1 (51.0) ; tarsus, 38.3-49.3 (42.6) ; mid-toe without claw, 46.7- 58.4 (51.7). Southern specimens, A. d. diazi (?), all seasons Adult Male (13 specimens) : Wing, 260-282 (269.9) mm; tail, 76.0-95.0 (86.3) ; exposed culmen, 51.1-55.6 (53.3) ; tarsus, 43.1-48.4 (46.3) ; mid-toe without claw, 51.4- 57.7 (.53.7). Adult Female (13 specimens) : Wing, 232-268 (253.4) mm; tail, 80.0-89.5 (85.1) ; exposed culmen. 45.5-52.7 (50.3) ; tarsus 40.2-43.6 (42.0) ; mid-toe without claw, 47.3- 53.1 (49.8). Northern specimens, A. d. novimexicana, breeding season Adult Male (5 specimens) : Wing, 272-289 (278.4) mm; tail, 78.1-90.4 (84.1) ; exposed culmen, 51.6-56.4 (53.5) ; tarsus, 42.2-47.4 (45.0) ; mid-toe without claw, 50.3- 54.1 (52.1). Adult Female (13 specimens) : Wing, 242-271 (254.4) mm; tail, 77.2-88.6 (82.6) ; exposed culmen, 47.1-55.1 (50.7) ; tarsus, 38.3-49.3 (42.8) ; mid-toe without claw, 46.7- 58.4 (52.2). Southern specimens, A. d. diazi, breeding season Adult Male (10 specimens): Wing, 260-282 (269.1) mm; tail, 76.0-95.0 (86.0); exposed culmen, 51.1-55.6 (53.2); tarsus, 43.1-48.1 (46.0); mid-toe without claw, 51.4- 55.1 (53.2). Adult Female (13 specimens) : Wing, 232-268 (253.4) mm; tail, 80.0-89.5 (85.1) ; exposed culmen, 45.5-52.7 (50.3); tarsus, 40.2-43.6 (42.0); mid-toe without claw, 47.3- 53.1 (49.8). In view of the lack of difference in either color or size that would make it possible to identify reliably a specimen as representing either northern or southern populations, we conclude that the “New Mexican Duck,” Anas diazi novimexicana, is not a valid subspecies and that the Mexican Duck is a monotypic species. RELATIONSHIP TO THE MALLARD The large number of specimens in collections which show morphological evidence of mixture of genes of Anas diazi and Anas platyrhynchos raises a question as to the specific relationship of the two. Lindsey (1946) and William Huey (pers. comm. ) give evidence that individuals with mixed char- acteristics may be of fairly common occurrence. Lindsey noted that hybrids, usually outnumber the pure Mexican Ducks wintering in Rio Grande Park, Albuquerque, New Mexico. Huey considers this situation abnormal because those ponds, which were associated with the Albuquerque Zoo, usually con- tained a mixture of domestic mallard-type birds. He says that among ducks trapped for banding at the State refuge at Radium Springs, New Mexico,. 70 THE WILSON BULLETIN Marcii 1970 Vol. 82, No. 1 ratios of what were considered pure bred to hybiids weie. US), 20/6, 1960, 15/11; and 1961, 23/11. There is no way of relating these figures to the proportion of hybrids to purehreds of either Mexican Ducks or Mallards in any given breeding population. Opinions of systematists differ on how to handle this situation in the nomenclature. Nomenclatural treatments, such as Peters (1931), Hellmayi and Conover (1948), Lriedmann, Griscom, and Moore ( 1950), and Ameiican Ornithologists’ Union (1957), accord Mallards and Mexican Ducks distinct species rank while Delacour (1956), A. Phillips (1959, 1961), and Johnsgaid (1961a, b) consider them conspecific. The difference of opinion is piohably largely the result of differences in concept of what constitutes a species. The mere fact that hybridization occurs, of course, is not enough to deny specific rank. Practically all species of ducks will hybridize, especially if mates of their own species are unavailable. This happens frequently in captivity hut rarely in the wild. The criterion we are following is that two populations are considered as distinct species if they do not ordinarily interbreed when they come together in the wild. It would appear that the Mexican Duck and the Mallard do interbreed when they come together in the wild, but there is still a question of the extent to which this occurs — whether it is the rule or the exception. Unfortunately, both Mexican Ducks and Mallards are so rare where they occur together during the breeding season that it is difficult to determine the incidence of their interbreeding. This rarity in itself results in a shortage of mates of the same type and is thus conducive to crossing with one of the other type. There is no doubt that we have here a borderline situation between species and racial status. It seems likely that the sexually monomorphic Mexican Duck, like the Black Duck {Anm rubripes) differentiated from the wide-ranging dimorphic common Mallard in the past as a result of ecological or distance harriers to gene flow and different sets of selection factors as postulated by Johnsgard ( 1961a) . In more recent times, this reproductive isolation appears to he breaking down, possibly due to man-induced habitat changes. As a result of these secondary junctions, hybridization of both Mexican and Black Ducks with Mallards is taking place. Whether this process progresses to the complete genetic amalgamation of the overlapping populations depends on the extent to which reproductive barriers have evolved during the periods of isolation. In the case of the Mexican Duck, factors possibly inhibiting, if not actually preventing crossing with Mallards, might be their lack of sexual dimorphism which would guide the female in choosing a mate of her own kind, different nesting habitat requirements, different climatic tolerance and different timing of reijroductive condition based on rainfall cycles. Mallard and Mexican Ducks resemble one another chiefly in female plumage, hut even in this there Aldrich and Baer MEXICAN DUCK STATUS 71 are some rather distinct differences as indicated in detail by Huey (1961). In assessing the species relationships of North American mallard-like ducks, Johnsgard (1961a), after detailed analytical studies, concluded that none of the described plumage or soft part characters, aside from sexual dimorphism of platyrhychos, were of absolute diagnostic value. Our much less detailed studies of plumage and soft parts agreed with his findings. Johnsgard noted that experimental breeding had shown that the genetic basis for sexual di- morphism in the Mallard is relatively simple and not sufficient to be con- sidered as a basis for a species difference. No qualitative, only quantitative, differences were noted in courtship displays between Black Ducks and Mallards. This quantitative difference in behavior of Black Duck was thought possibly to compensate for lack of sexual plumage differentiation in mate selection. However, courting groups of the species normally remained almost completely segregated and hybrids tended to court with groups they most closely resembled. No observations of sexual behavior of Mexican Ducks were obtained but JohnsgarcTs notes on the Black Duck and Mallard are strongly reminiscent of Huber’s (1923) observation that while flocking in winter and early spring, Mexican Ducks stayed together and did not mix with Mallards. Johnsgard (1963:538) concluded that it appears that isolating mechanisms in Anas are based primarily on male plumage or soft part features and associated courtship displays that exhibit these features. Still later, Johnsgard (1967:61) found that obvious Mallard X Black Duck hybrids rarely exceed more than 2 per cent of combined populations indicating that assertive mating is operating effectively. Although similar data are unavail- able for the incidence of Mallard X Mexican Duck hybrids, if the assertive mating is due largely to the great difference in plumage pattern and color of the males, one might expect a similar incidence of mating inhibition between Mexican Ducks and Mallards as between Black Ducks and Mallards. Only time and further study will show to what extent speciation has progressed in the case of the Mexican Duck. However, until it is demon- strated that the sexually monomorphic diazi and dimorphic platyrhynchos populations are freely interbreeding, and ducks of hybrid type definitely out- number examples of apparently pure strains in breeding areas in the zone of contact, it would seem advisable to follow the concept of two distinct but closely related species. Anas diazi and Anas platyrhynchos. This concept would seem to agree with that of the semi-species as elucidated by Short (1969 1 who also thought these units should he considered taxonomically as species. SUMMARY 1. Currently recognized northern and southern subspecies of the Mexican Duck are not based on sufficiently distinct or consistent size or color characters to he maintained. Therefore, the species is considered nionotypic. 72 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 2. Although a borderline case in species distinctness, the Mexican Duck (Anas diuzi) appears to have a certain amount of reproductive isolation fiom the Mallaid (Anas platyrhynchos) in areas of sympatry. Tlierefore, it is considered as taxonomically a distinct species. 3. The Mexican Duck has virtually the same overall geographic distribution now as formerly which is southeastern Arizona, the Rio Grande Valley of New Mexico, and cential- western Texas southward through the central highlands of Mexico to the Tians-Mexican Volcanic Belt south of Mexico City. However, it has disappeared as a breeding bird from much of this extensive area because of the drying up of its habitat. The trend of decline of the Mexican Duck and its breeding habitat, both in Mexico and the United States, indicates that it is probably in danger of extinction. ACKNOWLEDGMENTS We wish to acknowledge the loan of critical specimens and making available data on other specimens to Dr. Walter J. Breckenridge, James Ford Bell Museum of Natural History, University of Minnesota; Dr. Dean Amadon, American Museum of Natural History; the late Dr. Alden H. Miller, Museum of Vertebrate Zoology, University of California, Berkeley; Dr. Raymond A. Paynter, Museum of Comparative Zoology, Harvard; Dr. John W. Hardy, Occidental College; and Mr. James Bond, Academy of Natural Sciences, Philadelphia. For information and many courtesies in the field, we are indebted to Dr. Allan R. Phillips, University of Mexico, Mexico City; Dr. Rodolfo Hernandez Corzo, Director General de Caza, Direction General de la Fauna Silvestre, and staff, Mexico City; Capitan David Alatorre T, Chief of Game for the same agency in Juarez, Chihuahua; Karl F. Uueder, Chapala, Jalisco; the late Sehor Jesus A. Terrazas, sportsman of Ciudad Chihuahua; Senor Manuel Ramirez, of Julimes, Chi- huahua, Senores Valentin and Rufino Padilla, of Ciudad Aguascalientes; James and Seymour Levy of Tucson, Arizona; Erwin L. Boeker, E. G. Wellein, Mitchell G. Sheldon, Charles Heumier, Lytle H. Blankenship, George B. Saunders, Roy E. Tomlinson, and Gail Monson, Bureau of Sport Fisheries and Wildlife. We wish to express our apprecia- tion particularly to Mr. William S. Huey, New Mexico Department of Game and Fish, and Dr. Robert W. Dickerman, formerly of Oficina Sanitaria Panamericana, Mexico City, now of the Department of Microbiology, Cornell University Medical College, New York, New York, not only for advice and assistance in the field and permission to use their unpublished data, but also for suggestions in the preparation of this paper. LITERATURE CITED American Ornithologists’ Union. 1957. Check-list of North American birds. Ameri- can Ornithologists’ Union. Bent, A. C. 1923. Life histories of North American wild fowl, order Anseres (Part). U.S. Natl. Mus. Bull. 126:1-250. Delacour, J. 1956. Waterfowl of the world. Vol. 2, The dabbling ducks. Country Life Ltd., London. Dickerman, R. W. 1%3. The Song Sparrows of the Mexican Plateau. Occ. Papers Minnesota Mus. Nat. Hist. No. 9. Friedmann, H., L. Griscom, and R. T. Moore. 1950. Distributional cbeck-list of the birds of Mexico, Part 1. Pacific Coast Avifauna 29:1-202. Goldman, E. A. 1951. Biological investigations in Mexico. Smithsonian Misc. Coll. 115:1-476. Aldrich and Baer MEXICAN DUCK STATUS 73 Hellmayr, C. E. and B. Conover. 1948. Catalogue of birds of the Americas. V(j1. XIII, Pt. 1. No. 2:1-434. Huber, W. 1923. (in Bent, A. C., Life Histories of North American wild fowl) U..S. Natl. Mus. Bull. 126, pp. 48-50. Huey, W. S. 1961. Comparison of female Mallard with female New Mexican Duck. Auk, 78:428-431. International Union for Conservation of Nature and Natural Resources. 1966. Red Data Book, Vol. 2, Aves. Compiled hy Jack Vincent, Survival Service Com- mission, Morges, Switzerland. JoiiNSGARD, P. A. 1961(7. Evolutionary relationships among the North American mallards. Auk, 78:3-43. JoHNSGARD, P. A. 19616. (Letter to the editor) Auk, 78:672-674. JoiiNSGARD, P. A. 1963. Behavioral isolating mechanisms in the family Anatidae. Proc. XHI The Internatl. Ornithol. Congr. pp. 531-543. JoiiNSGARD, P. A. 1967. Sympatry changes and hybridization incidence in Mallard and Black Ducks. Amer. Midi. Nat., 77:51-63. Leopold, A. S. 1959. Wildlife of Mexico. Univ. of California Press, Berkeley. Lindsey, A. A. 1946. The nesting of the New Mexican Duck. Auk, 63:483-492. Peters, J. L. 1931. Check-list of birds of the world. Vol. 1. Phillips, A. R. 1959. The nature of avian species. J. Arizona Acad. Sci., 1:22-30. Phillips, A. R. 1961. (Letter to the Editor) Auk, 78:670-672. Phillips, J. C. 1923. A natural history of the ducks, Vol. H. Houghton Mifflin Co., Boston & New York. PiTELKA, F. A. 1948. Notes on the distribution and taxonomy of Mexican game birds. Condor, 50:113-123. Short, L. L. 1969. Taxonomic aspects of avian hybridization. Auk, 86:84—105. U.S. Bureau of Sport Fisheries and Wildlife. 1966. Rare and endangered fish and wildlife of the United States. Compiled hy Committee on Rare and Endangered Species. Resource Publication 34. BUREAU OF SPORT FISHERIES AND WILDLIFE, U.S. DEPARTMENT OF INTERIOR, WASHINGTON, D.C., 17 JUNE 1968. PARASITISM BY THE BROWN-HEADED COWBIRD ON A BROWN THRASHER AND A CATBIRD Robert M. Mengel and Marion Anne Jenkinson Despite the accumulation of an impressive body of information (sum- marized by Friedmann, 1929, 1963 ) on the breeding biology and social parasitism of the Brown-headed Cowbird {Molothrus ater), most of the evidence concerning the cowbird’s activities at the nests of its hosts remains circumstantial, and reports of direct observations of these activities are remarkably few. Even in some of these instances it is difficult to interpret the evidence and one often wishes that more details had been given. In view of this, and following the example of Mayfield (1960:164-171), we here- with report our observations (all 1965) of parasitism by a cowbird on a Brown Thrasher (Toxostoina rufitni) in some detail. Incidentally we have included some brief notes on a parasitized nest of a Catbird [Dumetella carolinensis) . OBSERVATIONS AT THE THRASHER NEST 4 May. — A pair of Brown Thrashers completed their nest. It was four feet up and well concealed at the east end of a dense climhing rose which extends 20 feet along the south side of a redwood board fence, just north of our home in Lawrence, Douglas County, Kansas. 5 and 6 May. — No observations. 7 May. — Very early in the morning we caught the female Brown Thrasher in our mist net. We do not know if she had been to the nest earlier that morning to lay an egg. .She was badly entangled and we disentangled her with some difficulty. We handed and released her (USFWS 623-40000 and red color band). However, after she had flown some 15 feet, she dropped to the ground and we realized that she had probably sprained her wing. Because of this we watched her closely for the next several hours and were aware at all times of her location and condition. Through this period her mate closely attended her. Neither of the thrashers returned to the vicinity of the nest until late afternoon. At 11:00 we checked the nest. It contained one egg of the Brown Thrasher and one of a Brown-headed Cowbird. At 12:32 a male and female cowbird flew in from the north and alighted on the fence, about 10 feet east of the thrasher nest and about 2 feet apart, the female being nearer the nest. After remaining thus for about two minutes, the female started edging towards the rose. She was followed by the male who precisely maintained their original distance of separation. The female’s actions seemed entirely purposive — she seemed to know of the nest. She disappeared into the cover of the rose near the nest site. The male w'aited on the fence, facing north, just east of the rose. After about two minutes he flew off to the north. We did not see the female depart and thought she was still at the nest. At about 12:40, a male and female cowbird appeared from the north and landed in a nearby tree. The male remained there, hut the female flew to the fence top, just west of the rose, and immediately disappeared into the cover of the rose. In about 30 74 Mengcl and Jenkinson COWBIRD PARASITISM ON BROWN THRASHER 75 seconds, an empty-billed female cowbird emerged abruptly from the area of the nest, chattering sharply, and flew rapidly to the east. She was followed immediately by the male. Since we had seen “two” females arrive and only “one” leave, we assumed that one was still on the nest. Thus we waited eight minutes Irefore investigating. When we did, we found that no cowbird was at the nest and that the nest now contained only one egg — that of the thrasher. A short search revealed the fragmented shell of the still fresh cowbird egg, parts lying a few inches on either side of the fence, beneath the nest. The horizontal boards of this fence are so lapped that an egg could easily be dropped through one of the interstices. It seems highly probable that the “first” female had departed unseen through one of these openings, dropping the egg en route and being followed by the male. ( This route later became the favorite one of the thrashers as they entered and left the nest area.) 8 May. — At 08:30 a female cowbird was seen percbed about 10 feet west of the rose looking intently in the direction of the nest. The male thrasher was perched just west of the rose, erect and watchful; after a few minutes the cowbird flew away to the east. We immediately checked the nest, flushing the female which apparently had begun to incubate, and found another cowbird egg, but only one thrasher egg rather than the two we had expected. The female thrasher seemed to be fully recovered from her injury of the day before. At 12:32 (almost exactly 24 hours after the visit of the day before) a female cowbird appeared alone on the fence a few feet west of the rose. Again, seeming quite purposive, she entered the cover and was out of sight just the requisite time to reach the nest. She then emerged with conspicuous abruptness and departed hastily eastwards, having discovered the female thrasher on the nest. 9 May. — Morning and evening checks of the nest revealed its contents unchanged. A thrasher flushed from the nest at 09:00, but the birds seemed somewhat less attentive than they had on 8 May, and none was on the nest at the evening check. At 18:48, a female cowbird appeared on the fence about 2.5 feet east of the rose. She took con- siderable time going to the rose but seemed entirely purposive. After a short time at the nest (as indicated by agitation of the surrounding vegetation) she departed to the north. The contents of the nest remained the same as before, i.e., one cowbird egg and one thrasher egg. 10 May. — At 10:00 the nest now contained two Brown Thrasher eggs and one cow- bird egg. 11 and 12 May. — Situation unchanged. The thrashers seemed very attentive during . these two days and one was flushed at the times of the three checks we could make (both mornings and the first evening). 13 May. — At 11:00 the nest was checked and a thrasher flushed. The nest contained two thrasher eggs but no cowbird egg. An immediate search revealed no trace of the missing cowbird egg, but we did discover an egg of a thrasher, one end embedded in the mud and its .shell nearly intact save for the point of impact, where it was badly smashed. The yolk was hard and dry. It was just south of the fence, at a point previously unsearched, about six feet west of the nest and still within the confines of the rose. Subsequent days. — The male thrasher evidently met with some accident and was not seen after 15 May. The female incubated her remaining two eggs in an increasingly desultory fashion for two more days, being last seen on 18 May. After that date two different thrashers appeared regularly in the yard. On 21 May we took the two abandoned thrasher eggs. They contained moderately advanced embryos. 76 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 OBSERVATIONS AT THE CATBIRD NEST A pair of Catbirds built a nest in a forsythia bush about 25 feet from the site of the Brown Thrasher nest. Three Catbird eggs were laid in the nest, one each on 30 and 31 May, and 1 June, and two Brown-headed Cowbird eggs were laid there, one each on 31 May and 1 June. The female Catbird stayed at the nest much of the time after the appearance of her first egg, although we do not know if she was incubating. A female cowbird appeared near the bush on several occasions but sire always disappeared behind the bush and we were not able to see if she went to the nest or flew directly away. In any event, no eggs were removed from this nest. The female Catbird was apparently incubating the cowbird eggs along with her own when the nest was destroyed by a violent hailstorm in the early evening of 1 June. Tliese data are presented because there are few records of a Catbird accepting cowbird eggs (see Friedmann, 1963:69-70). Tlie fact that the cowbird did not remove any of the host’s eggs from this nest may result from the very early attendance by the female Catbird to her nest. DISCUSSION Proprietary interest by cowbirds in nests of their hosts. — On the basis of his own observations of Kirtland’s Warblers (Dendroica kirtlandii) and those of various other workers on other species, Mayfield (1961) concluded that cowbirds show a proprietary interest in nests which they have parasitized or are about to parasitize. Our observations strongly support that conclusion. In all, we recorded five visits to the thrasher nest by a female cowbird, ranging from 08:30 to 18:48 and on three days. Although we kept no record of our total observation hours, we spent a very small proportion of our time watch- ing the nest, and the five visits thus suggest a high degree of interest by cowbirds in the nest site. Pair bonds of cowbirds. — Our observations agree with those of Laskey (1950) which suggest that cowbirds form a pair bond and tend to occupy a certain area or “domain” (see pp. 166-167). Our two observations of a male cowbird accompaning a female to the nest site, and of his waiting for her while she went to the nest, seem to be unique. At no time did we see more than one male and one female in the area until 1 June, when a flock of 10 (about equal numbers of males and females) was seen in a neighbor’s yard, about 100 feet from the nests in question. Throughout the period, a male cowbird frequently sang from a television antenna across the street. We are inclined to think, therefore, that we may have been observing the activities of only one pair of cowbirds, in their domain, and that all four eggs may have been those of one female. Time of removal of eggs by a cowbird. — It now seems to be a well estab- lished fact that the female cowbird does not remove an egg at the time she lays, but does so any time from the day before to (rarely ) the day after that event. Our observations support this fact although we were unable to Mengcl anil Jenkinson COWBIRD PARASITISM ON BROWN THRASHER 77 tell whether the cowbird was removing eggs in advance of or after de|josition. The time of day of egg removal on 7 May was approximately 12:30. It is possible that the female which appeared at about that time on the next day also came for that purpose but was frustrated in her attempt by the presence of the female Brown Thrasher. This is somewhat later in the day than that observed by most, but not all, workers (see Norris, 1944, for a summary, and Mayfield, 1960:160) . Discrimination by the cowbird between eggs. — Our evidence clearly indi- cates that a cowbird egg was removed by a cowbird, on 7 May, and it seems very likely that the second cowbird egg was removed by a cowbird also. We know of only a few other reported instances where the suggestion has been made that a cowbird had removed a cowbird egg from a host’s nest. Mayfield (1960:164), in his extensive study, found no evidence that the cow- bird ever made such a mistake at the nest of a Kirtland’s Warbler. However, Hann (1937:204) found that approximately 30 Ovenbird {Seiiirus auro- capillus) eggs and 4 cowbird eggs disappeared “under circumstances which indicated that the Cowbird had taken them.” Laskey (1950:171—172) re- ported the apparent destruction by cowbirds of cowbird eggs in a nest of a Cardinal { Richmondena cardinalis) and one of the Rufous-sided Towhee iPipilo erythrophthalmus) . However, she found that at both nests several cowbirds had been engaged in heated disputes, and she concluded that the destruction of cowbird eggs resulted from the rivalry of two or more females. Erwin E. Klaas (pers. comm.) has evidence (which he plans to publish later ) which suggests that cowbirds have, on occasion, removed their own eggs from nests of the Eastern Phoebe (Sayornis phoebe) . In these instances, however, the cowbird may have had no choice, since it is possible that only cowbird eggs were present. It is possible that a cowbird also removed the cowbird egg which disap- peared from one nest of a parasitized Brown Thrasher reported by Taylor and Goertz (1965). Because the eggs of Kirtland’s Warblers, Ovenbirds, and Brown-headed Cowbirds are all whitish and lightly speckled, Mayfield (1960:164, 1961:165) concluded that the cowbird discriminates on the basis of size. He noted (1961:165): “The mean size of Brown-headed Cowbird eggs in Kirtland’s Warbler nests is 20.9 by 16.5 mm (N = 24) ; of Ovenbird eggs, 20.3 by 15.6 mm (N = 48, Hann, 1937:172); of Kirtland’s Warbler eggs, 18.1 by 13.9 mm (N = 154).” We measured 27 Brown Thrasher eggs (which also are whitish and lightly speckled ) in the University of Kansas collection, these being one each from 27 clutches taken in Johnson and Jackson counties in western Missouri. The eggs are highly variable in size, shape, and color, but they averaged 26.9 mm (range, 24.2-29.6) by 19.8 mm (18.9-21.2). 78 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 Thus, if the size of the egg is important, even in part, in the cowbird s ability to discriminate between eggs, we would expect a rather high percentage of mistakes to be made at Brown Thrasher nests, since in these the cowbird s egg is the smaller egg, the opposite of the situation with neaily all regular hosts. We think this might account for the fact that there are surprisingly few records of parasitism of Brown Thrashers (see Lriedmann, 1963:/!), the evidence regularly being destroyed by the cowbirds themselves. SUMMARY Two Brown-headed Cowbird eggs were laid in a Brown Thrasher nest. A male and female cowbird, which, from the attendance of the former on the latter, seemed likely to have a pair bond, twice visited the nest area. We think this was the female that also showed a high degree of interest in the rrest on other occasions over several days. Both cowbird eggs were eventually removed from the nest, at least one being thrown out by a cowbird. Tire cowbird may discriminate between its own and, at least, similarly colored eggs on the basis of size and would thus he expected to make a high percentage of mistakes at Brown Thrasher nests. Two cowbird eggs were also laid in a Catbird nest and were being incubated by the Catbird until the nest was destroyed by a storm. ACKNOWLEDGMENT We thank Erwin E. Klaas for sharing with us his data on cowbird parasitism of some Eastern Phoebe nests. LITERATURE CITED Eriedmann, H. 1929. The cowbirds. Charles C Thorrras, Springfield, Illinois. Friedmann, H. 1963. Host relations of the parasitic cowbirds. U. S. Natl. Mus., Bull. 233. Hann, H. W. 1937. Life history of the Oven-bird in southern Michigan. Wilson Bull., 49:145-237. Laskey, A. R. 1950. Cowbird behavior. Wilson Bull., 62:157-174. Mayfield, H. F. 1960. The Kirtland’s Warbler. Cranbrook Inst. Sci., Bloomfield Hills, Michigan. Mayfield, H. F. 1961. Vestiges of a proprietary interest in nests by the Brown-headed Cowbird parasitizing the Kirtland’s Warbler. Auk, 78:162-166. Norris, R. T. 1944. Notes on a cowbird parasitizing a Song Sparrow. Wilson Bulk, 56:129-132. Taylor, W. K., and J. W. Goertz. 1965. Additional records of Brown Thrashers para- sitized by the Brown-headed Cowbird. Wilson Bull., 77:194^195. MUSEUM OF NATURAL HISTORY, THE UNIVERSITY OF KANSAS, LAWRENCE, KANSAS, 29 MAY 1968. HIGH DENSITY OF IHKDS l^KEEDING IN A MODIFIED DEGIDUOUS FOREST David W. Johnston Brekding bird populations in different mature upland deciduous forest communities commoidy vary between 100 and 100 pairs per 100 acres ( Kendeigh, 1061), although drastically altered habitats, such as those fouml in gardens and parks, might sustain as many as 1000 or even 1500 pairs per 1(X) acres ( Pitelka, 1942; table 18.2 in Welty, 1963). For successful breeding in all these terrestrial habitats birds require sufficient foofl and feeding areas, nesting sites, singing perches, a general vegetational aspect, and perhaps other features. Changes in any of these biologic and physical features of the habitat will likely result in alteration of breeding success or population density or both. Turcek (1951), Oelke (1966), and others, for example, have noted that increased stratification of the vegetation in forests will generally result in higher breeding bird densities. The present report considers a breeding bird population study at the University of Virginia Biological Station at Mountain Lake, Virginia be- tween 19—29 June 1967. The Station, located atop Salt Fond Mountain at an elevation of 3800 feet, is surrounded by a second-growth oak-chestnut forest, although the chestnuts are now represented chiefly by sprouts due to blight. Dominant trees in the forest include white oak (Quercus alba), red oak (Q. rubra), cucumber tree (Magnolia acuminata), and black locust (Robinia pseudo-acacia). Mountain-laurel i Kalmia latifolia], blueberry iRaccinium corymbosum), and flame azalea (Azalea calendulacea) are conspicuous shrubby plants. Beginning about 1930 the Station grounds have been parti- ally cleared, and today present a park-like appearance (see photograph in Davis, 1959) because of the open lawns with their borders of preserved or planted mountain-laurel. Rhododendron maximum, blueberry, white ( Finns slrobus) and pitch iP. rigida) pines, hemlock (Tsuga canadensis), and shrubby and herbaceous vegetation. An upperstory or canopy, although somewhat thinned out, consists of white, black, and red oaks, cucumber tree, and pines. The Station grounds differ, therefore, from the surrounding forests by having (1) open lawns, (2) an increase in the shrub layer, (3) thinned-out dominant trees, and (4) numerous (22) buildings that provided some additional nesting sites for Robins and Phoebes. One very small stream traverses a portion of the grounds. In a somewhat arbitrary fashion, we have divided the habitat into strata — ground layer, shrub layer, subcanopy, and canopy — a procedure similar to that of MacArthur and MacArlhur ( 1961 ) in their use of “foliage height profiles.” Also, we have adopted the 79 80 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 stratal limits suggested by Elton and Miller (1954) : ground layer, ft, shrub layer, V2-6 ft; subcanopy, 6-15 ft; canopy, > 15 ft. The only difficulty with these limits in our study lies with the canopy which has a vertical range of 15-60 ft. The breeding bird census was conducted by the author and 10 students on 10 acres that included most of the Station grounds described above. A territory-mapping technique was utilized: territorial limits of all birds on the area were accurately mapped as were occupied nests. Individuals or pairs whose territories were at the edge of and not within the 10-acre plot have been excluded from our totals. Lurthermore, at least 7 additional species (potential breeders) were classified as visitors to the area because they were observed too infrequently to be considered as part of the current breeding population. The results of our census at the Station (Table 1) showed 80 pairs (includ- ing some apparently unmated males) and 22 species on 10 acres (= 800 pairs per 100 acres). These figures differ markedly from those of Chandler (1960) for birds breeding in the deciduous forest neighboring the Station grounds. He found only 16 species and 190 pairs per 100 acres. Of the 22 species occupying territories on the Station grounds in 1967, 11 also hred in the contiguous second-growth hardwood forest and 6 in a forest-edge habitat. The three species with the highest breeding densities at the Station ( Robin, Cedar Waxwing, Least Llycatcher), however, were absent in the nearby forests in 1967 ; neither were they represented in the hardwood forest com- munities studied by Chandler. The most abundant birds reported by Chandler were Ovenbird {Seiurus aurocapillus) , Rose-breasted Grosbeak, and Red-eyed Vireo; of these three, only the Ovenbird had a higher breeding density in the nearby forests than on the Station grounds. At this elevation in the Virginia mountains and considering the generally continuous, unbroken stretches of deciduous forest, it is virtually axiomatic that forest-edge species, such as Indigo Bunting, Slate-colored Junco, Brown Thrasher, and Rufous- sided Towhee, would be restricted to and most abundant at the edge of small clearings or associated with roadside vegetation. The Station grounds ob- viously provided the edge-effects required hy these species. The high density of breeding birds at the Station appears to be attributable to two principal factors. Lirst, as compared with vegetational aspects found in neighboring forests, artificial plantings of rhododendron and hemlock at the Station increased the shrub layer, thus increasing an edge-effect and more nesting sites for certain species. Second, and probably of greater significance than nesting site alone, is the fact that a partial clearing of the forest increased the distance between trees and introduced open spaces both horizontally and vertically, thereby effectively increasing feeding areas for David \V. Johnston DECIDUOUS FOREST BREEDING DENSITY 81 o H ° 5 « o S h S = 2 i: E ^ TJ OJ Z rt -M w hJ S3 o (fi a o Ji — s :: z — s < 5 2 i i ^ > r^OU-'OOLOcOcOCO’^CvJCN|(NCNl^ o CO CO C 'O 3-0 :2 =2 ■' CL ; 3 oi : ^ G 3 O r O c/5 u £2 < < z 2 < 2 2 O 5 c/5 ^ c: <2 CQ o 2 'j2 C/5 =.s c -G o S '5 T^'OU-0*^COCSICO(N’^(N (M CO VO CO CO CO G^ i-H VO Csl (M CvJ CO CO 6" o' 6" in 6" G C/) 1 c/) 1 (T) 1 1 CJ in 1 in 1 1 a 1 CJ 1 CJ in CJ O O CJ O o o o O I CJ CJ UCJOOUCJCJCJ s s ■=: -5 8 r~- =: c “o ^ 5 52 C: S CJ t* ^ •Sf CQ S -2 CO s 03 Q - ^ fx, T3 C -H ^ .i •" ra 03 _S -Q "O CB O OJ Qj c3 DS CJ hJ o s « Cl ^ ^ -c ■5 O 5 a cri — o » y 2 3 S CL, -c cn o c: o 'S, V a 2 ‘2 C3 G 55 ^ a ^ ci S o I 3 ^ O ^ ‘<2 CJ «o c: 05 ex 53 o 2 05 7^ ^ s. ^ 73 OJ 05 05 -Q 05 _ 53 ? ^ Oj :;:n 05 « "JC ^ • 05 c 05 •S o k. o ►o O) ^ O ■*-S r-sS -TX ex C2) s .£ 2 s c: o u o ~o 05 o H -o OJ G S (/) 05 (« ^ :3 -T O 05 k-i c/5 a o Pi pe; C3 'TU 05 "TO 2 e •S 05 8 ex O 05 ^ 5C .i: ^ > ^ C3 05 >> O' o CJ O o Pi (n bC c o § > ” ^ o S bC) 2 'B C --0 ‘=^ V- 2 "2 S to to "X! In. O' a O 05 o 53 C3 k. 0; ex -J ^ 05 05 C/5 k. w 05 05 -O 05 P O f/) •-r? O _C3 C/5 s 73 k C/J P Ph o C S- 4; ° w ^ C/j H -o o '-•— D 53 05 "53 c: 05 Q r« M ^ i c -= S -a ? o o O o n! m ^ m O H to lyj a c r-c: O' 05 3 .3 s 2 2 ^ ^ IX k. ex 53 ^ O ^ ^ c o o ii ^ ^ n. - — ^ ^ ,4-. w CJ x> o o 2E g L. ^ O O »y w' s g E CJ ^ 05 1 U ex 0 c 1 2 s s 1 W3 u ^ C 3 •- i E «/! lie I C/3 V. § t< o a cl 82 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 many species (Robins, flycatchers, ground-nesting species). The Station grounds, therefore, comprised a kind of forest and forest-edge oasis \vheiein vegetational strata, poorly represented, absent, or unmodified in the contiguous forests, could support an exceptionally high population of breeding birds. Appreciation is given here for facilities and courtesies piovided by the University of Virginia Biological Station. LITERATURE CITED Chandler, E. R. 1960. Population studies of the 1959 foray of the Brooks Bird Club at Mountain Lake, Virginia. Raven, 31:63-67. Davis, D. E. 1959. ObseiTations on territorial behavior of Least Flycatchers. V'ilson Bull., 71:73-85. Elton, C., and R. Miller. 1954. The ecological survey of animal communities. J. Ecol., 42:460-496. Kendeigh, S. C. 1961. Animal ecology. Prentice-Hall, Inc., Englewood Cliffs, New Jersey, pp. 135-140. MacArtiiur, R. H., and J. W. MacArtiiur. 1961. On bird species diversity. Ecology, 42:594-598. Oelke, H. 1966. 35 years of breeding-bird census work in Europe. Audubon Field Notes, 20:635-642. PiTELKA, F. A. 1942. High population of breeding birds within an artificial habitat. Condor, 44:172-174. Turcek, F. j. 1951. On the stratification of the avian population of the Quercto- Carpinetum forest communities in southern Slovakia. Sylvia, 13:71-86. Welty, j. C. 1963. The life of birds. Alfred A. Knopf, New York, N.V. p. 348. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF FLORIDA, GAINESVILLE, FLORIDA, 8 APRIL 1968 ANNOUNCEMENT The 1970 Annual Meeting of the Western Bird Banding Association will be held at the Point Loma Inn, San Diego, California, on 24-26 April. Paper sessions and workshop discussions of new techniques and banding problems will he held on Saturday. On Sun- day there will he several field trips including a boat trip to see pelagic species. For more complete information write to Dr. Charles T. Collins, Dept, of Biology, Calif. State College, Long Beach, Calif. 90801. INDEXING POPULATION DENSITIES OF THE CARDINAL WITH TAPE-RECORDED SONG Douglas D. Dow IN Studying habitat utilization by the Cardinal [Richmondena cardinalis } , I required information about the relative densities of populations in dif- ferent regions. As indexing population densities was not a primary objective, I sought a rapid method that would yield consistent and comparable results. Many standard techniques of measuring population density (e.g., Kendeigh, 1944) were impracticable in my large study areas (15 by 15 miles) . Roadside counts (Kendeigh, 1944; Howell, 1951; Hewitt, 1963) did not appear promis- ing as Cardinals are seldom seen along roadways in southern Ontario where I began this work. Since the Cardinal is a loud singer and is netted easily using a recorded song and a mounted bird as a lure, I developed a modified roadside count method utilizing responses to tape-recorded song. Listening counts along roadways are well known to workers in gamebird management (Kimball, 1949; Rosene, 1957; Foote, et ah, 1958; Smith and Gallizioli, 1965; Gates, 1966). Tape-recordings have been used to locate birds (Bohl, 1956; Levy, et ah, 1966). In census methods, Stirling and Bendell (1966) used tape-recorded female calls to stimulate calling of the Blue Grouse [Dendragapus obscurus) , and Giltz (1967) used recorded alarm cries of young Red-winged Blackbirds {Agelaius phoeniceus) to stimulate flight of adults. BASIC TECHNIQUE An automobile is driven to a predetermined point on a road, and three amplified tape-recorded Cardinal songs are played in 15 seconds. An observa- tion period of 30 seconds follows when the number of responding birds are counted. The procedure is conducted four times, bringing the total observa- tion time to two minutes. A “response” is defined as the singing of a Cardinal or the approach of a non-singing male. About 20 points could be sampled in two to three hours if the points were selected at random from a grid of one-mile cells, represented about 60 per cent of the total study area, and were sampled via the shortest connecting route. In other applications when sample points were non-random, e.g., a line transect with points one mile apart, sampling was somewhat faster, and about 10 points could be sampled per hour. The index value is the average number of Cardinals responding at the sampled points. Songs were broadcast from a continuous loop of tape and fed llirough a 12 watt transistorized amplifier and a 7.5 watt loud speaker fitted with a horizontal, circular baffle and mounted vertically on a car window. The baffle and vertical mounting were. 83 84 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 Fig. 1. Cumulative increase in index value with extended observation periods. Plotted points represent the average of 20 points sampled shortly after sunrise on 27 and 28 March 1%6 near Lambeth, Ontario. Solid lines on time scale indicate playing of tape-recorded song. used to distribute the sound as uniformly as possible. A meter, connected across the voice coil, monitored the output level of the signal. The volume level used was empirically determined as that which a listener could just hear at one-quarter mile, approximately the average maximum distance that a singing Cardinal can be heard. Urban areas and heavily travelled paved roads were avoided because of the noise usually associated with them. INCREASE IN RESPONSE OVER NORMAL SINGING Figure 1 shows the effect of continuing observation periods beyond the four normally used. The cumulative increase in index value shows almost no levelling off even by the eighth period. My selection of four observation periods is, therefore, arbitrary and results in a conservative index value; it is a compromise between a large number of observation periods and the maximum number of points that can be sampled in a reasonably short time. There is no doubt that the use of tape-recordings increases the number of birds heard or seen (Table 1). The difference in percentage increase between April and July is typical; the spontaneous singing of the species is decreasing throughout this period while the responses to recordings remain about the same. Douglas D. Dow INDEXING CARDINAL DENSITY 85 InCHE.'VSE in Table 1 Response Attributable to THE Use OF TAPE-RECOHUlNGSt Locality ( Nearest town ) Inde.x value No. of points sampled Sampling dates Witbout taire With tape Percentage increase p* Lambeth, Ontario 18-19 April 0.600 1.000 67 20 NS Melbourne, Ontario 21-22 luly 0.290 0.613 111 31 < 0.025 Melbourne, Ontario 15-16 July** 0.161 0.419 160 31 <0.01 Dresden, Tennessee 22-23 June 2.95 4.05 37 20 < 0.005 t In all additional comparisons, the number of Cardinals responding to tape-recordings was always greater than the number noted without recordings. * Significance level of one-tailed Wilcoxon Signed Rank Test of difference between dependent means (Siegel, 1956). ** Sampled between 10:30 and 13:30 hours. All others were sampled just after sunrise. FACTORS INFLUENCING RESPONSE It is important to standardize as many conditions as possible in a technique such as this. The method is not only susceptible to vagaries of weather, as are most field experiments, but to almost any distracting sound, particularly traffic and tractor noise. The acoustic influence of topography and cover on both broadcast songs and responses presents too formidable a complex of factors for investigation here. It is assumed that such factors cancel each other over a large area. Also, they are largely mitigated in successive comparisons of the same areas. The only main climatic factors that appear to appreciably influence responses are wind and rain. As wind increases, the observed responses decrease. Light to moderate rain seems to inhibit singing, and the drumming of rain on roads and nearby vegetation makes listening impossible. There was no evidence that even very dense fog had any influence on responses, although spontaneous singing seemed somewhat suppressed. The distribution of responses obtained at different times of day is shown in Figure 2. The response drops from a morning peak to a low level in mid-afternoon, then rises again in the evening, but not to the same high level as morning song. This is somewhat similar to the diurnal pattern of spon- taneous singing of many passerine birds I Van Tyne and Berger, 1959:147). Subsequent sampling indicated that the ratio between means of morning and evening samples was not constant enough for reliable estimation of morning 86 THE WILSON BULLETIN March 1970 Vul. 82, No. 1 Fig. 2. Distribution of responses obtained from sampling the same 84 points at four different times of day near Melbourne, Ontario, between 2 and 13 August 1964. {P < 0.01 in Friedman two-way analysis of variance.) values from adjusted evening values. This inconstancy was probably attribut- able to the greater chance of wind in the evening and also to an increase in human activities in some areas. Thus, all further sampling was restricted to morning hours; each sample route was begun between the onset of civil twilight and sunrise, which is about the time that this species normally begins to sing (Allard, 1930; Leopold and Eynon, 1961; Wiens, 1960). Davis (1965) has pointed out that more singing birds may be noted at the beginning of a census period than at the end. I have found the same to be true using tape-recordings, predictable, of course, from Ligure 2. But by repeating several sample routes in reverse order at the same time on different days, I discovered that although more birds are counted in the early half of sampling, the average number remains constant. Abrupt changes in response occur in early spring at the onset of seasonal singing and again late in the summer when reproductive activity wanes. However, during the intervening period, responses remain fairly constant ( Lig. 3 ) while spontaneous singing steadily declines. Herein lies one of the principal advantages of using tape-recordings to stimulate song since the method is not restricted to the spring when birds are most active. In Ontario, consistent results were obtained between late Lebruary and mid- August. In Tennessee, a sudden decline of spontaneous siiming and con- Douglas D. Dow INDEXING CARDINAL DENSITY 87 z Fig. 3. Variability of index among 12 samples of the same 20 points near Lambeth, Ontario, in 1965. Points were sampled approximately every 14 days. current reduction of response to tape-recorded song occurred in late June. However, as spontaneous singing begins somewhat earlier in the season, it is likely that the technique would also be applicable early in the year. I did not experiment with the volume of playback song, but used a standard level previously described. The Cardinal, in Ontario, has a repertoire of some 10 to 19 song types (Lemon, 1966). I used a song that is widespread throughout the species’ range; it corresponded approximately to type WBW of Lemon’s classification. A bird’s reaction to a foreign nonspecific song may he quite different from that to a neighbor’s song (Lrings, et ah, 1958; Weeden and Tails, 1959) . Slightly fewer Ontario birds, at the same set of 20 points, responded to songs recorded 17 miles to the west and 37 miles to the east (mean values of 0.85 versus 1.15 and 0.90 vs 1.15 respectively) ; whereas, slightly more Tennessee birds responded to an Ontario song recorded 627 miles NNE (Ontario, 3.65; Tennessee, 3.52). A reciprocal test in Ontario showed similar results (Ontario, 1.22; Tennessee, 1.32). This suggests that there may be slight differential response associated with different populations. How^ever, as none of these differences are statistically significant, they appear negligible for this application. Lemon (1967) has shown different numbers of songs by Cardinals responding to different dialects, hut his work shows no appreciable difference in numbers of birds responding. Perhaps the greatest disadvantage of this, and of any technique involving listening, is its limited applicability in regions of high population density. Where large numbers of birds can be expected to respond at a point, I think 88 THE WILSON BULLETIN Marcli 1970 Vol. 82, No. 1 Table 2 Comparison OF Results Obtained in Four Study Areas! Ontario Tennessee Melbourne Simcoe Elmira Dresden Area (square miles) 625 625 225 225 No. of points sampled 160 160 140 140 Total birds responding 155 60 31 598 Index value* 0.97 0.38 0.22 4.3 Range of birds per point 0-4 0-2 0-2 1-8 t Areas were sampled in late April and early May from 1965 to 1967. , , x,, n- * A significtint difference (P 0.001) was found among these values using the Kruskal-Wallis one-way analysis of variance (Siegel, 1956). that close singers tend to mask more distant ones, resulting in too few birds being scored. I believe that the low increase in Tennessee ( Table 1 ) resulted because not all birds responding to the tape were actually counted; whereas, the fewer birds singing spontaneously had a higher probability of being noted. The bias introduced by singing females is considered to be negligible as I found during sampling that fewer than one per cent of singing Cardinals of known sex were female. A further consideration should be kept in mind by anyone using this or any technique involving tape-recording. A recorded song or call, unless played at a volume well below the normal singing level of the species, can never be regarded as a constant stimulus. Birds responding to a recording probably increase the stimulus value for other conspecifics within hearing range. Consequently, in a dense population, which may only be a very local condition, a recording may have a higher effective stimulus value than in a sparse population if few birds are singing prior to the broadcast; the opposite may be true if most birds are already singing. APPLICATIONS OF THE TECHNIQUE The technique has proved useful in providing a relative index of abundance of the Cardinal in large study areas in different parts of its range. The recording used was obtained locally for each study area. The results are shown in fable 2. The area in Ontario with the lowest index value was selected because of its location on the periphery of the CardinaTs range; the Tennessee aiea was selected as piobably being representative of the center of the range. A significant difference [P < 0.001 ) was found among the four indices. Temporal changes in density can be detected similarly. I checked 20 points near Lambeth, Ontario, twice in 1965 (22 April and 31 July) and 1966 (22 Douglas D. Dow INDEXING CARDINAL DENSITY 89 Fig. 4. Each solid circle shows the center of an area of 20 points sampled in July 1965. The total number of birds responding at these points is shown above the location. Below the location is the number of birds per 100 hectares of woody cover, where cover was measured from aerial photographs in a circle of one-quarter mile radius about each sample point. Letters A, B, and C show the approximate center of the study areas of Table 2, i.e., Melbourne, Simcoe, and Elmira respectively. The cross-hatched zone shows the edge of the Cardinal’s range based on four 30-mile transects (straight lines) sampled in August 1966 in addition to the figures shown. A few small, extralimital populations are known to the north and east of this area. March and 5 August) . The two sets were averaged for each year, yielding indices of 1.02 and 1.40 respectively. The significant difference (P < 0.05 in Wilcoxon Signed Rank Test) suggested an increase in the population of the area. The technique has proved very useful for obtaining information on dis- tribution (Fig. 4). A gradient of density can be seen across southern Ontario from west to east. The difference in the index value of New York state and the adjacent regions of Ontario may result from the heavily industralized urban area along the Niagara River acting as a barrier or buffer to the recent build-up in population density in New York described by Beddall (1963). I found the edge of the range to be fairly abrupt, and not apparently correlated with type of vegetation. 90 THE WILSON BULLETIN Maicli 1970 Vol. 82, No. 1 RELATION OF INDEX TO POPULATION DENSITY This technique was developed to yield a relative index, not an absolute measure of density. Because of the masking effect previously suggested in very high densities, the relationship between the index value and the real density is likely linear only in low densities, d he measurement scale of the index is undoubtedly at least ordinal, i.e., an increase in index value under similar environmental conditions indicates an increase of unspecified magni- tude in population density. Independent estimates of density in two of my study areas using the method of Hayne (1949) yielded 0.74 males per ha (30 per 100 acres) of undifferentiated habitat in Tennessee and 0.012 per ha (0.48 per 100 acres) in Ontario (Elmira). Of course, many more areas of different density would require sampling by the two methods to establish a continuous relationship. SUMMARY A roadside technique was developed for indexing population densities of the Cardinal by counting birds after the playing of a tape-recorded song. The mean number of birds responding at sample points was used as an arbitrary index. The use of tape-recordings resulted in a marked increase of birds seen and heard. Numbers of responding birds were influenced by rain, wind, and time of day. Seasonal fluctuation was relatively small, permitting tbe technique to be used into late summer. The method has been used to obtain indices of relative abundance in different parts of the Cardinal’s range, to compare the same area for annual differences, and to delimit the range in southern Ontario. The relationship between index and actual density is virtually unknown, but is probably close to linear in low densities. Hence, the technique is better suited to moderate population densities than to very high ones. Where a rapid method of detecting dif- ferences in densities is required, the technique should work well for any species having a loud or distinctive song or call. ACKNOWLEDGMENTS I should like to thank S. Pluzak, Department of Zoology, University of Western Ontario, for assistance in design and construction of the portable apparatus used in broadcasting recorded songs. I am grateful to the Ontario Department of Lands and Forests both at Toronto and Aylmer West, Ontario, for permitting me to examine aerial photographs. Particular thanks is due to L. Stock of the Aylmer West office for his assistance. This work was supported by an Ontario Graduate Fellowship and a National Research Council Studentship to the author. Most of the financial support was through grants from the National Research Council of Canada to D. M. Scott of the University of Western Ontario. I am grateful to him for suggestions made during the course of this work and for his reading of an early draft of this paper. LITERATURE CITED Allard, H. A. 1930. The first morning song of some birds of Washington, D.C. ; its relation to light. Amer. Naturalist, 64:436-469. Douglas D. Dow INDEXING CARDINAL DENSITY 91 Beddall, B. G. 1963. Range expansion of the Cardinal and other ])irds in the nortli- eastern states. Wilson Bull., 75:140-158. Bout, W. H. 1956. Experiments in locating wild Chukar partridges by use of recorded calls. J. Wildl. Mgmt., 20:83-85. Davis, J. 1965. The ‘ ■‘singing male” method of censusing birds: a warning. Condor, 67:86-87. Foote, L. E., H. S. Peters, and A. L. Finkner. 1958. Design tests for Mourning Dove call-count sampling in seven southeastern states. J. Wildl. Mgmt., 22:402-408. Frings, H. and M., j. Jumber, R. Busnel, J. Giban, and P. Gramet. 1958. Reactions of American and French species of Corviis and Larus to recorded communication signals tested reciprocally. Ecology, 39:126-131. Gates, J. M. 1966. Crowing counts as indices to cock pheasant populations in Wiscon- sin. J. Wildl. Mgmt., 30:735-744. Giltz, M. L. 1967. What is being done about blackbird control in Ohio. Proc. N. Amer. Conf. Blackbird Depredation in Agri. pp. 39-41. Hayne, D. W. 1949. An examination of the strip census method for estimating animal populations. J. Wildl. Mgmt., 13:145-157. Hewitt, 0. H. 1963. Development of a roadside count method for censusing breeding Redwinged Blackbirds i Agelaius phoeniceus) . Angew. Ornithoh, 1:123-125. Howell, J. C. 1951. The roadside census as a method of measuring bird populations. Auk, 68:334-357. Kendeigii, S. C. 1944. Measurement of bird populations. Ecol. Monogr., 14:67-106. Kimball, J. W. 1949. The crowing count pheasant census. J. Wildl. Mgmt., 13:101-120. Lemon, R. E. 1966. Geographic variation in the song of Cardinals. Canadian J. Zook, 44:413-428. Lemon, R. E. 1967. The response of Cardinals to songs of different dialects. Anim. Behav., 15:538-545. Leopold, A., and A. E. Eynon. 1961. Avian daybreak and evening song in relation to time and light intensity. Condor, 63:269-293. Levy, S. H., J. J. Levy, and R. A. Bishop. 1966. Use of tape recorded female quail calls during the breeding season. J. Wildl. Mgmt., 30:426-428. Rosene, W., Jr. 1957. A summer whistling cock count of Bobwhite Quail as an index to wintering populations. J. Wildl. Mgmt., 21:153-158. Siegel, S. 1956. Nonparametric statistics for the behavioral sciences. McGraw-Hill, New York. Smith, R. H., and S. Gallizioli. 1965. Predicting hunter success by means of a spring call count of Gambel Quail. J. Wildl. Mgmt., 29:806-813. Stirling, L, and J. F. Bendell. 1966. Census of Blue Grouse with recorded calls of a female. J. Wildl. Mgmt., 30:184-187. Van Tyne, J., and A. J. Berger. 1959. Fundamentals of ornithology. John Wiley, New York. Weeden, j. S., and j. B. Falls. 1959. Differential response of male Ovenhirds to recorded songs of neighboring and more distant individuals. Auk, 76:343-351. Wiens, A. W. 1960. Sunrise, sunset, and the song of the Cardinal. Bull. Kansas Ornithoh Soc., 11:13-14. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF WESTERN ONTARIO, LONDON, ON- TARIO. (PRESENT ADDRESS: DEPARTMENT OF ZOOLOGY, UNIVERSITY OF QUEENSLAND, BRISBANE, AUSTRALIA), 26 FEBRUARY 1968. GENERAL NOTES Oil the validity of some supposed “first state records” from Yucatan.—^In a paper presenting miscellaneous “noteworthy records of birds from the Republic of Mexico, Thompson (Wilson Bulb, 74: 173-176, 1962) included a number of specimens collected by George F. Gaumer, now in the University of Kansas Museum of Natural Histoiy. These were listed with no qualifying remarks whatsoever, mostly prefaced by the asterisk used by Thompson to indicate “first occurrences in Mexican states. Thompson may not have been aware that the data on Gaumer specimens are notoriously unreliable. Gaumer was a physician who resided in Yucatan during the late nineteenth and early twentieth centuries. Although a tireless collector, he was careless and in- consistent about labeling his specimens. Many were apparently labeled from memory months and even years after collecting (Paynter, Peabody Mus. Nat. Hist. Bull., 9: 79 [and elsewhere], 1955). Many of Gaumer ’s specimens labeled “Cozumel Island represent mainland species not otherwise known from the island, and it is now the custom among students of Mexican birds to disregard records from Cozumel and other islands in the Yucatan I’egion that are based solely on Gaumer specimens (Paynter, op. cit.; Bond, 6th Suppl. Check-list Bds. West Indies (1956): 4^5, 1961; Parkes and Phillips, Condor, 69: 78, 1967). Like most Gaumer specimens, those at the University of Kansas bear only the Mu- seum’s labels. This is not necessarily an indication that an original Gaumer label has been removed. Gaumer was apparently in the habit of sending off boxes of unlabeled specimens to various museums, where “Yucatan” labels would be attached. Most of the Kansas specimens are simply labeled “Yucatan,” and Thompson has taken this to mean the state of Yucatan, which occupies only the northernmost third of the Tucatan Peninsula. In Gaumer’s day the name “Yucatan” encompassed the entire area now divided among the states of Yucatan and Campeche and the territory of Quintana Roo. There is no justification for assuming that old “Yucatan” specimens necessarily constitute records for the area included in the modern state of that name. Individual records in Thompson’s paper based on Gaumer specimens are discussed below. Sharp-shinned Hawk (Acclpiter stnatus velox). — Two specimens labeled Cozumel Island, considered by Thompson to he the first record from Quintana Roo. This species is apparently a rare migrant in the Yucatan area (Paynter, op. cit.: 58) and in the West Indies (Bond, Birds of the West Indies, 56, I960), so a record from Cozumel is at least plausible. The species should not, however, he added to the Cozumel and Quintana Roo lists on the sole basis of these Gaumer specimens. Lineated Woodpecker (Dryocopus lineatus slmilis) . — Two specimens alleged to have been collected on Cozumel Island. This is a most implausible record. No other visitor to the island has reported this large, noisy, conspicuous woodpecker. During three collecting trips to Cozumel, neither I nor any of my field companions (A. R. Phillips, R. W. Dickerman, Juan Nava S.) saw either this species or any evidence of the diggings of a woodpecker any larger than the resident Centurus. The Lineated Woodpecker should he added to the list of “land birds apart from what are certainly North American migrants” that are known from Cozumel only from dubious Gaumer specimens, as published by Bond (Caribbean J. Sci., I: 41-42, 1961). Fork-tailed Flycatcher (Muscivora tyrannus) . — One specimen listed as the “first record” from the state of Yucatan. The species has been reported from Campeche and Quintana Roo; although its occasional occurrence in what is now the state of Yucatan 92 March 1970 Vol. 82. No. 1 GENERAL NOTES 93 would not be unlikely, it should not be so recorded on the basis of a Gaumer “Yucatan” specimen. Western Kingbird iTyrannus verticalis) . — One specimen from “Yucatan.” This species has not been reported from any locality in the Yucatan Peninsula, or, for that matter, anywhere in Caribbean Mexico south of San Luis Potosi. This specimen is not an acceptable basis for the inclusion of the Western Kingbird in the list of birds of the Peninsula. Common Tody-Flycatcher (Todirostrum cinereum jinitimum) . — This “Yucatan” speci- men may or may not be authentic, but is of no importance. Paynter (op. cit.: 201) re- corded the species from Campeche and Quintana Roo. Dale A. Zimmerman saw a singing male at Sisal, Yucatan on 9 May 1956. This is the earliest authentic record known to me from the state of Yucatan, hut numerous individuals have been seen and several collected since that time. William H. Buskirk of Louisiana State University estimated at 48 the number of Tody-Flycatchers in a narrow strip of coastal scrub, some 2% km long, near Progreso on 21 August 1967. Violet-green Swallow iTachycineta thalassina lepida) . — There is no other report of this species from anywhere in the Yucatan Peninsula, or, to the best of my knowledge, anywhere in the Caribbean lowlands of Mexico. It is therefore a temptation to dismiss this record out of hand. However, the specimen is the only mainland one among the Gaumer specimens listed by Thompson that hears any data more precise than simply “Yucatan.” According to the label, the bird was taken in 1914 at the “Port of Silam” [=r Dzilam Puerto]. Even with a specified locality and year, however, some doubt must linger about the authenticity of a unique Gaumer record such as this one. 1 would recommend that the Violet-green Swallow be placed on the hypothetical list for the Yucatan Peninsula. Orange-crowned Warbler (Vermivora celata orestera) . — There is no other published record of this species from the Yucatan Peninsula, and the very fact that the one Gaumer “Yucatan” specimen represents the Rocky Mountain subspecies would ordinarily he enough to discredit the record. However, on 8 November 1963, an Orange-crowned Warbler was netted in the coastal scrub near Progreso by Phillips, Dickerman, and the writer. To our surprise, this bird was, indeed, referable to orestera. A second specimen, netted in the same area on 23 January 1%5, is also nearest orestera, although approaching celata in the color of the interscapular area (A. R. Phillips, in litt.). It is possible, therefore, that Gaumer’s specimen is authentic, but it is fortunate that examples with full data exist to substantiate the occurrence of this western form in Yucatan. Nashville Warbler (Vermivora ruficapilla ruficapilla) . — One specimen from “Yucatan.” Paynter (op. cit.) did not list this species at all from the Peninsula, but Miller et al. (Pacific Coast Avifauna 33: 240, 1957) record the nominate race from Campeche without further details. It is conceivable that the species might reach Yucatan, but the one Gaumer specimen should not be used as the basis for a definite statement. Northern Waterthrush (Seiurus noveboracensis “noveboracensis”) . — This species is a common and well-known migrant and winter visitor throughout the Yucatan Peninsula and adjacent islands. Thompson lists one “Yucatan” specimen identified as the “first record” for the state of Yucatan of the nominate race, which Paynter (op. cit.: 254) reported only from Banco Chinchorro and Cozumel Island, Quintana Roo. Paynter referred all of his own mainland and island specimens (as well as, tentatively, his sight records from additional islands) to S. n. notabilis. However, I agree fully with Eaton (Auk, 74: 229-239, 1957) that the variations in color and size exhibited by this species cannot be utilized in any meaningful definition ol geographic races. Having 94 THE WILSON BULLETIN March 1970 Vul. 82, No. 1 seen for myself the series of breeding birds upon which Eaton’s conclusions were based, I must reject Monroe’s rather tentative demurrer (Amer. Ornithol. Union Monogr., 7: 335-336, 1968) to the effect that “three races seem to he recognizable.” Monroe did not admit “u/zgmosns” of Newfoundland, which, as Eaton pointed out, represents clinal extremes in both color and size, and is one of the few discrete populations that approach definability. Specimens I collected on 4 and 18 November 1965 on Cozumel Island represent virtually the extremes in whiteness and yellowness of underparts within this species, but I attach no taxonomic significance to this, and use the binomial for all Northern Waterthrushes. Wilson’s Warbler (JVilsonia pusilla pz7eo/ato) .— This species is such an abundant migrant and winter visitor throughout most of Mexico that its apparent total absence fiom the Yucatan Peninsula has been all the more conspicuous. In the face of the lack of any authentic specimens, the fact that no less than four Gaumer specimens hear Yucatan labels would be enough to suggest the improbability of their supposed origin. Never- theless, it is likely that the Wilson’s Warbler is at least a rare transient in the Yucatan Peninsula. Specimens have been collected in British Honduras, at the southeastern base of the Peninsula (Russell, Amer. Ornithol. Union Monogr., 1: 159-160, 1964). I have received from William H. Buskirk a convincing account of sight records of single birds seen 13 and 14 September 1967 at Puerto de San Eelipe, near Rio Lagartos, Yucatan. The Gaumer specimens are referable to W. p. pileolata, whereas Russell floe, cit.) identified British Honduras specimens as W. p. pusilla. Mr. Buskirk’s sight record is, of course, unidentifiable suhspecifically. I believe the species can safely be admitted to the list of birds of the Yucatan Peninsula, but the true status of the subspecies occur- ring there must await collection of specimens of more certain origin than those of Gaumer. Baltimore Oriole (Icterus galbula). — This species has been recorded from Campeche and Quintana Roo, and could conceivably occur on migration within what is now the state of Yucatan, but the single Gaumer “Yucatan” specimen cannot substantiate such occurrence. Montezuma Oropendola (Gymnostinops inontezuma) . — The attribution of this large rain forest species to the arid state of Yucatan on the basis of a Gaumer “Yucatan” specimen is perhaps the most implausible of Thompson’s “first records.” This oropendola is known from suitable habitat in Campeche and Quintana Roo, in the southern part of the Peninsula. Western Tanager ( Piranga ludoviciana) . — There are authentic records of this western species on the Caribbean slope of Mexico, hut none from the Yucatan Peninsula. The pair of birds in the Gaumer collection should not form the basis for a statement of occurrence of this species either in the Peninsula or in the state of Yucatan. Black-headed Grosbeak (Pheucticus melanocephalus melanocephalus) . — The pair in the Gaumer collection, if authentic, would represent not only the first record for the state and peninsula of Yucatan, hut the entire Caribbean lowlands of Mexico as well. The Gaumer specimens do not provide adec]uate proof of such occurrence. ACKNOWLEDGMENTS I am indebted to Dale A. Zimmerman and William H. Buskirk for permission to utilize data from their unpulzlished field notes, and to Allan R. Phillips and Robert W. Dickerman for reading the manuscript as well as for companionship in the field in Mexico. Dr. Phillips also supplied some essential points of information on distribution. Eor the privilege of examining some of the Ganmer specimens in the University of Kansas Museum of Natural History, I am indebted to Richard E. Johnston and Robert M. March 1970 Vdl. 82, No. 1 GENERAL NOTES 95 Mengel. My field work in Mexico was supported liy llie Edward O’Neil Fund of Carnegie Museum and the Frank M. Chapman Memorial Fund of the American Museum of Natural History. Permits to collect birds in Mexico were obtained through ihe kindness of Rodolfo Hernandez Corzo of the Departamento de Conservacion de la Fauna Silveslre. — Kenneth C. Pahkes, Carnegie Museum, Pittsburgh, Pennsylvania, 5 December 1968. High density Mallard nesting on a South Dakota island. — In May 1967, com- mercial fishermen reported large numbers of Mallards (Anas platyrhynchos) nesting on a 19-acre island located in the southeastern portion of 4,360-acre Lake Albert in Kingsbury and Hamlin Counties, eastern South Dakota. We visited the island on 18 and 27 May 1967 and confirmed the presence of numerous nesting Mallard hens. Lake Albert is a large, open-water lake which supports fish populations. Emergent aquatic vegetation is scarce, and is confined to a few protected shore areas. The island lies about 450 yards northwest of the southeast shore of the lake. On the western half of the island is a 9-acre flat, while the eastern half contains a slightly sloping open area of about 2 acres surrounded by trees and shrubs. The 9-acre flat was dominated by a dense growth of tall nettles (Urtica procera) about 6 to 18 inches high during May. Patches of figwort iScrophiilaria sp.), snowberry (Symphoricarpos occidentalis) , wild black current (Ribes americanum) , Missouri gooseberry (R. missourienses) , chokecherry iPrunus virginiana) , and rose (Rosa sp.), also grow on the 9-acre flat and other portions of the island. Indian hemp (Apocynum sibiricum) , common milkweed (Asclepias syriaca) , and sunflower ( Helianthus annuus) are also found in open areas, while blue- grass iPoa sp.) was common in the more wooded eastern portion of the island. The entire island is ringed by trees, including box-elder (Acer negundo) , American elm (Ulmus americana) hackberry (Celtis occidentalis) , green ash (Fraxinus pennsylvanica) , and willow (Salixsp.). In 1967 and 1968 we searched approximately 50 per cent of the 9-acre flat after preliminary investigation disclosed that nearly all nests were confined to this area. In 1967, 39 Mallard nests were found, including 36 active and 3 abandoned. In addition, three hens were flushed from cover and their nests were not located. The same area was searched on 27 May 1968; 28 active nests were found, two hens were flushed from cover and their nests were not located. Of 67 nests observed during the two years, placement in various cover types was as follows: tall nettle, 91 per cent; gooseberry, 5 per cent; snowberry, 3 per cent; and bluegrass, 1 per cent. Based upon our sample of about 50 per cent of the preferred nesting cover, we estimated that there was a minimum of 78 and 60 nests in 1967 and 1968, respectively on the island. Within the area sampled in 1967, the average distance between nests was 34 feet (range 7-150 feet). Measurements were not made in 1968. Clutch sizes averaged 10.4 eggs in 1967 and 8.8 eggs in 1968. Clutch sizes ranged from 6 eggs to 18 during both years with larger clutches more common in 1967 when a higher nest density was found. In 1967, six clutches contained 14 or more eggs while only one clutch contained 14 or more eggs in 1968. No evidence of activity by egg predators was observed during the two years, except for the occurrence of a large garter snake (Thamnophis sp.) in 1967. Of 67 nests observed, none had been destroyed by predators although three nests had been abandoned. A Great Horned Owl (Bubo virginianus) nest containing two young was on tbe island in 1967 ; however, there was no evidence that the owls had been preying on Mallards. During our visits to tbe island, pairs were continually observed moving between tbe 96 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 island and wetlands on the adjacent mainland. Numerous aerial pursuit flights were observed, but these intraspecific conflicts did not prevent the establishment of a high nest density, nor interfere with an apparently high hatching success. Lone and giouped drakes utilized waiting sites on waters surrounding the island while hens were laying or incubating. Several males were observed waiting for hens on land in close proximity to nests. On 27 May 1967 about 30 drakes were observed loafing together on an exposed, elevated site in the 9-acre flat. Many of the nesting hens in surrounding cover were in mid to late stages of incubation during this period. The wind-swept, open water lake surrounding the island provided poor brood rearing habitat. Apparently, most hens moved their broods about 450 yards to tbe southeast shore where a large permanent marsh was located. We observed several newly hatcbed Mallard broods on this marsh on 27 May 1967. Other ground nests found on the 9-acre flat included Mourning Doves ( Zenaidura macroura) , and one Ring-necked Pheasant iPhasianus colchicus) . One Mourning Dove ground nest in nettles was located within 3 feet of an active Mallard nest. The island was purchased by tbe South Dakota Department of Game, Fish and Parks in February 1944. During tbe mid-1950’s adjacent landowners complained of tbe noxious weeds on the island, since they felt it to be a seed source that contaminated their fields. Consequently, the Department sprayed and cultivated the 9-acre flat for two consecutive years. This disturbance may have been responsible for increases in nettles since the mid-1950’s. This extremely high nest density contrasts with the usual widely-dispersed nest place- ment of Mallards in other portions of the prairie pothole habitat in North America. Such a concentration of nesting Mallards is probably a result of high nesting success and a high rate of migrational homing of both adult and first-year nesting hens. This high island nesting density of Mallards is similar to that described by Duebbert (Wilson Bulb, 78:12-25, 1966) for Gadwall (Anas strepera) nesting mainly in nettles on an island at Lower Souris National Wildlife Refuge, North Dakota. Boyd and Campbell (The Wildfowl Trust, 18th Ann. Rept. 36-42, 1967) reported finding 268 Mallard nests on an 105-acre island in central Scotland in 1966. We wish to thank Harold F. Duebbert for his suggestions and helpful criticism of the manuscript. — Rod C. Drewien and Larry F. Fredrickson, South Dakota Department of Game, Fish and Parks, Aberdeen, South Dakota (RCD) and Brookings, South Dakota (LFF), 17 March 1969. Courtship display observed between two species of buleos. — The following details of courtship behavior between two species of Buteo were recorded by Frank Kish, Associate Curator at the Topeka Zoo. The two flight cages for raptors at the Topeka Zoo are made of two regulation baseball backstops which have been joined together. The interior of each has several perches and two shelter boxes 2Y> X 2 X 2 feet wbich are open in front and have no bottom. A perch is located within each box. In tbe cage concerned in the observations, one of these boxes is located beneath an oak tree growing outside of the enclosure. The tree would make the box more desirable as a nest site offering “concealment” and pro- tection from the elements. On 2 January 1968 two adult Red-tailed Hawks (Buteo jamaicensis) , a male and a female, one adult male Swainson’s Hawk (Buteo stvainsoni) . and an adult male Harlan’s Hawk (Buteo harlani) were in this enclosure. The male Red- tail had suffered a broken wing and could not fly at all well. Both Redtails were Marcli 1970 Vol. 82. No. 1 GENERAL NOTES 97 local birds (northeastern Kansas) and the Swainson’s Hawk and Harlan’s Hawk had Iteen shipped from Calgary, Alberta, Canada. All of these liirds lived in harmony together. In mid-January, courtship displays between the female Redtail and the male Swainson’s Hawk began and lasted approximately one month. The female Redtail’s displays consisted of inviting the male Swainson’s by calling and wing-flapping, to the shelter box which seemingly she had come to regard as a nest. The male Swainson’s responded by flying over and landing on the box beside her. The female tried to solicit the male by spreading the feathers covering the cloaca and by lifting her tail. This type of display occurred quite frequently and was more intensive in the morning. No food begging, courtship feeding, or nest building was seen. The male responded only by perching next to the female and no copulation was ever observed. On 26 January 1%8, several weeks after the commencement of the female Redtail’s displays, a new healthy male Redtail was introduced into the enclosure. This bird had been hand-raised from a day-old nestling and subsequently trained to the glove after the manner of falconers. The bird, thus raised and tamed was more easily in- timidated by other birds. The female Redtail attacked the new male so frequently that he was removed on the following day. It is highly unlikely that such courtship behavior would occur in nature because of the abundant choice of mates of their own species presumably available to free-ranging birds. A. P. Gray ( Bird hybrids, A check list with bibliography. Commonwealth Agricultural Bureau, Farnham Royal, Bucks, England, 1958) indicates that definite, proven hybrids between hawks in general and Buteos in particular are rare and that no cases of hybridiza- tion between B. jamaicensis and B. swainsoni are known. We would like to thank Gary K. Clarke, Director of the Topeka Zoo, for permission to publish this material, and Robert M. Mengel, of the University of Kansas Museum of Natural History, for critically reading this paper. — Bruce R. Woliiuter, University of Kansas Museum of Natural. History, Lawrence, Kansas and Frank Kish, Topeka Zoo- logical Park, 632 Gage Boulevard, Topeka, Kansas, 29 November 1968. Food habits of wintering Sparrow Hawks in Costa Rica. — Sparrow Hawks (Falco sparverius) begin arriving in Costa Rica from the north in August or September. Some remain there for the winter, occupying the more open habitats, often those under culti- vation or cleared for pasture. They depart for the north about April of the following spring. My observations show that during this period they are solitary, apparently territorial and, once in possession of a sufficiently food-rich territory, alisolutely sedentary. I recorded several wintering individuals which could invariably be found on their territories and in the vicinity of a few favored perches throughout their stay. A male bird which arrived on the grounds of the Inter-American Institute of Agri- cultural Sciences near Turrialba about mid-October, 1967, disappeared on 29 March, 1968. It took up residence in an area about 400 m in diameter which it never left. Usually it could be found along some electric power lines which crossed the area, either perched on the wires or on the tops of the poles. The area was bisected by a paved road parallel to the power lines. One side of the road was occupied by hedged lawns and a short-grass horse pasture; and on the other side was a wet pasture with rank grass, scattered trees, and overgrown fencerows. The hawk hunted primarily on the lawns and horse pasture, where it generally dropped directly onto its prey from a perch. When it hunted over the high grass, it frequently hovered on the wing after the kestrel fashion. 1 recorded 97 successful prey captures 98 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 out of 246 attempts. All prey were captured on the ground. In 41 cases, the prey item was positively identified through binoculars or hy the examination of fragments dropped in feeding. Of the identified items, 9 were shortdioined grasshoppeis (Acrididae), 19 were longdiorned grasshoppers (Tettigoniidae) , and 11 were lizaids of the genus Anolis ( prohahly Anolis Hmijrons) . One item was a large cockroach (Blattidae) and the last was a small coluhrid snake. This list is probably biased since grasshoppers and other large insects were difficult to identify at a distance hut were abundant in the area. In about 30 cases where identity could not he certainly established, it appeared that the bird was tearing off wings as it characteristically did with large insects. The lizards and snake on the other hand, were easily distinguished hy their long tails which hung down from the hawk’s talons. I recorded about thirty additional prey captures hy other individuals wintering in the Turrialba area, but, because of the greater distance from the observer, only four of these could be identified. Two were Anolis lizards and one was a tettigoniid grasshopper. A good-sized Ameiva lizard (prohahly Ameiva f estiva) was taken l)y a wintering female. Ameiva lizards were present on the territory of the male hawk at the Institute, but no captures were recorded. It may he that the significantly larger size of females permits them to take larger prey, hut these few data are not sufficient to justify such a state- ment. No warm-blooded prey or attempts on warm-blooded prey were recorded. Suitable mammals are uncommon and the place that they oecupy in the diets of hawks in the temperate zones is largely filled by the abundant reptiles and large insects. Birds are not molested hy wintering Sparrow Hawks and show no great fear of them, often perch- ing on the same tree or power line. These observations were made while the author was engaged in a study of avian ecology supported by a Harvard University Scholarship, NSF grant number GB7346 (Reed C. Rollins, principal investigator), and hy a grant-in-aid of research from the .Society of Sigma Xi. — Robert E. Jenkins, Museum of Comparative Zoology, Harvard U niversity, Cambridge, Massachusetts 02138, 13 February 1969. Marsh Hawk chases crows mohhing owl. — On 5 November 1968, at 08:00, near Shabbona, DeKalb County, Illinois, I observed a Great Horned Owl {Bubo virginianus) that was perched on the ground near the edge of a partially picked corn field. A drainage ditch paralleled the border of the field and a dense growth of annual weeds, grasses, and willows iSalix sp.) extended for about 30 feet on both sides of the waterway. My attention was directed to the owl hy the raucous calls of eight Common Crows (Corvus brachyrhynchos) that were mohhing it. After the crows had been swooping at the owl and calling almost continuously for about four minutes, the owl flew toward the ditch and landed on a fence post. The crows’ activity seemed to become intensified during the owl’s short flight. Four of the crows landed on fence posts, all in the same direction from the owl, and the others continued flying about near the owl and calling. About two minutes later a female-plumaged Marsh Hawk {Circus cyaneus) flew in low over the adjacent corn field and briefly chased each of the four flying crows. The crows maneuvered swiftly and left the immediate area. The hawk then dived at each of the perched crows and caused them to fly. All eight crows flew to a row of large trees about ^4 mile north and landed. The hawk left the area immediately and disappeared to the west (08:08). Approximately one minute later the owl (possibly in response to my presence) flew for about 200 yards and landed on the ground in a hay field. March 1970 Vol. 82. No. 1 GENERAL NOTES 99 At 08:12 the crows arrived at the owl’s new location and resumed mobl)in}f activities. Within two minutes a Marsh Hawk appeared from out of the west and cliased each crow for a brief period. The crows quickly departed to the north and the hawk flew west • 08:15). Neither species returned to the hay field during the next 45 minutes. The significance of this observation cannot be determined at this time. It seemed that the Marsh Hawk was attracted by the noise generated by the mobbing crows; however, the hawk did not return after its second departure when the same crows mobbed two Short-eared Owls {Asia jlammeus) that were flying over a hay field mile north of the Great Horned Owl’s location. — William E. Southern, Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115, 23 January 1969. Ruddy Turnstones making use of Yellow-crowned Night Herons for food- finding.— On 5 June 1948 I was watching a number of Yellow-crowned Night Herons [Nyctanassa violacea) feeding on the innumerable crabs on the coastal mudflats at the mouth of the Coppename River, Surinam. Near one of them stood two Ruddy Turnstones (Arenaria interpres) which swallowed the remains of a crab which fell out of the heron’s bill on the mud. The turnstones obviously watched the feeding herons as each time a heron captured a crab they hurried toward the feeding bird and swallowed the wasted morsels as soon as they fell on the mud. The turnstones never chased or bothered the herons but simply waited their turn and the herons apparently did not take any notice of them. — F. Haverschmidt, Wolfskuilstraat 16, Ommen, Holland, 29 March 1969. Comniou Terns pirating fish ou Great Gull Island. — In 1967, while working in the Great Gull Island tern colony, located 7 miles ENE of Orient Point at the eastern end of Long Island, New York, I saw adult Common Terns [Sterna hirundo) pirating fish brought in to feed the young. An adult would fly in carrying a fish. The young tern would rush out, grasp the fish in its bill and at that moment a second adult Common Tern would dart in and make off with the fish. The young, still holding the end of the fish, would be lifted 8-10 feet in the air, then would drop to the ground without the fish. The fall did not seem to hurt the young tern. Pirating of Common Terns by Common Terns was seen on several occasions, but I did not see this pattern in Roseate Terns (Sterna dougallii) which also nested on the island. In the three years I have worked on Great Gull Island I have seen pirating only in 1967. Bannerman (Birds of the British Isles, p. 152, 1962) reports Roseate Terns in the Fame Islands as pirating fish regularly from Arctic Terns (Sterna paradisaea) . Austin (Bird-Banding, 5:155-171, 1934) states that the degree of food abundance for a tern colony can be estimated from the number of fish found on the ground in the colony during the season. Using this criterion the bait fish, on which the terns feed were in short supply in our area in 1967. In contrast to 1966 I found very few fish on the ground near these nests and less variety in those I did find : 3 species in 1967, in contrast to 9 species in 1966. In 1968 not many fish were found in the colony, but growth rate studies of the young Common and Roseate Terns on the island (LeCroy and Collins in prep.), suggest the food supjdy was better in 1968 than in 1%7. As far as I know there are no data on relative abundance of bait fish for this area for the period 1966-1968. Dr. William A. Lund, Jr., working on blucfish (Fomatomus 100 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 sidtutTix) in areas near Great Gull Island reports ( pers. comm.) his impression that 1966 was a good year for bait fish, in 1967 bait fish were very low and in 1968 they were more abundant. Bluefish and terns are often seen feeding in the same areas, the fish chasing the bait to the surface where the terns dive for it. Since pirating of fish by Common Terns seems to be exceptional in the Great Gull Island colony, its occurrence may have been correlated with a shortage of bait fish. Where pirating is seen regularly, as described for the Fame Islands Roseate Terns the pattern may have had its beginning during a period when bait fisb were in short supply. — Helen Hays, 14 East 95th Street, New York, New York 10028, 5 March 1969. Sand-kicking camouflages young Black Skimmers. Bent (U.S. Natl. Mus. Bull., 113:315, 1921) describes young Black Skimmers (Rynchops nigra) digging them- selves into depressions on the beach when disturbed. “From their earliest stage the young skimmers have a habit of scratching themselves into a hollow and lying absolutely flat upon the shell-covered beach. While this habit is displayed mostly by the downy young, I have seen it exhibited to a great extent by tbe feathered young when tlie young birds are able to run about and danger threatens. Then they will throw themselves flat on the shells of the beach and scratch alternatively with their little webbed feet backward. They make 15-20 movements before they snuggle down to rest, and while their legs are in action they make the shells fly most energetically. When the hollow is dug sufficiently to allow them to lie flush with the surrounding beach they remain absolutely motionless. . .” Stone (Bird studies at old Cape May, 11:604, 1937) mentions the difficulty of seeing young skimmers as they lay in depressions with sand apparently drifted around them. On 7 August 1968 we visited a sand bar in Shinnecock Bay at the eastern end of Long Island, New York, where terns and skimmers nest. As we walked into the colony we saw spurts of sand ahead of us. As we approached the sand stopped flying and there would be a young skimmer lying very still, partially covered with sand. On 27 August 1968 we visited a section of beach about one mile south of Stone Harbor. New Jersey where skimmers were nesting. We found a nest where one egg had hatched and two eggs were still left in the nest. The young skimmer, which looked at most a day old, was stdl kicking sand into the air as we stood over it. The sand fell on the back of the bird. The sand-kicking as Bent suggests does function in digging a depression in which the bird lies. It seemed to us equally important, however, that the sand which is kicked into the air falls on the liack of the young skimmer partially covering it, and from our point of view, at least, helping to camouflage it. It seems likely that Stone’s drifted sand could have been sand kicked by the young skimmers. The camouflage aspect of this kicking may not be realized if the substrate is composed of small stones, or shells, which the young skimmer could not easily kick into the air. Conway and Bell (Living Bird, 7:57-70, 1968) describe Kittlitz Sandplovers (Cha- radrias pecuariiis) kicking sand over their eggs when disturbed. We have not found any reference which suggests the camouflage function for sand-kicking in young skimmers, but feel it is applicable. — Helen Hays, 14 East 95th Street, New York, New York 10028, AND Grace Donaldson, Department of Education, American Museum of Natural History, Central Park West at 79th Street, Netv York, New York 10024, 27 February 1969. March 1970 Vol. 82, No. 1 GENERAL NOTES 101 Barn Owls hunting by daylight in Siirinani. — In my “Birds of Surinam” (1968) I stated that the local race of the Barn Owl iTyto alba hellmayri) in Surinam is strictly nocturnal. Since writing this I have twice observed a Barn Owl hunting hy daylight. On 11 June 1967 I saw one at 11:00, in bright sunlight, (juartering the open and sandy savanna bordering the runway of the airfield at Zanderij. When the bird came nearby I collected it. It was a male in non-breeding condition and it had only a small lizard (Teidae) in its gizzard. Its weight was only 387 grams. Eleven other specimens from Surinam averaged 486 g (extremes 410-558 g). On 9 February 1968 at 10:00, once more in bright sunlight, 1 watched a Barn Owl hunting along the dam through a newly planted citrus plantation near Paramaribo. Three times it pounced down on the grassy roadside but it missed its prey each time. I am sure that it was chasing lizards which were numerous on the roadside. — F. H.wersciimidt, Wolfskmhtraat 16, Ommen, Holland, 29 March 1969. Food preferences of a hand-raised Blue Jay. — The kind of food that a Blue Jay ( Cyanocitta cristata) eats depends largely upon the kind available in a given locality at a particular time of the year ( Dyche, Trans. Kansas Acad. Sci., 21:130-137, 1908). Beal (USDA Yearbook 1896:197-206, 1897) examined 292 Blue Jay stomachs and Dyche (op. cit.) examined over 150 stomachs. Both authors agreed that approximately 24 per cent of the total yearly diet consisted of animal food (mostly arthropods) while 76 per cent was plant material (predominantly seeds and accessory structures). Good- Plant Products Cached Table 1 OR Eaten by RB 2 in Addition to Regular Diet. Plant & Plant Products Sampled Preference Plant & Plant Products Sampled Preference Peas 4-++ Coffee (cream) + Onions 4- Coffee (sugar) ++ Bean sprouts ++ Tea (any form) + All green vegetables + Carbonated soft drinks - Pineapple* - Beer (stale) +++ Banana + Beer (fresh) 4- Blueberries +++ Other alcoholic beverages - Raspberries ++ Candy & granulated sugar +4-+ Strawberries 4- Peanuts Cooked fruits & fruit desserts + Almonds ++ Oranges & orange juice +++ Acorns - Grapefruit & juice + All other nuts + Lemons & juice + Popcorn ++ Sweetened fruit juices -CP Potato chips ++ Pickle juice +++ Tobacco ++-P Coffee (black) - Paper** 4- Coffee (cream & sugar) -1-P+ Houseplants & cut flowers +T — = not eaten or cached -f- = eaten or cached infrequently when available 4 — j- = eaten or cached regularly when available 4 — I — j- = eaten or cached with great frequency when available * Whole pineapple.s were mobbed. ** Paper was eaten only when it accompanied a preferred item. 102 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 Table 2 Animal Products Cached or Eaten by RB 2 in Addition to Regular Diet. Meat & Animal Products Sampled Preference Meat & Animal Products Sampled Preference Beef, lamb, fish & fowl +++ Fats +++ Mild sausages ++ Soap (coarse-milled. Bacon, cooked & crisp +++ unperfumed) +++ Bacon, uncooked or soft + Soap (fine-milled. Spicy sausages & meats + perfumed) + Butter ++ Leather + Margarine + Dandruff ++ Milk — Cerumen ++ Eggs +++ Toothpaste ++ Egg shells +-H- Bee & candle wax + — = not eaten or cached + = eaten or cached infrequently when available +-i- = eaten or cached regularly when available d — I — |- = eaten or cached with great frequency when available win (Avicult. Mag. 59:122-133, 1953) observed that his captive Black-throated Jays {Garrulus lanceolatus) sampled a wide variety of plant and animal food offered to them. During a behavioral study of Blue Jays in 1962-1964, a hand-reared male Blue Jay (RB 2) kept at home was given a regular diet of canned dog food, cuttlehone, cooked chicken eggs, raw beef liver, live insects, an insectivorous bird mixture developed by Ficken and Dilger (Avicult. Mag. 67:46-55, 1961), French’s parrot mixture, cracked corn, peanuts, and suet. Since this bird was allowed to fly freely about the house, he was able to supplement his normal daily ration with food items not ordinarily available to jays in the wild, except perhaps those in picnic areas of parks. RB 2 sampled everything my family ate as well as a number of things we did not ordinarily eat (Tables 1 and 2). Some items were always eaten or cached by RB 2 when available and others were less regularly eaten or cached, and a preference order seemed to become established for the variety of items which were eaten. RB 2 seemed to recognize colors and shapes of wrappers and packages of his preferred items. If one regards RB 2’s feeding behavior as indicative of the feeding behavior of wild jays, one could infer that jays sample a very wide range of possible food sources, eating selectively from the items sampled and establishing definite food preferences. A. R. Weisbrod, Division of Biological Sciences, Cornell University, Ithaca, New York 14850, 17 March 1969. A ^ hite-throated Sparrow nest in western Pennsylvania.— The first nesting record for the White-throated Sparrow (Zonotrichia albicollis) in western Pennsylvania was made when I found a nest containing 2 eggs in McKean County on 13 July 1968. Todd (Birds of western Pennsylvania, 1940) recorded summer sight records from 1929 to 1937 at Hearts Content in Warren County, in northwestern Crawford County, and twice at Pymatuning Swamp in Crawford County. A nest was found in the Ohio part of Pymatuning Swamj) in 1932, an area since flooded liy^ a reservoir. It was reported to be casual in summer near Dubois and “may breed occasionally.” On a map showing sum- mer records of the White-throated Sparrow in Pennsylvania, Poole (Pennsylvania birds— an annotated list, 1964) indicated these localities listed by Todd as implied nestings. March 1970 Vol. 82, No. 1 GENERAL NOTES 103 The nearest previous nesting record for Pennsylvania was in Sullivan County in north- eastern Pennsylvania, about 110 miles from the new locality. The nearest nesting locality in New \ork is about 60 miles north at Java Lake Bog, Wyoming County, where two adults and two young were found (Beardslee and Mitchell, Birds of the Niagara frontier region, 1965) . The McKean County locality is a swamp of some 60 to 100 acres in the center of the county. The swamp lies in a broad, shallow basin on the unglaciated plateau at an ele- vation of 2,100 feet, and is predominantely a shrub swamp with little or no marsh or bog, although sphagnum moss is widespread. Among the most abundant shrubs are arrow-wood {Viburnum recognitum) , wild raisin {Viburnum cassinoides) , black choke- berry (Aronia melanocarpa) , and low sweet blueberry {Vaccinium august if ol iuni) . Hem- lock [Tsuga canadensis) is the most abundant tree species. Many of them are small and have a peculiar, dense, closely-sheared appearance resembling krummholz. The nest had been built at the base of a clump of wild raisin surrounded by a patch of low sweet blueberries 2 to 3 feet in diameter, and all of this was raised about 6 inches above the surrounding sphagnum. There was a large clump of small hemlock trees nearby, and an open stand of shrubs and small hemlocks in other directions. The nest was made almost entirely of fine grasses or sedges. The outside diameter was about 3.5 inches, the inside diameter 2.4 inches, and the depth of the cavity 1.5 inches. The 2 eggs were pale bluish and heavily spotted with brown. There were fine markings on the small end, hut the large ends were nearly solid brown with a few dark purplish marks. They mea- sured 20.2 X 16.5 millimeters. Tliis probably represents a second nesting, considering the very late date ( Lowther and Falls in Bent, U.S. Natl. Mus. Bull. 237, 1968). The population of White-throated Sparrows in this swamp has been fairly consistent with a minimum of 5 or 6 pairs each summer since 1965, when I found the colony. Other species found here in summer include several of the more common birds with northern affinities such as the Hermit Thrush {Hylocichla guttata), Canada Warbler {Wilsonia canadensis) , and Slate-colored Junco {Junco hyemalis) and the scarcer Nashville Warbler iVermivora ruficipilla) . — Ted Grisez, 8 Belmont Drive, JVarren, Pennsylvania, 24 March 1969. THE JOSSELYN VAN TYNE MEMORIAL LIBRARY During the past year gifts have been received. From: Reeve Bailey — 3 bulletins Richard C. Bjorklund — 1 reprint William H. Burt — 29 journals, 9 reprints John Cheek — 2 reprints Frank B. Gill — 3 books, 4 reprints Leonora Gloyd — 1 reprint F. N. Hamerstrom, Jr. — 1 hook, 26 re- prints Emmet Hooper — 1 reprint David W. Johnston — 2 books, 26 reprints, 1 translation Leon Kelso — 1 hook, 3 translations S. Charles Kendeigh — 5 reprints Peter H. Klopfer — 9 reprints Robert C. Lasiewski — 1 reprint Douglas M. Lay — 15 reprints Alice Miller — 26 books, 24 journals, 20 reprints, 32 wildlife prints Margaret M. Nice — 1 bulletin, 4 reprints Olin S. Pettingill, Jr. — 1 hook William Russell — 1 hook Helmut M. Sick — 5 reprints Robert W. Storer — 2 journals, 43 reprints, 1 report Harrison B. Tordoff — 2 journals Lars von Haartman — 1 hook, 2 reprints John E. Willoughby — 215 journals Martha S. Wilson — 1 l)ook Larry Wolfe — 2 reprints Howard F. Young — 6 reprints ORNITHOLOGICAL NEWS Ernest Mayr, of Harvard University, was one of the six distinguished scientists, and the only biologist, awarded the National Medal of Science for 1969 hy President Richard M. Nixon. The Society’s First Vice-President, Pershing B. Hofslund was awarded the Thomas Sadler Roberts award for contributions to Minnesota ornithology by the Minnesota Ornithologists’ Union. Members planning on attending the annual meeting in Colorado may be interested in the recent publication: “Birds in Western Colorado,” an annotated field list and travel guides for finding the best birding spots obtainable from the Historical Museum and Institute of Western Colorado, 4th and Ute Streets, Grand Junction, Colorado 81501. $1.75. The hack cover of this issue of The Bulletin gives some information about the annual meeting, and should he read carefully hy all those who might feel that Colorado is a distant location for the meeting. The opportunity of meeting with our sister society, the Cooper Society is one that many of us have looked forward to for some time. The ornitho- logical attractions of the region are most enticing, and your Editor, who has spent parts of 8 summers in Colorado, will testify that the many other attractions of the state are equally inviting. THE ring’s index ornitiiologorum The editor of the International Ornithological Bulletin THE RING proposes to publish an Index Ornitiiologorum embracing the professional and amateur ornithologists of the world. All entries should be in English and should he accompanied by one International Postal Reply Coupon for further correspondence. Closing date for all entries is June 30, 1970, hut earlier arrival of entries would he appreciated. Do not delay — send your entry to-day. The address is: The Editor, THE RING, Laboratory of Ornithology, Sienkiewicza 21, Wroclaw, Poland. An entry (in English) should contain the following information: 1. Surname 2. Names in full 3. Year of birth (optional) 4. Title 5. Positions held (including editorships, memberships, etc.) 6. Principal interest in ornithology 7. Address 8. Authors of ornithological publications are requested to ([uote the most important of them. 9. Do you intend to purchase a copy of the INDEX if reasonably priced? 10. One I.P.R. Coupon is enclosed: yes — no. Date. Signature. 104 ORNITHOLOGICAL LITERATURE Peregrine Falcon Populations: Their Biology and Decline. Edited by Joseph J. Hickey. University of Wisconsin Press, Madison, 1969: 6'/j X 914 in., xxii + 596 pp., 32 pages of photos. $10.00. The difficulty of reviewing this work can he briefly summarized hy noting the fact that the hook consists of 32 individual articles, nine discussion sections, and 12 brief reports on other raptors. It is the proceedings of an international conference held in the fall of 1965 to discuss the unprecedented decline of the Peregrine during the previous decade. Rapid publication of a conference of this type is difficult, due to the large number of contributors; in this respect this work compares unfavorably with the proceedings of the International Ornithological Congresses. This is to be regretted in such a rapidly developing field as the relationship of wildlife to environmental change. However, some of the most significant findings to 1968 have been added to the discussion. The first 280 pages are devoted to population studies of the Peregrine. In Alaska and British Columbia no change in the Peregrine population has been found. This is probably true for the northern Canadian population, estimated at 7,500 pairs, although detailed data are lacking. In the western United States the population has been seriously reduced and the species has been extirpated from the eastern United States. In Europe the decline has been most severe in the northern and central areas. The current Finnish population being only a few percent of their former numbers. In West Germany a decrease of 77 percent between 1950 and 1965 was noted. In the British Isles an unprecedented decline started in the mid 1950’s but the population has now apparently stabilized at a low level. In France the Peregrine has been extirpated in Normandy and severely reduced elsewhere. The continued success of the species in Spain, only briefly noted in the conference, is the one bright spot in Europe. No information is presented for Russia or southeastern Europe. The conference discussed a wide range of possible explanations for the decline. This can he divided into two parts, a slow long-term decline due to the encroachment hy man and a rapid decline over wide areas starting in the early 1950’s. The rapid decline in various areas had at least some of the following characteristics in common: (1) failure to lay eggs, (2) reduced clutch size, (3) egg breaking and eating, (4) failure to re-lay after loss of initial clutch, (5) embryonic mortality, and (6) some nestling mortality. Hickey and Roelle conclude (p. 565) that “The ecological case against the chlorinated hydrocarbon insecticides as the pervasive factor in these phenomena is essentially com- plete.” While this view is a fair summary of the viewpoint of the conference, some of the inconsistencies of the data are discussed at length hy Stickel in Chapter 42. Nor are other possible factors neglected. Pathogens, parasites, and predation are discussed hut no evidence for these factors causing a serious widespread decline was found. The plates are well chosen to show nest sites and habitats. Many are, I believe, not previously published although the editor was unable to resist the inclusion of the most famous Peregrine photograph of all — A. A. Allen’s Peregrine at Taughannock. Repro- duction is adequate but not first class. The figures are well drawn and the index excellent. Typographic errors appear to he few, although I had difficulty in deciding what I had done on elucidating the mechanism of change of calcium metabolism (p. 564). On the subject of style, one can say little since so many contributors are involved. The term “decimating factors” referring to the northern Canadian population is surprising, considering the apparent stability there. Decimating means literally the 105 106 THE WILSON BULLETIN March 1970 VoL 82, No. 1 killing of every tenth individual. Would that the eastern population of the I eregiine had merely been decimated! In view of the enormous interest in oil in Alaska, one imagines that there is no prospect of Cade’s visionary idea (p. 504) of the setting aside of a wilderness area coming to pass. Future generations will regret that his suggestion for the minimum requirement for preservation, “the setting aside of the entire Arctic Slope of Alaska as a wilderness refuge and the restriction of any permanent human habitation north of the Brooks Range” including the entire upper Yukon drainage system, was not acted on. Not only ornithologists but all persons interested in conservation are in Hickey s debt for his work on this conference and its proceedings. The value of examining changes of the environment on a greater than national basis are clearly shown. — David B. Peakall A Distributional Survey of the Birds of Honduras. By Burt L. Monroe, Jr. Orni- thological Monographs No. 7, American Ornithologists’ Union, 1968: 458 pp., 2 col. pis., 28 text maps. $9.00 ($7.20 to A.O.U. members). This is the first comprehensive distributional account of Honduran birds. Hitherto Honduras has lacked even an adequate check-list, although zoogeographically the country is one of the most complex and interesting in Central America. The interior is believed to date hack to Palaeozoic times, constituting part of “nuclear” Central America, which was separated from South America by water gaps in Nicaragua and Panama during most of the Tertiary. Since then many South American humid forest species have spread northward, but encounter an ecological filter barrier in the arid interior valleys and in the puzzling pine savannas of the Caribbean coast. These pinelands, of uncertain origin, have fostered an extension into the tropical lowlands, south to Nicaragua, of several temperate North American species, which farther north in Middle America inhabit highlands. The last check-list for Honduras (Stone, 1932) listed 410 species. My own Middle American list (1955), based largely on published records, attributed 585 species to Honduras, 11 of which Monroe, very properly, doubts or rejects. He accredits 663 species to Honduras, including the Swan Islands. One may question the inclusion of the avifauna of these islands, some 200 km out in the Caribbean, as an integral part of that of Honduras — considering the fact that the United States has long exercised jurisdiction as sovereign. But the species added consist only of a few West Indian endemics and migrants from the north. Although not stated, this work is essentially Monroe’s doctoral dissertation at Louisiana State University. Judging by literature references to 1966, some subsequent changes were made. Monroe collected in Honduras from 2 August 1962 to 13 May 1963, and from 30 March to 19 April 1964; he also had available specimens obtained by other field parties from his university. The most important material studied consisted of the vast collections made by the professional collector, C. F. Underwood, between 1931-1938, numbering well over nine thousand skins, scattered in various museums. Monroe checked most of Underwood’s birds, including those in the United States and in the British Museum, as well as significant collections made by others. With this material, his field experience, and his investigation of the literature, Monroe has been able to provide a better picture of bird distribution in Honduras than is presently in print for the neighboring countries of Guatemala and Nicaragua. He points out that Honduras is still perhaps the least known country in Central America and that several areas have not been worked at all or very superficially. Much of this rugged country is devoid of roads Maicli 1970 Vol. 82. No. 1 ORNITHOLOGICAL LITERATURE 107 and accessible only with difficulty. Some taxonomic problems involving distribution will require for their solution detailed field studies concentrated on particular species. Ilut Monroe provides a good start. The work is carefully organized. Two color plates by his university colleagues, S. A. Gauthreaux, Jr. and J. P. O’Neill, adorn the book. There are many helpful text maps. An introduction emphasizes the zoogeographic importance of Honduras, reviews recent additions to the known avifauna, and indicates areas particularly needing ornithological exploration. Then follows treatment of geology, soils, climate, and habitats. For habitats Monroe adopts essentially the nomenclature of Carr (1950) ; my only question here is the inclusion under “rain forest” (the wettest forest class) of areas with as little rainfall as 80 inches per year. A section entitled “History of Honduran Ornithology” includes, inter alia, not only Monroe’s itinerary, hut a useful summary of Underwood’s travels. The central and major part of the book consists of individual species accounts. Under a species heading, with scientific binomen and English name (based on Eisenmann, 1955, or the A.O.U. Check-List, 1957), are listed Honduran specimens examined, giving number, locality, sex, date, and institution where housed; then additional published locality records. A paragraph or two summarizes Honduran distribution, habitat, and status. Where appropriate this may be followed by a comment on taxonomy at the species or genus level. A final paragraph “Geographic ’V^ariation” discusses the subspecies to which Honduran specimens should be attributed, not infrequently rejecting a described race. At the end of the book are interesting accounts of migration, an analysis of the avifauna by habitat and by presumed origin, a gazetteer, a bibliography, and an index. Monroe intentionally has restricted this book to systematics and distribution, giving very little data on behavior, life history, or details of ecology. He has thus been al)le to devote considerable space to discussion of taxonomy at the species and subspecies level. I do not feel competent to appraise the question of Honduran subspecies; but, on the species level, generally I find myself in agreement, and where my present opinion may differ, the case admittedly is a controversially uncertain one. As Monroe has been exceptionally careful in regard to nomenclature, it may be appropriate to call attention to a few such matters. The original spelling of the sub- specific name of Cypseloides rutilus brunnitorqiies ( Lafresnaye) , which is used liy Peters and Zimmer, should be maintained; the emendation, “brunneitorqaes,'’ formerly often seen, is not warranted by the Code. I share Monroe’s objection to the recently suggested transfer of this name from the Colombian form to the west Mexican race (long known as griseifrons) , on the basis of re-identification of an ancient, faded, mounted specimen. Monroe’s rejection on the ground of nomen oblitum of the proposal (Deignan, 1961; Phillips, 1962) to supplant the well-known Chaetura richmondi Ridgway by “Chaetura. similis Salvin and Godman,” is correct, but can be rejected for a more basic reason, that it is not an “available” name under Code, Art. II (d), as has been pointed out by Wetmore (1967). Following all authors since Stone • 1897), including Ridgway (1902) himself, Monroe has treated the original spelling of the subspecific name Stiirnella magna inexspectata Ridgway (1888) as a lapsus for inexpectata. R. W. Dickerman has kindly called to my attention that, according to Latin dictionaries, either spelling was correct, hence no lapsus justifying emendation (a)uld be assumed. Nevertheless, the fact that Ridgway himself in his major work (1902) in- tentionally adopted .Stone’s emendation is evidence that the original spelling was in fact inadvertent; the same uniform usage by others for seventy years justifies its maintenance by Monroe. Monroe accepts Stein’s specific division of the Ernpidonax Iraillii complex, and (following Stein) uses the name E. breivsteri Oberholser for the populations which 108 THE WILSON BULLETIN March 1970 Vol. 82. No. 1 call ‘^filz-bewr For reasons to be detailed elsewhere, I believe that (regardless of specific or subspecific status) Audubon’s name traillii belongs to the Arkansas prairie population, which is a ^^fitz-bew” vocalizer, and cilnorum Brewster to the northern “/ee-tee-o” singers. On many controversial matters of taxonomy, Monroe has not hesitated to express his opinion, sometimes in unequivocal terms, hut at least he has given his leasons. He explains his philosophy, which he states will cause him to he regaided as a splittei at the generic and specific levels and a ‘"lumper” at the subspecific level. Actually he has done no new splitting in this hook, but merely rejected some recent proposals for lumping genera and species. His conservative approach will not endear him to those ornithologists who are sensitive about the sinking of their subspecies or who feel strongly about theii taxonomic views. As an author of a distributional work has to select the scientific name to use, he is forced, at least to that extent, to make a taxonomic decision in controversial cases. The systematic investigation necessary to determine local subspecies usually is feasible in a regional study, but when it comes to taxonomic problems at the generic or species levels whose determination may require going far beyond the area treated, most authors dealing with local distribution feel it the safer course to rely on some published authority. Monroe not infrequently indicates that he has exercised a personal judgment; one cannot help wondering in certain cases how he had the time to investigate adequately the extra-Honduran material during the course of a Ph.D. study. Nevertheless, it should be said that his treatment of controversial genera and species is almost always in accord with that of the major neotropical taxonomists, Hellmayr, Peters, or Zimmer, and usually of all three. However, two cases are worth mentioning where, while Monroe may well prove to be right in his conclusions, he seems to me to oversimplify a problem whose satisfactory solution requires further fieldwork outside of Honduras. These cases warrant discussion, because Monroe’s treatment, while deviating from that of most recent authors, is adopted in the recent Volume 14 of the “Check-list of Birds of the World” (1968), of whose section on Parulidae, Lowery and Monroe are authors. In agreement with Slud (1964), Monroe has removed the Buff-rumped Warbler, fulvicaiida group, from the genus Basileuterus to Phaeothlypis, a genus erected by Todd (1929). In appearance, song, general behavior, and habitat, as Monroe indicates, tbis complex differs strikingly from other Middle American species assigned to Basileuterus. But the generic situation in South America, not here discussed, makes more dubious tbe recognition of Phaeothlypis. The South American rivularis group, found east of the Andes, which Todd expressly kept in Basileuterus, and excluded from his genus Phaeothlypis by the diagnosis provided, is so like the fulvicauda group in appearance and habits that all current authors regard the two as strictly congeneric, and many as conspecific. At most they are allopatric semispecies. As Monroe includes rivularis in Phaeothlypis, should not a new diagnosis be supplied of the enlarged genus that will separate it from Basileuterus? But the case is still more difficult. There are one or two other South American species that seem in appearance, and, judging from the literature, in behavior, and style of song, to bridge the gap between the rivularh-fulvicauda super- species and the more “typical” members of the genus Basileuterus. This is frankly indicated in footnotes in the Check-list of Birds of the World (1968, vol. 14, p. 75) ; so what are the distinguishing characters of Phaeothlypis? Monroe merges Basileuterus delattrii with its more northern ally B. rujifrons, suggesting that ihey intergrade through salvim. (which most authors have regarded as a race of B. rujifrons). On morphology this seems an acceptable treatment, and was adopted by Ridgway, but subsequently both Todd (1929) and Griscom (1932), with more material, insisted that the distribution in Guatemala showed overlap without intergradation. As March 1970 Vol. 82, No. 1 ORNITHOLOGICAL LITERATURE 109 Monroe attributes all Honduran specimens to nominate delatirii, they conlriliute little to solution of the problem. Admittedly (as earlier pointed out by Dickey and van Rossem), Todd’s supposed “generic” character of wing/tail ratio does not hold, but there are color differences that distinguish B. delatirii from the B. rufifrons group and may serve as specific characters if there is sympatry. Quite possilily the seeming overlap in Guatemala may be explicable by something other than sympatry, but that will require fieldwork there. The statement that the allied forms “are essentially allopatric and intergrade over a wide area in eastern Guatemala” imports a demonstrated fact, rather than an opinion as to probabilities. In this connection it should be noted that the traces of white below the auriculars reported in a few Honduran delatirii do not necessarily indicate introgression of salvini genes, for the same traces are often found in the distant subspecies B. d. mesochrysus, all the way to Colombia. These comments are not intended to discourage expression of opinion ( a keen mind like Monroe’s may have sound insights even on scanty data), but rather to encourage additional investigation of an open problem that might otherwise seem to be solved. Anyone interested in the distribution and taxonomy of neotropical birds will find this a useful and stimulating (and sometimes controversial) book. If we had as con- scientiously and competently prepared works for all countries of Middle America, the task of those preparing the next A.O.U. Check-List of North American Birds would be greatly facilitated. — Eugene Eisenmann. The Audubon Illustrated Handbook of American Birds. By Edgar M. Reilly, Jr. 0. S. Pettingill, Jr., Editor in Chief. Sponsored by the National Audubon Society; published by McGraw-Hill Book Company, New York, 1968: 8% X 11% in., xvii + 524 pp., 31 col. pis., c. 400 bl. and wh. photos, 100 drawings. $25.00. This “handbook,” which weighs almost five pounds, hardly fits my dictionary’s definition, “a small hook . . . for guidance.” It is, instead, a heavy compendium covering all the birds that regularly occur in the United States and Canada, including Greenland, Alaska, and Hawaii. It also treats, but usually in less detail, extinct birds, introduced species, and accidentals for which specimen records exist: a grand total of nearly 875 species. After a brief introduction, the book takes up each family in A.O.U. Check-list order, the Hawaiian forms interspersed with the North American. The families are introduced by a brief summary of their characteristics: body sizes, general plumage types, geo- graphical ranges, breeding data, interesting extralimital forms, etc. This general summary is then followed by a separate account of each species in that family. Some birds are covered by a short paragraph or two, hut most are given a more thorough treatment, organized hy seven topic headings: appearance, voice, range and status, habitat, seasonal movements, biology, and suggested reading. Well over 500 of the species are illustrated by photographs or drawings. When an author sets out to discuss some 875 species in 505 pages, approximately one- half of which are filled by illustrations, his text must necessarily be written in a very condensed style. In most instances Reilly has done this very well. The least successful cases are in the plumage descriptions; they are very uneven, some too short (the Common Loon is given only five lines, and the adult breeding plumage is not descrilied) and others overly long (McCown’s Longspur rates 20 lines of painstaking description). A few are simply poor or confusingly worded (Brown Pelican) but the majority are 110 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 probably adequate for the space available. The voice descriptions are also spotty, some good, others inadequate in light of present knowledge. Reilly often fails to identify the behavioral implications of sounds, although they are generally available in lecent literature: which vocalizations are territorial song, which alarm notes or distiess calls, etc. Range (including extralimital) and status are described in considerable detail, much more than in most field guides. In places the very condensed geographical short- hand (“P.E.I.” and “c.Mack.,” for example) may be confusing to readers not used to this sort of thing, but it usually can be deciphered through adjacent, more familiar, abbreviations. The remarks on status are often very useful, but not always current; the figure given for Whooping Cranes is 33 in 1963. By far the most valuable aspects of the book are the sections on seasonal movement, habitat, and Ijiology. These contain information that is not usually in field guides and may be difficult to find without a sizeable reference library. Even if a reader has extensive library facilities available, it is extremely convenient to have migration times, habitat preferences, and such aspects of basic biology as number and color of eggs, incubation periods, fledging ages, and number of annual broods for all North American birds brought together in one volume. In the weeks I have had this book, I have used it often for this kind of information. Reilly has been very careful in bis compilation of data not to gloss over those aspects of avian biology that are not known. He clearly points out gaps in our knowledge of American birds and it is hoped that readers may fill these in as opportunities arise. 1 am sure that many facts, particularly incubation periods and fledging ages of some of our commonest birds, remain unrecorded simply because few people realize they are yet to be determined. Overall, it is clear that this book has been painstakingly researched and compiled. It is a monumental collection of information, and as such, the author may be justly proud of the almost complete lack of factual errors therein. One of the few mistakes I spotted was the statement that only (adult) male Cedar Waxwings bear “the waxy scarlet tips on the smaller feathers of the wing”; adult females also occasionally have well-developed “wax” tips, and I have even seen small bits of red in the juvenal plumage. Probably the greatest fault of the book lies in its writing style. Although it is encyclopedic in nature, and perhaps not meant to be read througb like a book with a narrative, it is nevertheless exceedingly dull reading. Time after time I noted the omission of an interesting bit of information or mention of current exciting research that might have given the book some life. People study birds because they find them interesting; this compilation will offer facts about birds, but very little of what is fascinating about them. The book also contains a large number of inconsistencies and small annoyances. Reilly lists the (editorial office) addresses of the three main American bird journals, but with no indication that these are temporary; indeed, two were out of date when the book was published (the A.O.U. in Lawrence, Kansas, and the Cooper Society in Berkeley, Cali- fornia). The Introduction states that the ranges will l)e given from west to east, and then the first one (Common Loon) is given east to west. Some of Reilly’s discussions of family affinities are puzzling and need explanation, particularly such statements as “ [swallows! are probably most closely related anatomically to the larks, thrushes, and weaver birds.” And throughout the sections on Suggested Reading there is a lack of references to modern literature. Surely something more recent than John Burroughs’ “Wake-Rol)in” (1871) could have been found for the Hermit Thrush? Two papers on the mating behavior of the Sage Grouse (Auk, 1940 and 1942) are the only references for Marcli 1970 Vol. 82. No. 1 ORNITHOLOGICAL LITERATURE ]T1 that species, missing the comprehensive monograph l)y R. L. Patterson in 1952. OI)vious (and commendable) effort was made to keep to standard or easily-oljtained literature, l)ut exceptions occur (e.g., the title for the Greater Prairie Chicken is a Uni- versity of Missouri publication) so there is no excuse for not including important references where they are pertinent and comprehensible to the general reader. Primary among the inconsistencies, however, are the uneven treatments within and among certain species. To my mind there is too much general emphasis on “unusual” birds — accidentals and species with very restricted ranges. This may he an attempt to give better coverage to species that are usually omitted altogether from North American hooks, but it leaves this book out of balance. I cannot see why the White Ibis, a common enough bird in the southeastern states, is dismissed in only eight lines as “Essentially a white-plumaged Glossy Ibis . . .,” which it is not; yet the introduced Spotted-breasted Oriole found only in the Miami, Florida region, deserves 29 lines. Sutton’s Warbler, he it a hybrid or full species and on the Hypothetical List of the A.O.U. Check-list, is still in many of the field guides and deserves some mention, if only as an ornithological will-o’-the-wisp; both Brewster’s Warbler and Lawrence’s Warbler are described under one of the parental species. The Red-whiskered Bulbul, the only member of the Pycnonotidae within the range of this hook, also occurs only around Miami, yet it has an entire (half-empty) page to itself. If this and the other “exotic” families were to he included in the book, they certainly (perhaps especially) deserved illustration; yet even where there is plenty of room for a photograph, none has been supplied t Pycnonotidae, Timaliidae, Cotingidae, Zosteropidae) . It also seems a great shame that when an author has gone to such obvious pains to write in a space-saving style, tbe composers could not have honored his efforts by adjusting the illustrations and text so as not to leave quite so many half-blank pages. The photographs are, for the most part, adequate but undistinguished. The Jagana looks as though it is a mounted specimen, but others (notably passerines at their nests) are quite nice. The printing process, however, is such that the “black and white” illustrations lack crispness, coming out in varying shades of fuzzy gray. They cannot compare with the excellent reproduction quality in Brown and Amadon’s “Eagles, Hawks and Falcons of the World” published recently by the same Audubon Society-McGraw-Hill coalition, and selling at a comparable price per volume. The colored photographs are variable, some very poor, but others good. The Black-necked Stilt settling over its eggs with its incubation patch in full view is particularly interesting, but curiously no mention is made of this in the caption or the text. The Cinnamon Teal is dreadful, being apparently of wing-clipped birds, and in garish color. I should have thought that when using only 31 color plates in a book of this price, better photographs could have been selected. Again, in comparison with Brown and Amadon, the present book suffers badly. In summary, this “handbook” is a compilation of the basic knowledge on North American and Hawaiian birds. Careful attention has been given to accuracy of detail, and therefore it will be a valuable reference book for years to come. It is unfortunately rather dull to read, and has numerous inconsistencies, particularly in balance of treatment between and among species. It is, however, easy to use and should be both comprehensible and useful for the beginning student. Technical terms and jargon have been successfully avoided, and it is adequately indexed. The Handbook seems to have been designed for the bird watcher who wishes to go beyond his Peterson guides, but is not yet ready to invest in a set of Bent’s Life Histories or other detailed references. With the low (]ualily of illustration reproduction, however, I question whether it is a bargain for anyone at .'$25. — Mahy Heimerdinger Clench. 112 THE WILSON BULLETIN March 1970 Vol. 82, No. 1 Handbucii der Vogel Mitteleuropas. Volume 1. Gaviifoimes Phoenicopterifoimes. By Kurt M. Bauer and Urs N. Glutz von Blotzheim. Edited by Gunther Niethammer. Akadeniische Verlagsgesellschaft, Frankfurt am Main, 1966: 6 X 9^/4 in., 483 pp., many bl. and wh. illus., 14 maps. Price not given. This first book of a proposed eleven-volume series, has grown out of the old German classic, ‘’Handbook of German Ornithology,” a three-volume work hy Niethammer (1937, 1938, and 1942). The original coverage has been expanded both in terms of geography aird content. Now encompassing central Europe, the text has additional headings such as “behavior” and “survey of the population” under each species treated. Completely dropped from the old text is the subject of parasites. The book is org anized in much the same way as Palmer’s “Handbook of North American Birds” and this first volume likewise brackets the same taxonomic span: loons through flamingos. The most obvious shortcoming of this handbook is the paucity of maps. There are only 14 used as aids in summarizing banding returns, distributions and migration routes. Even very small distributional maps as found, for example, in Robbins, et ah, “Birds of North America” could have heen put to good advantage and saved much verbiage. Even a map of the area covered by this hook — i.e., central Europe — would have been most helpful. This area roughly takes in the Netherlands, Belgium, Luxembourg, Germany, Switzerland, Austria, Czechoslovakia, and Hungary. Another deficiency exists under the heading of vocalizations. The sounds are given in phonetic syllables. The limited value of this method is at once apparent when it is encountered in a language other than one’s own. Furthermore, I should think that “quarrark quarrark gwo gwo” conveys a limited amount of information even to one who speaks German. This space might better have gone to audiospectrographic representation of the vocalizations. The sections on behavior are done especially well with generous illustrations. Another valuable feature is the extensive reference material presented both at the beginning of the hook and throughout the text. In the introduction is a bibliography of the birds of the world organized hy regions, as well as references listed under general avian topics as reproduction, food, migration, etc. In determining the need for such a book, the authors consulted not only their colleagues but potential laymen users as well, and so they included such items as simplified keys to orders, families, genera, and species. This concise book is not only an important reference for those interested in European ornithology but it also, at a glance, points out the gaps in our avian Kenntnis and thus, as Niethammer observed, this and following volumes will undoubtedly stimulate further research. — Sam E. Weeks. ANNOUNCEMENT Tlie Office of -Science and Technology has released a report entitled “Systematic Biology— A Survey of Federal Programs and Needs,” obtainable from Superintendent of Documents, Washington, D.C. 20402. Price: .$1.2.5. This issue of The Wilson BaUetin was published on 20 March 1970 Editor of The Wilson Bulletin GEORGE A. HALL Department of Chemistry West Virginia University Morgantown, West Virginia 26506 Editorial Advisory Board William C. Dilger Andrew J. Meyerriecks Douglas A. James Robert W. Nero William A. Lunk Kenneth C. Parkes Glen E. Woolfenden Ornithological Literature Editor Olin Sewall Pettingill, Jr. Laboratory of Ornithology, Cornell University, Ithaca, N.Y. 14851 Suggestions to Authors Manuscripts intended for publication in The Wilson Bulletin should be neatly type- written, double-spaced, and on one side only of good quality white paper. Tables should be typed on separate sheets. Before preparing these, carefully consider whether the material is best presented in tabular form. Where the value of quantitative data can be enhanced by use of appropriate statistical methods, these should be used. Follow the AOU Check-list (Fifth Edition, 1957) insofar as scientific names of United States and Canadian birds are concerned unless a satisfactory explanation is offered for doing otherwise. Use species names (binomials) unless specimens have actually been handled and subsequently identified. Summaries of major papers should be brief but quotable. Where fewer than five papers are cited, the citations may be included in the text. All citations in “General Notes” should be included in the text. Follow carefully the style used in this issue in listing the literature cited; otherwise, follow the “Style Manual for Biological Journals” (1964. AIBS). Photographs for illustrations should be sharp, have good contrast, and be on gloss paper. Submit prints unmounted and attach to each a brief but adequate legend. Do not write heavily on the backs of photographs. Diagrams and line drawings should be in black ink and their lettering large enough to permit reduction. Authors are requested to return proof promptly. Extensive alterations in copy after the type has been set must be charged to the author. Notice of Change of Address If your address changes, notify the Society immediately. Send your complete new address to the Treasurer, William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. He will notify the printer. The permanent mailing address of the Wilson Ornithological Society is: c/o The MUSEUM of Zoology, The University of Michigan, Ann Arbor, Michigan 48104. Persons having business with any of the officers may address them at their various addresses given on the back of the front cover, and aU matters pertaining to the Bulletin should be sent directly to the Editor. PLAN TO ATTEND THE 1970 ANNUAL MEETING The 1970 meeting of the Wilson Ornithological Society will be held jointly with the Cooper Ornithological Society at Colorado State University in Fort Collins from Wednesday, 18 lure to Sunday, 21 June 1970. The meeting is being sponsored jointly by Colorado State University and the Colorado Field Ornithologists. The chairman of the local committee for arrangements is Dr. Ronald A. Ryder, Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80521. The program chairman is Dr. Keith Dixon, Department of Zoology, Utah State University, Logan, Utah 84321. Detailed information concerning accommodations, transportation, and a call for papers will be sent to all members with advanced registration forms. Reasonably priced food and lodging will be available in modern dormitories within a block of the Student Center. Good facilities and activities are planned for families. Approximately 75 species of birds should be available at this season in the vicinity of Fort Collins. Field trips will be made to nearby Rocky Mountain National Park where one can observe such species as White-tailed Ptarmigan, Brown-capped Rosy Finch, Water Pipit, Clark’s Nutcracker, Gray Jay, Steller’s Jay, Common Raven, Blue Grouse, Northern Three-toed Woodpecker, and Pygmy Nuthatch. Trips will also be made to the Pawnee Site of the Inter- national Biological Program’s Grassland Biome Study east of Fort Collins where Mountain Plovers, McCown’s and Chestnut-collared Longspurs as well as large numbers of Colorado’s state bird, the Lark Bunting nest. Golden Eagles, Prairie Falcons, Ferruginous Hawks, Swainson’s Hawks, and Burrow- ing Owls also nest in the vicinity. White Pelicans, Double-crested Cormorants and various herons can be observed nesting at other locations in northcentral Colorado. JhcWsonBulkttn PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W. VA. VOL, 82, No. 2 JUNE 1970 PAGES 113-240 The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President — William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. First Vice-President — Pershing B. Hofslund, Dept, of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812. Second Vice-President — Kenneth C. Parkes, Carnegie Museum, Pittsburgh, Pennsylvania 15213. Secretary — Jeff Swinebroad, 8728 Oxwell Lane, Laurel, Maryland 20810. Treasurer — William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. Elected Council Members — Andrew J. Berger (term expires 1970) ; C. Chandler Ross (term expires 1971); Ernest P. Edwards (term expires 1972). Membership dues per calendar year are: Sustaining, $10.00; Active, $5.00. Life memberships, $150 (payable in four installments). The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new books; members and friends are invited to maintain the fund by regular contribution, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 104 periodicals as gifts and in exchange for The Wilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer (small sums in stamps are acceptable). A complete index of the Library’s holdings was printed in the September 1952 issue of The Wilson Bulletin and newly acquired books are listed periodically. The Wilson Bulletin The official organ of the Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Morgantown, West Virginia. The subscription price, both in the United States and elsewhere, is J6.00 per year. Single copies, $1.50. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at $1.50 each) and may be ordered from the Treasurer. Special prices will be quoted for quantity orders. All articles and communications for publications, books and publications for reviews should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library. Museum of Zooloev Ann Arbor, Michigan. ’ Second class postage at Lawrence, Kansas, U.S.A. 66044 Allen Press, Inc., Lawrence, Kansas 66044 THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society VoL. 82, No. 2 June 1970 Pages 113-140 CONTENTS The Habits and Relationships of the Magellanic Woodpecker Lester L. Short 115 The Pomarine Jaeger as a Brown Lemming Predator in Northern Alaska W illiam ] . Maher 130 A Population Estimate of the Dusky Seaside Sparrow Brian Sharp 158 An Investigation of Territorial Behavior in the American Redstart Utilizing Recorded Songs Roy A. lakes and. Millicent S. Ficken 167 The Winter Territories of Tufted Titmice Ralph W . Condee 177 Food Habits and Feeding Behavior of the Baltimore Oriole in Costa Rica Richard L. Timken 184 En Route Behavior of Homing Herring Gulls as Determined by Radio-Tracking William E. Southern 189 Molt and Taxonomy of Red-breasted Nuthatches Richard C. Banks 201 A Comparative Study of the Foods of the Sora and Virginia Rail Gerald J. Horak 206 A New Turkey from the Pliocene of Nebraska Larry I). Martin and Janies Tate, Jr. 214 General Notes CfjNjoiNED TWIN darwin’s riiea - - Doiuild Briining 2V) A SWIMMING BALD EAGLE Theoclore R. Merrell, Jr. 220 SHARP-TAILED GRHUSE GIVES AGGRESSIVE DISPLAY TO AUTOMOBILES Robert If . Nero 221 HING-BILLED GULL ANU LAUGHING GULL CATCH FISH BY ‘'BLOUGHING AND KaH Eric Tolonen SKIMMING A PUTATIVE SKELETAL SPECIMEN OF THE FLAMMULATED OWL MHIII ALABAMA Glen E. Wooljenden LOCALITY DATA THE DOUBLE-SCRATCH IN THE SEASIDE SPARROW Frank Enders NEST-BUILDING, INCUBATION PERIOD, AND FLEDGING IN THE BLACK-CHINNED HUMMINGBIRD Salome Ross Demaree ACTIVITY OF MIGRANT THRUSHES AS DETERMINED BY RADIO-TELEMETRY Charles G. Kjos and William W. Cochran FIRST SPECIMENS OF CHESTNUT-COLLARED LONGSPUR AND LITTLE GULL FROM CONNECTICUT Walter Bulmer CIRCLE-SOARING BY MIGRATING NIGHTHAWKS Helmut C. Mueller METHOD OF SEARCHING FOR FOOD BY THE SWAINSON’s WARBLER BrOoke Meanley RUFOUS-CROWNED TANAGERS FEEDING ON FRUITBOWL F. Haversclimidt 222 223 225 225 225 226 227 228 228 Ornithological News 229 Ornithological Literature ^^9 Leslie Brown and Dean Amadon, Eagles, Hawks and Falcons o] the W orld, re- viewed by Kenneth C. Parkes; Crawford H. Greenewalt, Bird Song: Acoustics and Physiology and How Birds Sing, reviewed by William W. H. Gunn; C. Clayton Hoff and Marvin L. Riedesel . Short THE MAGELLANIC WOODPECKER 120 THE WILSON BULLETIN June 1970 VoL 82, No. 2 Fig. 5. Edge of mature Nothofagus forest northeast of Lake Lolog, 18 kilometers north of San Martin de los Andes, Neuquen. Magellanic Woodpeckers were abundant in this forest (see text). Note the dead tops of many trees on the slopes. Cattle were pastured in the foreground (where scattered bamboo clumps are seen), but not in the forest itself. TAPPING AND DRUMMING Sounds produced by the Magellanic Woodpecker’s bill against wood are of two general types, tapping associated with feeding, and that serving a signal function. 1 he latter may be the functional equivalent of “drumming ’ in other woodpeckers (e.g., species of Dendrocopos, Dryocopus, Colaptes, etc.), and is hence designated the “drum-tap.” I apping associated with feeding is variable in intensity, frequency and duration, depending upon the foraging site and the food being sought. There is no single means of feeding (see above). The sounds produced by a forag- ing Magellanic Woodpecker range from barely audible scraping noises (like those of a nuthatch, Sitta) to loud, repetitive taps. In the former case feeding is by probing; in the latter case, it is by the delivering of hard blows with the bill. I was unable to detect a difference in tapping between foraging individuals of Dendrocopos lipnarius and those of Magellanic Woodpeckers feeding in smaller branches of trees. In those instances when large (about 10 cm in diameter ) pieces of bark were chopped out of a Nothofagus tree Lester L. Short Fig. 6. The interior of the mature Nothofagus forest shown in Figure 5. Amid the large trees with draped mosses and a bamhoo understory is the nest cavity (in pale- barked tree above bamboo, left center) of a pair of Magellanic Woodpeckers. I the birds tapped loudly, and deliberately, usually at one to four blows in a I series. The sounds of these blows are easily distinguished from drum-taps : by their irregular pattern, lesser resonance, and (usually) lesser intensity. I Drum-taps were heard most frequently from one pair near a nest. These loud, hollow-sounding taps were produced by double or (occasionally ) single blows against a tree. They may have been directed at me as an intruder I near the nest. The drum-tap may serve in the establishment and maintenance of territories, and perhaps also as a location note for members of a pair. The drum-taps of the Magellanic Woodpecker are like those of Fhloeoceasles robustus (Fig. 9), which I heard in northeastern Argentina. Other species of Phloeoceastes {P. melanoleucos, personal observation; P. giialenialcnsis, Slud, 1964; P. leucopogon, Wetmore, 1926), and Campephilus [C. princi- palis, Tanner, 1942; probably C. iniperialis, see Nelson, lo9o:221) have very similar drum-taps; indeed, these may characterize all campephiline species. VOCALIZATIONS Despite the brief time spent observing Magellanic Woodpeckers, several vocalizations were heard and recorded on tape. Other vocalizations prob- THE MAGELLANIC WOODPECKER 122 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 ably remain to be described, and further study of those which are discussed below is necessary to ascertain their functions. The vocalization uttered most often by the Magellanic Woodpeckers we observed is a variable, double-noted, harsh call, similar to that of Phloeoceastes rubricoUis described by Snyder (1966:161) as an “explosive, nasal ngkah- ngkah.’ ” Lrom two to five of these double-noted calls were given in each sequence. I noted variants of this call as follows: pi-cad; wieeeer; kee-adh (softer, less harsh); kee-drgh (harsher, more drawn out); and kee-yew (second note less emphatic). The call was emitted by lone individuals, apparently directed at me or elicited by my presence. It was employed also by males and females comprising groups of three or four birds observed 20-23 November at 18 km north of San Martin de los Andes. Here it appeared to be an agonistic vocalization utilized in encounters, but it may also function as an alarm call. The significance of the variation in this call is unknown, although it presumably is related to the various levels of motivation of birds uttering the call. Another call heard only from the pair of birds studied extensively can be designated the toot call. This is somewhat similar to the kent call of Campephiliis principalis (Tanner, 1942), but it lacks the nasal quality of the latter (interestingly, the entire known vocal repertoire of C. principalis is comprised of nasal, trumpet-like notes ) . Single toot notes were heard occasionally from members of the pair as they were feeding. These might function as location notes, but they were also emitted in series of two or three notes, often leading into a burst of pi-cad calls, by the adult birds near their nest. In one sequence of calls near the nest the male emitted a series of four toot calls, followed by five or six pi-cad calls, and these in turn were followed by a drum-tap (see above). These notes may have been directed at me. I heard these woodpeckers utter only two other types of vocalizations. One of these is a low peep call heard only near a nest occupied by a single nestling. While I was not certain that the young bird produced this note, it seems likely. The peep calls were interspersed with pi-cad calls emitted by one or both adults. 4 his situation may have been the result of my presence; the calling young bird may have been hungry, and the disturbed adults may not have been feeding it a sufficient amount of food. Another call, heard only once, was a loud, prolonged cray-cra-cra-cra-cra-ci'a, given by a lone male clinging to a tree about 70 m from me. 4be bird flew off shortly after it called. Prolonged calls of this nature function in other woodpeckers (e.g., species of Dendrocopos and Colaples; personal observation) in the establish- tnent and defense of territory, but the lone instance of this call in the Magellanic Woodpecker provides no basis for speculation regarding its function. Lester L. Short THE MAGELLANIC WOODPECKER 123 DATA FROM SPECIMENS Various data were obtained from 16 specimens that we collected, includ- ing one unfeathered nestling and 15 adults. Many of these were prepared as alcoholic specimens and skeletons for anatomical investigations. The adults examined generally had irides colored pale yellow near the pupil, progressively becoming gold, and finally orange, away from the pupil. One bird had irides uniformly yellow, but with flecks of orange scattered throu2,hout. Most of the adult specimens, collected from 20-29 November, had not yet commenced breeding. One female (collected on 20 November) had laid an egg; its ovary measured 20 X 10 mm, and a brood patch was present. Six other females had ovary measurements of from 8x5 mm to 15 X 11 mm. One of the latter had slightly enlarged ova (to 2 mm) and an incipient brood patch, another had a defeathering brood patch, and a third female showed slight enlargement of the oviduct. The single nestling was obtained on 29 November. Weights of seven adult males ranged from 312 to 363 g, with an average of 338.4 g. Six females weighed from 276 to 312 g, averaging 291.3 g. A female laying eggs weighed 326 g. A brood patch was evident in only three of seven males that were collected, including the mate of the female that had laid an egg. These brood patches were not completely formed. The testes of six of these males measured from 4 X 2 mm to 10 X 8 mm. The sole nestling was prepared as an alcoholic specimen, and few data aie available for it. The essentially featherless, two or three day old bird was alone in a nest cavity ( described above ) ; its weight was 29.6 g. A COMPARISON OF THE EXTERNAL MORPHOLOGY OF THE MAGELLANIC WOODPECKER WITH OTHER CAMPEPHILINE WOODPECKERS dhe Magellanic Woodpecker is a large picid exceeded in size among the woodpeckers only by several species of the genera Campephilus, Dryocopus, and Mulleripicus. Like the other eampephiline woodpeckers this species has a (moderately) broad bill, and the inner two pairs of its rectrices are especially hard and stiff. Among the eampephiline woodpeckers the Magellanic Woodpecker is usually considered a close relative of the North American ivory-billed woodpeckers (Campephilus principalis and C. imperialis, which probably comprise a superspecies; see Fig. 7). It approaches them in size, and in its white wing patches, which are visible when the bird is perched; the curled crest of the female is also like that of the female of C. imperialis. Ho wever, there are numerous differences between the Magellanic Woodpecker and the northern ivory-bills. 124 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Fig. 7. From left to right are adult pairs of Magellanic Woodpecker iCampephilus magellanicus) , Imperial Woodpecker (C. imperialis) and Ivory-billed Woodpecker ( C. principalis) . The male of each species is at the left, and the female at the right. 1 he Magellanic Woodpecker has a large white wing patch restricted to the inner web of the secondaries and the basal portion of the inner vane of the primaries; the primaries are never tipped with white. In contrast, the northern ivory-bills have white over the entire distal portion of all secondaries, and white progressively restricted from the inner to the outer primaries toward their tips and not their bases. This renders the flight pattern of these birds entirely different. Like Phloeoceastes guatemalensis and P. melanoleiicos (see Ligs. 8, 9) and the Pileated Woodpecker { Dryocopus pileaius), the Magellanic Woodpecker exhibits a single, anterior, white underwing patch, because the white in its flight feathers is continuous with that of the under- wing coverts. I he northern ivory-hills exhibit two white wing patches, an anterior patch formed by the white coverts, and a posterior white patch separated from it by the black bases of the flight feathers (^see Tanner, 19-12:2). I he Magellanic Woodpecker has relatively narrow, tapered outer (tenth) piimaiies, hut the northern ivory-hills have even narrower, strongly falcate outei ]>iimanes. The rectrices of the Magellanic Woodpecker are less sturdy than aie those of its northern relatives, and the second rectrices often exhibit so much weal that the central rectrices stand apart from them; these two Lester L. Short THE MAGELLANIC WOODPECKER 125 Fig. 8. From left to right are a male Cainpephilus iPhloeoceastes — see text) guate- malensis, a female of that species, a female Magellanic Woodpecker, and a male and female of Campephilus leucopogon. pairs of rectrices are equal in the northern ivory-bills. The bill of the Magellanic Woodpecker is black, never ivory in color like the bills of C. imperialis and C. principalis, which are also relatively sturdier, more massive and broader (more wedge-shaped from a dorsal view) than that of C. jnagellanicus. Indeed, the bill of the Magellanic Woodpecker is proportion- ally less massive than that of several species of Phloeoceastes (especially P. leucopogon, Fig. 8). This is particularly reflected in the weak ridge on the gonys of Campephilus magellanicus, as compared with C. imperialis, C. principalis, Phloeoceastes leucopogon, P. melanoleucos, and P. robustus. The bill size difference between tbe sexes of C. magellanicus was discussed above; this difference is greater than that occurring between tbe sexes of C. principalis and C. imperialis. The male Magellanic Woodpecker has an all-red head and a rather short crest, matched among carnpephiline woodpeckers by Phloeoceastes giiate- malensis. The female typically has a long, curled crest resembling that of the female of C. imperialis. Some species of Phloeoceastes such as P. leucopogon, P. melanoleucos and P. guatemalensis, have males with essentially all-red 126 THE WILSON BULLETIN J line lyTO Vol. 82, No. 2 Fig. 9. From left to right are a female and a male of Campephilus melanoleucus, a female Magellanic Woodpecker, and a male and female of Campephilus robustus. heads, including the crest, and females with a crest that is black anteriorly and red posteriorly. The black crest feathers of these females are usually more elongate than the red feathers (sometimes red feathers are longer, but, if so, they have black tips ) . These black crest feathers occasionally curl somewhat forward (specimens of P. leucopogoji and P. melanoleucos) . I suggest that differential wear of black and red feathers may have been a factor in the evolution of the crests of these species, for melanin-containing feathers appear to be more durable and resistant to wear than are red feathers. The evolution of the three large species of Campephilus has been marked by reduction or elimination of red in the female’s crest and head pattern. In the northern ivory-bills the females have entirely lost their red coloration of the head, and their long crests are black. The males of these two species have a reduced amount of red in the crest; essentially they have assumed the female head pattern of Phloeoceastes melanoleucos and P. guatemalensis. However, males of the northern ivory-bills have the red feathers of the crest longer than the black ones. The head pattern of the Magellanic Woodpecker has developed differently. The female of this species has a reduced amount of red, which occurs around the bill (the only other campephiline species the Lester L. Sliort THE MAGELLANIC WOODPECKER 127 females of which have red in this region is Phloeoceastes guatemalensis ) , and a curled black crest. However, reduction of red coloration has not occurred in the male. Instead, the latter has an all-red head like that of Phloeoceastes guatemalensis and P. leucopogon ( the latter has a longer crest, however ) . The Magellanic Woodpecker resembles Phloeoceastes ruhricollis and differs from all other campephiline species in the absence of white on its back and neck. Ventrally, most specimens show some evidence of white at the tips of the abdominal feathers. A few individuals have most abdominal feathers with white tips. This condition gives a somewhat barred appearance to the abdomen, perhaps reflecting such a pattern in the ancestors of C. magellanicus. No other campephiline species with black underparts (C. imperialism C. prin- cipalis, Phloeoceastes leucopogon ) exhibits this white barring. COMMENTS ON RELATIONSHIPS OF CAMPEPHILINE WOODPECKERS The Magellanic Woodpecker has been considered to comprise a monotypic genus [Ipocrantor Cabanis and Heine), or to be congeneric (in Campephilus Gray) with the northern Imperial and Ivory-billed Woodpeckers. I believe that the Magellanic Woodpecker is not related directly to the northern ivory- hills, but rather is related to them indirectly by virtue of the independent evolution of both groups from species of Phloeoceastes Cabanis. The simi- larities between the Magellanic Woodpecker and the northern ivory-bills (e.g., tendency toward a falcate outer primary, longer gonys, plumage patterns; see above ) seem to be the result of parallel evolution of large woodpeckers from the same basic ancestral stock of Phloeoceastes. Other similarities among the three large “ivory-bills” (e.g., vocalizations, color pattern, tail structure; see above ) are shared with various species of Phloeoceastes. On the other hand the differences (see above) between the Magellanic Woodpecker and the northern ivory-billed group appear to reflect their recent independent evo- lutionary history. I he “generic” characters setting Campephilus and Ipocrantor apart from Phloeoceastes (chiefly their more falcate primaries and longer gonys, Ipo- crantor being intermediate in the latter respect between Campephilus and Phloeoceastes', see Ridgway, 1914:9-10) are trivial and possibly correlated with the larger size of these birds. In any event, species groups within Phloe- oceastes (these groups are: the P. leucopogon-guatemalensis-melanoleucos- guayaquilensis group; the P. robustus group, probably including P . rubri- collis; and the P. haematogaster-pollens group) seem at least equally as distinct as Campephilus and Ipocrantor. The recognition of the latter two genera seems to necessitate the splitting apart from Phloeoceastes of at least two genera (‘‘‘‘Cniparchus,” ‘"‘‘Scapaneus'' ', for their characteis see Ridgway, 1914) for taxonomic consistency. 128 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 The various groups of campephiline species, including the Magellanic Woodpecker group and the northern ivory-bill group, can he accommodated within a single genus { Carnpephilus ) comprised of 11 species. These species are so fundamentally similar in coloration, structure and habits that their inclusion in one genus far better expresses their relationships than does splitting them into two genera { CampepJiilus and Phloeoceastes this would he incorrect, as the species of Campephilus are not strictly monophyletic ) , three genera { Campephilus, Ipocrantor, and Phloeoceastes) , five genera I the three last mentioned, Cniparchus and Scapaneus) or even more genera (e.g., including Megapicos Malherbe). Hence, I follow Bock (1963) in consider- ing the campephiline woodpeckers to comprise the single genus Campephilus. SUMMARY The large Magellanic Woodpecker {Campephilus magellanicus) inhabits the Nothofagus forests of southern South America, where only one small species of woodpecker { Dendrocopos lignarius) is a sympatric potential competitor. In the virtual absence of competition the Magellanic Woodpecker forages in diverse ways and at various sites. The sexes differ in bill length (almost no overlap between sexes), probably correlated with a difference in feeding habits. Nesting sites vary, as may the size of the clutch. The breeding season in southwestern Argentina commences in November. Drum-tapping is generally like that of other campephiline species for which data are available. Vocaliza- tions resemble those of the Ivory-hilled Woodpecker {Campephilus principalis) and other campephiline species (e.g., Phloeoceastes rubricollis) . The Magellanic Woodpecker shows certain morphological similarities with the northern ivory-hilled species (Campe- philus principalis and C. imperialis) , hut also many differences which suggest that these two groups of woodpeckers independently evolved from ancestral species of Phloeoceastes. It is suggested that the Magellanic Woodpecker and the northern ivory- hills comprise hut two of five groups of campephiline woodpeckers, no group of which is sufficiently distinct to merit separate generic recognition. Accordingly, the 11 species of campephiline woodpeckers are considered congeneric (genus Campephilus) . ACKNO\VLEDGMENTS 1 thank Richard S. Crossin and Francisco Espinola for assistance rendered in the field, and authorities of the National Science Foundation for support of my field studies in Argentina (N.S.F. grant G.B.-5891). Martin Morton and Roxie C. Laybourne kindly providcd data from specimens at the Moore Laboratory of Zoology of Occidental College, and the United States National Museum, respectively. Mrs. Use Atkinson was helpful in facilitating our field woik around .San Martin de los Andes, Argentina. LITERATURE CITED Ashmole, N. 1 . 1967. Sexual dimorphism and colonial l)reeding in the woodpecker Centurus striatus. Amer. Naturalist, 101:353-356. Dock, W. 1963. Evolution and phylogeny in morphologically uniform groups. Amer. Naturalist, 97:265-285. Bock, W. and W. de W. Milleh. 1959. The scansorial foot of the woodpeckers, with comments on the evolution of perching and climbing feet in birds. Amer. Mus. Novitates, no. 1931. Lester L. Sliort THE MAGELLANIC WOODPECKER 129 Johnson, A. W. 1967. The birds of Chile and adjacent regions of Argentina, Bolivia and Peru. Vol. II. Platt Establ. Graficos, Buenos Aires. Kilham, L. 1965. Differences in feeding behavior of male and female Hairy Wood- peckers. Wilson Bull., 77:134-145. Ligon, J. D. 1968. Sexual differences in foraging behavior in two species of Dendrocopos woodpeckers. Auk, 85 :203-215. Mayr, E., E. G. Linsley, and R. L. Usinger. 1953. Methods and principles of system- atic zoology. McGraw-Hill Co., New York. Nelson, E. W. 1898. The Imperial Ivory-billed Woodpecker, Campephilus imperialis (Gould). Auk, 15:217-223. Peters, J. L. 1948. Check-list of birds of the world. Volume VI. Harvard Univ. Press, Cambridge. Ridgway, R. 1914. The birds of North and Middle America. Part VI. U.S. Natl. Mus. Bull., 50. Selander, R. K. 1965. Sexual dimorphism in relation to foraging behavior in the Hairy Woodpecker. Wilson Bull., 77:416. Selander, R. K. 1966. Sexual dimorphism and differential niche utilization in birds. Condor, 68:113-151. Selander, R. K. and D. R. Giller. 1963. Species limits in the woodpecker genus Centurus (Aves). Bull. Amer. Mus. Nat. Hist., 124:213-274. Slud, P. 1%4. The birds of Costa Rica. Bull. Amer. Mus. Nat. Hist., 128. Snyder, D. E. 1966. The birds of Guyana. Peabody Mus., Salem, Mass. Tanner, J. T. 1942. The Ivory-billed Woodpecker. National Audubon Soc., Res. Report 1, New York. VuiLLEUMiER, F. 1%7. Pliyletic evolution in modern birds of the Patagonian forests. Nature, 215:247-248. Wetmore, a. 1926. Observations on the birds of Argentina, Paraguay, Uruguay, and Chile. U.S. Natl. Mus. Bull., 133. THE AMERICAN MUSEUM OF NATURAL HISTORY, NEW YORK, NEW YORK 10024, 27 MAY 1968. THE POMARINE JAEGER AS A BROWN LEMMING PREDATOR IN NORTHERN ALASKA William J. Maher The population fluctuations of many arctic predators, both avian and mam- malian, are associated with changes in the numbers of their major prey, the several species of arctic lemmings. Pitelka, Tomich, and Treichel (1955a) reported that the breeding densities of avian predators near Barrow, Alaska from 1951 to 1953 were correlated with lemming abundance. Their work confirmed that the Pomarine Jaeger [Stercorarius pomarinus) is a major lemming predator in northern Alaska and documented qualitatively the relationship of this species with the popula- tion cycle of the hrown lemming (Leimnus trirnucronatus) in that region. They also pointed out the desirability of quantifying the relationship between the two species. Accordingly the major objective of my study was an attempt to define the relationship between the populations of the Pomarine Jaeger and the brown lemming quantitatively, in order to determine the role of avian predators in the lemming cycle. In this paper I will discuss the food habits, nesting density, and reproductive success of the jaeger population and try to assess the impact of their predation on the hrown lemming population. The interactions of populations in a simple system involving a single prey species and several avian predators should contribute to understanding of predator- prey relationships in general, in addition to the specific question of the role of predation as a possible cause of the lemming cycle itself. My study was conducted for five seasons in northern Alaska through a com- plete lemming cycle, beginning with a high lemming population in 1956 and terminating with a second lemming high in 1960. Most of the field work was done at Barrow, although data were also obtained at Pitt Point, Wainwright, and Cape Sabine ( Fig. 1 ) . Additional observations were made in 1954 and 1955 when I was employed at Barrow by the U. S. Geological Survey. I was at Barrow briefly in the summer of 1953 and witnessed the lemming high of that year. ENVIRONMENT Barrow is at the northern tip of Alaska at approximately 70°N. Latitude. It is at the apex of a wide triangular coastal plain that is 100 miles from east to west and oO miles fiom north to south at its widest longitude through Barrow (Fig- 1)- This papei is concerned with the portion of the coastal plain within which the brown lemming population cycles regularly, as well as with a coastal strip 130 Mailer ^ POMARINE jaeger predation on brown lemming J 3 ] Fig. 1. Map of northern Alaska with place names mentioned in the text. usually less than five mile wide, extending from Gape Sabine on the West to Oliktok Point on the east, within which the brown lemming population fluctu- ates irregularly. The portion of the coastal plain within which lemming highs regularly occur is triangular and extends 80 miles east and west of Barrow and 25 to 30 miles inland at its widest point south of Barrow. The environ- mental description applies to the area thus defined. The northern part of the north Alaskan coastal plain is a region of low re- lief, extensive marshy areas, meandering streams, and numerous lakes and ponds. The development of mature drainage has been impeded by the level topography and by underlying permafrost. Twenty per cent of the area is cov- ered by lakes ( Spetzman, 1959) and more than 50 per cent is covered with standing water (Black and Barksdale, 1949). The vegetation of this region, as of tundra generally, is low. The vegetation on mesic and wet sites at the end of the growing season averages ajiproximately six inches in height. The vegetation on dry sites is lower, and on a few favour- able wet sites it can be several inches taller. Marsh areas dominated by Carex species, especially Corex aqualilus, cover approximately one-third of the land area under consideration (Thompson, 19556 ). Marsh usually occurs on a saturated peat substrate, often with one to three inches of standing water. Marsh vegetation occupies the saucer-like de- pressions of low-center polygons (Thompson, op. cit.) as well as extensive marshes in partly drained lake basins and around the edges of ponds and lakes. Elevated drier sites typically contain a poorly developed tussock-heath tundra association (Britton, 1957 and Spetzman, 1959). This association is 132 THE WILSON BULLETIN J une 1970 Vol. 82, No. 2 essentially a simple mat of sedges and grasses with a minor element of pros- trate willow shrubs, heath species, mosses and lichens. Eriophorum vaginaturn, which further inland forms large tussocks, is here reduced in stature and in- conspicuous. The most common heath elements are Ledum groenlandicum, V accinium vitis-idaea, and Cassiope tetragona. The climate of the arctic coast of Alaska is severe. Winters last nine to ten months and are cold. Summers are short and cool. The average annual tem- perature at Barrow is 10.1°E. The mean temperature for February, the cold- est month, is -18.1 °F, and for July, the warmest month, it is 40.0°F. The mean minimum temperature is above freezing from late June to early August. The tundra is free of snow for the latter part of June, July, August, and early September. Frost is possible in all months. The mean annual precipitation averages 1.1 inches at Barrow. The sun is above the horizon continually for 87 days from 9 May through 4 August. Cape Sabine is in the northern foothills of the Brooks Range where they reach the coast (Fig. 1). The study area, about one mile inland, is characterized by long parallel rocky ridges separated by broad shallow swales. The vegeta- tion is much more complex than in the portion of the coastal plain described above. Well developed tussock-heath tundra covers the slopes and luxuriant Carex marsh occurs in the swales. Marsh vegetation here is dense and is 14 to 16 inches tall by mid-July. The Pomarine Jaegers which bred in the area nested in the swale bottoms. BACKGROUND A review of the recent history of the brown lemming population in northern Alaska, and some information on lemming biology and predator biology are necessary for understanding the spatial and temporal aspects of the breeding ecology of the Pomarine Jaeger. The brown lemming population of northern Alaska has been studied con- tinuously since 1949. Details of population fluctuations and other aspects of lemming ecology are in Rausch (1950), Thompson (1955a, 1955/>, 1955c), and Pitelka (1957a and 19576 ). Lemming highs are characteristic of coastal tundra in northern Alaska (Pitelka, 1957a), and seem to he confined to the northern portion of the coastal plain, already described, where, as a result of climatic modification by the arc- tic ocean, the tundra vegetation is simpler than tundra inland. Two lemming species occui in this aiea, the brown lemming and the collared lemming {Dicrostonyx groenlandicus) . The latter species is relatively rare and locally distiihuted, so that the brown lemming is the only significant microtine rodent in this coastal area. Sr" ^ POMARINE JAEGER PREDATION ON BROWN LEMMING ] 33 Up to the termination of this study in 1960 general lemming highs were ob- served in northern Alaska in 1949, 1953, 1956, and 1960. A general, moderate lemming population occurred in 1952, and low populations occurred in 1950, 1951, 1954, 1955, 1957, 1958, and 1959. In 1956 maximum lemming density occurred in a triangular area of 1,200 to 1,500 square miles extending south from Barrow 25 miles to the Inaru River, east 60 miles to Cape Simpson, and west 70 miles to Peard Bay. About the periphery of this area was a region of lower population density which was approximately ten miles wide on the western and southern edges hut extended 30 miles eastward of Cape Simpson nearly to Pitt Point (Pitelka, 1957a). In 1960 the western and southern borders of the lemming high were approximately the same as in 1956; but, lemmings were scarce in the area be- tween Admiralty Bay and Cape Simpson and east to the Ikpikpuk River. East- ward from there to Oliktok Point there was a moderately high lemming popu- lation occupying a narrow region along the coast. The extent of the 1960 high was also estimated to be 1,200 to 1,500 square miles. Accurate information on the extent of the 1953, and 1949 highs is not available. The evidence suggests that they were confined to the area of the 1956 high. There were two localized highs of Lemmus in northern Alaska in 1957 in areas peripheral to the main area discussed above and out of phase with it. The more extensive of these was centered at Pitt Point approximately 80 miles east of Barrow. Its exact extent was not determined; hut it Avas known to occupy the tundra between Teshekpuk Lake and the Arctic Ocean. Its western boundary was near Longitude 153°45' W. It did not reach the Kogru River (Longitude 152°30' W), but the eastern limits were not determined more pre- cisely. This lemming high occupied an area of 250 to 400 square miles. A second lemming high occurred in 1957, 90 miles west of Barrow at Wain- wright, and extended at least 5 miles inland on the east side of Kuk Inlet. Its extent was not otherwise determined. The tundra vole [Microtus oeconomus) occurs regularly as far north as the northern foothills of the Brooks Range and the southern coastal plain. In that area its population fluctuations are apparently restricted, but occasional local population highs are known to occur. A coastal population of this species co- existing with four other microtine rodents was studied at Cape Sabine from 1957 to 1959 ( Childs, 1959 ) . The Microtus population built up rapidly in the summer of 1958 and reached a high level at the end of that season. In the summer of 1959 the Microtus population was still high, and four pairs of Pomarine Jaegers bred there for the first time. I he extent of this high is not known, hut it appeared to he local and probably occupied less than 25 square- miles. 134 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 To summarize: In northern Alaska in 12 seasons from 1949 to 1960 wide- spread lemming highs occurred four times, a widespread moderate lemming population once, and the lemming population was low in seven seasons. In 1957 there were two local highs at Pitt Point and Wainwright. The interval between the general lemming highs since 1949 has been three to four years. The amplitude of the fluctuations is large, but lemming den- sity varies between peak years, and estimates of the magnitude of the fluctua- tion differ greatly. Thompson (19556) estimated that there was a 400-fold increase from the low of 1950 to the 1953 peak at Barrow. Krebs (1964) esti- mated a 25- to 50-fold increase in the winter preceding the 1960 lemming high at Baker Lake, N.W.T., and a two- to three-fold increase during that summer, following a brief decline at melt-off in June. Shelford (1943) estimated an increase of 800- to 1,000-fold in the lemming cycle at Churchill, Manitoba. Predators are not evident for two years following a decline from a high. Moderate numbers of lemmings are present either early or late in the third summer of a four-year cycle, and avian predators may exploit the third-year population if lemming density is high enough in the spring. Although lemmings, like other microtines, sometimes breed in the winter, at Barrow when the snow cover melts in June the lemming population consists mostly of nonbreeding adult animals. Synchronous breeding in the population begins immediately and a large summer generation of lemmings emerges in mid-July. Breeding continues through the summer, and the first summer litter may produce a second generation in August or September. Lor additional in- formation on the biology of the brown lemming in northern Alaska, the reader is referred to the papers of Rausch, Thompson, and Pitelka cited previously. Live species of avian predators may be associated with the lemming high. They are the Pomarine Jaeger, the Snowy Owl (Nyctea scandiaca) , the Para- sitic Jaeger {Stercorarius parasiticus) , the Short-eared Owl (Asio flammeus), and the Glaucous Gull ( Lams hyperhoreus ) . Significant mammalian predators are the least weasel {Mustela rixosa) and the arctic fox [Alopex lagopus). I his study was concerned with the Pomarine Jaeger, but an attempt will be made to assess the total predation impact on the lemming population. The breeding biology of the Pomarine Jaeger, in northern Alaska has been summarized by Pitelka, Tomich, and Treichel (19556 ). The Pomarine Jaeger is a model ately laige predator on its nesting grounds. Lemales collected in northein Alaska average 745 grams in weight and males 648 grams. Pomarine Jaegers anive on the tundra in late May and early June. In breeding years they establish laige all-puipose territories. The normal clutch of two eges is laid in an unlined sciape on the tundra in mid- to late June. The chicks emer^’e wuliam J. POMARINE JAEGER PREDATION ON BROWN LEMMING 135 Maher in mid-July and begin to fly in the last half of August. Adults and young depart in late August or early September. GENERAL METHODS Breeding jaegers are easily watched and censused because they are both conspicuous and aggressive and because tundra vegetation offers negligible interference with observation. At Barrow the study area was systematically traversed using a tracked vehicle, a weasel. Nests were staked, and the location of nests and territorial pairs was plotted on an out- line map traced from aerial photographs. By continually rechecking the location of nests in relation to neighboring nests and landmarks, considerable accuracy was eventually obtained in maps of nest distribution. In 1956 and 1960 the nests on part of the study area were mapped with an alidade and plane-table. Censuses were repeated regularly in the season to determine population trends and breeding success. In areas away from Barrow censusing was done on foot, and pair and nest locations were marked on aerial photographs carried in the field. The area censused differed between years depending on jaeger density. Thus, at Barrow in years of maximum jaeger density the study area was 5.75 and 6 square miles, while in years of low jaeger density about 15 square miles were censused. The size of the area studied is given with data on breeding density. For feeding and growth studies nests were encircled with a fence 30 feet long and 12 inches high making an enclosure about 9 feet in diameter. Nine nests were enclosed at Barrow in 1956, one in 1959, and 15 in 1960. One nest was enclosed at Cape Sabine in 1959. When nests were fenced during the incubation period the adults returned to the eggs in minutes and fed the chicks normally when they hatched. Chicks fenced after hatching usually died because the adults did not feed them properly. As jaeger chicks cannot jump, they were not able to escape from the enclosure until they could fly. The enclosed nests were visited at regular intervals, the chicks weighed with a beam balance, and regurgitated pellets and other food remains collected. Regurgitated food remains were softened in detergent and water. Jaws, skulls, femurs, and pelves of small mammals, all identifiable remains of birds, and all other food items were picked out. The residue was floated in water so that insect fragments and other small remains were recovered. The method of analysing the food remains depended on their condition. When pellets were intact, food items were recorded as the percentage of occurrence in the total number of pellets. When regurgitated food material was trampled or picked apart by the jaegers and individual pellets were not recognizable, food items were analysed as the occurrence in the total number of prey items. The numlier of lemmings and other vertebrate prey was the number of the most nuiuerous hone eleirrent, usually the right or left jaw of lemmings. Only the occurrence of food items such as insect remairrs and egg-shell frag- ments was recorded for each sample. Sex ratios of the pelves rerrroved from all pellets were detenrrined. Separation of nrale and female pelves more than 20 mm along the ilium-ischium axis on the basis of their shape is readily done on museum specimens ( Dunirrire, 1955). However, the rrrosl obvious difference between the nrale and female pelvis is the l)ackward extension of the pubis of the ferrrale which gives the posterior border of the pelvis a sloping contour rather than the rounded contour of the rrrale. This part of the female pelvrs rs thm and nrechanical action of digestion often breaks off the puho-ischial corner, causing the specimen to resemble a male pelvis. 136 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 The following criteria were used in addition to shape to distinguish the sexes. All pelves with a least pubic width of 0.7 min or less were considered female, and all with a least pubic width of 1.00 mm or more were considered male. This separation, based on the results of measuring pelves of 50 males and 50 female museum specimens, can be done with 2 per cent error. The 24 per cent of the pelves with least widths of 0.8 and 0.9 mm were classified on morphological grounds, or rejected if a comfortable decision could not he made. Two Pomarine Jaeger chicks were raised from hatching at the laboratory in 1960. Two partly grown chicks brought in from the tundra gave additional data on food consumption. The chicks were placed outdoors in a large cage, eight by eight feet by ten feet high at the age of eight and nine days. Hence they were exposed to natural ambient tempera- tures, and had much freedom of activity. Records were kept of their daily weight and food consumption. Systematic observations were made on frequency of feeding of breeding adults. In 1957 and 1958, nonhreeding jaegers along the ocean near Barrow and Wainwright were collected by Eskimos. The specimens were frozen at the Arctic Research Labora- tory, and processed at the end of the season for data on stomach contents, weight and reproductive condition. Further details on methods will be given where they are appropriate. RESULTS Food habits of the jaeger. — The Pomarine Jaeger utilizes a large variety of food on its breedings grounds, although most items occur rarely in its diet, and there are few foods which it obtains in quantity. The very specialized adaptations of the Pomarine Jaeger as a predator are apparent when a distinc- tion is made between the ability of the bird to obtain enough food for survival in nonbreeding years and its ability to feed itself and also raise a brood of chicks. Nonbreeding populations of Pomarine Jaegers were sampled at Barrow and Wainwright in the low lemming years of 1957 and 1958. The variety of food items in the sample of 56 stomachs (Table 1) suggests that this jaeger is largely opportunistic in its food gathering and takes anything available. Microtine rodents occurred in 41 per cent (23) of the stomachs, and birds were in 25 per cent (14) of them. Lour of five shorebirds were Red Phala- ropes [Phalaropus julicarius] and one was a calidrine sandpiper, either Erolia rnelanotos or E. alpina. Remains of large birds were mostly unidentified, but included one ptarmigan. Two of 11 bird eggs were Red Phalarope. Carrion included caribou ( Rangifer tarandus ) and one seal ( Phoca sp. ) . Marine in- vertebrates were unidentified squid, polycheate worms, and unidentifiable remains. It appears from this analysis that jaegers were foraging over the tundra, along the ocean shore, and in the native villages. Caribou and seal remains were probably found near the villages. The marine invertebrates were prob- Er ^ POMARINE JAEGER PREDATION ON BROWN LEMMING J 37 Food of Nonbueeding Table 1 PoMARiNE Jaegers, 1957 AND 1958 Number of Per cent Food items stomachs occurrence Microtine rodent 23 41 Avian 14 25 Carrion 8 14 Bird egg 11 20 Insect 5 9 incidental in stomach 3 5 predominant in stomach 2 3 Fish 7 12 Marine invertebrate 2 3 Number of stomachs 56 ably picked up on the beach as I have never observed jaegers robbing other birds of their food near Barrow and Wainwright, as has been frequently described by observers in temperate areas (see Bent, 1921). The only locality at which I did observe this behavior in northern Alaska was at Cape Sabine where there were a large number of Black-legged Kittiwakes {Rissa iridactyla) ; and even there it was uncommon. Breeding populations were sampled by analysing regurgitated pellets col- lected on the tundra at Barrow in 1956, 1959, 1960, and at Pitt Point in 1957. Pellets were also collected from chick enclosures at Barrow in 1956, 1959, and 1960, and at Cape Sabine in 1959. Pellets of the current season were distin- guished by dried mucus on their surface. Two of these five jaeger populations were of maximum density (Barrow, 1956 and 1960), one was moderately dense (Pitt Point, 1957), and two were very sparse (Barrow and Cape Sabine 1959). Microtine rodents make up the bulk of the food utilized by all of these populations regardless of their breed- ing density (Table 2). At Barrow and Pitt Point Lemmus is the predominant microtine, Dicrostonyx occurs very rarely. Microtus oeconornus was the ex- clusive microtine prey at Cape Sabine. Food other than microtine rodents is more than 10 per cent of the prey items only in the two sparse 1959 populations, in which it was 17 per cent at Barrow and 12 per cent at Cape Sabine. Birds were the most important prey category after microtine rodents. Bird remains consisted mostly of shorebirds. predominantly chicks, and a few ducklings and passerine birds. Remains of 138 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 2 Food of Breeding Pomarine Jaeger Populations Food item 1956 Barrow 1960 Pitt Point 1957 Barrow 1959 Cape Sabine 1959 Total niicrotine 98.6" 97.8” 100" 100" (83)” 88” Other food 8.5 2.2 3 27 (17) 12 Bird 0.9 1.9 1 9 ( 7) 12 Bird egg 1.2 3 2 12 (10) Fish 0.2 0.3 3 (3)" 5” Insect (incidental) 6.2 3 (3)" 2'= Number 432 2500 206 75 (89) 68 “ Per cent occurrence of food item in pellets. Per cent occurrence of food item in total number of food items. Number of occurrences in pellet samples; not included in total of prey items. large birds, such as ducks, occurred very rarely. Fish and insects are un- important and carrion, absent. It seems justified to compare these results with the data from nonbreeding jaeger populations even though they are based on food remains in regurgitated pellets and the latter sample is based on analysis of stomach contents. All prey items found in stomachs were identified by undigestable parts such as feathers and bone, and all (except marine invertebrates) have also been found in pellets. Furthermore, items such as insect fragments, insect eggs and otoliths are readily found in pellets when they are examined thoroughly (see methods ) . Nonhreeding populations utilized a much smaller proportion of microtine rodents and a larger proportion of birds than breeding populations did, and carrion and fish were significant components of their diet. Insects were most of the contents of three per cent of the stomachs, whereas they were always incidental in pellets of breeding populations. These results confirm the great importance of lemmings in the diet of breed- ing jaegers. The relatively low number of prey items other than lemmings, also suggests that breeding jaegers are dependent on lemmings (or other microtine rodents) for sufficient food for successful breeding. The food habits of nonbreeding jaeger populations confirm this conclusion. Lemmings are the most important prey these birds obtain on the tundra; yet the im- portance of carrion and fish in their diet suggests that they foraged along the coast because they could not obtain sufficient prey from the tundra to survive or attempt to breed. Jaeger breeding density and lemming density. — The fact that the Pomarine Jaeger is dependent on the lemming population for food poses problems of Mailer ^ POMARINE jaeger predation on brown lemming 139 adjustment of the jaeger population to a variable food supply. In order to maintain itself the jaeger population must exploit lemming populations ef- ficiently when they are at densities high enough to support the predator’s re- productive efforts. In any area, food will be adequate for jaegers in only one in three, or at best two in four years. The Pomarine Jaeger responds to the lemming cycle by adjusting the frac- tion of its population which breeds. This adjustment is locally manifested by fluctuation of the jaeger’s breeding density. The species cannot alter its clutch size in response to food supply as do many raptors, including the other major avian lemming predator, the Snowy Owl. Quantitative data on the total Pomarine Jaeger population are not available, but I would like to dis- cuss breeding density changes and reproductive success in relation to lemming numbers. The estimated density of Lemnius at the time of the snow melt-off is used to compare lemming densities between years, because this is a convenient, identifiable point at which to compare lemming populations, and because the jaegers are presumably responding to this initial number of lemmings when they begin breeding activities. The density estimates were made by Pitelka (Barrow) and myself (Barrow and Pitt Point) and are estimates with un- determined margins of error. The order of magnitude indicated by the dif- ference between years is certainly a correct one (Table 3) . Information on changes in nesting density and breeding success of Pomarine Jaeger populations was obtained at Barrow from 1954 to 1960, from Wain- wright and Pitt Point from 1956 to 1960, and Cape Sabine from 1957 to 1960. Spring lemming density estimates are only available from Barrow for all years and from Pitt Point in 1957. Information on jaeger breeding density and success in 1952 and 1953 are from Pitelka, Tomich, and Treichel (1955a). In the nine seasons from 1952 to 1960 at Barrow the Pomarine Jaeger did not breed in three (1954, 1957, and 1958), small numbers bred in two seasons ( 1955 and 1959) and significant numbers of Pomarine Jaegers nested in only four of the nine seasons ( 1952, 1953, 1956, and 1960) (Table 3) . Other areas show similar variations in the breeding density of the Pomarine Jaeger. At Wainwright breeding occurred in only three of the five years, and breeding density was low each time. Pomarine Jaegers bred in only two of five years at Pitt Point. In 1957 a moderately high density of jaegers nested in response to a local lemming high; and in 1960, when the general lemming high of that year extended eastward past Pitt Point, a low density population of Pomarine Jaegers bred. Pomarine Jaegers bred only once at Cape Sabine from 1957 to 1960, and then only in very low numbers. Comparison of spring lemming density with Pomarine Jaeger breeding 140 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 3 Breeding Densities AND Nesting Success of THE Pomarine Jaeger Locality Year Spring Lemmus density (no. /acre) No. of pairs Census area (square miles) Density (pairs/ square mile) Maximum density (pairs/ square mile) Breeding success (per cent of eggs) Barrow 1952 15-20 34 9 3.8 5-6’' 30-35“ 1953 70-80 128 7 18.3 25-26“ 20-25“ 1954 <1 0 — — — — 1955 1-5 2 15± 0.13 — 0 1956 40-50 114 6 19.0 22-23 4 1957 <1 0 — — — — 1958 <1 0 — — — — 1959 1-5 3 15± 0.20 — 0 1960 70-80 118 5.75 20.5 25 55 Wainwright 1956 3 2± 1-1.5 — ? 1957 3-4 4 1.0 — 9 1958 0 — — — — 1959 0 — — — — 1960 4-5 ? 2± — 9 Pitt Point 1956 0 — — — — 1957 30-40 61 6 10.1 15 13 1958 0 — — — — 1959 0 — — — — 1960 4-5 1-2 — — 9 Cape Saliine 1957 0 — — — — 1958 0 — — — — 1959 4” 11 0.36 13 1960 0 Estimates i^jrovidetl by F. A. Pitelka; see Pitelka, Tomich, and Treichel, 1955fi. This jaeger population nested in response to a high density of Microtiis oeconor?ius for which no density estimate is available. In suitable nesting habitat. density at Barrow shows a clear correlation between the two (Table 3). The Pomarine Jaeger does not breed at spring lemming densities estimated to be below one per acre. Some breeding takes place at densities of approximately one to five lemmings per acre. Pomarine Jaeger density increases proportion- ately with lemming density until the mean maximum jaeger density of 18-20 pairs per square mile is reached. Three lemming highs (19.53, 1956, and 1960) supported virtually identical mean Pomarine Jaeger densities near Barrow, though the magnitude of the lemming population peaks were different (Table 3, Lig. 2). The leveling of the Pomarine Jaeger’s response curve at Mailer" ^ POMARINE JAEGER PREDATION ON BROWN LEMMING ] 41 Fig. 2. Relationship between Pomarine Jaeger breeding density and the density of the spring brown lemming population. high lemming densities suggests that different factors limit the breeding den- sity of jaeger populations at high lemming densities than at low ones. Since the Pomarine Jaeger is strongly territorial and defends an all-purpose terri- tory ( Pitelka, Tomich, and Treichel, 1955a), territoriality appears to be the most likely mechanism limiting jaeger density. At jaeger densities below the maximum, food supply is probably limiting, but the question of how food supply acts to adjust Pomarine Jaeger breeding density is unanswered. The response may be related to different thresholds between young adults and more experienced breeders in the population. Fewer of the heavily striped jaegers, which are presumed to be younger individuals, are seen in the sparse breeding populations than are seen in the dense populations. Breeding success of jaeger populations. — The apparent adjustment of Poma- rine Jaeger breeding density to the lemming population level raises the ques- tion of the efficiency of the adjustment. The best criterion for judging its efficiency would seem to be the nesting success. If the adjustment of the jaeger’s breeding density were efficient at all lemming densities, it should re- sult in a relatively consistent level of reproductive success. In fact, reproduc- tive success has not been constant (Table 3). Breeding success has tended to he low at low nesting densities (Barrow, 1955 and 1959, Cape Sabine, 1959 ), and low to moderate at intermediate densities (Barrow, 1952 and Pitt Point, 1957). At maximum density, breeding success at Barrow has ranged from 142 THE WILSON BULLETIN J une 1970 Vol. 82, No. 2 Size Classes Table 4 I OF Lemming Femurs and Mean Lemming Weights per Class No. Size class ( mill ) N Mean wt. (g) Weight factor (g) 1 <10 2 8.4 8.0 2 10-15 77 24.8 25.0 3 15-19 8 64.8 65.0 4 >19 22 89.1 90.0 almost complete failure (1956) to moderate success (1953) to high success ( 1960 ) . The highest breeding success was achieved at high nesting densities. The maximum populations must contribute most of the recruitment to jaeger numbers, as their large areal extent suggests that they involve a large propor- tion of the total jaeger population. Yet, breeding success was dramatically different in the two dense jaeger populations at Barrow in 1956 and 1960. Success in those years was clearly related to food supply. In 1956 the lemming population declined during the season ( Pitelka, MS) and by late July was not sufficient to sustain the jaegers. Many of the chicks starved and those which did not die of starvation were killed by snow and cold weather on 9 and 10 August. The estimated four per cent success of total eggs layed is generous. In contrast, lemmings remained abundant all through the 1960 season (Pitelka, MS), and chick survival (55 per cent) was the highest recorded. The sparse breeding populations of the jaeger probably do not contribute significantly to recruitment because of the small fraction of the population which breeds and the low success usually realized. In years when few' jaegers breed, nonbreeding jaegers forage on the tundra singly or in large flocks. Breeding failure of jaegers frequently results from interference by these non- breeding birds, or by nonbreeding Snowy Owls. These data suggest that the territorial breeding system of the Pomarine Jaeger has evolved to enable the jaeger to limit its exploitation of high popu- lations of lemmings so that the probability of significant reproductive success is increased. Effect of jaeger predation on the leinining population. — Predators affect the numbers of the prey population directly by the number removed, and indi- rectly by altering the age and sex structure of the population and, hence, the futuie couise of its dynamics. Lour criteria were used to assess the impact of the Pomarine Jaeger on the brown lemming population. They are: (1) the size classes, and hence reproductive status of the removed population; (2) the number of prey taken; (3) the sex ratio of the removed population; and (4) Mailer"’ ^ POMARINE JAEGER PREDATION ON BROWN LEMMING 1 43 I960 Fig. 3. Size classes of lemming femurs in adult jaeger pellets (top) and penned jaeger chick pellets (bottom) in 1956 and 1960. the timing of the predator impact in relation to the annual population cycle of the prey. (1) Size classes of lemmings taken. — The impact of jaeger predation on the lemming- population can be partly assessed if -we know the age groups of the prey affected. Size is used here as an approximate indicator of age and reproductive status. The femurs were sorted into four arbitrary size classes (Table 4). The mean weight of each class was de- termined from skeletons of animals of known weight (Table 4). The size classes of lemmings taken early in the season are indicated by the frequency distribution of femurs from adult jaeger pellets from 1956 and 1960 (Fig. 3). Pellets were collected through the season in 1956, but most were collected in late May and June and most collected later were probably from the spring as indicated liy the low percentage of the two smallest lemming size classes. The 1960 sample was collected in June. In both seasons most lemmings taken in spring are in classes 3 and 4, which are small and large adult animals. The size classes of prey taken in the latter part of the season were obtained from chick pellets from enclosed nests. In 1956 chick pellets were collected from 21 July to 9 August and in 1960 from 12 July to 17 August. Large adult lemmings were predominant in both years (Fig. 3). The most significant difference between the two seasons is the occurrence of size classes 1 and 2. The mean weight of the smallest size class is 8.4 g (Table 4). 144 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 1956 80^ July 21 N= 107 60- % 40- 20- 60-1 40- % Aug. 9 N=29 llJI I960 80- 60- % 40- 20- July 12 N = I84 60-1 40- °/ /o July 30 N=46l 20 11 1:- 12 3 4 July 25 N = 163 July 29 1 N=I59 Tivrr' Aug. I7 N = 255 L I 2 3 4 Size Classes Aug. 2 N = 74 Lig. 4. Size classes of lemming femurs in penned jaeger chick pellets analyzed by slior lime intervals. William J. POMARINE JAEGER PREDATION ON BROWN LEMMING 145 According to Thompson (1955«) young Lemmus leave the nest when about 12 g in weight, and are weaned at approximately 15 g. Size class 1 is probably newly weaned lemmings or nestlings. The average weight of size class 2 is about 25 g. In 1956 size class 1 was heavily represented (35 per cent of the total) and size class 2 very slightly represented (3 per cent) ; whereas in 1960 size class 1 was 20 per cent, and size class 2 was 19 per cent of total lemming prey. The chick pellets were further analyzed by time intervals to compare seasonal trends in the age classes of prey taken (Fig. 4). In both seasons adult lemmings were most of the prey in early July. Nestling or newly weaned lemmings, (size class 1) appeared in the jaeger chick pellets in the latter part of July and subsequently increased in importance. In 1956 however, size class 1 formed a far greater percentage of the total than in 1960, 58 per cent on 29 July 1956 vs 31 per cent on 30 July 1960. The difference suggests a comparatively heavy impact on this size class in 1956. Size class 2 appeared in the 1956 sample on 29 July and reached 17 per cent of the total prey by 9 August. In 1960 the same size class appeared in the 25 July sample and steadily increased to 36 per cent of the 4 August sample and 43 per cent of the 17 August sample. The difference in the prey population in chick pellets in these two years is probably the result of difference in intensity of predation by Pomarine Jaegers in the two seasons. Figures have already been given (Table 3) on the very low reproductive success in 1956 and the very high success in 1960. It is assumed that food shortage and increased hunting intensity in 1956 resulted in a proportionately heavy take of small lemmings as soon as they were available and that the number taken was sufficient to reduce recruitment from size class 1 into size class 2 in that year. In 1960, on the other hand, food was abundant, and there was an ample number of adult lemmings available so that predation on the smaller size classes did not significantly impede recruitment into size class 2. (2) The number of prey taken. — The amount of food eaten by captive chicks is used to estimate food consumption by wild chicks. The use of captive chick food data for this purpose can be justified by comparing the growth rates of the captives with the mean growth rate of penned wild chicks. Growth of Pomarine Jaeger chicks in the first ten days is almost constant. The mean instantaneous relative growth rate of two captive chicks in that period was 16.8 and 15.6 per cent. However, both captive chicks lost weight on their first day and had negative instantaneous relative growth rates from day one to day two. Since eight penned wild chicks had a positive mean instantaneous relative growth rate of 17.5 per cent from day one to day two, I assumed that the weight loss was due to inadequate feeding. If the first days weight loss is ignored the captive chicks had mean instantaneous relative growth rates for the first ten days of 19.5 and 18.0 per cent respec- tively, approximately the same as the 19.3 per cent for the penned wild chicks in the same age period in 1960 (Fig. 5). Both the weight curve of the successful chick Hotspur and the mean curve of the penned wild chicks leveled off at about 600 g. The captive chicks were fed mostly on lemming carcasses and a few white mice, thus giving the total number of lemmings as well as the total weight of food eaten (Table 5). Most of the lemmings were entire although some were gutted. Only one chick (Hotspur, Table 5) was raised from hatching to fledging age. In 47 days this chick ate 9,490 g of Lemmus or 202 lemming carcasses. The other chick raised from hatching (MacDuff) died suddenly when 26 days old. There was no apparent cause of death, the chick began losing weight about 1 August and died three days later. In 26 days it consumed 3,521 g of Lemmus and ate 54 lemmings. 146 THE WILSON BULLETIN 800 9 9 ADULT MEAN ^ . ■ " ■ _ 6 6 • 600 . ■■ ■ • ■ ■ i" • ■ 400 - ■ ■ X X m * X ■ ■ X * ■ 40 X 1 1 1 1 1 1 1 — 1 1 1 1 1' 1 1 1 1 1 1 1 1 '1 — I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 < 1 1 ' 1 ' DAYS Fig. 5. Weight curves of two laboratory raised jaeger chicks (left) and the mean weight curve of penned jaeger chicks (right) . Two chicks near fledging weight kept for 24 and 28 days consumed an average of about 200 g or 5.5 lemmings per day. Th ese data suggest that a chick will eat about 9,500 g of food, or approximately 200 lemmings to grow from hatching to fledging. After reaching nearly full size a jaeger chick will eat 200 to 220 g of food per day, or 5.5 lemmings per day. Amount of Food Consumed Table 5 BY Captive Pomarine Jaeger Chicks in 1960 Chick Dates Age ( days ) No. of days s food g food/ day No. of Lem mils eaten Mean no./ day Hotspur 11 July-3 August 1-24 23 3,671 160 54 2.3 4^27 August 25-48 24 5,819 242 136 5.7 Total 1-48 47 9,490 202 190 4.0 MacDuff 10 July-4 August 1-26 25 3,521 141 54 2.2 Cathy 4-27 August ? ? 24 5,105 213 136 5.7 Archy 31 July-27 August ? ? 28 5,550 198 151 5.4 Miller"’ ^ POMARINE JAEGER PREDATION ON BROWN LEMMING 147 Number of Table 6 Lemmings taken by Pomarine Jaeger Pairs in 24 hours Date Year Male Female Total 7-8 July 1956 3 1-2 4-5 18-19 June 1960 3 8-9“ 11 7-8 July 1960 3.5'^ 1.5-^ 5 23-24 July 1960 2 2 4-5'* 13-14 August 1960 4“ 3 7 “ One lemming was torn apart but apirarently only partly eaten. Male caught and gutted two and was seen feeding on another lemming carcass. These were each counted as 0.5 lemming. Female caught and ate part of one, was seen picking at carcasses twice. These were also each counted as 0.5 lemming. The chicks were fed twice when the adults were not observed catching a lemming. ' The male also caught one Red Phalarope, his total for the day was four lemmings and one phalarope. One piece of information on the quantity of lemmings fed by a pair of adults to chicks was accidentally obtained in 1956. The female of a pair whose nest was fenced was dead near the nest on 22 July. The male was present, and the two chicks were still alive. There was no food in the nest enclosure. The following morning eight adult lemming carcasses were in the enclosure; that afternoon there were seven lemmings and one Steller’s Eider chick (Polysticta stelleri) . Normally, when one adult catches a lemming both fly to the enclosure and they cooperate in tugging the carcass apart so that both chicks and adults share the prey. In the absence of the female, this male was apparently unable to feed the chicks and the prey simply accumulated in the enclosure. The eight lemmings and one eider chick are a suggestion of the number of prey normally fed to two chicks if we assume that the male had eaten enough for himself. Lemmings in this part of the summer aver- aged about 50 g (Pitelka, MS). The food brought to the enclosure totaled about 450 g, allowing 50 g for the eider chick, and approximately equals the food consumed by the captive chicks. The best information on lemming consumption by adult jaegers was obtained by ob- serving breeding pairs for 24-hour periods in 1956 and 1960 (Table 6). The 24-hour watch made on 18-19 June and the two on 7-8 July, were in the incubation period and indicate approximately seven lemmings consumed by a pair of adults. The average weight of 107 lemming specimens from June and early July in 1956 was about 72 g (Pitelka, MS). The weight of seven lemmings eaten by one pair of adult jaegers in 24 hours was then about 500 g, or 250 g each. This seems very reasonable when compared with 200 to 220 g eaten by full sized chicks in captivity. Two 24-hour watches made when chicks were being fed (23-24 July, and 13-14 August) indicated an average of approximately six lemmings consumed per pair. According to what we know of consumption rates of captive chicks this is much too low. It is possible that the presence of observers inhibited the adults from normal hunting activity or from visiting the chicks. Therefore the food consumption rate of 500 g per day per pair, deter- mined for the first half of the season, was presumed to he constant for the entire season, and was also used as the adult consumption rate for the second half of the season. The number of lemmings eaten by a successful Pomarine Jaeger family was calculated from these data on food consumption. Two chicks consume the equivalent of 20.000 g of 148 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Sex Ratio of Table Lemming Pelves 7 FROM POMARINE PeLLETS Date Males Females Per cent males Per cent females Totals 1956. chick pellets 21 July 20 15 57 43 35 25 19 23 45 55 42 29 14 20 41 59 34 14 August 12 20 38 62 32 Total 65 78 46 54 143 adult pellets 104 118 47 53 222 Total 169 196 46 54 365 1960. chick pellets 12 July 39 34 53 47 73 16 59 48 55 45 107 20 86 60 59 41 146 25 62 49 56 44 111 30 71 64 53 47 135 4 August 58 38 60 40 96 8 15 20 43 57 35 17 12 20 38 62 32 Total 402 333 55 45 735 adult pellets 33 33 50 50 66 Total 435 366 54 46 801 lemmings from hatching to 31 August. Using size class distrilDution of femurs in pellets as indicating the size classes of lemmings taken in that period (Fig. 3, Table 4), it was calculated that two jaeger chicks would have eaten 339 lemmings in 1956 and 319 in 1960. The lemming consumption hy adult jaegers was calculated lor two time intervals. One interval from 25 May to 15 July is the period before the eggs hatch and before the young Lemmus of the summer generation emerge from the nest. (For the purpose of this analysis, these two events which were actually separated hy a short interval, are assumed to occur simultaneously). The second interval from 16 July through 31 August, is the time from hatching to departure from the breeding grounds. A consumption rate of seven lemmings per day per pair, derived from the results of these 24-hour watches, was used for the first half of the season, giving a total of approxi- mately 364 lemmings taken. This is the equivalent of 500 g of lemmings per day. At this same rate of consumption for the second half of the season, taking into account the shift of the age structure of the lemming population (Fig. 3), a total of 413 lemmings were eaten in 1956 and 366 in 1960. Thus a pair of adults and two chicks eats approximately 1,050 to 1,100 lemmings in one season. (3) Sex ratio of lemmings taken. — In assessing the impact of a predator on a prey pop- ulation the sex ratio of the individuals removed is as important as the numbers and age classes. Mailer ^ POMARINE JAEGER PREDATION ON BROWN LEMMING ] 49 The sex ratio of all prey pelves in both 1956 and 1960 was almost 1:1 (Table 7). Fe- males predominated slightly in 1956 (54 per cent) and males were 54 per cent in 1960. The initial sex ratio in 1956 in the jaeger chick pellett samples favored males, and there was a continuous decline of the proportion of males through the season. Only in the first sample (21 July) did the percentage of males exceed that of the females. In 1960 the sex ratio in the June sample was 1:1. In July and early August samples it was predominantly male, and only in the 8 and 17 August samples did the percentage of females exceed that of the males. Considering the small size of the samples in 1956 we cannot he certain that the shift in the sex ratio is actually as steady as the data indicate, hut a trend to a pre- dominance of female prey is indicated in contrast to the results from 1960. It is known that male lemmings, like other male microtines, range more widely than the females (Thompson, 1955a) and, hence, are presumably more exposed to predation than females are. This fact has been used to explain the predominance of males usually found in raptor pellets. The sex ratio of lemmings in Snowy Owl pellets from Barrow, for example, was 65 males to 35 females (Thompson, 1955a). The Pomarine Jaegers, how- ever, may he obtaining a more random sample of the prey population than raptorial birds such as the Snowy Owl because they appear to use auditory cues in addition to visual cues to locate prey, because they dig their prey out of the ground, and because of their comparatively small territory. Early in the season when lemmings are abundant and have little cover, jaegers hunt by flying over the tundra between 15 and 25 feet from the surface; and when a lemming is sighted the jaeger lands and grabs it with its hill. The feet are never used. After the ground thaws and after the shallow lemming burrows are open lemmings are less avail- able, and jaegers obtain them primarily by digging them out of the peat soil with their bills. They appear to use both momentary sighting of a lemming and auditory cues to locate areas in which to dig. Two characteristics of northern Alaska coastal tundra make the second hunting method feasible. The surface layer of soil which thaws in the summer, the active layer, is very shallow. In marsh areas, which are the preferred habitat of Lem- mus, it may be only six inches deep by late summer. Lemming burrows are therefore usually very shallow, in marsh peat they are typically just below the surface. Secondly, the vegetation is rarely more than five to six inches tall at the end of the growing season, and provides relatively poor cover for lemmings. One other reason why the Pomarine Jaeger should obtain a more random sample of its prey population than the Snowy Owl and other raptors relates to the relative intensity of territory use. At high densities the Pomarine Jaeger has a relatively small territory, ap- proximately 34 acres on the average, and particularly early in the season, it is confined to that area for all of its food gathering. The jaegers hunting effort for an entire season must be intensive, and its prey should ultimately reflect the actual sex ratio of the prey population. The Snowy Owl, on the other hand, occupies a much larger area, one scpiare mile or more, and does not have to harvest prey as intensively as the jaeger does. The owl appar- ently relies on visual cues to locate prey and will in the long run probably take more of those lemmings, the males, which are more active on the surface. The difference in the sex ratio of the jaeger’s total prey between 1956 and 1960 is probably explained by different intensity of predation in the two years, as a result of the difference in the number of lemmings present. In 1960 lemmings were plentiful through the season. With a readily available food supply one would expect the jaegers to take a predominance of the more active lemming sex, the male. In 1956 a shortage of lemmings 150 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 developed, and hunting was intensified as indicated by a large amount of time that jaegers spent in hunting activities such as walking and digging. Under this hunting pressure the prey taken should tend to reflect the ratio in the population or perhaps even become selective for females. Increased predation of females under these circumstances should result because in the reproductive period the females have nests of young, either on the surface of the ground or in chambers excavated just beneath the surface. A tendency to defend a nest or to remain with the young should increase the chance that a randomly encountered female would be taken by a jaeger over the chance that a similarly encoun- tered male would be taken. (4) Timing of predation. — The lemming population is free of avian predators for the first one and three-quarter to two and three-quarter years after a decline. Avian preda- tors may breed in low to moderate numbers in the third summer following a decline. Little is known of the least weasel in this period; it is rare and never seen or captured except in peak lemming years. Presumably it is an important factor only in the last year of the cycle. In a lemming-high summer, jaegers are significant as predators on the lemmings for a little more than three months, from late May until the end of August. Snowy Owls arrive earlier, in late April, and are important predators until the end of August, for four and possibly more months. They have been known to winter in areas of bigh rodent popula- tion and so could have a more prolonged effect than any other avian predator. The Short- eared Owl is sporadic in its occurrence in northern Alaska and has not nested in num- bers at Barrow since 1953. The Glaucous Gull occurs in moderate numbers along the north Alaskan coast all summer. In lemming years it is seen taking lemmings during spring melt-off. In that brief period the species probably has a significant effect on the lemming population near the coast. The Parasitic Jaeger is relatively scarce at Barrow and is primarily a bird predator. In 1956, a high lemming year, one pair appeared to feed mostly on fish. Lemmings are most vulnerable to predation in early spring; they have destroyed their vegetative cover, the only remaining cover, the snow, melts rapidly, and their burrow systems remain frozen or full of water and are unusable. Lemmings are so easily taken in spring that some waste by the predators is evident. Thompson (1955fi') found 11 to 12 dead lemmings per acre on several mortality plots in June 1953. More than half of these bore the marks of owls, jaegers or weasels. Though most of the wasted animals are eaten eventually, some are probably lost, thus increasing the total removed by the predators. A large number of Pomarine Jaegers which eventually depart without breeding add to the impact of predation in early spring. The number of excess birds differs considerably between high years. In 1956 excess birds were estimated to be equal to 25 to 50 per cent of the final breeding population, and in 1960 they were estimated to be less than 25 per cent of the breeding population. In 1952 Pitelka (1955n) estimated that excess birds numbered five times the number of breeding birds. The impact of a pair of breeding Pomarine Jaegers on the lemming popula- tion is constant until the eggs hatch in mid- July. Lood consumption then in- creases as the chicks are fed. Consumption by the chicks, and hence by the entire family, peaks when chicks are in their third week and then declines slightly. Young Lernmus emerge from the nest in mid- to late July, adding a large number of small lemmings to the prey population when jaeger chicks are Sr POMARINE JAEGER PREDATION ON BROWN LEMMING 1 5] Table 8 Total Pkedator Impact on a High Lemming Population at Bakrow Seasons lemming consumiDtion Density (Ind./ square mile ) Daily food consump- tion ( g/ind. ) (per acre) Predator Age class ( per ind. ) 25 May to 15 July 16 July to 31 August Total Pomarine Jaeger Adult 38 250 338 10 21 31 Young 38 200 167 — — Snowy OwP Adult 2 250 350 1.3 1.6 3 Young 7 150 160 — — Least weaseP 64 50 100 5 5 10 Glaucous Gulp 20 250 125 0.7 — 1 Waste 4 4 Totals 21 28 49 ^ Data from Watson, 1958. Data from Thompson, 1955fl. Estimated. hatching or partly grown; hence, the number of lemmings consumed increases at a proportionately greater rate than the weight of food consumption would indicate. Predator impact on a lemming high. — I have used the information on food habits to assess the effect of a high Pomarine Jaeger population on lemming numbers in a year such as 1956 or 1960 at Barrow. I have also tried to define the total predation impact by estimating the effect of the other lemming preda- tors (Table 8). Data for food consumption of the Snowy Owl are from Watson (1958). The density of the least weasel is that given by Thompson (1955a ') for the 1953 season; it is a conservative estimate. Data on Glaucous Gull den- sity are from my own observations; the food consumption of the gull was esti- mated on the basis of its weight. The estimate of lemmings wasted was from Thompson ( 1955a ) for the 1953 lemming high, allowing for the lower lem- ming population in 1956 and apparent lack of waste in 1960. The figures in the three right columns of Table 8 are estimates of predation on a single acre of tundra by each of these predators. The number of lem- mings consumed are for two halves of the season, for reasons already dis- cussed, with the season’s total in the right column. All predation figures are based on numbers per area without adjustment for unoccupied habitat, and thus are the lowest mean densities for the species involved. The Pomarine Jaeger takes 31 (63 per cent) of the 50 lemmings removed 152 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 9 Hypothetical Effects of Predation on High Lemming Populations of Different Spring Densities Lemming density based on individuals per acre Spring density/acre 20-30 30-40 40 50 Number of females 12.5 17.5 22.5 Females lost before breeding 10.5 10.5 10.5 Females left to breed 2 7 12 Average embiyos 6“ 6 6 Young produced 12 42 72 Total adults remaining 4 14 24 Total mid-summer population 16 56 96 Predation loss after breeding 28 28 28 Excess after predation -12 28 68 Datum from Thompson, 1955fl. per acre by all predators. Its great importance as a lemming predator is thus clearly demonstrated. I have used three broad estimates of spring lemming numbers per acre : 20- 30, 30-40, and 40-50 to assess the effect of predation on the summer lemming population, using the impact of minimum predator density in Table 8. The results (Table 9) are a mean minimum figure for the impact of predation, and suggest that total predator load can depress a spring lemming population of approximately 25 per acre but cannot depress a spring lemming population of 35 per acre or above. The results also indicate the decisive effect that preda- tion in the first half of the summer has on subsequent lemming numbers. Early removal of a relatively few females from the population can mean the differ- ence between a reduction of the lemming population in the summer or not, thus emphasizing the importance of a predator like the Pomarine Jaeger which apparently takes a greater proportion of females than do other avian predators. These calculations indicate that the predation load on the lemming popula- tion is significantly large and can depress lemming populations of some densi- ties, thus confirming the observation that the lemming population was indeed depressed markedly in one high year (1956) and not in another (1960) (Pitelka, MS). The possible effect of predation by the excess jaegers always associated with breeding populations in spring has not been included in the estimate of total predation load. I have no precise data on their numbers, hut their impact can he estimated if we assume there are as many as 25 to 50 per cent of the maxi- ZTeT ^ POMARINE JAEGER PREDATION ON BROWN LEMMING 153 mum breeding population and that they are present in the population for ten days. Under these circumstances they would add 0.5 to 1.0 lemmings per acre to the early season predation impact, and reduce the fall lemming population by two to three lemmings per acre. Assuming they were present as long as 20 days would reduce the fall lemming population by three to six lemmings. These figures do not suggest that this extra spring predation is significant in the total predation load; but it could be pivotal in some years. Lemming mortality from causes other than predation has been ignored in this discussion. Thus, lemming nestling mortality from action of intraspecific factors, spring flooding, and exposure probably account for some additional mortality; and disease and parasitism while not significant (Krebs, 1964) also remove a few. This argument has been based on a hypothetical population of jaegers with 100 per cent reproductive success. In fact, success is never that high. Yet, the most decisive part of the season as far as impact on the lemming population is concerned is the first half; and in 1956, a very unsuccessful season for the jaegers, most of the pairs which began to breed were still present in mid- July. The decline of the jaeger population did not take place until the late July when food shortage and consequent chick starvation began to occur. Hence, even in a year when the breeding effort of the predators fails, they may have a critical effect on the prey population by their impact before its summer breeding. DISCUSSION The role of predation in the lemming eycle. — Most modern students of the lemming cycle reject the idea that the cycle is caused by predators (Krebs, 1964). Predators do kill a large number of lemmings, and Pitelka, Tomich, and Treichel (1955a) suggested that under some circumstances predators could affect the periodicity of the cycle by postponing a population peak from one season to the next. They suggested that in a summer of moderate lemming numbers, in 1952 at Barrow, the predators prevented the lemmings from in- creasing and postponed the lemming population peak to the summer of 1953. Current hypotheses are concerned with causative factors intrinsic to the lem- ming population (Christian, 1950; Chitty, 1952) or are concerned with inter- action of the lemming population with its food supply (Lack, 1954; Pitelka, 1957). However, Pearson (1966) studied the effectiveness of mammalian predators on a complete cycle of abundance of Mierotus ealijornicus and con- cluded that carnivore predation was “an essential part of the regular cycles of abundance of lemmings, Mierotus, and other microtines.” According to Pearson mammalian predators are not necessarily important in starting the decline from the population peak, hut are important in reducing 154 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 the population to the lowest part of the cycle and in maintaining the low pop- ulation until they themselves starve. Their action accounts for one of the most inexplicable aspects of the lemming cycle; the long delay in recovery from the population low. Since avian predators are not present in significant numbers during the lem- ming population build up, their role in the cycle in northern Alaska is prac- tically restricted to their action on the lemming peaks. The evidence presented here shows that avian predators do take a large number of lemmings and that at some lemming densities they can markedly depress the lemming population, while in others they cannot. There is also observational evidence that lem- mings may be reduced in numbers by avian predators (1956 ), or they may increase despite the action of avian predators as in 1960. The events of 1956 demonstrated dramatically that the avian predators cannot be responsible for a complete lemming decline as in that year most of the jaeger chicks starved when it was still possible to snap trap some lemmings. The role of the avian predators in the lemming population cycle in northern Alaska then seems to he the exploitation of the peak population and to truncate the top of the peak by their action. The role of mammalian predators in the lemming cycle in northern Alaska has not been studied; but the large population of least weasels which occur in the peak summer must persist into winter, and since there is no alternative prey, they must continue to prey on the lemmings remaining after the avian predators depart. Arctic foxes are also usually abundant at the end of lem- ming-peak sum.mers. They are not usually seen near Barrow in the summer, but in autumn numbers of young of the year are seen apparently foraging for lemmings. Thompson (19555 ) interpreted the results of his study of the lem- ming population from 1950 to 1954 at Barrow as being best explained by Lacks’ (1954) food hypothesis. Yet he also says (Thompson, 19556, p. 173) that “our field evidence strongly suggests that it is the continued pressure by weasels through the winter which eventually reduced the lemmings to the ex- tremely low numbers of 1950 to 1954. As lemmings declined in abundance, the owls, jaegers, and foxes emigrated and shifted to other food, but the weasels’ only alternative was to extend their efforts in pursuing the remain- ing lemmings.” Maher (1967 ) presented evidence that a low to moderate win- ter population of lemmings was almost destroyed by predation by ermine on Banks Island, N.W.T. These observations strongly suggest that predation, par- ticularly by weasels, may in fact be responsible for the great decline of lem- mings in the winter after a peak summer in northern Alaska, and thus may be causing the population cycle. Evidence from the eastern North American arctic is not as suggestive, but Sr"' ^ POMARINE JAEGER PREDATION ON BROWN LEMMING 135 both Krebs (1964) and MacPherson (1966 ) working in areas where the two lemming species [Lemmus and Dicrostonyx) occur together in a mosaic of habitats which bring them in close proximity found that their populations cy- cled synchronously. Synchrony of the two species suggests some external ac- tion tending to keep them in phase, and predation by mammalian predators is a very possible responsible factor, although Krebs (1964) rejected this pos- sibility. The possibility that the action of mammalian predators in reducing the pop- ulation and prolonging the low is responsible for the cycling of the lemming population now seems tenable and should be studied further. SUMMARY Food halaits, breeding density, and breeding success of Pomarine Jaeger populations nesting in response to different spring densities of the brown lemming population were studied at Barrow, Wainwright, Pitt Point, and Cape Sabine, northern Alaska. Food habits of nonbreeding populations were studied for comparison with breeding populations. When Pomarine Jaegers breed, their food supply is at least 80 per cent lemmings with birds the next most important food category. Lemmings occurred in less than half of the stomachs of nonbreeding populations, suggesting that the jaeger cannot obtain enough food to support breeding unless there are enough lemmings to provide most of its food. Jaeger breeding density correlated with spring density of the brown lemming up to a maximum density of approximately 19 pairs per mile. Three lemming highs (1953, 1956, and 1960) supported virtually identical mean Pomarine Jaeger densities although lem- ming density differed between peak years. Breeding success was low at low breeding densities and low to moderate at intermediate densities. At maximum density, breeding success ranged from almost complete failure (1956) to high success (1960). The size classes of lemmings in the jaegers’ diet was determined from the length of fe- murs in regurgitated food pellets of adults and chicks. The number of prey taken was determined by the amount of food eaten by chicks raised in the laboratory, and by several 24-hour watches of jaeger pairs. The sex ratio of lemming prey was determined from the pelves in jaeger pellets. Calculations from these data indicate that a pair of jaegers raising two chicks in a year of maximum jaeger density remove an average of 31 lemmings per acre from their territoi'y in the season. Other predators remove an additional 18 for a total of 49 lemmings removed per acre by the action of all predators. This is sufficient to depress a lemming population of approximately 25 per aere in the spring but not a population of 35 per acre or above. The role of the avian predators in the lemming cycle is to truncate the peak populations, but they are unable to reduce the lemming population to the low point of the cycle. It is suggested that mammalian predators, especially Mustella rixosa, are responsible for reduc- ing the population completely and delaying recovery of the lemming population until they themselves decline in numbers. ACKNOWLEDGMENTS Financial support for the field portion of this project was provided by the Arctic Insti- tute of North America under contract with the Office of Naval Research. Logistic support 156 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 was from the Arctic Research Laboratory at Barrow, Alaska. The assistance of these agencies is gratefully acknowledged. I am grateful to Frank A. Pitelka for advice in the course of this study. I also wish to thank Ira L. Wiggins, Director of the Arctic Research Laboratory in 1956, and Max C. Brewer, his successor, for their generous support of my field activities. Many investigators and staff members at the Arctic Research Laboratory have gener- ously provided information and time to this project. I regret that I cannot express appre- ciation for all of those contributions. I particularly thank: J. Dow, R. T. Holmes, M. P. Marsh, F. A. Pitelka, J. Reynolds, and T. Sovalik. Dow helped map the Pomarine Jaeger nests in 1956, Holmes and Reynolds helped in 1960. Holmes, Marsh, Reynolds, and Sovalik assisted in several 24-hour watches of Poma- rine Jaegers in 1956 and 1960. Grateful acknowledgment is made of facilities and support provided by the Museum of Vertebrate Zoology and the Department of Zoology of the University of California, Berkeley. LITERATURE CITED Bent, A. C. 1921. Life histories of North American gulls and terns. U. S. Natl. Mus. Bull., 113. Black, R. F., and W. L. Barksdale. 1949. Oriented lakes of northern Alaska. J. Geoh, 57:105-118. Britton, M. E. 1957. Vegetation of the Arctic tundra. Eighteenth Ann. Biol. Coll., Ore- gon State College, pp. 26-61. Childs, H. E., Jr. 1959. Vertebrate ecology of coastal tundra in northwestern Alaska. Unpubl. Ph.D. thesis. University of California, Berkeley. Chitty, D. 1952. Mortality among voles (Microtus agrestis) at Lake Vyrnwy, Mont- gomeryshire in 1936-39. Phil. Trans. Royal Soc. London, Ser. B, Vol. 236:505-552. Christian, J. J. 1950. The adrenal-pituitary system and population cycles in mammals. J. Mammal., 31:247-259. Dunmire, W. W. 1955. Sex dimorphism in the pelvis of rodents. J. Mammal., 36:356- 361. Krebs, C. J. 1964. The lemming cycle at Baker Lake, Northwest Territories, during 1959-62. Arctic Inst. N. Amer. Tech. Paper No. 15. Lack, D. 1954. The natural regulation of animal numbers. Oxford. MacPherson, a. H. 1966. The abundance of lemmings at Aberdeen Lake, District of Keewatin, 1959-63. Canadian Field-Naturalist, 80:89 94. Maher, W. J. 1967. Predation by weasels on a winter population of lemmings. Banks Island, Northwest Territories. Canadian Field-Naturalist, 81 :248-250. Pi-ARSON, 0. P. 1966. The prey of carnivores during one cycle of mouse abundance. Anim. Ecoh, 35:217-233. Pitelka, F. A. 1957a. Some characteristics of microtine cycles in the arctic. Eighteenth Ann. Biol. Coll., Oregon State College, pp. 73-88. Pitelka, I". A. 19576. Some aspects of population structure in the short-term cycle of the brown lemming in norlhern Alaska. Cold Spring Harbor Symp. Quant. Biol., 22: 237-251. Pitelka, F. A., P. Q. Tomicii, and G. W. Treichel. 1955c. Ecological relations of jaegers and owls as lemming predators near Barrow, Alaska. Ecol. Monogr. 25-85- 117. Maher ^ POMARINE JAEGER PREDATION ON BROWN LEMMING 157 PiTELKA, F. A., P. Q. Tomicit, AND G. W. Treiciiel. 19556. Breeding Ijehavior of jaegers and owls near Barrow, Alaska. Condor, 57:3-18. Rausch, R. 1950. Observations on a cyclic decline of lemmings {Lemmus) on the arctic coast of Alaska during the spring of 1949. Arctic, 3:166-177. SiiELFoRD, V. E. 1943. The abundance of the collared lemming (Dicrostonyx groen- hindicus (Tr.) var. nchardsoni Mer.), in the Churchill area, 1929 to 1940. Ecology, 24:472-484. Spetzman, L. a. 1959. Vegetation of the arctic slope of Alaska. U. S. Geol. Surv. Prof. Paper 302-B. Thompson, D. Q. 1955fl. The ecology and population dynamics of the brown lemming (Lernmus trimiicronatus) at Point Barrow, Alaska. Unpubl. Pb.D. thesis, Univ. of Missouri. Thompson, D. Q. 19556. The role of food and cover in population fluctuations of the brown lemming at Point Barrow, Alaska. Trans. N. Amer. Wildl. Conf., 20:166-176. Thompson, D. Q. 1955c. The 1953 lemming emigration at Point Barrow, Alaska. Arctic, 8:37-45. Watson, A. 1958. The behaviour, breeding, and food-ecology of the Snowy Owl Nyctea scandiaca. Ibis, 99:419-462. DEPARTMENT OF BIOLOGY, UNIVERSITY OF SASKATCHEWAN, SASKATOON, SAS- KATCHEWAN, 16 AUGUST 1968. A POPULATION ESTIMATE OE THE DUSKY SEASIDE SPARROW Brian Sharp During the spring of 1968 I attempted to determine the absolute numbers and distribution of the Dusky Seaside Sparrow {Ammospiza nigrescens), which has been regarded as threatened with extinction ( Bureau of Sport Fish- eries and Wildlife, 1966). Most of the few completed world population cen- suses of birds fall into four general types: those concerning (1) large and conspicuous species, often water birds, and often lending themselves to aerial census and photographic techniques, such as the North Pacific albatrosses (Rice and Kenyon, 1962) ; (2) populations that gather into few traditional breeding or wintering concentrations, such as the Gannet (Fisher and Vevers, 1944) ; (3) conspicuous endangered species, of at least seasonally restricted distribution, such as the California Condor (Miller, McMillan and McMillan, 1965) ; and (4) less conspicuous species of a very restricted distribution, often on islands, like the Takahe (Williams, 1952). The Dusky Seaside Sparrow, confined to the salt marshes of Brevard County, Florida, falls into this last category. For a review of the early literature on total-bird-population censuses, see Fisher (1954). HISTORY Ammospiza nigrescens was discovered in 1872 around Salt Lake on the Florida mainland (Fig. 1) (Maynard, 1875), where it was presumably always rare (Chapman, 1899). Certainly it has not been seen there since ( Baynard, 1914; Charles H. Trost, in litt.). Maynard found the species abundant on the salt marshes of the northern half of Merritt Island, and Chapman (1899, 1912) reported it there from Banana Creek to the mouth of Dummitt Creek ( see also Baynard, 1914; Vars, 1926). Charles E. Carter, a friend of the late D. J. Nicholson, told me that it was not uncommon for the latter to find 30 Dusky nests in a day s egg-collecting in just that part of the salt marsh across the bridge from Titusville. In addition, Nicholson ( 1929) reported a colony of 20 pairs on the mainland, IV2 miles east of the St. John’s River, due west of In- dian River City. Since 1957, the Merritt Island salt marsh has been impounded for mosquito control (for vegetation changes, see Provost, 1959; Trost, 1968 ) with the result that by 1961-63 the Dusky Seaside Sparrow population had been leduced to (a minimum of) four aggregations totaling approximately 70 pairs (Trost, in litt.). Trost also found that the colony on the mainland had dwindled by 1962 to about five pairs, and subsequently these birds disappeared entirely (Bureau of Sport Fisheries and Wildlife, 1966:B-49) . A. nigrescens is 158 Brian Sharj) DUSKY SEASIDE SPARROW POPULATION 159 Fig. 1. Pre.sent and former distribution of the Dusky Seaside Sparrow, Brevard County, Florida. at the moment on the rare and endangered species list of the U. S. Eish and Wildlife Service (ibid.) . It was because of this critical situation that the pres- ent study was undertaken. METHOD The census method was the singing-male count, which is most efficient for inconspicuous small birds in dense cover, where flushing distances are short and the habitat extensive. However, the method has two major disadvantages: it is less than 100 per cent efficient, and variably so. When one visits a given nesting area, only a certain proportion of the total males present will he singing, depending upon the stage of the breeding cycle, time of day, climate, and weather. This proportion, designated ejject.ivity by European ornithol- ogists (Enemar, 1959; Williamson, 1964) is a refinement of Colquhoun’s (1940) “co- efficient of conspicuousness” (see also Palmgren, 1930; Hickey, 1943:83; Nice, 1943:122- 160 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 4). Effectivity is determined by repeatedly visiting, at different times of the day, a num- ber of colonies (whose total male population becomes known in the process) and by map- ping the males recorded. The percentage of males recorded singing on any one visit is the effectivity, or efficiency of the census (hereafter designated Ef ). To increase sam- ple size Ef data were on a few occasions gathered from study areas censused only twice, and the population was taken to be the numher seen on the highest count, the lower count being compared to this for the purpose of effectivity. If the summation method of Palm- gren (1930:93) is used in conjunction with the mapping method, the higher of the census figures can also be used for Ef, this being compared to the non-overlapping composite of the two or more counts. Ef tends to he overestimated if the area has not been censused at least three or four times and the locations of singing males mapped. Most of the area was covered on foot, part on horseback, and part by bicycle. A heli- copter was used to determine the simple presence or absence of tbe Dusky Seaside Spar- row in some of those areas not covered from the ground due to lack of time. If one flies at 100 ft at 30 mph over the marshes, all species of birds flushed, including passerines, can be identified from prior field experience on the ground. The Dusky Seaside Sparrow is distinctive, especially in flight, and could be carelessly confused only with the female Red-winged Blackbird (Agelaius phoeniceus) . THE AREA For a description of typical salt marsh habitat on Merritt Island, see Nicholson (1928: 229) and Trost (1968:851). The Dusky Seaside Sparrow uses the restricted zone where the short grass Distichlis spicata and the tall Spartina bakeri interdigitate, producing a heterogeneous pattern. For a botanical treatment of the St. John’s marshes, including a point-cfuadrat analysis, see Sincock (1958). The marshes on the mainland between Routes 520 and 46 are dominated by salt-marsh plants, primarily Spartina bakeri, and dotted with palm trees iSabal palmetto) and hammocks, so that the total aspect is savannah-like. Wa- ter levels and salinities vary considerably with the precipitation pattern, with a correspond- ing variability in the height and density of the Spartina, thus providing diversity of bird niches within the same tail-grass life form. Because salinities are low at times of high water, a number of freshwater marsh plants add variety to the vegetation but are never dominant. The mainland salt marsh owes its existence to Pleistocene interglacial invasion by marine waters below the 20-ft contour line, when salt was deposited in the sediments (Odum, 1953). Usually much of the St. John’s is inaccessible, but 1968, the second year of a general Florida drought, was opportune for the purposes of census. RESULTS AND DISCUSSION Ligure 2 shows the bimodal effectivity curve as a function of the time of clay, the peaks occurring in the early morning and evening. The discrepant Ef ( 86 per cent ) for the hour of 12:00-12:59, based on one observation period during and after a light rain, was due to the vigorous resumption of singing characteristic of the species under such conditions (Trost, 1968:852). The maximum average Ef figure of 73 per cent for the early morning agrees sur- prisingly well with Enemar’s effectivities for the Willow Warbler {Phyllosco- pus trochilus) (73 per cent). Garden Warbler {Sylvia borin) (73 per cent). OvUAan Bunting {Ernheriza hortidan a) (65 per cent ), etc. (Enemar, 1959:32), 161 DUSKY SEASIDE SPARROW POPULATION Fig. 2. Efficiency of the census (effectivity) expressed as a function of the time of clay. Vertical lines through the means are confidence limits (95 per cent), n is sample size for the line of 22 April-30 June. Curve is drawn in visually. but is less than the 88 per cent for the American Woodcock {Philohela minor) I Duke, 1966; Sharp, unpubl. ), whose activities are concentrated into a short crepuscular period. In contrast to the present study, Enemar (1959:27) found that effectivities were almost constant throughout the day, this perhaps being a reflection of the more uniform Swedish woodland climate. This and the fact that a shower can stimulate singing in the middle of the day imply that the pattern of singing activity is not part of a circadian rhythm, but is a function of microclimatic conditions, specifically, in an exposed salt marsh, either of the oppressiveness of the heat or of light intensity. Ricklefs and Hainsworth (1968) report on the temperature-dependent behavior of the Cactus Wren {Campylorhjnchus brunneicapiUus ) , which selects cooler microhahitats in- creasingly toward early afternoon, unless cloud cover allows the birds to fre- quent more exposed areas. One of the reasons that the effectivities for nigres- cens are as high as they are in the middle of the day (27 per cent) is the effect of either the bird detecting the observer or being flushed by the observer walk- ing through the grass, after which males had a tendency to sing briefly, stimu- lating their neighbors to do the same. Spontaneous sporadic outbursts of ter- ritorial behavior also occur (Nicholson, 1928:228), interrupting the general midday silence and raising the average Ef. 162 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 Due to an atypical coolness of the spring, effectivities were lower, although not significantly so, during the first four weeks of the singing period than dur- ing the second and third four-week periods, between which there was no dif- ference. By summer, singing intensity is reported to diminish markedly ( cf. Davis, 196.5). There was no difference between the effectivities of the Merritt Island and the St. John’s birds, even though densities were significantly dif- ferent ( 6.7 ± 0.6 and, in the best areas, 3.0 ± 0.3 acres/bird, respectively, P = 0.05). THE CENSUS Merritt Island National Wildlife Refuge. — On Merritt Island, traditional haunt of nigrescens and mecca for birdfinders (Pettingill, 1951:85), six weeks of repeated searching and territorial mapping revealed a remnant population of 33—34 males, all but 4 or 5 of which were located in breeding aggregations of 7, 8, and 14 birds. This represents a decrease of at least 50 per cent over the past 5 years. In 1968 these 29 males occupied 200 acres of remaining suit- able salt-marsh vegetation at the above-mentioned comparatively low density. Another two males, apparently unmated, were attempting to subsist on small territories of 1.1 and 0.8 acres, and at least two wandering males did not have permanent territories at all. Of 7,565 acres of impounded salt marsh only about 6,000 were originally suitable habitat for the Dusky Seaside Sparrow if one assumes that the birds had to be within a certain distance (2,300 ft ) of the tidal zone either for feeding (Tomkins, 1941; Trost, 1968:852) or for reasons of habitat selection (the grass Distichlis occupies a lower place in the salt- marsh plant zonation: Chapman, 1960:256-9) . If one assumes also that their former density was similar to that now found on the St. John’s River (perhaps an underestimate, cf. Trost, 1968:852) and that all suitable habitat was filled, an estimate of the former population on Merritt Island is of the order of 2,000 pairs. This seems not unreasonable in view of the above testimony to the for- mer abundance of the bird. St. Johns River. — In May and June, 372 singing males, many of which were paired, were found on the St. John’s River marshes in breeding; asaregations of various sizes, 95 in the largest. In Table 1 the number of birds found at any particular time of day is divided by the corresponding known Ef figure to arrive at a more realistic population estimate. Eor convenience, some of the not significantly differing Ef values of Eigure 1 have been lumped, and 14 birds found by revisiting colonies were excluded as these were accounted for by means of Ef. Thus 358 males found actually represent about 641 males in the area searched. Of these 358, all but 33 were found between the 10- and 15-ft contour lines of the USGS quadrangles, and none above 17-18 ft. Above this elevation the marsh is often dry enough for invasion by Sabal palmetto Hrian Sharp DUSKY SEASIDE SPARROW POPULATION 163 Table 1 The Number of Males Found in the St. John’s River Marshes OF THE Day Corrected for Effectivity AT Various Hours Eastern Standard Time No. of males found Effectivity Corrected no. of males Mean 95 per cent Mean 95 per cent limits Lower UpiDer 06:00-08:59 217 0.71 0.63-0.78 305.6 278.2 344.4 09:00-09:59 40 0.54 0.40-0.68 74.1 58.8 100.0 10:00-10:59 29 0.42 0.28-0.57 69.0 50.9 103.5 11:00-16:59 31 0.27 0.18-0.38 114.8 81.6 172.2 9 0.86 0.60-0.98 10.5 9.2 15.0 17:00-19:59 32 0.48 0.34-0.62 66.7 51.6 94.1 358 640.7 530.3 829.2 and is susceptible to burning, while below 10 ft the flooding of the river prob- ably sets a lower limit to colonization. Ninety-five per cent of the Dusky Sea- side Sparrow nests [n = 39) are located between 10 and 13 inches above the ground, but two weeks after the near hurricane of 3-5 June which deposited 14 inches of water, there were still 2 ft of water below the 10-ft contour, whereas a number of other revisited colonies were for the most part on dry ground. The day after the hurricane, water depth in one colony was 5-7 inches. On Merritt Island, where the effect of the tides (except wind tides) is negligible, the seaside sparrow has evidently lost the habit of nesting higher. In comparison, the New Smyrna Seaside Sparrow (A. maritima pelonota), with a former colony located at the mouth of a tidal inlet, builds a nest whose average height above the ground was 19-26 inches (95 per cent limits, u = 24). (These and the above nest data were taken from the slips for the egg collections of the late Charles E. Carter, Orlando, and Clemson University. Clemson, South Carolina. ) The river is used by cattle for drinking water in the dry season; consequently, areas below 10 ft tend to be heavily grazed. Using a planimeter, large-scale (1 in. = 400 ft.) aerial photographs (flown 1967), and USGS quadrangles for reference to contour lines, I measured the areas searched, left unsearched, less than 10 ft, 10-15 ft, and above 15 ft (Ta- ble 2 ) . The 641 males occupied an area of 2,980 acres, with an overall density of 4.65 acres/male. Of the unsearched habitat which appeared suitable from the aerial photographs, most of which lay between 10 and 15 ft, and in one area of which a Dusky Seaside Sparrow was flushed by the helicopter, there are possibly another 629 males. This, however, represents a maximum num- ber because field investigation will prove some of this area unsuitable. Much 164 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Estimate of the Dusky Seaside Table 2 Sparrow Population in the Spring, 1968 St. John’s Marshes, Corrected no. of males No. of acres per male Habitat Acres Mean 95 per cent limits Mean 95 per cent limits Searched No. present 2983^ 641 530-829 4.65 3.60-5.63 No. absent 59412 Unsearched Good: 10-15 ft, ungrazed, unhurned 9762 210 173-271 4.65 3.60-5.63^ Poor: 10-15 ft. grazed or burned 2872 43 39-47 6.7 6.1-7.35 Unlikely: <10 ft. or >15 ft 843 — — — — Total 894 742-1147 ^ Almost all 10—15 ft above sea level. -.513 acres <10 ft, 4433 acres 10-15 ft, and 995 acres >15 ft. ^ 40.2 per cent of the actual acreage, based on the fact that 59.8 i>er cent of searched habitat between 10 and 15 ft was either unsuitable or unfilled. ■* Assumed to be the same as the density in searched habitat. ® The density of the Merritt Island popidation. of the St. John’s is grazed by Brahma cattle and burned by ranchers to provide higher-quality forage. By the second or third year after burning, the grass is high enough again to be utilized by the Dusky Seaside Sparrow, but it is im- possible to say with certainty from aerial photographs alone what conditions will be actually encountered. A second reason for habitat proving unsuitable is the fact that the Dusky occupies a middle position along a moisture gradient where the density of the Spartina is 1741 ± 24 stems/m“ and the height 3.05 ± 1.29 ft (P = 0.05). Numerous references in the literature testify that the habitat of the Dusky Seaside Sparrow is somewhat drier than most salt marshes, and on the St. John’s this preference is evident from the bird’s dis- tribution. The bird is usually absent from wetter low places where the Spartina is more dense; and in the driest areas where the Spartina is shorter and thin- ner, nigrescens is replaced by the Eastern Meadowlark {Sturnella inagna) . Eurther, the breeding distribution of nigrescens tends to be aggregated due to social tendency (cf. Tomkins, 1941 for A. m. macgillivraii) . For these reasons, I found that about 60 per cent (4,434 acres) of the Spartina marsh was either unsuitable or unfilled, which proportion probably applies to unsearched habi- tat. Therefore, the possible 629 additional males should be reduced to a prob- able 25.3 (9.5 per cent limits 213— .31d) • The total number of male nigrescens Brian Sharp DUSKY SEASIDE SPARROW POPULATION 165 on the St. John’s, actual and probable, is about 894 (95 per cent limits 742- 1147). SUMMARY A singing-male census of the endangered Dusky Seaside Sparrow, conducted in the spring of 1968, revealed a remnant population of 33-34 males on Merritt Island and a here- tofore unknown population of 372 males in the St. John’s River marshes between Routes 520 and 46 on the east side of the river. Efficiency of the census varied from 73 per cent (95 per cent confidence limits 63-82 per cent) from 06:00-08:00, dropping gradually throughout the morning to a low of 27 per cent (18-38 per cent) from 11:00 to 17:00, and rising again in the evening to 48 per cent (34^62 per cent). Therefore, the St. John’s figure of 372 actually represents about 641 males (95 per cent limits 530-829). An addi- tional 253 males probably exist in unsearched habitat. ACKNOWLEDGMENTS I would like to express my gratitude to the Mary Livingston Griggs and Mary Griggs Burke Foundation for financing this study; the U. S. Fish and Wildlife Service, especially Curtis T. Wilson, manager of Merritt Island National Wildlife Refuge, for providing the refuge field headquarters as living accommodations; Jack Salmela, Director of the Brevard County Mosquito Control District, for use of their helicopter; the county engineers’ office in Titusville for donating $100 worth of aerial photos of the St. John’s; Paul W. Sykes, Jr., endangered species biologist, for census help; Jerome Carroll, assistant refuge man- ager, for accompanying me into the St. John’s on horseback; and my wife Kathi on gen- eral principles. Nita Hewins typed the final draft of this report. I am especially indebted to J. J. Hickey for his advice, encouragement, and constructive criticism throughout the course of the research and the preparation of the manuscript. LITERATURE CITED Baynard, 0. E. 1914. The Dusky Seaside Sparrow. Oologist, 31:130-134. Bureau of Sport Fisheries and Wildlife. 1966. Rare and endangered fish and wild- life of the United States. Res. Publ. No. 34, Washington, D. C. Chapman, F. M. 1899. The distribution and relationships of Aininodramus marilimus and its allies. Auk, 16:1-12. Chapman, F. M. 1912. Handbook of birds of eastern North America (rev. ed.). D. Appleton and Co., New York. Chapman, V. J. 1960. Salt marshes and salt deserts of the world. Leonard Hill, London, and Interscience, New York. CoLQUHOUN, M. K. 1940. On visual and auditory conspicuousness in a woodland bird community: a quantitative analysis. Proc. Zook Soc. London, 110:128-148. Davis, J. 1965. The “singing male” method of censusing birds: a warning. Condor, 67: 86-87. Duke, G. E. 1966. Reliability of censuses of singing male woodcocks. J. Wildl. Mgmt., 30:697-707. Enemar, a. 1959. On the determination of the size and composition of a i)asserine bird population during the breeding season : a metbodological study. Var Fagel- varld, SuppL, 2:1-114. Fisher, J. 1954. A history of birds. Houghton Mifflin Co.. Boston. 166 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Fisher, J., and H. G. Vevers. 1944. The breeding distribution, history and population of the North Atlantic Gannet (Sula bassana) . J. Anim. Ecoh, 13:49-52. Hickey, J. J. 1943. A guide to bird watching. Oxford Univ. Press, NeV York. Maynard, C. J. 1875. A new species of Finch from Florida. Amer. Sportsman, 5:248. Miller, A. H., I. I. McMillan, and E. McMillan. 1965. The current status and wel- fare of the California Condor. Natl. Audubon Soc., Res. Rep., No. 6. Nice, M. M. 1943. Studies in the life history of the Song Sparrow. II. Trans. Linnaean Soc. New York, 6:1-328. Nicholson, D. J. 1928. Nesting habits of the Seaside Sparrows in Florida. Wilson Bull., 40:225-237. Nicholson, D. J. 1929. Breeding of the Dusky Seaside Sparrow on the mainland of Florida. Auk, 46:391. Odum, H. T. 1953. Factors controlling marine invasion into Florida fresh waters. Bull. Marine Sci. of the Gulf and Caribbean, 3:134^156. Palmgren, P. 1930. Quantitative Untersuchungen iiber die Vogelfauna in den Wiildern Siidfinnlands. Acta Zool. Fennica, 7:1-218. Pettingill, 0. S., Jr. 1951. A guide to bird finding east of the Mississippi. Oxford Univ. Press, New York. Provost, M. W. 1959. Impounding salt marshes for mosquito control . . . and its effects on bird life. Reprint from Florida Naturalist, 32. Rice, D. W., and K. W. Kenyon. 1962. Breeding distribution, bistory, and populations of North Pacific albatrosses. Auk, 79:365-386. Ricklefs, R. E., and F. R. Hainsworth. 1968. Temperature dependent behavior of the Cactus Wren. Ecology, 49:227-233. SiNCOCK, J. L. 1958. Waterfowl ecology in the St. John’s River valley as related to the proposed conservation areas and changes in the hydrology from Lake Harney to Ft. Pierce, Florida. Florida Came and Fresh Water Fish Commission, Fed. Aid Project W-19-R. Tomkins, I. R. 1941. Notes on Macgillivray’s Seaside Sparrow. Auk, 58:38-51. Trost, C. H. 1968. Dusky Seaside Sparrow. In A. C. Bent (0. L. Austin, ed.). Life Histories of North American Cardinals, Grosbeaks, Buntings, Towhees, Finches, Spar- rows, and Allies. U. S. Natl. Mus. Bull., 237:849-859. Vars, H. N. 1926. Florida notes. Oologist, 43:2-9. Williams, C. R. 1952. Notornis in March, 1951. Notornis, 4:202-208. Williamson, K. 1964. Bird census work in woodland. Bird Study, 11:1-22. DEPARTMENT OF WILDLIFE ECOLOGY, UNIVERSITY OF WISCONSIN, MADISON, WIS- CONSIN 53706, 14 OCTOBER 1968. AN INVESTIGATION OF TERRITORIAL BEHAVIOR IN THE AMERICAN REDSTART UTILIZING RECORDED SONGS Roy a. Ickes and Millicent S. Ficken The territorial behavior of the American Redstart [Setophaga ruticilla) has been studied by Hickey (1940), and in greater detail by Ficken (1962 ). Hickey has described this species as being “highly territorial,” de- fending an area by song and formalized displays. Ficken has described the territory as being maintained during the breeding season with both sexes usually remaining completely within it; the male defends the area against other male redstarts. The objective of this investigation was to examine ex- perimentally territorial aggression in male American Redstarts in relation to their breeding condition, the size of their territory, and the location of an encounter within their territory. The area and changes in size of redstart territories were also studied. These factors and their effect on territorial behavior in other birds have been examined in a number of studies. The nature of encounters in territorial male Ovenbirds iSeiurus aurocapillus) varied as the breeding cycle of the birds progressed fWeeden and Falls, 1959). The fact that a territory is de- fended with increased vigor the smaller its size and the nearer the intruders approach its center has been recorded (e.g., Bremond, 1963; Armstrong, 1965 ) . Evidence that territories are compressible but that a minimum size appears to exist has been presented by Huxley (1934) and more recent investigators have elaborated on his ideas (Tinbergen, 1957). Observations of the effect of these factors on the response of a territorial male redstart have been referred to in several studies (Ficken, 1962; Ficken and Ficken, 1965 ), but this particular aspect of redstart behavior has not previously been studied experimentally. Several field studies have shown that tape-recorded songs and calls are stimuli sufficient to evoke behavior which normally occurs in response to the singing of another bird (e.g., Weeden and Falls, 19.59; Stein, 1963). Bremond (196.3) has stated that the reaction of a territory owner to a pre- viously recorded song was immediate and definite; the bird would approach and sing near the loudspeaker. MATERIALS AND METHODS This study was conducted at the Patuxent Research Refuge, Anne Arundel and Prince Georges Counties, Maryland. The habitat consisted of areas with an understory of bushes and young trees 5-20 feet high with much herliaceous undergrowth. Such habitat has been considered typical for this species ( Griscom and Sprunt, 1957; Ficken, 1962). Male redstarts on adjacent territories were recognizable as individuals by differences in color pattern, eliminating the need for color banding. 167 168 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 In the spring of 1967 two phases in the breeding cycle of the redstart were studied. One series of experiments was conducted from 24 April to 4 May before the males had acquired a mate (pre-mating); the second series, 10 May to 21 May, was run between the time a mate was acquired and the end of nest building (post-mating). In a study of courtship in the redstart, Ficken (1963) observed that “A female never left a male after she once remained for as long as an hour.” Therefore, we considered a bird mated if a female was present in the territory of a male during the major portion of an observa- tion period (i.e., one hour). In all cases this criterion proved to he a valid indication of suhsecpient and continued matedness of the male. The redstart possesses two song types: an Accented Ending Song (A) and an Unac- cented Ending Song (Ul which apparently differ in motivation and function (Eicken and Ficken, 1965). Since an analysis of these song types by Ficken and Ficken (MS) showed that playback of the A-type song usually induced significantly closer approaches to the speaker than playback of the U-type song, an Accented Ending Song obtained from the Federation of Ontario Naturalists Warbler Record was used in all the experi- ments. The playback tape consisted of a six-minute sequence of six repeats of the song per minute. An Uher 4000 S portable tape recorder and a Nagra DH amplifier-speaker were used. The volume of the speaker was maintained at maximum level and could he heard 200 feet away by the observers; during all playbacks the redstarts were within 100 feet of the speaker. Several days before the redstarts were expected to arrive at the Refuge, a pre-determined study area of approximately 20 acres was staked out. When a male redstart was first seen in the study area during phase I (pre-mating), it was observed for at least one hour and each tree that it flew into was marked. (Each bird sang from most of the trees it visited.) The marked trees were plotted on a sketch map of the area and the locations of encounters with other male redstarts were recorded. Each of the plotted points on the sketch map of the bird’s activities was connected to all the other plotted points by a straight line. The area of the polygon thus formed was calculated with a compensating polar planimeter and will he referred to as the bird’s maximum utilized territory. A redstart’s activities appeared to he restricted to this specific area and it advertised its presence within it by singing. Although not enough territorial disputes were ohseiwed to state clearly that this entire area was defended in the strictest sense, all observed intrusions by other male redstarts were repulsed by the owner of the utilized territory. In both the pre-mating and post-mating phases, the redstarts were observed during the playing of the stimulus tape in the center of each bird’s maximum territory, and somewhere on the periphery of the territory. Approximately 24 hours separated the peripheral and center playback experiments for each bird. All the experiments were conducted between 07:00 and 11:00 edt, and the time for each series of playbacks for a given bird was kept as constant as possible (i.e., within a range of two hours). When a bird had moved into a desired location for a playback, the speaker was placed on the ground about 50-100 feet away from the bird. After the eciuipment was set up the bird was watched for six minutes, during which its vocalizations and distance from the speaker were noted. If the bird remained within 50-100 feet of the speaker during this period, the six-minute stimulus tape was played. After each stimulus song the location of the bird in relation to the speaker was noted as were his vocalizations. The next day before an experiment was initiated, the bird was observed for 30 minutes to be sure no changes in territory size had occurred and that the bird had not acquired a mate. During phase II (post-mating), the movements of the male redstarts were obseiwed for approximately an hour before the first playback was conducted and shifts in the shape Irkes and Ficken REDSTART TERRITORIAL BEHAVIOR 169 Table 1 Appuo.acii Latency Bird Pre-mating Post-mating Periirhery Center Periphery Center A 036)* 036)* 24 16 B 6 13 23 29 C 33 11 19 4 D 10 5 (NE)** (NE)** E 13 4 8 6 F 9 12 17 12 G 31 4 16 15 H 036)* 036)* 036)* 036)* I 6 9 3 10 J 1 2 2 8 K (NE)** (NE) ** 4 3 Median 11.5 10 16.5 11 60 percentile 6-33 4-13 4-23 6-16 * No approach within 30 feet during 36-song playback experiment. ** No experiment performed. No significant differences between paired comparisons. and maximum size of the territory were noted. The peripheral and center playback procedure in this set of experiments was the same as that used during phase I ( pre-mating) . During the course of the six-minute playback, a reactive redstart would fly toward the speaker usually giving some type of vocalization. The bird would approach the speaker in an ambivalent manner, moving closer and then farther away, occasionally flying over it. The exact nature of the response was variable: some birds would approach the speaker almost immediately, others would not; some would sing each time the stimulus song occurred, while others were considerably less vocal. Therefore, three criteria of responsiveness were used: the number of songs played back before the l)ird approached within 30 feet of the speaker (approach latency), the number of songs played back during which the bird was within 30 feet of the speaker (approach duration), and the number of times a bird flew over the speaker divided by the number of songs played back during which the bird was within 30 feet of the speaker (flights over speaker). The criteria, flights over the speaker was handled this way in order to maintain the independence of the three criteria. In other playback studies, variants of these criteria have been utilized (e.g., Weeden and Falls, 1959). With the use of the Wilcoxon matched-pairs signed-ranks test, a comparison was made between the birds’ responses to peripheral playbacks and their responses to center play- backs. The data obtained during pre-mating and post-mating were treated separately and a comparison of peripheral versus center responses was carried out for each criterion. RESULTS Measures of responsiveness. — The data for the redstarts’ responses are shown in Tables 1-3. Eleven birds were tested: nine birds were tested during pre-mating and post-mating; one was tested only during pre-mating (it 170 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 2 Approach Duration Bird Pre-mating ** Post-mating Periphery Center Periphery Center A 0 0 7 10 B 16 24 9 8 C 4 6 4 29 D 20 27 (NE)* (NE)* E 4 6 29 6 F 4 16 3 8 G 6 21 13 22 H 0 0 0 0 I 12 6 20 12 J 12 24 35 27 K (NE)* (NE)* 33 34 Median 5 11 11 11 60 percentile 3-12 6-24 4-29 8-27 * No experiment performed. ** 0.05 > p > 0.02 ( Other paired comparison not significant. ) Table 3 Flights Over Speaker Bird Pre-mating ** Post-mating Periphery Center Periphery Center A 0 0 0.14 0.20 B 0.06 0.08 0.22 0.25 C 0.25 0.33 0.25 0.14 D 0.20 0.56 (NE)* (NE)* E 0.25 0.17 0.17 0.17 F 0.50 0.63 0.33 0.38 G 0.17 0.33 0.15 0.09 H 0 0 0 0 I 0.17 0.50 0.10 0.08 .1 0.67 0.79 0.34 0.30 K (NE)* (NE)* 0.12 0.24 Median 0.185 0.33 0.16 0.185 60 percentile 0.06 0.25 0.08-0.56 0.12-0.25 0.09-0.25 * No experiment performed. ** 0.0.5 > p > 0.02 (Other jjaired comparison not significant.) Ickes and Ficken REDSTART TERRITORIAL BEHAVIOR 171 Fig. 1. Sketch map depicting maximum territories of unmated birds (pre-mating). The letters denote the birds identified in Tables 1-4. The black dots represent the trees a redstart visited during the one-hour observation period. abandoned its territory and another bird was substituted and tested only during post-mating) . The data for approach latency (Table 1), showed no significant difference between the responses to peripheral and center playbacks either during pre- mating or post-mating. During pre-mating there was a significant difference in approach duration (0.05 > p > 0.02) between the birds’ responses to peripheral and center playbacks. They remained within 30 feet of the speaker for a longer period of time during the playbacks in the center of their terri- tories. Similar results were obtained for the flights over the speaker criterion (Table 3). During pre-mating there were slightly hut significantly more (0.05 > p > 0.02) flights over per unit time in response to center play- backs compared to peripheral playbacks. During post-mating there was no significant difference between the responses to peripheral and center play- backs either in approach duration or in the number of flights over per unit time. Maximum territory size and shape. — Eigures 1-2 are examples of the 172 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 I I 120 FT Fig. 2. Sketch map depicting maximum territories of mated birds (post-mating). The letters denote the birds identified in Tables 1-4. The black dots represent the trees a redstart visited during the one-hour observation period. The X indicates the approximate area occupied by a very late arriving bird not considered in this study. sketch maps which show the territories the male redstarts held, and the territory size of each bird before and after mating is given in Table 4. The mean size before mating was 1.49 acres, and after mating was 1.13 acres. Lor six birds the territory size before mating was larger than after mating, the size of one bird’s territory increased after mating, and in two birds there was no observed shift in territory size. The mean amount of shift in territory size for these nine birds was -0.32 acres. DISCUSSION Before a redstart acquired a mate, there was a significant difference be- tween the defense of a territory’s periphery and its center in two of the approach measures of responsiveness. The approach responses of the male in the center of his territory were more aggressive than those in the periphery (i.e., he remained near the speaker longer and flew over it more often per unit time in the center). However, between the lime of pair formation and Ickes and Fickeu REDSTART TERRITORIAL BEHAVIOR 173 Table 4 Territory Sizes Size before mating Size after mating Amount of shift in size Bird acre.s acres acres A 1.24 0.84 -0.40 B 1.57 1.29 -0.28 C 1.97 1.32 -0.65 D 1.77 * — E 2.01 1.41 -0.60 F 2.26 1.45 -0.81 G 1.17 0.92 -0.25 H 0.66 0.77 +0.11 I 1.00 1.00 0 J 1.24 1.24 0 K ❖ 1.09 — Mean 1.49 1.13 -0.32 * No observations. the end of nest building (post-mating), the redstart defended the periphery and the center of its territory about equally. Table 2 suggests that post- mating responsiveness is more like the intense pre-mating responsiveness at the center than the less intense reactions at the periphery. The fact that a bird will defend its territory with increased vigor the nearer an intruder approaches its center has been noted on a number of occasions (e.g., Lorenz, 1938; Bremond, 1963), and this might be the type of reaction observed in this study. However, this does not explain why the redstarts were more aggressive in the center of their territories during pre-mating, while they defended the periphery and center of their territories equally during post-mating playbacks. If redstarts normally spend more time in the center of the territory than in the periphery, the observed difference in response could be due to something completely unrelated to the playback expriments. There have been some ob- servations made concerning any normal tendency the redstart may have to re- main in either the center or periphery of its territory. The redstarts observed liy Hickey (1940) seemed to move back and forth in an indefinite and irregular pattern covering the extent of their territories, and Eicken (1962) has stated that early in the season redstarts “seem to spend no more time at the center than at the periphery” of their territories. The sketch maps of the unmated birds observed in this study (c.g.. Figure 1) seem to illustrate this lack of a preference for the center of a territory in the redstart. The locations a bird visited and sang from were distributed evenly between tbe center and periphery of its maximum territory. Perhaps the redstarts were more aggressive in the center of their territories 174 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 because of previous experience in these areas. Morse (1966) found that the locations of past encounters were an important factor in determining what type of song Yellow Warblers { Dcndroica petechia) would sing in particular parts of their territories. If the redstart s maximum territory is composed of a number of small areas which will differ in their importance to the biid based upon earlier experience there, the bird s responses to playback in different areas would be dependent upon the history of the bird s relation to its territory. However, it is unlikely that a bird s past experience in a given area was the main reason for the difference in aggressiveness observed in this investigation. The possibility of playing the stimulus tape in a locality of little importance was reduced by selecting areas for playback experiments in which the redstarts had been seen frequently during the one-hour observa- tion periods. Also, the pre-mating playbacks were conducted very early in the season which minimized the effect of past experience on the playback experiments. The breeding condition of the bird would probably have its effect on terri- torial behavior. A decrease in territory size might also produce changes in territorial behavior. Huxley (1934) has stated that territories are like “rubber discs”; the more they are compressed, the stronger becomes their resistance against further compression. Lurthermore, these two factors may be correlated. All the birds with the largest territories (1.6-2. 3 acres) were unmated; four of the five birds with the smallest territories ( 0.8-1. 1 acres) were mated. Of the seven birds whose territory size was known during pre-mating and post-mating, six showed a decrease in size after acquiring a mate (Table 4). Apparently, the size of a redstart’s territory is less during post-mating than before a mate is acquired. Although a causal relationship does not necessarily exist, there does appear to be a correlation between territory size and breeding condition. Therefore the effect of these two factors on the redstart’s responses to playback could not be separated. In order to define more carefully the role of each of these factors in the redstart’s defense of its territory, a larger sample size would be needed with a number of birds in the same stage of the reproductive cycle occupying different sized territories. During the course of this study each redstart was not observed every day; therefore, the exact date each territory decreased in size could not be de- termined. It is possible that some of the territories were compressed before the females arrived and in these cases there might not have been any relation- ship between matedness and territory size. Assuming the territory size would have decreased regardless of the bird’s breeding condition the “rubber disc” theory would apply to the redstart’s equal defense of its entire territory after this decrease. To determine if this compression of the redstarts’ territories Ickes and Ficken REDSTART TERRITORIAL BEHAVIOR 175 and not their breeding condition was the reason for equal defense in both the center and periphery, a number of birds would have to be continuously observed and the territory size recorded daily. It appears that the problem of analyzing the redstart’s territorial behavior utilizing a playback technique is considerably more complex than initially anticipated. The factors which help to determine this bird’s aggressive activities appear to be interacting in a number of ways and are quite difficult to isolate. The observed shifts in territory size and shape noted in this study appeared to be caused by several factors. The territories of Birds A, B, and C (Figs. 1-2 ) were reduced at least in part by the addition of late arriving males. In two cases first-year males were able to overcome the aggressiveness of the original territory owner, acquire some of his territory, and obtain a mate. In the only instance where a redstart increased the size of his territory after mating, the location of the female’s nest appeared to determine the final size and shape of the territory. Apparently the female has ultimate control over the location of the territory boundaries and if she chooses to nest outside the male’s original territory, the male expands his territory to include the area around the new site (Ficken, 1962). In two of the birds there were no noticeable differences in their territory sizes before and after mating. This seemed to be due to the limitations of the area where they first arrived; during pre-mating they were bounded by roads and neighbors on all sides. The shifting of territorial boundaries in the American Redstart has been observed by other investigators (Sturm, 1945; Ficken, 1962). In this study the upper limit of population density probably was not achieved; denser populations were accommodated by a compression of territories (e.g., the area occupied by three birds during pre-mating (Fig. 1), was supporting five birds during post-mating (Fig. 2) ). Several other ways territorial birds might accommodate a denser population are: (a) expand into less suitable habitats, (b) allow the territories to overlap (Weeden, 1965), and (c) increase the vertical foraging range (Ficken, pers. comm.). The redstarts studied here did not appear to utilize any of these other methods. SUMMARY Territorial behavior in the American Redstart was investigated l)y playing a recorded redstart song in the center and on the periphery of a male bird’s maximum utilized territory. The bird’s responses to the playbacks were observed and analyzed in order to determine what effect breeding condition, size of territory, and location of playback have on territorial defense. One series of experiments was conducted before a male had acquired a mate; a second series was run after a mate had been acquired. During pre-mating the center was defended more vigorously than the periphery; during post-mating the center and periphery of a territory were defended equally. Some of the factors that might have been interacting to bring about this differential aggression were 176 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 discussed with no definile decision reached as to which were ll.e most important; how- ever, there was sufficient evidence to suggest that the redstart’s past expeiience an normal activities were not particularly relevant. The maximum territory of a redstart appeared to shift in size and shape between the time a male arrived and the end of nest building; usually a decrease m size occurred. ACKNOWLEDGMENTS We wish to thank Dr. J. P. Mailman for his assistance with the statistical analyses of the data in this research and his very constructive suggestions and criticisms concerning this manuscript. Special thanks are due the senior author’s wife, Judi, whose patience and assistance in the field and during the writing of the manuscript was incalculable In addition, we would like to thank Dr. R. W. Ficken for his assistance in the field and helpful suggestions. This study was aided in part by National Science Foundation Grant GB 6100. LITERATURE CITED Armstrong, E. A. 1965. Bird display and behaviour. Dover Pubh, Inc., New York. Bremond, J. C. 1963. Acoustic behaviour of birds, p. 709-750. In: Busnel, R. G. (Ed.), Acoustic behaviour of animals. Elsevier Publishing Co., Amsterdam. Ficken, M. S. 1962. Agonistic behavior and territory in the American Redstart. Auk, 79:607-632. Ficken, M. S. 1963. Courtship of the American Redstart. Auk, 80:307-317. Ficken, M. S. and R. W. Ficken. 1965. The comparative ethology of the Chestnut-sided Warbler, Yellow Warbler, and American Redstart. Wilson Bulk, 77:363-375. Griscom, L.’ and a. Sprunt. 1957. The warblers of America. Devin-Adair Co., New York. Hickey, J. J. 1940. Territorial aspects of the American Redstart. Auk, 57 :255-256. Huxley, J. 1934. A natural experiment on the territorial instinct. Brit. Birds, 27: 270-277. Lorenz, K. 1938. A contribution to the comparative sociology of colonial-nesting birds. Proc. 8th Intern. Ornithol. Congo, 207-218. Morse, D. H. 1966. Tlie context of songs in the Yellow Warbler. Wilson Bulk, 78: 444-455. Stein, R. C. 1963. Isolating mechanisms between populations of Traill’s Flycatchers. Proc. Amer. Phil. Soc., 107:21-50. Sturm, L. 1945. A study of the nesting activities of the American Redstart. Auk, 62: 189-206. Tinbergen, N. 1957. The functions of territory. Bird Study, 4:14-27. Weeden, j. S. 1965. Territorial behavior of the Tree Sparrow. Condor, 67:193-209. Weeden, j. S. and j. B. Falls. 1959. Differential responses of male Ovenbirds to recorded songs of neighboring and more distant individuals. Auk, 76:343-351. department of zoology, university of MARYLAND, COLLEGE PARK, MARY- LAND (present address (r.A.l), biology department, WASHINGTON & JEFFERSON COLLEGE, WASHINGTON, PA.; (m.S.F.), UNIVERSITY OF WISCONSIN- MILWAUKEE, MILWAUKEE, WISCONSIN), 13 MARCH 1968. THE WINTER TERRITORIES OF TUFTED TITMICE Ralph W. Condee The winter behavior of Tufted Titmice [Parus bicolor) raises many questions. This study attempts to answer three: (1) What area does an individual titmouse cover during its normal winter activities? (2) What relation does the winter area covered hy one titmouse bear to that of the other titmice in the general locale? (3) To what extent do titmice associate in flocks with a stable membership, and in flocks of what size? methods The basis for the answers is the observation of 20 color-banded titmice for varying periods during a seven-month span (1 September 1967 to 1 April 1968). These birds inhabited the southeast slope of Mount Nittany, in Centre County, Pennsylvania, near the town of State College. The study area was 5400 feet long (from southwest to northeast) and 1800 feet wide (from southeast to northwest). The elevation ranged from 1300 feet above sea level (the southeast edge) to about 2000 feet (the ridge of Mount Nittany at the northwest edge). About 20 per cent of the land is open pasture hounded by hedgerows of hawthorn, maple, black walnut, etc.; about 25 per cent is mixed oak forest ranging up to 80 feet in height, with little understory. About 40 per cent of the land, chiefly in a strip along the mountain, is mature deciduous forest — mixed oak, maple, and walnut, with an understory of dogwood, wild grape, etc., un- broken for more than the 5400 feet of the study area, and extending 600 feet down the mountain into the study area. About 15 per cent of the land is cut-over brushy woods, consisting mainly of immature mixed oak, maple, walnut, dogwood, hawthorn, wild grape, bittersweet, etc. Several techniques and “rules” for locating the titmice were necessary in order to avoid the effect of a feeding station, which might distort the normal winter behavior of the birds. Four (occasionally five) traps operated simultaneously. Each trap was a Potter type, one-, two-, or three-celled, suspended from a tripod made Ijy wiring together three eight-foot metal clothespoles. The traps were baited with about a cup of sunflower seeds (occasionally suet), and pinned open when not in use, thus function- ing also, temporarily, as feeding stations. Every trap was moved to a new location every time it caught a titmouse. The only exceptions were instances where a two- or three-celled trap caught additional titmice before I could return to the trap in my rounds. The purpose of moving the traps in this fashion was to reduce any “feeding-station effect” which might distort the birds’ territories. Every trap was moved to another location at least every eight days whether or not it caught a titmouse. Since the traps were pinned open when not in use, they still might entice birds out of their normal territories, even though no I)irds had been trapped. All traps were moved at least 100 yards and were not returned to a prior location, or within 100 yards of a prior location, until at least 13 days had elapsed. Ihe eight-day and 13-day periods have no ornithological significance; tliey simply fit easiest into a pattern of weekend handing. In addition to trap-records, many birds could of course be traced by their color-bands. 177 178 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 RESULTS Nineteen titmice were trapped and color-banded; in addition one unbanded titmouse avoided the traps late in the study period. The trappings and observa- tions produced 141 place-time records. Of the 19 banded birds, 10 were adults in the autumn of 1967; of these, two were birds banded in the winter of 1965-66, five were banded in the winter of 1966-67, and three were adults first seen in the winter of 1967-68. The basis for distinguishing adults from immatures was mouth-color: light gray upper bill, immature; dark gray, adult (this is based on an unpublished manuscript of Professor Merrill Wood I . In addition to the 10 known to be adults, two birds were of unknown age, being trapped too late in the winter of 1967-68 to have shown immature characteristics. Seven of the 19 were immatures in the autumn of 1967. Sexing was done by wing-chord measurement ( based on an unpublished manuscript of Professor Merrill Wood) : 78 mm or less, female; 79-82 mm, unknown; 83 and over, male. Six of these birds were male, five were female, and eight of unknown sex. In March 1968 the weight of nine birds averaged 22.6 grams (extremes: 20.6, female, to 24.0, one male and one of unknown sex). The 14 titmice of Laskey (1957) in Tennessee averaged 20.5 grams; the 35 titmice of Nice ( 1933 ) in Ohio ranged from 20.3 to 25.3 grams. Ligure 1 shows the large patterns of the inter-relations of the titmice. In the study area there apparently were no more than 20 titmice during the period of the investigation: 19 color-banded birds and one unbanded bird seen once, 22 March 1968, at the lower right corner of Area A. DISCUSSION The titmice divided themselves into four “clans,” designated in Ligure 1 as A, B, C, and D. A term such as “clan” seems preferable to “flock” for two reasons: (1) because Gillespie (1930 ), Van Tyne ( 1948 ), and Laskey (1957) observed that the association of titmice during the winter season was a vestige of the family group of the previous season; (2) because an observer seeing a group or “flock” of titmice in certain parts of the area ( specifically the overlaps in Ligure 1) might be seeing titmice which normally group together (a “clan”), or he might be observing a mixed group from two different clans, birds which would soon separate as they moved to other parts of their respective territories. The composition of each clan was as follows: Clan A — five birds: one male, age unknown; one adult male; one female, age unknown; two adults of unknown sex. Clan B — three birds: one adult male; one immature male; one immature female. Clan C — six birds: one adult male; one adult female; one immature female; three of unknown sex, one of them mature, the other Ralph W. Comiee TITMOUSE WINTER TERRITORIES 179 Fig. 1. Winter Territorial Boundaries of 19 Tufted Titmice. Territory A: five birds. B, three birds. C, six birds. D, five birds. two immature. Clan D — five birds: one adult male; one immature female; three of unknown sex, one of them adult, one immature, and one of unknown age. In addition, as has been pointed out, there was one unhanded titmouse observed on 22 March 1968 in a part of the area visited by both Clans A and B. Except in one instance, birds of a given clan were never observed outside the territories indicated by the letters A, B, C, and D in Eigure 1. The 180 THE WILSON BULLETIN June 1970 VoU 82, No. 2 boundaries in Ligure 1 rest on 141 observations and two assumptions: (1) that the territory indicated is the minimum for each clan; (2) that the boundaries of the territory can be determined roughly by drawing lines from one observed point to another along what seem to be the outermost points of the territory. These are not, then, observed boundaries; in most instances a titmouse at the territory’s “edge” — if indeed it was an edge — flew toward the central area of the territory and not in any path that might be called a perimeter of the territory. Offutt (1965) reports that “[breeding] territory appeared to extend from about fifteen feet above the ground to the treetops.” This does not seem to he true of wintering territory. In winter the titmice associated with their clan at various heights and, except for the areas of overlap, almost invariably stayed away from other territories. The maximum observed distance covered by any titmouse during the period of observation was approximately 3000 feet; 185, a female of Clan B, banded as an immature on 16 September 1967, was trapped at the northern- most limit of Territory B on 23 September 1967, and at the southernmost limit of Territory B (3000 feet away) on 26 March 1968. In Clan C, 187, of unknown sex, was trapped at the northernmost point in the territory on 29 Lehruary 1968, and at the southernmost, 2400 feet away, on 31 March 1968 — the maximum distance for a titmouse of this clan. Territory D is at least 2500 feet long ( its northernmost limit is known only to the titmice ) , hut I found no one titmouse ranging the whole length of the territory. Nice (1933) writes that her flock of 8 birds ranged over about 20 acres. Since these observations began well after the end of the breeding season, I can say nothing definite about the relations of the titmice within a clan. Laskey (1957) writes, “My [winter] records . . . indicate that the twosomes may be a mated pair, but not always. They may be birds hatched the previous summer, probably of the same brood, or a parent and a youngster. The small groups may be a family or a brood. I have not seen large groups.” This would indicate the internal structure of Clan B as being a male parent with a male and a female offspring. But the internal relations of the other clans are not clear since each has three adults in it. There are at least two possibilities: (1) that the clans are coalitions of the remnants of several summer families; (2) that the clans are really associations of smaller groups, and that my observations failed to detect the existence of these “septs” within the clans. Lor example, 794 ( an adult of unknown sex) apparently never strayed outside Territory C; but it also never seemed to wander throughout all of C. Its appearances were limited to an east-west strip through the middle of Territory C. 136 ( an adult male ) ranged through the middle and northern parts of Territory C, but not to the Ralph V. Condce TITMOUSE WINTER TERRITORIES 181 southern part. On the other hand, 187 (an immature of unknown sex) turned up almost everywhere within Territory C. Previous handing of titmice (1965-67) at a fixed banding station in this area had resulted in a small number of returns at the end of the breeding season: of the 15 titmice banded between 15 September 1965 and 22 March 1966, only one returned during the winter season of 1966-67. The other 17 birds trapped that winter were previously unhanded. In 1967-68, scattering the traps and widening the area of observation resulted in the return of three of the titmice from previous years, all of them in Territory A. With the exception of one observation, they never ventured as close as 1200 feet to the feeders and traps they had visited during previous winters. The previous ( fixed ) banding station had been in the area where (in Eigure 1) Territories B and C overlap. One titmouse had appeared three times at this banding station in the spring of 1966, but it never came within 1500 feet of this site in 1967-68. Another bird had appeared 11 times at the banding station during the winter of 1966-67 ; it appeared there only once (15 March) in the winter of 1967-68. That trip is the only instance of one of these 19 birds moving outside the territorial boundaries of Figure 1 during the winter of 1967-68. A third titmouse had appeared twelve times at the 1966 banding station, but it never appeared in this territory at all in 1967-68. Although it was commonly evident during this period in Territory A, it always remained at least 1200 feet from its previous haunts. A similar phenomenon was noted by Short (1933) and Van Tyne (1948). With regard to these movements from year to year. Van Tyne suggests that there are two classes of titmice: those that remain in restricted home ranges throughout the year ( hence repeatedly recorded in a small radius ) ; B, those that wander (hence not recorded after banding) . It seems reasonable to suppose that the former are fully adult birds; the latter, birds in their first winter wandering widely before settling on a home range.” On this point A. C. Bent (1946) quoted Dr. Dickey (MS.) who, “referring to Pennsylvania and West Virginia, says, ‘Particularly in autumn and winter, tufted tits are rovers. . . . Bands . . . enter patches of weeds, flit along the courses of streams, cross country roads and highways, and peer forth from cover at farmyards.’ . . . Several other observers have reported winter wander- ings of titmice.” But this does not seem to account for the shift I observed between 1966 and 1968. Take two titmice — 165 (adult, sex unknown) and 166 (adult male) as examples: I do not know if 1966—67 was their first winter, hut they seem not to have been “wandering.” Together they clocked 23 appearances at the banding station that winter. And their abandonment of their old territory in 1967-68 was almost total, while their adherence to their new territory was 182 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 quite close. The record for 017, an adult of unknown sex (banded 17 March 1966) points in the same direction, although there are fewer observations. This behavior looks less like wandering and more like a clearly defined immigration into a new winter territory. But some titmice are apparently closely attached to a territory from year to year. Lor example 794, of unknown sex, was trapped in precisely the same spot on 14 October 1965 and 10 Lebruary 1968. It was trapped only 300 feet away from this spot on 20 November 1966, 26 April 1967, and 25 Lebruary 1968. Some titmice never leave “home,” and others apparently shift their base of operations to a nearby area and never, or rarely, return even the short distance of 1200 feet to their previous territory. My observations markedly disagree with those of Bent’s informants. My titmice seemed to move as a group with the same “clan” (family?) and within a defined territory. There was no evidence of “wandering.” Certain clans seemed reluctant to approach each other. The area between A and C produced no records of either clan, and that between C and D produced very few records, although both areas were intensively trapped and observed. On the other hand I did find considerable overlapping in two areas. The point at which B and C overlap (in the center of Ligure 1), and A and B overlap (at the bottom of Ligure 1) can be described simply as areas with lots and lots of titmice around a great deal of the time. I could see no signs of conflict or territorial clash. It is probably significant that the point where B and C overlap was an excellent area for food — wild grape, hawthorn, bittersweet, oak, etc. And the area was visited by seven titmice: four from Clan C and three from B. SUMMARY Nineteen color-banded Tufted Titmice were trapped and observed on a tract 5400 feet by 1800 feet in the seven months from 1 September 1967 to 1 April 1968 in order to observe winter territorial activity. They restricted themselves to four territories with five, three, six, and five birds per territory. The territories seemed to be of irregular shape, making total areas impossible to state. The maximum distance between two points within one territory was 3000 feet. At two points territories were contiguous and few or no titmice were to be found; at two other points territories overlapped and the number of birds was quite high. No conflicts or territorial clashes could be seen. One clan of five titmice included three birds which had occupied another (nearby) territory one or two winters before, but which now remained almost completely outside their previous territories and within their new territory. Adherence to territory was close. ACKNOWLEDGMENTS 1 am indebted for information, advice, and help to Professor Merrill Wood, Dr. James Lindzey, and Miss Dorothy Bordner of the Pennsylvania State University, to Professor David Davis of the University of North Carolina, and to Mr. George C. Offutt of the Ralph \\h Contlee TITMOUSE WINTER TERRITORIES 183 University of Rhode Island. In addition I am grateful to my neighbors on the Blackhawk Road — Dr. and Mrs. Russell Murphy, Mr. and Mrs. John Dittmar, Mr. and Mrs. Paul Brooks, Mr. and Mrs. James Brooks, and Dr. and Mrs. James Lindzey, who kindly permitted me to trap and observe the titmice on their land. LITERATURE CITED Bent, A. C. 1946. Life histories of North American jays, crows, and titmice. U. S. Natl. Mus. Bulk, 191. Gillespie, M. 1930. Behavior and local distribution of Tufted Titmice in winter and spring. Bird-Banding, 1:113-127. Laskey, A. R. 1957. Some Tufted Titmouse life history. Bird-Banding, 28:135-145. Nice, M. M. 1930. Winter range of Tufted Titmice. Wilson Bulk, 45:87. Offutt, G. C. 1965. Behavior of the Tufted Titmouse before and during the nesting season. Wilson Bulk, 77:382-387. Short, M. 1933. Some Tufted Titmice history. Bird-Banding, 4:159-160. Van Tyne, J. 1948. Home range and duration of family ties in the Tufted Titmouse. Wilson Bulk, 60:121. DEPARTMENT OF ENGLISH, THE PENNSYLVANIA STATE UNIVERSITY, UNIVERSITY PARK, PENNSYLVANIA. 14 MAY 1968. FOOD HABITS AND FEEDING BEHAVIOR OF THE BALTIMORE ORIOLE IN COSTA RICA Richajrd L. Timken Baltimore Orioles [Icterus galbula) are mainly insectivorous during their summer residence in North America (Bent, 1958), but little is known of their food habits while wintering in Central America and northern South America. Slud (1964) mentions that this bird has a varied behavior and diet while in Costa Rica, and A. F. Skutch is reported as saying that Baltimore Orioles subsist on a variety of animal and plant foods ( Bent, 1958). However, no qualitative or quantitative data are available concerning the food habits and feeding behavior of this species. In Costa Rica the species occupies a wider range of habitat than do the native orioles and exceeds them in total numbers (Slud, 1964). This study was undertaken to obtain some data concerning the habits of this successful species during its stay in Costa Rica. MATERIALS AND METHODS This study was conducted at seven different sites in five of the seven Costa Rican Provinces. Collections were obtained at: Tahoga, Guanacaste Province; Heredia, Heredia Province; Turrialha, Cartago Province; and San Isidro, San Jose Province. Observations of feeding behavior were obtained at the collection sites and at three other sites: San Jose, San Jose Province; San Vito, and Rincon, Puntarenas Province. Birds were collected with shotguns at different hours on several dates. Stomachs from collected specimens were removed as quickly as possible, slit and preserved in a 70 per cent ethanol solution. The number of each item was recorded per stomach and the per cent by volume of each kind of food item was estimated. RESULTS AND DISCUSSION Observations of Feeding Times and Activity. — This species frequents borders and boundaries of many types of broken habitats. It is found foraging for food mainly in the canopy, but frequently is found at lower levels. Many times it is found in loose aggregations of birds such as other native and migrant icterids, tanagers, hummingbirds, etc. Associations with par- ticular plants seem to he part of the feeding behavior of the species. Baltimore Orioles usually become active as soon as it begins to get light in the morning. Within a few minutes of dawn, large numbers of orioles are actively foraging in the canopy layer of the habitats that they are utilizing. Active foraging generally occurs between 06:00 and 08:00. Reduced feeding activity may last until 11:00 or even later, but by 09:00 most Balti- more Orioles have finished feeding and after 11:00 virtually all are resting 184 Kiclianl L. Timken BALTIMORE ORIOLE WINTER EEEDING 185 Food Items of Sample 1 CuANACASTE PROVINCE, Table I (21 Stomachs) Costa Rica — 8- Collected at -12 February Taboca, 1968. No. of Mean no. of Mean est. Food item stomachs items per per cent by with item stomach vol. per stomach Animal material Lepidoptera larvae 17 19 61 Coleoptera 8 1 9 Formicidae 3 2 4 Odonata 3 1 2 Ortlioptera 1 0 0 Diptera and larvae 5 0 2 Hemiptera 1 0 0 Insect egg cases 3 0 1 Plant material Olyra seeds 2 1 8 Sideroxylon fruit 1 0 1 Unidentified material 18 — 12 someAvhere in the shade. On cloudy days the entire sequence seems to be retarded and feeding activity may last later into the morning. Later a second period of activity occurs, usually beginning about 16:00 and lasting until dark. This feeding period appears to be less intense, as fewer orioles are observed. Those that are observed seem to feed less actively than they did during the early morning period. On cloudy days this second feeding may commence and end early in the day. Observations of Feeding and Plant Associations. — In northwestern Costa Rica during the early morning active feeding period, large numbers of Baltimore Orioles were observed visiting Sideroxylon trees. These trees were flowering and fruiting, but also had heavy foliage. Large numbers of bees, hummingbirds, and warblers were also visiting these trees. As many as 12 to 15 Baltimore Orioles could be observed actively feeding in the tops of these trees, but by 08:30 almost all oriole activity ceased. On one occasion a large group of orioles (8 or 10 birds) was observed foraging in a Caly- cophyllum candidissimuin tree which had heavy foliage. A few orioles were observed drinking nectar from Combretum flowers and foraging in this vine during the early feeding period. After 08:00 and until 11:00 large numbers of orioles visited Combretum vines. A few were seen drinking nectar from these vines, but most were either resting or foraging for insects. The most active feeding period, however, seemed to be during the time spent in the Sideroxylon trees. During the afternoon period some orioles were observed 186 THE WILSON BULLETIN J line 1970 Vul. 82, No. 2 Table 2 Food Items of Sample 2 (18 Stomachs) Collected at Turiualba, Heredia, Heredia Province; and San Isidro, San Jose Province Cartago Province; — 4-8 March 1968. Food item Sub-sample A 4—6 March Turrialba ( 7 stomachs ) Snb-sample B 7 March Cartago ( 6 stomachs ) Sub-sample C 8 March San Isidro ( 5 stomachs ) No. of stomachs with item Mean no. of items/stomach Mean est. per cent vol. /stomach No. of stomachs with item Mean no. of items/stomach Mean est. per cent vol. /stomach No. of stomachs with item Mean no. of items/stomach 1 Mean est. per cent vol. /stomach Animal material Lepidoptera larvae and pupae 5 2 26 6 6 54 3 6 30 Coleoptera & larvae 6 6 44 3 1 4 5 6 46 Hymenoptera 2 1 5 0 0 0 2 1 4 Formicidae 0 0 0 0 0 0 2 1 1 Orthoptera 2 0 10 0 0 0 2 0 2 Diptera & larvae 0 0 0 1 0 5 1 0 0 Hemiptera 1 0 1 0 0 0 2 1 3 Insect egg cases 1 1 1 2 1 7 2 2 6 Araneae 0 0 0 2 1 3 1 0 0 Plant material Ficus fruit 0 0 0 2 0 15 0 0 0 Unidentified material 7 - 14 5 - 12 5 - 8 feeding in Combrelum, Biirsera simaruba, and Enter olobiiim cyclocarpum : in one instance a few orioles were observed foraging in epiphytic bronieliads. 1 his activity also seemed to be reduced in intensity^ compared with the early morning feeding in Sideroxylon trees. Observations ruade in central Costa Rica indicated that Baltimore Orioles foraged for food in trees with bright colored flowers or in trees with heavy foliage. Most Baltimore Orioles in this region were seen during the early morning activity period foraging in Erythrina poeppigiana trees which had bright orange flowers and were nearly devoid of leaves. Some Baltimore Orioles were observed in other Erythrina spp. and in Cassia grandis. A few orioles were observed in Cordia alliodora trees which were in flower and had heavy foliage. In southwestern Costa Rica fewer numbers of Baltimore Orioles were seen. A few orioles were observed foraging in Cecropia spp. and Eicus sp. which were in fruit. One male was seen eating from a Cecropia fruit but spent most Ricliani 1.. TinikfU BALTIMORE ORIOLE WINTER FEEDING 187 Table 3 Summary of Important Food Items Found in 38 Baltimore Oriole Stomachs Collected During February and March, 1968 in Costa Rica. Total number Mean number Mean estimated Food items of items of items irer cent by volume Animal material Lepidoptera larvae & pupae 482 13 49 Coleoptera and larvae 100 3 19 Other insects and araneae 128 3 12 Plant material 36 1 7 Unidentified material — — 12 Total 746 20 99 of his time foraging for insects. One oriole was observed foraging high up in a large Brosimum utile tree which was in fruit and had heavy foliage. Baltimore Orioles observed in the three regions either were seen actively foraging in trees with heavy foliage or were observed in vegetation with bright red or orange-colored flowers such as Comhretum plants or E. poep- pigiana trees. Orioles foraging or resting in these plants with brightly colored flowers seemed to be much less active and remained for longer periods of time than those orioles observed in other non-colorful vegetation. Therefore, the possibility exists that these plants not only provide food but also provide a cryptic situation for the brightly colored male Baltimore Oriole. Stomach Contents Analysis. — Tables 1, 2, and 3 summarize the results of the analyses of stomach contents. It is readily apparent that Lepidoptera larvae and coleopterans make up the most important components of the diet of these winter residents. However, a wide variety of animal species and a few plant fruits were utilized as part of their diets. Lepidoptera larvae appear to be the most important item in the diet of this bird while it is in Costa Rica. Beetles are the next most important part of the diet. However, as sub-sample A and sub-sample C indicate, in Table 2, in some cases beetles may be the most important. This diet information is strikingly similar to the known information concerning the diet of this bird in North America during its summer residence (Martin, Zim, and Nelson, 1951), (Bent, 1958). The similarity of diet between sub-sample A and sub-sample C of sample 2 is interesting. These sub-samples were collected at different locations, on different dates, at different hours of the day and had different sex-age compo- sition; the only equality of the sub-samples was that both sub-samples were obtained from populations of birds utilizing E. poeppigiana trees. 188 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 No differences in diet between sex and age groups were evident in this study. However, larger samples might show some differences because females and sub-adults seemed to feed over a longer period of time and utilized a wider variety of trees in their feeding behavior than did adult males. SUMMARY This study indicates that Baltimore Orioles feed early in the morning and to a lesser degree again in the late afternoon during their stay in Costa Rica. Baltimore Orioles tend to visit certain plants that are either in flower or fruit. Lepidoptera larvae are the most important fraction of this species’ diet and coleopterans are the next most important part, the two accounting for about 68 per cent of the total food. A variety of other insects and spiders made up 12 per cent of the diet. Plant material accounts for only 7 per cent of the total diet; 12 percent of the total volume of stomach contents was unidentified hut was composed mainly of fragmented insect remains. ACKNOWLEDGMENTS I wish to thank the Organization for Tropical Studies who furnished me with travel fare to and from Costa Rica. Sincere appreciation is given to Dr. Thomas Emniel and Barney Cornahy for their aid in stomach content identification. I wish also to thank the National Aeronautical and Space Administration for their support of my graduate program. LITERATURE CITED Bent, A. C. 1958. Life histories of North American blackbirds, orioles, tanagers, and allies. U. S. Natl. Mus. Bull., 211:255-259. Martin, A. D., H. S. Zim, and A. L. Nelson. 1951. American wildlife and plants. Dover Publ. Inc., New York. p. 172. Slud, P. 1964. The birds of Costa Rica. Bull. Amer. Mus. Nat. Hist., 128:342. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF SOUTH DAKOTA, VERMILLION, SOUTH DAKOTA. (present ADDRESS: DEPARTMENT OF BIOLOGY, WAYNE STATE COLLEGE, WAYNE, NEBRASKA), 3 JUNE 1968. EN ROUTE BEHAVIOR OF HOMING HERRING GULLS AS DETERMINED BY RADIO-TRACKING William E. Southern PROBLEMS associated with bird migration, spatial orientation, and navi- gation have stimulated considerable interest among biologists and others. During the last two or three decades increasing numbers of investi- gators have studied these problems, and their efforts have been greatly aided by the introduction of new sophisticated equipment and techniques. One of these recent approaches has been the application of radio-tracking equipment. This paper is the result of one attempt to use such equipment. Prior to the availability of telemetry equipment, experimental birds were only observable at release times, possibly for a short period thereafter, and occasionally upon return. Seldom was it possible to determine the actual routes taken by homing birds or their apparent responses to environmental clues while en route. Exceptions to this statement are Griffin’s and Hock’s (1949 ) airplane tracking of Herring Gulls {Larus argenlatus) and Gannets {Morns bassanus) and Hitchcock’s (1952) and Griffin’s (1952) airplane observations of pigeons {Columba livia). These data, however, were in- sufficient to indicate the procedures involved in avian homing. During the summers of 1963 and 1964, I conducted orientation experiments with 50 adult Herring Gulls, 323 adult and subadult Ring-billed Gulls (L. delaw are nsis) , 56 juvenile Ring-billed Gulls, and 294 Ring-billed Gull chicks from a colony near Rogers City (Presque Isle County), Michigan. My ob- jectives were: (1) to examine the orientation requirements of each species; ( 2 ) to evaluate the homing and orientation abilities of both species; and (3) to determine the behavioral mechanisms and environmental factors associated with orientation as performed by these species. METHODS Adult Herring Gulls were captured with nylon snares, color-marked with alcohol soluble biological stains, and subjected to typical homing trials. During 1964, the gulls were anesthetized with Equitol (4.5 ml/kg) and transported to release sites in burlap hags. This paper pertains to one aspect of the study, the behavior of 41 Herring Gulls that were radio-tracked during homing flights from release sites located up to 110 miles from the colony (Table 1). Tracking distances for individual gulls ranged from 3 to 138 miles. Seven other gulls were equipped with transmitters hut they were not tracked more than one mile because of transmitter failure, signal interference, or undetermined factors. The results discussed at this time are based on a total 1307 miles of radio-tracking and at least 285 radio-contact hours with experimental birds. The radio-tracking equipment used during this study and some of the problems associ- ated with the field application of this technique have been discussed previously (Southern, 1963, 1967). Two mobile units were used and each vehicle was manned by at least two 189 190 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 1 Summary of RELEASE Sites AND Success Rates for Radio-tracked Herring Gulls. Distance of Release Sites from Colony 10 20 30 40 50 60 80 110 miles miles miles miles miles miles miles miles No. tracked 5 14 4 4 4 3 4 3 No. returned 5 8 4 3 3 2 2 2 41 tracked; 29 returned; success rate 70.8 per cent. persons, a driver-receiver operator, and a recorder-map reader. One permanent station antenna was also maintained. Twenty-nine (70.8 per cent) radio-tracked Herring Gulls returned successfully (Table 4* ill periods ranging from 40 minutes (10 miles to release site) to 151 hours (30 miles). Eighteen of the 29 successful gulls were tracked during all, or most of their journey. The other returning individuals, and also those failing to home were tracked for periods ranging up to five hours. Their complete flights were not tracked for several reasons, e.g. : (1) a lack of adequate roads for use by tracking vehicles; (2) several gulls landed and remained at the same location for several hours and radio contact was eventually discontinued because of operator fatigue or other obligations; (3) prolonged flights by gulls in directions other than homeward resulted in the cessation of tracking operations; and (4) transmitter signals were lost as a result of human error, environmental factors, or equipment malfunction. Although several gulls were tracked over meandering routes of 100 or more miles, the farthest release site from which a gull’s entire homing flight was tracked was 60 miles. No attempt was made to initiate long-range trials since considerable information was available for Herring Gulls (Griffin, 1943; Matthews, 1952). I decided that the shorter tiials, up to about 150 miles outside of the normal feeding range, would provide con- sideiable data regarding the necessary environmental clues, homing success rates, and general orientat.on behavior. Results from such trials should also provide some in- formation regarding the factors associated with orientation during longer flights by this species. Results from various studies tend to substantiate this contention (Kramer, 1961). Regal dless of the type of homing study conducted, the conclusions which are drawn must always be restated in terms applicable to bird migration. RESULTS Flight patterns of successful homers. — Twelve (66.6 per cent) of the 18 Herrinp; Gulls that were tracked for significant distances pursued south, east, or southeast courses during early flight periods, i.e., after initial departure. I he other six gulls selected north (two), west (two), northeast (one), or southwest (one) as preliminary headings. The selected departure direction was often followed for a half mile or more before a change was made. In most cases ( o9 pei cent ) , the initial heading was followed for about one-half mile and then it was altered by erratic or zigzag flight, with a half mile or less being flown in each of a variety of directions. In a few instances, a par- William E. Southern HOMING IN HERRING GULLS 191 Fig. 1. Exemplary route of a radio-tracked Herring Gull released about 20 miles west of the colony. The colony is located on the peninsula east of Rogers City. Key to symbols: * rr release site; o = period of circling behavior; — > — direction of flight. ticular route was maintained for about two miles before a different heading was selected. The fluctuating flight patterns involved as few as four headings and as many as 14. Repetition of easterly or southerly courses was common during prolonged periods of zigzag flight. Such behavior was occasionally interrupted by one or more circles that varied in diameter from a few yards to over one-half mile. The flight path of a Herring Gull tracked from its release site 20 miles west of the colony is illustrated in Ligure 1. It is presented as a typical example of the type of information that was recorded for each homing flight. The circling and erratic patterns were often followed by periods of straight flight which lasted for perhaps several miles. Ten (45.4 per cent) of the 22 192 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Herring Gulls released between 10 and 30 miles west of the colony followed a course leading to some point on Lake Huron, usually Hammond Bay, which was located north of the colony and represented the nearest large body of water. Two of these gulls returned home promptly — in 40 and 50 minutes — from this point by routes over the water, but within one-half mile of the shoreline. The other eight birds spent extended periods of time on the water and occasionally made additional exploratory flights. These gulls required from 3 to 36 hours (average 17 hours) to return. A few individuals failed to return from this location and one gull, that was released 20 miles west of the colony, homed successfully without deviating its course toward Hammond Bay. It departed eastward, and pursued a fairly direct route to the colony after performing a few circles and zigzags. The entire flight required 50 minutes. Twelve of the 22 Herring Gulls released up to 30 miles west of the colony departed along north, west, northwest, or northeast routes. Seven of the 12 returned in periods ranging from 3 to 151 hours (average 52 hours). Two gulls pursued northward courses toward a large inland lake ( Black Lake ) near Onaway. Both birds landed and remained on the lake for significantly long periods. Their courses between Black Lake and home were not deter- mined, but one had a homing time of 85 hours, and the other 151 hours. In these instances, it seems that “incorrect” initial headings resulted in greatly increased average homing rates. Individuals released at more distant sites, up to 110 miles, performed similarly with respect to general flight behavior. Only one Herring Gull was tracked during its complete homing flight from a site 60 miles from home. This bird was released near Little Traverse Bay (Emmet Gounty ) on Lake Michigan and spent six hours on the water preening, bathing, and just sitting. Thereafter, it flew southeast, zigzagged, circled, and then resumed a southeast course. This route was altered later and the gull followed a fairly direct path eastward to the colony. The flight lasted approximately two hours. Each gull released at locations along the other Great Lakes, or large inland lakes, reacted positively to these features and usually landed on the water. One of these birds returned from Lake Superior (110 miles from home ) after I discontinued tracking operations following a three hour wait for its departure. It returned 21 hours later. A Herring Gull released 105 -miles north-northwest, hut inland from Lake Superior, followed an erratic course, changing directions 14 times in 12 minutes. Its flight path was not tracked for more than 20 minutes because roads were unavailable. This bird required 125 hours to return. Gulls that successfully homed from distant locations exhibited the behavior patterns discussed in this section, but such activities were not unique to William E. Southern HOMING IN HERRING GULLS 193 successful individuals. Gulls that proved to be unsuccessful also zigzagged, circled, and altered their flight in other ways. There were, however, a few differences in flight patterns of the two groups and these will be discussed after I have described the remaining two categories. Flight behavior of homing failures. — Six Herring Gulls failed to return from distances ranging up to only 30 miles from the colony. These indi- viduals were tracked for distances totaling 170 miles and contact was main- tained for about 45 hours. Only one of the six gulls departed on a south- easterly course. After circling and changing headings numerous times, it flew north-northeast to Hammond Bay. Its particular course headings were followed for various distances (e.g., 0.5, 1.0, 4.0, and 7.0 miles). One other gull from this group was tracked to Hammond Bay, but its original departure flight of 0.5 miles to the north was followed by turns to the east for 3 miles, north 10 miles, and finally northeast 4 miles to the Bay. It landed on the water, remained for a short time, and later flew parallel to the shoreline for about two miles toward the colony; however, it never returned. It seems unlikely that these two individuals would get this close to home and then be unable to find their way over the remaining distance. It is more likely that the gulls failed for other reasons, possibly because of a motivation loss (i.e., tendency change) which resulted from handling procedures during prepara- tion for release. It is also possible, although unlikely, that both transmitters ceased to function after I left the birds at the above mentioned location and, as a result, I was unable to record their return. The other homing failures in this distance category departed to the north, west, or northeast. One of these was tracked for 18 miles, to within seven miles of the colony, before contact was lost. The apparent failure of this bird to return might also be explained by one of the possibilities given previously, rather than by disorientation. The cause for loss of radio- contact was not determined. There were six homing failures from distances ranging from 40 to 110 miles. Each individual circled and zigzagged soon after departure from release sites and two headed in homeward directions. The six gulls were tracked for 227 miles and for periods totaling 38 hours. In general, their behavior was comparable to that of birds failing to return from shorter distances. Activities of delayed homers. — This discussion is not really distinct from the previous two topics. The behaviors described herein were also performed by members of the successful and unsuccessful groups. Answers to several of the questions that continually recur during homing experiments may result from a knowledge of the activities and whereabouts of the birds that required, or took, unusually long periods of time to return from trials. Radio-tracking procedures enabled me to determine some pre- 194 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 liminary answers to these questions even though I was unable to continually follow all gulls that were equipped with transmitters. Three factors usually contributed to slow homing rates and to periods of extended absence: ( 1 ) ex- tensive flights in non-homeward directions; (2) long periods spent in other than flight activity; and (3) hesitancy to enter the colony or increased wariness of the experimenter after return. Several individuals were tracked for significant distances, up to 100 miles, in other than homeward directions. These flights might represent attempts to search for the familiar area or landmarks associated therewith, or they may be indicative of disorientation. The types of circling and zigzag patterns described previously were often repeated during such flights. These behaviors resembled the theoretical search patterns described by Griffin ( 1955 ) . Searching, as recorded by radio-tracking, is not, however, as regular in pattern or as consistent in occurrence as those diagrammed by Griffin. It is interesting that many gulls eventually homed after flights of this nature; however, the factors associated with their eventual ability, or desire, to return were not determined. Radio-tracking data showed, at least in a few cases, that the eventual homeward flights were not direct, but usually involved zigzag patterns. At least nine radio-tracked Herring Gulls landed in fields or on lakes and remained there for fairly long periods. Several untracked individuals be- haved similarly. Occasionally these landings occurred immediately after release, particularly when gulls were freed near lakes or at night; but, on other occasions, the birds landed after traveling 15 or 20 miles. Recorded duration of such “rest periods” ranged from 15 minutes to 6 hours. It is possible that particular individuals remained even longer in one place since I usually discontinued tracking operations after the experimental subject remained at one location for three hours. “Rest sites” varied from lakes to open fields near release sites to similar areas located adjacent to the colony. Herring Gulls tracked along the south side of Lake Superior appeared attracted to flocks of local Herring Gulls whereas Herring Gulls released closer to home and Ring-hilled Gulls released at all sites failed to show comparable tendencies. Several Herring Gulls spent at least three hours with these local groups of Lake Superior Gulls. There was no indication that this social attraction had any influence on orientation success. Gulls known to associate with local flocks required from 24 to 125 hours to return from a site 110 miles away. The increased wariness of some individuals was mentioned earlier. Radio- tracking results showed that particular gulls spent several hours on the water or feeding near the colony prior to their actual return. Other birds returned, hut were extremely nervous and de])arted when the observers approached. William E. Southern HOMING IN HERRING GULLS 195 Awareness of this type of behavior creates some concern regarding the accuracy of figures denoting homing success of non-tracked subjects used in this study and others. Comparison between en route behaviors of successful and nonsuccess ful Herring, Gulls. — There were no obvious differences, of apparent significance, between en route flight behavior of successful and unsuccessful Herring Gulls. Both groups performed periodic circling and zigzag patterns which were interspersed with straight flights ranging up to 10 miles in length. A variety of temporary course headings (4 to 14) were followed by particular individuals of each group. Gulls released adjacent to large bodies of water usually landed. Birds that encountered lakes or open fields after departure from release sites also landed occasionally. A few behavioral variations were apparent. The primary difference existed in departure directions. Approximately 68 per cent of the successful Herring Gulls departed to the east, south, or southeast which often represented the homeward direction. In contrast, only 25 per cent of the Herring Gulls that failed to return selected one of these three directions. This might seem to suggest that departure directions are indicative of homing ability; however, observational data failed to support this possibility. The other apparent behavioral difference pertained to the relative amounts of zigzagging. Suc- cessful gulls zigzagged less during homing flights. Several directions were pursued for various distances by the successful birds but the routine was not repeated as often nor did they pursue the number of different headings re- corded for unsuccessful gulls. Several unsuccessful birds zigzagged for longer periods and performed this behavior in a much less regular fashion than did successful gulls. The homing failures sometimes changed course headings frequently, maintained new headings for shorter periods, and were likely to repeat these directions during the same zigzag sequence. The general impression was that of disorientation, or at least difficulty in selecting or maintaining a preferred course. RESPONSE TO TOPOGRAPHICAL FEATURES It is extremely difficult to evaluate accurately the role of landmarks in avian orientation. It appears almost impossible to determine by currently available techniques whether or not a bird is responding to specific topo- graphic features. It is equally difficult to measure the extent of what might he considered a positive response to landmarks under field conditions. Re- gardless of this, many authors have reported various effects of landmarks (e.g., mountains, large bodies of water, valleys, shorelines) on homing birds. Matthews (1951, 1953, 1955) thought such features were used in landmark orientation; Graue and Pratt (1959), Hitchcock (1952, 195d). 196 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Pratt and Thouless (1955), and Pratt and Wallraff (1958) believed they served as distracting factors; and others, Griffin (1952), Hitchcock (op.cit. ), Arnould-Taylor and Malewski (1955), and Kramer (1957), have credited such features with having a type of funneling effect on birds. Schmidt- Koenig (1965), however, has pointed out that a good deal of evidence speaks against the role of landmarks in each of these three apparent responses. He feels that landmarks are certainly involved in recognition of home areas. During this study it was occasionally possible to record the apparent re- actions of gulls to particular gross land features (e.g., large bodies of water). If an experimental bird altered its course in accordance with particular land- forms, this was considered as a positive response to that factor and that it is possibly involved in orientation. Although radio-tracking techniques enabled me to determine the approxi- mate route taken by homing birds, the method is not refined enough to accurately pinpoint a gull’s position with relation to particular land features. The usual degree of plotting error encountered during triangulation on a transmitter-bearing gull’s position would place the bird within a three- to six-acre area at a tracking range of about two miles. This error is further increased by the use of mobile units since the exact position of the vehicle cannot be determined. As tracking ranges decrease, as with landed birds or those meandering in one area for some time, tracking accuracy significantly increases. Even with maximum tracking efficiency, it is impossible to know the range of a bird’s vision and to even postulate on the location of potential clues within the range of vision. Because of these difficulties and others, it is obvious that no thorough evaluation of terrestrial clues has been conducted to date. Hochbaum’s (1955) outstanding interpretation of waterfowl behavior probably represents the most thorough attempt. Until we possess a better understanding of avian learning, memory, and responses to particular land features, I consider it impossible to disregard the potential for birds using such features in long and short distance orientation. In spite of these handicaps, it was possible to determine the reactions of radio-tracked Herring Gulls and color-marked Ring-billed Gulls to several types of gross land features. These were: (1) shorelines of the Great Lakes; |2) river valleys; (3) wooded moraines; and (4) roadways. More evidence was obtained regarding responses to shorelines since these features were most extensive and because it was easier to determine the bird’s course in relation to these features. A total of 69 gulls were released along the Great Lakes during the two years. Thirty-eight (55.1 per cent) returned successfully (Table 2). Seven of the Herrins Gulls were radio-tracked for a total of 390 miles. Without William E. Southern HOMING IN HERRING GULLS 197 Results (U' IAble 2 Homing Trials Associated With the < Great Lakes. Lake Number released Distance ( miles ) Success Failed Returned irer cent Time range ( hours ) Average Michigan 13 68 82 7 6 46.2 16-29 26.2 Straits of Mackinac 8 55-60 1 7 87.5 7-28 20.1 Huron 17 15-17 9 8 47.1 2-88 38.5 Superior 31 85-150 14 17 54.8 19-92 43.1 exception, gulls released near one of the lakes followed the shoreline. In every case where the shoreline approximated a north-south direction and release sites were over 20 miles from home, a majority (78 per cent) of the gulls departed northward along the shore, regardless of homeward direction. Over half (56.8 per cent) of these birds failed to return. Gulls released at two localities, Lake Michigan (near Gross Village, Emmet Gounty ) and Lake Superior (north shore near Montreal River, Ontario), were all unsuccessful. The activity of individuals released along the Lakes involved “resting” on the water but also periods of flight paralleling the shoreline. In many instances, these routes lead gulls farther from home. After I made several releases at particular sites, it was often possible to predict the outcome of the trials; i.e., most gulls departed northward along the shore and apparently required long periods to return or failed to return. Tracking records and observations of ring-bills suggested that they followed the shoreline in an attempt to locate familiar landmarks. The shoreline, although probably not visited previously by these individuals, resembled the home area and the typical situation a gull would normally frequent. The typical response to this situation was not suggestive of any ability to navigate or orientate by means of the sun or physical clues. The shoreline courses were followed for considerable distances in some cases and possibly until the desire to home was lost. It is also possible that these responses represent an attempt to select air cunents suitable for flight. Updrafts would probably be associated with the Great Lakes shorelines and some moraines, and rising warm air from paved highways might effect low level flights. Therefore, response to these features might be related to flight dynamics and not to homeward orientation. Two Herring Gulls released inland were tracked while they were apparently following the meandering course of the Ocqueoc River ( Presque Isle Gounty ) . Both birds followed the irregular non-homeward course of the river for about four miles. Thereafter, they headed on a more direct homeward course. 198 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 I he river may have provided the necessary clues for selection of the latter course. Only circumstantial evidence exists to support the speculation that Herring Gulls responded to moraines or highways. One individual was definitely observed to change its course to correspond with a north-south terminal moraine located about nine miles west of the colony. Ihe west side of the forested hill was followed south for two miles before the gull angled eastward toward home. Several individuals appeared to follow roads during periods of low flight. They flew straight courses over the highway at elevations of 100 to about 200 feet and for distances ranging up to nine miles. While it seems unlikely, that gulls could use individual roads as orientational clues outside of their familiar area, it is possible that the overall pattern of high- ways observable at high altitudes might influence flight direction during homing trials. Hochbaum (1955 ) referred to the use of various types of topographical features by waterfowl during flights within the familiar area. He also indicated the apparent use of similar clues during migration and showed that topographic configuration of the earth’s surface channels flight in some areas. Eurther supportive evidence for use of landmarks was pro- vided by Dorst (1963), Griffin (1952), (1955), Tinbergen (1949), and Wilkinson (1952). Griffin and Wilkinson have also demonstrated that these clues could be used in association with purely random search patterns. Skinner’s (1950) work has provided additional support to this possibility by showing that the visual perception of pigeons is highly developed and would permit use of such clues. Skinner also found that pigeons possess visual memory and are able to respond to specific visual stimuli four years after the initial tests. Hamilton ( 1962 ) , however, has suggested that these observations in themselves do not give evidence that features of the terrain establish the basic course of flight but only that passing birds respond to topography. In general, it appears that a strong case still exists for landmark orienta- tion by some species. However, so long as we must attempt to guess at what the bird might be seeing, recognizing, and responding to while en route, it will he impossible to adequately evaluate the role of topographical features in avian orientation. SUMMARY Forty-one Herring Gulls were radio-tracked during homing trials. Twenty-nine radio-tracked gulls returned successfully, 18 of which were tracked during essentially all of their flight. Initial flight hehaviors were classified as direct, delayed, and those in- volving “rest periods.” The flight patterns of successful, unsuccessful, and delayed homers are discussed. 'I'liree factors contrihuted to slow homing rates: (1) flights in non-homeward directions; William E. Soutliern HOMING IN HERRING GULLS 199 (2) long periods involving other than flight behavior; and (3) hesitancy to actually enter the colony upon return. Flight patterns of homing birds resembled the theoretical search patterns described in the literature. There were apparent responses in relation to particular topographical features, some of which could be predicted in advance by observers. Gulls followed shorelines of lakes, a river basin on one occasion, and a terminal moraine. Landmarks apparently influenced the direction of Herring Gull flight and may have played a role in orientation. LITERATURE CITED Arnould-Taylor, W. E. and A. N. AIalewski. 1955. The factor of topography in bird homing experiments. Ecology, 36:641-646. Dorst, J. 1%3. The migrations of birds. Houghton Mifflin, Boston. Grade, L. C. and ,I. G. Pratt. 1959. Directional differences in pigeon homing in Sacramento, California and Cedar Rapids, Iowa. Anim. Behav., 7:201-208. Griffin, D. R. 1943. Homing experiments with Herring Gulls and Common Terns. Bird-Banding, 14:7-33. Griffin, D. R. 1952. Airplane observations of homing pigeons. Bull. Mus. Comp. Zook, 107:411-440. Griffin, D. R. 1955. Bird navigation. In: Recent studies in avian biology, A. Wolfson [Ed.], Univ. Illinois Press, Urbana. Griffin, D. R. and R. .J. Hock. 1949. Airplane observations of homing birds. Ecology, 30:176-198. Hitchcock, H. B. 1952. Airplane observations of boming pigeons. Proc. Amer. Phil. Soc., 96:270-289. Hitchcock, H. B. 1955. Homing flights and orientation of pigeons. Auk, 72:355-373. Hamilton, W. J. 1962. Initial orientation and homing of inexperienced Pintails. Bird- Banding, 33:61-69. Hochbaum, H. a. 1955. Travels and traditions of waterfowl. Univ. Minnesota Press, Minneapolis. Kramer, G. 1957. Experiments on bird orientation and their interpretation. Ibis, 99: 196-227. Kramer, G. 1961. Long-distance orientation. In: Biology and comparative physiology of birds (A. J. Marshall, Ed.). Academic Press, New York. Matthews, G. V. T. 1951. The sensory basis of bird navigation. J. Inst. Navigation, 4:260-275. Matthews, G. V. T. 1952. An investigation of homing ability in two species of gulls. Ibis, 94:24.3-264. Matthews, G. V. T. 1953. Tbe orientation of pigeons as affected by the learning of landmarks and by the distance of displacement. Anim. Behav., 11:310-317. Matthews, G. V. T. 1955. Bird navigation. Cambridge Univ. Press, Cambridge. Pratt, J. C. and R. H. Thouless. 1955. Homing orientation in pigeons in relation to opportunity to observe tbe sun before release. .1. Exp. Biol., 32:140-157. Pratt, .1. G. and H. G. Wallraff. 1958. Zwei-Richtungs-Versuche mil Brieflauben. Langstreckenfliige auf der Nord-Siid-Achse in Westdeutscbland. Z. Tierpsycbok. 15:, 3.32- .339. Schmidt-Koenig, K. 1965. Current problems in bird orientation. In: Advances in the study of behavior ( D. S. Lehrman, R. A. Hindc, and E. Shaw. Eds.). Academic Press, New York, 200 THE WILSON BULLETIN June lyyo Vol. 82, No. 2 Skinneh, B. F. 1950. Are theories of learning necessary? Psychol. Rev., 57:193-216. SouTiiEHN, W. E. 1963. Equipment and techniques for using radio-telemetry in wild- life studies. Northern Illinois Univ. Report No. 3. Southern, W. E. 1967. The role of environmental factors in Ring-hilled and Herring Cull orientation. Unpuhl. Ph.D. Dissertation, Cornell Univ., Ithaca, New York. Tinbergen, N. 1949. Vogels onderweg. Vogeltrek over Nederland in samenhang mit landschap, weer and wird. Scheltema and Holkema, Amsterdam. Wilkinson, D. H. 1952. The random element in bird navigation. J. Exp. Biol., 29: 532-560. DEPARTMENT OF BIOLOGICAL SCIENCES, NORTHERN ILLINOIS UNIVERSITY, DEKALB, ILLINOIS 60115, 29 JANUARY 1968. NEW LILE MEMBER A recent addition to the roster of Life Memhers of the Wilson Ornithological Society is Dr. Richard C. Banks of Alexandria, Virginia. Dr. Banks, who holds degrees from The Ohio State University and the University of California, Berkeley, is currently Chief of the Bird Section. Bird and Mammal Lahoratories, Division of Wildlife Research, Bureau of Sport Fisheries and Wildlife. His ornithological interests are in the systematics of North American birds, hybridization, and the biology of introduced birds, and he has published about 60 papers on birds and mammals. He is currently the Secretary of the A.O.U. and is also a member of the Cooper Society, the American Society of Mammalogists, Society of Systematic Zoology, and the Biological Society of Washington. Dr. Banks is married and has two children. MOLT AND TAXONOMY OF KED-BREASTED NUTHATCHES Richard C. Banks Routine identification of a small series of Red-breasted Nuthatches (Sitia canadensis) at the U. S. National Museum necessitated a review of the recently proposed (Burleigh, 1960) division of that species into two subspecies, S. c. canadensis in eastern North America and S. c. darker ga in the west. Most authors who have dealt with the species recently have not used the trinomials and have not commented on the recognition of geographic variation in this species (e.g., Mengel, 1965; Johnson, 1965; Godfrey, 1966). However, Todd (1963:533 ) commented that the proposed form “does not appear to me to be sufficiently well characterized,” and Phillips, Marshall, and Monson (1964: 114) stated that “careful examination of recent fresh fall skins from Maine and Arizona fails to reveal racial differences. . . .” Bailey and Niedrach (1965:582) used the name clariterga without taxonomic comment. Despite the consensus that the race clariterga is not valid, it seemed advis- able to review the material on which its proposal was based. Burleigh ( 1960: 212) stated that S. c. clariterga differed from nominate canadensis hy having the “upperparts lighter and more hluish and lacking to a large extent the gray- ish wash characteristic of the nominate race.” In a preliminary examination of subspecifically identified material at the U. S. National Museum, the char- acteristics of the two groups of specimens as outlined hy Burleigh (1960) were plainly evident to me. However, I was disturbed hy the large number of east- ern specimens that had been designated as members of the western race, and vice versa; the proportion seemed too high even for such an erratic wanderer as the Red-hreasted Nuthatch. A more detailed study convinced me that the racial division should not be recognized. More importantly, I believe, reassess- ment of the evidence has made it possible to state rather precisely how it was misleading and why the name clariterga must be considered a synonym of canadensis. This could not have been accomplished without examination of the material used in the original study. The conclusions based on the study of the material in the U. S. National Museum were checked and verified hy ex- amination of the large series of Sitta canadensis at the American Museum of Natural History. MOLT AND AGE CHARACTERS To determine whether variation related to age might either mask or enhance any trends of geographic variation in color, I studied specimens in the com- plete late summer molt in an attempt to develop criteria for the separation of 201 202 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 age groups. Even though no such criteria were found, a brief discussion of this phase of the study is a necessary prelude to a consideration of the basic problem. Ageing. — The plumage of juvenile Red-breasted Nuthatches is extremely similar to that of adults. The similarity is enhanced by the structure of the feathers of adults, which, with their widely spaced barbs, have the soft appear- ance usually associated with juvenile birds of passerine species. The difference in structure between the adult and juvenal body feathers is most noticeable on the ventral surface, but since this area is among the first to undergo molt, the distinction is soon lost. Juvenile males have dull rather than shiny black caps, but this distinction also is soon lost because of the rapid progress of molt. Young females have a duller gray pileum than adults, without black feather edgings, but the presence of the latter is highly variable even in adults. Birds which are involved in the postnuptial or postjuvenal molts can be aged as first-year or adult by the fact that only adults molt the flight feathers. This distinction can be made through virtually the entire period of molt, since the inner primaries of adults are among the first feathers to be lost and the outer primaries are among the last to complete growth. In the final stages of molt, when the primaries of adults have all regrown, the relatively older remiges of the juveniles are more worn than those of adults, but I have been unable to use this feature consistently or with confidence to age specimens. I have not found any differences of shape or color between the juvenile and adult flight feathers or coverts which might be used to separate age groups, and there seems to be no way to distinguish adult birds from first-year birds after the assumption of the adult or first basic plumage. Molt in adiihs. — The complete postnuptial (prebasic) molt of adults may begin as early as the middle of June. Molt of the primaries begins slightly be- fore molt of the body feathers, but replacement of the latter proceeds rapidly and the change of plumage in the two areas is completed more or less simul- taneously. Molting adults in the collections studied were too few and variation too great to permit statements of precise correlation between primary and body feather molt, but most stages of primary molt were represented and a few gen- eralizations can be made. Eewer females than males were available and the comments presented here are based mainly on the males, but there seems to be no essential difference between the sexes either in timing or progress of the complete molt. At the time that the first or second primaries are in sheath there is no or very slight molt of the body feathers; at most a few new feathers may be com- ing in on the lower throat and upper breast. Even by the time that primary 6 is partly grown, the body molt may be restricted to a small area of the upper Kicliarcl C. lianks NUTHATCH MOLT AND TAXONOMY 203 or central breast, but usually by tbis time extensive feather replacement is oc- curring on the throat and breast, extending slightly down the flanks. Also at this stage molt is in progress on the upper back and on the anterior ])art of the crown. When primary 7 is in sheath, body molt has extended farther down the flanks and there are some new feathers on the upper and middle part of the hack. Most of the anterior crown is new, and there are many feathers in sheath on the posterior crown and on the forehead. Molt of the ventral sur- face, except the lower flanks, may be nearly completed by the time primary 9 is in sheath, before primary 10 is lost, but even when this outermost primary is missing there may be many sheaths on the lower throat. At the latter stages the back will contain a mixture of old and new feathers with some in sheaths, and the crown will have many sheaths posteriorly. In birds, marked adult by collectors, in which all primaries have been replaced, all the body feathers are also new. There is considerable variation between individuals in the timing of the an- nual molt. For example, birds with primary 5 in sheath were taken as early as 3 July and as late as 3 August. Individuals with primary 6 in sheath were taken on 24 June and 11 August. A bird with primary 9 in sheath was taken 27 August, whereas one with primary 10 in sheath was taken 27 July. These comparisons point up the fact that birds of a given date may he as much as 6 weeks, perhaps more, apart in plumage stage (or feather age). It is important to keep this in mind if one wishes to compare individuals or series in strictly comparable plumage. Molt in juveniles. — The postjuvenal (first prehasic) molt of the body feath- ers of young nuthatches begins more or less simultaneously in several areas of the body. Sheaths appear early on the central throat and the upper hreast, and at about the same time on the central crown and lower hack. On the ventral surface, the area of new feather growth expands to the lower throat and cen- tral breast, and includes the upper part of the flanks. During this stage re- placement of feathers dorsally expands to take in the entire crown. In a slightly later stage, when on the ventral surface many new feathers are show- ing through the old ones, molt is extensive on the throat and hreast, extending posteriorly to the central flanks. Also at this time it is extensive on the crown and hindneck, and there are some sheaths on the central back. Molt progresses rapidly from this stage, with the entire body soon showing more new feathers than old. There is no replacement of flight feathers in this molt. As in adults, there is a high degree of variability in the timing of the onset and completion of the molt. Birds in the very earliest stages of body molt have been taken as early as 12, 13, and 18 July, and as late as 16 September. Simi- larly, birds in the very latest stages of molt, or which have just completed the 204 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 molt, are available from 29 and 30 July, and from 22 and 24 September. Tbis again points out tbat similar plumage stages may be as much as two months apart chronologically. THE SUBSPECIFIC DISTINCTION Birds taken in the months of November and December were sorted geo- graphically, and eastern specimens were compared to western ones. Although the difference in color of the dorsal surface reported by Burleigh (1960) was evident, approximately 15 per cent of the birds fell into the “wrong” group when the birds were arranged by color and geography. The same situation held when birds from January and Lehruary were compared, or when samples from any relatively discrete time period were studied. As noted earlier, however, birds taken in a given time period may differ by as much as 2 months in the age of the plumage; that is, one bird may have a feather coat that has been subject to 2 months more wear than another bird taken at the same time. To avoid comparing birds of different plumage ages, I selected birds that had just completed, or were just completing, the annual molt. When eastern and western examples of similar molt stages, or of similar plumage ages, were compared, no differences in color could be noted. Thus it appears that the wear that can take place during a period of approximately 2 months was at least in part responsible for the color difference that had been attributed to geographic variation. Once the color variation in specimens of similar collection date was noted, it was reasonable, although erroneous, to ascribe it to geographic factors because of the additional factors discussed below. When I sorted birds taken in a particular month according to the suhspecific names canadensis and clariterga that had previously been put on the labels, several of the former seemed at first to fit better with the series of lighter, bluer birds called clariterga. In every instance, however, closer examination refuted the first impression. Several of my colleagues at the U. S. National Museum were asked to examine the series, and each of them picked some or all of the same birds from the darker group for more critical comparison with the lighter group. On close comparison, however, none of those selected quite fit into the series called clariterga-, all were too dark. It became evident that the birds selected were those in fresher, less worn plumage. Linally it was noted that the white superciliary stripes of these specimens showed consider- able sooting, a condition that was present hut not evident on other parts of the dorsal surface because of the general blue-gray color of the birds. More of the eastern birds were sooted, and thus darker, than western ones, presumably be- cause of the greater degree of industrialization in the eastern part of North Richard C. Banks NUTHATCH MOLT AND TAXONOMY 205 America, which is thus a second factor to he considered in the apparent geo- graphic variation. Another determinant of the appearance of a color difference between east- ern and western birds was the quality of the prepared skin. Not only were the supposed canadensis chosen for comparison with clariterga in fresh but sooted plumage, but they were also well prepared specimens, with the dorsal feathers very neatly arranged. It turned out that most of these selected eastern speci- mens had been collected by Burleigh. A result of the exceptional quality of Burleigh’s specimens was that they were not strictly comparable to the main body of material in the collection. Because of his extensive work in the west- ern portions of the United States there was a preponderance of better quality material from that part of the country in the U. S. National Museum for com- parison with relatively poorly prepared material from the east. SUMMARY The postnuptial and postjuvenal molts of Red-breasted Nuthatches occur from middle June to late Septemljer. Some birds may he nearly finished with the complete molt before other individuals begin, so that specimens taken at any given time may differ by as much as two months in the age of their plumage. No characters useful in ageing birds after the completion of the autumn molt were found. The proposed racial subdivision of Sitta canadensis was based on misleading evidence resulting from variation of plumage age in birds assumed to be seasonally comparable, sooting of birds in industrialized parts of the country, and variation in quality of prepared specimens. LITERATURE CITED Bailey, A. M., and R. J. Niedrach. 1965. Birds of Colorado. Denver Mus. Nat. Hist. Burleigh, T. D. 1960. Three new subspecies of birds from western North America. Auk, 77:210-215. Godfrey, W. E. 1966. The birds of Canada. Nat. Mus. Canada Bull. No. 203. Johnson, N. K. 1965. The breeding avifaunas of the Sheep and Spring ranges in south- ern Nevada. Condor, 67:9.3-124. Mengel, R. M. 1955. The birds of Kentucky. Ornithol. Monogr. No. 3, Amer. Ornithol. Union. Phillips, A., J. Marshall, and G. Monson. 1964. The birds of Arizona. Univ. Ariz. Press, Tucson. Todd, W. E. C. 1963. Birds of the Labrador Peninsula and adjacent areas. Univ. Toronto Press, Toronto. BUREAU OF SPORT FISHERIES AND WILDLIFE; U. S. NATIONAL MUSEUM, WASHING- TON, D. c. 20560. 31 OCTOBER 1968. A COMPARATIVE STUDY OF THE FOODS OF THE SORA AND VIRGINIA RAIL’ Gerald J. Horak Three species of rails nest regularly in the marshes of northern Iowa: Sora (Porzana Carolina), Virginia Rail (Rallus lirnicola) , and King Rails {Rallus elegans) . The former two are quite abundant in most years and usually frequent the same habitat. To compare their possible competi- tion for foods, a study was conducted during the summers of 1963 and 1964. Emphasis was placed on comparing food availability with its utilization by the two species of rails. Attempts to correlate food habits with food avail- ability have been reported by Glading, Biswell, and Smith (1940) in their study of California Quail, by Bellrose and Anderson (1940) on ducks, and by Hungerford (1957) on Ruffed Grouse. The present study attempts to show this relationship for the Sora and Virginia Rail. STUDY AREA Rails were collected from three areas in Iowa: Jemmerson Slough in Dickson County (Section 31, Spirit Lake Township); Goose Lake in Hamilton County (Section 27, Lyon Township); and Smith’s Slough in Clay County (Section 26, Lake Township). Most of the work was conducted on Smith’s Slough, a 287 acre marsh hounded by Trumbull Lake on the west, cultivated land on the north and south, and by county road H on the east. Water leaves this study area from the southwestern section by way of two narrow channels which lead into Trumbull Lake. The marsh is never more than 4 feet deep and most is less than 2 feet in depth. The dominant vegetation of the upland area surrounding Smith’s slough is Kentucky blue grass {Poa pratensis) . The wet-meadow and shallow marsh areas consist mainly of slough grass {Spartina pectinata) , sedge iCarex spp. ), and smartweed i Polygonum sp.) The major plants of the deep-marsh zone are narrow-leaved cattail (Typha angustifolia) and river bulrush (Scirpus fluviatilis) . Approximately 25 percent of the deep water part of the marsh was open water during the study. METHODS Analysis of food habits. — Rails were collected either by shooting or by driving them into traps. The gizzard and proventriculus were removed as soon as possible and preserved. The preserved organs were cut open and the contents were washed into a sieve con- structed of three strainers: a 44c)-inch wire mesh, a %2-inch wire mesh, and a linen cloth to catch the finer particles. If the gizzard contained grit, the sample was placed into a 250 ml beaker and carbon tetrachloride was added. After a few minutes, the grit sank to the bottom and the food material floated. Tlie food and grit were placed in individual Petri dishes and allowed to dry for several hours. The contents of the organs were then examined with a dissecting microscope. The sample was separated into major groups and an estimate was made of the numbers 1 Contribution from Federal Aid to Wildlife Restoration Investigations Project, Iowa, PR-W- I05-R, and Iowa State University, Deirarhnent of Zoology and Entomology. 206 Gerald J. Horak RAIL FOOD HABITS 207 of each type of food. Seeds were identified with the aid of Martin and Barkley (1960, and Isely and Braggonier (1962); and invertelnates with the aid of Eddy and Hodson (1958), Pennak (1953), and Usinger (1956). After all the gizzards were examined, the process was repeated and the contents were rechecked without reference to oirginal identifications. This time the sample was measured on a volumetric basis along with the enumeration. Each major group of foods was dried and placed in a graduated centrifuge tube which measured to the nearest Y^o ml. Particles smaller than Yn) ml were designated as a trace. McAtee (1912) strongly recommended the use of the volumetric method for analyzing food habits. He stated that frequency of occurrence and enumeration gave no indication of the size of food particles and, in most cases, overemphasized foods which were very resistant to digestion. The frequency of occurrence method is the quickest while enumera- tion is the most time consuming when small food items are present. During this study, all three major methods of analyzing gizzard contents were used to assure maximum accuracy. Measuring Food Availability. — Because rails feed mostly in shallow water areas, an attempt was made to measure both the flora and fauna of this habitat. A cylindrical bottom sampler with a diameter of 29 inches and height of 20 inches was made of sheet metal and covered an area of Ftooo of an acre. The sampler was placed randomly in an area known to he used regularly by rails. The lower edge of the cylinder was forced into the muck to prevent organisms from escaping and water from seeping in; then the muck and water were removed. This sample was then poured through a “tube separator” made out of three sections of stove pipe. Each section contained a screen with a different sized mesh: Yi inch at the top, % inch in the middle, and Yi6 inch at the bottom. These mesh sizes were chosen because they strained out the potential foods hut still allowed water and muck to flow through the tube. FOOD UTILIZATION Nineteen Soras and thirty-seven Virginia Rails were collected for study. Two Soras and two Virginia Rails were trapped in Jemmerson’s Slough and one Virginia and three Soras were from Goose Lake. The remaining birds were caught in Smith’s Slough. The rails were taken, for the most part, in shallow water of less than 24 inches deep in areas of dense stands of cattail or sedge. Table 1 shows, for each type of food found, the comparison in per cent, frequency of occurrence, enumeration, and volume. The findings show that seeds occur more often in the food of the Sora than in that of the Virginia Rail, while animal foods occur more often in the food of the Virginia Rail. However, Virginia Rails consumed a much larger amount of duckweed ( Lemna spp. ) . Grit was not included with the foods shown in Table 1 because the differences in the amounts consumed by the two species would bias the volumetric measurements. Therefore, grit was computed as a percentage of the total gizzard contents by the volumetric method. Soras contained an average of 23.2 per cent grit while Virginia Rails contained an average of 208 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 1 Food Habits of (19) Sora and (37) Virginia Rails Comparing Three Different Measurement Indices. Foods consumed Frequency of occurrence ( per cent) Enumeration ( per cent ) Volume ( per cent ) Sora Virginia Sora Virginia Sora Virginia Adult insects Coleoptera 31.5 35.1 0.4 3.7 T 2.4 Calliphoridae 5.2 0 0 0.5 0 Gryllidae 5.2 0 T 0 1.7 0 Hydrophilidae 15.6 40.5 0.2 3.7 0.5 13.7 Curculionidae 5.2 2.7 T 3.7 T T Dytiscidae 10.5 37.8 0.2 3.4 T 4.6 Diptera 0 2.7 0 0.2 0 0.2 Odonata 5.2 5.4 T 0.6 8.7 12.1 Notonectidae 0 2.7 0 0.2 0 T Nitidulidae 5.2 0 T 0 T 0 Unknown 10.5 10.8 — — 2.4 2.0 Insect larvae Hydrophilidae 15.6 32.8 0.2 5.3 T 2.0 Dytiscidae 0 16.2 0 1.5 0 T Diptera 21.0 43.2 0.3 15.9 T 22.0 Unknown 5.2 10.8 — — 0.8 1.5 Crayfish Decapoda 0 5.4 0 0.3 0 9.1 Unknown animal 15.6 40.5 — — 9.0 Snail Helisoma 10.5 18.9 0.2 3.0 1.2 3.9 Physa 5.2 0 0.7 0.3 T T Unknown 42.1 35.1 — — 1.3 2.1 Vegetation Polygonum 52.6 24.3 36.4 3.7 18.0 T Carex 79.0 35.1 27.8 9.2 21.5 1.7 Setaria 10.5 0 17.2 0 20.0 T Lemna 31.5 37.8 11.2 44.7 7.9 12.8 Scirpus 5.2 5.4 3.9 T 0.5 T Agropyron 0 10.8 0 1.1 0 T Unknown seeds 42.1 8.1 — — 12.9 0.9 * T = less than .1 per cent. 2.6 per cent grit. The high incidence of grit is characteristic of most seed- j eating birds ( Berger, 1961 ) . I All three of the techniques of measurements and analysis indicated that H there was a definite overlap in the kinds of food eaten by the two species of Gerald J. Korak RAIL FOOD HABITS 209 Table 2 Per cent ENUMEn.-VTioN of Potential Foods Found in 21 Bottom Samples. Potential Enunneration Potential Enumeration foods ( i>er cent ) foods ( per cent ) Vegetation (seeds) Snails Polygonum 24.5 Helisoma 1.1 Carex 11.5 Stagnicola 2.9 Scirpus 3.0 Physa 2.6 Potamogeton 0.3 Gyraulus 1.5 Typha Planorbula 2.9 Unknown 3.0 Fossoria T Insect adults Leeches Diptera 1.1 ErpobdeUa 2.6 Hydrophilidae 2.2 Helobdella 0.6 Hemiptera T Misc. invert. Dytiscidae 1.1 Hyalella 20.6 Coleoptera 1.0 CamboTus 0.6 Insect larvae Isoptera T Diptera 12.2 Hydrophilidae T Hemiptera T Coleoptera 1.5 * T = less than .1 per cent. rails, but Soras clearly ate a larger amount of plant material than did Virginia Rails. Pospichal and Marshall (1954) found that there was considerable over- lap of foods between the two species of rails. Martin, Zim, and Nelson (1951) stated that during the summer the Virginia Rails ate about 3 per cent plant material, while Soras ate 40 per cent plant material. None of these investi- gators related foods eaten to food available. FOOD AVAILABILITY IN IRELATION TO USE A total of twenty-one bottom samples was taken with the cylindrical sampler. The locations of the samples were chosen randomly near the trap sites. After a sample was taken and the muck and debris were removed, each potential food item was classified into taxonomic groups and enumerated (Table 2). Weights also were measured, but on a much broader classification than enumeration; for example, seeds, insects, snails, leeches and miscellaneous invertebrates. Table 3 compares percentage composition according to weights and enumeration. An index rating, based upon Bellrose and Anderson’s (1940) method, was used to relate the food-habits of the Sora and Virginia Rails to food availability. Bellrose and Anderson (1940) designated the food habits as 210 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Comparison of Per Potential Foods Table 3 CENT Weight and Enumeration of FOUND IN 21 Bottom Samples. Potential foods Weight (per cent) Enumeration (per cent) Seeds 20.7 42.3 Insects 35.5 20.1 Snails 26.1 11.0 Leeches 13.4 3.2 Misc. Invert. 4.1 21.6 the percentage of foods utilized by the birds, and this was measured by the volumetric method. Lood availability or percentage of abundance was based upon acres of various vegetative communities. In the present study, the percentage of foods used by the rails was based on the enumeration of the bottom samples. It was assumed that all foods present were equally available to feeding birds. Table 4 presents the data on bottom sample contents, per cent used, per cent abundance and utilization index rating of the Sora and Virginia Rails. A rating of 1.0 indicates that the food material was used approximately in proportion to its abundance. A rating of more than 1.0 indicates that the food was preferred by rails and a rating of less than 1.0 would indicate that food was less utilized than its abundance would imply. The index rating showed that the Soras preferred three seed types: Polygonum, Carex, Scirpus, and one insect, hydrophilid larva. The index rating also showed that the Virginia Rails preferred no seeds but selected six insect types: Diptera larva, adult and larval Hydrophilidae, adult Coleoptera, adult dytiscids, Ilemiptera adult and one snail, Helisoma. Table 4 indicated that 28.4 per cent of Sora foods and 46.6 per cent of the foods of the Virginia Rail were not found in the bottom samples. How- ever, of these foods, Lemna was found 11.2 per cent of the time by enumeration in the Sora and 44.7 per cent in the Virginia Rail. An exact count of each individual duckweed plant was not recorded in the bottom samples, and thus, a utilization index could not be calculated. However, the per cent of surface area covered in each bottom sample by the species was approximated and it was found that all the samples contained from 50 to 100 per cent J.emna. Of the 28.4 per cent of Sora foods not recorded in bottom sample, 17.2 per cent of this was foxtail. Loxtail appeared in only two of the rails. The foxtail group is predominantly a wet-meadow plant, a fact which would account for its not being collected in the bottom samples and also would indi- cate that the Sora may venture out of the marsh to feed. During the night Gerald J. liorak RAIL FOOD HABITS 211 Table T Index to Food Utilization by SOKA AND ViiiGiNiA Rails, 1963 AND 1964. Organism found in bottom sample Per cent used ( enumeration ) Per cent abundance ( enumeration ) Index rating Sora Virginia Sora Virginia Seeds Polygonum 36.4 3.7 24.5 1.6 0.1 Car ex 27.8 9.2 11.5 2.4 0.8 Scirpus 3.9 0.0 3.0 1.3 0.0 Potamogeton 0.0 0.0 0.3 0.0 0.0 T ypha 0.0 0.0 0.1 0.0 0.0 Najas 0.0 0.0 0.1 0.0 0.0 Insects Diptera larva 0.3 15.9 12.2 0.2 1.3 Diptera adult 0.0 0.2 1.1 0.0 0.2 Hydropliilidae adult 0.2 3.7 2.2 0.1 1.7 Hydrophilidae larva 0.2 5.3 0.2 1.0 2.6 Heniiptera adult 0.0 0.2 0.2 0.0 1.0 Hemiptera larva 0.0 0.0 1.3 0.0 0.0 Coleoptera adult 0.4 3.7 2.0 0.2 1.8 Dytiscidae adult 0.2 3.5 1.1 0.2 1.7 Snails Helisoma 0.2 3.0 1.1 0.2 2.7 Stagnicola 0.0 0.0 2.9 0.0 0.0 Physa 0.6 0.3 2.6 0.2 0.1 Gyraitlis 0.0 0.0 1.5 0.0 0.0 Planorbula 0.0 0.0 2.9 0.0 0.0 Leeches Erpobdella 0.0 0.0 2.7 0.0 0.0 Helobdella 0.0 0.0 0.6 0.0 0.0 Misc. Invert. HyaloUa 0.0 0.0 20.6 0.0 0.0 Camborus 0.0 0.0 0.6 0.0 0.0 Isoptera 0.0 0.0 0.1 0.0 0.0 Foods not found in bottom sample Agropyron 0.0 1.1 Setaria 17.2 0.0 Notonectidae 0.0 0.2 Odonata 0.0 0.6 Lemna 11.2 44.7 of 15 August 1963, a Sora was seen in a cultivated field approximately three miles from any marsh habitat. In the Virginia Rails, 1.1 per cent of the total food not recorded in the bottom sample was quackgrass, another wet-meadow plant, which also indi- 212 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 cates that Virginia Rails may feed in the uplands. The remaining 4.8 per cent of the Virginia Rails food not recorded in the bottom sample consisted of insects. DISCUSSION Cause’s (1943) principle states that two species with identical ecological requirements cannot live in the same niche. If two species of birds live in the same habitat in the same region, eat the same types of food, and have the same ecological requirements, there will be direct competition between the two species, and one may be eliminated. Grinnell (1904) said that two species can live together only by adaptation to different sorts of foods or modes of food getting. Lack (1944), in his survey of the ecology of passerine birds of Galapagos Islands, showed that similar species occurring together in the same habitat tended to differ from each other in feeding habits and associated morphology of the beak. The two species of rails observed in this study had some similarities but also major differences in their diets. The Sora, having a heavy short beak, eats approximately 73 per cent seeds, volumetrically. The Virginia Rail, with its long slender decurved beak, eats nearly 62 per cent insects, volu- metrically. These differences in food habits between the two species of rails suggest that the two species can live together successfully without serious competition for food. ACKNOWLEDGMENTS I extend my appreciation to Milton W. Weller, Leigh H. Fredrickson, David Strohmeyer, and Gerald Kaufmann for their assistance during the project. Milton W. Weller made helpful suggestions on the manuscript. LITERATURE CITED Bellrose, F. C. and H. G. Anderson. 1943. Preferential rating of duck food plants. Illinois Nat. Hist. Surv. Bull., 22:417-433. Berger, A. J. 1961. Bird study. John Wiley and Sons, Inc., New York. Eddy, S. and A. C. Hodson. 1958. Taxonomic keys to the common animals of the North Central states. Burgess Publishing Company. Minneapolis, Minnesota. Cause, G. F. 1943. The struggle for existence. Williams and Wilkins, Baltimore, Mary- land. Glading, B., H. H. Biswell, and C. F. Smith. 1940. Studies on the food of the Cali- fornia quail in 1937. J. Wildl. Mgmt., 4:128-144. Grinnell, J. 1904. The origin and distribution of the Chestnut-hacked Chickadee. Auk, 21:364-382. Hungerford, K. E. 1957. Evaluating Ruffed Grouse foods for habitat improvement. N. Amer. Wildl. Conf. Trans., 22:380-395. IsLEY, D. AND W. H. Braggonier. 1%2. Seeds of Iowa noxious and common weeds. Iowa State IJniv.. Agr. Ext. Serv. P-131. Gerald J. Horak RAIL FOOD HABITS 213 Lack, D. 1944. Ecological aspects of species formation in passerine birds. Ibis, 86; 260-286. Martin, A. C. and W. D. Barkleac 1961. Seed identification manual. Univ. of Cali- fornia Press, Berkeley and Los Angeles, California. Martin, A. C., H. S. Zim, and A. L. Nelson. 1951. American wildlife and plants. McGraw-Hill Book Co., Inc., New York. McAtee, W. L. 1912. Methods of estimating the contents of bird stomachs. Auk, 29: 449-464. Pennak, R. W. 1953. Fresh-water invertebrates of the United States. The Ronald Press Company, New York. Pospichal, L. B. and W. H. Marshall. 1954. A field study of Sora Rail and Virginia Rail in central Minnesota. Flicker, 26:2-32. UsiNGER, R. L. 1956. Aquatic insects of California. Univ. of California Press, Berkeley and Los Angeles, California. KANSAS FORESTRY, FISH AND GAME COMMISSION, COTTONWOOD FALLS, KANSAS, 8 AUGUST 1968. A NEW TURKEY EROM THE PLIOCENE OF NEBRASKA Larry D. Martin and James Tate, Jr. A study of avian fossil material from the Upper Pliocene of Nebraska has revealed the presence of a new genus and species of turkey ( Meleagrididae) . The type specimen and the referred material are deposited in the University of Nebraska State Museum Collections (UNSM). This material, including two left coracoids (UNSM 20033, complete and 20034, humeral Vi), two $ tarsometatarsi (UNSM 20037, lacking trochlea and 20035, proximal %), and a spur core (UNSM 20036), was collected from the lower part of the Kimball Formation, UNSM Coll. Loc. Ft-40, south of Lime Creek in Frontier County, Nebraska. The Kimball Formation is the upper formation of the Ogallala Group and is older than the San Pedro Formation of Arizona and the Rexroad Formation of Kansas, in which Agriocharis progenes Brodkorb occurs. A discussion of the stratigraphy of the Ogallala Group is outlined by Schultz and Stout (1961:7,9, Fig. 3). Vertebrate faunal lists for the Kimball Formation have been published by Schultz and Stout (1948:557, Table 1), modified by Kent (1963:14, Table 1) and include: Megalonyx; Hypolagus; Perognathus; Thornomys; Dipoides stirtoni Wilson; Dipoides williamsi Stirton; saber-toothed tiger (undet. ); Amebelodon. fricki Barbour; Teleoceras-, Neohipparion; Pliohippus [Astro- hippus) ; Pliohippus [Dinohippus] ; Nannipus; Prosthenops; Procamelus-, Pliauchenia; Cranioceras; Texoceros guymonensis Frick; Sphenophalos middleswarti Barbour and Schultz; Citellus kimballensis Kent; and Aphelops kimballensis Tanner. Proagriocharis gen. nov. Type speeies. — Proagriocharis kimballensis Martin and Tate Diagnosis. — Agrees with the Meleagrididae in having the median surface of the head on the eoracoid flattened (also flattened in the Gracidae, but it is notched in the Tetraonidae and Phasianidae) ; hraehial tuberosity lacking overhang (present in Tetraonidae and Phasianidae), and the scapular facet concave. Tarsometatarsus long and slender as in female turkeys and some Phasianidae (relatively short and stout in the Cracidae and Tetraonidae); inner calcaneal ridge long as in most Meleagrididae, most Tetraonidae, and most Phasianidae (ridge short in Craeidae, Gallus and other Galliformes ) . Proagriocharis differs from other genera of turkeys in having the follow- ing combination of characters: Coracoid resembling Parapavo and differing from Meleagris and Agriocharis in that the scapular facet is nearly rounded rather than elongate; the procoracoid is blunted, and the shape of the head is oval with indistinct mid-ventral noteh. It resembles Agriocharis and differs 214 Martin and Tate NEW PLIOCENE TURKEY 215 Fig. 1. A. Holotype of Proagriocharis kimballensis (UNSM 20033), left coracoid. B. Referred right tarsometatarsus (UNSM 20037), anterior view. C. Referred left partial tarsometatarsus (UNSM 20035), posterior view. D. Referred left spur core (UNSM 20036). E. Drawing of cast of right male tarsometatarsus, anterior view (see text ) . F. Cross section of right tarsometatarsus and spur core showing angle at which spur stands with the frontal plane of the bone. from Parapavo and Meleagris in that the head is raised above the inner surface of the neck. Proagriocharis differs from the other genera of turkeys in the shape of the coraco-humeral ligamental attachment which is elongate and lacks a distinct border on the outer side of the neck (triangular and having a distinct border on the outer side of the bone in the other Meleagrididae (Howard, 1927:6) ) . It also differs from the other three genera in that the pneumatic fossa is smaller and the triosseal canal is deeper so that the inner surface of the neck just below the head is reduced, producing a much thinner neck. The head is free from the neck for a greater distance than in any other turkey. The tarsometatarsus resembles Agriocharis and differs from Parapavo and Meleagris in the angle of the spur core to the acrotarsal surface (less than 60°; greater for Parapavo and Meleagris, less for Agrioeharis) . The spur core (cast) is more proximally placed (42 per cent of the total length) than it is in Agriocharis ocellata (36 per cent of the total length), and just overlaps the lower range of Parapavo and Meleagris in this respect. Proagriocharis kiml>alleii8i8 sp. nov. Holotype. — Left coracoid (Fig. lA), UNSM 20033 from UNSM Coll. Loc. Ft-40, south of Lime Creek, E V2, E V2, SW 14, Sec. 15, T5N, R26W, Frontier County, Nebraska. The stratigraphic occurrence is Pliocene, Ogallala Group, Kimball Formation. 216 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Table 1 Measurements in Millimeters of Two Bones from Proagriocharis KIMB ALLEN SIS MaRTIN AND TatE, AND AGRIOCHARIS PROGENES BrODKORB. A. progenes Measurement P. kimballemis (Brodkorb, 1964) Coracoid UNSM 20033 Total length 66 — Length to pneumatic foramen 58 65 Head through scapular facet 23 31 Width of head 9 10.8 Least width of shaft 6 10.1 Tarsometatarsus UNSM 20037 2 Width proximal end 13 — Length to top distal foramen 69 — Referred material. — The humeral end of a left coracoid, UNSM 20034. A right tarsometatarsus lacking the trochlea, UNSM 20037 (Lig. IB). The proximal end and greater part of the shaft of the left tarsometatarsus UNSM 20035 (Lig. 1C j and an isolated left spur core UNSM 20036 (Lig. ID). All of this material is from the same locality and horizon as the holotype. In the collections of the University of Nebraska State Museum there is also a cast (UNSM 20038) of an almost complete right male tarsometatarsus here referred to Proagriocharis kimballensh, from the type locality (Lig. IE). The original was in the private collection of Alex Keith (now deceased), who owned the property on which UNSM Coll. Loc. Lt-40 is situated. The where- abouts of the original specimen is presently unknown. Diagnosis. — Coracoid very small; flexure of the humeral end 63° to the axis of the shaft. Outer posterior intermuscular line curving away from the outer border of the shaft more than in Parapavo, Meleagris, or Agriocharis ocellata cutting across the dorsal surface of the shaft just above the midpoint. The inner posterior intermuscular line curving in from the inner border of the shaft more than in the other turkeys. The intermuscular lines similar in general form to those found in some of the Tetraonidae (i.e., Tympanuchus cupido) . The sterno-coracoidal process less developed than in Parapavo, Meleagris, or Agrioeharis ocellata extending only slightly beyond the sternal facet. Tarsometatarsus represented by two mature female specimens, and a spur core. The spur core long and well shaped as in Agriocharis. Tarsometatarsus thin, tapering distally. An incipient third ridge between the inner and outer ridges of the hypotarsus; the facet for the first toe (hallux) high and pos- Martin and Tate NEW PLIOCENE TURKEY 217 teriorly situated; the inner distal foramen a small depression. The cast shows a small, penetrating inner distal foramen. The following measurements are taken from the cast and therefore prob- ably differ slightly from the original: total length 9o mm, length to top of the distal foramen 84 mm, width of the proximal end 14 mm, height of middle of spur core 40 mm above tip of middle trochlea, angle of spur core to the acrotarsial surface 38° (Fig. IF). DISCUSSION Proagriocharis kimhallensis appears to be the oldest and smallest species of turkey described to date. Agriocharis crassipes from the Late Pleistocene of Mexico also has a small coracoid, but it is stouter and the tarsometatarsus of A. crassipes is larger as well as being more heavily built. The spur core is set at about the same angle (39°) as it is in Proagriocharis kimballensis and is only slightly more proximal in position (45 per cent of the length of the shaft). In these features Agriocharis crassipes is closer to the new genus than it is to any of the other described species of Agrioeharis. Proagrioeharis was a turkey about the size of a Sage Grouse (Centroeereus urophasianus ) with slim feet and a slender spur core. Miller (1940:156), described Agrio- charis crassipes as “. . . a bird with small body and wings, but with tre- mendously heavy feet, armed with an unusually stout spur.” Agrioeharis leopoldi (Miller and Bowman) and A. progenes Brodkorb are the two turkeys closest in time to Proagriocharis as both are Blancan in age (regarded as Early Pleistocene in this paper (see Flint, 1965)). Proagriocharis may be a suitable ancestor for both species, but they are not presently included in the new genus because of the difference in the placement of the spur core in these species. Agriocharis leopoldi has the spur core at a much greater angle (53-58.5°) and placed slightly lower (39.8 per cent of the total length) than it is in Proagriocharis (see Miller and Bowman, 1956:44). Agriocharis progenes has the angle of the spur core slightly less (50°) and the core slightly more distally plaeed than in A. leopoldi. A. progenes lacks the pneumatic fossa on the dorsal base of the shaft of the scapula (Brodkorb, 1964:226), and this might be expected to be absent from the scapula of Proagriocharis also. Both Agriocharis leopoldi and A. progenes are much larger than Proagrioeharis kimballensis. Although the coracoid has several features in common with Parapavo. Proagriocharis seems to have its greatest overall resemblance to Agriocharis. Despite their separation in time there is a great similarity in size between A. crassipes and Proagrioeharis. This is probably due to a secondary de- velopment of small body size in Agriocharis crassipes by the late Pleistocene. A. crassipes differs from Proagriocharis in the proportions of the limb bones 218 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 which are much heavier in the former. The evolution of the turkeys during the Pleistocene was apparently explosive. Three genera and eight species { Agriocharis leopoldi, A. progenes, A. anza, A. crassipes, A. ocellala, Mele- agris aha, Meleagris gallopavo, and Parapavo calijornicus ) are prohahly all sound species, most of which appear to have developed during the Pleistocene. Modern turkeys represent a depauperate group hy contrast, with only two surviving species. ACKNOWLEDGMENTS We are indebted to Pierce Brodkorb and C. Bertrand Schultz for critically reading this manuscript and offering many valuable suggestions. Dwight Brennfoerder prepared the illustrations. LITERATURE CITED Brodkorb, P. 1964. Notes on fossil turkeys. Quart. J. Florida Acad. Sci., 27 :223-229. Flint, R. F. 1965. The Pliocene-Pleistocene Boundary, Geol. Soc. Amer., Special Paper, No. 84, Intern. Studies on the Quaternary, p. 497-533. Howard, H. 1927. A review of the fossil bird Parapavo californicus (Miller), from the Pleistocene asphalt beds of Rancho La Brea. Univ. California Puhl. Bull. Dept. Geol. Sci., 17:1-56. Kent, C. 1963. A late Pliocene Faunal assemblage from Cheyenne County, Nebraska. Unpubl. M.S. thesis, Univ. of Nebraska, Lincoln, Nebraska. Miller, A. H. and R. I. Bowman. 1956. Fossil birds from the late Pliocene of Cita Canyon, Texas. Wilson Bull., 68:38-46. Miller, L. 1940. A new Pleistocene turkey from Mexico. Condor, 42:154-156. Schultz, C. B. and T. M. Stout. 1948. Pleistocene mammals and terraces in the Great Plains. Bull. Geol. .Soc. Amer., 59:553-588. Schultz, C. B. and T. M. Stout. 1961. Field conference on the Tertiary and Pleistocene of western Nebraska. Univ. Nebraska State Mus. Special Puhl.. no. 2. STATE MUSEUM AND DEPARTMENT OF ZOOLOGY, UNIVERSITY OF NEBRASKA, LINCOLN, NEBRASKA. (PRESENT ADDRESS: (J.T.) LABORATORY OF ORNI- THOLOGY, CORNELL UNIVERSITY, ITHACA, NEW YORK), 17 JUNE 1968. GENERAL NOTES Conjoined twin Darwin’s Rhea. — On 20 March 1969, a Darwin’s Rhea ( Pterocnemia pennata) egg was opened at the New York Zoological Park and was found to contain conjoined twin embryos. The egg was laid on 30 January 1969 and six days later, was placed in a forced-air incubator. By 17 March, movement was heard within the shell. Movement continued until noon on 19 March, when no signs of life could be detected. Other Darwin’s Rhea eggs incubated under the same conditions (97° F and 85 per cent relative humidity) had an average incubation period of 37 to 39 days. After 43 days of incubation, this egg was opened and the conjoined twins discovered. I 220 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 The embryos are joined and single ventrally from the lower mandible, to the sternum, and yolk sac. Dorsally the embryos are double with two sets of vertebrae, two sets of limbs, and basically, two separate bodies. Two separate upper mandibles fused at their base into one head with only one pair of eyes. At the back of the skull, two sets of vertebrae meet. The cranium was incomplete and 2.5 cm" of the brain was exposed, (see Fig. 1.) The twin embryo weighed 364 g while the yolk and yolk sac weighed approximately 100 g for a total of 464 g. Thirty-five normal newly hatched chicks averaged 426 g but varied from a low of 327 g to a high of 491 g. The eggshell itself weighed 84 g and varied from 0.040 to 0.042 inch in thickness. All of the waste material and the membranes from around the embryos totaled 65 g. The egg had lost 55 g or 8.2 per cent of its weight during development. An 8.2 per cent weight loss is 0.8 per cent above the average weight loss found in 30 Darwin’s Rhea eggs, at the New York Zoological Park, but is well below the maximum of 8.8 per cent that occurred in one other Darwin’s Rhea egg which hatched successfully. The specimen is preserved in a buffered formalin solution. I thank W. G. Conway for comments upon the manuscript. — Donald Bruning, New York Zoological Society, Bronx Park, Bronx, New York 10460, 8 May 1969. A swimming Bald Eagle. — During my 14-year residence in Alaska I have many times observed Bald Eagles (Haliaeetus leucoceplialus) plucking floating food from the surface of the water, and have heard reports of them entering the water in pursuit of live fish or ducks. Such incidents may be common, hut there are few descriptions in the literature. Bent (Life histories of North American birds of prey. Part I. Dover Publications, Inc., New York, 1961.) referred to several instances, but none of thein involved an eagle actually swimming. On the morning of 10 March 1969, at the oceanside laboratory of the U. S. Bureau of Commercial Fisheries at Auke Bay, Alaska, I witnessed an incident which demonstrated that an eagle can land on the water and regain its normal aerial environment afier “swimming” to shore wth captured prey. The incident involved a mature Bald Eagle and its prey, probably a female Barrow’s Goldeneye ( Bucephala islandica) . The duck was one of about a dozen in calm water about 25 yards from shore. The eagle was perched in the top of a tall spruce tree at the water’s edge, from which it launched itself on a steep glide toward the ducks. The ducks recognized their danger and attempted to escape by flying or diving. The eagle plunged into the water, intercepting one of the ducks that had already dived below the water surface. The eagle then calmly folded its wings and floated on the surface for about 2 minutes before attempting to reach shore. The duck was presumably being drowned during this wait and probably provided some houyancy to the eagle. Finally, the floating eagle propelled itself toward shore by slow rhythmic heats of its outstretched wings, much like a human swimmer using the butterfly breast stroke. It rode high in the water, so that on the forward motion of each stroke, both wings were simultaneously lifted almost clear of the water surface. The eagle reached shore, with the dead duck clutched in its talons. After resting for about 30 seconds, the eagle flew across the water carrying the duck, without having relaxed or changed its grip. — Theo- dore R. Merrell, .Jr., Bureau oj Commercial Fisheries Biological Laboratory, Auke Bay, Ahwka 99821, 26 May 1969. June 1970 Vol. 82, No. 2 GENERAL NOTES 221 Sharp-tailed Grouse gives aggressive display to automobiles. — Recently, while driving with my family on a busy four-lane divided highway I noticed a Sharp-tailed Grouse iPedioecetes phcisianellus) on the grassed dividing strip run briefly towards us with its head lowered and neck outstretched in an aggressive manner. All this happened in a matter of seconds, but it left a vivid impression because it seemed so improbable. Accordingly, as soon as we found a place to turn around, we drove back along the opposite side of the highway until we could see the grouse. We then drove slowly along on the shoulder of the road and parked about 50 feet from the grouse, which seemed to pay no attention to us. It was, however, still busily chasing passing cars. This was at 16:30 on 27 April 1969, on the Perimeter Highway close to Highway No. 59, southeast of Winnipeg, Manitoba. It was a bright day and we had an excellent view of the bird for the sun was behind us. The grouse was making a pass at each approaching car, first turning to face it, then, when the car reached a certain distance, running towards it and suddenly veering as the car passed. Sometimes it ran briefly alongside the car before turning back, but in any case it usually ran in a curved path. It seemed to be threatening each approaching car then driving it off, so to speak, and the results presumably satisfied it for as each challenged car pulled away the grouse ceased to pursue it and either turned to the next car or stood still. Inasmuch as vehicles, both cars and trucks, were moving by in good numbers the grouse was kept fairly busy. In one five-minute period it made passes at 15 assorted vehicles that drove by at various speeds on both sides of the center strip. These dashes towards approaching cars varied in length from a few feet to about 20 feet and depended upon the position of the bird in respect to the car when the bird first began to make its run. When a car approached after a lapse in traffic the grouse was in a position to make a run of some length, but when cars were passing in rapid succession it sometimes lunged at first one car and then another with hardly a pause. All this while it kept within an interval of about 40 or 50 feet, shifting back and forth as traffic varied in either direction. It thus occupied a territory about 50 feet in length and 20 feet wide, the latter being the width of the grassed divider. It also, and this seemed reason- able, kept back about six inches from the edge of the curb on both sides. During the 45 minutes that we watched this performance the grouse stopped chasing vehicles only twice. Its behavior then suggested that it had tired and was resting and indeed on one occasion it was lying down. Its rest periods were brief and in each case passing cars seemed to stimulate it to resume its peculiar game. On three or four occasions during traffic lulls it stood with wings held out sideways, head lowered, tail cocked, and then gave a few soft hoots — part of the typical display of a Sharp-tailed Grouse on its dancing ground. It also gave a few “chuckling” notes during these displays. I watched it closely with binoculars at these times and did not notice that it inflated its air sacs, but the display was clearly at a relatively low level. The eye-comb was pale yellow and ap- peared to be limited to a short strip anterior to the eye, rather than extending over the eye as expected. Presumably this was a subadult bird or one just coming into breeding condition. Several times it paused briefly to feed. Later, upon inspecting tbe site I found a sparse strip of oats growing in the grass down the center of the area. The strip had been mowed at some time during the previous year and oat heads were scattered about on the ground. It seems reasonable to suppose that the grouse had been attracted by this source of food and had then responded aggressively to passing cars. 222 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Evidence that the oats continued to prove attractive to grouse in the vicinity was obtained on 28 June when a female Sharp-tailed Grouse with oat kernels in its crop was found dead on the highway and close to the center strip in the same place that the male had occupied. The reactions of Ruffed Grouse iBonasa umbellus) to automobiles with running motors has attracted some attention (Bump et al, The Ruffed Grouse. New York State Cons. Dept., 1947, pp. 262-264) the sound of the motor being assumed to have some relation to the sound of grouse drumming, but I know of no similar reports for Sharp- tailed Grouse. Our period of observation ended abruptly at 17:15 when a car stopped about 300 yards away on an adjacent roadway about 50 yards south of the highway and a man got out to walk a dog. The grouse at once flew off strongly to the southwest for almost a mile before we lost sight of it. On the following day and on several days thereafter a number of observers visited the area, hut the grouse was not seen again on the center strip. At least three grouse were seen, however, on the access road to the south. When first sighted in the morning of 28 April these were displaying as if on a dancing ground. It is presumed that the bird that had chased the automobiles was one of these or at least a member of a group that was meeting close to the highway. — Robert W. Nero, Manitoba Museum oj Man and Nature, 190 Rupert Avenue, Winnipeg, Manitoba, 16 June 1969. Ring-billed Gull and Laughing Gull catch fish hy “skim- ming.”— On 27 April 1969 I was watching two Ring-hilled Gulls (Larus delawarensis) catching fish (probably Fundulus sp.) along the edge of rising tide waters in a small estuary (Gulf Pond) in Milford, Connecticut. Both birds were feeding hy the method called “ploughing” hy Zusi (Wilson Bull., 80:491-492, 1968) in his report of observations of Greater Yellowlegs ( Totanus melanoleucus) . In ploughing the l)ird runs through shallow water with the lower mandible cutting the surface of the water, seizing any prey contacted. On 9 September and 21 September 1969 in the same locality I saw ploughing hy small (6-9) groups of Laughing Gulls (Lams atricilla) , accompanied on the 21st hy similar numbers of Ring-bills. Again these birds were catching small fish near the water’s edge. On several occasions a bout of ploughing appeared to have been stimulated hy a Greater Yellowlegs ploughing the margin, with gulls then flying in from mudflats 20-40 meters away. One of the Ring-hills on 27 April was also seen capturing a fish hy “skimming.” This individual had been flying back and forth along the water’s edge at a height of about 10 feet. It turned and dived suddenly, almost to the surface of the water. For a period of 2-4 seconds it skimmed over the surface, with the lower mandible cutting the water (exactly like a Black Skimmer (Rhynchops nigra). While still in flight, the gull caught a small fish; it landed immediately and swallowed the fish. I saw this gull apparently skimming several times, hut only once could I he sure that the prey was captured while the bird was in flight. On 9 and 21 September an approach to skimming was seen in Laughing Gulls, resembling the skimming described above, except that the birds made hopping or paddling motions with their feet touching the water; during each flight the lower mandible remained constantly immersed. June 1970 Vol. 82, No. 2 GENERAL NOTES 223 On a number of occasions I have seen Ring-bills ploughing, but I know of no previous observation of feeding by skimming in either species. I am grateful to Dr. N. Philip Ashmole for advice on preparation of this note. — Karl Eric Tolonen, Peabody Museum of Natural History, Division of Vertebrate Zoology, Yale University, New Haven, Connecticut 06S20, 25 September 1969. A putative skeletal specimen of the Flammulated Owl with Alabama locality data. — Several years ago Gid E. Nelson, Jr., gave me over 100 bird skeletons, among which was the complete skeleton and rhamphotheca of a fully grown, small owl. The specimen bears the locality of Shelby County, Alabama. The original label lists Montevallo, where Nelson then resided, however, no town is indicated in his catalog. The date listed is November 1953. The sex was not determined. Although previously identified as Otus asio, study of its remains indicates the specimen is from a smaller species of Otus, which on geographic grounds must be the Flammulated Owl i O. flamrneolus) . The smooth texture of the surface of the bones indicates the bird is fully grown and thus its size can be compared with other adult specimens. Ten species of Otus occur in the Western Hemisphere north of South America (Eisenmann, 1955; Peters, 1940). Measurements of the culmen for the 9 species excluding 0. flamrneolus range from 10.5 to 17.5 mm (Ridgway, 1914; Wetmore, 1968). The range for the latter species is 8.5 to 10 mm. The rhamphotheca of the Alabama Otus is free from the under- lying bone and worn slightly from the maceration cleaning process, but its culmen cer- tainly measured less than 10 mm. Tbe diminutive Flammulated Owl is known to have especially small feet (Miller, 1933). To support further the identity of the specimen as 0. flammeolus I compared its tarso- metatarsal length of 22.6 mm with that of 5 species of Otus, including the only 3 recorded from the United States (A.O.U., 1957). A total of 100 Otus asio ranged from 28.3 to 37.7 mm with a mean of 32.85. This sample consists of 9 North American races including the small western O. a. gilmani. 0. a. floridanus is represented by 30 individuals, 19 of which are smaller than all specimens of other races. The tarsometatarsus ranged from 28.3 to 32.8 mm with a mean of 30.69 in these 0. a. floridanus. For the remaining 70 specimens the range is 31.1 to 37.7 with a mean of 33.77. No sexual dimorphism in tarsometatarsal length was evident. Two 0. trichopsis measure 31.0 and 32.0 mm. Four O. flammeolus range from 21.9 to 24.3 (mean 23.00) which nicely encompasses the measurement of the unknown. One specimen of tlie Old World 0. spilocephalus measures 28.9 mm, too large to include the unknown. However, one 0. scops, which some workers consider conspecific with 0. flammeolus (Eisenmann, 1955), measures 23.7 mm. Assuming the owl is a species known to inhabit North or Central America, measurements indicate it is 0. flammeolus. Circumstantial evidence supports the contention that the specimen, indeed, did come from Shelby County, Alabama.. All but one of the 100 specimens given me were collected in the same county. Nelson never collected within the known range of 0. flam- meolus nor did he have any students that did, and no discrepancies between any of his specimens and their appended data have been noted. Alabama College, where Nelson then was employed, is a small school and most of the students came from nearby. He can think of no persons locally who kept live birds. Nelson did not shoot the owl and suspects it was found dead, although he cannot recall the specific incident (all pers. comm.). 224 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 These factors do not eliminate the possihlity that the specimen came from elsewhere and was transported, intentionally or accidentally, to Alabama. Similar criticism can be levied against most specimens and the problem is going to become increasingly acute as man increases in number and mobility. I suggest as a general policy that if an investi- gator can find no evidence to the contrary such distribution records he published along with the circumstances and leave the decision of the validity of the record to the reader. For those willing to accept this record, it constitutes the first Flammulated Owl from Alabama, and only the second from eastern United States. Normally the species is found in western North America from British Columbia to Guatemala, however, one was taken live at Baton Rouge, Louisiana, on 2 January 1949 (Lowery, 1955). Again if accepted, this record has implications regarding the migratory status of the species which at present is controversial (Johnson, 1963). It is common for migratory birds that breed in western North America to appear in southeastern United States in fall and winter, and an above average flux occurred in 1953 (Audubon Field Notes, 1954). It seems far less likely that a sedentary land bird would stray almost 1,000 miles from its normal range. An additional value of this record is to make people aware of the possibility of over- looking specimens of the Flammulated Owl. Nelson is an ornithologist by training yet he handled this specimen without ever realizing it was something other than the locally common Otus asio. I am grateful to Sievert A. Rohwer who measured the large series of Otus asio in the University of Kansas Museum of Natural History, Ned K. Johnson who loaned certain specimens from the University of California Museum of Vertebrate Zoology, and Norman L. Ford who corroborated my identification. The remaining measurements were taken from specimens in the Pierce Brodkorb collection at the University of Florida, the United States National Museum, and my own collection. American Ornithologists’ Union. 1957. Check-list of North American birds. Fifth Ed. Amer. Ornithol. Union, Baltimore. Audubon Field Notes. 1954. Regional reports, winter season, Central Southern and Florida regions. 8:256-258, 246-248. Eisenmann, E. 1955. The species of Middle American birds. Trans. Linnaean Soc. New York, 7:1-128. Johnson, N. K. 1963. The supposed migratory status of the Flammulated Owl. Wilson Bull., 75:174-178. Lowery, G. H., Jr. 1955. Louisiana birds. Louisiana State Univ. Press, Baton Rouge. Miller, L. 1933. A Pleistocene record of the Flammeolated Screech Owl. Trans. San Diego Soc. Nat. Hist., 7:209-210. Peters, J. L. 1940. Gheck-list of birds of the world. Harvard Univ. Press, Cambridge. Ridgway, R. 1914. The birds of North and Middle America. Bull. U. S. Natl. Mus. No. 50, Pt. 6. Wetmore, a. 1968. The birds of Panama. Part 2. Smithsonian Misc. Colls, vol. 150. Smithsonian Inst. Press, Washington. Glen E. Woolfenden, Department of Zoology, University of South Florida, Tampa, Florida 33620, 11 April 1969. Juno 1970 Vol. 82, No. 2 GENERAL NOTES 225 The double -scrateh in the Seaside Sparrow. — Harrison’s ( Wilson Bull., 79:22-27, 1967) list of genera of the subfamily Emherizinae for which the double-scratch had been recorded did not include Ammospiza. On 8 December 1968 I observed a captive Seaside Sparrow {Ammospiza marilima) en- gage in the double-scratch several times in a period of a few minutes. This backward- kicking movement of both feet was performed while the bird was in an indoor 10 X 12 feet room, the floor of wdiich was covered with dirt and had Spartina alternijlora stalks stuck into and held erect by the dirt. The bird double-scratched in a small open area of loose dry dirt with a few millet seeds scattered about. Whenever I have observed this species feeding in the wild, it generally fed in mud, walking about in a deliberate fashion. But an occasion for the use of the double-scratch might be provided by the occurrence at times in tidal marshes of extensive drifts of Spartina seed (which is eaten by this generally insectivorous bird). The fact that feeding Seaside Sparrows are difficult to observe in the thick vegetation of a salt marsh may help explain the lack of previous reports of this double-scratch behaviorism from this species — Frank Enders, Department of Zoology, Duke University, Durham, N.C. 27706, 1 April 1969. Nest-huilding, incubation jreriod, and fledging in the Black-chinned Humming- bird.— On 14 April 1964 a female Black-chinned Hummingbird {Archilochus alexandri) appeared in the English ivy (Hedera helix) outside our family room in Phoenix, Arizona, apparently looking for a nesting site. It continued to look on 15 April, selected a spot on 16 April and worked on the nest throughout the day. On 17 April it started working at 07:00 and continued building during most of the day. It was still working on the nest on 18 April but not as consistently as on the preceding days. The nest appeared to be finished in 19 April. The nest was two meters above the ground and 0.25 meters from the picture window. It was constructed of oleander seeds (Nerium oleander), spider webs, feathers, and mulberry blossoms (Morus sp.). The female spent about 15 seconds at the nest arranging material and was gone about a minute and a half before returning with additional material. This was the pattern on 17 April. Both eggs were laid on 20 April, one early in the morning and the other late in the afternoon. The female began incubating on 21 April. The male was not seen. On 3 May the female added hits of white paint from our house to the outside of the nest. One egg hatched on 7 May after an incubation period of 16 days. The other egg ditl not hatch. The female began feeding the nestling on 8 May. The young bird moved out of the nest at 15:00 on 28 May, returned at 16:30, and left the nest at 18:20. It remained in the ivy vines for two days, while the female continued to feed it. I wish to thank E. M. Reilly, Jr., and Stephen M. Russell for reading and criticizing this note, and Eleanor Radke for putting my notes into correct form. — Salome Ross Demaree, 148 West Rose Lane, Phoenix, Arizona 85013, 16 June 1969. Activity of migrant thrushes as determined liy radio-telemetry. — Durin g the spring and fall Hylocichla thrush migrations from 1965 through 1968, 88 thrushes were tagged with radio-transmitters as described in Graher {Audubon Mag., 67:368-374, 1965), and in Cochran et al. (Living Bird, 6:213-225, 1967). 226 THE WILSON BULLETIN J line 1970 Vol. 82, No. 2 Due to signal propagation characteristics, even slight movements of radio-tagged birds in., 275 pp., 18 photos. $5.95. From the book’s jacket: “Written with wit and affectionate irreverence by Geoffrey Heilman, this book is an anecdotal history of the remarkable men — financiers, scientists, philanthropists, and eccentrics — who have been associated with the greatest natural history museum in the world. But, chiefly, it is a celebration of the growth of a renowned institu- tion, repository for 16,000,000 mammals, minerals, meteorites, fossils, fish, insects and birds, and lodestar to 3,000,000 visitors a year.” Collected papers in Honor of Lyndon Lane Hargrave. Edited by Alliert H. Scbroeder. Museum of New Mexico Press, Santa Fe, 1968: 6 x 9 in., paper covered, 169 pp. No price given. Among the ten papers are the following four of ornithological import: Birds and Feathers in Documents Relating to Indians of the .Southwest (pp. 95-114). Albert H. Schroeder. 240 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 Limb Measurements of the Extinct Vulture, Coragyps occidentalis: With a Description of a New Subspecies (pp. 115-128). Hildegarde Howard. The Instability of the Distribution of Land Birds in the Southwest (pp. 129-162). Allan R. Phillips. A Hairy Woodpecker from Petrified Forest National Park, Arizona ( pp. 163-164). Norman G. Messinger. Songbirds in Your Garden. By John K. Terres. New expanded edition. Thomas V. Crowell Company, New York, 1968: 6% X 914 in., xvi + 256 pp., illus. with line draw- ings by Matthew Kalmenoff. $6.95. This is a thorough revision of the original edition published in 1953. Besides a larger format with many new line drawings and an updating of all information, the new edition features an additional chapter on how to build a bluebird trail. “Songbirds in Your Garden” is essentially a guide to attracting birds about the home, but includes many first-person anecdotes by the author, thus making it highly readable as well as instruc- tive.— O.S.P. Animal Communication: Techniques of Study and Results of Research. Edited by Thomas A. Sebeok. Indiana University Press, Bloomington, 1968: 614 X 914 in., xviii + 686 pp., many figs. $20.00. From the book’s jacket: “Twenty-four original articles by world-renowned experts in the fields of zoology and psychology present an extensive survey of the ‘state of the art’ as of the late 1960’s.” The articles are grouped under five headings: Introduction (one article by the editor). Techniques of Study (four articles). Some Mechanisms of Com- munication (four articles). Communication in Selected Groups (nine articles). Implica- tions and Applications (six articles). The article on birds by Barbara 1. Hooker, a graduate student at New Hall College, Cambridge, is restricted to vocal communication and is essentially a brief review of tbe subject. This issue of The Wilson Bulletin was published on 5 June 1970. Editor of The Wilson Bulletin GEORGE A. HALL Department of Chemistry West Virginia University Morgantown, West Virginia 26506 Editorial Advisory Board William C. Dilger Douglas A. James William A. Lunk Andrew J. Meyerriecks Helmut C. Mueller Robert W. Nero Kenneth C. Parkes Glen E. Woolfenden Ornithological Literature Editor Peter Stettenheim Box 79, Plainfield, New Hampshire 03781 Suggestions to Authors Manuscripts intended for publication in The Wilson Bulletin should be neatly type- written, double-spaced, and on one side only of good quality white paper. Tables should be typed on separate sheets. Before preparing these, carefully consider whether the material is best presented in tabular form. Where the value of quantitative data can be enhanced by use of appropriate statistical methods, these should be used. Follow the .40U Check-hst (Fifth Edition, 1957) insofar as scientific names of United States and Canadian birds are concerned unless a satisfactory explanation is offered for doing otherwise. Use species names (binomials) unless specimens have actually been handled and subsequently identified. Summaries of major papers should be brief but quotable. Where fewer^ than five papers are cited, the citations may be included in the text. All Citations in “General Notes” should be included in the text. Follow carefully the style used m this issue in listing the literature cited; otherwise, follow the “Style Manual for Biological Journals” (1964. AIBS). Photographs for illustrations should be sharp, have good contrast, and be on gloss paper. Submit prints unmounted and attach to each a brief but adequate legend. Do not write heavily on the backs of photographs. Diagrams and line drawings should be in black ink and their lettering large enough to permit reduction. Authors are requested to return proof promptly. Extensive alterations in copy after the type has been set must be charged to the author. Notice of Change of Address If your address changes, notify the Society immediately. Send your complete new address to the Treasurer, William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. He will notify the printer. The permanent mailing address of the Wilson Ornithological Society is: c/o The MUSEUM of Zoology, The University of Michigan, Ann Arbor, Michigan 48104. Persons having business with any of the officers may address them at their various addresses given on the back of the front cover, and all matters pertaining to the Bulletin should be sent directly to the Editor. PAST PRESIDENTS OF THE WILSON ORNITHOLOGICAL SOCIETY • J. B. Richards, 1888-1889 Lynds Jones, 1890-1893 Willard N. Clute, 1894 R. M. Strong, 189^1901 Lynds Jones, 1902-1908 F. L. Burns, 1909-1911 W. E. Saunders, 1912-1913 T. C. Stephens, 1914^1916 W. F. Henninger, 1917 Myron H. Swenk, 1918-1919 R. M. Strong, 1920-1921 Thos. L. Hankinson, 1922-1923 Albert F. Ganier, 1924-1926 Lynds Jones, 1927-1929 J. W. Stack, 1930-1931 Josselyn Van Tyne, 1935-1937 Margaret Morse Nice, 1938-1939 Lawrence E. Hicks, 1940-1941 George Miksch Sutton, 1942-1943 S. Charles Kendeigh, 1943—1945 George Miksch Sutton, 1946-1947 Olin Sewall Pettingill, Jr., 1948-1950 Maurice Brooks, 1950-1952 W. J. Breckenridge, 1952-1954 Burt L. Monroe, 1954-1956 John T. Emlen, Jr., 1956-1958 Lawrence H. Walkinshaw, 1958-1960 Harold F. Mayfield, 1960-1962 Phillips B. Street, 1962-1964 Roger Tory Peterson, 1964^1966 J. M. Shaver, 1932-1934 Aaron M. Bagg, 1966-1968 H. Lewis Batts, Jr., 1968-1969 PAST SECRETARIES OF THE WILSON ORNITHOLOGICAL SOCIETY Lynds Jones, 1888-89 J. Warren Jacobs, 1890-91, 1893 Willard N. Clute, 1892 William B. Caulk, 1894 J. E. Dickinson, 1895-97 W. L. Dawson, 1898-1901 John W. Daniel, Jr., 1902-05 Frank L. Burns, 1906 Benj. T. Gault, 1907—11 C. W. G. Eifrig, 1912-13 Orpheus M. Schantz, 1914 Thos. L. Hankinson, 1915-16 G. A. Abbott, 1917 Albert F. Ganier, 1918-22 Gordon Wilson, 1923-25 Howard K. Gloyd, 1926-28 Jesse M. Shaver, 1929-31 Lawrence E. Hicks, 1932-36 Olin Sewall Pettingill, Jr., 1937—41 Maurice Brooks, 1942-46 James B. Young, 1947-48 Harold F. Mayfield, 1948-51 Phillips B. Street, 1952-55 Fred T. Hall, 1956-57 Aaron M. Bagg, 1958-61 Pershing B. Hofslund, 1962-1966 Tlie Wilson Bulletin PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W, VA. VOL. 82, NO. 3 SEPTEMBER 1970 PAGES 241-352 MUS. COMP. 200LL LIBRARY. OCT 91970 harvard university The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President — William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. First Vice-President — Pershing B. Hofslund, Dept, of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812. Second Vice-President — Kenneth C. Parkes, Carnegie Museum, Pittsburgh, Pennsylvania 15213. Secretary — Jeff Swinebroad, 8728 Oxwell Lane, Laurel, Maryland 20810. Treasurer — William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. Elected Council Members — C. Chandler Ross (term expires 1971) ; Ernest P. Edwards (term expires 1972); Elden W. Martin (term expires 1973). Membership dues per calendar year are: Active, $8.00; Sustaining, $15.00; Life memberships, $200 (payable in four installments). The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new books; members and friends are invited to maintain the fund by regular contribution, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 104 periodicals as gifts and in exchange for The tTilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer (small sums in stamps are acceptable). A complete index of the Library’s holdings was printed in the September 1952 issue of The Wilson Bulletin and newly acquired books are listed periodically. The Wilson Bulletin The official organ of the Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Morgantown, West Virginia. The subscription price, both in the United States and elsewhere, is $10.00 per year. Single copies, $2.50. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most hack i.s8ues of the Bulletin are available (at $2.50 each) and may be ordered from the Treasurer. Special prices will be quoted for quantity orders. All articles and communications for publications, books and publications for reviews should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, Michigan. Second class postage at Lawrence, Kansas, U.S.A. 66044 Allen Press, Inc., Lawrence, Kansas 66044 THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society VoL. 82, No. 3 September 1970 Pages 241-352 GONTENTS The Nesting Ecology and Reproductive Performance of the Eastern Meadowlark John L. Roseberry and W. D. Klirnstra 243 Dominance-Subordination in Caged Groups of House Sparrows John R. Watson 268 Avian Bill- wiping George A. Clark, Jr. 279 Egg Teeth and Hatching Methods in some Alcids Spencer G. Sealy 289 Growth Rates and Sex Ratios of Red-winged Blackbird Nestlings Larry C. Holcomb and Gilbert Twiest 294 CowBiRD Parasitism and Nesting Success of Lark Sparrows in Southern Oklahoma George A. Newman 304 Dust-bathing Sites Selected by Ruffed Grouse Dale Hein 310 Observations of the Breeding Biology of the Vermilion Flycatcher in Arizona W alter Kingsley Taylor and Hugh Hanson 315 General Notes ADDITIONAL NOTES ON THE PLUMAGES OF THE REDHEAD {AYTHYA AMERICANA) Milton W\ W eller 320 OBSERVATIONS ON PREMIGRATORY MOVEMENTS OF HAND-REARED MALLARDS James J. Zohrer 323 TRUMPETER SWAN CARRYING YOUNG Donald A. Hammer 324 NOTES ON THE FOODS OF JUVENILE BLACK-BELLIED TREE DUCKS Eric G. Bolen and John J . Beecham 325 SUCCESSFUL RECONSTRUCTION OF ACTIVE BALD EAGLE NEST Thomas C. Diinstan and Melvin Borth 326 TERRITORIAL CONFLICT IN THE AMERICAN WOODCOCK Frederic W' . Davis 327 CIIUCK-WILL’s-WIDOW in CONNECTICUT Eugene S. Morion 329 PREDATION OF A BLACK RAT SNAKE ON YELLOW-SHAFTED FLICKER NESTLINGS Jerome A. Jackson 329 WING FLASHING IN A BROWN THRASHER AND CATBIRD Edwin D. Michael 330 RE-EVALUATION OF TWO SUPPOSED HYBRID BIRDS Richard C. Banks 331 THE AVIFAUNA OF THE SAND DRAW LOCAL FAUNA (aFTONIAN) OF BROWN COUNTY, NEBRASKA J. Alan Eeduccia 332 Ornithological News 335 Ornithological Literature 336 Gordon H. Orians and Gene M. Christman, A Comparative Study of the Behavior of Red-winged, Tricolored, and Yellow-headed Blackbirds, reviewed by Robert W. Nero; Merrill Wood, A Bird-Banders Guide to Determination of Age and Sex of Selected Species, reviewed by Robert C. Leberman; John K. Terres, Erom Laurel Hill to Siler’s Bog, reviewed by Louise de Kiriline Lawrence; William Service, Owl, reviewed by Sally H. Spofford. Publication Notes and Notices 314, 319 Proceedings of the Fifty-First Annual Meeting Jeff Swinebroad, Secretary 343 THE NESTING ECOLOGY AND REl’UODUCTIVE PERFORMANCE OF THE EASTERN MEADOWLARK John L. Roseberry and W. D. Klimstra This paper reports on a study of 450 nests of the Eastern Meadowlark [Sturnella magna) near Carbondale, Illinois from 1960 to 1967. Data were collected in conjunction with long-term field studies of the Bobwhite [Colinus virginianus) conducted jointly by the Illinois Natural History Sur- vey, Urbana and the Cooperative Wildlife Research Laboratory of Southern Illinois University. Despite the abundance of meadowlarks, their wide-spread distribution, and membership in a relatively well-studied family (Icteridae), the nesting habits and breeding biology of the species have received surprisingly little attention. This probably reflects the difficulties involved in finding large numbers of these well-concealed nests. Nice’s (1957) classic review of the nesting success of 17 open-nesting, altricial species contains no reference to meadowlarks; nor does Davis’ (1955 ) list of studies on clutch size of 53 species of birds. Saun- ders (1932) gave breeding dates, nesting success, and clutch size of Eastern Meadowlarks near Ithaca, New York. Lanyon (1957) reported on nest suc- cess and clutch size of both Eastern Meadowlark and Western Meadowlark {Sturnella neglecta) near Madison, Wisconsin, and Johnston (1964) noted breeding season and clutch size of both species for Kansas. Sample sizes re- flected by these studies ranged from 16 to 62 nests. Data presented by Gross {in Bent, 1958) represent largely the contribution of Saunders (1932). In addition to these studies, numerous accounts of a few nests are reported in the literature but the small sample size, lack of certain details, and variation in observational and reporting techniques make them of limited value. STUDY AREAS AND METHODS Studies were conducted primarily on the Carbondale Bobwhite Quail Research Area, a 1450-acre tract of privately-owned farms located 6 miles northeast of Carbondale in Jack- son and Williamson Counties, Illinois. The topography is gently rolling and soils are of low productivity. Meadowlark nesting habitat is mainly represented by permanent pas- tures and hayfields which occupy some 27 per cent of the area; approximately 31 per cent of the acreage is planted yearly to corn and soybeans, 10 per cent is woods and 20 per- cent is idle or fallow land. One 50.5-acre pasture (40 acres of nesting cover) on the west border of the Research Area, hereafter referred to as Bigler’s pasture, served as a focal point for studies during the latter phase of the project. Some nests were also located on University-owned farmland just south and west of the main campus of Southern Illinois University in Jackson County. Nest searching methods were identical to those employed in finding Bobwhite nests. Walking abreast, at intervals of 4 feet and with the aid of walking sticks, crews of four 243 244 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 to eight men systematically searched all cover. From 1960 to 1963, the entire Carhondale Research Area, excluding woodlots and intertilled cropland, was searched at least twice; in 1964, selected portions of this area were hunted and in 1965, one field on the Research Area (Bigler’s pasture) and selected fields on the University property were hunted. In 1966 and 1967 a limited amount of nest hunting was conducted on the University property. From 1960 to 1963, nest hunting was begun around 20 May and terminated 10 Septem- ber; in 1964 hunting was conducted during the periods of 10-19 June and 13-25 August. In 1965, fields were searched from 10-19 May and 16-25 June. All fields searched were covered at least twice except during 1965, 1966, and 1967 when portions of the University properties were hunted only once. When found, each nest was marked; active nests were revisited every 3-4 days until final outcome was established. When nests were no longer active, fate, approximate date of egg laying, number of eggs, plant materials in the nest, degree of overhead cover and concealment, direction of nest entrance and slope, and drainage at the nest site were recorded. THE NEST Construction. — Actual nest construction was not witnessed during the study ; this activity has been described by Saunders (1932:178-180). He believed that only the female participated in nest building, which normally took from 3 to 5 days, even though numerous earlier workers had credited both sexes. Lanyon (1957) found that earlier nests took from 6 to 8 days to complete but later nests were built in as few as 4 days. Nests were virtually always in a slight bowl-like depression. This bowl, nor- mally from 1 to 3 inches deep and 4 to 4% inches in diameter, was apparently scraped out by the bird prior to nest construction but on occasion, deeper natural depressions such as hoofprints of cattle or horses were used. As de- scribed in detail by Saunders (1932:180-181), a typical meadowlark nest consists of (1) an inner subspherical shell composed of a shallow bowl of finely woven grass stems on which the eggs are laid and a thin subspherical superstructure of coarser stems placed between the shell and the ground and (2 ) an outer covering of coarse grass or other material bent over the shell to form a canopy. Most nests found during our study conformed to the above type, however, there were numerous exceptions. Form and degree of construction seemed at least partially dependent upon time of nesting season and type of cover in the immediate area. Some nests were large structures with thick sides and heavy, complete roofs closely resembling those of the Bobwhite while others lacked both sides and top, consisting only of the inner subspherical shell of fine stems with some coarser plant material beneath it. The most common nest type was intermediate between these extremes; it consisted of a complete subspherical structure, often tilted at a 20° to 30° angle with the back of the nest built up to form a partial canopy. Of 220 used nests, 17.3 per cent lacked a canopy; Roseberry and Klimstra MEADOWLARK NESTING ECOLOGY 245 -14.5 per cent had a partial canopy; and 38.2 per cent had a full canopy. Oc- casionally, nests were located so as to use the natural canopy provided by lodged grasses. The time of nesting clearly influenced nest architecture. Of those nests built prior to 26 May, 21.0 per cent lacked a canopy, 53.2 per cent had a partial canopy, and 25.8 per cent had a full canopy. Of those built after 26 May, only 12.1 per cent lacked a roof, 36.4 per cent had a partial roof, and 51.5 per cent had a full canopy. This increase in the construction of elaborate nests possibly reflected seasonal enrichment of the vegetation. Interestingly, Lanyon (1957) found that early nests generally took from 2 to 4 days longer to com- plete than later nests yet our data showed the former to be generally less elaborate than the latter. Several writers (Gross in Bent, 1958; Saunders, 1932; Lanyon, 1957; and Thoms, 1924) reported nests with obvious trails, and even covered passage- ways or tunnels, leading to them through the vegetation. The presence of such covered passageways was not observed during our study although in a few in- stances, rather obvious runways were noted leading to the entrance of the nest. Building materials. — As noted by Saunders (1932) and circumstantially confirmed during our study, the female tended not to use plants present at the nest site for the inner lining of the nest but almost always brought this ma- terial from a considerable distance. On our study areas, the material most commonly used for the inner subspherical shell was the fine-stemmed, grass- like rush Juncus tenuis. This plant was seldom found growing at the nest site. Of 853 plant occurrences in 406 nests, grasses and grass-like forms {Juneus and fine-stemmed legumes) accounted for 823 or 96.5 per cent (Table 1). In all, 32 individual plant species were identified in 406 nests. Juncus, whose use was limited almost exclusively to the inner lining, occurred in 63.3 per cent of the nests. Eine stems of bluegrass or lespedeza were most often used as substitutes for Juncus in the nest lining. Meadow fescue at times was found in the canopy but mainly was used in the subspherical superstructure. When fescue was not available, other coarse-stemmed species such as timothy, or- chard grass, wheat, and rye were used. Of the nests examined, 81.6 per cent were constructed of more than one species of plant with 56.7 per cent con- taining two and 21.4 per cent containing three; five different species were the most found in any one nest. Concealment and drainage. — Nests were rated on the basis of concealment to the human eye, a factor influenced by the amount and type of vegetation in which the nest was situated and to a lesser extent the presence or absence of a nest canopy. Of 377 nests, 19.1 per cent were judged to have excellent con- cealment. These were difficult to see even when the location was known within 246 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 1 Plant Materials Used in the Construction of 406 Meadowlark Nests Species Frequency of Number occurrence Per cent Rush (Juncus spp., mostly tenuis) 257 63.3 Cheat {Bromus secalinus) 168 41.4 Meadow fescue {Festuca elatior) 95 23.4 Bluegrass (Poa compressa and pratensis) 77 19.0 Common and Korean lespedeza {Lespedeza striata 46 11.3 and stipulacea) Panic grasses (Panicum spp.) 30 7.4 Common tickle grass {Agrostis hyemalis) 27 6.7 Small wild barley {Hordeum pusillum) 24 5.9 Paspalums (Paspalum spp.) 18 4.4 Red clover {Trifolium pratense) 17 4.2 Timothy (Phleum pratense) 15 3.7 Orchard grass {Dactylis glomerata) 14 3.4 Foxtail grasses {Setaria spp.) 10 2.5 Crabgrasses (Digitaria spp.) 9 2.2 Wheat {Triticum aestivum) 8 2.0 Slender fescue {Festuca octo flora) 6 1.5 Corn {Zea mays) 4 1.0 Broomsedge {Andropogon virginicus) 4 1.0 Lance-leaved ragweed {Ambrosia bidentata) 4 1.0 Redtop {Agrostis alba) 4 1.0 Plantains i Plantago spp.) 3 0.7 Low hop-clover {Trifolium procumbens) 3 0.7 Oak (leaves) {Quercus spp.) 2 0.5 Rye {Secale cereale) 2 0.5 Yarrow {Achillea millefolium) 1 0.2 Alsike clover {Trifolium hybridum) 1 0.2 Elm (leaves) {Ulmus sp.) 1 0.2 Sedge iCarex sp.) 1 0.2 Rough huttonweed iDiodia teres) 1 0.2 Dropseed {Sporobulus sp.) 1 0.2 a square yard or so; often, they became visible only after the vegetation was parted directly over them. A rating of good was given to 47.8 per cent of the nests; these were visible from above without intense searching. Ratings of fair and poor were given to 28.9 per cent and 4.2 per cent, respectively; the latter classification applied to nests visible from several yards away. Nice ( 1 964 ) found a positive correlation between nest success of the Song Spar- row { Melospiza melodia) and degree of nest concealment; but, no such rela- tionship was evident from our data. Roseberry and Klimstra MEADOWLARK NESTING ECOLOGY 247 Table 2 Orient.\tion of Meadowlark Nests in South-central Wisconsin AND Southern Illinois Direction Nest Facing WisconsiiU Illinois- Number Per cent Number Per cent North 19 14.5 49 14.0 Northeast 23 17.6 74 21.2 East 36 27.5 48 13.7 Southeast 13 9.9 39 11.1 South 11 8.4 33 9.5 Southwest 5 3.8 39 11.1 West 5 3.8 29 8.3 Northwest 19 14.5 39 11.1 Totals 131 100.0 350 100.0 ^ Calculated from Lanyon (1957, Table 8, p. 42). - Our stud\ . When nesting in areas of gently rolling or moderately hilly terrain, meadow- larks showed a definite affinity to slopes as opposed to flat crests or valleys. Of 412 nest sites, drainage was considered excellent for 37.1 per cent and good for 45.2 per cent. These represented nests which would not be expected to flood or wash out except possibly under torrential conditions. Only 12.4 per cent and 5.3 per cent of the nest sites were classified as having fair or poor drainage, respectively. The latter type included nests which could be flooded by surface runoff during moderate to heavy rain showers. Orientation. — Earlier workers have noted that orientation of meadowlark nests appears to be non-random. In northern Illinois, Sandborn and Goelitz (1915) found eight nests of S. magna, all of which had entrances facing south. Saunders ( 1932), from observations of 29 S. magna nests in New York, con- cluded that orientation might be in any direction but suggested a possible cor- relation with the location of male song perches. Lanyon (1957:42 ), reporting on 131 nests of S. magna and S. neglecta in Wisconsin, found nests to face predominantly to the north and east. He found no relationship with position of the nest within the territory or with location of male song perches hut stated: “The effect of the prevailing winds, particularly during rain or sleet storms, is to depress the vegetation toward the north and east, thus encourag- ing the same orientation in nidification. ’ As shown in Table 2, Lanyon’s (1957) data showed 59.6 per cent of 131 nests faced north, northeast, or east with east the modal direction. In our study, 48.9 per cent of 350 nests faced in one of these three directions with 248 THE WILSON BULLETIN September 1970 Vol. 82. No. 3 northeast being the modal direction; a chi square test showed this orientation pattern not to be due to chance ( P < 0.001 ) . Interestingly, 48.7 per cent of 915 Bobwhite nests located over a 15-year period in the same general area also faced either north, northeast, or east (Klimstra, unpublished data). Seemingly then, the factor or factors responsible for this non-random orientation simi- larly affect both the Bobwhite and the meadowlark. As in Wisconsin (Lanyon, 1957), nests on our study areas also tended to face away from prevailing winds. Records (unpublished data, Murdale Airport, Carbondale) from 1954 through 1963 indicated that during the period of 1 April through 21 July, winds blew toward the north and north-northeast 33 per cent of the time and field observations confirmed that vegetation, especially grasses, tended to be lodged in those directions. Nest orientation also seemed related to the direction of slope upon which the nest was located. Hann (1937) noted that 31 of 36 (86 per cent ) Oven- bird (Seiurus aurocapillus) nests faced down the slope at some angle although he found no affinity for any one particular direction. In our study, 47.6 per cent of the nests faced down slope at some angle while only 29.8 per cent faced up the slope {P < 0.001). This tendency to face nests down slopes does not entirely explain the non-random orientation as 44.7 per cent of those nests built on slopes other than north, northeast, or east faced in one of these three directions (P<0.05). Unused nests. — Saunders (1932) observed that females commonly began and worked on several nests before one site was completed. In our study, 126 of 388 (32.5 per cent) nests were thought not to have been used. Some of these were only partially built but others were indistinguishable from active nests with respect to construction. Regarding degree of construction, 32.0 per cent of the unused nests had no canopy and only 18.0 per cent had full cano- pies as compared to 17.3 per cent and 38.2 per cent, respectively, for used nests. Saunders (1932) believed that the partial building of several nests occurs just prior to the female attaining the sexual and physiological stage necessary for intensive nest building. Our data tend to support this in that unused nests were much more common during early stages of the breeding season. While in most instances it was impossible to determine the date of commencement of these unused nests, for those in which dating was possible, virtually all were begun before 12 May. THE BREEDING SEASON The beginning and duration of a species’ nesting season are important to overall reproductive performance. They determine the climatic conditions, or range of conditions, the young must cope with, and whether sufficient time is Roseberry and Klimstra MEADOWLARK NESTING ECOLOGY 249 q: ui CD 2 3 5 ■ 4 ■ 3 - T 1 1 1 1 1 1 1 1 1 1 1 1 I 8 15 22 29 6 13 20 27 3 10 17 24 I 8 15 22 APRIL MAY JUNE JULY Fig. 1. Initial egg laying dates for 54 Eastern Meadowlark nests, 1965. available to the adults for raising more than one brood or renesting after nest failure. Our study did not attempt to correlate beginning of nesting with environ- mental factors, and, as the start of nest hunting efforts was not uniform from year to year, we were unable to determine whether yearly variations in nesting time occurred. It has been established that meadowlarks breed later in the northern parts of their range (Saunders, 1932; Gross in Bent, 1958; Lanyon, 1957; Johnston, 1964). At approximately 38° latitude (southern Illinois, Kan- sas, Virginia), meadowlarks apparently begin laying around 10-15 April, end around 15-22 July, with peak activity from 29 April— 5 May. At 42^3° lati- tude (Massachusetts, New York, Wisconsin) earliest laying is from about 23 April-5 May, latest from 4-15 July, with heaviest laying around 13 May. Our study provided estimated dates of initial egg laying for 129 nests. Dates were calculated by backdating from the particular event (laying, incu- bating, brooding) in progress when the nest was discovered. Unfortunately, nest searching efforts during the first four years of the study were begun in late May or early June; consequently, many of the nests found were too old to permit estimation of egg-laying dates. Those nests which were dated (75) during these years cannot be used to analyze the entire nesting season as they mostly represent mid- to late-season efforts. In 1965, nest searching was begun in early May, and the 54 nests dated during that year were representative of the entire breeding season. The earliest recorded date of egg laying was 14 April with most eggs being laid during the period of 22 April to 12 May, the 250 THE WILSON BULLETIN September 1970 VoL 82, No. 3 modal period being from 29 April to 5 May (Lig. 1 ) . Dates of initial egg lay- ing recorded during 1960-1964, while not reflecting early nesting, can be combined with those from 1965 to analyze the latter portions of the breeding season. It is apparent that on our study areas, meadowlark nesting is virtually completed by 7 July as only 3 (2.3 per cent) of 129 nests were begun after this date. The latest recorded nest was begun on 23 July and hatched on 8 August 1962. No obvious peak for second brood nests is evident (Lig. 1), yet we suspect that most second brood nests were not begun until the middle of May or later. Theoretically, if second brood nests were begun shortly after fledging of the first brood, a second nesting peak should have been evident about 30 days after the first peak. However, as over % of all nests failed at varying times after their commencement, renesting following these failures would tend to be staggered in time, thus smoothing out the nesting curve by overlapping and obscuring second brood nesting peaks. NESTING IN RELATION TO LAND-USE TYPES All land-use types on the Carbondale Research Area except intertilled crop- land and woods were searched for nests from 1960 through 1963; only selected fields were hunted during 1964-1967. Acreage figures used in the calculation of nest densities per land-use type (Table 3) were obtained by mul- tiplying the acreage of each tract by the number of years it was searched. Data from random, non-systematic hunting, i.e. coverage not designed to find all nests in a particular area, were not included in these calculations. A total of 435 nest locations were recorded, however, only 307 nests that contained eggs will be considered here; there appeared to be no major differences in proportions of unused nests among the various types of nesting cover. Saunders (1932) noted that while grasslands and pastures support larger meadowlark populations than other habitats, the birds commonly nest in a wide variety of cover-types. Data from our study indicates that the preferred nesting habitat is pasture, followed in order by hayfields, soilbank fields, win- ter wheat fields, idle, and fallow areas (Table 3). In all these areas, however, the presence of dead grass stems at ground level and the absence of woody vegetation or numerous shrubs in the immediate vicinity appeared to be a pre- requisite for nesting utilization. Height of cover at 204 nest sites ranged from 2 to 30 inches and averaged 14.9; 66.6 per cent of all nests were built in cover 10 to 20 inches high. The fact that nests are sometimes built in rather deep bowls or natural depressions often permitted utilization of areas with little cover; one nest was found in the mowed fairway of a golf course. Pastures. — Condition and composition of pastureland on the study area Kuseberry and Klimstra MEADOWLARK NESTING ECOLOGY 251 MeADOWL.'UZK Table 3 Nest Density in Relation to Land-Use Types Land-use type Acreage searched for nests Nests found' Nests per too acres Pasture grazed 879 120 13.7 ungrazed“ 80 80 100.0 Total 959 200 20.9 Hayfield alfalfa 120 5 4.2 red clover 222 35 15.8 mixed grasses^ 62 11 17.7 Total 404 51 12.6 Soilbank (grasses) 487 25 5.1 Winter wheat^ 83 4 4.8 Idle 558 21 3.8 Fallow 298 6 2.0 Totals 2,789 307 11.0 ^ Used nests only. - First and second year subsequent to removal of cattle. •’ Predominantly meadow fescue, orchard grass, timothy, bluegrass, and cheat. * Two built prior to cutting of wheat, two built in wheat stubble. varied greatly. There was opportunity to compare utilization among lightly grazed to severely overgrazed pastures and one field left ungrazed for 2 years. Also compared were pastures receiving similar grazing pressure hut composed of entirely different floral communities. In all, 200 nests were found on 959 acres of pasture (20.9 nests per 100 acres ) . This, the heaviest utilization of any land-use type, mainly reflected the extremely high number of nests (80) found on one 40-acre pasture during 2 years that it was ungrazed. Nesting utilization of grazed pastures (13.7 per 100 acres I was only slightly greater than hayfields (Table 3). We found an inverse relationship between intensity of grazing and utiliza- tion by nesting meadowlarks. An example is offered by one tO-acre field con- taining approximately 60 per cent meadow fescue, 35 per cent Korean lespe- deza, 5 per cent orchard grass, and no herbs and shrubs. During 1961, 1962, and 1963, the heavy grazing of this field by cattle maintained the vege- tation at a height of about 1 to 3 inches and left only a few scattered clumps of fescue 12 or moze inches in height. During these years, thiee, two, and three nests with eggs, respectively, were found. In 1964, grazing was less in- tense, resulting in a more abundant and uniform distribution of fescue clumps 252 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 and leaving patches of Korean lespedeza up to 5 inches in height. Eleven nests with eggs (19 including unused nests) were found that year, nearly all of which had been built in patches of lespedeza or at the base of isolated clumps of fescue. The most striking example of the effects of grazing on nest estab- lishment was evident in Bigler’s pasture. Herbaceous vegetation in this field consisted mainly of meadow fescue, cheat, lance-leaved ragweed, Korean and common lespedezas, and panic grasses; many other species were also repre- sented. During 1960, the field was heavily grazed and three nests were found ; in 1961 it was severely overgrazed and no nests were found. In 1962, grazing was heavy but less than the previous years and 13 nests were built in the field. In the spring of 1963, the pasture was renovated, manure spread, and Ken- tucky bluegrass seeded on about % of the field and meadow fescue on Vs: 12 nests were found that season. In 1964 and 1965, the field was not grazed and exhibited large areas of dead and lodged stems of bluegrass and vigorous stands of fescue. During these years, 41 and 39 nests with eggs, respectively, were found. Considering both used and unused nests, this field yielded a total of 129 nests in 2 years, a far higher density than was recorded on any other plot during the entire study. Mayfields. — As shown in Table 3, hayfields ranked second to pastures as favored nesting sites with an average density of 12.6 nests per 100 acres. Al- falfa (Medicago saliva) fields were least preferred (4.2 per 100 acres I ; red clover fields yielded 15.8 nests per 100 acres. Nesting was heaviest in a mixed- grass hayfield (mainly orchard grass, meadow fescue, timothy, bluegrass, and cheat) which averaged 17.7 nests per 100 acres over a 2-year period. Alfalfa fields, especially good stands, seemingly lacked sufficient grassy cover at ground level to provide acceptable nesting habitat. This was also apparent in most red clover fields, but portions of these fields were sparse enough to allow the invasion of grasses thus providing some nesting cover. Red clover appeared in 17 nests (Table 1) ; it was, however, always used in conjunction with other, more finely-stemmed species. Alfalfa stems were not found in any nest. Soilhank and wheat fields. — In 1959, five fields on the Research Area totalling 155 acres were placed in the Lederal Soil Bank Program; this acreage was reduced to 135 by 1961. Under provisions of this program, fields were taken out of cultivation and seeded to grasses; mowing was permitted hut fields could not be pastured or used for hay. Meadowlark utilization of these areas was not great; overall density averaged 5.1 nests per 100 acres. Once established, four of the plots displayed dense, uniform stands of meadow fes- cue with some orchard grass and Korean lespedeza; few nesting birds used them. The remaining field, 33 acres of gently sloping land, apparently re- Roseberry aiul Rlimstra MEADOWLARK NESTING ECOLOGY 253 ceivecl a poor initial seeding and remained rather weedy throughout the period of study. During the last 2 years fescue, while retaining good stands in the lower moist areas, virtually disappeared from the dryer slopes and ridges and was replaced hy a variety of invading species, especially common lespedeza, panic grasses, and rough huttonweed. During these two years, this field com- prised only 13.5 per cent of the total soilbank acreage searched but yielded 40.0 per cent of the nests found. Wheat fields, showing a density of 4.8 nests per 100 acres, seemingly did not provide good nesting habitat; this probably reflected a general lack of grasses and fine-stemmed legumes necessary for nest construction. Two of four nests in wheat were built after fields had been harvested. Idle and fallow areas. — Although 558 acres of idle and 298 acres of fallow land (uncultivated for 1 or 2 years) were searched during the study, only 27 used nests were discovered in these habitats (Table 3). This represents a nest density of 3.8 and 2.0 per 100 acres, respectively, the lowest encountered in all types of cover. Fallow fields were thought to be little used because of an absence of suffi- cient grassy cover. In this region, most areas left uncultivated are initially in- vaded by such species as common and Korean lespedeza, plantains (Plwitago spp. ) , wild lettuce {Lactuca spp.), lance-leaved ragweed, cocklebur {Xanthium spp.), and foxtails {Setaria spp.). Cheat, panic grasses, and crabgrass aie early invading grasses, but the amount of dead stems suitable for good nesting material is generally lacking during the year or two subsequent to fallowing. Most idle areas searched were at least 6 years or older and were character- ized by numerous woody shrubs, small trees, and patches of briar (Rubus spp. ) , intermixed with a variety of herbaceous plants and such grasses as cheat, broomsedge, and bluegrass. In many instances, the ground cover with growing grasses and dead and lodged stems looked ideal for nesting cover; however, the presence of numerous herbs and small woody species apparently precluded extensive use by meadowlarks. Those areas which received moderate use were recently idle fields which contained little or no woody cover, yet pro- vided a better ground cover of grasses than did fallowed areas. CLUTCH-SIZE As pointed out by Davis (1955), published clutch-size data usually refer to the number of eggs found in nests presumed to contain complete clutches. In practice, the investigator can rarely he certain that the eggs present represent a complete clutch, i.e. the number of eggs laid in an uninterrupted series. In our study, egg counts of presumably complete clutches were available from 101 nests. Included in this sample were nests discovered while eggs were be- 254 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Seasonal Variation in Table 4 THE Clutch-Size of Meadowlarks Date first egg laid Number of eggs Mean Standard Deviation 2 3 4 5 6 14 April-5 May 0 1 1 6 1 4.78 0.79 6 May-2 June 0 5 11 18 0 4.38 0.74 3 June-30 June 2 12 26 13 0 3.94 0.80 1 July-23 July 0 3 0 2 0 3.80 0.98 Totals 2 21 38 39 1 4.16 0.83 ing deposited and subsequently observed to be incubated, and nests discovered during incubation. Conceivably, this latter group could have included some nests from which one or more eggs had been removed prior to incubation; however, observations from this study and those from a study of over 1,000 Bobwhite nests (Klimstra, unpublished data) clearly suggest that in virtually all instances of nest disturbance by predators, enough eggs (usually all) are affected to make the disturbance easily detectable. Nests found subsequent to destruction or abandonment were excluded from clutch-size calculations, as were nests containing young because of the possibility that unhatched eggs had been removed from the nest by parent birds. The mean number of eggs found in 101 complete clutches was 4.16 ± 0.08. Clutches varied from two to six (Table 4). As explained previously, our sample contained a disproportionately large number of mid- and late-season nests, and, as shown in Table 4, clutch-size tended to decrease as the nesting season progressed. Thus, it seems justified to assume that the mean clutch- size derived may be somewhat low. During 1965, approximately 60 per cent of all nests were started prior to 27 May and 40 per cent after that date; data from all years showed a mean clutch-size of 4.36 for the earlier period and 4.03 for the latter. Using these figures, a prorated mean clutch-size of 4.23 is obtained. The average number of eggs per nests in our study proved considerably lower than previously reported for the Eastern Meadowlark. Lanyon (1957), from 38 nests in Wisconsin, reported a mean clutch-size of 4.81 ± 0.16 with a range of 2-6. Erom Saunders’ (1932:197) New York data, a mean clutch- size of 4.57 ± 0.15 was calculated for 23 nests. Gross (in Bent, 1958) stated that Eastern Meadowlark clutches vary from 3 to 7 with sets of 5 most com- mon and sets of 4 more usual in second brood nests. He also noted that clutches tended to he smaller in the southern part of the nesting range while Saunders (1932) found that clutches in central Oklahoma averaged smaller Roseberry and Klimslra MEADOWLARK NESTING ECOLOGY 255 than those from New York. Our data, indicating smaller clutches than those reported from Wisconsin and New York, would seem to support this. John- ston (1964), however, found a mean of 5.2 eggs (range 4-7) for 26 nests in Kansas which is approximately the same latitude as southern Illinois. Davis (1955) cited numerous studies demonstrating that clutch-size in most species of birds decreases as the nesting season progresses; renesting appar- ently produces fewer eggs than initial nesting. Such seasonal decline in size of meadowlark clutches has been noted also by Johnston (1964), Saunders (1932), Gross {m Bent, 1958), and Lanyon (1957). The latter author found a seasonal decline in the size of Western Meadowlark clutches but data for the eastern species from the same area failed to demonstrate this. We were un- able to differentiate among first and second brood nests and renesting efforts, but our data (Table 4) clearly show a seasonal decline in the number of eggs laid. Average clutch sizes recorded for the periods 14 April-5 May, 6 May- 2 June, 3 June-30 June, and 1 July-23 July were 4.78, 4.38, 3.94, and 3.80. respectively. Size of eggs. — According to Bendire (1895), 201 Eastern Meadowlark eggs in the United States National Museum averaged 27.75 mm by 20.35 mm. The largest egg was 30.78 by 22.61 mm while the smallest was 21.59 by 18.29 mm. Reed (1965) stated that egg size for this species was 27.94 by 20.32 mm but gave no range or sample size. From our study areas, mean length of 17 eggs from 9 nests was 27.97 ± 0.44 mm (range 23.54-30.62) and mean width was 20.69 ± 0.29 mm (range 18.40-23.76). NESTING SUCCESS AND LOSSES Determination of nest fate. — Lack (1954) believed the problems of accu- rately estimating nesting success have not always been appreciated. Mayfield (1960 and 1961) contended that the sampling procedure used in some past nesting studies resulted in overestimating the percentage of successful nests and eggs. Nolan (1963:306) summarized Mayfield’s argument: “Briefly, the error consisted of calculating success from the fates of all nests found while still in use, regardless of the fact that, in many, development had already advanced into the incubation or nestling stages when the nests were discovered. Nests that had failed before they were found were usually disregarded. Such calculations thus overlooked both the success already attained by some nests (and the conimensurately reduced risks ahead) and the losses already incurred by other nests. This kind of sampling . . . tended toward bias by selecting nests already partly successful and then measuring success during that subsequent fraction of their histories in which they were under scrutiny by the in- vestigator. . . . “To avoid this error, a study of observed nest success could be based on nests found at or before the moment the first egg is laid. (Alternatively, it would be theoretically pos- sible for tbe observer to rely on nests found at any stage of development either if his 256 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 coverage of his study area were efficient enough to lead to the discovery of all nests while they were still in use by the birds, or if he could find, recognize, and include in his com- putations nests that had already failed.)” Our calculations of nesting success are based upon the assumption that Nolan’s second contingency was satisfied, that is, all nests, regardless of whether active or terminated, were found (or had equal chance of being found) and recog- nized. Determination of the fate of nests no longer in use did present certain prob- lems. It is extremely unlikely that an investigator can actually witness the cul- mination of the nesting process, even if the nest is kept under observation throughout the active period. Thus, determination of fate must be based gen- erally upon evidence at the nest site. The accuracy of this is contingent not only upon the quality and quantity of the evidence but also upon the investi- gator’s ability to correctly interpret it. Experience gained from the study of hundreds of Bobwhite nests greatly increased our ability to read “sign” at the nest site. However, because hatched meadowlark nests contain no egg frag- ments and because the eggs are much more fragile (apparently because they lack a strong shell membrane), the evidence at meadowlark nest sites was gen- erally less and of poorer quality than at Bobwhite nests. Careful examination of nests known to have contained young which had fledged provided an index to the usual appearance of nests at this stage. While young are in the nest, emergence of the primary wing feathers produces an abundance of flaky, whitish material (feather sheaths) which collects in the bottom of the nest, ultimately sifting down through the lining to the bottom of the nest bowl. This was the primary criterion used to determine if a nest had contained young. Also the interiors of nests that had contained young were generally enlarged. It is possible that predation on young could have gone undetected if the young were removed either prior or subsequent to emergence of their primaries; however, evidence from several nests indicated that removal of young by predators left signs that could be interpreted. Nests found without eggs or fragments and showing no sign of the presence of young or previous use were classified as unused. It is possible that some nests in which eggs were removed by snakes were erroneously placed in this category; however, nest interiors in which females had laid and incubated eggs were thought distinguishable in most cases from those which had never been used. Determination of specific predators was difficult because meadow- lark eggs are extremely fragile and tend to break into tiny fragments once destroyed. While making identification of specific predators difficult, this virtually assured that some egg fragments would remain in a nest destroyed by a carnivore. Nests considered destroyed by predators could, of course, have Koscberry and Klimstra MEADOWLARK NESTING ECOLOGY 257 Table 5 PRODUCTmTY OF Meadowlark Nesting on Study Areas, Southern Illinois Bigler’s pasture All other areas Total Total nests found 170 280 450 Nests of unknown fate 13 49 62 Unused nests 60 66 126 Active nests of known fate 97 165 262 Per cent hatched 23.7 (23) 45.5 (75) 37.4 (98) Per cent fledged 17.5 (17) 38.2 (63) 30.5 (80) Total eggs examined 577 Per cent hatched 42.1 (243) Per cent fledged 33.8 (195) already been abandoned before destruction; but, as will be shown later, this probably occurred very infrequently. Of 450 meadowlark nests found, the fate of 62 could not be determined and 126 were unused; these were not included in computations of productivity. Analysis of nesting success, then, was based upon observations of 262 nests of known fate. The fate of individual eggs and nestlings were based upon ob- servations of only a portion (170) of all nests; these represented nests in which the number of eggs laid, and their ultimate fate were known with reasonable certainty. Success of nests, eggs, and young. — Of 262 active nests, the eggs of 98 (37.4 per cent) hatched and the young of 80 (30.5 per cent) fledged (Table 5) ; a “hatched nest,” as used here, refers to one in which at least one egg hatched and a “fledged nest” is one from which at least one nestling success- fully left the nest. Hatching and fledging success of 577 eggs was 42.1 per cent and 33.8 per cent, respectively. These data indicate a somewhat lower success than previously recorded for meadowlarks and other open-nesting, altricial species. Lanyon (1957) reported a total fledging success of 34.4 per cent for 60 S. magna and 62 S. neglecta nests in Wisconsin. In a review of 35 studies of open-nesting, altricial birds (not including meadowlarks), Nice (1957) found an overall fledging success of 19.3 per cent for 7,788 nests; hatching success of 21,040 eggs was 59.8 per cent while fledging success of 21,951 eggs was 45.9 per cent. Overall productivity (Table 5) was lowered considerably by the extremely high losses incurred on one field of the study area (Bigler’s pasture). Here, only 17.5 per cent of 97 nests fledged young as compared to 38.2 per cent of 258 THE WILSON BULLETIN Sei>tcnil)er 1970 Vol. 82, No. 3 165 nests on all other portions of the study areas. Lactors thought responsible for this differential success will be discussed later. A comparison of success of nests found before and after termination is of interest in light of Mayfield’s comments previously cited (Nolan, 1963:306). This comparison is useful also in determining the possible effects of human visitations to the nest. The percentages of abandoned and preyed upon nests were 2.2 per cent and 3.4 per cent lower, respectively, in nests found while active as eompared to those found after termination; this strongly suggests that careful visitations to the nest did not increase the incidence of abandon- ment or predation. On the other hand, fledging success was 21.3 per cent higher in nests found while active. This seems mainly to reflect the fact that hayfields were hunted after mowing, thus that portion of the nest sample found after termination includes almost all the nests destroyed by mowing. Comparative losses of nests, eggs, and young. — Nesting efforts of birds are usually described in terms of percentage of successful nests, percentage of successful eggs, or both. Nolan (1963) noted that when only nest success is calculated, a nest whieh hatched only one egg received the same credit as a nest in whieh the entire clutch hatched. He felt that while this test was a fair indicator of predation, which normally results in all eggs being lost, it gave no measure of partial failure due to infertile eggs or embryonic mortality. Kalmbach (1939:592) stated: “Estimations on the basis of eggs hatched will regularly tend to diselose a lower degree of success than that based on so- called successful nests.” Nice (1957) found that for 18 studies she reviewed, the percentage of eggs which produced fledgling young was lower than the percentage of nests which produced at least one fledgling young; but, she noted that egg success could be higher if many nests containing incomplete clutches were deserted (or destroyed) and if all eggs hatched in most success- ful nests. Our findings, contrary to the above, revealed that the percentage of suc- cessful eggs was higher than nests. This mainly reflected the low number of unhatched eggs in successful nests and the large number of incomplete clutches destroyed by predators. Our data showed a significantly higher survival rate among nestlings than eggs; 42.1 per cent of all eggs laid were hatched while 80.3 per cent of all young hatched were fledged. Apparently, this is the normal situation in open- nesting, altricial birds; examination of 26 studies (Nice, 1957 :306-307) showed survival to be higher among young than eggs in 20 cases, lower in 5, and the same in 1. Using 18.5 days as the average length of time eggs occupy the nest ( including laying) and 11.5 days as the average period young are in the nest, total losses of eggs averaged 3.1 per cent per day while losses of young aver- Koseberry and Klimstra MEADOWLARK NESTING ECOLOGY 259 Causes of Nest, Egg, and Table 6 Nestling Losses for Meadowlarks, Southern Illinois Nests Eggsi Young' Factor No. Per cent of lost nests Per cent of all nests No. Per cent Per cent of lost of all eggs eggs No. Per cent Per cent of lost of all young young Human disturbance 3 1.7 1.1 6 1.8 1.0 0 0.0 0.0 Abandoned 11 6.0 4.2 13 3.9 2.3 0 0.0 0.0 Destroyed by livestock 2 1.1 0.8 4 1.2 0.7 0 0.0 0.0 Destroyed by mowing 32 17.6 12.2 64 19.1 11.1 0 0.0 0.0 Predation 134- 73.6 51.2 226 67.7 39.2 46 95.8 18.9 Infertile eggs — — — 7 2.1 1.2 — — — Embryo mortality — — — 4 1.2 0.7 — — ■ — Disappeared^ — — — 10 3.0 1.7 2 4.2 0.8 Totals 182 100.0 69.5 334 100.0 57.9 48 100.0 19.7 1 Based on observation of 170 nests. - Eighteen of these were destroyed after hatching but prior to fledging. ^ No obvious sign of disturbance and nest not completely emptied. aged 1.7 per cent per day. These average daily losses are not comparable to Nice’s figures (1964) for the Song Sparrow, for she calculated the percentage of young lost by dividing the number lost by the number of eggs laid instead of dividing (as we did) the former number by the number of eggs hatched. Several reasons for the higher survival of nestlings on our study areas are readily apparent. Infertility and embryonic mortality naturally affect only eggs, and desertion by the female occurs much more frequently (if not exclu- sively) before the eggs have hatched. Losses to mowing were rather high among eggs but did not affect young, although this must surely have been a matter of chance and timing as nests in all stages would be equally susceptible to this type of destruction. Losses to predators were more equal among eggs (2.1 per cent per day) and young (1.6 per cent per day) but still 1.3 times greater for the former if the relative time each was exposed to this hazard is taken into account. It is possible that nests containing eggs are more readily found by predators (eggs are somewhat more easily seen by humans than are the young), hut we have no data to substantiate this. Rather, il is jfiobahle that those nests which are most vulnerable to predation ( poorly concealed or located near hunting trails) would be found and destroyed sometime during the first 18 or so days before the eggs have hatched. Gonversely, if nests sur- vive this period without being preyed upon, it probably reflects optimum cover and concealment, hence a greater likelihood of remaining undetected through- out the remainder of their use. 260 THE WILSON BULLETIN September 1970 VoL 82, No. 3 Causes of Nest Failures Ahandonment. — Of 262 nests with eggs, 14 were abandoned by the female; a total representing 5.3 per cent of all nests and 7.7 per cent of all nest failures (Table 6). Saunders (1932) found that, occasionally, females deserted their nestlings; this was not observed in our study as all desertions occurred before the eggs hatched. Three nests were abandoned after having been slightly dam- aged by research workers; to our knowledge no other desertions were caused by human interference. Incubating females readily flushed from the nest upon approach but usually flew only a few feet off the ground and alighted within 20-30 yards of the nest. Some females were flushed as many as four times during the nesting cycle without causing desertion. At one extremely open nest site (in a mowed field) the senior author observed a female flush off the nest, fly a short distance, then land and run along the ground using the broken wing ruse. Almost immediately a male, which had been perched in a small shrub about 12 yards from the nest, alighted and began running from the nest at a 30° angle from the retreating female’s path. He did not feign injury but moved slowly and stayed just ahead of the observer. In addition to the three nest abandonments caused by human interference, 11 instances of abandonment from other causes were recorded during the study; at least two and possibly more of these were evidently due to parasitism by the Brown-headed Cowbird {Molothrus ater) . Two nests each containing two eggs thought to be those of the cowbird were found; in one, a meadowlark egg was lying undamaged just outside the nest entrance. None of these cow- bird eggs hatched, having apparently not been incubated. Of the remaining nine abandoned nests, four had single eggs lying just outside the nest, three contained a single egg in the nest, one had two eggs in the nest, and one had three eggs in the nest and one outside the entrance. Friedmann (1963) and Gross {in Bent, 1958) believed the Eastern Meadow- lark to be an uncommon host of the Brown-headed Cowbird. Saunders ( 1932 ) in a study of over 50 nests from New York and Oklahoma found no evidence of cowbird parasitism and Terrill (1961) reported only 1 of 52 nests para- sitized in southern Quebec. Other workers, however, have noted more exten- sive use of meadowlark nests by cowbirds. In Wisconsin, Lanyon (1957) found cowbird eggs in 9 of 41 (22 per cent) S. neglecta nests and 6 of 38 (16 per cent) S. magna nests. In Nebraska, Hergenrader (1962) reported 5 of 31 ( 16 per cent) S. magna nests parasitized. Eifrig (1915 and 1919) wrote that he “repeatedly” found meadowlark nests containing cowbird eggs in the Chi- cago region. Bobwhite eggs have also been found in meadowlark nests (Lackey, 1913) ; however, this apparently is uncommon and does not constitute nest parasitism K osebcrry ami Kliinstra MEADOWLARK NESTING ECOLOGY 261 (Gross m Bent, 1958). On 29 May 1967, a female meadowlark was flushed from a nest containing five meadowlark and three quail eggs. On 6 June, the nest contained one newly hatched meadowlark along with the remaining uii- disturbed eggs; on 7 June, two meadowlarks had hatched with the quail eggs still present. The nest was revisited on 13 June and while it showed no sign of damage, all young and eggs were gone; they were believed removed by a snake. Mowing and livestock. — Gross (m Bent, 1958:75) wrote: “. . . it is prob- ably safe to state that more meadowlarks [nests] are destroyed by this means [mowing] . . . than by any other.” Losses inflicted by mowing operations dur- ing our study were relatively high but did not constitute the major source of nest destruction. Thirty-two nests were destroyed in this manner, a total rep- resenting 12.2 per cent of all nests and 17.6 per cent of all nest losses (Table 6). Twenty-two of these resulted from hay cutting, 7 from pasture mowing, 1 from wheat combining, and 2 from miscellaneous mowing. Only one female was killed at the nest by a mower. Probably the tendency of birds to readily flush upon approach accounts for this low figure. Although 120 nests were located in areas grazed by livestock, only 2 were destroyed by trampling. During a 3-year period, Lanyon (1957) found 122 nests on 100 acres of permanent pasture on which 40-50 head of cattle grazed. He reported a loss due to cattle of 15 nests or 12.3 per cent of all nests and 18.8 per cent of all nest losses. Predation. — Losses attributed to predation during our study amounted to 51.2 per cent of the nests (73.6 per cent of nest failures) and 47.1 per cent of the eggs and young (67.7 per cent of all egg losses and 95.8 per cent of all nestling losses ) . This is somewhat higher than the relative and total predation reported by Lanyon (1957) in Wisconsin; he found that 36.1 per cent of all nests were preyed upon and 55.0 per cent of all nest losses were due to preda- tion. Because they are always located at ground level, meadowlark nests are sub- ject to predation by a variety of animals. Gross [in Bent, 1958) thought that domestic dogs and cats were especially destructive to nests located in fields adjacent to farm houses. Lanyon (1957) attributed most of the predation ob- served on his Wisconsin study area to the red fox [Vulpes vulpes) and do- mestic dog and cat, with skunks [Mephitis mephitis), thirteen-lined ground squirrels [Citellus tridecemlineatus) , and garter snakes [Thamnophis sirtalis) also contributing. Saunders (1932) felt that the house cat was the most serious predator although weasels (Mustela erminea), skunks, and dogs also preyed upon nests. He suspected meadow mice ( Microtus pennsyJvanicus ) and Gom- mon Grows iCorvus brachyrhynchos) as occasional destroyers of eggs. 262 THE WILSON BULLETIN Sepleniber 1970 Vol. 82, No. 3 I he difficulty of assigning responsibility of individual nest destruction to specific predators has already been discussed. Of the 134 instances of preda- tion on our study area, the precise predator involved was unknown in 100 cases. Of the remaining 34, 13 were attributed to snakes, 9 to house cats, 6 to skunks, 5 to foxes or dogs, and 1 to an avian predator. These data are mis- leading, however, for they imply that snakes were the most serious predators, when in fact, most of the 100 unknowns were mammals of one species or another. As previously noted, the survival rate of nests and eggs was quite low on Bigler’s pasture. Here, losses to predators amounted to 72.2 per cent of all nests and 87.5 per cent of all nest failures, as compared to 38.8 per cent and 62.7 per cent, respectively, for the remainder of the area. Similarly, nesting Bobwhite also suffered unusually heavy losses in this field during the same period (Klimstra, unpublished data). Lrom 1954 through 1965, Bobwhite nest losses to predation amounted to 35.2 per cent on all areas other than Big- ler’s pasture. Lrom 1954 through 1963, on Bigler’s, Bobwhite suffered a 41.8 per cent loss to predators, but during the 2 years (1964 and 1965 ) when the field was not grazed and meadowlark nest density was highest, predators de- stroyed 24 of 29 quail nests (82.8 per cent ) located in the field. No detailed surveys were made of the kinds and numbers of predators pres- ent in this area. Nevertheless, routine observations in the course of nest hunt- ing activities clearly indicated that this particular field served as hunting ter- ritory for an unusually large number of carnivores, especially during 1964 and 1965. Ten houses were located within 14 mile of the field; five within 100 yards. At least six dogs were known to roam the field; house cats, while seen much less frequently, also hunted the area. While not thought overly abun- dant, red foxes, and possibly some gray foxes [ Urocyon cinereoargenleus) , were also present as evidenced by scat and sign. A 3.8-acre pond in the center of the field also attracted raccoons {Procyon lotor) and opossums (Didelphis marsupialis) . Snakes were quite common; blue racers [Coluber constrictor) and prairie kingsnakes { Lanipropeltis caligaster) were noted with regularity during the nest hunts. By far the most common carnivore, however, seemed to be the striped skunk. Numerous dens were located in and around a 4-acre woodlot near the center of the field while diggings and trails were numerous throughout the area. Lrequently, skunks were seen in the field in daylight; as many as three different animals were observed in one morning. In addition to predators, there appeared to be an extremely high population of prairie voles [Microtus ochrogaster) . Runways and grass nests seemed uni- formly abundant throughout the field and numerous voles were seen as we searched the ground for nests. It is our contention that instead of actina as Kosebcrry and K1 imstra MEADOWLARK NESTING ECOLOGY 263 buffers, these rodents actually attracted predators to the area and held thein for longer periods of time by making their hunting efforts more profitable. Because the finding of stationary and concealed nests is more or less a matter of chance, the percentage of these nests found must invariably increase iii direct proportion to the number of “predator-hours” spent in the field. Stod- dard ( 1931 ) also felt that high populations of rodents (cotton rats, Sigtnodon hispidus) attracted predators which, once in the area, found and destroyed quail nests. Infertile eggs and embryonic mortality. — Data concerning unhatched eggs in successful clutches were obtained from 63 nests which were under observa- tion before and after hatcbing. Of 264 eggs in these nests, 7 ( 2.7 per cent ) failed to hatch because of infertility, 4 (1.5 per cent) because of embryonic mortality, and 10 unaccountably disappeared (possibly removed by the fe- male). Thus, total loss from non-hatched eggs amounted to 8.0 per cent. Saunders ( 1932 ) , who suspected that the production of infertile eggs might be related to old age and highly nervous temperament of the laying female, found 14 ( 16.5 per cent ) of 85 eggs observed to be infertile. The much higher per- centage of infertile eggs in his study as compared to ours cannot at present be explained. Factors Affecting Nest Success and Losses Degree of nest construction. — Thinly- or non-roofed nests (61.8 per cent), in which the eggs were in some measure visible from above, suffered a 57.4 per cent loss to predation and were 33.1 per cent successful as compared to a 51.2 per cent loss and 38.1 per cent success for fully roofed nests. While not statistically significant (P = 0.30), these data at least suggest the possibility of greater risk of predation when eggs are visible from above. A further breakdown of these data show losses from predation to have been 60.5 per cent for open nests, 56.1 per cent for partially roofed nests, and 51.2 per cent for fully roofed nests. Collias (1964) believed that the roofed nest, which probably evolved from a type that was open above, not only made predation less likely but also af- forded cooler temperatures and protection from rain. Our data relevant to protection from heat and rain are too few to warrant discussion. However, the history of one open nest suggests the hardiness of eggs and young. Five birds successfully fledged from this unroofed nest which was located in vegeta- tion less than 6 inches high. During the period when eggs were being laid and incubated, three daily rainfalls of 1.00, 0.58, and 0.11 inches were recorded; maximum air temperatures were 95 °F or above on 6 days with a high of 97°. In the 12 days during which the young occupied the nest, three rainfalls 264 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 amounted to 1.38, 0.13, and 1.17 inches; temperatures were 90° or above on 6 days with a high of 96° recorded on 2 days. Time of season. — Lanyon (1957), working with S. magna and S. neglecta in Wisconsin, reported a nesting success of 25.6 per cent for 86 nests of both species built during May and June and a 55.5 per cent success for 36 nests built during July and August. He suggested that higher nesting success during the latter part of the breeding season possibly reflected an increase in pro- tective cover. Data from our study also suggested an increase in nesting success as the season progressed. For comparative purposes, the season was divided into three parts: 14 April— 26 May, 27 May— 16 June, and 17 June-23 July. The per cent success of nests beginning in the above respective periods were 34.2, 37.9, and 55.6, while the percentages of nests destroyed by predators were 47.4, 43.9, and 27.8. Chi square in an r X 2 contingency table was used to test whether the ratios of successful to preyed upon nests varied with the time of season. The value obtained (4.35) approached significance at the 10 per cent level. Nest losses attributable to causes other than predation (abandonment, mowing, etc.) remained fairly constant throughout the three periods at 18.4, 18.2, and 16.6 per cent, respectively. Nolan (1963), analyzing the nesting success of 11 species of passeriformes, found that nest success increased significantly as the season progressed. He dismissed weather and nest abandonment as causes and stated: “. . . the ris- ing rate of suecess as summer advances must presumably be attributed to some combination of differences in the activities, diets, numbers, or species of predators.” As discussed earlier, skunks, house cats, dogs, and snakes were thought to have been the primary destroyers of meadowlark nests during our study. While no records were kept of their seasonal abundance and activities, some patterns were apparent from general observations. It is doubtful that the hunting habits of domestic dogs and cats varied greatly during the course of the nesting season. Snakes, on the other hand, were seen with increasing frequency during May, becoming progressively more scarce in June and July. This agrees with the observations of Klimstra (1958) in Davis County, Iowa. Conversely, skunks would logically be more numerous and active later in the season. Young skunks begin to hunt with the female at about 2 months of age, that is, sometime in July. Verts (1967) noted that female skunks were afield less during pregnancy and after it up to the time the young were about 1 month old; at that time (around 7-15 June), they resumed more or less normal nightly hunting patterns. Thus, observations of predator activities (with the exception of snakes) give no indication as to why predation should Roseberry and Klimstra MEADOWLARK NESTING ECOLOGY 265 be heavier early in the nesting season. In fact, contradictory evidence is available from Bobwhite nests located on the Research Area; these nests suffer significantly heavier losses to predators as the season progresses (Klimstra, unpublished data). At present, we have no explanation for these seemingly incompatible findings; there is nothing to suggest that Bohwhites and meadowlarks do not suffer nest losses from the various predators in relatively similar proportions. The whole problem of seasonal variation in nesting success is in need of further study. Land-use types. — As already discussed, nests located on Bigler’s pasture received unusually heavy losses from predation and, as this was thought to represent a special situation, the present section will deal only with nests located on other parts of the area. Nests in hayfields had the lowest rate of success (25.7 per cent) ; primarily this reflected losses to mowing (62.9 per cent } . Nests in idle and fallow areas showed 29.6 per cent success with 63.0 per cent being destroyed by predators. Nests in pasture and soilbank fields had a success of 42.9 per cent and 50.0 per cent, respectively, while suffering losses to predation of 42.9 per cent and 45.0 per cent, respectively. Of the four nests located in wheat fields, three (75 per eent) were successful; how- ever, the smallness of the sample prohibits concluding that these areas were relatively safer than others. The rate of abandonment was similar for all types of areas; 2.9 per cent in hayfields, 5.7 per cent in pastures, 5.0 per cent in soilbank fields, and 3.7 per cent in idle and fallow areas. SUMMARY From 1960 to 1967, 450 nests of the Eastern Meadowlark were found in the vicinity of Carbondale, Illinois. All nests were located at ground level and most were in cover 10 to 20 inches high; 17.3 per cent were open from above, 44.5 per cent were partially roofed, and 38.2 per cent had full canopies. The rush Juncus, meadow fescue, cheat, and bluegrass were most commonly used in nest construction. Almost 49 per cent of all nests faced in a general northeasterly direction. Earliest date of egg laying was 14 April, the latest 23 July; peak egg laying occurred from 22 April to 12 May. Pastures showed the highest nest density per 100 acres with an average of 20.9, followed by hayfields 12.6, soilbank fields 5.1, wheat fields 4.8, idle areas 3.8, and fallow fields 2.0. Average size of 101 complete clutches was 4.16 (range 2-6) ; number of eggs tended to decrease as the season progressed. Overall hatching success of 262 nests was 37.4 per cent; fledging success was 30.5 per cent. Predation (51.2 per cent) and mowing (12.2 per cent) were the primary destructive agents of nests. Extremely heavy losses to predators (72.2 per cent of 97 nests) in one field was discussed in detail. There appeared to be a direct relationship between degree of nest construction (amount of overhead protection) and nest success. The percentage of successful nests also increased as the season progressed. 266 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 ACKNOWLEDGMENTS Thanks are due to the many graduate research assistants and undergraduate workers of the Cooperative Wildlife Research Laboratory for their help in the arduous task of nest hunting. Special thanks go to Dave Rose, Richard Bartholomew, William Allen, and Max Hutchison who, at various times throughout the study, were in charge of field ci'ews. We are indebted also to Drs. William George and Wesley E. Lanyon for reading the manuscript and offering helpful comments and criticisms. This represents a con- tribution from Project No. 49, Cooperative Wildlife Research Laboratory, Southern Illinois University. LITERATURE CITED Bendike, C. E. 1895. Life histories of North American birds. U. S. Natl. Mus. Spec. Bull. 3. Bent, A. C. 1958. Life histories of North American blackbirds, orioles, tanagers, and allies. U. S. Natl. Mus. Bulk, 211:53-80. CoLLiAS, N. E. 1964. The evolution of nests and nest-building in birds. Amer. Zook, 4:175-190. D.wis, D. E. 1955. Breeding biology of birds, hi Recent studies in avian biology. A. Wolfson, (Ed.). Univ. Illinois Press, Urbana. Eifrig, C. W. G. 1915. Field notes from the Chicago area. Wilson Bulk, 27:417-419. Eifrig, C. W. G. 1919. Notes on birds of the Chicago area and its immediate vicinity. Auk, 36:512-524. Friedmann, H. 1963. Host relations of the parasitic cowbirds. U. S. Natl. Mus. Bulk, 233. Hann, H. W. 1937. Life history of the Ovenbird in southern Michigan. Wilson Bulk, 49:145-237. Hergenrader, G. L. 1962. The incidence of nest parasitism liy the Brown-headed Cowbird (Molothrus ater) on roadside nesting birds in Nebraska. Auk, 79:85-88. Johnston, R. F. 1964. The breeding birds of Kansas. Univ. Kansas Pulik Mus. Nat. Hist., 12:575-655. Kalmbacii, E. R. 1939. Nesting success: its significance in waterfowl reproduction. Trans. N. Amer. Wild!. Conf., 4:591-604. Klimstra, W. D. 1958. Some observations on snake activities and populations. Ecol- ogy, 39:232-239. Lack, D. 1954. The natural regulation of animal numliers. Oxford Univ. Press, London. Lackey, J. B. 1913. Notes from Mississippi. Oologist, 30:257-258. Lanyon, W. E. 1957. The comparative biology of the meadowlarks (Starnella) in Wisconsin. Pubk Nuttall Ornithok Club, 1. Mayfield, H. 1960. The Kirtland’s Warbler. Cranbrook Inst. Sci., Bulk 40. Mayfield, H. 1961. Nesting success calculated from exposure. Wilson Bulk, 73: 255-261. Nice, M. M. 1957. Nesting success in altricial birds. Auk, 74:305-321. Nice, M. M. 1964. Studies in the life history of the Song Sparrow. Vol. 1. A popu- lation study of the Song Sparrow. Dover Pubk Inc., New York. Nolan, V., Jr. 1963. Reproductive success of birds in a deciduous scrub habitat. Ecology, 44:305-313. Reed, C. A. 1965. North American birds eggs (Revised Ed.). Dover Pubk Inc., New York. Uoseberry and Klimstra MEADOWLARK NESTING ECOLOGY 267 Sandborn, C. C., and W. A. Goelitz. 1915. A two year nesting record in Lake County, 111. Wilson Bull., 27:434-448. Saunders, G. B. 1932. A taxonomic revision of the meadowlarks of the genus Sturnella (Vieillot) and natural history of the Eastern Meadowlark, Sturnella rnagna magna (Linnaeus). (Ph.D. thesis, Cornell Univ.). Stoddard, H. I,. 1931. The Bohwhite Quail; its hahits, preservation and increase. Chas. Scribner’s Sons, New York. Terrill, L. M. 1961. Cowbird hosts in southern Quebec. Canadian Field-Naturalist, 75:2-11. Thoms, C. S. 1924. The Eastern and Western meadowlarks. Bird Lore, 26:315-317. Verts, B. J. 1967. The biology of the striped skunk. Univ. Illinois Press, Urhana. COOPERATIVE WILDLIFE RESEARCH LABORATORY, SOUTHERN ILLINOIS UNIVER- SITY, CARBONDALE, ILLINOIS, 6 JANUARY 1968. NEW LIEE MEMBER Ralph W. Schreilier, a graduate student at Florida Southern University, has recently become a Life Member of the Wilson Society. Mr. Schreiher holds degrees from Ihe College of Wooster, and The University of Maine. His major ornithological interest is the behavior-ecology of seabirds. His work on the Herring Cull was supported by a Louis Agassiz Fuertes Grant in 1966. Mr. Schreiher is a member of the AOU, the BOU, the Cooper Ornithological Society, and other scientific organizations. DOMINANCE-SUBORDINATION IN CAGED GROUPS OF HOUSE SPARROWS John R. Watson Ornithologists long have been intrigued with the behavioral mechanisms which tend to promote gregariousness and precision of flock activities (Emlen, 1952; Moynihan, 1960; Crook, 1961). Dominance-subordination relationships in gregarious species have been studied by a number of workers (Masure and Alice, 1934; Shoemaker, 1939; Ritchey, 1951; Sabine, 1959; Thompson, 1960; and Ellis, 1966) to name but a few. The behavioral mechanisms operating in the maintenance of gregariousness in the House Sparrow {Passer domesticus) have received little attention. The possibility that dominant individuals act to synchronize group activities in large foraging flocks of House Sparrows was suggested by Summers-Smith (1963). Some aggressive characters in a flock of color-marked House Spar- rows were studied by Simmons (1954) but he made no statements on the domi- nance structure of the flock. Since this species occurs commonly in large flocks, observations of domi- nance-subordination relations and behavioral cycles are made difficult by the diversity of flock activities. However, if a dominance structure exists, it should be evident in small flocks subjected to intensive study. Accordingly, groups of House Sparrows were assembled in order to study the various aspects of domi- nance-subordination under captive conditions. METHODS Eight groups of House Sparrows totaling 52 individuals were taken at various locations in and around Logan, Utah, between January and September, 1965. The groups contained 8, 8, 4, 6, 6, 8, 6, and 6 individuals, respectively. No more than two individuals of any group were taken from any one locality, thus minimizing the influence of previous inter- actions. Excepting one group (Table 2), no individual was used in more than one experi- ment. Members of each group were individually color marked and released into the aviary simultaneously. Two separate, visually isolated aviaries measuring 9 X 7 X 10 feet were utilized in the study. Constant 12-hour photoperiods were maintained through the use of an automatic light timer installed after April, 1965. Observations were made through tinted glass. Each aviary was supplied with a perch graduated at one-inch intervals, a simulated tree perch, a water can, and a large floor feeder (a wooden tray, 18 X 36 inches). Millet was provided ad libitum and meal worms (Tenebrio) were occasionally used. The observation periods were rotated daily on a systematic basis (“morning,” “after- noon,” and “evening”) in order to compensate for cyclic behavior fluctuations. Both first-year and juvenile birds were included in this study (Table 1, groups 3, 4, 6, 268 John R. Watson DOMINANCE-SUBORDINATION IN SPARROWS 269 E9 Fig. 1. Relative dominance between four classes of House Sparrows. Cross-hatching in- dicates the percentage of encounters won. For example, first-year birds were dominant to adult females in 85 per cent of the contests. Based on the dominance-subordination data from groups 1-7 (Table 1). Key: AM — Alpha Male; F — Adult Female; M — Adult Male; FY — First-Year (A composite of first-year and juvenile birds). and 7). First-year birds are those which completed the post-juvenal molt and still show incomplete skull ossification. However, I will refer to both age classes as first-year birds; exact designation will be given in the tables. Social ranking was determined through dominance and subordination responses (i.e., supplanting by the dominant bird and subsequent withdrawal by the submissive) at the feeder, water can, and perches. Threat displays resulting in spacing were not recorded as a “win” or “loss.” Dominance and subordination were tested using the chi-square test with a 2 X t contingency table (Ostle, 1963). The correction for continuity was used on 2x2 tables. The percentages of wins were compared for each bird in each group. Additional information was obtained by observing free-living flocks of House Sparrows at two locations outside Logan, Utah, from March, 1965, through September, 1965. One flock numbering around 100 individuals contained 37 marked birds. RESULTS Dominance and subordination.- — -The general pattern of interactions is shown in Figure 1. Each group under observation included a dominant adult male (Tables 1-2). Although no straight-line social rank system was present, I will refer to the individual having the highest number of wins as the alpha male. Due to the presence of this more combative bird (see beyond), all groups were highly significant (99 per cent level) with respect to the percentages of wins. Analysis showed significant differences (95 per cent level) between this more combative bird and other flock members. Three exceptions occurred (Table 1, groups 3 and 4; Table 2, 8b, 8c, and 8e) . Groups 3 and 4 (Table 1) included first-year birds. First -year males secured high percentages of wins through successful encounters with the alpha male (Figure 1, Table 4). Sim- mons (1954) stated that he found “juvenile” House Sparrows to be regularly very pugnacious over food, holding their own not only with adult House Spar- rows but sometimes against Starlings (Stiirnus vulgaris). Similarly, Thompson 270 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 1 The Percentages of Wins of 7 Groups of Captive House Sparrows Groups Alirha Male Male Male Male Female Female Female Female 1 2-29 January 1965 Per cent 85 41* 14* 9* 64* 67* 33* 16* of Wins (843) (285)1 (319) (282) (160) (135) (151) (153) 2 6-19 February 1965 Per cent 92 14* 34* 24* 50* 52* 33* 49* of Wins (472) (367) (121) (144) ■ (70) (48) (57) (35) 3 1-20 April 1965 fy2 sfy2 Per cent 93 38* 11* 67* 56* 17* — - — of Wins (378) (164) (372) (30) (36) (12) — — 4 7-22 May 1965 fy“ Per cent 87 15* 32* 64 20* 8* — — of Wins (198) (124) (66) (58) (35) (39) — — 5 9 June-6 July 1965 Per cent 83 11* 41* 36* 34* 40* 40* 29* of Wins (551) (311) (169) (100) (86) (62) (60) (21) 6 30 July-18 August 1965 juv^ Per cent 84 44* 12* 56* 20* 4* — — of Wins (306) (122) (177) (104) (49) (46) — — 7 11 September-4 October 1965 juv^ Per cent 82 30* 40* 94 15* 69* — — of Wins (319) (233) (154) (137) (59) (118) — — 1 Number in parentheses is the size of sample. 2 fy = first year; sfy = suspected first year; juv = juvenile. * Significant differences from Alpha Male ( 0.95 level ) . (1960) stated that in the wild, “juvenile” House Linches {Carpodacus mexi- caniLs) often won encounters over adults of the same species. Inspection of groups 3 and 4, and 7 shows high percentages of wins for the first-year birds relative to the alpha male. However, marked differences occur when one com- pares the total number of encounters between the two birds (alpha and first- year). Therefore, regardless of this result, the alpha male was still the more combative bird. JollM K. Watson DOMINANCE-SUBORDINATION IN SPARROWS 271 Table 2 Cumulative Percentage of Wins of 2 Groups of Captive House Sparrow's Groups Male (A) Male (B) Male (C) Male (D) 8a. 23-28 April 1965 Percentage of wins 76* 24** • — • — 8b. First two hour observation period, 29 April 1965, males C and D are from group three (Table 1) having previous win-loss ratios of 0.9259 and 0.1129 respectively. Percentage of wins 92* 100 4** 0** 8c. Second two hour observation period on 30 April 1965 Percentage of wins 69 100 50 0 8d. Third two hour observation period on 1 May 1965 Percentage of wins 23** 0** 96* 0** 8e. Fourth hour observation period on 2 May 1965 Percentage of wins 25** 100 76* 0** * Denotes alpha male. ** Significant difference from alpha male (0.95 level). Characteristically, the alpha male initiated the aggression against the first- year birds. Once attacked, the first-year males — and in one case a suspected first-year female (Table 1, group 3; Table 3) — demonstrated marked abilities of self-defense, often assuming the hen threat posture illustrated by Summers- Smith (1963, Fig. 2). The first-year birds never pressed the attack, but merely refused to leave their positions even if actual fighting contact occurred. Simi- lar behavior occurs in Blue Tits [Parus caeruleus) in which feeding birds show a tendency to stay and threaten intruders in lieu of overt attack ( Stokes, 1962) . Uinta ground squirrels {Cilellus armatus) involved in maintenance activities also demonstrated this “stay threat” behavior (Balph and Stokes, 1963) . “Stay threat” behavior was more pronounced in juvenile ground squir- rels than adults (Balph, personal communication). Also, “stay threat” response was more intensely displayed by first-year House Sparrows than by adults of the same species. The alpha male defended the simulated tree perch, the marked perch, and the elevated water can. At night the remaining males were forced to use the floor or to cling to the tiled ledges for perch (roost) sites. The females and first-year birds generally roosted on the floor but sometimes they remained on the elevated perches with the alpha male. Examination of Tables 3 and 4 shows the alpha male directing a great num- ber of attacks toward one specific adult male. This male maintained no spe- 272 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 3 Individual Encounter Data from the April Group (Table 1, Group 3) Bird Alpha Male A Male B Male C First Year Male D First Year Female Female E F A 66 Loss 268 4 10 2 B 6 56 0 0 0 C 0 34 4 2 2 Win D 6 2 2 4 6 E 14 0 4 2 0 F 2 0 0 0 0 cific site and thus was subject to constant attacks from the alpha male. The remaining adult males secured isolated sites at which they remained (unless feeding or drinking), and which they actively defended. These sites were not associated with any perching device in the aviary but were situated in the far left corner (from entrance) of the aviary 75 inches from the floor level on a ledge atop the tiled portion of the wall. The adjacent right corner was only 6 inches from the elevated perch and hence was defended by the alpha male. At these specific sites, the alpha male was subordinate. In groups 1, 2, and 5 (Table 1) the site problem was more acute due to the presence of four adult males. In each of these groups, an adult male remained on the wall thermostat which was situated only two feet from the elevated perch. This position offered some protection from the alpha male and usu- Table 4 Individual Encounter Data from the August Group (Table 1, Group 6) Bird Alpha Male A Male B Male C First Year Male D First Year Female E Female F A 56 Loss 140 24 22 14 B 22 6 10 10 6 C 2 8 4 0 8 Win D 26 4 9 8 9 E 0 0 0 0 2 F 0 0 2 4 4 John R. Watson DOMINANCE-SUBORDINATION IN SPARROWS 273 ally ensured its occupant of an elevated roost overnight. Again, the male re- ceiving the majority of defeats had no specific site to defend. The flocks tended to remain in only one half of the aviary even though perching devices were placed at the opposite end. The area in which the flocks remained contained the food and water trays. Birds flying to the far end of the aviary were quick to return to the flock. Similar behavior was reported for Quelea quelea by Crook (1961). The subordinate males did not utilize the far corners for roost sites. Seemingly, the attraction of the group had priority over the effects of subordination. Status of females and first-year birds. — As shown in Figure 1, adult fe- males were subordinate to the other classes of sparrows. This was due, in part, to their tendency of readily submitting to aggression on the perches. The fe- males initiated few direct agonistic encounters. Their fights per hour averaged 1.3, whereas adult males averaged 8.2 fights per hour. This last figure is somewhat distorted, however, due to the activity of the alpha male. Normally, males would not attack females unless they crowded too close on the perches or in the feeder. Attacks upon females by males were of low intensity and rarely included physical contact. Many times the females would merely space out, this action being sufficient to halt the male aggression. However, adult females were dominant over adult males in 44 per cent of the encounters (Fig. 1 ) . In contrast, male attacks upon males invariably necessitated one or the other leaving the immediate site. The first-year birds tended to remain with the adult females and were treated as females by adults of both sexes. The alpha male characteristically made direct, sudden attacks upon the adult males with little preliminary display given. However, his attacks upon females and first-year birds were of a threat nature, followed by direct attack only if the recipient failed to respond by moving away or by showing submissive be- havior. Because they had not yet completed the post-juvenal molt, the juveniles (Table 1, groups 6 and 7) closely resembled the adult females in appearance and (as indicated above) were treated as adult females. This similarity of juvenal plumage to that of advanced first-year or adult female House Sparrows has been described by Selander and Johnston (1967). The two first-year males (Table 1, groups 3 and 4) showed a variable amount of white tipping to the black chin feathers, and the pileum had a brownish hue, rather than gray of the adult male. As stated previously, “stay threat” behavior was characteristic of both juve- nile and first-year birds. The results of “stay threat” are reflected in the high win success as indicated in Figure 1. This pugnacity seems functional, for these young birds can defend against intruding adult males while feeding and 274 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 perching. These early aggressive encounters undoubtedly contribute to the fitness of young birds by providing valuable fighting experience prior to their first breeding season. Manipulation of birds. — One experiment was conducted with two males designated A and B, respectively. A was dominant over B (Table 2, oa) having 59 wins to 19 wins for B. On 20 April 1965, I released two birds from the April group, the alpha male designated C and a subordinate male designated D ( Table 1, group 3) with A and B. During the first two hours of observa- tion, A defeated C 94 times, illustrating how familiarity with an area can influence the outcome of aggressive encounters. Similar results were reported for caged groups of House Linches by Thompson (1960) . D, who had lost all previous encounters with C, was successful in defeating C 19 times on the perches. Two factors seemed to be involved. When the alpha male would rapidly displace one individual about the aviary, others might also join in and displace the recipient. The recipient, under these conditions, would readily give way to any aggression directed towards him. There seemed to be an “aggressive momentum” operating first in the attack by the alpha bird, and subsequently spreading to the other flock members. Correlated with this was a tendency towards heightened submission by the bird subjected to these rapid attacks. Another factor was that C, who previously had maintained a large defended area, now was without one in strange territory. On the third day, C was ahead of A with percentages of 96 and 23, respec- tively, indicating a reversal of dominance (Table 2, 8d). This relationship held until the sixth day, when A was discovered dead. Flock activities. — Within certain limitations, synchronization and integra- tion within the flocks followed an intrasexual pattern. However, the first-year birds tended to remain with the adult females and were treated as females by adults of both sexes. Ligure 2 represents a sample recording of group activity cycles from a well-stabilized flock at four times over the course of one photo- period. The figures show that the individuals tended to be engaged in the same activities at the same time, much as shown for Qiielea quelea by Crook (1961). Despite uniformity of photoperiod (constant 12 hr) and temperature, a definite daily activity pattern was present. Ligure 2 illustrates this phenome- non. The greatest amount of active behavior (e.g., feeding) occurred in “morning” and “evening” periods, whereas the “afternoon” period was char- acterized by drowsiness with much sitting and occasional feeding. These pat- terns resembled those described by Beer (1961) for free-living winter flocks of House Sparrows. The last half-hour of light was one of great vocal and ag- gressive activity resembling natural pre-roosting behavior. Although these be- Jolin R. Watson DOMINANCE-SUBORDINATION IN SPARROWS 275 Fig. 2. Recording of group activity cycle of House Sparrows from the June-July flock (Table 2, group 5). Six birds observed for 60 minutes from 07:00-08:00. (A). 10:30- 11:30. tB), 13:30-14:30. (C), 17:00-18:00. (D). Observations were made at the begin- ning of each three minute period. Key: Feeding — Small dots; Hopping — Horizontal bars; Flying — Vertical bars; Sitting — Large dots; Feather care — Cross bars. havioral adjustments were made under artificial conditions, they served to es- tablish a cyclic context from which observations could be interpreted. As stated by Moynihan and Hall (1953), the motivation of a specific behavior pattern was considered to be the same, whether performed in a cage or in the wild. In these experiments, the alpha male showed a marked tendency to divorce himself from flock activities. This bird showed little tendency to follow others and no marked potential for initiating new flock activities. When not fighting, the alpha male could be identified by his behavior of sitting lethargically in one place and not participating in flock activities. Data from the April group (Table 2, 8a) showed A dominant over B. Out of 226 flights by A, individual B followed 158 times. Conversely, out of 606 flights by B, male A followed only 32 times. The greater number of flights by B was attributed to the great nervousness of the bird. In this case, the sub- 276 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 ordinate did follow the alpha male a significant number of times. However, this was probably the result of a small opportunity for alternate action coupled with the nervousness of B. Also, the passive behavior of the alpha male was a factor. In larger groups (N = 6 to 8 ) , all birds showed an equal potential for elicitation of new activities (based on qualitative notes). DISCUSSION The dominance-subordination relationships of highly gregarious species of birds have been subject to much speculation. Schjelderup-Ebbe (1933) stated that beyond 10 individuals, straightdine hierarchies rarely exist. Conversely, Guhl (1953) gave evidence for a hierarchy in a flock of 96 pullets. Sabine (1959) described a scale of dominance for a flock (that resulted from the amalgamation of two flocks) of 42 Oregon Juncos { Junco oreganus) . How- ever, it would seem that these flock sizes represent the extreme upper limits for individual meeting and acquaintance to occur. Whether the results of investigations using small numbers apply equally well to larger flocks was questioned by Banks and Allee ( 1957 ) . It seems reasonable, however, that if a hierarchy is nonexistent in small flocks one would not exist in larger flocks of the same species. No obvious linear hierarchy existed with the captive sparrows. Lor exam- ple, Table 3 (April group) indicates a peck rank for three adult males (A 66/72, B 6/72, C 0/268). The disproportionate defeats assumed by C were due to his lack of a defended site. However, B, who did maintain a specific site at which he remained, was largely free from attacks and managed to de- feat A 6 times at this location. Therefore, the situation revealed reversible site- related dominance among the males. Since the black bill color was lost by the captive males indicating gonadal regression (Keck, 1932) and no sexual dis- plays were seen, reproductive complications were minimized. Instances of caged birds establishing separate territories have been recorded for a few species (Shoemaker, 1939; Ritchey, 1951). In caged groups of House Linches, the alpha pair defended the entire aviary with the beta pair defending the same area but with less aggressiveness (Thompson, 1960). How- ever, Ellis (1966) showed a hierarchy independent of site relationships in cap- tive groups of Starlings. In my experiments, the alpha male exerted his influ- ence over the largest area somewhat resembling the behavior of the caged House Einch but the sparrow aggression was not related to pair nest defense, and the other male sparrows did not defend the same area. The situation seemed to agree with the findings of Ritchey (1951) who stated that in caged groups of domestic pigeons, a linear hierarchy was blocked by site-related dominance. John K. Watson DOMINANCE-SUBORDINATION IN SPARROWS 277 The results of this captive study may relate to certain events occurring un- der natural conditions. As stated by Dixon (1965), reversible, site-related responses between individuals have little value in promoting group unity. Free-living adult male sparrows maintain one specific site for both the breed- ing and non-breeding season (Summers-Smith, 1963). However, the intensity of intolerance exerted in defense of these sites during the non-breeding season is unclear. In any event, this type of site-related aggression would have ques- tionable significance in large flocks of foraging sparrows. When on neutral ground, an attacking sparrow seems to have the advantage over the recipient (notwithstanding “stay threat” behavior). This situation was apparent in the large floor feeder where aggression was rare. Reduced aggression at the feeder has also been reported for caged groups of Goldfinches {Spinus tristis) by Coutlee (1967). SUMMARY Dominance-sul)ordination relationships were studied in 8 groups (2-8 individuals per group) of captive House Sparrows between January and September, 1965. In each group a highly combative male won the majority of contests, but a linear hierarchy was blocked by reversible site-related dominance. The significance of site-related aggression in large flocks of foraging House Sparrows is questioned. The adult females rarely fought among themselves and were largely free from adult male aggression. First-year birds were treated as adult females by adults of both sexes. However, when attacked they demonstrated “stay threat” behavior. “Stay threat” was characterized Ijy the first-year birds actively defend- ing their positions when attacked without pressing the encounter beyond the immediate site. Activity patterns were greatest during “morning” and “evening” periods with a charac- teristic “mid-day lull.” The birds tended to engage in the same activities at the same time. The top-ranking adult male showed a tendency to divorce himself from the flock and demonstrated no marked potential for initiating new flock activities. ACKNOWLEDGMENTS I am indebted to Dr. Keith L. Dixon for his able guidance during the course of this study. Also I would like to thank Dr. Allen W. Stokes and Dr. Raymond T. Sanders for their helpful criticisms of the manuscript. In addition, my heartfelt thanks to Mr. James L. Woodson for his advice and timely discussion of the study. This report is based on a portion of a Master’s Thesis in the Department of Zoology, Utah State University. LITERATURE CITED Ralph, D. F., and A. W. Stokes. 1963. On the ethology of a population of Uinta Ground Squirrels. Amer. Midland Naturalist, 69:106-126. Banks, E. M., and W. C. Allee. 1957. Some relations Ijetween flock size and agonistic behavior in domestic hens. Physiol. Zook, 30:255-268. Beer, J. R. 1961. Winter feeding patterns in the House Sparrow. Auk, 78:63-71. Coutlee, E. L. 1967. Agonistic behavior in the American Goldfinch. Wilson Bull., 79: 89-109. 278 THE WILSON BULLETIN September 1970 Voi. 82, No. T Crook, J. H. 1961. The basis of flock organisation in birds. In Current Problems in Animal Behaviour. W. H. Thorpe and 0. L. Zangwill (Eds.), Cambridge Univ. Press, pp. 125-149. Dixon, K. L. 1965. Dominance-subordination relationships in Mountain Chickadees. Condor, 67:291-299. Ellis, C. R., Jr. 1966. Agonistic behavior in the male Starling. Wilson Bull., 78:208-224. Emlen, J. T., Jr. 1952. Elocking behavior in birds. Auk, 69:160-170. Guiil, a. M. 1953. Social behavior of the domestic fowl. Tech. Bull., Kansas Agri. Exp. Sta., No. 73:1-48. Keck, W. N. 1932. Control of the sex characters in the English Sparrow, Passer domes- ticus. Proc. Soc. Exp. Biol, and Med., 30:158-159. Masure, R. H., and W. C. Allee. 1934. The social order in flocks of the common chicken and pigeon. Auk, 51:306-327. Moyniiian, M. 1960. Some adaptations which help to promote gregariousness. Proc. XII Intern. Ornithol. Congr. :523-541. Moyniiian, M., and M. F. Hall. 1954. Hostile, sexual and other social behaviour patterns of the Spice Finch {Lonchura punctulata) in captivity. Behaviour, 7:33-76. OsTLE, B. 1963. Statistics in research. Iowa State Univ. Press. Ritchey, F. 1951. Dominance-subordination and territorial relationships in the com- mon pigeon. Physiol. Zook, 24:167-176. Sabine, W. S. 1959. The winter society of the Oregon Junco: intolerance, dominance, and the pecking order. Condor, 61:110-135. Schjelderup-Ebbe, T. 1935. Social behavior of birds. In A Handbook of Social Psy- chology, C. Murchison (Ed.), Clark Univ. Press, Worcester, Massachusetts, pp. 947- 972. Selander, R. K., and R. F. Johnston. 1967. Evolution in the House Sparrow. I. In- trapopulation variation in North America. Condor, 69:217-258. Shoemaker, H. H. 1939. Social hierarchy in flocks of the canary. Auk, 56:381-406. Simmons, K. E. L. 1954. Further notes on House Sparrow behaviour. Ibis, 96:478-481. Stokes, A. W. 1962. Agonistic behaviour among Blue Tits at a winter feeding station. Behaviour, 19:118-137. Summers-Smith, D. 1963. The House Sparrow. Collins, London. Thompson, W. L. 1960. Agonistic behavior in the House Finch. Part H: Factors in aggressiveness and sociality. Condor, 62:378-402. DEPARTMENT OF ZOOLOGY, UTAH STATE UNIVERSITY, LOGAN, UTAH 84321. (PRESENT ADDRESS: COLLEGE OF HUMAN BIOLOGY, THE UNIVERSITY OF WISCONSIN-GREEN BAY, MANITOWOC CAMPUS, MANITOWOC, WISCONSIN 54220). 29 JUNE 1968. AVIAN BILL-WIPING George A. Clark, Jr. This first review of the taxonomic distribution of bill-wiping was under- taken to determine whether occurrence of this trait might aid in clarify- ing evolutionary and systematic relationships among higher categories of birds. Sources of data are my field observations of bill-wiping in 27 passerine species and the cited publications. Although hundreds of papers were con- sulted, some records of bill-wiping have undoubtedly been missed. Bill-wiping typically involves rapid withdrawal of the side of the beak from base to tip closely adjacent to a foreign surface such as a branch or the ground. Excluded from consideration is wiping effected as the bill touches other parts of the body or that of another bird; such contacts are not usually described as bill-wiping. Wiping varies in detail even for an individual bird at different times. Many kinds of structures provide wiping surfaces; I have seen passerines wipe on rope clothesline, fence wire, the edge of a metal birdbath, and the rim of a metal incinerator. Birds may or may not be perched on an object upon which they wipe, e.g., they may sit on one branch yet wipe on another nearby. If both sides of the bill are wiped in a single session, the sides are usually alter- nated. The number of wipes per session also varies widely (Morris, 1957a) ; the maximum rate reported is 90 wipes in a few minutes by the estrildine Poephila bichenovi (Morris, 1957b). Details of wiping are often difficult to see in the field. It is reported that the bill may be open or closed during wip- ing (Dunham, 1966a). Moreover, the bill reportedly often does not contact the object adjacent to which it is “wiped” (Hinde, 1953; Morris, 1954). If the bill fails to touch, the term “wiping” is misleading in a literal sense but still descriptively convenient. Despite its many variations, bill-wiping appears on the whole to be a distinctive and readily recognizable behavioral character- istic. Hinde (1953 ) and Hardy (1963) have published illustrations of bill- wiping. FUNCTION As judged from its frequency and the component movements of head, neck, trunk, and legs, bill-wiping involves cumulative expenditure of substantial time and energy. It therefore seems likely that such bill-wiping is selectively advantageous, even though the benefits are frequently obscure. Cleaning. — As widely noted, birds frequently bill-wipe after eating messy foods such as suet, fruits, or juicy insects. Such wiping presumably aids sani- tation and may help to maintain bill mobility and streamlining. 279 280 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Those species not bill-wiping presumably use alternate ways of bill-cleaning, e.g., rubbing the bill on feathers or feet, pushing the bill into sand or other material, scratching with the foot, head shaking, and bathing. The cleaning methods appear to be effective, for free-living birds with conspicuously dirty bills are uncommon. Honing. — Hardy (1963) notes for the parrot Aratinga canicularis that wiping may have a honing function, as wiping is sometimes done, evidently deliberately, on rough barked trees. A scraping noise heard during bill-wiping by the Rose-breasted Grosbeak {Pheucticus ludovicianus; Dunham, 1966a) might indicate substantial contact of the bill in wiping. However, in examin- ing bills of study skins of various passerines with a binocular dissecting micro- scope, I find no clear evidence of the effects of wiping. If bill-wiping serves in honing, it would seem essential that the bill grow sufficiently rapidly to offset wear through honing. Hypothetically one would expect selection to yield growth patterns not requiring special wiping to main- tain or produce normal bill shapes. Unfortunately, not enough is known to correlate bill growth with bill-wiping, although there is much evidence that bills are continually growing and wearing away (Davis, 1954; Witschi and Woods, 1938; Wydoski, 1964). Wiping, serving primarily other functions, presumably produces some wear. As judged from data assembled by Pomeroy (1962) on bill abnormalities, the frequency of malformed bills is not correlated with the occurrence or ab- sence of bill-wiping. Displacement activities. — Birds often bill-wipe without apparent debris on the bill and not immediately after feeding, bathing, drinking, or manipulation of objects with the bill. Indeed, as noted above, in some cases the bill re- portedly does not contact the object against which it is “wiped” (cf. Morris, 1954) . Much wiping thus meets a standard criterion for displacement activi- ties in being seemingly irrelevant in a particular behavioral context. It is difficult to categorize adequately the variety of situations in which dis- placement bill-wiping occurs. In a common case, a bird feeding on the ground is flushed by another bird or person and after flying to a branch engages in hill-wiping. Wiping movements occur frequently during agonistic behavior (seeCoutlee, 1967; Dunham, 19665; Nero, 1963). Eurthermore, wiping may take place during predominantly sexual behavior as reported by Coombs (1960), Morris (1954), Moynihan (1963), and Summers-Smith (1963:24- 25). Nice (1943:40) and Reiskind (1965) give examples of bill-wiping fol- lowing contact with, or manipulation of, distasteful objects. Many of the fore- going examples involve situations in which birds are seemingly thwarted from completing an activity; however, some displacement wiping is associated with George A. Clark, Jr. AVIAN BILL-WIPING 281 transitions between activities without apparent thwarting. For example, I have observed a male Yellowthroat {Geothylpis trichas) fly to a branch, hill-wipe, and then begin to sing. Still other cases of wiping do not appear to involve thwarting, transition in activities, or cleaning. As examples, I have seen both the Yellow Warbler {Dendroica petechia) and the Prairie Warbler [D. dis- color) bill-wipe during pauses in periods of singing. As Brown (1964) points out, the factors eliciting displacement bill-wiping may be very subtle so that detecting them in the field is often difficult or impossible. That not all bill-wiping is a form of hill maintenance (i.e., cleaning or hon- ing) is suggested by wiping without contact and also by intraspecific varia- tions in frequency of wiping according to social rank or sex. Stokes (1963:13) observed more wiping in subordinate than in dominant partridges (Alectoris) . In contrast, Hinde (1953) found hill-wiping commoner in dominant than sub- ordinate Chaffinches {Fringilla coelebs) . Morris (1954) recorded a higher frequency of bill-wiping by males than females during precopulatory displays of Poephila guttata. The selective advantages in bill-wiping and other dis- placement activities are relatively unstudied but may involve changes in the physiological state of the bird and in its responsiveness to environmental stim- uli (cf. Rowell, 1961; Delius, 1966). It is curious that possible changes in internal state should be linked with such extensive body movements. SYSTEMATIC SURVEY Table 1 is a summary of species for which bill-wiping has been reported. For most species existing records of bill-wiping are fragmentary relative to the variety of contexts in which wiping may potentially occur. It is therefore premature to categorize species according to occurrence or frequency of bill- wiping in particular behavioral contexts. However, interspecific variations of this kind may occur widely. For example, Morris (19576) found that Loii- chura cucullata frequently preens as a displacement activity in contexts in which other estrildines show displacement bill-wiping. Probably all groups listed in Table 1 bill-wipe as a means of cleaning the bill, but bill-wiping as a displacement activity has thus far been reported ap- parently for only Phasianidae, Larus ridibundus, Psittacidae, and many pas- serines. The wide distribution of bill-wiping in parrots and passerines suggests that wiping may be characteristic for these two orders. I have found a few negative reports. Bill-wiping on a branch is unrecorded in waterfowl (Anatidae) despite arboreal perching by some species (McKinney, 1965:181). Variation in occurrence of wiping exists within the family Laridae. Tinbergen (1959:18, 52) notes that, when visited by a female, a male Black- headed Gull {Larus ridibundus) may peck at the ground and then bill-wipe. 282 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 1 Records of Bill-wiping Family Species Reference Tinamidae Nothoprocta cinerascens Lancaster, 1964: 280 Arcleidae Buteroides virescens Meyerriecks, 1960: 11 Tetraonidae Lagopus scoticus Watson and Jenkins, 1964: 146 Phasianidae Alectoris sp. Gallus gallus Colinus virginianus Goodwin, 1953; Stokes, 1963 Nice, 1962: 81 Nice, 1943: 40 Laridae Larus ridibundus Tinbergen, 1959 Psittacidae Aratinga canicularis Brotogeris jugularis Loriculus galagulus L. vernalis Melopsittacus undulatus Hardy, 1963 Power, 1967 Buckley, 1968 II 11 Brockway, 1964 Picidae Colaptes auratus Sphyrapicus varius Kilham, 1959 Kilham, 1962; Lawrence, 1967: 120 Forniicariidae Gymnopithys, 3 species Willis, 1967, 1968 Tyrannidae Empidonax traillii this study Hirundinidae Iridoprocne bicolor II II Corvidae Gyanocitta cristatn G. stelleri Aphelocoma caeridesceiis A. ultramarina Calocitta jormosa Corvus frugilegus Hardy, 1959; this study M U It It 11 It 11 II Coombs, 1960 Paradisaeidae Parotia carolae Paradisaea raggiana Frith, 1968 Rand and Gilliard, 1968 Paridae Parus atricapillus P. carolinensis P. major Reiskind, 1965 Brewer, 1961 Howard, 1951 Troglodytidae Troglodytes troglodytes Cam pylorhyn ch us brunneicapillus Armstrong, 1955: 30 Ricklefs, 1966 Mimidae Mimas polyglottos Dumetella carolinensis Toxostoma curvirostre this study II II Ricklefs, 1966 George A. Clark, Jr. AVIAN BILL-WIPING 283 Table 1 cont. Family Species Reference Turdidae Erithacus rabecula Luscinia megarhynchos Phoenicurus phoenicurus Sialia sialis Saxicola rubetra T Urdus migratorius Mustier, 1935 M It ft M this study Mustier, 1935 this study Sylviidae Hippolais icterina Sylvia atricapilla S. communis Mostler, 1935 n It II tt Muscicapidae Ficedula hypoleuca II It Bombycillidae Bombycilla cedrorum this study Laniidae Lanius excubitor L. ludovicianus Cade, 1962 Miller, 1931: 220-221 Sturnidae Sturnus vulgaris this study Vireonidae Vireo bellii V. olivaceus Nulan, 1960 this study Parulidae Dendroica petechia D. kirtlandii D. discolor Seiurus aurocapillus Seiurus sp. Geothylpis Irichas Setophaga ruticilla II II Mayfield, 1960: 66 this study It II II n tt II Ficken, 1962 Ploceidae Poepliila guttata P. bichenovi Loncliura cucullata L. punctulata L. striata Ploceus {= Sitagra) melanocephal us Passer domesticus Murris, 1954 Murris, 19576 It It Muynihan and Hall, 1954 Eisner, 1960 Cruuk, 1963 Summers-Smith, 1963 ; 24-25; this study Icteridae Xanthocephalus xanthocephalus Agelaius phoeniceus Icterus gal bill a Quiscalus quiscula Molothrus ater Neru, 1963 II II ; this study this study Ficken, 1963; this study Nice, 1943; Neru, 1963; tliis study 284 THE WILSON BULLETIN SejJteniber 1970 Vol. 82. No. 3 Table 1 cont. F amily Species Reference Thraupidae Habia rubica Willis, 1960 H. gatturalis tl II Fringillidae Richmondinae Pheucticus ludovicianus Dunham, 1966a, 19666; this study Eniberizinae Arremonops conirostris Moynihan, 1963 Junco hyemalis this study Spizella arborea It tl S. passerina tl tl Melospiza georgiana It tl M. melodia Nice, 1943: 21, 34; this study Carduelinae Fringilla coelebs Hinde, 1953; Rowell, 1961 F. monti fringilla Hinde, 1955-56 Serinus sp. Nice, 1943: 40; Hinde, 1955-56; Vince, 1961 Chloris chloris Hinde, 1955 Carduelis carduelis Hinde, 1955-56 Spinus tristis Coutlee, 1963, 1967 Acanthis flammea Dilger, 1960 Carpodacus purpureas this study Loxia curvirostra Tordoff, 1954 Pyrrhula pyrrhula Coccothraustes Hinde, 1955-56 coccothraustes It II Indeed, it regularly bill-wipes as a displacement activity, similar to the move- ments by which the bill is cleaned. This species thus differs from the Herring Gull {Larus argentatus) which tugs at vegetation rather than bill-wiping (Tin- bergen, 1959). This constitutes an example of intrageneric variation in the occurrence of bill-wiping. Van lersel and Bol (1958:7) in extensive observa- tions of the terns Sterna hirundo and 5. sandvichensis saw no bill-wiping. Lor the majority of families there are neither positive nor negative records. In watching such species as Killdeer {Charadrius vociferus) , Rock Doves [ Colurnba livia) , and Mourning Doves {Zenaidura macroura) , I have failed to see bill-wiping, but further data are needed. Present negative evidence sug- gests that bill-wiping is absent, or occurs rarely, in a variety of waterbirds. Another questionable group is the Trochilidae. DuBois (1938) reports an George A. Clark, Jr. AVIAN BILL-WIPING 285 Earliest Appearance Table 2 OF Bill-wiping in SOME Passerine Species Species Days Posthatching Reference Cyanocitta cristata 15 Hardy, 1959 Campylorhynchus brunneicapillus 24 Ricklefs, 1966 Toxostoma curvirostre 16 11 It Lanins ludovicianus 33 Miller, 1931: 220-221 Setophaga ruticilla 8 Ficken, 1962 Molothrus ater 14 Nice, 1943: 40 Ph eucti CHS 1 u dovician us 7-11 Dunham, 1966a Melospiza melodia 11 Nice, 1943: 21, 34 Seriniis conaria 11 or earlier Nice, 1943: 40 unsuccessful effort by a female Rufous Hummingbird {Selasphorus rufus) to wipe away a feather by rubbing her bill on the rim of the nest. After failing to dislodge the feather with her tongue, she eventually removed it by jabbing her bill downward into the nest. It is uncertain that the bill-wiping observed by DuBois corresponds to that of other birds. EVOLUTIONARY INTERPRETATIONS Although a few data are available on the ontogeny of bill-wiping (see Table 2 and the references cited therein), we know little about the possible roles of practice and learning in maturation of the trait. Nevertheless, in view of the absence of records of intraspecific variation in occurrence, the character ap- pears to be species-specific and hence presumably strongly influenced geneti- cally. Clearly much more must be learned about the occurrence of bill-wiping be- fore it can be broadly used taxonomically. Particularly needed are observa- tions on the presence or absence of the trait in additional nonpasserine groups. Bill-wiping is a seemingly simple feature and hence may have been acquired or lost more than once in evolutionary history. However, bill-wiping appears to be as potentially suitable a taxonomic character as some simple, but widely cited, morphological ones (e.g., feathering of the oil gland; Clark, 1964). As displacement activities are commonly believed to be a frequent evolu- tionary source for movements in stereotyped behavior, it would not be sur- prising if bill-wiping were found as a source in the evolution of certain dis- plays. There are a few possible examples. Orians and Christman (1968:76) suggest that one possible source of the bill-down postures in certain icterids and ploceids might be bill-wiping (see also Mitchell, 1966). Moreover, the 286 THE WILSON BULLETIN September 1970 Vol. 82. No. 3 sweeping movements of White-breasted Nuthatches (Sitia carolinensis) in pos- sible chemical defense of nests against squirrels may have been derived from bill-wiping (Kilham, 1968). SUMMARY Bill-wiping is reviewed for Tinamidae, Ardeidae, Tetraonidae, Phasianidae, Psittacidae, Picidae, and 20 families of Passeriformes. Bill-wiping occurs in at least one, but not all, species of Laridae and has not been reported for Anatidae. Functional interpretation of this behavior as a displacement activity remains uncertain. Bill-wiping appears to have moderate potential utility as a taxonomic character. ACKNOWLEDGMENT I thank Dr. James A. Slater for helpful criticism of an earlier version of the manuscript. LITERATURE CITED Armstrong, E. A. 1955. The wren. Collins, London. Brewer, R. 1961. Comparative notes on the life history of the Carolina Chickadee. Wil- son Bull., 73:348-373. Brockway, B. F. 1964. Ethological studies of the Budgeriger {Melopsittaciis undulatiis) : non-reproductive behavior. Behaviour, 22:193-222. Brown, J. L. 1964. The integration of agonistic behavior in the Steller’s Jay Cyanocitta stelleri (Gmelin). Univ. California Publ. Zook, 60:223-328. Buckley, F. G. 1968. Behaviour of the Blue-crowned Hanging Parrot Loriculus gcilguhis with comparative notes on the Vernal Hanging Parrot L. vernalis. Ibis, 110:145-164. Cade, T. J. 1962. Wing movements, hunting, and displays of the Northern Shrike. Wil- son Bulk, 74:386-408. Clark, G. A., Jr. 1964. Ontogeny and evolution in the megapodes (Aves: Galliformes) . Postilla, 78:1-37. Coombs, C. J. F. 1960. Observations on the rook Corvus frugilegiis in southwest Corn- wall. Ibis, 102:394-419. CouTLEE, E. L. 1963. Maintenance behavior of the American Goldfinch. Wilson Bulk, 75:342-357. CouTLEE, E. L. 1967. Agonistic behavior in the American Goldfinch. Wilson Bulk, 79: 89-109. Crook, J. H. 1963. The basis of flock organisation in birds. Pp. 125-149. In: W. H. Thorpe and 0. L. Zangwill (Ed.), Current problems in animal behaviour. Cambridge Univ. Press, Cambridge, England. Davis, J. 1954. Seasonal changes in bill length of certain passerine birds. Condor, 56: 142-149. Delius, J. D. 1966. Displacement activities and arousal. Nature, 214:1259-1260. Dilger, W. C. 1960. Agonistic and social behavior of captive Redpolls. Wilson Bulk. 72:115-132. DuBois, A. D. 1938. Observations at a Rufous Hummingbird’s nest. Auk, 55:629-641. Dunham, D. W. 1966fG Maintenance activities of the Rose-breasted Grosbeak. Wilson Bulk, 78:68-78. Dunham, D. W. 19666. Agonistic behavior in captive Rose-breasted Grosbeaks, Phcin liens liidovicianus (L.). Bebaviour, 27 : 160-173. George A. Clark, Jr. AVIAN BILL-WIPING 287 Eisner, E. 1960. The biology of the Bengalese Finch. Auk, 77:271-287. Ficken, M. S. 1962. Maintenance activities of the American Redstart. Wilson Bull., 74: 153-165. Ficken, R. W. 1963. Courtship and agonistic behavior of the Common Crackle, Qiiiscalus qidscula. Auk, 80:52-72. Frith, C. 1968. Some displays of Queen Carola’s Parotia. Avic. Mag., 74:8.5-90. Goodwin, D. 1953. Observations on voice and liehaviour of the Red-legged Partridge Alectoris rufa. Ibis, 95:581-614. Hardy, J. W. 1959. Studies in behavior and phylogeny of certain New World jays (Gar- rulinae). Univ. Kansas Sci. Bulk, 42:13-149. Hardy, J. W. 1963. Epigamic and reproductive behavior of the Orange-fronted Parakeet. Condor, 65:169-199. Hinde. R. a. 1953. The conflict between drives in the courtship and copulation of the Chaffinch. Behaviour, 5:1-31. Hinde, R. A. 1955. The courtship and copulation of the Greenfinch (Chloris chloris). Behaviour, 7:207-232. Hinde, R. A. 1955-56. A comparative study of the courtship of certain finches ( Fringil- lidae). Ibis, 97:706-745; 98:1-23. Howard, F. 1951. Abnormal bill of Great Tit. Brit. Birds, 44:350. Kiliiam, L. 1959. Early reproductive behavior of flickers. Wilson Bulk, 71:323-336. Kiliiam, L. 1962. Nest sanitation of Yellow-bellied Sapsucker. Wilson Bulk, 74:96-97. Kiliiam, L. 1968. Reproductive behavior of White-breasted Nuthatches. I. Distraction display, bill sweeping, and nest hole defense. Auk, 85:477-492. Lancaster, D. A. 1964. Biology of the brushland tinamou, Nothoprocta cinerascens. Bulk Amer. Mus. Nat. Hist., 127:269-314. Lawrence, L. de K. 1967. A comparative life-history study of four species of wood- peckers. Ornithok Monogrs., 5:1-156. Mayfield, H. 1960. The Kirtland’s Warbler. Cranbrook Institute of Science, Bloom- field Hills, Michi gan. McKinney, F. 1965. Tire comfort movements of Anatidae. Behaviour, 25: 120-220. Meyerriecks, a. j. 1960. Comparative breeding behavior of four species of North American herons. Pubk Nuttall Ornithok Club, 2. Miller, A. H. 1931. Systematic revision and natural history of the American shrikes (Lanius). Univ. California Pubk Zook, 38:11-242. Mitchell, I. G. 1966. Courtship patterns in some species of Coliuspasser. Ostrich, 37: 47-53. Morris, D. 1954. The reproductive behaviour of the Zebra Finch iPoephi/a guttata), with special reference to pseudofemale behaviour and displacement activities. Be- haviour, 6:271-322. Morris, D. 1957«. “Typical intensity” and its relation to the problem of ritualisation. Behaviour, 11:1-12. Morris, D. 19576. The reproductive behaviour of the Bronze Mannikin, Lonchura caciil- lata. Behaviour, 11:156-201. Mostler, G. 1935. Beobachtungen zur Frage der Wespenmimikry. Z. Morphok Okok Tiere, 29:381-454. Moynihan, M. 1963. Display patterns of tropical American “nine-primaried” songbirds. HI. The Green-backed Sparrow. Auk, 80:116-144. 288 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Moyniiian, M., and M. F. Hall. 1954. Hostile, sexual, and other social behaviour pat- terns of the Spice Finch {Lonchura punctulata) in captivity. Behaviour, 7:33-76. Nero, R. W. 1963. Comparative behavior of the Yellow-headed Blackbird, Red-winged Blackbird, and other icterids. Wilson Bull., 75:376-413. Nice, M. M. 1943. Studies in the life history of the Song Sparrow. H. The behavior of the Song Sparrow and other passerines. Trans. Linnaean Soc. New York, 6. Nice, M. M. 1962. Development of behavior in precocial birds. Trans. Linnaean Soc. New York, 8. Nolan, V., Jr. 1960. Breeding behavior of the Bell Vireo in southern Indiana. Condor, 62:225-244. Orians, G. H., and G. M. Christman. 1968. A comparative study of the behavior of Red- winged, Tricolored, and Yellow-headed Blackbirds. Univ. California Publ. Zook, 84. Pomeroy, D. E. 1962. Birds with abnormal bills. Brit. Birds, 55:49-72. Power, D. M. 1967. Epigamic and reproductive behavior of Orange-chinned Parakeets in captivity. Condor, 69:28-41. Rand, A. L., and E. T. Gilliard. 1968. Handbook of New Guinea birds. Natural His- tory Press, Garden City, New York. Reiskind, J. 1965. Behaviour of an avian predator in an experiment simulating Batesian mimicry. Anim. Behav., 13:466-469. Ricklefs, R. E. 1966. Behavior of young Cactus Wrens and Curve-billed Thrashers. Wilson Bull., 78:47-56. Rowell, C. H. F. 1961. Displacement grooming in the Chaffinch. Anim. Behav., 9: 38-63. Stokes, A. W. 1963. Agonistic and sexual behaviour in the Chukar Partridge {Alectoris graeca). Anim. Behav., 11:121-134. Summers-Smith, D. 1963. The House Sparrow. Collins, London. Tinbergen, N. 1959. Comparative studies of the behaviour of gulls (Laridae) : a progress report. Behaviour, 15:1-70. Tordoff, H. B. 1954. Social organization and behavior in a flock of captive, nonbreed- ing Red Crossbills. Condor, 56:346-358. Van Iersel, J. J. A., and A. C. A. Bol. 1958. Preening of two tern species, a study on displacement activities. Behaviour, 13:1-88. Vince, M. A. 1961. “String-pulling” in birds. HI. The successful response in Green- finches and Canaries. Behaviour, 17:103-129. Watson, A., and D. Jenkins. 1964. Notes on the behaviour of the Red Grouse. Brit. Birds, 57:137-170. Willis, E. 0. 1960. A study of the foraging behavior of two species of ant-tanagers. Auk, 77:150-170. Willis, E. 0. 1967. The behavior of hicolored antbirds. Univ. California Publ. Zook, 79:1-132. Willis, E. 0. 1968. Studies of the behavior of Lunulated and Salvin’s Antbirds. Condor, 70:128-148. WiTSCiii, E., and R. P. Woods. 1936. The bill of the sparrow as an indicator for the male sex hormone. Ik Structural basis. J. Exp. Zook, 73:445-459. Wydoski, R. S. 1964. Seasonal changes in the color of Starling hills. Auk, 81:542-550. BIOLOGICAL SCIENCES GROUP, UNIVERSITY OF CONNECTICUT, STORRS, CONNECTICUT 06268, 9 OCTOBER 1968. EGG TEETH AND HATCHING METHODS IN SOME ALCIDS Spencer G. Sealy Recent discussions on egg teeth (Wetherbee, 1959; Clark, 1961; Parkes and Clark, 1964) give little data on the Alcidae. While studying breed- ing biology of Parakeet [Cyclorrhynchus psittacula) , Crested {Aethia cris- tatella), and Least [A. pusilla) Auklets on St. Lawrence Island, Alaska, in 1966 and 1967, I had opportunity to observe egg teeth in several alcid species and hatching in the auklets and Horned Puffin {F ratercula corniculata) . These observations are supplemented by examinations of alcid chicks in the American Museum of Natural History (AMNH) examined by C. E. O’Brien, Los Angeles County Museum (LACM) examined by K. E. Stager, National Museum of Canada (NMC) examined by W. E. Godfrey, San Diego Natural History Museum (SDNHM) examined by J. E. Jehl, Jr., University of British Columbia Museum of Zoology (UBCMZ), University of Michigan Museum of Zoology (UMMZ), United States National Museum (USNM) examined by R. C. Banks, and University of Washington Burke Museum I UWBM ) examined by L. Spring. Specimens in UBCMZ and UMMZ were examined by myself. ANNOTATED LIST Alca torda. — Bedard Q969) reported the persistence of egg teeth in Razorbills up to the 14th day after hatching. Kartaschew (1960) and Perry (1940) figured egg teeth on the upper mandibles of this species. Chicks in SDNHM showed egg teeth on upper mandibles. Uria aalge. — Tuck (1961) mentioned the presence of egg teeth in Common Murres; Perry (op. cit.) figured it in this species. One chick in NMC showed an egg tooth on the upper mandible only but some chicks of this species in SDNHM showed both upper and lower egg teeth. Uria lomvia. — Tuck (op. cit.) mentioned the presence of egg teeth in Thick-billed Murres; Kartascbew (op. cit.) figured it in this species. Three chicks in NMC showed egg teeth on their upper mandibles only. Plautus alle. — Bateson (1961) figured the egg tooth on the upper mandible of a Dovekie. Cepphus grylle. — Winn (1950) observed egg teeth becoming relatively smaller follow- ing hatching and disappearing between the 25th and 35th day after hatching. Kartaschew (op. cit.) figured egg teeth on the upper mandibles of Black Guillemots. Eight chicks in NMC showed egg teeth on their upper mandibles; one of these chicks has what looks like a very small remnant of an egg tooth on its lower mandible also (Godfrey, pers. comm. ) . Cepphus columba. — Thoresen and Booth (1958) figured the egg tooth of newly hatched Pigeon Guillemots and Drent (1961) observed it in chicks up to 28 days of age. On St. Lawrence Island, 1 observed two chicks which lost it between the 27th and 30th days after hatching. Two newly hatched chicks in UBCMZ show small, hilateral protuberances on their lower mandibles; these were undetectable in chicks of about two weeks of age 289 290 THE WILSON BULLETIN September 1970 Vul. 82. No. 3 and older. Newly hatched Pigeon Guillemots in SDNHM also showed egg teeth on their lower mandibles. Brachyramphus marmoratum. — Tliree chicks in UBCMZ and three in UWBM showed egg teeth on their upper and lower mandibles; each chick had fledged and was in juvenal plumage. Drent and Guiguet (1961) mentioned egg teeth being present on the upper mandibles of the UBCMZ specimens but did not mention egg teeth on their lower mandibles. Brachyramphus hrevirostre. — Thompson et al. (1966) figured and described the egg tooth on the upper mandible only in one chick. R. M. Mengel (pers. comm.) examined this specimen and reported an egg toothdike structure also on its lower mandible; it takes the form of a double swelling with a slight trough separating the protuberances. Endomychura hypoleuca. — Three chicks in AMNH and one in LACM show vestiges of egg teeth on their upper mandibles only. Chicks of this species in SDNHM show egg teeth on both mandibles and one chick in USNM which is labeled “just hatched” (Banks, pers. comm.) does not have an egg tooth on either mandible which indicates that it possibly fell off soon after hatching or during preservation. Endomychura craveri. — Chicks in SDNHM showed egg teeth on their upper mandibles only; further observations are needed to establish the presence of egg teeth on their lower mandibles. Synthliboramphus antiquum. — Drent and Guiguet (op. cit.) figured the egg tooth of this species. Newly hatched chicks in UBCMZ showed egg teeth on their upper and lower mandibles. Egg teeth on the upper mandibles in 11 chicks examined by me averaged 2.5 mm in diameter at their base. Synthliboramphus wumizusume. — ^Three newly hatched chicks in UMMZ showed no egg teeth; however, each chick’s label contains the notation “egg tooth white” (pre- sumably referring to that on the upper mandible only). As in E. craveri, additional in- formation is needed to establish the presence of egg teeth on their lower mandibles. Ptychoramphus aleutica. — Tlioresen (1964) figured the egg tooth on the upper mandible of a one-day-old chick; an 11-day-old chick showed no egg tooth. Egg teeth of nine newly hatched chicks in UBCMZ averaged 1.0 mm in basal diameter. Chicks in LACM, UBCMZ and SDNHM showed no egg teeth on their lower mandibles. Cyclorrhynchus psittacula. — Tlie egg tooth, found only on the upper mandible, averages 1.5 mm in diameter at the base at hatching and gradually becomes smaller until it disappears between the 8th and 10th days after hatching. Aethia cristatella. — Egg teeth of the upper mandibles average 2.4 mm in basal diam- eter and, like those of C. psittacula, become smaller and gradually disappear between the 8th and 10th days after hatching. Aethia pusilla. — Egg teeth, on upper mandibles only, average 1.0 mm in basal diameter at hatching and persist up to about the 12th day after hatching. Aethia. pygmaea. — Two downy chicks in USNM showed egg teeth on their upper mandibles only. Cerorhinca. monocerata. — Four chicks in UWBM, two of them about one or two weeks old, do not have egg teeth. Richardson (1961) figured a four-week-old chick that did not have an egg tooth; three chicks about this age in UBCMZ also showed no egg teeth. Three chicks from pipped eggs in UWBM showed egg teeth on their upper mandibles only (L. Spring, pers. comm.) which indicates that egg teeth in this species are appar- ently lost within a week or two after hatching. Fratercula arctica. — Kartaschew (op. cit.), Lockley (1953), and Myrherget (1959) figured the egg tooth on the upper mandible. Spencer G. Sealy ALGID EGG TEETH AND HATCHING 291 Frcitercida corniciilata. — I observed ihe persistence of an egg tooth on the upper mandible of a nestling on St. Lawrence Island up to the 29th day after hatching. The basal diameter of three egg teeth at hatching averaged 3.5 mm. Lunda cirrhata. — Drent and Guiguet (op. cit.) figured the egg tooth of the upper mandible. Chicks in SDNHM showed egg teeth on their upper mandibles. Each alcicl species examined possessed an egg tooth on the culmen near the tip of the upper mandible ; the absenee of egg teeth on some chicks is prob- ably attributable to loss during handling and preservation. This egg tooth does not encompass the entire tip of the mandible as is the ease in seolopacids (Jehl, 1968). In Cerorhinca monocerata the egg tooth appears to be de- eiduous like that of seolopacids and apparently is lost soon after hatehing. Chieks of Brachyramphus marmoratum, on the other hand, retain it until their Juvenal plumage is assumed and they have fledged (see Drent and Guiguet, 1961:80). Egg teeth in auklets and probably most other aleids gradually disappear without, apparently dropping off abruptly. Egg teeth or teeth-like structures were found on the lower mandibles of Uria aalge, Cepphus grylle, C. columha, Synthliboramphus antiquum, Endo- mychura hypoleuca, B. marmoratum, and B. brevirostre. These egg teeth of lower mandibles of Synthliboramphus and B. marmoratum eonsist of thin, apparently ealcareous, sheets that eover the entire tips of the mandibles. The egg teeth on the lower mandibles of C. columba and B. brevirostre differ in that they are in the form of a double, apparently bilateral, protuberanee. The time of disappearance of this strueture also varies; within a few days in C. columba and retained at least until the young have fledged in B. marmoratum. Jehl (1968) diseussed the apparent signifieance of the egg tooth, if it should be ealled such, of the lower mandible in seolopacids. He found no obvious role in hatehing and stated that it may function to protect the delicate tip of the lower mandible during hatching. It is interesting to note that those aleids so far shown to possess an “egg tooth” on their lower mandibles have pointed bills with upper and lower mandibles being of nearly equal length. I have no observations on hatching in those species with egg teeth on their lower mandibles but in auklets, where egg teeth are present only on upper mandibles, the lower mandibles are not involved in hatching. It is possible that the funetion of the “egg tooth” on the lower mandibles of aleids with “pointed beaks” may be also of a protective nature. The time between the oecurrence of the first cracks on the shell and the emergence of the ehick from the shell is variable in the auklets and Horned Puffin. This interval in four eggs of C. psittacula was two to four days (mean, 3.0 days), in eight eggs of A. cristatella was two to six days (mean, 3.3 days), in 27 eggs of A. pusilla was two to seven days (mean, 3.2 days), and in two eggs of F. corniculata was four to five days (mean, 4.5 days) . In 292 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 hatching of anklets the first cracks appear at a level approximately one-third the distance from the larger to the smaller end of the egg. Pip holes then progressively develop until they reach about 0.7 cm in diameter about two days later in C. psittaculu and A. cristatella and 0.5 cm in A. pusilla about three days after the initial cracking. With the egg tooth in contact with the shell the chick gradually cuts off the large end, pushes the resulting loose cap upwards, and emerges. The loose end is usually pulled back into “place” by a portion of adhering outer shell membrane. This sequence is similar in F. corniculata except that the pip hole, ultimately 0.9 cm in diameter, forms two to three days after the first cracks appear and the large end is cut off at an angle to the long axis of the egg rather than perpendicular to it as in the auklets. These hatching methods are similar to that of Cepphus coliimba ( Drent, 1961) but the time involved in hatching by auklets is more variable than in Alca torda I Bedard, 1969), C. columba (Drent, op. cit.), and Ptychoramphus aleutica (Thoresen, 1964). In F. arctica, Myrberget (1962) found the average time from the appearance of the first cracks to emergence of the chick to be 4.3 days. In 37 out of 50 cases he found the “lid” of the egg inside the large section of the shell. Tuck (1961:155) stated that two or more days may be required for murre chicks {Uria spp.) to hatch, and occasionally “the adult assists by pecking away all or part of the hard, calcareous shell.” Adult auklets were not observed in the present study helping chicks out of the eggs. ACKNOWLEDGMENTS I should like to thank George A. Clark, Jr. for kindly examining two Cepphus chicks, providing helpful suggestions, and reading the manuscript. Joseph R. Jehl, Jr. made available a copy of his paper then in press and provided additional suggestions and information. Robert M. Mengel provided an illustration and description of egg teeth of a Kittlitz's Murrelet chick and Jean Bedard kindly read the manuscript. I am grateful to the curators of the museums listed in the introduction for examining alcid chicks for the presence of egg teeth. The study on St. Lawrence Island was made possible by a National Research Council of Canada grant to M. D. F. Udvardy; additional financial aid was provided by a Louis Agassiz Fuertes Research grant from the Wilson Orni- thological Society. LITERATURE CITED Bateson, P. P. 1961. Studies of less familiar birds. 112. Little Auk. Brit. Birds, .54:272-277. Bedard, J. 1%9. Histoire Naturelle du Code, Alca torda, L., dans le golfe Saint-Laurent, Province de Quebec, Canada. Etude du Service Canadien de la Fauna. No. 7. Clark. C. A., Jr. 1%L Occurrence and timing of egg teeth in birds. Wilson Bull., 73:268-278. Drent, R. H. 1961. Breeding biology of the Pigeon Guillemot (Aves: Cepphus). M.A. Thesis, University of British Columbia. Sjiencer C. Sealy ALGID EGG TEETH AND HATCHING 293 Drent, R. H. and C. J. Guiguet. 1961. A catalogue of Biitisli Columl)ia sea-hird colonies. Occ. Papers British Columbia Prov. Mus. No. 12. Jeiil, J. R., Jr. 1%8. Tlie egg tooth of some charadriiform birds. Wilson Bull., 80: 328-330. Kartasciiew, N. N. 1%0. Die Alkenvogel des Nordatlantiks. Neue Brehm Biicheri Nr. 257, Wittenberg. Lockley, R. M. 1953. Puffins. Dent, London. Myrberget, S. 1959. Lundeura pa Lovunden, og lundebastanden der. Fauna, 12:143-156. Myrberget, S. 1962. Underspkelser over forplantningsbiologien til Lunde ( Fratercula arctica (L.) ). Medd. fra Statens Viltunderspk, 11:1-51. Parkes, K. C. and G. a. Clark, Jr. 1964. Additional records of avian egg teeth. Wilson Bull., 76:147-154. Perry, R. 1940. Lundy, Isle of Puffins. London. Richardson, F. 1%1. Breeding biology of the Rhinoceros Auklet on Protection Island, Washington. Condor, 63:456-473. Thompson, M. C., J. Q. Hines, and F. S. L. Williamson. 1966. Discovery of the downy young of Kittlitz’s Murrelet. Auk, 83:349-351. Thoresen, a. C. 1964. The breeding behavior of the Cassin Auklet. Condor, 66: 456^76. Thoresen, A. C. and E. S. Booth. 1958. Breeding activities of the Pigeon Guillemot Cepphus columba columba (Pallas). Walla Walla Coll., Publ. Dept. Biol. Sci., No. 23. Tuck, L. M. 1961. The murres. Canadian Wildlife Seiwice Series, No. 1. Wetherbee, D. K. 1959. Egg teeth and hatched shells of various bird species. Bird- Banding, 30:119-121. Winn, H. E. 1950. Tlie Black Guillemots of Kent Island, Bay of Fundy. Auk, 67: 477-485. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER 8, BRITISH COLUMBIA. (PRESENT ADDRESS: MUSEUM AND DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MICHIGAN, ANN ARBOR, MICHIGAN 48104), 14 AUGUST 1968. GROWTH RATES AND SEX RATIOS OE RED-WINGED BLACKBIRD NESTLINGS Larry C. Holcomb and Gilbert Twiest The mean growth in weight and tarsus length for male and female Red- winged Blackbird [Agelaius phoeniceus) nestlings has been reported by Williams (1940). Holcomb and Twiest will report elsewhere on Redwing nestling mean growth and growth “rate.” It was found that there was no dif- ference in growth of Redwing nestlings raised either in a marsh or an upland habitat. There was some brood reduction, however, in the upland habitat. It is important to establish that Redwing nestlings grew at the same rate in up- land and marshes because this paper reports growth of birds from both en- vironments analyzed together. Allen (1914), Beer and Tibbitts (1950), Meanley and Webb (1963), Nero (1956), and Orians (1961) have documented beyond any doubt that the Redwing is polygamous. A male usually has between one and three females in his territory; two is most common. This suggests an adult female-male ratio of 2:1. First-year males, however, do not usually breed, and since there is not adequate knowledge about the fraction of first-year females breeding, one cannot say that there are two adult females for every male. In this paper the objectives are to 1) discover whether there is a difference in growth rate (as presented by Brody, 1945; Dawson and Evans, 1957, 1960; Banks, 1959; and Maher, 1964) in weight of male and female nestling Red- wings, 2 ) show the mean growth and rate of growth in weight and body parts of male and female nestlings, 3) show the time of feather capsule projection and fringing and growth of feathers in eight major feather tracts of male and female nestlings, 4) show the growth of body parts, each of which contributes to ontogeny of behavior, and 5) evaluate methods of sexing nestling Redwings by weight, and to show some reasons why a difference may exist in the adult ratio of males and females. METHODS AND PROCEDURES The study was done at a marsh at Battle Creek, Michigan, in 1965 and in an upland region in Toledo, Ohio, in 1964 and 1965. The nests were visited at least once each day. With few exceptions, a nest was visited at 24 ± 1 hour intervals. Nestlings were marked in the sequence of hatching hy placing fingernail polish on their claws (claw 1, 2, etc.). New polish was added as it hecame worn. The weight was obtained to the nearest one-tenth gram on a douhle-beam balance after the nestling had been handled sufficiently to cause voiding of wastes. 294 Holcomb and Twiest REDWING GROWTH RATES 295 Measurements of growth were made on the following parts of nestlings: toe span — distance from the tip of toe one to the tip of toe three when extended; nearest mm. This characteristic is important in the development of the righting reflex and allowing the nestling to grasp and balance (Holcomb, 1966). total body length — ^distance from the anterior tip of the culmen to the tip of the tail (including rectrices when present) — nearest mm tarsus — nearest one-half mm wing — radiale region to the tip of the phalanges (before feathers were present) and to the tip of primary eight after it emerged (wing chord) — nearest mm Three head portions were measured so that observers studying behavior of gaping as a parental stimulus could refer to more than one standard, mandibular tomium — distance from the anterior tip of the lower mandible to the commissural point — nearest mm mandible tip (culmen) to nostril opening — distance from the anterior tip of the culmen to the anterior edge of the nostril opening — nearest one-half mm gape width — distance across the base of head from one commissural point to the other — nearest mm Each of the eight feather tract regions were examined each day and if one feather capsule had pushed through the epidermis it was recorded as projecting. After the feather capsules had projected, they were examined each day, to determine when the capsule was broken and feather barbs were visible. This was called “fringing” of the feather capsule. One feather was measured from each of eight tracts each day after projection occurred. In most tracts one could not be sure that the same feather was measured each day, but the feathers were so near the same length in an area that the choice of different feathers should affect the mean values very little. The following feathers were measured to the nearest mm: caudal tract — left outermost rectrix alar tract — first (most proximal) primary (left wing) humeral tract — the longest feather — (usually found in the middle of the tract running parallel with the body) capital tract — center of the coronal region spinal tract — longest feather in the interscapular region ventral tract — longest feather in the axillar region crural tract — longest feather in the mid-portion of the anterior side of the leg femoral tract — longest feather in the mid-portion. Wetherbee (1957) describes the regions from which feathers were measured in this study and Holcomb and Twiest will pul)lish a report containing a figure showing the exact locations. The mean and standard errors were calculated for all of the measurements. The b values (regression coefficients) for the slopes of the growth curves for weight were calculated and a two-sided Students’ f-test was used for determining significance (p < 0.05). Growth in Redwings over the entire nestling period was nonlogarithmic. Thus, in determining growth rate, the formula presented l)y Banks (op. cit.) was used. 296 THE WILSON BULLETIN September 1970 Vo). 82, No. 3 6! 4 2. I . ff. 6. 4. E E 4 VENTRAL CAUDAL / /CAPITAL SPINAL □ MALE 10 M.WING LENGTH. I »■»»■«»>» » 0 5 10 Fig. 1. Mean values are plotted in a semilogarithmic fashion for increase in weight (grams) and length (mm) of other body components and eight feather tracts of male and female Redwing nestlings. The smallest value is 0.5 mm; the greatest is 116.7 mm. RESULTS AND DISCUSSION Mean growth and growth rates. — Ligure 1 shows the growth in weight of males and females on a semilogarithmic scale. There is a distinct separation of the growth curves for male and female nestlings and the slopes were signifi- cantly different. Ligure 1 shows the increase in weight and growth in length of different ana- tomical regions through day 10, and Table 1 shows the instantaneous relative growth rate ( R ) . The mean growth increments are greater each day for male nestlings hut not significantly different except for weight. A simple index was calculated to show mean values of the rates of growth over the entire nestling period, i.e., the R (rate) values were summed for each characteristic and then divided by the number of days. The mean rate of Holcomb and Twiest REDWING GROWTH RATES 297 Table 1 Redwing Male AND Female Nestling Instantaneous Relative Growth Rates (R) FOR Weight and Other Characteristics N R N R R R R R R R Day Sex Wt. Weight Other char. Lower mandible Mandible tip to nostril Gape width Toe span Wing length Total lengtli Tarsus length 0 M 47 34 F 58 36 1 M 42 45 29 19 16 18 20 18 11 21 F 61 43 37 18 16 18 22 20 13 22 2 M 43 46 30 18 15 19 26 27 15 25 F 60 42 38 15 13 15 24 28 12 22 3 M 44 33 31 10 14 8 20 28 11 23 F 61 34 36 12 16 9 22 31 13 25 4 M 42 34 29 10 12 6 23 37 13 22 F 53 27 33 8 9 4 18 30 12 19 5 M 42 25 32 6 12 2 14 28 11 16 F 58 24 36 7 13 1 13 28 9 16 6 M 46 18 34 5 9 2 8 21 7 12 F 60 14 36 2 8 0.4 6 18 6 12 7 M 45 11 32 3 10 -2 5 13 7 10 F 63 7 39 3 10 -1 4 13 6 5 8 M 41 7 28 4 8 -0.3 5 11 4 5 F 56 4 38 2 7 -1 1 9 6 4 9 M 34 8 23 1 7 -2 2 8 6 2 F 40 5 29 2 6 -1 3 7 6 2 10 M 22 2 18 3 3 -5 3 8 4 4 F 20 1 17 1 4 -5 2 5 4 0.3 Index M 23 8 11 5 13 20 9 14 F 20 7 10 4 12 19 9 13 growth throughout the entire nestling period could then be compared for each component. Rates of growth were somewhat faster for males than females in most cases but there were no significant differences. Gape width was the only characteristic declining in size after day six. This was due to a decrease in the fleshy rictal portions. The index for growth over the 10-day nestling pe- riod indicates the relative growth of different portions of the body. 298 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Projection Table 2 AND Fringing of Feather Tracts in Male and Female Redwing Nestlings Given in Percentage of Individuals where It Has Occurred Caudal Capital Spinal Crural Femoral Day Sex N P F P F P F P F P F 3 M 40 3 25 3 13 F 52 6 44 8 38 4 M 38 11 8 95 76 95 F 48 42 27 98 85 100 5 M 39 79 59 100 100 100 F 53 85 79 100 100 6 M 38 100 3 100 21 18 29 F 53 100 6 100 49 42 51 7 U 36 44 8 94 92 97 F 53 49 32 98 92 94 8 M 32 100 100 100 100 100 F 46 100 91 100 100 100 9 F 46 100 Alar Humeral Ventral Day Sex N P F P F P F 1 M 39 5 F 54 12 2 M 40 93 3 F 55 95 9 3 M 40 100 50 28 F 52 100 62 48 4 M 38 100 95 F 48 100 100 .5 M 39 8 100 F 53 19 8 15 6 M 38 87 68 71 F 53 94 74 87 7 M 36 100 100 100 F 53 100 100 100 Projection, fringing, and growth of feathers. — Table 2 shows the percentage of each sex that had feathers projecting from the epidermis and the capsules fringing on the ends. The females had feathers projecting and fringing some- what earlier than males. Holcomb and 1‘wiest REDWING GROWTH RATES 299 Table 3 Redwing Male and Female Feather Tract Growth Rate (R) Instantaneous Percentage Day Sex N Caudal Alar Humeral Capital Ventral Spinal Crural Femoral 3 iM 28 115 F 32 126 4 M 26 100 124 F 33 87 106 119 127 146 5 M 30 57 82 99 103 76 84 F 36 97 52 77 84 82 78 83 6 M 27 78 41 51 95 61 64 60 64 F 34 82 37 45 84 55 61 54 54 7 M 24 69 24 32 59 38 41 25 44 F 33 69 24 31 56 40 33 35 37 8 M 20 46 21 25 47 29 30 33 29 F 28 40 16 17 29 22 25 11 17 9 M 16 39 15 22 27 25 20 16 25 F 23 35 15 20 24 22 18 21 20 10 M 12 26 11 16 20 22 23 24 18 F 13 21 7 9 11 14 13 7 15 Index M 52 67 63 50 50 52 42 49 ( for first F 64 65 55 41 64 66 40 67 five days) Figure 1 shows the mean growth of feathers and Table 3 shows the rate of growth in the different feather tracts. Males and females had feathers of about the same length at fledging. An index was obtained by calculating the mean of the growth rate for only the first five days of growth for each feather tract because the caudal and capital tracts did not appear as early as the other feather tracts and comparative values were desired. The feathers grew at a faster rate than other characteristics measured. This is necessary if they are to provide their function by the time fledging occurs. Sexing nestlings by weight. — The sex was determined by weight after nest- lings reached an age of eight to ten days. Males had an overall different ap- pearance. Their feather cover developed slower than females and they were more clumsy in their movements. Each individual was marked so that weight increases could be traced backward in time. The values for weights of nest- lings are shown in Figure 2. There is overlap in weights of males and females yet on day 10. On day seven, 24 of 64 females weighed 27 or more grams and 300 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 WEIGHT (GRAMS) WEIGHT (GRAMS) 48 (/) 2.5 30 35 40 WEIGHT (GRAMS) Fig. 2. Weights of Redwing male and female nestlings on A) day 8; 95 birds, Bj day 9; 75 birds, C) day 10; 41 birds. two of 45 males weighed less than 27 grams. Nero (1961) reported that Red- wing nestlings could be sexed on the basis of weights beginning on day seven : 7th day — female below 27 g, male above; 8th day — female below 30 g. male above; 9th and 10th days — female below 33 g, male above 36. Williams (1940) reported too much overlap yet on day seven. His method on day eight was the same as Nero’s. Williams’ data for day nine indicate all females are 33 grams or below and all males 37 grams or above, and for day 10, females 33 or below and males 38 or above. If we used either of the methods proposed by Nero or Williams to sex our nestlings, we would have made several errors. We concede that it would he impossible to show a method that would work Holcomb and Twiest REDWING GROWTH RATES 301 without failure in sexing Redwing nestlings. We would prefer not to recom- mend criteria for determining sex before day eight. Even then, there will he some error when using only weight. We would prefer to make these recom- mendations for sexing nestlings of known age: Day 8 — female under 31 grams, male 31 grams or over; Day 9 — female under 33 grams, male 33 grams or over; Day 10 — female under 33 grams, male 35 grams or over. Ratio of males to females fledged. — The egg sequence producing males and females was: egg one — 16 males, 24 females; egg two — 20 males, 19 females; egg three — 11 males, 15 females; egg four — 4 males, 10 females. The sex was determined for 50 males and 68 females. Of this group, 41 males (82 per cent) and 54 females (79 per cent) were successfully fledged. The mean duration of nestling life is shorter for females than males (9.2 vs. 9.7 days ) . The reasons for earlier fledging in females may well be that they obtain the adult size faster. The feathers project and fringe a little earlier in females and by day nine they are as long or longer than males in every tract. There is also faster feather development compared to total body weight. For instance, the first primary (alar tract) has the same mean length for males and females on day nine. On day nine, males weigh a mean of 9.2 more grams than females, and the length of the wing is only 3.2 mm longer. This would suggest that the females leave earlier, because they have lighter wing loading than males. We believe that there may be no difference in the ratio of males to females in the first summer, and if there is any difference, it may favor females. Males stay in the nest somewhat longer than females. As young are more subject to predation than eggs (Young, 1963), more females may be fledged. The cap- ture of more males than females in mist nets (Meanley, 1964) and live traps ( Giltz, pers. comm., and trapping by Holcomb) may result from males being attracted to other birds in a trap, due to aggressive or gregarious tendencies. Perhaps males respond faster to calls of individuals already captured. The more aggressive nature of males may also make them less timid than females in approaching a capturing device. This same lack of timidity may also make them more vulnerable to predation than the females, and thus contribute to an excess of females for a polygamous mating system (see Selander, 1965). SUMMARY The b values for the slope of the growtli curves for weight of Red-wiiiged Blackbird male and female nestlings showed a significant difference (p<0.05); the males grew faster. An index for rates of growth for weight, lower mandible, mandible tip to nostril, gape width, toe span, wing length, total length, and tarsus length showed that males grow faster only in weight. Growth rates are presented for eight major feather tracts of males and females; there were no sexual differences. 302 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Feather capsules project from the epidermis and fringe on the ends in a greater per- centage of females earlier than males. Therefore, although feathers grow at a little faster rate in males, females have feathers nearly the same length in each tract near fledging time. Red-winged Blackbird nestlings can usually be sexed on the basis of weight by day eight. However, there was some overlap in weights of male and female nestlings on day 10. A revision of a method for sexing nestlings on the basis of weight is given. A ratio of males to females hatched from eggs of known laying sequence is given. The sex was determined on 50 males and 68 females of which 41 males and 54 females fledged. A secondary ratio of 50 : 50 is suggested and hypotheses for reasons leading to an adult ratio in favor of females are given. ACKNOWLEDGMENTS We would like to express appreciation for the aid given by The University of Toledo; Midland College, Fremont, Nebraska; The Ohio Agricultural Research and Development Center; Battle Creek Community College, Battle Creek, Michigan. We also extend thanks to C. Richard Weaver for planning of statistical evaluations and computer programming, and to George F. Shambaugh, Howard Y. Forsythe, Maurice L. Giltz and Loren S. Putnam who read an earlier copy of the manuscript. Helpful comments were made on a later version by Richard V. Andrews and Robert W. Belknap. LITERATURE CITED Allen, A. A. 1914. The Red-winged Blackbird; a study in the ecology of a cattail marsh. Proc. Linnaean Soc., New York, 24-25:43-128. Banks, R. C. 1959. Development of nestling White-crowned Sparrows in central coastal California. Condor, 61:96-109. Beer, J. R., and D. Tibbitts. 1950. Nesting behavior of the Red-wing Blackbird. Flicker, 22:61-77. Brody, S. 1945. Bioenergetics and growth. Reinhold, New York. Dawson, W. R., and F. C. Evans. 1957. Relation of growth and development to temperature regulation in nestling Field and Chipping Sparrows. Physiol. Zook, 30:315-327. Dawson, W. R., and F. C. Evans. 1960. Relation of growth and development to tem- perature regulation in nestling Vesper Sparrows. Condor, 62:329-340. Holcomb, L. C. 1966. Red-winged Blackbird nestling development. Wilson Bulk, 78: 283-288. Maher, W. J. 1964. Growth rate and development of endothermy in the Snow Bunting ( Plectrophenax nivalis) and Lapland Longspur {Calcarius lapponicus) at Barrow, Alaska. Ecology, 45:520-528. Meanley, B. 1964. Origin, structure, molt, and dispersal of a late summer Red-winged Blackbird population. Bird-Banding, 35:32-38. Meanley, B. M., and J. S. Webb. 1963. Nesting ecology and reproductive rate of the Red-winged Blackbird in tidal marshes of the upper Chesapeake Bay region. Chesa- peake Sci., 4:90-100. Nero, R. W. 1956. A behavior study of the Red-winged Blackbird. 1. Mating and nesting activities. Wilson Bulk, 68:5-37. Nero, R. W. 1961. Red-winged Blackbird. In Bird Banding Manual. U. S. Dept, of Interior, Laurel, Maryland. Holcomb and Twiest REDWING GROWTH RATES 303 Orians, G. H. 1961. The ecology of blackbird {Ageluius) social systems. Ecol. Monogr., 31:285-312. Selander, R. K. 1965. On mating systems and sexual selection. Anier. Naturalist, 99: 129-141. Wetiierbee, D. K. 1957. Natal plumages and downy pteryloses of passerine birds of North America. Bull. Amer. Mus. Nat. Hist., 113:343-436. Williams, J. F. 1940. The sex ratio in nestling eastern Red-wings. Wilson Bull., 52:267-277. \ OUNG, H. 1963. Age-specific mortality in the eggs and nestlings of blackbirds. Auk, 80:145-155. DEPARTMENT OF BIOLOGY, CREIGHTON UNIVERSITY, OMAHA, NEBRASKA 68131 AND DEPARTMENT OF BIOLOGY, CLARION STATE COLLEGE, CLARION, PA. 16214. 14 FEBRUARY 1968. REQUESTS FOR INFORMATION Desire data on body and/or feather weights in California quail and ring-necked pheasant for Ph.D. research topic. Especially desire data from limited circulation or un- published sources. Can also utilize similar data on other phasianid species. If possible, please list individually with date, location, sex of bird, age of bird if determinable and name of collector. Send to Carl Phillips, Dept, of Zoology, U.B.C., Vancouver 8, B.C., Canada. During the autumn migration of 1970 the Ontario Bird Band Association hopes to band and color-mark several hundred Semipalmated Sandpipers and Sanderling at Long Point, Ontario. Information on the movement of these sandpipers is essential to research presently underway on the energy requirements of their migration. We would greatly appreciate it if anyone sighting these birds would report their observations to Dr. A. Salvadori, Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario. The following information would be appreciated; Species: Location: (including nearest city or town) Dates: Color: (birds will be colored on the breast or abdomen with a single color, either pink, orange, blue, green, yellow or purple). Leg that has lieen banded: (This will tell if the bird is an adult or an immature.) Any information on what other birds are with the marked individuals would be very useful. COWBIRD PARASITISM AND NESTING SUCCESS OE LARK SPARROWS IN SOUTHERN OKLAHOMA George A. Newman Friedmann (1963) considers the Lark Sparrow {Chondestes grammacus) to be a relatively uncommon host of the Brown-headed Cowbird (Molo- thrus ater) . During the summer of 1968, I made observations of 33 active Lark Sparrow nests in the vicinity of the University of Oklahoma Biological Station on the north side of Lake Texoma approximately 2 miles east of Willis, Marshall County, Oklahoma. These observations were made from 7 June 1968, through 1 August 1968. The purpose of the study was to seek information on the incidence of Cowbird parasitism upon Lark Sparrows and to gain addi- tional nesting data on Lark Sparrows. Dr. George M. Sutton and I banded a total of 35 Lark Sparrow nestlings during the time of the study. NESTING SITES Of the 33 nests observed, 10 were located on the ground in pasture land which was grazed periodically throughout the summer. Another ground nest was located in a cultivated peanut field. These nests were usually placed at the bases of small herbaceous or woody plants which provided some shade during the day. Three of the ground nests, however, were built in short grasses and were relatively unprotected. The following eight species of plants were utilized as ground nesting sites: Asclepias viridis, Cnidoscolus texanus, Trifolium repens, Diospyros virginiana, Cjnodon daetylon, Andropogon scoparius, Smi- lax Bona-nox, and Arachis hypogaea. Twelve species of plants were used as nesting sites by Lark Sparrows that built their nests above ground ( Fig. 1) : Cupressus arizonica, Pinus sp., Jiinip- erus virginiana, Rosa setigera. Lager stroemia indica. Thuja oceidentalis, Ulma alata, Salix nigra, Quercus stellata. Yucca sp., Crataegus sp., Madura pomi- fera. Three nests were unusual and warrant mentioning. Nest 23 was situated in a cavity of a dead willow (Salix nigra). The nest was loosely constructed and consisted of a matting of medium sized grasses upon which a lining of small grasses and rootlets was placed. When found this nest had six eggs, four Lark Sparrow eggs and two Cowbird eggs (Fig. 2). The nest was destroyed by a predator before the eggs hatched. Nest 6 was built under a “cow chip” which had been raised by grass. The “chip” completely surrounded the nest except for an opening to the southeast. Four Lark Sparrow eggs were laid in the nest; all of them hatched. A heavy rain washed away the nest before the young fledged. The foundation of nest 25 was built by a Mockingbird and the lining 304 George A. Newman LARK SPARROW NESTING SUCCESS 305 Fig. 1. Lark Sparrow on nest in Juniperus virginiana. placed by a Lark Sparrow. I did not observe any encounters between tbe two species. It appeared that the Mockingbird had abandoned the nest before its completion and only after it was abandoned did the Lark Sparrow utilize it. Two Lark Sparrow eggs were laid in the nest; both eggs hatched and the young fledged. PREDATION Nesting success was significantly greater for nests built above ground (44.5 per cent) than for nests built on the ground (23.7 per cent) . These per- centages are based upon the number of Lark Sparrows fledged per total Lark Sparrows eggs laid. The greater success of nests built above ground is prob- ably because these are better protected from the elements and from predation. 306 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 1 Success of Parasitized and Non-parasitized Nests Nest Height ( Meters ) Cowbird E,ggs Parasitized Hosts Fledged Non-parasitized Cowbirds Fledged Host Eggs Eggs Fledged 1 ground 1 0 3 0 2 ground 1 0 3 0 3 ground 1 0 3 0 4 ground 3 0 5 ground 1 1 3 3 6 ground 4 0 7 ground 1 0 4 0 8 ground 1 0 4 0 9 1.22 4 3 10 1.83 4 3 11 1.22 1 1 3 3 12 ground 4 4 13 0.74 4 0 14 ground 4 0 15 1.02 4 3 16 1.81 4 4 17 3.66 4 0 18 4.58 1 1 3 1 19 3.96 2 0 3 0 20 1.94 4 4 21 1.52 2 0 4 0 22 ground 1 0 3 2 23 2.44 2 0 4 0 24 6.10 2 0 3 0 25 1.52 2 2 26 5.04 4 3 27 1.52 3 0 28 1.52 2 2 29 1.22 1 0 2 0 30 1.22 4 4 31 0.92 3 9 32 1.22 4 0 33 2.14 1 ? 1 9 Totals 19 3 46 9 65 32 Though I had no direct evidence of predation by snakes, populations of black rat snakes (Elaphe obsolela) and blue racers {Coluber constrictor) were known to be high in the study area during the time of the study. Of the nests under observation, 38.7 per cent were preyed upon and 16.1 per cent were abandoned George A. Newman LARK SPARROW NESTING SUCCESS 307 for causes other than predation. Four of the nests which were preyed upon W'ere disrupted, indicating predation by mammals. Eight other nests were not disrupted, indicating that snakes may have been responsible for the predation. COWBIRD PARASITISM Fifteen of 33 (45.5 per cent) nests were parasitized by the Brown-headed Cowbird (Table 1). Wiens (1963) reported an incidence of 19.0 per cent of cowbird parasitism upon Lark Sparrows in the southern Oklahoma region for the years 1956, 1960, and 1961, based on a total of 21 nests. Of 30 incidences of parasitism reported by Friedmann, only two are known to have successfully fledged young cowbirds. Three out of 14 nests in this study are known to have fledged cowbirds. Of 18 cowbird eggs laid, 33.4 per cent hatched and only 15.8 per cent of the young were successful in leaving the nest. Forty-five host eggs were laid in the same 14 parasitized nests; 17 (37.8 per cent) eggs hatched and 9 (20.0 per cent) young fledged. A total of 58 eggs were laid in 16 non-parasitized nests; 42 (72.4 per cent) of these eggs hatched and 32 (55.2 per cent) young successfully left the nest. This cowbird parasitism was substantially greater among Lark Sparrows than had been previously recorded. The absence of the Bell’s Vireo { Vireo bellii), a common host species of the cowbird (Sutton, 1967), might have caused a shift in parasitism to a less frequent host species, i.e. the Lark Spar- row. Bell’s Vireo has in the past been a relatively common species of the study area. Of 11 ground nests, 7 (63.6 per cent) were parasitized, whereas, 8 out of 22 (36.4 per cent) of the “above ground” nests were parasitized. The ground nests on pasture land were probably more easily accessible to cowbirds than those nests built in trees and shrubs, and there were larger numbers of cow- birds in the pasture land than there were in the other nesting areas. Egg-laying by Lark Sparrows was at its greatest peak during the second week in June (Fig. 3). Cowbirds laid their greatest numbers of eggs during the first two weeks of June and the first week of July. The latest date for a cowbird egg being laid during this study was 5 July. Sutton (1967) records the latest date for egg laying by cowbirds in Marshall County as 3 July. Dur- ing the second week of July, after cowbird egg-laying had ceased, egg-laying by Lark Sparrows reached another peak. Baepler (1968) states that good evidence for douhle-hroodedness in the Lark Sparrow is lacking and it is his conclusion that douhle-hroodedness probably does not occur in this species. On 26 June I observed an adult Lark Sparrow feed a young Lark Sparrow on a telephone wire. This same adult was actively building nest 22 between feedings of the young bird. Although this is not 308 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 WEEKLY INTERVALS Fig. 3. Number of eggs laid by Lark Sparrows and Cowbirds in weekly intervals from 25 May 1968, to 19 July 1968. definite proof of a second brood, it is evidence in favor of two broods being raised by the same Lark Sparrow. This points out the need for careful inves- tigations using color-banded birds to clear up the question of double-brooded- ness in this species. Evidence presented in this paper does indicate that late broods, whether they he second broods or second attempts, do encounter little or no parasitism by the Brown-headed Cowhird. SUMMARY Data were collected on 33 active Lark Sparrow nests from 7 June 1968, to 1 August 1968 in the vicinity of the University of Oklahoma Biological Station. Parasitism of Lark Spar- rows was greater than had previously been reported. A comparison of the success of para- sitized versus non-parasitized nests is presented. Egg laying dates for Lark Sparrows and Cowbirds are presented and analyzed. General nesting site data is presented along with a detailed description of three unusual nest sites. Notes on predation are also given. (fcorge A. Newman LARK SPARROW NESTING SUCCESS 309 ACKNOWLEDGMENTS I am grateful to Dr. George M. Sutton for his guidance and encouragement during this study. I would also like to thank Dr. Carl D. Riggs, Director of the University of Okla- homa Biological Station, and Assistant Director Dr. Loren G. Hill for granting me the opportunity to assist at the biological station during the summer of 1968. Mr. Freeman Thomas gave valuable assistance to me in the identification of plants. LITERATURE CITED Raepler. D. H. 1968. In, A. C. Bent, Life histories of North American cardinals, gros- beaks, huntings, towhees, finches, sparrows, and allies. U. S. Natl. Mus. Bull., 237: 886-902. Friedmann, H. 1963. Host relations of the parasitic cowbirds. U. S. Natl. Mus. Bull., 233. Sutton, G. M. 1967. Oklahoma birds. University of Oklahoma Press, Norman. Wiens, J. A. 1963. Aspects of cowhird parasitism in Southern Oklahoma. Wilson Bull., 75:130-139. DEPARTMENT OF BIOLOGY, HARDIN-SIMMONS UNIVERSITY, ABILENE, TEXAS 79601. 23 OCTOBER 1968. ANNOUNCEMENT A collaborative program to study the migration of the Whistling Swan involving The Johns Hopkins University, the Canadian Wildlife Service, the U.S. Fish & Wildlife Service, the U.S. Air Force, and State and Provincial game agencies has lieen organized. Swans have been marked with colored hands, colored collars, and dyed feathers. Persons who saw marked swans last spring, or who see them this fall should report the details to: Dr. William J. L. Sladen, Johns Hopkins University, 615 N. Wolfe St., Baltimore, Maryland 21205. Those persons who are so located as to see large numbers of swans in migration might well contact Dr. Sladen for report forms and details about the color marking scheme. DUST-BATHING SITES SELECTED BY RUFFED GROUSE Dale Hein An opportunity to study the preferences of Ruffed Grouse ( Bonasa umbel- lus) for dust-bathing sites occurred near Highlands, Macon County, North Carolina. During June 1968, grouse commonly dust bathed along an abandoned logging road which wound northeastward for 2.5 km from Wild- cat Cliffs. The straight-line distance traversed was 1.4 km. The trail exposed many possible dusting substrates — litter and duff areas, decaying logs and stumps, silty sediments, clay banks, gravelly areas where intermittent watercourses crossed the trail, and numerous bare soils obviously different in texture, structure, and color. The hilly topography and the wind- ing trail also presented variations in site factors in addition to substrate types. The trail provided virtually the only opening in dense second growth, mesic vegetation in various intermediate stages of succession (Fig. 1). Important species of the discontinuous canopy included red maple {Acer rubrurn), cherry birch [ Betula lenta), tulip poplar {Liriodendron tulipifera) , and white pine [Pinus strobus) . The dense understory was characterized by thickets of great rhododendron {Rhododendron maximum) interspersed with less abundant species such as flowering dogwood [Cornus florida) . In many places the old road was reduced to a narrow trail winding through brambles {Rubus sp. ) . Ferns and herbs such as galax {Galax aphylla) covered much of the ground away from the trail. Mean elevation of the study area is 1200 m. Annual pre- cipitation averages 200 cm, and the mean June temperature is 19°C. Odum (1950) gave a succinct description of the avifauna and plant communities of the Highlands Plateau, which includes this study area. In a monumental study of Ruffed Grouse in New York, Bump et al. (1947: 271 ) found that dust baths were located in any spot offering suitable material and receiving the sun’s rays during some portion of the day. The material utilized was varied, the primary requirement being looseness and dryness. Dry, rotten wood of old stumps and logs was most frequently used with fine, dry earth a close second. In northern New York fine sand was commonly favored. Dust bathing by Ruffed Grouse is generally believed to be a maintenance ac- tivity for feather care and riddance of ectoparasites (Edminster, 1954:204; Forbush and May, 1955:137 ). METHODS Two grouse were flushed from dust bathing sites when I first walked the trail during midafternoon on 1 June. Two grouse were flushed from different dusting sites on 6 June, and locations and genera] site characteristics were noted for 20 dusting scrapes, some ap- 310 Dale Hein GROUSE DUST-BATHING SITES 311 Fig. 1. Typical dust-bathing site of Ruffed Grouse near Highlands, North Carolina, June 1968. A fresh dusting scrape is located in front of the binoculars. parently older and used more than others. Grouse scrapes were easily identified by their size and often by presence of grouse feathers and droppings. There was no evidence of dust bathing by any other species larger than the Brown Thrasher (Toxostoma rufum) . Existing scrapes were obliterated by more than 9 cm of rain on 8 June. Cloudy, humid weather and light rains on 9 and 12 June kept the soil surfaces damp and no dusting scrapes were found along the trail on 12 June. However, 13 and 14 June were warm and sunny with low humidity. I anticipated that most grouse would use the newly dried soils on the afternoon of 14 June, after a week without dusting, and 14 new scrapes were found and examined in detail on 15 June during 09:00-13:00. Aspect, exposure, adjacent vegetation, and distance to closest dusting scrape was noted for each of the 14 scrapes. Maximum depth and rim-to-rim distances of longest and short- est axes were measured. At each scrape 200 cc of substrate was collected from the rim and surface of the dusting depression. Each of the 14 samples was oven-dried, weighed, and shaken for 30 minutes through six sieves in the U. S. Standard Sieve Series, after which each separate was weighed. The seven separates approximated the classification of soil particles established by the Department of Agriculture (Lyon et ah, 1952:46), except the silt and clay separates were combined. Bulk density, particle density, and color were also recorded for each sample. A large rock was placed in each scrape after the sulistrate sample was collected. The trail was checked for new scrapes on 16 June, and a final check of new and old scrapes was made on 22 June. 312 THE WILSON BULLETIN September 1970 Vol. 82. No. 3 Table 1 Textures of Soil Used by Ruffed Grouse for Dust Bathing near Highlands, North Carolina, 15 June 1968 Percent of sample in each soil separate Sami^le Gravel Very coarse sand Coarse sand Medium sand Fine sand Very- fine sand Silt and clay Coarsest of 14 8 18 30 25 12 4 3 Average of 14 6 9 24 29 19 8 5 Finest of 14 3 8 21 27 21 12 8 RESULTS The dimensions and locations of the 14 dusting scrapes were similar. The average size of the scrapes was 30 X 25 X 3.2 cm. Extreme rim-to-rim dis- tances were 45 and 18 cm, and depths ranged from 1 to 5 cm. In three cases, the distance between scrapes was less than 2 m; all other intervals were more than 40 m. Five scrapes were overhung by brambles, and all others were less than 2 m from thick cover. Four scrapes were in relatively straight sections of the trail, while 10 were on the outside (greater) curve of a bend in the old road. Two sites had an east aspect, and 12 had west or southwest aspects with less than 15° slope. Textures of soils in the dusting scrapes were remarkably similar. Approxi- mately 90 per cent of each sample was comprised of various classes of sands (Table 1). The coarsest sample contained 8 per cent gravel (particles greater than 2 mm in diameter), and the finest sample contained 8 per cent silt-clay (particles less than 0.05 mm diameter). The bulk densities of the 14 samples averaged 1.2, and the particle density averaged 2.6. Both figures were in the lower range of normal values for sandy soils (Lyon et ah, 1952:56-59). Bulk densities would have been higher in un- disturbed areas adjacent to the dusting scrapes. Soil colors were compared with Chapman’s (1914:26-27) color chart. Closest matches for the 14 samples were 5 ochraceous buff, 3 brownish gray, 3 ashy, and 1 each grayish brown, brownish ashy, and pearl gray. Colors in the chart of Palmer ( 1962:4-5) did not match soil colors as well; smoke gray, huffy brown, and cinnamon were chart colors resembling the soil colors. Approximately 24 hours after the collection of the soil samples and the placing of a large rock in each scrape, the trail was rechecked, and seven new scrapes were found. Three were within 2 m of an old scrape, and four were 8, 20, 20 and 70 m from an old scrape. All were at sites similar to those sam- Dale Hein GROUSE DUST-BATHING SITES 313 pled. When the trail was last checked 6 days later, 11 grouse dusting scrapes were identified excluding the 14 sampled and destroyed earlier. All were simi- lar in appearance and location to those described earlier. DISCUSSION Four factors were evidently important in determining location of dust bath- ing sites: (1) sand substrate, (2) exposure to the sun, (3) proximity of dense cover, and (4) maximum visibility for the grouse of clear routes of approach to the site. Thus, the typical scrape was on the north and outside of a curve in the trail, which provided the best view in both directions. The site was over- hung by brambles or adjacent to similar escape cover. The substrate was sand, and the site sloped slightly providing a south aspect. Obviously these factors maximized protection from predators while dust bathing and provided dry, loose dusting material. In this area of high rainfall and frequent heavy dew, many substrates, such as rotting logs and litter, were seldom dry enough for dusting material. Soil colors at dusting sites were generally similar to colors predominating in Chapman’s (1914:273) description of Ruffed Grouse. One-third of the sam- ples were ochraceous buff, the color Chapman used to describe throat, breast, and some variegating of the back. However, the data were insufficient to persuasively indicate that grouse selected dusting material of certain colors. Although the sample of sites reported here is small, they were remarkably uniform. During June cursory examination of more than 20 other grouse dust- ing sites in other parts of the Highlands Plateau agreed with the detailed ex- amination of 14 sites described. Some unanswered questions include (1) what determines frequency of dust bathing by an individual bird, (2) does more than one bird use the same scrape, and ( 3 ) how important are suitable dusting sites in the habitat require- ments of the species? SUMMARY Site factors and soil characters associated with dust l)ath locations of Ruffed Grouse were investigated near Highlands, North Carolina. Important factors were those which combined to provide dry, loose substrate and safety from predators. ACKNOWLEDGMENTS This research was aided by the National Science Foundation granl-in-aid, N.SF GR 2496, made to the Highlands Biological Station and administered by Dr. Thelma Howell, Execu- tive Director of the station. LITERATURE CITED Bump, G., R. W. Darrow, F. C. Edminster, anu W. F. Crissey. 1947. The Ruffed Grouse: life history, propagation, management. New York State Conservation Dept. 314 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Chapman, F. M. 1914. Handbook of birds of Eastern North America. Revised ed. D. Appleton and Co., New York. Edminster, F. 1954. American game birds of field and forest. Charles Scribner’s Sons, New York. Forbusii, E. H., and J. B. May. 1955. A natural history of American birds of eastern and central North America. Houghton Mifflin Co., Boston. Lyon, T. L., H. 0. Buckman, and N. C. Brady. 1952. The nature and properties of soils. Macmillan Co., New York. Odum, E. P. 1950. Bird populations of the Highlands (North Carolina) Plateau in rela- tion to plant succession and avian invasion. Ecology, 31:587-605. Palmer, R. S. 1962. Handbook of North American birds. Vol. 1. Yale Univ. Press, New Haven, Connecticut. DEPARTMENT OF FISHERY AND WILDLIFE BIOLOGY, COLORADO STATE UNIVERSITY, FORT COLLINS, COLORADO 80521, 3 JANUARY 1969. PUBLICATION NOTES AND NOTICES Birds of Asia. Illustrations from the lithographs of John Gould. Text by Abram Rutgers. Taplinger Publishing Company, New York, 1969: 71-4 X 9% in., 321 pp., 160 col. pis. $15.00. This is the third in the series, after “Birds of Europe” (1966) and “Bird of Australia” • 1967), reproducing the lithographs of Gould with text hy Rutgers. Comments made in the review of the first book (see Wilson Bull., 79:255-256, 1967) and in the notice of the second (Wilson Bull., 80:247) are applicable to this volume which is practically identical in format and presentation. — O.S.P. Histoire Naturelledu Code, Alca torda, L., dans le golfe Saint-Laurent, Province de Quebec, Canada. Par Jean Bedard. Etude du Service Canadien de la Faune No. 7, Ministere des Affaires Indiennes et due Nord Canadien, Ottawa, 1969: 79 pp., 40 figs., 11 tables. $1.25. An English edition of this extensive study of the Razorbill is scheduled for publication in 1970. Catalogus Faunae Graeciae. Pars 2, Aves. By W. Bauer, 0. v. Helversen, M. Hodge, and J. Martens. Privately published, 1%9: 203 pp., 2 maps. $4.75. (Copies may be purchased from Max E. Hodge, 6345 Western Avenue, Washington, D.C.) In German. A more comprehensive “Birds of Greece,” to be published in English, is in preparation. Las Aves de Tikal. By Frank B. Smithe. Litografia Byron Zadik y Cia., Guatemala, C.A., 1969. Soft Cover Edition: .$3. (Obtainable from the Asociacion Tikal, Avenida de las Americas 6-19, Zona 14, Guatemala City, Guatemala, C.A.) A Spanish language edition of Smithe's “Birds of Tikal,” 1966 (for review see Land, Wilson Bull. 80:244-246, 1%8). All profits from the sale of this edition go to the Asociacion Tikal, a non-profit organization which supports local interest in conservation and archaeology in Guatemala. OBSERVATIONS ON THE BREEDING BIOLOGY OF THE VERMILION FLYCATCHER IN ARIZONA Walter Kingsley Taylor and Hugh Hanson During the period 6 April to 2 June 1967 we made observations on three nesting pairs of Vermilion Flycatchers (Pyrocephalus rubinus), two of which had second broods. Two additional pairs were in the area as well as a territory holding male, of much lighter coloration, that was believed to have never mated. None of the flycatchers were marked for individual identifica- tion. Our observations were made in a well-developed mesquite {Prosopis jiili- flora ) floodplain woodland locally known as Coon’s Bluff Recreational Area, in Tonto National Forest, approximately 16 miles northeast of Mesa, Maricopa County, Arizona. Typical Lower Sonoran desert vegetation occupies adjacent upland regions. HOSTILE BEHAVIOR A few instances of prolonged conflict and aggressiveness between two fly- catchers were observed. On 8 April at 07 :30 the male of pair one and the light-colored unmated male chased each other for approximately 10 minutes. The mated male, evidently defending his territory, was the more aggressive in- dividual. He made several short pursuit flights at the unmated male who in- variably retreated. At the termination of each chase, the two males perched 10 to 20 feet apart. Their crown feathers were erect. The tail was spread, hanging downward, and was frequently flicked. Each emitted a loud, sharp peent note (see below). Occasional loud bill snapping sounds were produced, but the Gape Display mentioned by Smith (1967) was not seen. Evidently, the light-colored male was both the intruder and loser. Once a male flycatcher terminated a flight display to chase a Violet-green Swallow {Tachycineta thalassina) in flight nearby. Lucy’s Warbler [V enni- vora luciae ) was driven from the nest site by both sexes on three occasions. Once a male flycatcher chased a female Audubon’s Warbler [Dendroica audii- boni) from the nest tree. Brandt (1951) cited an incident of a male flycatcher attacking a male House Finch {Carpodaciis mexicanus) , but we found a pair of House Finches and flycatchers nesting in the same mesquite. On another occasion, however, the male flycatcher of a different pair chased a singing male finch from a nest with nestling flycatchers. VOICE Four distinct vocalizations were recognized. The primary functional sig- nificance of each is believed to be understood. 315 316 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Song — The song is produced repeatedly by the male during the elaborate display flight. The song sounds like the words pur-reet with the first portion consisting of rapid repeated rolling notes. On infrequent occasions, perched males gave the same or at least portions of a similar song throughout the day. The song is produced by mated and unmated males. Peent note — This is the typical call of the species and is commonly produced by both sexes. Each peent note is sharp sounding and loudly or softly given, depending upon the circumstances. It was produced by disputing males and by both sexes during displacement activities. In these circumstances, the in- dividual notes were loud. The male used this call when he arrived to feed the incubating or brooding female. In these instances, the individual notes were not nearly as loud as during the disputes. Feeding notes — These notes sounded as softly, quickly produced piks given by adults when feeding nestlings and probably alert the nestlings of the parent’s presence. Nestling notes — These peeping sounds were produced by disturbed nestlings. They were given at a rapid rate and are quite loud from the first day of hatching. NESTING BIOLOGY Nest building — The female built the nest but the male on several occasions accompanied her to the building site. A nest was found under construction on 6 April. Two days later the female was actively building on the structure. In another nest located 8 April shortly after construction had begun, an addi- tional four days elapsed before the first egg was laid. Newly-constructed nests were used in the two cases of second nestings. Materials from one of the first nest were used in building the second structure. Cluteh size and egg-laying — Lour clutches of three eggs and one of two eggs were observed. In two nests, the eggs were not laid on consecutive days. Incubation period — Bent (1942) stated the incubation period as about 12 days and Wheelock (1904) gave 12.5 days required for the incubation of three eggs. In three nests we observed the incubation period (elapsed time between laying of the last egg to hatching of that egg) was 14 to 15 days. The clutches were incubated during late April. Incubation behavior — Incubation was performed by the female, but, the male of one pair on two occasions entered the nest for less than one minute. Once the female chased the male away shortly after he entered the nest. In both instances, the male definitely did not remain in the nest long enough to incubate nor could we see any evidence of an incubation patch on the male. The presence of this structure could easily be detected on the female. Bendire (see Bent, 1942) stated that “the male assists [in incubation] to some extent, TaNlor and Hanson VERMILION FLYCATCHER BREEDING 317 as I have on two occasions seen one sitting on the eggs.” Possibly his ohserva- tions are comparable to our observations described above. In two pairs the female spent an appreciable amount of time on the nest before the clutch was completed. The length of time on the nest during these periods was typically short, but frequent. Davis, Fisler, and Davis (1963) found that the female Western Flycatcher [Empidonax dijjicilis) spent con- siderable time on the nest before the clutch was completed. During incubation and brooding, the males of pairs one and three brought food to the incubating female on the nest. This behavior never occurred in pair two during 210 minutes of observations spaced throughout incubation. The male of pair two, however, like the other males, fed the female off the nest. Feeding of the female by the male occurred with a slightly higher fre- quency on than off the nest. The male usually perched a short distance from the nest when he came to feed the female. He then gave peent notes which obviously announced his presence; he would spread his tail as it hung down and suddenly fly to the female. The male quickly deposited the food into the female’s mouth and flew away. Sometimes the female gave subdued peent notes when the male appeared with food. She usually remained on the nest after these feedings; occasionally she left with the male. At times, the male did not go to the nest and the female flew to him and took the food. Copula- tion was frequently observed after these feedings. Twice the male with food flew straight to the nest while the female was absent. On both occasions, the female suddenly appeared and flew to the male at the nest. Both birds fluttered about as the male fed the female. After these feedings, they flew from the nest. The female never begged for food during any of these feedings. Idle female often brought nesting materials when returning to incubate. She typically went to and from the nest alone, silently, and in a direct manner. She frequently terminated attentive periods to pursue nearby flying insects. The female’s time spent off the nest was devoted to hawking insects near the nesting area. In 424 minutes observing pair three, with nestlings 1 and 3 days old, the female had 43 attentive periods ranging from 20 seconds to 17.5 minutes. Ihe mean time spent on the nest was 6.4 minutes and the percentage of attentive- ness was 63. The mean inattentiveness through a total of 3o inattentive periods for this female was 4.8 minutes and ranged 20 seconds to 15 minutes. During 110 minutes observing another nest with one nestling that hatched that morn- ing, the female had eight attentive periods ranging from 1 to 26 minutes. Ihe mean time spent on the nest was 11 minutes and the percentage of altenlive- ness was 80. The mean inattentiveness through a total of seven inattentive periods for this same female was 3.1 and ranged 1 to 6 minutes. One incuhat- 318 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 ing female remained on the nest for 39 consecutive minutes. This was the longest period any incubating or brooding female spent on the nest. The male did not feed the female during the 39-minute period. The female of pair three nested about five feet from the edge of a sandy road frequently used on weekends by hikers and passing automobiles. During early incubation, a person or dog walking by the tree caused the female to immediately leave the nest; however, she remained on the nest if a car passed. After heavy incubation began, passing individuals and dogs seldom disrupted her incubation activities. Hatchings — In one nest with three eggs, hatching extended for two days. The third egg did not hatch and remained in the nest with the two nestlings for at least five days. The nestling flycatcher at hatching has tufts of creamy-colored feathers in various areas of the dorsal portion of the body. The nestlings characteristically contain a considerable amount of blackish pigment, especially on the dorsum. Dawson (1923) said “the chicks are black for a few days after hatching, with some outcropping of white down.” We, however, cannot agree entirely with Wheelock’s (1904) statement that the young flycatcher at hatching is salmon- pinkish in color. Two nestlings weighed 1.1 and 1.5 grams on the day of hatching. Parental care of the nestlings — Both sexes fed the nestlings. The male and female fed the young 11 and 8 times, respectively, during 185 minutes at one nest with two nestlings, the oldest two days of age. The female continued to brood the young in the early stages of nest life. The male often fed the brood- ing female in the same manner as during incubation. She would eat or pass the food to the nestlings by raising up in the nest giving the feeding notes. The frequency of feedings of the female by the male diminished after the young were present. In one nest with three nestlings, the female and the male made 6 and 4 trips, respectively, during 64 minutes of observation in the late morning. In another nest, the female made only two feedings in 110 minutes, to the one nestling that had hatched that morning. Both feedings occurred as the female began an attentive period. The male flycatcher did not feed the nestlings or the female during this period. Both sexes removed fecal sacs. At a nest with two young (0 and 2 days old ) , the male and female each removed and ate three fecal sacs during 122 minutes of observations. Observations of the later phases of the nesting activities were limited since two of the first nests were disrupted by unknown causes. One nest had its contents (two well-developed nestlings and one unhatched egg) completely removed, although the structure remained in perfect condition. The other Taylor and Hanson VERMILION FLYCATCHER BREEDING 319 nest was abandoned for unknown cause the day two eggs hatched. The young lay dead in the nest along with an unhatched egg, hut the adults were observed in the area. A second nest of the pair was under construction 6 May, four days after discovery of the dead young. SUMMARY A study was made of breeding activities of Vermilion Flycatchers in a mesciuite wood- land, near Mesa, Maricopa County, Arizona. Hostile behavior in territorial defense is described. Four distinct vocalizations were recognized; the song is a function of the male. Data on nest building, clutch size, egg-laying, incubation period and behavior, hatching, and parental care of the nestlings are given. LITERATURE CITED Bent, A. C. 1942. Life histories of North American flycatchers, larks, swallows, and their allies. U. S. Natl. Mus. Bulb, 179. Brandt, H. 1951. Arizona and its bird life. The Bird Research Foundation, Cleveland. Davis, J., G. F. Fisler, and B. S. Davis. 1963. The breeding biology of the Western Flycatcher. Condor, 65:337-382. D.\wson, W. L. 1923. The birds of California. Vol. II. South Moulton Co., San Diego. Smith, W. J. 1967. Displays of the Vermilion Flycatcher {Pyrocephalus ruhinus) . Condor, 69:601-605. Wheelock, I. G. 1904. Birds of California. A. C. McClurg and Co., Chicago. DEPARTMENT OF ZOOLOGY, ARIZONA STATE UNIVERSITY, TEMPE, ARIZONA. (PRES- ENT ADDRESS : (WKT ) DEPARTMENT OF BIOLOGY, FLORIDA TECHNOLOGICAL UNIVERSITY, ORLANDO, FLORIDA), 12 AUGUST 1968. PUBLICATION NOTES AND NOTICES Identification Guide to European Passerines. By Lars Svensson. Naturhistoriska Riksmuseet, Stockholm, Sweden. 1970: 4 X 7% in. 152 pp. many text figs. 15 Swedish Kroner. A pocket guide to identification, sexing, and aging of birds for banders, and those studying museum skins. Approximately 15 North American species are included. Birds of the Bozeman Latilong. By P. D. Skaar. Privately published, 1969: 8% X IL 132 pp., mimeo, no price given. (Obtainable from P. D. Skaar, 501 S. Third St., Bozeman, Montana. An annotated list of 277 species listed between 45° and 46° N latitude and 111° and 112° W longitude (latilong). California Birds — (A new periodical). Published by the California Field Ornithologists, Clifford R. Lyons, Treasurer, 6424 Mt. Adelliert Drive, San Diego, California 92111. Annual dues $5. This is a most welcome addition to the list of state ornithological journals for a state with a large body of active bird students. Volume 1, No. 1, 1970 contains an updated checklist of the Birds of California. GENERAL NOTES Additional notes on the plumages of the Redhead (Aythya attiericaria) — During my study of the plumages of Redheads (Weller, Wilson Bull, 69:5-38, 1957), several confusing observations were made on the plumages of young males in the fall. These probably were not properly interpreted, and this note is a re-evaluation of my earlier study in the light of observations by Humphrey and Parkes (Auk, 76:1-31, 1959), and a report of a brief experiment designed to better appraise the early plumages of male Redheads. My earlier comments on the young male (1957:23) were: “Many males have brownish- red feathers in their lores and cheeks at eight weeks of age; these are present in all males at nine weeks”. . . . “At 14 weeks, the male’s head is more chestnut than huffy brown. . . The latter plumage is illustrated in the color plate facing page 5, which also shows the accjuisition of post-juvenal male plumage in the chest, sides and scapulars. The color of the head in this plumage more nearly resembles that of adult males in “eclipse” plumage than of adult males in nuptial plumage. At that time I assumed that the early feathers of the nuptial plumage merely were less definitive in color and size. Because I was unable to observe these changes through- out the winter, the transition was less noticeable. A comparison of skins from birds taken in fall and spring shows a rather marked difference in brilliance of the red color, purplish iridescence and length of the head feathers. In an attempt to better analyze the transition from the tan-headed juvenile to the red- headed adult plumage and to determine the status of intermediate plumages in females, detailed observations were made on eight captives during the fall of 1966; five were males, three were females. These birds were obtained from the Northern Prairie Wildlife Center of the Bureau of Sport Fisheries and Wildlife for which I am indebted to Harvey Nelson, Director, and Charles Dane, Wildlife Biologist. Arnold 0. Haugen transported the birds from Jamestown, North Dakota, to Ames, Iowa, where the birds were housed outdoors. Thanks are due Eldon Greij, Loren Bates, and Robert Bergman for assistance in care of birds and in recording data. On receipt cn 8 October, birds were about 13 weeks old. All were examined for plumage status and molt, and selected feathers or tracts were clipped for identification. Although clipping did not permit identification of all feathers of a particular tract, the presence or aljsence of these feathers aided in determining the number of plumages involved. To quantify the degree of molt, intensity was scored on a scale of: 0 (none), 1 (little) or 2 (much). Each feather tract was examined by lifting the feathers with a forceps. When less than one fourth of these probes showed new feathers, molt was recorded as little. When more than one fourth showed new feathers, it was termed much. Tracts were examined approximately monthly from 8 October 1966 to 27 May 1967. Data from one male are deleted because its chronology of molt was markedly delayed. All birds received were in dominantly juvenal plumage but were involved in a post- juvenal molt of the entire head and much of the body. This molt continued through December, hut there was little or no molt in most birds in January (Fig. 1). Another molt from late February through March involved both the head and body of females hut mainly the body of males. Then the eclipse plumage started to develop in males in early 1 Journal Paper No. J-6122 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. I’roject No. 1.504. 320 Se]Jlcmber 1970 Vol. 82, No. 3 GENERAL NOTES 321 Fig. 1. Postjuvenal molt indices for four male and three female Redheads. to mid-April, presumably because of the lack of conditions that would produce a normal breeding cycle. In addition, some infrared lights used in January may have induced early plumage development. This early molt in males made it difficult to interpret the third plumage acquired in early spring by females. Clipping was done either when birds were received in October or during mid- January when their first molt ceased. The most significant results were from birds mass- clipped with a scissors in each feather tract. The following individual examples help to explain the curves that show an average of all molt of males and females (Fig. 1) and the curves for selected areas (Fig. 2). Males. — It appears that males actually have two head molts following the juvenal plumage and that both are completed by early January concurrent with the body molt. The first head molt occurs in October and produces brownish-red head feathers longer than those of the juvenal plumage but which lack the length, color, and iridescence of those that develop in late November and early December. Male No. 86 was clipped on 8 October, and all clippings on the head were gone by 3 December. Head molt continued in January. These molts are so continuous that no stopping points are available to use as a base to appraise the extent of the molt or number of plumages. Males Nos. 78 and 92 both were mass-clipped on 29 January following completion of the extensive double head molt. Both still had evidence of clipping on the head in early April suggesting that few additional red feathers developed. Thereafter, brown feathers of the eclipse plumage developed on the head and body and molt continued through May. The juvenal body plumage and tail were replaced with a somewhat dull but adult- like plumage by late December during the period when two head molts occurred. Some clipped body feathers of male No. 86 were retained from 8 October until 18 February and clipped mantle feathers existed until late May, hut these could have been feathers of the first non-nuptial plumage. The second period of body molt in late February and March was much less wide- spread than in females and involved mostly the scapulars and side (Fig. 2). Whether this was a complete renewal of the body plumage (into nuptial) or a partial body molt 322 THE WILSON BULLETIN Septeml)er 1970 Vol. 82, No. 3 cf 9 started in fall and finished in the spring is uncertain but there is no conspicuous change in body color during this period. Females. — All feather tracts of female No. 77 were clipped on 8 October. By 3 December, all clipped feathers had been replaced on the head, chest and side but a few were present in the scapulars. All were gone by 21 January, but the posterior one-third of the belly still appeared to be dominantly juvenal. A few feathers on all tracts of female No. 93 were marked and clipped on 8 October. These were gone by 3 December, and she completed a major molt on the head, neck and entire body by 7 January; at that time she was clipped again. Another molt started subsequently and the clipped head feathers were gone by 17 March; most clipped body feathers were replaced by 1 April except those of the mantle. These two observations and Figures 1 and 2 suggest the following pattern in females: The juvenal head and body plumage is replaced by the first non-nuptial plumage by early January but some juvenal feathers may persist on the lower belly and venter. Possibly the timing of these plumages was influenced by captivity. A second molt oc- curred in late February and early March and presumably represents the pre-nuptial molt of the head, side and scapulars. The female became more rufous brown at this time as noted in wild birds (Weller, 1957:26). Subsequent molt in April and May was assumed to be tbe non-nuptial plumage but modifications of timing make the normality of this uncertain. September 1970 \ ol. 82, No. 3 GENERAL NOTES 323 This sequence needs further study in both young and adult females. It is possible that a transient plumage occurs in females as it does in males hut it could not he discerned from feather colors. Oring (Auk, 85:355-380, 1968) found a brief first non-nuptial (basic) plumage in autumn, nuptial (alternate) in winter and early spring, and a second non-nuptial in the early summer pre-nesting period of hen Gadwalls (Anns strepera) . This would subsequently result in a pattern in adult females which is comparable to males except that females acquire the non-nuptial prior to nesting whereas males acquire it after breeding ( R. Palmer, pers. comm.). Too little data are available in this study to draw conclusions on complete sequences of plumages, hut there is little question that the first non-nuptial plumage is present in both sexes. New techniques are needed to study the extent of these plumages in different tracts (and perhaps within tracts), the apparent inconsistency in number of feather generations per follicle, and the overlap of these plumages. — Milton W. Weller, Department of Zoology and Entomology, Iowa State University, Ames, Iowa 50010, 20 January 1969. Observations on premigratory movements of hand-reared Mallards. — In July and August of 1968 a total of 301 four to five-week old Mallard (Anas platyrhynchos) ducklings were released in southern Wisconsin. These birds were hatched at the Delta Waterfowl Research Station in Manitoba, Canada from eggs collected from a captive wild flock of Mallards. An analysis of the first fall band returns of these released juveniles shows that 18 were shot between 5 October and 26 October. During this premigratory period 15 of the recoveries were north of the release site and only three south of it (Fig. 1). This northward movement must have taken place sometime between the onset of flying in these young birds (about the second or third week in August) and the time when they Fig. 1. 324 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 were shot. The average distance travelled hy these birds during this time interval was 51.3 miles. Bellrose (Bird-Banding, 29:75-90, 1958) found that wild Mallards released on clear days in unfamiliar terrain headed north no matter what time of the year they were released. The data reported here support these findings. They also indicate that this phenomenon may he shown hy hand-reared birds as well as pure wild Mallards, and that this may he a long distance as well as an immediate orientation. — James J. Zoiirer, Department of Wildlife Ecology, University of Wisconsin, Madison, Wisconsin. 2 August 1969. Trumpeter Swan carrying young. — This observation describes a Trumpeter Swan ( Olor buccinator) cygnet riding on the hack of an adult. Although Delacour and Mayr (1945) as quoted in Banko (The Trumpeter Swan, its history, habits and population in the United States. N. Amer. Fauna, No. 63, 1960) state that Mute (Cygnus olor) and Black-necked Swans [Cygnus melancoriphus) generally carry young on the hack and other swans have this habit, Banko added that this behavior has not been reported in Trumpeter Swans. Trumpeter Swans were transplanted from Red Rock Lakes National Wildlife Refuge. Montana to Lacreek National Wildlife Refuge, South Dakota in 1960 (Monnie, J. Wildl. M gmt. 30:691-696, 1966). Two cygnets were produced in 1963 and reproduction increased to 15 cygnets reaching flight age in 1968. Fig. 1. Trumpeter Swan carrying cygnet. September 1970 Vol. 82, No. 3 GENERAL NOTES 325 On 8 June 1969 at 18:30 a pair of Trumpeter Swans with five cygnets was surprised in a narrow borrow ditch adjoining a 531-acre marsh in which the pair had nested. Cygnets swam between the adults as the brood progressed down the ditch. Soon after, one cygnet swam around to the anterior end of an adult and climbed onto its hack. The cygnet quickly turned around, sat down and began preening. Both adults were alerted to my presence and disregarded the preening cygnet (Fig. 1). Four other cygnets remained in the original swimming position. The swans were motionless in the water watching me or were swimming down the ditch during the next 15 minutes. The riding cygnet continued preening for five minutes and then returned to the other cygnets swimming between the adults. An opening in dense cattail provided an escape route allowing the brood to swim out of view a few minutes later. — Donald A. Hammeh, Lacreek National Wildlife Refuge, Marlin, South Dakota, 2 September 1969. Notes on the foods of juvenile Black-bellied Tree Ducks. — Studies of waterfowl food habits traditionally emphasize the diet of adult game ducks (cf. Cottam, Tech. Bull. 643, U.S. Dept. Agr., 1939; Martin and Uhler, Res. Kept. 30 (reprinted), U.S. Fish and Wildl. Serv., 1951). Only more recently, however, have the diets of juvenile waterfowl been emphasized in the literature. Chura (Trans. N. Amer. Wildl. Conf. 26:121-134, 1961), for example, described the diet of maturing juvenile mallards (Anas platyrhynchos) . Similarly, Bolen and Forsyth (Wilson Bull. 79:43-49, 1967) reported only the foods of adult Black-Bellied Tree Ducks i Dendrocygna autumnal is) , and until now, even scant records were unavailable for young birds of this species. Individual foods from both the crops and gizzards of two Black-bellied Tree Duck broods were examined volumetrically to determine basic trends in the diets of the young birds. The birds’ ages were estimated from linear measurements of the middle toe, exposed culmen, and tarsus length following criteria developed by Cain (in press). These broods and other tree ducks were collected in 1966 and 1967 at Lake Mathis ( Lake Corpus Christi) in Live Oak and San Patricio Counties, Texas. The foods of five 21-day old ducklings primarily consisted of Echinchloa colonum seeds; this food occurred in all of the gizzards and crops ( 100 per cent frequency within the brood) and with an average volume of 5.4 cc (crops) and 2.5 cc (gizzards). Eclipta alba (= V erbesina alba) seeds occurred in all of the crops and in 40 per cent of the gizzards; its volume was 0.1 cc or less in each case. Animal matter was found only in the crops (100 per cent frequency) and averaged 0.5 cc per bird. The crops and gizzards of six 35-day old ducklings each contained Sagittaria tubers; the average volume for this food was 0.8 cc (gizzards) and 7.0 cc (crops). Trace amounts of Heteranthera dubia seeds occurred in some of these samples. Measureahle amounts of animal matter were again largely limited to the crop samples; the average amount per crop was 0.6 cc. The overall percentages of plant and animal materials in the diets of these broods are compared with similar data for a larger sample of adults in Table 1. The two adults tending the 21-day old brood contained only trace amounts of animal matter whereas the adult collected with the 35-day old brood lacked any evidence of animal food in its digestive tract. The nature of the animal matter seems significant. Specifically, the animal foods taken by the younger brood included insects, spiders, snails iPhysa anatina) , and in one instance, a bivalve (Sphaerium securis) . Of these, only the insects and spiders were 326 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Table 1 Comparison of Overall Plant and Animal Diets from the Crops of Juvenile AND Adult Black-bellied Tree Ducks. Type of Food-Per cent Age Group Plant Animal 21-day brood 91.6 8.4 35-day brood 91.3 8.7 Adults" 94.4 5.6 * Data from Bolen and Forsyth (1967). important foods, each occurring with 100 per cent frequency of occurrence. The insects included 14 families of which most (86 per cent) were primarily terrestrial. Animal matter in tlie 35-day old brood included insects, snails, oligochaets, and single occurrences of an unidentified tick and freshwater shrimp. Nine insect families were represented of which only two (22 per cent) were primarily terrestrial taxa. The incidence of terrestrial insects in the younger brood and the corresponding change to acquatic forms in the older broods suggests that young tree ducks are reluctant to submerge their heads while feeding. Additionally, the older tree duck broed fed heavily on submersed Sagittaria tubers whereas the young birds took plant foods either aerially or floating at the surface. Chura (op. cit.) found that young Mallards are at first hesitant to submerge while feeding and that they accordingly tend to avoid many aquatic invertebrates until their feeding behavior matures further. The few data now available indicate, however, that young Black-bellied Tree Ducks still in downy plumage apparently rely less heavily on animal foods than many other waterfowl species. Several food items were identified with the gracious assistance of Francis M. Uhler and Harold D. Murray. The field work was supported by the Rob and Bessie Welder Wildlife Foundation and the School of Agricultural Sciences, Texas Tech University. — Eric G. Bolen and John J. Beecham, Department of Range and Wildlife Management, Texas Tech University, Lubbock, Texas 79409, 24 June 1969. Successful reconstruction of active Bald Eagle nest. — On 25 June 1969 an active Bald Eagle (Haliaeetus leucocephalus) nest in Itasca County, Minnesota, blew down during a violent rain storm (wind 65 mph). The nest, two 8-week-old eaglets, and the top two meters of the tree fell 18 m to the ground. The tree supporting the nest was a partially dead northern red oak (Quercus rubra) and had served as the nest supporting structure for 16 years. The nest was located 214 m above the forest canopy on the dead portion of the tree and the parent birds had easy access from all directions. The nestlings showed no apparent injuries and were kept for three nights in a make- shift nest box three m above the ground. This nest could not be seen from above the forest canopy. On 27 June an artificial nest was constructed adjacent to the trunk of the original nest tree on a large branch one-third m from the top of the tree. The base of the nest was constructed of six freshly cut poplar poles V/s meters long which were nailed and criss-crossed on top of the branch. A two-meter square piece of 214 cm cbicken wire was then placed on top of this framework. A 1% meter square piece of burlap was then placed over the larger sticks and on top of this were placed smaller Sei»tctiiber 1970 \ ol. 82, No. 3 GENERAL NOTES 327 sticks and decayed woody material from the old nest. Fresh sphagnum moss (Sphagnum spp.) was then placed on top of the entire structure to prevent rain from washing away the woody material. This moss is commonly found in Bald Eagle nests in Minnesota. The eaglets were fed small minnows (Chrosomus spp.) and pieces of yellow perch [Perea, ilavescens) periodically until they were placed in the artificial nest at 08:15 on 28 June. The female parent had flown over the nesting area on 25 and 26 June, hut neither the female nor the male roosted in the area of the fallen nest at night. At 10:38 on 28 June the female flew by the nesting area out of sight of the nest and gave a series of calls. At 12:15 the male parent flew directly over the nest and showed no change in attitude or in normal flight. At 15:30 the female parent flow over the nest and gave a long series of calls while circling the area nine times then left. The male was observed stretching his wings and preening while on an alternate nest 350 m north of the artificial nest. He showed no interest in breeding activities. At 21:00 (20 minutes before sunset) the female returned to a favored perch near the artificial nest and was harassed by a Broad-winged Hawk (Buteo platypterus) . She issued a continuous series of calls for 20 minutes and flew seven circle flights. At 21:25 she flew to the nest tree, perched on top of it, and peered down at the nestlings. She then dropped gently to the artificial nest and exchanged a series of soft calls with the young. A thunder storm occurred the night of 28 June. On 29 June both young were present with bulging crops, fresh bullheads (Ictalurus spp.) and ciscos (Coregonus sp.) were in the nest, and both parents flew circle flights around the nest for the entire period that the senior author was present at the nest. Activity at the nest was observed on 29 and 30 June and parents brought food regularly. To our knowledge this is the first time that an experiment such as this has been recorded in the literature for this species. Both birds successfully fledged from the nest and were seen flying in the vicinity of the nest during the month of October. This work was funded by grants to the senior author for Bald Eagle research from the Society of the Sigma Xi Grants-in-Aid of Research, and from the National Audubon Society. — Thomas C. Dunstan, Department of Biology, University of South Dakota, Vermillion, South Dakota (Present address: Department of Biological Sciences, Western Illinois University, Macomb, Illinois 61455) and Melvin Borth, RR 1, Coleraine, Minne- sota 55722, 8 July 1969. Territorial conflict in the American Woodcock. — I reported in-flight, physical contact between two male American Woodcocks ( Philohela minor) (in Sheldon, The liook of the American Woodcock: 52, 1967). I believe that this was the first report of in-flight contact in this species although “tilting” has been reported in the European Woodcock (Scolopax rusticola) (Slater, British birds with their nests and eggs, V:106, 1898). This note presents additional details of the observation. On 30 April 1961 I observed the courtship activities of two woodcock which had established singing grounds within 300 feet of each other in ahandonetl fields in Leverett, Franklin County, Massachusetts. The two males were displaying in an ir- regular sequence and the flights freijnently overlapped in time. At 19:30 bird “B”, whose ascending flight spirals had been gradually shifting on successive flights, flew directly over the spot where bird “A” had just plummeted to the ground. “A” flew without a pause after landing and ascended silently and nearly vertically (instead of in its normal gradual southerly flight route) to intercept the “B” bird. Physical 328 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 contact took place at an estimated height of 75 feet. The birds ascended perhaps another 25 to 50 feet while fluttering breast to breast. They then locked together and fell 50 to 75 feet before breaking apart. One bird flew off in straight level flight in a north-northwesterly direction, closely pursued by the other bird until they were lost in the deepening dusk. The entire encounter lasted only thirty seconds. Civil twilight ended at about 19:33; this coupled with a clear sky and rise of a full moon at 18:46 provided a good background against which the performing birds were clearly silhouetted. After about five minutes a bird, that I believe to have been one of the original two birds, returned from the exact direction of departure and “peented” from the singing ground of bird “A.” After its next flight it “peented” from the singing ground of the “B” bird. It continued to use these two grounds alternately. This alternate use, by a single bird, of both singing grounds continued for the next two evenings. For the remainder of the season only the singing ground of the “A” bird was utilized while that of the “B” bird remained untenanted. All elements of the performance except the in-flight contact have been described by others, although not in the complete sequence that I observed (Pettingill, The American Woodcock, Philohela minor (Gmelin) : 287-291, 304, 1936; Pitelka, Wilson Bull., 55:100, 105, 107-109, 113, 1943; Sheldon, op. cit. : 44, 62) . I use the term dual flight to describe the synchronized or responsive flight of two woodcock in close proximity in contrast to the normal courtship flight of the male when performed by two birds simultaneously (Bent, U. S. Natl. Mus. Bull., 142:64, 1927) and the flight described by Forhush (Birds of Massachusetts and other New England States, 1:388, 1925) which probably involved a female. Dual flight has been reported in the American Woodcock by Brooks (Auk, 52:307, 1935) the Speirs (Pitelka, op. cit.: 105) and perhaps best described by Bagg and Eliot (Birds of the Connecticut Valley in Massachusetts, 208, 1937). Pitelka (loc. cit.) has suggested that “double” flight is due to the accidental simultaneous initiation of song flight by two males. Dual flight in the European Woodcock has been reported by Bannerman (The birds of the British Isles, 9:110, 1961) ; Warwick and van Someren (Scottish Naturalist, 222:170, 1936) who believe dual flights to be those of male and female although as Pitelka (loc. cit.) notes there seems to he no clear evidence on the sex of participating birds and Slater (loc. cit.) who reports that “tilting” of two, or even three, birds together has been ascribed to pairing activities but Slater considers it playfulness since he observed “tilting” up to the end of May. However, Sheldon (op. cit., 164) says the European Woodcock has two peaks of singing activity one in April and early May and one in .Inly. More work needs to be done on the problem of territoriality in the woodcock, hut I believe that dual flight, at least in the American Woodcock, occurs too infrequently to consider it a normal part of pairing activity and too frequently to consider it as the coincidental initiation of song-flight by two males. Furthermore, dual flight differs from normal song-flight and in my observation coincidental flight is ruled out. I suggest that in the American Woodcock dual flight represents a high intensity aggressive con- frontation between two territorial male woodcock that may be followed on rare oc- casions by actual in-flight combat. I thank Dr. Stephen M. Adler of Mount Holyoke College for calculation of the time of sunset and moonrise at Leverett, Massachusetts. — Frederic W. Davis, Fitchburg State College, Fitchburg, Massachusetts, 20 June 1969. September 1970 Vol. 82, No. 3 GENERAL NOTES 329 Chuck-Will’s-Widow in Connecticut. — On 26 June 1969 I found a Chuck-Will’s- Widow {Caprimulgus carolinensis) dead on a road near Stoney Creek, New Haven County, Connecticut. This is the second specimen record of tins species for Connecticut. The first specimen was found in New Haven, 10 miles west of Stoney Creek, on 17 May 1889 (Sage and Bishop, The birds of Connecticut, Connecticut Geol. and Nat. Hist. Survey. Hartford 1913). The bird is now in the Peabody Museum of Natural History, Yale University (No. 85435). The bird was an adult female with the ovary slightly enlarged (five ova measured 2 mm in diameter) and it had little fat. It showed no body or tail molt but the first three primary flight feathers on each wing were new. The stomach was filled with 68 small white geometrid moths iEnnomos subsignarius) and six June beetles iPhyl- lophaga sp.). The stomach contents reflect the unusually high population peak of this geometrid moth that occurred in Connecticut during late June. — Eugene S. Morton, Department of Biology, Yale University, New Haven, Connecticut, (Present address: Smithsonian Tropical Research Institute, Box 2072, Balboa, Canal Zone), 12 August 1969. Predation of a Black Rat Snake on Yellow-shafted Flicker Nestlings. — At 18:45 on 10 June 1968, five miles north of Burlington, Des Moines County, Iowa, I observed the predation of a black rat snake (Elaphe obsoleta) on a nest of half-grown Yellow-shafted Flickers (Colaptes auratus) . Predation of rat snakes on birds is not unusual and predation on nestling woodpeckers has been previously mentioned ( Nolan, Wilson Bulk, 71:381-382, 1959; Noland, The Kentucky Warbler, 36:29-30, 1960; .Stickel, Auk, 79:118-119, 1962). Of particular interest in this case is the extraordinary climbing ability exhibited by this snake and the apparent passivity with which the adult bird let its nest be robbed. The nest tree, a dead American elm (Ulmus americana) approximately four feet in diameter at breast height, had no bark and was worn quite smooth by weather. There were no branches on the tree between the ground and the nest branch, though the trunk was much convoluted near the base. There were no evident holes other than the nest hole and the tree did not appear to be hollow. The nest was about 20 feet above the ground in a branch extending southeast from the trunk at a 45 degree angle. At the nest entrance the diameter of the limb was approximately 15 inches. The only apparent way for the snake to have reached the nest was by climbing the smooth, featureless surface of the tree. When first observed, the snake was in the nest with only the last eight inches of tail extending from the hole. A female flicker, presumably one of the parent birds, was perched quietly in a second dead elm 30 yards away in line of sight with the nest hole. This bird remained in its position for 45 minutes before it quietly left, never approaching the nest tree. About five minutes after I discovered the nest the snake’s head appeared in the hole with a young flicker in its mouth. The bird, being swallowed tail first, was about half the size of an adult, had contour feathers just emerging from their sheaths, and appeared to have just opened its eyes. The nestling was lifeless. At first staying tight against the surface of the limb, the snake slowly began weaving back and forth and slightly up and down from one side of the limb to the other. Two large swollen areas evidenced previous victims, presumably other flicker nestlings. The weaving and contortions about the nest hole appeared to be aiding in the swallowing of the third victim, though 20 minutes later the head and one wing still protruded from the snake’s mouth. At this 330 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 point the snake withdrew into the hole (19:15) and did not emerge while it was still light enough to observe. Black rat snakes are noted for their climbing ability (Johnston and Gaunt, Kansas Ornithol. Soc. Bull., 12:22-23, 1961; Fitch, Copeia, 1963:649-658, 1963) and Surface (Bull. Div. Zook, Pennsylvania State Dept. Agr., 4:113-208, 1906) found 30 per cent and Fitch (op. cit.) found 23 per cent of black rat snake food consists of birds or their eggs. Though normally adult birds would be difficult prey for a snake, an incubating or brooding adult, as well as nestlings and eggs, would he easier prey. A hole-nesting bird such as a woodpecker, while having a safer nest in many respects and an- easier nest to defend, has no avenue for escape if surprised by an arboreal snake. Birds are not totally helpless in the face of such an adversary, and, may at times be successful in re- pelling the predator. Boone (1960. Masters Thesis, University of Kansas, Lawrence, Kansas) observed a male Red-bellied Woodpecker iCenturus carolinus) defending its nest against a black rat snake. Nolan (op. cit.) and Noland (op. cit.) describe possibly fatal attacks on arboreal snakes by nesting Pileated Woodpeckers {Dryocopus pileatus) . Fitch (op. cit.) mentions that Blue Jays (Cyanocitta cristata) have also been seen attacking black rat snakes. A second defense against arboreal snakes, or at least a distraction for the snake is a mobbing reaction by birds. Once a snake has been observed by a bird, cries of alarm generally attract other birds. Fitch (op. cit.) reported such aggregations involving several species. In the case of the Yellow-shafted Flicker, there was no evidence of nest defense or mobbing, but either or both may have occurred before tbe snake reached the hole. Though the snake was completely hidden within the nest hole from 19:15 to dusk, knowledge of the snake’s presence or fright from an earlier encounter with the snake apparently kept the flicker from returning to the nest to feed or brood its young. — Jerome A. Jackson, Museum of Natural History, University of Kansas, Lawrence, Kansas a May 1969. (Present address: Dept, of Zoology, Mississippi State University, State College, Mississippi 39762.) Wing flashing in a Brown Thrasher and Cathird. — Wing flashing has been fre- quently reported for Mockingbirds {Mimus polyglottos) and occasionally for other Mimidae (Whitaker, Wilson Bull., 69:361, 1957; Batts, Auk, 79:112, 1962; Horwich, Wilson Bull., 77:264, 1965: Ricklefs, Wilson Bull., 78:47, 1966). Horwich stated that this behavior is a response to a strange situation or potential predator. This has been supported by Hicks (Auk, 72:296, 1955) who oljserved wing-flashing by a Mockingbird in response to a blacksnake (Coluber constrictor) and by Selander and Hunter (Wilson Bulk, 72:341, 1960) in response to a Screech Owl iOtiis asio) . On 29 June 1969 a Brown Thrasher (Toxostoma rufum) was first seen as it scolded a 32-inch long buttermilk snake (Coluber constrictor anthicus) in Nacogdoches County, Texas. Within 3 minutes six Blue Jays ( Cyanocitta cristata) , three Cardinals ( Richmondena cardinalis) , two Catbirds ( Dumetella carolinensis) , and two Carolina Wrens (Thryothorus ludovicianus) joined the Brown Tlirasher. The Brown Thrasher extended its wings outward and slightly upward at the rate of once every 14 seconds. The extension was accomplished with a slight hitch when the wings were two-thirds extended. The tail was spread and held straight out behind. The two Catbirds both spread their tail and extended their wings while hopping around excitedly near the Brown Thrasher. Both Catbirds extended their wings in a September 1970 Vol. 82, No. 3 GENERAL NOTES 331 single motion but held them out 4^5 seconds as compared to the Brown Thrasher which kept its extended only 1-2 seconds. None of the other birds present extended their wings. After 20 minutes the snake crawled out of sight in some dense bushes and all the birds left the immediate area. — Edwin D. Michael, Biology Department, Stephen F. Austin State University, Nacogdoches, Texas 75961 (Present address: Division of Forestry, if est Virginia University, Morgantown, West Virginia 26506). 28 July 1969. Re-evaluation of two supposed hybrid birds. — In 1967 Keith L. Dixon requested information on a reported hybrid chickadee supposed to be in the U. S. National Museum. The specimen could not be found at that time but it was recently discovered in the course of routine expansion and rearrangement of the Paridae in the USNM collection. When I informed Dr. Dixon that in my opinion the bird was not a hybrid he urged preparation of a note indicating the apparent basis of the record. It seems ap- propriate to include comments on a White-crowned Sparrow specimen also misidentified as a hybrid, a situation of which I have been aware for some years. Parus atricapillus X P- gambeli. — This hybrid combination was reported by Suchetet (1897) on the basis of a specimen in the U. S. National Museum about which Robert Ridgway had written him. Ridgway is quoted as saying that the bird was in every respect exactly intermediate between the two forms. No other information about the specimen is given. Tlie record is repeated by Cockrum (1952) and Gray (1958) without comment. Specimen No. 60433 in the U. S. National Museum almost certainly is the bird about which Ridgway wrote. The locality on the label is “Bitter Cottonwood;” the museum catalog expands this to Bitter Cottonwood Creek, Wyoming Territory. The bird, which is not sexed, was collected by H. D. Schmidt on 14 August 1870 and was originally identified as Parus atricapillus. The notation “& P. montanus (Hybridl)’' was later added to the label by Ridgway; the name montanus as used in that instance refers to the present Parus gambeli. The specimen is in fairly good condition, hut the head is somewhat flattened. Contrary to the remark attributed to Ridgway, this specimen appears to be typical of P. atricapillus in every respect of size, proportion, bill shape, and color, except that it possesses traces of white superciliary stripes. The feathers that make up these stripes are merely edged with white rather than fully white tipped as in P. gambeli, and the stripes do not join across the forehead as they do in that species. A relatively small number of feathers is involved in the stripes, which do not extend as far posteriorly as in typical gambeli. I believe that this bird is best considered an aberrant example of Parus atricapillus rather than a hybrid between that species and P. gambeli. Wetmore (1931) mentions examining “a number” of Black-capped and Carolina Chickadees iP. carolinensis) with one or more white feathers at the junction of the auricular and crown patches, where the stripe on P. gambeli occurs. Zonotrichia leucophrys X Z. albicollis. — This hybrid combination was twice reported by Abbott (1958, 1959) on the basis of a single male bird taken at Fort Belvoir, Virginia, on 5 January 1958. The specimen is No. 468554 in the USNM. James K. Lowther and I examined this specimen on separate, occasions in 1962 and we independently concluded that it is an example of Z. 1. garnbelii and not a hybrid. The “very large and broad loral area” cited by Abbott ( 1959) as a criterion for tbe hyluid determination results in large part from the make of the skin. 332 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 The bend of the wing is not ‘'lemon yellow” as stated by Abbott (op. cit.) nor is it the same as the color of of the bend of the wing in alhicollis. The bend of the wing on the bird in question is faintly tinged with yellow and but slightly more yellowish than normal for Z. 1. gamhelii, well within the range of color shown in the species. The other features of the bird cited by Abbott are within the range of variation of the white-crown. A whitish throat patch, present in the bird under consideration and the feature at first most suggestive of hybridization although not specifically mentioned by Abbott, is a not uncommon attribute of the White-crowned Sparrow; in the bird under consideration, it is merely more extensive than usual. There is no evidence of the black malar stripes which often serve to set off the throat patch in the White-throated Sparrow. Sibley (1956) reported a Golden-crowned Sparrow (Z. atricapiUa) with a white throat, an occurrence strikingly similar to the one under discussion. He also mentioned two others of that species with some white in the throat and a Z. /. gambelii with a very- pale throat. Sibley wrote: “These facts suggest that there is a normal genetic basis for white in the throat plumage of atricapiUa. It seems probable that the white throat in this otherwise normal specimen of atricapiUa is due, not to hybridization, but either to the chance coalition of a larger than usual number of multiple factors affecting white throat plumage or to a mutation which affected the deposition of pigment in the feathers of this area.” With the substitution of the name leucophrys for atricapiUa, that state- ment aptly fits the present situation. I am grateful to Keith L. Dixon, Roxie C. Laybourne, and Susan Covington for com- ments and assistance in the preparation of this manuscript. Literature Cited Abbott, J. M. 1958. Hybrid White-crowned X White-throated Sparrow. Atlantic Naturalist, 13:258-259. Abbott, J. M. 1959. A hybrid White-crowned X White-throated Sparrow. Wilson Bull., 71:282-283. CocKRUM, E. L. 1952. A check-list and bibliography of hybrid birds in North America north of Mexico. Wilson Bull., 64:140-159. Gray, A. P. 1958. Bird hybrids. Commonwealth Agricultural Bureaux, Farnham Royal, Bucks, England. Sibley, C. G. 1956. A white-throated Golden-crowned Sparrow. Condor, 58:294-295. SuciiETET, A. 1897. Des hyhrides a I’etat sauvage. Regne animal. Classe des Oiseaux. Paris. Wetmore, a. 1931. Warm blooded vertebrates. Part 1, Birds. Smithsonian Sci. Ser., 9. Richard C. Banks, Bureau of Sport Fisheries and Wildlife-, U. S. National Museum, Washington, U. C. 20560, 14 August 1969. The avifauna of the Sand Draw local fauna (Aftonian) of Brown County, Ne- braska.— The first birds known from the Sand Draw local fauna were reported by Jehl (Auk, 83:669-670, 1966). The fauna is considered to be Aftonian (first interglacial) in age (see McGrew, Field Mus. Nat. Hist., Geol. Ser., 9:34-35, 1944, and Hibbard. Michi- gan Acad. Sci., Arts, and Letters, 62nd Ann. Rept., p. 19, 1960), and as Jehl (op. cit.) pointed out, “None of the avian fossils contradict this interpretation, and the presence of a large stork seems to support the view that this fauna lived in a warm, interglacial pe- riod.” The fossils reported herein were collected by C. W. Hibliard of The University of .Sc(itcmber 1970 Vol. 82, No. 3 GENERAL NOTES 333 Michigan Museum of Paleontology and his field party during the summer of 1968. The birds are as follows: Anas discors Blue-winged Teal. — Three hones, a complete but damaged left humerus (UMMP No. V57157 from SW 1/4, NW 1/4 Sec. 25, T31N, R22W, Brown County, Nehr.f, the distal end of a right humerus (UMMP No. V57020, from SE 14, SE 14, SE 14, Sec. 1, T31N, R23W, Brown County, Nebr.), and a complete right coracoid (UMMP No. V57158, from the same locality as V57157) represent this species. In total length the humerus measures 62.3 mm, the coracoid, 33.7 mm. Lateralhis sp. Small rail. — The distal end of a right coracoid (UMMP No. V57019, from W 14, NW 14, Sec. 25, T31N, R22W, Brown County, Nehr.) represents a small rail similar to the living Lateralhis rails hut is too fragmentary to permit positive identifica- tion to species. Speotyto cunicularia intermedia, new subspecies. Sand Draw Burrowing Owl. Type. — Fig. 1. Proximal 33 mm of left tarsometatarsus (UMMP No. V57018, from NW T4, NW 14, Sec. 26, T31N, R22W, Brown County, Nehr.). Collected by C. W. Hibbard and field party, summer, 1967. Fig. 1. The distal ends of the tarsometatarsi of, from left to right, the type of Speotyto cunicularia inegalopeza, S. c. intermedia, and Recent Speotyto cunicularia hypugaea (UMMZ No. 99406). i I Diagnosis and Comparisons. — This tarsometatarsus represents an owl belonging to the ' genus Speotyto, similar to the Recent 5. cunicularia in all characters except size of troch- leae and shaft which are more robust in the fossil. Ford (Condor, 68:472-475, 1966) de- scribed 5. megalopeza from the Rexroad formation of the Upper Pliocene of Kansas as, “Morphologically similar to S. cunicularia hut distinct in having slightly more robust troch- leae and a much wider and thicker shaft.” The Sand Draw fossil is a perfect intermediate 334 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 between the Recent 5. cunicularia and the Pliocene S. megalopeza in robustness, and in my opinion S. megalopeza and the Sand Draw Burrowing Owl represent a temporal dine leading to the Recent S. cunicularia. I therefore recommend making S. megalopeza a temporal subspecies of the Recent S. cunicularia to best reflect its relationships. Measurements. — The Sand Draw fossil measures in width across trochleae, 7.6 mm: width of shaft, 3.3 mm, measured 9 mm from distal surface of groove of middle trochlea; and depth of shaft at same level, 2.2 mm. Corresponding measurements for the type of S. megalopeza are, respectively: 7.6 mm, 4.0 mm, and 2.3 mm. The measurements that Ford top. cit.) gives, “. . . for the largest (UMMZ No. 99406) of 13 individuals of cunicularia examined are, respectively, 7.6 mm, 3.2 mm, and 1.9 mm.” Speotyto cunicularia megalopeza also is known from the Fox Canyon local fauna of the Rexroad formation, Upper Pliocene of Kansas (Ford, op. cit.), and from the Hagerman local fauna of the Glenns Ferry formation. Upper Pliocene of Idalio (Ford and Murray, Auk, 84:115-117, 1967). The modern form, S. cunicularia, has been reported from the McKittrick and Rancho La Brea deposits of the late Pleistocene of California (Wetmore, Smith. Misc. Coll., 131(5) :87, 1956). Passerines. — Several fragmentary bones represent small passerines but are unidentifi- able to family. Egg shells are commonly recovered from the matrix. The presently known avifauna of the Sand Draw local fauna is as follows: Horned Grebe Stork Canada Goose Trumpeter Swan Blue-winged Teal Bufflehead Small Rail Burrowing Owl Small Passerines Podiceps auritus cf. Ciconia maltha Branta canadensis Cygnus buccinator^ Anas discors Bucephala albeola Laterallus sp. Speotyto cunicularia intermedia I wish to thank Drs. C. W. Hibbard, R. W. Storer, and H. B. Tordoff for their criticism of the manuscript, and Karoly Kutasi for taking the photograph for Figure 1. Financial support for Dr. Hibbard’s field work in Nebraska was provided by a grant from the Na- tional Science Foundation (GB-5450). My research was supported by a grant from the National Science Foundation, GB-6230, to N. G. Hairston, The University of Michigan, for research in Systematic and Evolutionary Biology. — J. Alan Eeduccia, The University of Michigan Museum of Zoology, Ann Arbor, Michigan. [Present address: Department of Biology, Southern Methodist University, Dallas, Texas), 5 April 1969. fragment of a tarsometatarsus (Frick prospecting loc. No. 263) from the Frick Collection of The American Museum of Natural History has been identified by Patricia V. Rich of the A.M.N.H. Dept, of Paleontology as close to the Recent C. buccinator. ORNITHOLOGICAL NEWS Inflation makes no exceptions for scientific societies,, and at the recent meeting of the Council it was reluctantly voted to raise the dues. For 1971 membership dues in the \!vilson Society will be $8 for Regular Members, $10 for non-member and institutional subscriptions, and $15 for Sustaining Members. The contribution for Life Membership will go up to $200, but anyone making the initial installment on a payment for Life Membership before 31 December 1970 can do so at the old rate. In return for this increase in dues it is our hope to make the Bulletin larger, and to reduce the long delay time in publication of papers. The inside front cover of each issue of the Bulletin carries information about the Josselyn Van Tyne Library, one of the unique features of The Wilson Society. Each member should, then, be aware of the opportunity that he has to borrow books from the Library, but the Library Committee reports that in the 1969-70 year only 32 people availed themselves of this privilege. Perhaps cover material does not get read, and perhaps this notice will remind our members of the existence of the Library, which is a remarkably complete collection of the ornithological literature, journals and books, both technical and popular. With new book prices what they are today it would seem that many members would be willing to pay the return postage to Ann Arbor for even the most casual reading. Some time ago an anonymous donor arranged for an award for non-professionals to be known as the Margaret Morse Nice Award. Regrettably, and surprisingly, there were no applications for this award in 1970. In the entire membership there must be at least one person who could use $100 to help out his ornithological studies, and who meets the requirement of not being affiliated with a college or university. We have received notice of the death of two longtime members: Life member Dr. Mary Juhn of Beltsville, Maryland on 3 May 1970 and James L. Baillie of Toronto, Ontario on 29 May 1970. The Society has been the beneficiary of a gift for the purpose of awarding a monetary prize of $150 for the best paper and $50 for the second best paper appearing in The Wilson Bulletin during one calendar year. A committee of three, one of whom will be the Editor, will be appointed to judge the papers. In June 1970, the Siam Society issued a memorial number of its Natural History Bulletin in honor of the late Herbert G. Deignan, an authority on the Birds of Southeast Asia, especially Thailand. He was Secretary of the American Ornithologist Union from 1959 to 1961. The 200-page issue includes papers by friends and colleagues of Deignan’s, covering subjects in which he was interested. Copies may be obtained for $2.50 plus 500 Seamail postage from the Siam Society, 131 Lane 21, (Asoke) Sukhumvit Road, P. O. Box 65, Central, Bangkok, Thailand. 335 ORNITHOLOGICAL LITERATURE A Comparative Study of the Behavior of Red-winged, Tricolored, and Yellow- headed Blackbirds. By Gordon H. Orians and Gene M. Christman. University of California Publications in Zoology, Vol. 84, 1968: 81 pp., 2 pis., 30 figs., 10 tables. $3.00. The purpose of this study is to “analyze the influence of the striking differences in social organization upon the evolution of behavior” in three marsh-nesting icterids. Displays (other than vocalizations) of all three species are described in 19 pages, nine of which are comprised of excellent sketches by the junior author. Vocalizations are described in 25 pages in which appear 16 figures of sonographs. Comparison of all displays and vocalizations is achieved by a system of scoring “based upon the con- spicuousness of the displaying bird.” Points are added according to the degree of erection of plumage of diffei'ent parts of the body, spreading of wings and tail, etc., and this information is presented in tabular form. This is an interesting way of giving emphasis to the importance of the display components and their possible combinations. Displays and vocalizations of all three species are related to specific stages of the breeding cycle in six figures. Displays and vocalizations are considered to function primarily to communicate information. Based on a set of assumptions, namely, that information of environmental, social, identifying, and locating nature is being communicated, an analysis is made, but for the male Red-winged Blackbird only, of the amount of information transferred by each display and vocalization. An “evolutionary analysis of blackbird behavior” is based on the “importance of five major factors on the evolution of similarities and differences both within species (especially sexual differences) and between species.” These factors are: species recogni- tion, social organization, habitat, plumage patterns, and motivational changes. This interesting discussion covers 13 pages. In a concluding section the authors speculate briefly on the origins of blackbird displays. Landing movements, it is suggested, may have given rise to aspects of flight disjilays and displays accompanying basic song; vocalizations “probably all have been ulti- mately derived from breathing movements. . . .” Caution is advised ( p. 75) in interpreting behavior in relation to causation : “Behaviorists attempting motivational interpretations are subject to errors comparable to those of a paleontologist uncritically assuming that a group of organisms necessarily evolved where most living members occur.” A fore- warning of this point of view is given in the introduction, the authors noting that they have largely omitted motivational analysis in the belief that descriptive field studies can yield only “crude speculation” in this respect. Evidently, something more than “single frame analysis of over 2,000 feet of motion pictures,” a large series of recordings of vocalizations, and field observations during eight breeding seasons is necessary in order to obtain data that will yield information on motivation. Perhaps the authors are simply more candid than most of us, their uncertainties in this behavioral study being freely admitted: “Some behaviors. . .are exceedingly difficult to understand” (p. 54) ; “. . .it is exceedingly difficult to measure information transfer between individuals. . .” ( p. 57) ; “. . .the risks and the benefits of social behavior patterns are exceedingly difficult to measure. . .” (p. 62); “. . .since many of the displays are associated with a wide variety of vocalizations we have found it exceedingly difficult to 336 Seplciiibcr 1970 Vol. 82, No. 3 ORNITHOLOGICAL LITERATURE 337 fit them into such a scheme. . (p. 74) ; . .song and other territorial vocalizations. . . and their associated displays should evolve primarily internal control and should he exceedingly difficult to analyze. . .” ( p. 75). (Italics mine). This work was evidently carefully proof-read for there are few typographical errors. Some of the graphs, e.g., Figs. 16, 19 and 24, are poorly set, and the illustrations of Wing h lipping (Fig. 4) have reversed captions. Figure 4d illustrates Wing Flipping in the female Redwing (as drawn from a photo in Nero, 1956:14). The section on displays was of particular interest to me since, as the authors state, frequent references were made to reports by me on behavior of two of the species con- cerned, the Redwing and the Yellowhead (Wilson Bull., 68:5-37, 129-150, 1956; Wilson Bull., 75:376-413, 1%3). In view of the significance which the authors attach to the number of displays in each species and especially the number and kinds of components in what are called equivalent, comparable, or analogous displays, it is important to establish that such displays are comparable and disparate. Some questions may be raised in this respect. The male Yellowhead is said (p. 7) to have a flight display that is similar to the “Flight- song” of the male Redwing, though it differs in that it is always silent. It also differs from the Redwing in that it is given only over the territory though in the latter it is also given upon leaving and returning to the territory. Further, it is said to differ in that it often leads to an elevated wings display upon landing from which often a nest- site demonstration follows. This display, though differing from the “Flight-song” of the Redwing in three major respects, is treated as a corresponding display (Tables 2 and 3, pp. 50-53) . A second “territorial flight display” in the Redwing (p. 7) is called “Fluttering Flight. . . . After landing the male commonly continues the display while perched as the Defensive Flutter. . . .” The latter ( p. 16), considered a “perched analog” of the former, “is most common during the early stages of territory establishment and when the females are arriving.” This display appears identical to behavior that some observers have re- garded as indicative of sexual excitement. And note that the “Si-sf-si” call accompanying Defensive Flutter (p. 45-46) “may not be really distinct from the Ti-ti-ti [precopulatory] call” (p. 46). No reason is given for the reference to defensive behavior, a seemingly inappropriate term especially in a paper which attempts to avoid motivational aspects. In any case, the appearance of a display (“Flutter”) both when perched and when in flight would not seem to warrant description and use as two separate displays. Under “Precopulatory Display” of the male Redwing (p. 20) it is said that “In the full intensity display the male walks or jumps around as much as terrain and vegetation permit as he approaches the female. . . .” This is incorrect, the statement unfortunately implying some similarity to precopulatory display of the male Yellowhead. The male Redwing walks or runs toward the female and “jumps around” only as necessary to surmount obstacles in his path, thus on a level surface there is no jumping. Although a “postcopulatory display” was described and illustrated for tbe Tricolor (p. 20) and was used as a basis for comparative study, the authors note that there was “insufficient evidence to determine whether this is a regular display which is widely used in this context. . . .” “Postcopulatory display” in the male Yellowhead (illustration based on a photo supplied by me) in which the male raises its tail is said (p. 20) to be of “regular” occurrence. This is misleading. Although tail raising occurs regularly in this species in agonistic situations it does not regularly follow copulation. Tlie state- ment that “tail raising has not been noted. . .under any circumstances in the Redwing 338 THE WILSON BULLETIN Sei)ten)hcr 1970 Vol. 82. No. 3 (except rarely in the Crouch). . is also misleading for it is of common occurrence in feeding groups (see Nero, 1956: 13; 1963: 394). No mention is made of the extensive though perhaps inconclusive discussion of tail raising as an appeasement display (in Nero, 1%3: 391-394), the authors concludin g only ( p. 20) that “its function is still obscure.” Considering that this study concentrates on relationships between plumage and com- munication the statement (p. 5) that the male Yellowhead “apparently has no plumage modifications other than the development of a yellow head and white areas on the wing” is surprising. The yellow cloacal patch (referred to elsewhere by the authors, pp. 20, 72) appears to function in display, and the black area surrounding the eye and the base of the hill may well be significant. I am credited by the authors as having shown that “Bright colors on the throat and breast are the most common plumage aberrations of the Redwing” (p. 71). This is incorrect. Various albinistic features are far more common. When melanic pigmentation is inhibited in the throat and breast feathers, underlying carotenoid pigments become visible. Redwings and Yellowheads are said (p. 73) to he “completely dominant to the females at all times”; but, as already pointed out, there are conditions under which male Yellowheads are repulsed by their mates (Nero, 1963: 404). The statement that “Nero (1963). . .interprets the Asymmetrical Song Spread as a low intensity form of the Symmetrical Song Spread” (p. 16) is an error on the part of the authors (see Nero, 1963: 377). A great deal of emphasis is given to “Bill-up Flight” of the Yellowhead ( pp. 9, 19, 49, 52, for example) which is here regarded as a unique feature of this species. Un- fortunately, no comment is made regarding the proposed relationship of “Bill-up Flight” as a homologue of “Bill-up” display (Nero, 1963: 382-386). On the contrary, “Bill-up” display is considered a counterpart of “Bill-down” posture (p. 49). It is even stated (p. 9) that Bill-up Flight may be given with the hill pointed down! In the Summary (p. 77) a further comparison is drawn between Bill-up Flight of the Yellowhead and territorial flight display in the Redwing and Tricolor, though these are not related displays. The statement that Yellowheads make “short Bill-up Flights during which the birds also present their backs to each other” ( p. 19) is hard to reconcile with males ap- proaching each other in territorial boundary disputes. Bill-up display in the Redwing female is said ( p. 19) to be given “only to other females,” though I have already reported it as being given “occasionally to first-year males, and rarely to adult males” (Nero, 1956: 12). The above are examples of material in this paper that I found erroneous, questionable, or misleading. Possibly an attempt to describe and compare the behavior of three species in 10 pages led to the oversimplification and generalization that in my opinion detract from the value of the section on displays. Moreover, and unfortunately, many of these same points are raised again in the concluding sections of the paper. Doubtless the main points of the paper regarding the influence of social organization upon the evolution of behavior of these three blackbird species, as suggested to me by Professor Orians in recent correspondence, are valid in spite of my contention that some portions were hastily assembled. Thus the paper attains its major objectives. — Robert W. Nero. Sepleniber 1970 \’ol. 82, No. 3 ORNITHOLOGICAL LITERATURE 339 A Bird-Bander’s Guide to Determination or Age and Sex or Selected Srecies. By MerriB Wood. College of Agriculture, The Pennsylvania State University, University Park. 1969: 8M> X H in-, spiral binding, leatherette .covers, 181 pji., 2 figs. .13.00. Bird-banders and other field researchers have long felt the need for a guide, sum- marizing in a single volume, much of what is known about age and sex determination in living birds; Wood’s guide is intended as a step in this direction. As the title denotes, however, the hook is limited to selected species (I count 160), and coverage is restricted to the northeastern United States. Included are most of the commonly banded Pas- seriformes (House Sparrow, Blue Grosbeak and House Finch are missing) ; woodpeckers, a few hawks, small owls, etc. No herons, waterfowl, shorehirds ( excepting American Woodcock), gallinaceous birds, gulls, or terns are treated. Also missing are several western and northern species that occur fairly commonly within the northeastern U. S. (Western Meadowlark, Oregon Junco, Gray Jay, Boreal Chickadee, etc.) The author’s approach, based largely on the literature, is in the form of a key. A short introduction covers the “parts” (topography) of a bird. A crude diagram of a spread wing shows 10 secondaries and 10 primaries, with no mention of variation in these num- bers, although correct numbering of primaries is essential to the use of wing formulas cited later in the hook. Also in the introduction are discussions on the use of the incubation patch and cloacal protuberance in sex determination, and of the “skulling” technique. An index of species treated ( pp. 15-16) would he more convenient at the end of the hook. Each bird is listed under its common name, followed by the recommended hand size, A.O.U. number, and a statement regarding the reliability of the skulling method for that species. The main section of each key is based on whatever characteristics have lieen selected to aid in determination of age and sex, and the appropriate code for use I in preparing the Federal banding schedules is also indicated. A short summary of molt sequence, usually adapted from Forbush (Birds of Massachusetts and Other New England States, 1925-1929) or Roberts (Manual for the Identification of the Birds of Minnesota and Neighboring States, 1955), ends each account. As this work will undoubtedly become the standard guide for hundreds of eastern handers, it is unfortunate that a number of errors and confusions are included. For example, both sexes of the Blue-gray Gnatcatcher in first fall [basic] plumage lack the narrow black line bordering the front part of the crown, which is acquired by the male in a [prealternate I] molt in Feliruary. Adherence to Wood’s key, however, would classify any autumn gnatcatcher lacking the black forehead as a female; in actual practice only the adult male is identifiable after mid-August. In quoting Blake (Bird- Banding, 27:185, 19.56) on the relative length of the ninth primary of Connecticut and Mourning Warblers, an error is perpetuated that dates hack to Ridgway (U. S. Natl. Mus. Bulk, 50, part 2:622, 1902). The 9th primary of the Connecticut is longer (not shorter) than the 6th, and the 9th primary of the Mourning Warbler is usually shorter (not longer) than the 6th. For a full discussion, see Lanyon and Bull (Bird-Banding, 38: 187-194, 1967), a paper that should have been in Wood’s bibliography. The key for the American Redstart does not allow for males in second year plumage, and after the description of the fully adult male, a correction is needed to allow for birds in this plumage to he designated as ASY (after second year) from January through May; then AHY (after hatching year) only during the autumn months. Considerable confusion under the Scarlet Tanager is apparently based on a mis- understanding of the timing of the “prehreeding” [prealternate I molt as based on 340 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Forbush (ibid.); the age of a spring male cannot be correctly determined as the key is constructed. (From April through June the body plumage of all males is scarlet. Birds with gray-brown primaries and secondaries contrasting with black secondary coverts can be classified as second year birds; black primaries and secondary coverts indicate after second year.) The key to the Common Redpoll is also misleading, as it fails to allow for the huffy breasted immature male which does not acquire the pink breast feathers until after the first “postbreeding” [prebasic II] molt. Young males, then, key out as females! Also the bander should regard the key to the Cedar Waxwing as it relates to the red tips of the wing feathers as descriptive only of a general tendency. In the banding of over 3,000 waxwings in southwestern Pennsylvania, I have found many exceptions to this key: Birds of the year occasionally are found with very well de- \ eloped appendages; some older waxwings apparently never acquire them. The instances listed above represent only a sample of the errors of omission and com- mission within the main text. Of less importance are editorial errors such as the failure to list a reference to Baird (1964) in the “Literature Used” section at the end of the book; Amadon, 1966 reads “1965” on page 3, and the reference to Roberts (p. 17) should read 1955, not 1967. A more critical editing might have eliminated such minor errors as well as some of the others mentioned above. Tbe key provides an idea as to the reliability and time limits of tbe skulling technique for each species, which is the most original contribution of the book. Wood is wisely conservative in his treatment of the subject. As he notes (p. 13), “The skulling method probably can be used safely on many species at dates later than those given in this Guide.” The dates that are provided apparently reflect an approximate period after which it may be impossible to differentiate between adults and young because of completed pneumatization in some of the immature birds; that use of the obviously unossified skull after this point is not impaired is unfortunately not explained. For over two dozen species, including Catbird, the orioles, all of the blackbirds, many northern finches, and the Song Sparrow, we are told: “Age by skulling unlikely.” Since space was not a problem (almost all of the keys occupy less than half of the full page allotted), it would have been extremely helpful had a word or two of ex- planation been given in each case. Do the skulls of these species not pneumatize the first year? Is the skin of the crown too thick? Too dark? Does the skull of the immature pneumatize too early? As it is we can only speculate on Wood’s reasoning. In my own experience (in skulling well over 20,000 birds) I find that in many species where the problem is simply seeing tbe skull because of a dark or thick skin, an ex- perienced bander can safely classify at least some individuals as hatching year birds with the aid of a good artificial light and proper magnification. There are several other species, listed by the author as safe to “age” by skulling, that my research has indicated (Leberman and Clencb, MS. in preparation) often do not ossify until the second year or even later, and it might be appropriate to indicate them in this review. Included are the Empidonax flycatchers (use wing bar color as a double check), the White-breasted Nuthatch (the skulls of some individuals may never fully pneumatize). Barn Swallow, Swainson’s Thrush, Red-eyed Vireo (use eye color as a double check). Northern and Louisiana Waterthrushcs, Yellow-breasted Chat, Scarlet Tanager, and Indigo Bunting. For most of these, however, the area of unossified skull is usually quite small by the second autumn, and birds showing extensively un- pneumatized skulls can be determined as hatching year with reasonable assurance. Wood warns against using too much water in winter for wetting feathers while September 1970 \ ol. 82, No. 3 ORNITHOLOGICAL LITERATURE 341 skulling, suggesting that the birds he held until dry. At Powdermill Nature Reserve we avoid this problem by wetting the feathers with alcohol, which evaporates in a few seconds. A surprising number of the keys provide tables for sex or species determination by use of wing or tail length. Nowhere in the guide, however, is the new bander warned that use of such measurements usually requires great caution and judgment. As anyone who has measured the wings of a large sample of birds in the field is aware, the potential of error and inconsistency in his own data, as well as the variability in the methods of others, is great. Positioning of the wing along the rule, the amount of pressure applied, and feather wear all combine to open such measurements to question. Tail measurements on a squirming chickadee are doubly difficult; data for separating such birds as the Carolina and Black-capped Chickadees should, I believe, probably be used only in combination with the slight plumage differences. The geographic variation within such plastic and migratory species as Robin, Slate-colored Junco, and Song Sparrow also adds to the possibility of error in determining sex by wing length; in the Slate-colored Junco, might a large female /. h. carolinensis not key out as a male J. h. hyemalis? Caution would seem to be the key to the use of this book, which, despite some inadequacies, will prove useful to the prudent bird-bander. Perhaps its greatest con- tribution is to point to the gaps in our knowledge and hopefully prompt others to publish their findings. For as Wood notes in his Preface fp. 3), “For any particular species, somewhere there is certain to be a bander who has more information than is presented here. It is hoped that this knowledge will soon become available to others.”- — Robert C. Leberman. From Laurel Hill to Siler’s Bog. The walking adventures of a naturalist. By John K. Terres. Alfred A. Knopf, 1969. 8V2 X 6^/4, xix + 227 pp., 1 map, 32 ill us. by Charles L. Ripper. $6.95. Obviously John Terres belongs to the modest but select company of naturalists whose chief attributes in the research of natural history consist of time unlimited, spent within one limited area over a long period of years. The results of this kind of research are often astonishing. Reading directly from nature, the keen observer is able to follow installment after installment of events, which he can finally put together to form a factual and significant account. The enchantment and exhilaration of the discoverer is forever the reward of his painstaking work. All this is contained in Terres’ book and for this reason it is not just a tale of ramliling roving explorations and haphazard walks in the woods. Ambition and definite aims dictated and directed the naturalist’s observations. Concentration counts. The night was often turned into the most intensive work period and the ingeniously devised method and approach brought out meaningful information. Within the light and poetic framework commenting on the four seasons, study after study disclose facts about rabbits, foxes, mice, flying squirrels, raccoons, birds. We learn how the Turkey Vulture iCathartes aura) is guided to its prey, about the Red- tailed Hawk’s (Buteo jamaicensis) courtship flights, the Barred Owl’s (Strix varia) occasional excursions into shallow creeks, catching fish, and the courtship feeding of the Bobwhite (Colinus virginianus) . Especially interesting and noteworthy are the rather frequent accounts dealing with predation. The natural ending of a wild life is seldom witnessed, but the patient and 342 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 consistent watcher can sometimes follow the concluding episode or piece it together from signs written in the snow and on the ground. A Red-tailed Hawk attempts to strike a Turkey i Meleagris ga/lopavo) with a hrood of young, but the ten-pound hen rises into the air and forces the three-pound hawk to turn tail. A rabbit cheats a pack of dogs of their prey, while death in the jaws of a weasel catches up with another. In the last three chapters the author is at his best, not because the style of writing is outstanding, hut because the naturalist is in his glory and his involvement is so com- plete that it is impossible for the reader not to he carried away with him. A book full of so many attractively presented facts belongs in any nature library worthy of the name. Ripper’s sensitive and accurate drawings are a fine asset. — Louise de Kiriline Lawrence. Owl. By William Seiwice. Alfred A. Knopf, New York, 1969: 5 x 8 in., 93 pp., illus. with drawings by Walter Richards. $4.00. This might he called “just one more story of a pet owl’’ — but it is better than most. At least it was more appealing to this critic, perhaps because tlie author recognizes anthropomorphism for what it is and is rarely guilty of it, perhaps because of a rather unique style of presentation of his story. Mr. Service speculates on many aspects of Owl’s behavior. He performs simple experiments with this bird, described what the bird did, and rarely fell into the trap of attempted interpretation of this behavior. Whether you like owls or not, you will like this appealing little creature. There is one serious omission. At no time does the author bring out the point that in many states it is illegal to have a Screech Owl in captivity. I find myself shuddering over the number that may be taken into homes now, in misguided attempts to raise a pet like Mr. Service’s owl, without permit and without sufficient knowledge of how to do it. — Sally H. Spofford. ANNOUNCEMENT The North American Nest Record Card Program, Laboratory of Ornithology, Cornell liniversity wishes to remind contributors that 1969 nest records are still welcome. In addition the Program desires to accumulate data on nests from the pre-mid-1940s ( pre- pesticide era) for comparison. The Program still lacks Regional Centers in Idaho, New Hampshire, New Jersey, and Wyoming. PROCEEDINGS OF THE FIFTY-FIRST ANNUAL MEETING Jeff Swinebroad, Secretary The Fifty-first Annual Meeting of the Wilson Ornithological Society was held jointly with the Cooper Ornithological Society 18-21 June, 1970, at Colorado State University, Fort Collins. Colorado. Sponsors were Colorado State University, the Colorado Field Ornithologists, the Denver Field Ornithologists, and the Fort Collins Bird Cluh. The meeting started on Thursday with a welcome hy Gustav A. Swanson, Colorado State University and responses by Robert T. Orr, President of the Cooper Ornithological Society and William W. H. Gunn, President of the Wilson Ornithological Society. Paper sessions were held Thursday, Friday, and Saturday. On Friday there was a special symposium. Avian Ecology in Grasslands, arranged hy John A. Wiens. Friday evening there was a joint informal banquet, a buffalo barbecue and rodeo at the Two- Bar-Seven Ranch. The Colorado Field Ornithologists held a dinner meeting on Saturday. An evening program on field trips was given Saturday evening by Clait Braun, Birds of Rocky Alountain National Park, and Ronald A. Ryder, Birds of Pawnee National Grasslands. Three field trips were conducted on Sunday, two all day trips to the aforementioned areas, and a third trip of a half day to local areas. The recipient of the Wilson Prize, for the best paper presented by a student or non- professional member of the Wilson Society, was announced at the second business meeting and was Ronald AI. Case whose paper was “Bioenergetics of a Covey of Bob- white Quail.” First Business Meeting The first business meeting, held Friday morning, was presided over hy President Gunn. The minutes of the previous meeting as included in the Proceedings of the Fiftieth Annual Aleeting in the Bulletin were approved as published. The President designated the following temporary committees: Nominating: Phillips B. Street, Chairman, Aaron Bagg, Olin Sewall Pettingill. Resolutions: Kenneth C. Parkes, Chairman, Roland C. Clement, W. John Richardson. Wilson Prize: Harvey I. Fisher, Chairman, Robert W. Storer, Stephen M. Russell. Auditing: C. Chandler Ross. The Secretary reported a brief summary of the meeting of the Executive Council of the .Society: 1. The Council received and approved reports of the Treasurer, the Trustee’s report, the reports of the Alemhership, Student Membership, Library, Research Com- mittees, and the Editor’s report and the Secretary’s report. 2. On recommendation of the Research Committee the Council voted to award the Fuertes Award of $200 to Thomas C. Dunstan, South Dakota University, for his post-fledgling ecology of Great Horned Owls as determined hy telemetry. 3. The Membership Committee (David F. l^armelee. Chairman) reported over 100 new members. The President appointed the First Vice President, Pershing B. Hofslund as Chairman of the Membership Committee for the coming year. 4. The Student Membership Committee canvassed a large number of professors at colleges and universities and received 143 nominations for student memherships. The Council commended Chairman Douglas James for his efforts. 5. Dr. George Hall was reelected unanimously as Editor of the Wilson Bulletin. 343 344 THE WILSON BULLETIN SejHenibcr 1970 Vol. 82, No. 3 6. The Council approved a new dues schedule, starting next year. The dues will be: Active — $8.00; Sustaining — $15.00; Life — $200.00; and Patron — .$500.00. There will he a period when Life Memberships will he available at the current level of $150.00. 7. The 1971 meeting will he held 22-25 April on Dauphin Island, Alabama, with the Mobile County Bird Club as host. The Treasurer summaiized his report which is included here in full for the record : Report of the Treasurer for 1969 GENEjtAL Fund Balance as shown by last report 31 December 1968 $ 9,429.79 KECEIPTS Dues Active Memberships $ 3,019.44 Sustaining Memberships 310.00 Subscriptions to The Wilson Bulletin 2,707.00 Sales of hack issues of The Wilson Bulletin 935.40 Interest and dividends on savings and investments 2,997.57 Royalties from microfilming back issues of The Wilson Bulletin 111.15 Total Receipts $10,080.56 DISBURSEMENTS The Wilson Bulletin ( Printing & Engraving) . . . $12,814.24 Less contributions from authors 650.25 and illustration fund 1,000.00 11,163.99 The Wilson Bulletin (Mailing & Maintenance of List) .... 1,722.88 Editor’s expense 235.14 Secretary’s expense 39.10 Treasurer’s expense 391.17 Foreign discount, hank charge, and transfer fees 10.21 Annual Meeting expense 338.70 Committee expense 19.95 Miscellaneous expense 2.00 International Council for Bird Protection (1969 dues) .... 25.00 Transfer to Research and Award Funds 240.00 Total Disbursements $14,188.14 Excess of Disbursements over Receipts for Year 1969 $(4,107.58) GENERAL FUND CASH ACCOUNTS Checking Account $ 1,836.99 Savings Account 3,485.22 Balance in National City Bank, Cleveland, Ohio, 31 December 1969 .... $ 5,322.21 JOSSELYN VAN TYNE MEMORIAL LIBRARY BOOK FUND Balance as shown by last report dated 31 December 1968 $ 156.75 RECEIPTS Sale of duplicates and gifts 4.50 Total Balance and Receipts 161.25 September 1970 Vol. 82, No. 3 FIFTY-FIRST ANNUAL MEETING 345 DISBURSEMENTS Purchase of Books 33.10 Balance in National City Bank, Cleveland, Ohio, 31 December 1969 .... $ 128.15 LOUIS AGASSIZ FUERTES RESEARCH FUND, MARGARET MORSE NICE FUND AND ANNUAL MEETING PAPER AWARD Balance as shown by last report dated 31 December 1968 . RECEIPTS Contributions Transfer from General Fund Total DISBURSEMENTS Award to Richard E. Johnson $ 200.00 Award to G. Frederick Shanholtzer 100.00 Award to Martha Whitson 100.00 Total Disbursements Balance in National City Bank, Cleveland, Ohio, 31 December 1969 . 26.50 236.50 240.00 503.00 400.00 103.00 PREPAID STUDENT DUES Balance as shown by last report dated 31 December 1968 $ 115.00 RECEIPTS 0.00 Total 115.00 DISBURSEMENTS 10.00 Balance in National City Bank, Cleveland, Ohio, 31 December 1969 .... $ 105.00 ENDOWMENT FUND Balance in Endowment Fund Savings Account as shown by last report dated 31 December 1968 $ 3,607.00 RECEIPTS Life Membership Payments 1,130.00 Patronship Payments 300.00 Stock Dividends and Exchanges (included below) $5,(X)0 U.S. Treas. 8% notes due 15 May 1971 received in exchange for $5,000 U.S. Treas. 4% bonds due 10 October 1969 . 135 shares Phillips Petroleum Co. received from 2 for 1 split 33 shares Massachusetts Investors Trust (as capital gains distribution) Total Receipts 1,430.00 DISBURSEMENTS 0.00 Balance in Endowment Fund Savings Account National City Bank, Cleveland, Ohio, 31 December 1969 $ 5,037.00 SECURITIES OWNED ( listed at closing prices, 31 December 1969) United States Government bonds and notes $ 9,503.12 Canadian Provincial Government bonds 3,650.00 Corporate bonds 3,400.00 346 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Convertible Corporate bonds Convertible preferred stocks Common stocks Investment trusts Total Securities Owned . lotal Endowment Fund 31 December 1969 3,750.00 21,629.50 14,489.38 8,080.08 . . . 64,502.08 . . . $69,539.08 Respectfully submitted, William A. Klamm, Treasurer Also for the record here are summaries of the Library Committee’s Report and the Editor’s Report: Library Committee (William A. Lunk, Chairman) — There was a considerable increase in the number of contributions and a slight increase in the number of loans and journals received. Four thousand one hundred reprints were a gift of Mrs. Van Tyne from the library of her late husband Josselyn Van Tyne. Editor’s Report (George A. Hall) — Volume 81 (1%9) consisted of 496 pages. Papers received today should appear in 15 months. Of major importance to the Bulletin and to the Society was the retirement of Sewall Pettingill from the post as Ornithological Literature Editor. The several editors whom he has served and the Society certainly owe him many thanks for his fine efforts over the years. The new review editor is Dr. Peter Stettenheim. SECOND BUSINESS MEETING President Gunn presided over the second business meeting Saturday afternoon. Dr. Kenneth Parkes read the following joint Cooper-Wilson Societies resolutions: WHEREAS the Cooper Ornithological Society and the Wilson Ornithological Society have assembled in their first joint, annual meeting at Fort Collins, Colorado, 18-21 June, 1970, and WHEREAS the members of the two societies have benefited greatly from the devoted efforts of the Committee on Arrangements chaired by Dr. Ronald A. Ryder, and WHEREAS the superior facilities and services provided by Colorado State University have contributed immeasurably to the success and enjoyable nature of this meeting, THEREFORE BE IT RESOLVED that the Cooper and Wilson Ornithological Societies extend their grateful appreciation to the sponsoring organizations: Colorado State University, The Colorado Field Ornithologists, The Denver Field Ornithologists, and The Fort Collins Bird Club. WHEREAS the Wilson and Cooper Ornithological Societies represent an important cross section of the scientific community concerned with the study and conservation of birds in North America, and WHEREAS the officers and members of the Wilson and Cooper Ornithological Societies share a great concern about the future biological productivity of Alaska, particularly in view of pending proposals for exploitation of Alaskan resources, THEREFORE BE IT RESOLVED that the two societies wish, first, to commend .Secretary of the Interior Walter J. Hickel for insisting on proper scientific and engi- neering assessment of the impact of such exploitation on the environment of Alaska, and. second, to urge that final decisions relating to Alaska be made on the basis of a national accounting rather than merely state, regional, or special interest group con- siderations, and September 1970 Vol. 82, No. 3 FIFTY-FIRST ANNUAL MEETING 347 BE IT FURTHER RESOLVED that copies of this resolution he sent to Secretary (;f the Interior Walter J. Hiekel and to the Governor, U.S. Senators, and Representatives of the State of Alaska. WHEREAS more species of endemic birds have become extinct in Hawaii during the past century than in the entire North American continent, and WHEREAS at least one-third of the extant Hawaiian birds are now classified as ‘dare and endangered,” and WHEREAS wetland areas are essential to the survival of Hawaii’s marsh and pond l)irds, THEREFORE BE IT RESOLVED that the Cooper and Wilson Ornithological Societies urge that all State and Federally owned marshlands in Hawaii he declared Wildlife Refuges for these birds, and that pertinent privately owned lands he acquired and put into public ownership by the Federal or State governments or by both, and BE IT FURTHER RESOLVED that copies of this resolution be sent to Secretary of the Interior Walter .1. Hickel and to the Governor, U.S. Senators, and Representatives of the State of Hawaii. WHEREAS the first joint meeting of the Cooper Ornithological Society and the Wilson Ornithological Society has been a notable success in providing an opportunity for intellectual and social exchange among the members of the societies, THEREFORE BE IT RESOLVED that the officers of the societies be encouraged to take advantage of every opportunity to stage additional joint meetings of this type at suitable intervals. Respectfully submitted, For the Cooper Ornithological Society: Tom J. Cade, Richard F. Johnston, John Davis, Chairman. For the Wilson Ornithological Society: W. John Richardson, Roland C. Clement, Kenneth C. Parkes, Chairman. The resolutions were approved for both Societies without a dissenting vote by members in attendance at the meeting. The proposed new members of the Wilson Society as posted were elected without dissenting vote and the Secretary was instructed to cast a unanimous ballot. The Auditing Committee’s report was approved without a dissenting vote. The report included the following statement: “I have examined the Receipts and Ex- penditure Records of the Wilson Ornithological Society for the period from May 1, 1968 to May 31, 1970. The Receipts Journal was added and the totals verified. Disburse- ments were verified by examination of checks and bank records. I find all totals in William A. Klamm’s records to be correct. And, the balance in the National City Bank of Cleveland Checking Account to be .^5,403. 05 as of May 31, 1970. Frank P. McConoughey, Accountant.” Tlie following Nominating Committee’s Report was read by Dr. George H. Lowery, Jr.: President, William W. H. Gunn; 1st Vice President, Pershing B. Hofslund; 2nd Vice President, Kenneth C. Parkes; .Secretary, Jeff Swinehroad; Treasurer, William A. Klamm; Elective Member of the Council, Elden W. Martin. The slate was elected and the .Secretary was directed to cast a unanimous ballot. PAPERS SESSIONS Robert B. Payne, University of Michigan. Local Song Dialects and Population Size in a Parasitic Bird. 348 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 George B. Reynard, Cornell University. Study Problems of some Caribbean Bird Songs. Vivian Telford Anderson, The Utah State University. The Development of Selected Vocali- zations in Hand-reared Black-capped Chickadees. Daniel E. Hatch, University of Nebraska. Grouping Responses of Wild Quail to Separation Calls of the Bobwhite, Scaled Quail, and their Hybrids. Raymond B. Goldstein, University of Nebraska. Tracheal Resonance and Vocal Acoustics of some New World Quail. David G. Ainley, Johns Hopkins University. Comfort Behavior of Adelie, African, and Humboldt Penguins. Sidney A. Gauthreaux, Jr., and Kenneth P. Able, University of Georgia. The Influence of Wind on the Flight Directions of Passerine Nocturnal Migrants. William E. Southern, Northern Illinois University. Influence of Disturbances in the Earth’s Magnetic Field on Orientation of Ring-billed Gulls. Robert D. Ohmart and Robert C. Lasiewski, University of California, Davis and Uni- versity of California, Los Angeles. Energetic Significance of Solar Absorption and Hypothermia in the Roadrunner. Helmut C. Mueller, University of North Carolina. The Stimuli Eliciting Sunbathing in Birds. Ronald M. Case, Kansas State University. Bioenergetics of a Covey of Bobwhite Quail. Elden W. Martin, Bowling Green University. Correlation of Dietary Protein with Energy and Nitrogen Balance, and Temperature Tolerance in Tree Sparrows. Vaughn A. Langman, University of the Pacific. The development of Radio-biotelemetry Devices for Small Passerine Birds. Cynthia Carey, Occidental College. Comparison of Salt and Water Regulation in California Quail and Gambel’s Quail. Charles H. Trost, Idaho State University. Cardiovascular Adaptations of Horned Larks to High Altitude. Marsha Landolt and Robert B. Payne, University of Oklahoma. Thyroid Histology in the Annual Cycle, Breeding, and Molt in Tricolored Blackbirds. Larry C. Holcomb, Creighton University. Endogenous Factors affecting Incubation Behavior in Red-winged Blackbirds. Nancy S. Mueller, North Carolina State University. Sexual Dichromatism in the House Sparrow. Charles G. Sibley, Yale University. Avian Hybridization across the Great Plains. Kendall W. Corbin, Yale University. Serum Esterase and Lactic Dehydrogenase Poly- morphhm in the Metallic Starling. Andrew Eerguson, Yale University. Serum Albumin Polymorphism in Paradisaea minor, Paradisaea raggianna and their hybrids. Walter J. Bock and John Morony, Columbia University. Relationships of the Olive W arbler, Peucedramus taeniatus. Jerome D. Robins and Gary D. Schnell, University of Kansas and 0. and S. Ecosystems IRP-IRP. Skeletal Analysis oj the Ammodramus-Ammospiza Grassland Sparroiv Complex: A Numerical Taxonomy Study. Lowell Spring, Oregon College of Education. A Functional-anatomical Comparison of The Two Murres. George A. Clark, Jr., University of Connecticut. Bilateral Asymmetry and Individuality of Integumental Patterns on Avian Feet. Robert J. Raikow, University of California, Berkeley. The Morphology and Phylogenetic Significance of the Pelvic Girdle in Ratites. September 1970 Vol. 82, No. 3 FIFTY-FIRST ANNUAL MEETING 349 John Davis, Hastings Reservation, University of California. Breeding Schedule oj the Rufous-collared Sparrow in Coastal Bern. Russel P. Baida and Gary C. Bateman, Northern Arizona University. Colonial Nesting of the Pi non Jay. Lester L. Short, American Museum of Natural History. Habits of the Red-fronted Wood- pecker, Melanerpes cruentatus. C. John Ralph and Carol A. Pearson, Point Reyes Bird Observatory. Correlations of Age, Size of Territory, Plumage, and Success in Breeding White-crowned Sparrows. Erwin E. Klaas, Rockhurst College. Influence of Cowbird Parasitism on Nesting Success in the Eastern Phoebe. Daniel S. McGeen, Oakland University. Cowbird Density and Cowbird-host Interactions. Boh Stewart, Point Reyes Bird Observatory. Behavior of Wilsons Warbler. David B. Peakall, Cornell University. Breeding Biology of the Eastern Bluebird (read by Tom J. Cade) . Symposium: Avian Ecology in Grasslands, Chairman; John A. Wiens, Oregon State University Introductory Remarks by Chairman. Ronald A. Ryder, Colorado State University, Seasonal Fluctuations of Bird Populations on some Colorado Grasslands. William J. Maher, University of Saskatchewan. Growth Rates of Ground-nesting Passerine Birds at Matador, Saskatchewan, Canada. Paul H. Baldwin, Colorado State University. Feeding Dynamics of the Lark Bunting. Stephen G. Martin, Oregon State University. Territorial Quality and Polygny in the Bobolink. John L. Zimmerman, Kansas State University. Survival in the Grassland Sere: the DickcisseTs Adaptations for Opportunism. John A. Wiens, Oregon State University. Habitat Structure and Spatial Relationships among Grassland Birds. Arthur C. Risser, Jr., University of California, Davis. The Experimental Modification of Starling Reproductive Performance at Different Densities. Keith A. Arnold, Texas A&M University. Survival of Banded Great-tailed Grackles at College Station, Texas. Vivian R. Null, California State College, Hayward. Numbers, Species Composition, and Flight Patterns of Gulls near San Francisco Bay, California. Howard L. Cogswell, California State College, Hayward. Movements of Gulls within and among Local Populations near San Francisco Bay, California. C. W. Comer, Kansas State Teachers College, Emporia. Winter Activities of the Slate- colored Junco on the Ross Natural History Reservation. David A. Manuwal, University of California, Los Angeles. Ecology oj Cassins Anklet on Southeast Farallon Island. Eugene Eisenmann, American Museum of Natural History. Recent Increase and Range Extension of the White-tailed Kite in Middle America. Fred C. Sibley, Point Reyes Bird Observatory. Annual Nesting of the California Condor. Roland H. Wauer, Big Bend National Park. Density and Distribution of the Colima Warbler within the Chisos Mountains, Texas. James K. Baker, National Park Service. The Fluctuating Avifauna of Santa Barbara Island, California. Andrew J. Berger, LIniversity of Hawaii. The Nests and Eggs of some Hawaiian Birds. 350 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Richard D. Porter and Stanley N. Wiemeyer, Patuxent Wildlife Research Center. Re- productive Patterns in Captive American Kestrels. Jay H. Schnell, Tall Timbers Research Station. A Live-trapping and Recapture Technique for Red -tailed Hawks. Edmund A. Hibbard, North Dakota State University. Bird Populations of Successional Forest Habitats along the Missouri River in North Dakota. Douglas James and Steven H. Fritts, University of Arkansas. A Multivariate Analysis oj Indigo Bunting Habitat in the Southwestern Part oj its Breeding Range. Jed J. Ramsey, Lamar State College of Technology. Cattle Egrets, Buhulcus ibis, in Southeast Texas. Cene M. Christman, University of California, Berkeley. Pathologies of Slides at Scientific M ee tings. Moving Pictures. Harvey I. Fisher, Southern Illinois University. The Laysan Albatross on Midway. C. B. Schaughency, Chester, New Jersey. Some Birds oj Mexico. The Frame House Gallery, Louisville, Kentucky. A Bird in the Hand — A Bird in the Bush. ATTENDANCE Three hundred twenty nine members and guests were registered. Forty two states, four Canadian provinces and England were represented. From Arkansas: 3 — Fayetteville, Douglas A. James; Little Rock, Henry N. Halberg. Mrs. Henry N. Halberg. From Arizona: 4 — Flagstaff, Russell P. Baida; Tucson. Stephen M. Russell. Carl Tomoff, Charles Viers. From California: 53 — Berkeley, Gene M. Christman, Jane Durham, James Hunt, Ned K. Johnson, Robert Raikow; Bolinas, T. James Lewis, Fred Sibley, Boh Stewart; Carmel Valley, John Davis; Courtland, Mrs. Arvil Parker; Davis, Robert Ohmart, Arthur Risser, Jr.; Fillmore, Sidney Peyton; Hayward, Howard L. Cogswell. Mrs. Howard L. Cogswell; Hollywood, Don Bleitz; La Jolla, Miss Grenville Hatch; La Mesa, Jean W. Cohn; Long Beach, Hal Boley, Charles T. Collins; Los .Angeles, Cynthia Carey, Nicholas Collias, Elsie Collias, Ed N. Harrison, Lloyd Kiff, Martin Morton, Grace Nixon, Kenneth Stager, Jack C. Von Bloecker, Jr.; Malibu. Martine Vozan, Telford H. Work; Oakland, Mrs. Enid Austin, Vivian Null; Orinda, Tom Schulenherg; Reseda, David Manuwal, Mrs. David Manuwal; Richmond, Jack Gug- goh, Mrs. Jack Guggoh; Sacramento, M. D. F. Udvardy; Sun Diego, Gerald Collier, Michael Evans, Marjorie Mason; San Francisco, Laurence C. Binford. Robert T. Orr. Edgar Stone; San Jose, L. R. Mewaldt, Mrs. L. R. Mewaldt. John Mewaldt; San Pedro, Shirley Wells; Santa Barbara, Waldo G. Abbott; Stockton, M. Dale Arvey; Twenty-Nine Palms, James Baker; Upland, John Mortensen. From Colorado: 62 — Aurora, Lois Webster; Berthoud, Mrs. G. T. Cummings. Christian Muller, Mrs. Daniel Muller; Boulder, Carl Bock, Mrs. G. M. Booth, William Burt, Gene Elliott, Robbie Elliott, Karlo Hadow, Louise Hering, Mrs. Dorothy A. Herman. Richard Jones, Paul Julian, Mrs. Paul Julian, Terry A. May, David Norris, Mrs. Ralph Odell, Victor Smith, Mrs. Victor Smith, Olwen Williams; Colorado Springs, Richard G. Beidleman, Mrs. Nancy Greenleaf, Mrs. Helen Thurlow; Denver, Phyliss Caswell, William Eastnian, Thompson Marsh, Mrs. Thompson Marsh. Sadie Morrison, Mary Hope Robins, Miss Tohina Storrie, Donald Thatcher, Lynn Willcockson; Englewood, Merle Barbour; Evergreen, Winston W. Brockner, Mrs. Winston W. Brockner, Donald Malick; Fort Collins, Paul H. Bald- September 1970 Vol. 82, No. 3 FIFTY-FIRST ANNUAL MEETING 351 win. Clail Braun, Terry Cole, Phil Creighton, N. R. French, David Lupton, Wayne Marion, Carl Marti, Meredith Morris, Richard Olendoroff, Gary Packard, Helen Ryder, Raymond Ryder, Ronald A. Ryder, Mrs. Ronald A. Ryder, Gustav A. .Swan- sou; Grand Junction, William Davis; Greeley, Maynard .Stamper; La Junta, William Anderson, Bahette Cranson, Mrs. Robert Wolfe; Lakewood, William Rayall, Jr.; Longmont, Allegra Collister; Loveland, Jean Christensen, .Mr. 1. K. Robertson. From Connecticut: 6 — New Haven, l^eter Bottjer, Kendall Corbin, Andrew Ferguson, Charles G. Sibley, Mrs. Charles G. Sibley; Storrs, George A. Clark, Jr. From District of Columbia: 3 — Washington, Richard C. Banks, George E. Watson, Richard L. Zusi. From Florida: 1 — Tallahassee, Jay Schell. From Georgia: 2 — Athens, Kenneth P. Able, Sidney A. Gauthreaux, Jr. From Hawaii: 1 — Honolulu, Andrew J. Berger. From Idaho: 1 — Pocatello, Charles Trost. From Illinois: 12 — Blue Island, Karl Bartel; Carbondale, Harvey Fisher, Mrs. Harvey Fisher, David Hayward, Vernon Kleen, Hohn Krull; DeKalb, William Southern; Havana, Frank C. Belrose, Jr.; Lebanon, Ernest Willoughby; Macomb, Robert Beason, Edwin Franks, Mrs. Edwin Franks. From Indiana: 3 — Hanover, J. Dan Webster; Richmond, C. S. Snow, Mrs. C. S. Snow. From Iowa: 5 — Davenport, Maria Costa, Peter Peterson, Mrs. Peter Peterson; Grinnell, Helen Stewart, Mildred Stewart. From Kansas: 6 — Emporia, C. W. Comer; Hays, Charles Ely; Lawrence, Richard F Johnston, Jerome D. Robins; Manhattan, Ronald Case, John L. Zimmerman. From Kentucky: 1 — Richmond, A. L. Whitt, Jr. From Louisiana: 4 — Baton Rouge, George H. Lowery, Mrs. George H. Lowery; Shreve- port, Horace H. Jeter, S. 0. Williams HI. Erom Maryland: 9 — Baltimore, David G. Ainley, C. John Ralph; Elliott City, Earl Baysinger, Mrs. Earl Baysinger; Laurel, Richard Porter, Ghandler Robbins, Mrs. Chandler Robbins, Jeff Swinebroad; Suitland, James A. Bruce. From Massachusetts: 6 — Franklin, John Minot; Littleton, James Baird, Robert Baird; Middleboro, Paul Anderson, Mrs. Paul Anderson; South WeUjleet, Wallace Bailey. From Michigan: 6 — Ann Arbor, Robert W. Storer, Nancy White; East Lansing, George Wallace, Mrs. George Wallace; Mt. Pleasant, Harold Mahan; Pontiac, Daniel S. McGeen. From Minnesota: 11 — Duluth, Joel Bronoel, Mrs. Joel Bronoel, P. B. Hofslund; I * MoiUe, Mrs. Violet Nagle, Mrs. Pauline Wershofen; Minneapolis, Walter Breckenridge, Mrs. Walter Breckenridge ; South St. Paul, Thomas Savage, Mrs. Thomas .Savage; Stillwater, John Erickson, Mrs. John Erickson. From Missouri: 9 — Columbia, W. Reid Goforth; Kansas City, Erwin Klaas, Mrs. Erwin Klaas; St. Louis, Richard A. Anderson. Mrs. Richard A. Anderson, Margaret Feigley, Mrs. Joel Massis, James Mulligan, Lilliam Nagel. From Nebraska: 8 — Chadron, Mary Blinde, Doris Gates; Lincoln, Esther Bennett, Calvin Cink, Raymond Goldstein, Daniel Hatch, Alice Prososki; Omaha, Larry Holcomb. From New Hampshire: 1 — Manchester, Mrs. Robert P. Booth. From New Jersey: 15 — Cape May Point, Ernest A. Choate; Chester, Charles Schaugh- ency, Mrs. Charles Schaughency; Mountainside, Albert Schnitzer, Mrs. Albert Schnitzel' ; Newjoundland, Evamarie Townsend; Orange, Anne Wachenfeld; 352 THE WILSON BULLETIN September 1970 Vol. 82, No. 3 Princeton, Charlotte DuBois; Ramsey, Mrs. Eleanor Dater; Riverton, Kenneth Reynard, Mrs. Kenneth Reynard, George Reynard; W enonah, Edward Manners, M rs. Edward Manners; Westfield, Norman Pilling. Erom New Mexico: 2 — Las Cruces, Donald Caccamise, Ralph J. Raitt. From New York: 16 — Buffalo, Alice Ulrich; Ithaca, Susan M. Budd, Tom J. Cade, Mrs. Cyril Comar, Charles Leek, Carol Pearson, Olin S. Pettingill, Jr., Mrs. Olin S. Pettingill, Jr., W. John Richardson; New York City, Dean Amadon, Mrs. Dean Amadon, Walter Bock, Eugene Eisenmann, Lester L. Short; Rochester, Roland C. Clement; Waterloo, Jayson Walker. From North Carolina: 2 — Chapel Hill, Helmut C. Mueller; Raleigh, Nancy Mueller. From North Dakota: 1 — Fargo, Edmund A. Hibbard. From Ohio: 12 — Bowling Green, Elden W. Martin; Burton, Robert McCullough; Char- don, Marjorie Ramisch; East Liverpool, John Laitsch, Mrs. John Laitsch; Gambler, Robert Burns; Lakewood, William A. Klamm, Mrs. William A. Klamm; Oxford, David R. Osborne; Painesville, Mrs. Robert Booth; Ravenna, Mildred Daniels, Estrilla Daniels. From Oklahoma: 2 — Norman, Marsha Landolt, Robert B. Payne. From Oregon: 7 — Ashland, John O. Sullivan; Burns, Carroll D. Littlefield; Corvallis, Stephen Martin, John Rotenberry, John A. Wiens; Forest Grove, Vaughan A. Langman; Monmouth, Lowell Spring. From Pennsylvania: 5 — Chester Springs, Phillips B. Street; Newton, Lester Thomas, Mrs. Lester Thomas; Philadelphia, C. Chandler Ross; Pittsburgh, Kenneth C. Parkes. From Puerto Rico: 2 — Palmer, Cameron B. Kepler, Mrs. Cameron B. Kepler. From South Dakota: 3 — Rapid City, L. M. Baylor, Keith Evans, Nathaniel R. Whitney. From Tennessee: 5 — Elizabethton, Lee R. Herndon, Mrs. Lee R. Herndon; Gatlinburg, Arthur Stupka, Mrs. Arthur Stupka; Maryville, Ralph J. Zaenglein. From Texas: 6 — Austin, Gary Schnell; Beaumont, Jed Ramsey; Big Bend Natl. Park, Roland Wauer; College Station, K. A. Arnold; Dallas, Cecil Kersting; Huntsville, Ralph Moldenhauer. From Utah: 12 — Brigham City, Michael Long; Logan, Vivian Telford Anderson, Dick Burr, K. L. Dixon, Martha Lester, Mike Minock, Joe Platt, June Rushing, Richard Wilson, Janet Young; Salt Lake City, William Behle, Mrs. William Behle. From Virginia: 2 — Manassas, Mrs. Roxie Laybourne; JFilliamsburg, Mitchell A. Byrd. From Washington: 5 — Ellensburg, F. John Erickson, Donald F. Martin, Jared Verner, Mrs. Jared Verner; Seattle, Frank Richardson. From West Virginia: 3 — Inwood, Clark Miller; Morgantown, George A. Hall, Mrs. George A. Hall. From Wisconsin: 2 — Madison, John Watson; Viroqiia, Margarette Morse. From Wyoming: 1 — Laramie, Kenneth Diem. From Alberta: 1 — Calgary, M. J. Myres. From Ontario: 3 — Aurora, R. G. Brown; Newmarket, Reg E. Chandler, Mrs. Reg E. Chandler; Toronto, William W. H. Gunn. From Quebec: 1 — Montreal, David Nettleship. From Saskatchewan: 1 — Saskatoon, William Maher. From England: 1 — Manchester, John Mosher. Also attending: Larry DeBord, Jimm Gessaman, Douglas Vogeler. This issue of The Wilson Bulletin was published on 30 September 1970 Editor of The Wilson Bulletin GEORGE A. HALL Department of Chemistry West Virginia University Morgantown, West Virginia 26506 Editorial Advisory Board William C. Dilger Douglas A. James William A. Lunk Andrew J. Meyerriecks Helmut C. Mueller Robert W. Nero Kenneth C. Parkes Glen E. Woolfenden Ornithological Literature Editor Peter Stettenheim Box 79, Plainfield, New Hampshire 03781 Suggestions to Authors Manuscripts intended for publication in The Wilson Bulletin should be neatly type- written, double-spaced, and on one side only of good quality white paper. Tables should be typed on separate sheets. Before preparing these, carefully consider whether the material is best presented in tabular form. Where the value of quantitative data can be enhanced by use of appropriate statistical methods, these should be used. Follow the AOU Check-list (Fifth Edition, 1957) insofar as scientific names of United States and Canadian birds are concerned unless a satisfactory explanation is offered for doing otherwise. Use species names (binomials) unless specimens have actually been handled and subsequently identified. Summaries of major papers should be brief but quotable. Where fewer than five papers are cited, the citations may be included in the text. All citations in “General Notes” should be included in the text. Follow carefully the style used in this issue in listing the literature cited; otherwise, follow the “Style Manual for Biological Journals” (1964. AIBS). Photographs for illustrations should be sharp, have good contrast, and be on gloss paper. Submit prints unmounted and attach to each a brief but adequate legend. Do not write heavily on the hacks of photographs. Diagrams and line drawings should be in black ink and their lettering large enough to permit reduction. Authors are requested to return proof promptly. Extensive alterations in copy after the type has been set must be charged to the author. Notice of Change of Address If your address changes, notify the Society immediately. Send your complete new address to the Treasurer, William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. He will notify the printer. The permanent mailing address of the Wilson Ornithological Society is; c/o The MUSEUM of Zoology, The University of Michigan, Ann Arbor, Michigan 48104. Persons having business with any of the officers may address them at their various addresses given on the back of the front cover, and all matters pertaining to the Bulletin should be sent directly to the Editor. Plan now to participate in THE FIFTY-SECOND ANNUAL MEETING to be held at Dauphin Island, Alabama 22-25 APRIL 1971 IMPORTANT NOTICE FOR SUBSCRIBERS TO THE WILSON BULLETIN The annual subscription price (for non-members and institutional subscribers) has been increased from $6 to $10. This increase takes effect for all subscriptions to Volume 83, 1971. MUS. COMP. ZOOL LIBRARY PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. . MORGANTOWN, W. VA. VOL. 82, NO. 4 DECEMBER 1970 PAGES 353-486 The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President— William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. First Vice-President — Pershing B. Hofslund, Dept, of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812. Second Vice-President — Kenneth C. Parkes, Carnegie Museum, Pittsburgh, Pennsylvania 15213. Secretary — ^Jeff Swinebroad, 8728 Oxwell Lane, Laurel, Maryland 20810. Treasurer — William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. Elected Council Members — C. Chandler Ross (term expires 1971) ; Ernest P. Edwards (term expires 1972) ; Elden W. Martin (term expires 1973). Membership dues per calendar year are: Active, $8.00; Sustaining, $15.00; Life memberships, $200 (payable in four installments). The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new books; members and friends are invited to maintain the fund by regular contribution, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 104 periodicals as gifts and in exchange for The Wilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer (small sums in stamps are acceptable). A complete index of the Library s holdings was printed in the September 1952 issue of The Wilson Bulletin and newly acquired books are listed periodically. The Wilson Bulletin The official organ of the Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Morgantown, West Virginia. The subscription price, both in the United States and elsewhere, is $10.00 per year. Single eopies, $2.50. Subscriptions, changes of address and claims for undelivered eopies should be sent to the Treasurer. Most back issues of the Bulletin are available (at $2.&u eaeh) and may be ordered from the Treasurer. Speeial prices will be quoted for quantity orders. All articles and communications for publications, books and publications for reviews should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, Michigan. Second class postage at Lawrence, Kansas, U.S.A. 66044 Allen Press, Inc., Lawrence, Kansas 66044 O. ft. ^ ' THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society VoL. 82, No. I December 1970 Pages 353-486 CONTENTS Males in Breeding Plumage of the Races of the Dendroica CORONATA Complex, Watercolor by Theodore R. Miley facing page 355 Geographic Variation in the Dendroica coronata Complex John P. Hubbard 355 Nesting Bird Ecology of Four Plant Communities in the Missouri River Breaks, Montana Kenneth C. Walcheck 370 Oldsquaws Nesting in Association with Arctic Terns at Churchill, Manitoba Roger M. Evans 383 Seasonal Changes in Flocking Behavior of Starlings as Correlated with Gonadal Development . G. James Davis 391 Spatial Disorientation in Birds A. D. Herbert 400 Breeding Populations of Tule White-fronted Geese in Northwestern Alaska Bob Elgas 420 Winter Dominance Relationship in Black-capped Chickadees Jonathan E. Hartzler 427 A Comparative Study of Nesting Forster’s and Black Terns Robert D. Bergman, Peter Swain, and Milton W . Weller 435 Breeding Biology of American Coots in Iowa Leigh H. Eredriekson 445 Nesting Success and Mortaeity of Nestlings in a Cattle Egret Colony Julian L. Dusi and Rosemary T. Dusi 458 General Notes MALLARD-CRKKN-WINGKD TEAL ASSOCIATIONS IN SOUTHERN WISCONSIN Cart H. Nellis, James J. Zohrer, and Daniel W . Anderson 461 A SECOND SWALLOW-TAILED KITE RECORD EOR TRANS-PECOS TEXAS Roland W' . Waner 462 GIANT WATERBUG IN AN OWL PELLET Walter Kingsley Taylor 462 EGG TRANSPORT RECORDED FOR THE RED-BELLIED WOODPECKER Graham C. Hickman 463 EASTERN PHOEBE NESTING IN OLD BARN SWALLOW NEST .... Hamion P. Weeks, Jr. 463 HERMIT WARBLER IN MISSOURI David A. Easterla 464 YELLOWTiiROAT CAUGHT IN COMMON BURDOCK Richard D. Browii 464 THE DOUBLE-SCRATCH IN THE GENUS POOECETES Walter Kingsley Taylor 465 COMMON CRACKLE KILLS CEDAR WAXWING IN AIR Erma ]. Fisk 465 FIRST NESTING COLONIES OF THE LARK BUNTING IN MISSOURI David A. Easterla 465 Ornithological News 467 Ornithological Literature 469 Lotus and Margery Milne, Birds of North America, reviewed by Olin Sewall Pettingill, Jr.; Robert H. Giles, Jr., editor. Wildlife Management Techniques, reviewed by D. A. Lancaster; Theed Pearse, Birds of the Early Explorers in the Northern Pacific, reviewed by Warren B. King; J. A. Baker. The Hill oj Summer, reviewed by Louise deK. Lawrence; Helmut K. Buechner and Jimmie H. Buechner, editors. The Avifauna^ of Northern Latin America, reviewed by George A. Hall. The Wilson Ornithological Society, Officers and Committee Chairman 474 Index to Volume 82, 1970 Membership List (Supplement to Vol. 82, No. 4) 475 • ' -r .■*. ik L \ V l'" lUi •2. Males in breeding plumage of the races of the Dendroica coronata complex (from top): D. c. coronata, D. c. auduboni, D. c. nigrifrons, D. c. goldmani. Watercolor by Theodore R. Miley. GEOGKAPHIC VARIATION IN THE DEN D ROIC A CORONATA COMPLEX John P. Hubbard The Dendroica coronata ( L. ) complex consists of the Myrtle Warbler I D. coronata] , which breeds in the boreal forests of North America, and Audubon’s Warbler [D. auduboni Townsend), which breeds in the forests of western North America. Although the two are generally regarded as distinct species, they intergrade in southwestern Canada and should be considered as a conspecies, or better, as two semispecies (Hubbard, 1969). Besides the nominate forms, one other has been named in the Myrtle group ( i.e., hooveri McGre gor ) and three in the Audubon group ( i.e., memorabilis Oberholser, nigrijrons Brewster, and goldmani Nelson). The last revisions were by Godfrey (1951) in the coronata group and by Oberholser (1921) in the auduboni group. The present paper is the outgrowth of a comprehensive analysis of geographic and other types of variation (Hubbard, 1967), which was done prior to study of the interbreeding of the two semispecies groups ( Hubbard, 1969). My object here is to describe salient features of the geographic varia- tion in each of these groups and to assess the named forms (no new forms are proposed). For a more detailed review of variation in this complex the I'eader is referred to my 1967 work, available from University Microfilms, Ann Arbor, Michigan. In extending formal, subspecific recognition to populations I followed the suggested criteria of Mayr et al. (1953 ), in accepting as valid those entities that are separable inter se on a 75 per cent from a near 100 per cent ( or 90 from 90 per cent ) basis. A further requirement is that the probability of correct segregation within a random sample be 95 per cent or better. While recognizing the need for certain minimum and arbitrary standards in the application of formal names to populations, I also feel that in some cases what might be termed “infra-subspecific” variation can be usefully singled out. For example, by being able to identify distinctive extremes that char- acterize certain populations one may gather information on dispersal, molt cycles, and other aspects of the biology even though the populations in question are not “good” subspecies. Such infra-suhspecific entities can he designated by breeding range rather than by a formal name and thus provide the practical benefits of the subspecies concept without further burdening scientific nomenclature. 355 356 THE WILSON BULLETIN I)cceiJil)er 1970 Vol. 82, No. 4 Fig. 1. Geographic samples used in analysis of mensural characters in the Dendroica coronata complex. Numhers 1 through 17 are coronrita group and 18 through 42 the (tuduhoni group (nominal designations of numhers in Table 1). John P. Hubbard VARIATION IN DENDROICA CORONATA 357 MATERIALS AND METHODS This study is based on 350 specimens in winter plumage, 503 juveniles (none available of goldniani), and 2,(X)9 specimens taken in the breeding season. The lireeding season is arbitrarily considered to l)e 1 June (15 May in the Pacific Northwest and northern- most North America) through the time of the end of the postnuptial molt and applies to specimens taken in suitable breeding areas. For various analyses specimens were segregated into juveniles (includes both sexes), first-year males (i.e., males that have completed the postjuvenal but not the first postnuptial molt), adult males (i.e., males that have completed at least one postnuptial molt), and females. First-year males were found to be about 90 per cent separable from adults on the basis of their generally browner (and more worn) remiges, rectrices, and especially primary coverts and alular feathers (verified by juveniles and skull-aged specimens) ; adults have these feathers more blackish, often with grayish edgings, and less worn. Although similar differences exist in females, the segregation of age classes was not attempted because the differences are much more subtle and less consistent. Breeding specimens within each of the two semispecies were segregated into the smallest geographic samples possible for a preliminai'y multivariant analysis of linear measure- ments, with subsequent recombination of certain samples to better study and present the data (Fig. 1). Linear measurements used were lengths of wing (chord), tail, culmen (nostril to tip), and tarsus, all but the last using established methods. The tarsus was measured from the posterior depression of the tibio-metatarsus joint to the proximal base of the hallux, provided that the latter was positioned 90 ± 45 degrees relative to the tarsometatarsus ( positions outside that range were found to alter tarsus length by 1 to 2 mm). In spite of these qualifications most specimens were measurable for tarsus length, and this method of measurement was found to be faster than and as accurate as the traditional one. Wing and tail length were found to be strongly correlated, and as a result only wing length was used in the mensural analysis on an absolute basis. Body weight of breeding males was also used to compare samples, those of females being excluded as too variable due to variation in weight of gonads and gonadal products (Hubbard, 1967). Body weight was found to vary independently of the linear measure- ments used above and is treated separately. The amount of white in each rectrix was scored as follows: a very small spot or narrow marginal edging (0.125) ; a small spot or narrow marginal blotch (0.25) ; a medium spot or small marginal blotch (0.5) ; a large spot or medium marginal blotch (0.75) ; or a large marginal blotch (1.00). The values for each pair of rectrices were summed to obtain the score of white in the tail of each specimen and these were used to compare sample means. Statistical procedures follow Steel and Torrie (1960) and other specified sources. Variances were calculated for samples of six or more specimens, and differences between sample measurements are accepted as significant when at or greater than the 0.05 level of prohability. RESULTS AND DISCUSSION Coronata Group This group breeds from New' England, eastern New York, southern Ontario, central Michigan, southern Manitoba, southern Saskatchewan, central Allierta, northern British Columbia, and southeastern Alaska northw'ard to tree line (Fig. 1 ) and is migratory throughout its breeding range. Intergradation with THE WILSON BULLETIN December 1970 Vul. 82, No. 4 0 C ( ) i>C)0 the auduhoni group occurs in southeastern Alaska, central and eastern British Columbia, and southwestern Alberta and is discussed elsewhere ( Hubbard, 1969). Within the coronata group I found geographic trends in the variation of both color and pattern of plumage and in mensural characters. Plumage characters which vary are extent of black in the breast of breeding males, color and extent of streaking on the upperparts of breeding females, the color of the upperparts of winter-plumage specimens, and extent of white in the outer rectrices. Mensural characters which vary are body weight of breeding males and lengths of tarsus and wing. Purported differences in the hue of the yellow rump (Oberholser, 1918), color of the upperparts of juveniles 1 Oberholser, 1918; Godfrey, 1951), and of the extent of dorsal streaking in winter plumage ( Godfrey, 1951 ) were not substantiated. In breeding-plumaged males the black on the breast varies from streaking to solid, with the former extreme predominating in the northwest ( Alaska, Yukon, and British Columbia) and the latter in Labrador-Newfoundland. In northwestern males (81 specimens in 3 samples) 56 to 66 per cent were streak-breasted and the remaining 34 to 44 per cent were mottled with black on the breast. In the Prairie Provinces the streak-breasted type composed 20.5 per cent in a sample of 29 males, while 79.5 per cent were mottle-breasted. Larther east, 10.5 per cent of 151 males were streak-breasted, 74.7 per cent mottle-breasted, and 14.8 per cent solid-breasted, except in Labrador-New- foundland (14 males ) where none was streak-breasted and 50.0 per cent each were mottle- and solid-breasted. Prom these data two points can be made: one, no geographic area can be characterized by a single breast type; and, two, only solidly black-breasted males are confined to an area discrete enough to be useful in reliably segregating specimens. Thus, solid-breasted males may be said to originate in eastern North America, east of the Prairie Provinces, with a confidence level of 100 per cent. In my sample of males some 15.0 per cent are of this type and can thus be assigned geographically on this character. In breeding-plumaged females the upperparts vary from light brown (occiput light gray) with light streaking to dark brown with heavy streaking; the light brown type predominates in the west and the dark brown in the east. In northwestern females (39 specimens in 3 samples) the light brown type composed 72.7 to 76.5 per cent, while zero to 5.0 per cent were dark brown and 22.3 to 23.5 per cent were intermediate. In Alberta the light brown type constituted 68.0 per cent of 25 specimens and 32.0 per cent were intermediate. Larther east the light brown type was 4.9 to 12.5 per cent (73 specimens in 3 regional samples), while 65.8 to 68.8 per cent were dark brown and 18.7 to 29.3 j)er cent were intermediate. While most specimens in regional samples John V. Hubhartl VARIATION IN DENDROICA CORONATA 359 fall into one or the other extreme of this character and show a geographic tendency in the trend of variation, 23.5 to 34.2 per cent of the specimens in each sample fall in the opposite extreme and intermediate categories. This means that no sample or area can he characterized by a single plumage type. Furthermore, of the two extremes oidy the dark brown type is sufficiently limited in its distribution and frequency to be useful in reliable segregation of specimens. Thus, females with dark brown, broadly streaked upperparts may be attributed to North America, east of Alberta; in my samples the con- fidence level of this segregation is 97 per cent, and 37 per cent of female specimens may be identified in this way. In the color of the upperparts winter-plumaged specimens vary from light to dark brown, with or without a rufescent wash. Study of this character is made difficult because of the problem of obtaining winter specimens from known breeding areas. In my analysis I used 40 specimens taken in late summer and autumn, and segregated by sex and age classes, from Alaska and northwestern British Columbia, compared to 80 from southeastern Canada and the adjacent United States. In the northwestern sample 92.5 per cent of the specimens fell into the categories of light, rufescent brown or dark brown, while the remaining 7.5 per cent were either light brown or dark, rufescent brown. By comparison 68.7 per cent of the eastern speeimens fell into the first two categories ( i.e., light, rufescent brown and dark brown ) , whereas 12.5 per cent were light brown and 18.8 per cent were dark, rufescent brown. These comparisons show different frequencies of color types between the two samples, but complete overlap exists among the types. The degree of overlap is such that reliable segregation of specimens on a geographic basis is not possible. The final plumage character in which I found geographic variation is the amount of white in the outer rectrices, with the average scores in north- western populations being higher than those in more easterly ones. In adult males from Alaska, the Yukon, British Columbia, and MacKenzie the values are 3.2 to 3.6, compared to 3.0 to 3.1 in more eastern samples. In first-year males from the northwestern area the values are 2.7 to 3.2 compared to 2.5 to 2.7 eastward except for 2.9 on the western side of Hudson Bay. In females the northwestern values (excluding MacKenzie which is 2.5) range from 2.7 to 2.8, compared with 2.4 to 2.6 eastward except for 2.8 in southern Manitoba. The differences are relatively minor and overlap occurs in means of first-year males and females, as well as in individuals of all samples. Further, some inconsistency exists in the area from MacKenzie to Hudson Bay, perhaps due to introgression with auduhoni. Thus, in spite of trends in average differences no effective separation of populations is possible on the basis of this character. 360 THE WILSON BULLETIN December 1070 VoU 82, No. 4 Table 1 Wing Length (mm) in Bheeding Samples of the dendroica coronata Complex Semispecies grouiis Adult ma les First -year males Females Sample no. mean S.D. no. mean S.D. no. mean S.D. Coronata group 1. Alaska 14 77.1 1.8 23 75.3 1.3 16 72.9 1.1 2. Yukon 13 76.5 1.6 12 74.5 1.3 9 72.3 0.9 3. Northwest British Columbia’ 13 76.8 1.1 24 75.0 1.4 27 71.4 1.2 4. MacKenzie 9 74.7 0.8 7 72.7 0.8 9 69.7 1.1 5. Central Alberta’ 8 74.1 1.6 9 72.4 1.7 9 69.0 1.8 6. Manitoba 5 73.0 — 12 72.0 1.6 11 68.4 1.7 7. West .lames Bay 9 74.3 1.7 7 72.5 1.3 8 69.3 0.9 8. East James Bay 6 74.9 1.5 11 71.8 0.9 14 69.3 1.5 9. Labrador 12 74.5 1.5 4 71.8 — 12 69.7 1.4 10. Central Ontario 11 73.9 1.7 15 71.7 1.4 16 69.0 2.4 11. Quebec 9 74.0 1.2 19 72.6 1.2 16 69.3 1.1 12. Newfoundland 6 74.7 2.4 8 72.5 1.6 10 70.1 2.3 13. New Brunswick 5 73.0 ■ 12 71.3 0.9 13 68.7 1.5 14. Nova Scotia 9 74.1 2.0 10 72.4 1.2 10 67.9 1.3 15. Michigan 12 73.0 1.0 20 71.7 1.7 9 68.3 0.7 16. Southeast Ontario 11 73.3 1.5 10 71.6 2.0 8 68.3 1.0 17. Northeast United States 7 74.1 1.3 15 72.1 1.9 13 68.6 1.3 Auduboni group 18. Central British Columbia” 10 76.5 1.3 15 74.5 1.6 2 72.6 19. Southern British Columbia 8 77.7 1.4 12 75.2 1.3 18 71.6 1.6 20. Northwest Coast 13 76.6 1.3 21 74.0 1.4 24 71.4 1.4 21. Cascades 13 78.0 1.6 17 75.1 1.4 12 73.3 1.6 22. Cypress Hills 6 78.0 1.3 7 77.3 1.4 11 73.5 1.7 23. Northeasl Oregon 14 77.9 1.6 10 76.3 1.2 7 73.8 0.8 24. Idaho 7 79.4 1.6 18 75.9 1.5 22 73.3 1.0 25. Northwest California 12 79.0 1.5 14 76.4 1.9 17 73.9 1.3 26. Northeast California 14 79.6 1.9 17 76.4 1.1 10 73.4 1.9 27. Sierra Nevada 30 79.7 1.5 41 77.1 1.8 47 74.4 1.8 28. Western Nevada 13 80.3 1.8 9 76.8 0.8 8 74.8 1.6 29. Northeasl Nevada 7 80.5 2.3 10 77.1 1.6 12 74.4 1.6 30. San Bernardino Mts. 17 79.7 1.3 12 78.0 2.1 10 74.3 1.8 31. San Jacinto Alts. 7 80.0 1.3 7 76.5 1.2 12 76.6 1.4 32. Southern Nevada 8 80.0 1.4 8 77.8 1.7 10 73.5 1.8 33. Utah 14 80.3 1.2 19 77.5 1.3 15 74.3 2.0 34. Northwest Wyoming 14 80.2 1.2 16 77.6 1.4 27 74.6 1.5 35. Black Hills 17 81.4 0.5 8 78.6 1.0 13 76.5 1.4 36. Southern Rockies 31 80.7 1.8 22 77.9 1.2 20 75.1 1.6 37. Central Arizona 15 80.7 1.3 12 78.8 1.1 11 76.0 1.8 38. Alogollon Alts. 11 80.8 1.9 9 78.9 1.4 10 75.4 1.5 1 InterKrades toward (iiidiihoni. 2 Intergrados toward coronata. John P. Hubbard VARIATION IN DENDROICA CORONATA 361 Table 1 (Cont’d. ) Seniispecies groups Sample Adult males First -year males Females no. mean S.D. no. mean S.D. no. mean S.D. Aiiduboni group (Continued) 39. Santa Catalina Mts. 18 81.8 1.7 27 79.5 1.4 19 76.4 1.8 40. Chiricahua Mts. 10 81.1 0.6 9 79.3 1.8 10 77.3 1.4 41. Sierra Madre Occidental 35 83.0 2.4 20 80.0 1.2 24 77.8 2.2 42. Chiapas-Guatemala^ 9 84.4 1.6 6 81.3 1.5 11 78.9 1.5 3 Includes specimens taken throughout the year. Mensural variation. — In analyzing body weights I was hampered by the lack of data, and conclusions are necessarily tentative. In comparisons of the only two sizable samples, I found a significant difference to exist between the means of eight males from Alaska (weight 13.5 ± 0.7 grams) and that of 13 from Michigan (weight 11.8 ± 0.4 grams). Among the few other weights available, those from Ontario and the northeastern United States were similar to the Michigan series and those from the Yukon and northwestern British Columbia were similar to the Alaskan ones. However, three weights from Quebec are intermediate (range 12.4 to 13.1 grams), which may suggest that weight increases from south to north rather than just northwestward. Ob- viously more data are needed to properly assess this character. For the tarsus a slight increase in mean length occurs from southern Canada and the adjacent United States northward to Labrador-Newfoundland on the east and Alaska-Yukon-British Columbia on the west, although locally the variation becomes mosaic rather than geographic in distribution. The means in southern areas are 16.9 to 17.7 mm in males compared to 17.5 to 18.1 mm in the northwest and 17.9 to 18.2 mm in Labrador-Newfoundland (females average smaller in size but show parallel trends). No reliable segregation of populations is possible on the basis of this measurement because of overlap and the slight differences involved. One finds that wing lengths of populations from the northwest (Alaska, the Yukon, MacKenzie Delta, and northwestern British Columbia) average larger than those to the east (Table 1). In adult males the means are 76.5 to 77.1 mm in the northwest and 73.0 to 74.9 mm to the east; in first-year males 74.5 to 75.3 mm in the northwest, 71.3 to 72.7 mm to the east; and in females 71.4 to 72.9 mm to 67.9 to 70.1 mm. I compared the group of easterly specimens with that from the northwestern and found that the separability in adult males (east versus northwest) is 70.7 per cent from 20.6 per cent, in first-year males 94.3 per cent from 36.9 per cent, and in females 91.1 per cent from 30.6 per cent. This degree 362 THE WILSON BULLETIN December 1970 Vol. 82. No. 4 of separability (confidence level 95 per cent) falls far short of the 75 from ca. 100 per cent (or 90 from 90 per cent) levels suggested by Mayr et al. (1953), and even on a less reliable basis of segregation (confidence level 75 per cent) the maximum separability is still only 89.5 to 83.1 per cent in easterly specimens and 61.7 to 86.1 per cent in the northwestern ones. Obviously separation of populations of wing length is not possible in the coronata group on a reliable and large-scale basis. Summary of variation and nomenclatural conclusions. — This review of geographic variation reveals the existence of several characters in the coronata group which reliably distinguish populations ( confidence level of 95 per cent or more), including longer wing in northwestern North America, and shorter wing, more extensively black breast in breeding males, and darker brown upperparts with heavier streaking in breeding females in more easterly North America. Other characters show minor differences, overlap, or other factors which negate their value in separation of populations, and include the color of the upperparts in winter plumage, amount of white in the outer rectrices, weight (data incomplete and inconclusive), and tarsus length. The reliable characters, even when combined (on the basis of random association ) , do not produce a sufficient level of separability to justify subspecific recognition of two populations, i.e., at least 75 per cent from about 100 per cent (or 90 from 90 per cent). In eastern populations the segregation by breeding plumage characters and wing length is 75.5 per cent in adult males, 96.1 per cent in first-year males, and 97.1 per cent in females, com- pared to 20.6 per cent, 36.9 per cent, and 30.6 per cent in the respective categories in northwestern populations, which are solely separable by wing length. Thus the separation of the latter population as a formal subspecies is unwarranted, and the name hooveri (McGregor, 1899) is considered a synonym. Nevertheless, the fact remains that the specified portions of the specimens from the two areas are reliably separable, and as segregation of such specimens may be of value, it is provided for in the key included in this work. Auduhoni Group The breeding range of this group is from central British Columbia, southern Alberta, and extreme southwestern Saskatchewan southward to northern Baja California, central Durango, and westernmost Texas, with a disjunct, resident population in extreme southeastern Chiapas and the adjacent highlands of Guatemala (Fig. 1). Except for the last, all populations are thought to be migratory, or at least are not known to be resident. Geographic variation exists in plumage color and pattern and in measurements. Plumage variation. — In breeding plumage, males from north of the Mexican border are gray above streaked with black, and white below with the breast Jolin P. Hubbard VARIATION IN DENDROICA CORONATA 363 streaked to solidly black. The loral and anteriormost auricular areas are blackish, and the areas posterior to the auriculars and posterior to the yellow crown patch are gray or grayish white. Over much of the western United States, southwestern Canada, and Baja California this plumage varies only slightly, with males from the Southern Rockies and Black Hills southward averaging somewhat more extensively black on the underparts than those to the north and west. The increase in extent of black is gradual over most of this extensive area, hut in the southernmost Southwest a marked increase occurs in the extent of black not only on the underparts hut also on the sides of the head and in the dorsal streaking as well. This increase is most apparent in adult males of the Chiricahua and Huachuca Mountains of Arizona, hut it also exists in first-year males from those areas and in males from northward to the Mogollon Plateau of Arizona and New Mexico ( and occasionally farther ) . In the increased melanism specimens from the two Arizona mountain areas often are intermediate between more northern popu- lations and those of the Sierra Madre Occidental. The latter are even more extensively black below, with heavier dorsal streaking, more blackish heads (lores, forehead, auriculars), and have the post-coronal and post-auricular patches whitish rather than grayish in color. Except for narrow intergrada- tion through the Chiricahua and Huachuca Mountains, the Sierra Madrean population shows a discontinuity with both northern and southern populations in characters of the male breeding plumage. Also distinctive is the resident population of Chiapas and Guatemala, in which males in breeding plumage are solidly black above, or black with a few gray streaks or smudges, with the post-coronal and post-auricular patches markedly white. The underparts are somewhat less extensively black than those of Sierra Madrean males. In winter plumage adult males from north of the Mexican border have the upperparts extensively gray, washed with light to moderately dark-brown, and the black marking of the underparts (obscured by buff tips in fresh plumage ) are in the form of spots or mottling. First-year males are browner, less gray above and have the ventral black markings as streaks. Females resemble first-year males but are more diffusely and less darkly streaked and in first-year plumage have reduced or no yellow in the throat. North of the southernmost Southwest little geographic variation exists in these plumages, although adult males become slightly more extensively black below as one progresses southward. In southern Arizona, and at least occasionally farther northward, occurs a definite shift toward the winter plumages that char- acterize the birds of the Sierra Madre Occidental, with the populations of the Chiricahua and Huachuca Mountains constituting intergrades in winter j)lumages between the Sierra Madrean populations and those to the north. 364 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Adult males in winter plumage from the Sierra Maclre Occidental are more extensively gray above with heavier black streaking than those from farther north, and the uneven brown wash that may he present is darker brown. The underparts are much more extensively black ( with a variable buff wash in fresh plumage) and the face is blackish. Lirst-year males and females are darker brown above, heavier streaked, and more extensively black below than their northern counterparts. Specimens of this population are highly separable from those farther north, except for a few of the intergrade specimens from southernmost Arizona. Also distinct and highly separable in winter plumage is the population of the Chiapas-Guatemalan area. Adult males differ from all others in having the winter plumage identical to the breeding plumage, thus lacking any trace of buff or brown. Lirst-year males and females resemble each other and their counterparts from the Sierra Madre Occidental, differing from the latter in their more richly brown, less sooty upperparts and more extensive streaking on the occiput. Lemales in breeding plumage show a pattern of geographic variation that parallels that of the breeding plumage of males and winter plumages. The same pattern of geographical variation also exists in the juvenal plumage as far as is known, but in the absence of specimens from the Chiapas-Guatemalan area the situation there remains to be clarified. In each of these plumages no significant geographic variation exists in populations north of the Mexican border except in southernmost Arizona (occasionally elsewhere in the South- west ) , where intergradation from northern plumage types toward that of the Sierra Madre Occidental occurs. Lor example, north of the intergrade area the upperparts of juveniles vary from light gray to huffy brown and the blackish streaking is narrow above and below. In the Sierra Madre Occidental the upperparts are a darker, more rufescent brown, lacking any grayish cast, and the streaking is darker, broader, and more extensive. Interestingly, the Sierra Madrean juveniles are virtually identical to those of the coronata group except for being more extensively streaked above and relatively larger in size. I presume that Chiapas-Guatemala juveniles will be found to be similar to those of the Sierra Madre Occidental. Geographic variation was found to exist also in the amount of white in the outer rectrices. North of the Mexican border the average scores of white in the tail of 14 samples showing no introgression with coronata were 4.9 to 5.1 in adult males, compared to 4.6 in the Sierra Madre Occidental and 4.4 in the Chiapas-Guatemalan area. In first-year males showing no intro- gression from the north the values are 4.2 to 4.7, compared with 3.8 in both the Sierra Madre Occidental and Chiapas-Guatemalan area; females from the respective areas score 3.7 to 4.6, 4.3, and 3.8. These figures show Jolin P. Hubbard VARIATION IN DEN L) ROIC A CORONATA 365 that males of the Mexican-Guatemalan area average less white in the tail than those from farther north, hut in females consiclerahle overlap exists. No effective separation of populations is possible on this basis because of the amount of individual variation. Mensural variation. — In the auduboni group at least local geographic trends are evident in body weight and lengths of culnien, tarsus, and wing. Slightly lesser values of weight are evident in 4 of 5 western United States samples (range of means 11.9 to 12.2, ± 0.7 to 1.0 grams) compared to 5 Rocky Mountain and Southwest samples (range of means 12.5 to 13.0, ± 0.6 to 1.5 grams), but differences are not significant and one western sample (northwestern California — 12.6 ± 0.6 grams) overlaps the eastern range. The Sierra Madre sample ( mean 12.7 ± 0.7 grams) and the one Guatemalan weight ( 13.0 ) are similar to more northern values and suggest a general homogeneity in this character in the auduboni group. Much of the variation in culmen length in the auduboni group is mosaic rather than clinal in nature, although certain populations are distinguishable compared to others. For example, in the Chiapas-Guatemalan area culmen length averages significantly larger (value 7.9 ± 0.2 mm in females and first-year males, 8.1 ± 0.1 mm in adult males) than in the Sierra Madrean population (females 7.2 ± 0.3 mm, males 7.4 ± 0.2 mm). Among the northern populations values vary widely (7.1 to 7.9 in females, 7.1 to 8.1 mm in males), but the pattern of variation is mosaic and no effective separation is possible inter se or when compared with more southerly populations. A gradual dine of increasing tarsus length exists from the north to the south, but as in culmen length local digressions and mosaic variation are present. For example, minimum values are in the Northwest Coast sample ( 17.7 to 18.0, ± 0.4 to 0.5 mm, depending on age and sex ) compared to mixi- mum values (18.9 to 19.4, ± 0.5 to 0.6 mm ) which occur in the Chiapas- Guatemalan area. Because of intergradation, overlap, and variability, no segregation of populations is possible on this basis. A generally orderly and gradual dine of increase of wing length occurs from the Northwest Coast southward to the Chiapas-Guatemalan area (Table 1 ) . Differences in the means of these two extreme areas are 7.3 to 7.8 mm and are highly significant, but because of the gradual nature of intergradation, no line can be made that will separate adjacent populations on a reliable and large-scale basis. Even when populations from geographic extremes are compared one finds that separation is not highly effective. For example, the values in the Chiapas-Guatemalan sample average larger than all other auduboni samples, hut no significant differences exist between that sample and those from the Sierra Madre Occidental, Southwest, Southern Rockies, and the Black Hills. North of the Mexican border the effective separation of 366 THE WILSON BULLETIN December 1M70 Vol. 82, No. \ populations is equally untenable because of the very broad overlap, and the small average differences between extremes. Interestingly, I found no differences between migratory and non-migratory populations in relative lengths of the “wingtip” ( i.e., the ratio of the length of the primaries posterior to the tips of the secondaries on the folded wing to the length of the total wing.). Lor example, this ratio is 24.5 per cent in adult males of the resident Chiapas-Guatemalan population compared to 24.1 per cent in the highly migratory Black Hills population. Summary of variation and nomenclatural conclusions. — This review of geographic variation reveals the existence of plumage characters which reliably and on a large scale distinguish several populations at the level of formal subspecies. These characters include the extent of black in male plumages, color of the upperparts and amount of streaking in breeding, winter, and juvenal plumages, and the color of the post-auricular and post-coronal patches in breeding males. These characters involve stepped or broken dines of in- creasing melanins in tbe plumage ( decreasing in tbe post-auricular and post- coronal patches ) from north to south. Clines of increasing tarsus and wing lengths occur over the same area but no steps or breaks exist that permit effective separation of adjacent (and many distant) populations. Also the weak dines or locally mosaic variations in the amount of white in the outer rectrices, body weight, and culmen length are generally ineffective in separat- ing most populations although the last effectively separates breeding birds of the Chiapas-Guatemalan area from those of the Sierra Madre Occidental. Populations meriting formal, subspecific recognition are goldmani (Nelson. 1897 ), resident of the Guatemalan highlands and adjacent Chiapas ( Lig. 1. sample 42); nigrifrons (Brewster, 1889), breeding in the Sierra Madre Occidental of Chihuahua and Durango (Lig. 1, sample 41); and auduboni (Townsend, 1837), breeding from Baja California and the Southwest north- ward (Lig. 1, samples 18 through 40), intergrading with the preceding in the Chiricahua and Huachuca Mountains of southern Arizona. The name memorabilis ( Oberholser, 1921 ) applied to the breeding birds of the Southern Rockies, etc., is not recognizable because of broad intergradation in wing length and plumage characters with northwestern populations. However, infra-subspecific segregation of long- and short-winged extremes of the interior and the Northwest Coast populations, respectively, may be useful and is provided for in the key. KEY This key is intended both as a summary of taxonomically useful geographic variation and as a synopsis of populations, named and otherwise, which can be reliably segregated on such bases. Segregates which are worthy of formal John P. Hubbard VARIATION IN DENDROICA CORONATA 367 subspecific recognition are identified only by name, whereas infra-subspecific ones are identified by breeding range with names that have been applied to them in quotes. The intergrade populations which bridge coronata and auduboni and those which bridge auduboni {^dnemorabilis” ) and nigrifrons are not included. Characters given here yield identifications which have a 95 per cent or better probability of accuracy. 1. Light brown to white post-ocular line present in winter and breeding plumages; throat light brown to white in all plumages; white in outer 2 to 3 pairs of rectrices in most females and first-year males and in outer 3 to 4 in most adult males. coronata a. Minimum wing lengths: females — 73.5 mm, first-year males — 75.5 mm, adult males — 78.0mm breeding populations of Alaska, Yukon, MacKenzie Delta, northwestern British Columbia (“/jooueri”) • b. Maximum wing lengths: female — 69.0 mm, first-year males — 72.0 mm, adult males — 74.0 mm; includes all males with solidly black breasts in breeding plumage breeding populations from MacKenzie and northeastern British Columbia eastward to the Atlantic Coast. 1. Post-ocular line absent in winter and breeding plumage; throat yellow in breeding plumage and yellowish (at least in malar region) in winter plumage, except in some first-year females and (rarely) males which have none; white in the outer 4 pairs of rectrices in most females and first-year males and in outer 5 in most adult males (if not wing exceeds 74.5 mm in females, 78.5 mm in first-year males, 80.5 mm in adult males). 2 2. Breeding-plumaged male gray above lightly streaked with black, breast streaked to solidly black and sides streaked with black; female grayish to light brown above, lightly streaked with blackish on upperparts, breast, and sides. Winter-plumaged adult male gray above streaked with black and variably washed with light brown or light rufous brown, breast spotted or mottled with black and washed with buff; first-year male similar but more extensively brown (less grayish) above and with blackish on breast as streaks; females similar to last but streaking paler and much more diffuse auduboni a. Maximum wing length: females — 71.0 mm, first-year males — 74.0 mm, adult males — 77.0 mm breeding populations of costal areas of British Columbia, Washington, and Oregon. b. Minimum wing lengths: females — 76.5 mm, first-year males — 78.5 mm, adult males — 81.0 mm breeding populations of the Rockies, Black Hills, Great Basin, Sierra Nevada, and southwestern United States C'^niemorabiUs") . 2. Breeding-plumaged males more extensively black above and below; females darker above and with heavier streaking above and below. Winter-plumaged males more extensively gray or black above and more extensively black below; first-year males and females darker brown above and with heavier streaking above and below than auduboni — — - — 3 3. Breeding-plumaged males gray above with heavy hlack streaking, sides and front of head washed with blackish, breast, sides, and posterior abdomen solidly hlack, post-auricular and post-coronal patches grayish white; female sooty to moderately THE WILSON BULLETIN December 1970 Vol. 82, No. 4 368 dark brown above with moderate streaking on the crown. Winter-plumaged adult male extensively gray above with considerable black streaking and variable (but usually limited) wash of dark rufescent brown, below mottled or solidly black on the breast, sides, and posterior abdomen, washed with buff; first-year male similar but less grayish, more extensively brown above and black of underparts usually as spotting; female similar to last but not as dark brown above with lighter streaking and with blackish of underparts as streaks nigrijrons 3. Breeding-plumaged males solidly black above or with limited gray streaking or mottling, breast and sides solidly black but posterior abdomen white, post- auricular and post-coronal patches white; female browner less sooty above with heavier streaking on the occiput. Winter-plumaged adult male identical to breed- ing male, lacking browns or buff in plumage; first-year male grayer, less brownish above with more extensive streaking than nigrifrons; female is richer, less sooty above with heavier streaking on the occiput than nigrifrons goldmani SUMMARY Geographic variation in plumage and measurements is discussed in the Dendroica coronata (L.) complex, consisting of two semispecies coronata and auduboni Townsend, particularly with reference to features which bear on segregation of populations, either as formal subspecies or as “infra-subspecies.” The latter are populations that have some distinctive character (s) by which individuals can be identified, but which lack sufficient separability to warrant formal recognition. In the coronata group only the nominate race is formally recognized, although breeding populations of northwestern North America {‘^hooveri” McGregor) are infra-subspecifically separable from more easterly ones on the basis of extremes in wing length, i.e., long versus short. In the auduboni group three subspecies are recognized: auduboni, nigrifrons Brewster, and goldmani Nelson. Within the first, infra-subspecific segregation of breeding populations in the coastal northwest from those of the interior {“memorabilis’’ Oberholser), is possible on the basis of extremes of wing length, i.e., short versus long. Because of the largely clinal or mosaic nature of mensural variation, the characterization of the four accepted sub- species in this complex is basically on plumage characters. Plumage characters also show clinal gradation but discontinuities or steps in the dines are such that formal naming of subspecies is justifiable. The provision for the identification of infra-subspecies is to allow study of dispersal and other features in populations which have identifiable extremes but which are not sufficiently separable to warrant formal, subspecific recogni- tion. ACKNOWLEDGMENTS I am most appreciative to D. Boag, J. S. Farris, N. L. Ford, M. Foster, E. T. Hooper. S. D. MacDonald, Rogers McVaugh, G. G. Musser, H. B. Tordoff, and particularly to Robert W. Storer for their contributions to this study. I am grateful for the privilege of using specimens from the following collections: American Museum of Natural History, David Boag collection, British Museum (Natural History), California Academy of .Science, Carnegie Museum, Chicago Natural History Museum, Denver Natural History Museum, Los Angeles County Museum, Louisiana State University, Museum of Compara- tive Zoology, Museum of Vertebrate Zoology, National Museum of Canada, New Mexico .State University, Occidental College (Moore collection), Ohio State University, Olin S. Pettingill collection. Provincial Museum of British Columbia, Royal Ontario Museum, John P. Hubbard VARIATION IN DENDROICA CORONATA 369 Ray Salt collection, San Diego County Museum, George M. Sutton collection, United States National Museum, and the universities of Alberta, Arizona, California at Los Angeles (Dickey collection), Kansas, Michigan, New Mexico, Oregon, Utah, and Wash- ington. Special thanks go to the late A. H. Miller who kindly allowed me to use the extensive material he had collected for a planned revision of the auduhoni group. Much appreciated financial support was received from the Chapman Fund and from the National Science Foundation. My collecting was authorized through the kindness of federal and local officials in the Dominion of Canada, the Republic of Mexico, and the United States of America. Final thanks go to my wife, Claudia, whose assistance has been an important element in the completion of this work. LITERATURE CITED Brew^ster, W. 1889. Descriptions of supposed new birds from western North America and Mexico. Auk, 6:86-98. Godfrey, W. E. 1951. Comments of the races of the Myrtle Warbler. Canadian Field- Naturalist, 65:166-167. Hubbard, J. P. 1967. A systematic study of the Dendroica coronata complex. Unpubl. Ph.D. thesis, Univ. Michigan, Ann Arbor. Hubbard, J. P. 1969. The relationships and evolution of the Dendroica coronata com- plex. Auk, 86:393-432. Mayr, E., E. G. Linsley, and R. L. Usinger. 1953. Methods and principles of sys- tematic zoology. McGraw-Hill, New York. McGregor, R. C. 1899. The Myrtle Warbler in California and a description of a new race. Cooper Ornithol. Soc. Bull., 1:31-33. Nelson, E. W. 1897. Preliminary description of new birds from Mexico and Guatemala in the collection of the United States Department of Agriculture. Auk, 14:42-76. Oberiiolser, H. C. 1918. Notes on North American birds, VI. Auk, 35:463-467. Oberiiolser, H. C. 1921. A revision of the races of Dendroica auduboni. Ohio J. Sci., 21:240-248. Steel, G. D. and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw- Hill, New York. Townsend, J. K. 1837. Description of twelve new species of birds, chiefly from the vicinity of the Columbia River. Philadelphia Acad. Nat. Sci. Jour., 7:187-193. DEPARTMENT OF BIOLOGY, VIRGINIA POLYTECHNIC INSTITUTE, AND ROCKBRIDGE ALUM SPRINGS BIOLOGICAL STATION, GOSHEN, VIRGINIA 24439, ORIGINALLY RECEIVED 17 MARCH 1969. NESTING BIRD ECOLOGY OE FOUR PLANT COMMUNITIES IN THE MISSOURI RIVER BREAKS, MONTANA Kenneth C. Walcheck The Missouri River “Breaks” is a name that has been applied to that section of the immediate Missouri River Valley which stretches ap- proximately 180 miles between Fort Benton and the Fort Peck Reservoir, Montana. This stretch of the river is divided by topographic features into three separate units — The Fort Benton-Virgelle unit, the White Rocks- Badlands unit, and the Fort Peck Game Range. This region is of particular interest since it represents a stretch of the river that retains much of the same aspect as when first seen by Lewis and Clark, fur trappers, and steam- boat passengers. Because of the tremendous size of the “breaks” area, my studies were concentrated in that area known as the White Rocks-Badlands unit which originates approximately 42 river miles downstream from Fort Benton in north-central Montana. This area was selected because of its limited ac- cessibility, “pristine” wilderness aspect, because there have been no published avifaunal investigations for this specific area, and lastly, because the U.S. Army Corps of Engineers has proposed several dam sites for water-resource development. Inundation would destroy the most unique geological, historical, paleontological, and biological features found in this stretch of the river. The study area consisted of a straight-line distance of about 33 miles (45 river miles ) . The purpose of this paper is to describe the breeding bird popu- lations of the major habitats and to establish certain ecological relationships between these populations and their communities. Preliminary observations were made in 1967 with quantitative data obtained during the summer of 1968. METHODS Study areas were selected in each vegetation type that were typical of that type and that had a minimum amount of disturbance. Study areas in the greasewood-sage- hrush shrubland, sagebrush grassland, and pine-juniper woodland were 40 acres in size with dimensions of 660 X 2640 feet. Each area was censused at 220 feet intervals. Because of the strip-like nature of these areas, one source of error present in mapping territories is that some territories included some area beyond the boundaries of the study zone. Care was taken, where possible, to select areas with physiographic barriers and distinct plant communities isolating such areas, thereby reducing the error. Located on an abandoned meander, the study area in the cottonwood forest consisted of an area 17..5 acres in size and was censused at 150 feet intervals. Breeding bird populations were studied with the aid of composite census maps similar to those described by Kendeigh (1944). Descriptive data on such maps in- cluded birds seen and singing males, location of active nests, eggs per nest, young out 370 Kenneth C. W alcheck NESTING BIRD ECOLOGY 371 of the nest, and behavioral activities related to nesting. Long poles, to lap silver sage- brush {Artemisia cana) plants, aided in flushing nesting birds during each census in the sagebrush-grassland community. A Labrador dog was also used in this type for flushing King-necked Pheasants.^ Census periods and times for each study plot were as follows: cottonwood forest (8 trips, 2-8 June; census time, 06:00-09:30), sagebrush-grassland (6 trips, 9-14 June; 06:00-08:30), greasewood-sagebrush shrubland (6 trips, 16-21 June; 06:00-09:00), pine- juniper woodland (6 trips, 25-30 June; 06:00-10:00). Visits to the plots for other purposes supplied confirmatory data beyond the time spent in formal censusing. The method of vegetation analysis was a modification of this method of Dauhenmire (1959), whereby 2x5 dm plots were systematically placed within a relatively ho- mogenous and undisturbed portion of each habitat studied. Measurements were also taken at nest sites for certain avian species to attempt to ascertain nesting requirements, whereby 20 X 50 foot sample units, each containing 20 systematically arranged 2X5 dm plots enclosed separate nest sites. The per cent canopy coverage of each taxon ( per cent of area covered by foliage), the average frequency (percentage occurrence among plots), and percentage of bare ground, rock and lichens were recorded for each plot. Canopy coverage classes were: 1 = 0-5 per cent; class 2 = 5-25 per cent; class 3 =25-50 per cent; class 4 = 50-75 per cent; class 5 = 75-95 per cent; and class 6 = 95-100 per cent. The midpoint of each class was the value used in data tabulations. Comparative data for these types are presented in Table 1. The botanical nomenclature follows that of Booth (1950) and Booth and Wright (1959). VEGETATION The study area lies in the Prairie Biome, more specifically, the Mixed Prairie which is composed predominantly of mid and short grasses. Vegetation in the White Rocks- Ifadlands unit is varied due to ridges, sharply cut coulees, and creek bottoms. The major l)lant communities in the study area are as follows: Greaseivood-Sagebrush Shrubland. — Where clay soils containing considerable amounts of sodium occur, the vegetation is characteristically sparse and dominated by grease- wood { Sarcobatus vermicu/atus) — a point established by Mackie (1965). Distribution of greasewood, big sagebrush (Artemisia tridentata) , and silver sagebrush ranges from sparse to moderate along Missouri River bottomlands, coulee-bottom benches, small alluvial fans, and hills with exposed bentonite beds. Principal forbs include wooly plantain (Plantago purshii), western stick tight (Lappula redowskii) , littlepod false flax (Camelina microcarpa) , and plains prickly pear (Opuntia polycantha) . Dominant grasses include downy chess hrome (Bromus tectorum) , western wheatgrass ( Agropyron smithii). and desert saltgrass (Distichlis stricta) . Sagebrush Grassland. — Relatively dense stands of silver sagebrush ranging in height from two to six feet occur extensively along the Missouri River bottom lands and coulee bottoms having intermittent stream flow. Western wheatgrass, the former dominant in this type, has been greatly replaced by the invader downy chess hrome. The distribution and fluctuation of these two grasses is related to livestock distribution and intensity of grazing. In areas where extensive grazing has occurred in silver sagebrush, subsequent erosion has produced hard, clay-pan soils, with reduced vegetative cover. Meadow barley (Hordeum brachyantherum) , wooly plantain, and littlepod false flax are common in such areas. The canopy coverage for silver sagebrush is more extensive and the total forb and grass coverage is greater than that of the greasewood-sagebrush shrubland. ' Scientific names of birds are given in Table 2. 372 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 1 Per cent Canopy Coverage (%) and Frequency of Occurrence (f) of Vegetation FOR Communities as Determined by Measurements Within 260 Plots EACH 2 X 5 DM in Size (Plants having a canopy coverage of less than 1 per cent are not included.) Greasewood- S agebrush Shrubland Sagebrush Grassland Pine-Juniper Woodland Gottonwood Forest Grasses and grassdike plants % / % / % / % / Agropyron smithii 3 30 26 95 3 20 Agropyrori spicatum 12 41 2 10 Bouteloua gracilis 3 14 Bronius tectoriim 14 28 12 53 Calamovil fa longifolia 5 21 Carex spp. 9 32 Distichlis stricta 2 12 Elymus canadensis 2 3 Festuca octiflora 1 30 Hordeum brack yantherum 8 48 Koeleria cristata 4 36 2 45 8 41 Poa spp. 1 40 2 3 Stipa comata 1 15 2 13 Forhs Camelina microcarpa 2 47 5 65 2 24 Cerastium arvensis 2 11 Lappula redowskii 4 22 Lepidiuni virginicum 2 50 Liniuni rigid urn 2 12 Opnntia poly can tha 6 25 3 8 Phlox hoodii 2 19 Plantago purshii 4 42 PI an ta go spp. 4 28 Selaginella densa 1 15 Sisymbrium incisum 1 18 Smilacina racemosa 1 13 Vida americana 1 15 Shruhs Artemisia can a 53 80 Artemisia tridentata 9 30 9 19 Fraxinus pen nsyl ivanica (seedlings) 7 53 Rhus trilobata 9 11 Rosa nutkana 34 65 Sarcobatus vermiculatus 8 35 Symphoricarpos occidental is 28 88 Kcnnetli C. alcheck NESTING BIRD ECOLOGY 0^‘> o /o Table 1 ( ! Gontinued ) Greasewood- Sagebrush Shnibland Sagebrusli Grassland Pine- Juniper Woodland Gottonwood Forest I'rees Pinus flexilis Juniperus scopuloruni Juniperus communis Populus sargentii Fraxinus pennsylvanica Acer negundo Rocks 1 18 5 41 Lichens 5 72 1 13 1 25 Bare Ground 20 88 3 25 28 79 Pine-Juniper Woodland. — This community occurs extensively on slight to moderately steep slopes in those areas where Eagle Sandstone is exposed. Stands of limher pine iPinus flexilis) and Rocky Mountain juniper (Juniperus scopuloruni) are typically scattered in these areas. The understory shrulj layer is composed of common juniper (Juniperus communis) and skunkbush sumac (Rhus trilobata) . Principle forhs and grasses include hoods phlox (Phlox hoodii) , Carex spp., and junegrass {Koeleria cristata) . Small hills with moderately cut drainageways separating such stands are common. Such areas support a variable vegetation comprised of dense growths of skunkbush and com- mon juniper in the drainageways, and big sagebrush, plains prickly pear, yucca {Yucca g/auca) and needle and thread (Stipa comata) on the periphery. Cottonwood Forest. — The cottonwood habitat, dominated by plains cottonwood (Populus sargentii) , is found along Missouri River bottom lands and on numerous islands in this reach of the river. The larger groves show three distinct strata. Cottonwood comprises the upper stratum ( 18-19 m) ; the second stratum consists of green ash (Fraxinus pennsylvanica) (2-11 m), and scattered box elder (Acer negundo) ; the third stratum consists of moderate to heavy thickets of western snowberiy ( Symphoricarpos occidentalis) and nootka rose (Rosa nutkana) . Litter accumulation is quite heavy in the larger cottonwood groves resulting in limited growth of forhs and grasses. The most common forb is American vetch (Vicia americana) and the most common grass is hlue- hunch wheatgrass ( Agropyron spicatum) . Heavy silting from flooding has undoubtedly influenced the species composition and vegetation grouping patterns in those areas sub- jected to a high frequency of flooding. Other vegetation types of lesser importance found in the study area hut not quantita- tively analyzed include small islands covered with Salix spp. and low herbaceous growth; numerous long, open canyons with dissected drainageways that support a variable growth in vegetation; and limited stands of Douglas fir ( Pseudotsuga menziesii) associated with limljer pine. RESULTS Greaseivood-Sagebrush Shrubland. — Lark Sparrows and Western Meadow- larks were the two most abundant species found in this habitat (Table 2). 374 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 2 Nesting Birds (pairs per 100 acres) found in Four Plant Communities of the White Rocks-Badlands Unit Greasewood- Pine- Type of habitat Sagebrush Sagebrush Juniper Cottonwood Shrubland Grassland Woodland Forest No. of acres 40 40 40 17.5 Species P'erruginous Hawk ( Buteo re gal is ) 6 Pigeon Hawk (Falco columbarius) 6 Sparrow Hawk ^ Falco sparverius) 6 Ring-necked Pheasant i Phasianus colchicus) 5 Mourning Dove ( Zenaidura macroura) b 5 50 13 Black-billed Cuckoo (Coccyzus erythropthalmus) Great Horned Owl i Bilbo virginianus) Saw-whet Owl (Aegolius acadicus) Common Nighthawk (Chordeiles minor) Red-shafted Flicker ( Colaptes cafer) Downy Woodpecker { Dendrocopos pubescens) Eastern Kingbird (Tyrannus tyranniis) Western Kingbird (Tyrannus verticalis) Least Flycatcher i Empidonax minimus) Western Wood Pewee (Conlopus sordidulus) Cliff Swallow ( Petrochelidon pyrrhonota) Black-billed Magpie (f*ica pica) Black-capped Chickadee (Parus atricapillus) a 0 3 6 13 13 3 13 13 a 6 13 Kenneth C. Walclieck NESTING BIRD ECOLOGY 375 Table 2 ( Continued ) Greasewood- Pine- Sagebiaish Sagebrush Juniirer Cottonwood Tyi^e of habitat Shrubland Grassland Woodland Forest No. of acres 40 40 40 17.5 5 45 5 House Wren {Troglodytes aedon) Rock Wren (Salpinctes obsoletus) Catbird { Dumetella carolinensis) Brown Thrasher ( Toxostoma rujum) Robin {Turdus migratorius) Swainson’s Thrush { H ylocichla ustulata) Veery i H ylocichla fuscescens) Cedar Waxwing ( Bombycilla cedrorum ) Loggerhead Shrike iLanius ludovicianus) Starling iSturnus vulgaris) Red-eyed Vireo ( Vireo olivaceus) Yellow Warbler i Dendroica petechia) Yellowthroat i Geothlypis trichas) American Redstart (Setophaga ruticilla) Western Meadowlark { Sturnella neglecla) 25 Baltimore Oriole (Icterus galbula) Bullock’s Oriole (Icterus bullockii) American Goldfinch (Spinus tristis) Rufous-sided Towhee (Pipilo erythrophthalmus) 13 8 15 26 13 a 13 5 19 19 52 13 19 10 13 6 13 6 8 13 376 THE WILSON BULLETIN Decenilier 1970 Vol. 82, No. 4 Table 2 ( Continued ) Type of habitat Greasewood- Sagebrush Shrubland Sagebrush Grassland Pine- Juniper Woodland Gottonwood Forest No. of acres 40 40 40 17.5 Lark Bunting ( Calamospiza melanocorys) Grasshopper Sparrow ( Ammo d ramus savannarum ) Vesper Sparrow 5 6 i Pooecetes gramiiieus) 5 Lark Sparrow i Choiidestes grammacus) Chipping Sparrow 30 5 18 iSpizella passerina) Brewer’s Sparrow 13 (Spizella breweri) 5 48 Total pairs per 100 acres 65 78 146 390 “ Indicates species present on study area but density low or difficult to assess. Indicates species which nested outside the study irlot in this habitat and sirecies frequently observed but not definitely known to nest in the study plot. These species comprised 46 per cent, and 39 per cent, respectively, of the total breeding population. Although the presence of greasewood and big sagebrush appears to be a nesting requirement for the Lark Sparrow, nest data indicate more specific nesting requirements with regard to big sagebrush. Of the eight Lark Sparrow nests located, seven were found on the ground directly under big sagebrush, but only one under greasewood. Vegetative measurements taken at four separate nests, based on four 20 X 50 sample units showed greasewood with a canopy coverage averaging 14 per cent and life form measurements of 0.37 m (height of shrub) X 0.6 m (width of crown). Big sagebrush had similar life form measurements of 0.54 X 0.62 m and a canopy coverage averaging 15.6 per cent. Examination of Table 1 shows that the average frequency ratings for both shrubs were quite similar. A comparison of the life forms for big sagebrush and greasewood shows that the former has many more overhanging branches that could be used for nest concealment and protection. The lowermost branches of greasewood, in contrast, are more upright thereby providing less overhang and coverage. Because the lowermost branches of greasewood are not positioned as well as those of big sagebrush to intercept rainfall, the soil tends to be more com- pact forming a “hardpan” layer under the plants. The surface soil texture Kenneth C. Walcheck NESTING BIRD ECOLOGY 377 under big sagebrush is more granular, has a higher percentage of litter, and lacks this hardpan consistency. It seems quite probable that nest depressions could he excavated with greater ease in such a substrate. The difference in soil porosity for these two shrubs strongly suggests that porosity may he an important factor in nest selection. The Western Meadowlark was found in areas having more herbaceous and grass cover and with more widely dispersed shrubs than were present in the habitat of the Lark Sparrow. Each of the two meadowlark nests located was built adjacent to the paddles of prickly pear cactus. Two meadowlark nests found in the pine- juniper woodland were similarly located in prickly pear cactus. Cameron ( 1907 ) also reported a nesting bird in a cactus patch for eastern Montana. Sagebrush-Grassland. — The most abundant species. Brewer’s Sparrow, comprised 61 per cent of the total breeding population for this habitat. After charting the locations of 15 active Brewer’s Sparrow nests on the composite census maps, it was evident that this species preferred silver sage- brush areas having a canopy coverage of around 50 per cent for nest sites. Quantitative measurements, based on 80 Daubenmire plots, showed sub- stantial differences in the utilization of sagebrush by this species for nesting purposes. Most of the nests, eleven or 73 per cent, were found in silver sagebrush areas having a canopy coverage averaging 53 per cent. Shrubs averaged one meter high by 1.2 meters wide. Low density sagebrush areas in which one nest was found included shrubs having a canopy coverage of 24 per cent and physical measurements of 0.4 X 0.56 m. Three nests ( 20 per cent ) were found in dense sagebrush areas averaging 1.4 X 1.6 m and had a canopy coverage of 81 per cent. The physiognomy or structure of the vegetation in this habitat appears to be quite important in the selection of nest sites thereby influencing the distribution of birds. Feist ( 1968) in his study of five 40-acre plots of big sagebrush-grassland in central Montana, maintained that the Brewer’s Sparrow preferred dense sagebrush areas for nest sites with a canopy coverage averaging 31 per cent. While there is some overlap in regard to the height and canopy coverage of silver sagebrush utilized by this species, it is my belief that dense silver sagebrush areas are used less frequently in comparison with those of l)ig sagebrush. Pine-Juniper Woodland. — Scattered stands of limber pine and juniper separated by open herbaceous-grassy areas with associated dissected drain- ageways containing numerous brush pockets, provided a diversified ecological community for nesting birds. Mourning Doves, the most abundant nesting bird for this type, were dispersed throughout the study area and nests were located in all cover types. 378 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 3 CoMPAiusoN OF Per Cent Canopy Coverage and Ground Cover Lark Sparrow Nesting Sites in the Greasewood-Sagebrusii Pine-Juniper Woodland Communities Characteristics at Shrubland and Canopy coverage and ground Greasewood-Sagebrush Pine-luniper cover characteristics Shrubland Woodland Shrubs 15 18 Forbs and Grasses 45 44 Lichens 7 2 Rock 1 4 Bare ground 31 36 The ecological adaptability of the Mourning Dove in its ability to nest in conifers, deciduous trees, and a wide variety of shrubs as well as on the ground is well known (Bent, 1932). The dove selected a wide variety of nest sites on the study area. Of the 17 nests located, eight were located on horizontal branches of conifers with limber pine being the preferred species. Although Rocky Mountain juniper was common in the understory of limber pine, it showed a low frequency for nest sites. It was my impression that juniper was not selected for nest sites because of the typical dense and upright branches which result in a poor structural platform. The lowermost branches of limber pine, in contrast, are more horizontal and open, thereby providing more suitable nesting platforms. A horizontal branch appears to be the essential requisite for the nest platform in conifers. Hanson and Kossack ( 1963 ) found in their Illinois study of doves that blue spruce (Picea pungens) was preferred over four other conifers, including pine, because of its stiff, horizontal branches and needles which provided secure nesting platforms. Hardy (1945) found that the Mourning Dove in a Pihon- Juniper vegeta- tion type preferred juniper to pinon pine (Pinus edulis) because the former has larger and more horizontal branches. Other species showing a nesting preference for conifers were the Chipping Sparrow, Robin, and Loggerhead Shrike. Lour of the five Robin nests located were in limber pine and they averaged 3.9 m off the ground. Although only one Chipping Sparrow nest was found, numerous old nests located, all in juniper, suggested that this was the preferred nesting site. The third most abundant species, the Lark Sparrow, preferred big sage- brush areas similar to those in the greasewood-sagehrush habitat. Vegetative measurements taken at one nest site, based on 20 Daubenmire plots, showed an average total canopy coverage of 64 per cent. Comparison of these data with that of the greasewood-sagehrush habitat shows a remarkable similarity in nesting niches (Table 3). Kennctli C. Walcheck NESTING BIRD ECOLOGY 379 Brushy, dissected drainagevvays, containing dense pockets of skunkbush sumac and common juniper provided nesting sites for the Brown Thrasher and Rufous-sided Towhee. Although such areas were not abundant, they were of importance to such species. Cottonwood Forest. — This community supported the largest number and the greatest variety of species. Thirty species of birds utilized this type for nesting. The cottonwood community offers more opportunities for ecological specialization than the habitats found in the other communities examined. Since this community shows three well-defined strata, and since there were substantial differences in the utilization of each stratum for nesting, the birds for each will be described. While there was some overlap in nesting niches among the various strata, 12 of the total breeding species nested in the upper cottonwood stratum ( House Wren, Red-shafted Elicker, Bullock’s Oriole, Downy Woodpecker, Western Kingbird, Baltimore Oriole, Sparrow Hawk, Black-billed Magpie, Great Horned Owl, Ferruginous Hawk, Pigeon Hawk, and Starling). About one-third of these were hole nesters. High intensity winds frequently occur in the “Breaks” area producing a large number of cottonwood culls which make such trees suitable for excavation. The middle stratum (green ash with scattered box elder) had the lowest number of nesting birds. Eight species, of which the Robin was the most common, nested in this stratum. This stratum has fewer nesting niches in comparison with the upper stratum. For example, the number of culls for excavation were certainly fewer, thereby limiting hole-nesting species. The lower stratum (rose and snowberry) provided nesting sites for ten species. Vegetation measurements for this stratum showed a total average canopy coverage of 74 per cent. Shrubs (rose and snowberry) averaged 62 ]>er cent with forbs and grasses averaging four per cent. Although snow- berry had an average frequency rating similar to that of rose, no nests were found in this shrub. A comparison of life forms shows snowberry as a shrub with numerous slender, drooping branches; rose in contrast, is a more erect shrub having stouter branches armed with numerous spines thereby providing more suitable nesting crotches. This stratum provided the least variety of nesting niches. Typical nesting birds utilizing this stratum were the Yellow Warbler, American Goldfinch, Swainson’s Thrush, Gatbird, and Veery. Forest edge species (Rufous-sided Towhee, Yellowthroat, Grasshopper Sparrow, Eastern Kingbird) utilizing rose thickets bordering and encroach- ing into the sagebrush-grassland community seldom penetrated the cotton- wood interior for more than 10—20 feet. 380 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 DISCUSSION The general pattern of the utilization by birds of each habitat for nesting reflects the basic physiognomy or structure of the vegetation. Although there is a certain amount of overlap in plant species and configuration used for nesting, data from this study show that some bird species show a very close adherence to a specific life form of vegetation present, while others are more flexible in using the overall habitat. The Lark Sparrow, for example, appears partial to nesting under big sagebrush while the Mourning Dove is quite adaptable in being able to use a variety of vegetation for nest sites. The greasewood-sagebrush community is the poorest in species composition and relative density. The density for the five breeding species averaged 65 pairs per 100 acres. The implication is that a low density and productivity of vegetation allow for a low diversity and density of breeding birds. That this suggestion is not necessarily correct is suggested by the data presented earlier in which although big sagebrush and greasewood have similar life forms and frequency ratings, the more granular type soil found under big sagebrush appears to be an important factor in determining Lark Sparrow densities. The sagebrush-grassland community supported six species with a total nesting density of 78 nesting pairs per 100 acres. As pointed out above, the general pattern of distribution of Brewer’s Sparrows in this habitat was a concentration in those areas with shrubs having a canopy coverage averaging 50 per cent. It is possible that shrubs found in such areas may provide more suitable nest sites with overhanging branches that serve to conceal and protect the nest; or perhaps the foliage volume for such shrubs plays an important factor in limiting densities. It is also possible that a difference in the nesting density of Brewer’s Sparrow is not under sole control of differences in shrub density and canopy coverage. The pine-juniper woodland provided a diversified ecological community for nesting birds supporting 14 species and 146 pairs of nesting birds per 100 acres. The high density of Mourning Doves in this habitat is partly explained by the versatility of the species in being able to use a heterogenous mixture of plant life forms for nesting. Examination of Table 2 shows that the dove was the only species having the ecological adaptability to nest in all of the habitats studied, therefore having the greatest density of breeding birds for the entire study area. The multi-storied vegetation structure of the cottonwood forest supports the greatest total biomass and contains the largest population of nesting birds (390 pairs per 100 acres) and the greatest number of species (30). Thus, as a natural habitat, the cottonwood forest can be shown to offer more ■opportunities for ecological specialization than the other habitats. Kenneth C. \^'alcheck NESTING BIRD ECOLOGY 9 0 1 oo L The information summarized in Table 2 is of value in the sense that it presents an instantaneous description of the four avian communities, but it is incomplete. The reasons for this are: (1) Breeding bird measurements were taken during only a part of the breeding season so the true population might vary from the density figures given. ( 2 ) It is not realistic to suggest that the density of nesting pairs of birds per 100 acres for the hawks, owls, kingbirds, and doves in the cottonwood forest is correct. This habitat served primarily to supply nesting sites for these species, and because of the vari- ability of neighboring habitats, it is difficult to make meaningful population adjustments for them. (3) As Brewer (1967) points out, bird populations for a given habitat are a product of many factors, including geographical location of the plant community, geographical ranges of species able to use the habitat, and structural features of the vegetation. Another prime con- sideration is that of habitat change. There is an apparent difference in relative densities in the study area when comparing bird populations of the same community from one locality to another because of livestock dis- turbances. I have no quantitative data concerning the interrelationships that exist between livestock and vegetation in the White Rocks-Badlands unit. My observations indicate noticeable differences. SUMMARY Intensive studies of the nesting birds in four plant communities representative of the White Rocks-Bandlands unit of the Missouri River “Breaks,” Montana were conducted during the summer of 1967 and 1968. The greasewood-sagehrush shrubland has the fewest species and lowest relative density of the four communities. Density for all breeding species averaged 65 pairs per 100 acres. The Lark SpaiTOw and the Western Meadowlark were numerically the most important species. Although life form measurements and frequency ratings for big sagebrush and greasewood are similar in this habitat, a more granular soil under big sagebrush appears to he a nesting requirement for tlie Lark Sparrow. The sagebrush-grassland community supported six species and 78 pairs per 100 acres. The Brewer’s Sparrow was by far the most abundant species. The greatest density of nesting Brewer’s Sparrows was found in silver sagebrush areas having a canopy coverage of around 50 per cent. The pine-juniper woodland provided a diversified ecological community for nesting- birds and supported about 146 pairs per 100 acres. Tlie Mourning Dove was numerically the most important and was the only species having the ecological adaptability to nest in all of the major habitats found in the study area. The cottonwood community supported the largest population of nesting birds (390 pairs per 100 acres) and the greatest number of species (30). This community provided more opportunities for ecological specialization and nesting sites than the habitats in the other communities because of its multi-storied vegetation and greater total biomass. ACKNOWLEDGMENTS The author would like to thank Douglas .lames, .John Weigand, and Steve Bayless who made many useful criticisms of and improvements in the manuscript; Allen Dumas, THE WILSON BULLETIN December 1970 Vol. 82, No. -1 O < > O ' )Z oo^ for assistance with all phases of field work; and Lou Hagener, for his help in plant taxonomy. This study was partially supported by a research grant from the Research Corporation, Burlingame, California. LITERATURE CITED Bent, A. C. 1932. Life histories of North American gallinaceous birds. U. S. Natl. -Mus. Bull., 162. Booth, W. E. 1950. Flora of Montana, part 1, conifers and monocots. Research Foundation at Montana State College, Bozeman, Montana. Booth, W. E. and J. C. Wright. 1959. Flora of Montana, part 2, dicotyledons. Montana State College, Bozeman, Montana. Brewer, R. 1%7. Bird populations of bogs. Wilson Bull., 79:371-396. Cameron, E. S. 1907. The birds of Custer and Dawson Counties, Montana. Auk, 24: 389-406. Daubenmire, R. 1959. A canopy-coverage method of vegetational analysis. Northwest Sci., 33:43-64. Feist, F. G. 1968. Breeding bird populations in relation to proposed sagebrush control in central Montana. Unpubl. thesis ( M. S.) Alontana State University. Hanson, C. H. and C. W. Kossack. 1963. The Mourning Dove in Illinois. Technical Bulletin No. 2. Southern Illinois Univ. Press, Carbondale, 111. Hardy, R. 1945. Breeding birds of the pigmy conifers. Auk, 62:523-543. Kendeigh, S. C. 1944. Measurement of bird populations. Ecol. Monogr., 14:67-106. Mackie, R. J. 1965. Range ecology and relations of mule deer, elk and cattle in the Missouri River Breaks, Montana. Unpubl. thesis (Ph.D.), Montana State University. DEPARTMENT OF BIOLOGY, NORTHERN MONTANA COLLEGE, HAVRE, MONTANA, 29 AUGUST 1969. (originally received 27 February 1969.) NOTICL Members who know students that are interested in ornithology now should send nomi- nations to the Student Membership Committee addressed to Douglas James, Department of Zoology, University of Arkansas, Fayetteville, Arkansas 72701. The nominees will be invited by the committee to apply for membership in the Wilson Ornithological Society. OLDSQUAWS NESTING IN ASSOCIATION WITH ARCTIC TERNS AT CHURCHILL, MANITOBA Roger M. Evans The tendency for the Oldsquaw iClangula hyemalis) to nest in close association with the Arctic Tern {Sterna paradisaea) has been noted in several geographic regions, including Alaska (Bailey, 1925, 1943), Southampton Island (Sutton, 1932), Greenland (Salomonsen, in Larson, 1960), and Spitsbergen (Lovenskiold, 1954; Burton and Thurston, 1959). Taverner and Sutton (1934) reported both species as common breeders along the west coast of Hudson Bay, near Churchill, Manitoba, but did not refer explicitly to association of nests of the two species. That such associations do occur in this region, however, is indicated by the observations of Twomey {in Taverner and Sutton, 1934) that populations of both species nested on a single small offshore island. Hawksley (1957:66) states that “the Old-squaw is commonly found nesting with Arctic Terns in North America,” and implies that such associations occur at Churchill, but does not indicate the locations or extent of the association in this region. Evidence that close as- sociations between nests of Oldsquaw and Arctic Tern are common on the mainland at Churchill, and particularly on small islands in fresh-water ponds, is presented below. Larson (1960) has suggested that nest associations such as those mentioned above are commensal, the Oldsquaw deriving a degree of protection from potential nest predators as a result of the well-developed nest defense be- havior of the Arctic Tern. The interpretation that protection from nest predators is derived by the Oldsquaw or other species, notably the eider iSomateria) and brant [Bran la bernicla; B. nigricans) when they nest in association with Arctic Terns, has also been advanced by several other investigators, including Lovenskiold (1954), Gudmundsson (1956), Burton and Thurston (1959) , Hilden (1965) , and Cooch (1967). Koskimies (1957) and Vermeer 11968) have advanced the further hypothesis that imprinting of ducklings to gulls or terns nesting in the same vicinity may constitute the proximate cause of these and other similar associations. The hypothesis that nest associations between Arctic Terns and Oldsquaws are commensal relationships that develop locally as a result of imprinting does not appear to have been subject to rigorous experimental tests. In the absence of such data, extensive documentation of the occurrence or non- occurrence of such nest associations in various local areas, including those where avian nest predators are common as well as those where such predators are rare or absent, would appear to be useful. The following oh- THE WILSON BULLETIN December 1970 Vol. 82, No. i 1 Table 1 Distance between Oldsquaw Nests and Nearest Open Water Distance to water ( meters ) Nest location Number of nests Mean Median Range Mainland beach 3 9.0 9 8-10 Mainland tundra 9 28.6 1 0.2-200 Islands in fresh water 16 2.1 2 0.1-6.7 servations of the nest sites selected by 01dsc|uaws, the extent of their as- sociation with Arctic Terns, and the relationships of these associations to the more common avian predators in the Churchill region are presented here as a contribution towards such documentation. DESCRIPTION OF NEST SITES According to Phillips (1925), “there is nothing characteristic about the (Oldsquaw) nest or its site. It is usually near the water, though sometimes far away from it . . . and is placed under thick bushes . . . when such cover is found.” Oldsquaws may nest as isolated pairs, or “practically in colonies” ( op. cit., p. 362 ) . This description applies with validity to the Oldsquaw nests observed at Churchill, where nests were found in virtually all major terrestrial areas, including (1) mainland beach, (2) mainland tundra, (3) islands in fresh-water ponds, and (4) offshore islands. The present observa- tions, conducted during June and July of 1967 and 1968, were concerned primarily with the first three of these nest habitats; confirmation of the observations cited in Taverner and Sutton (1934) of Oldsquaws nesting on offshore islands was provided by Mr. Carroll Littlefield ( pers. comm. ) , who counted seven Oldsquaw nests on a small island off the coast of Cape Churchill on 27 June 1968. Although the Oldsquaw is said typically to nest along the edges of small fresh-water ponds or on islands in such ponds (Phillips, 1925; Bent, 1925), records of nests placed some distance away from the nearest open water are not uncommon. Bent (1925), for example, cited observations by Hersey of a nest placed 20 feet from the edge of a pond, and a report by Palmer of a nest 40 feet from a fresh-water pond. He further cited Ekblaw that nests are “sometimes in the grass near the pools, but more frequently ... at consider- able distances from any water” (Bent, 1925:38). At Churchill, the dis- tances to the nearest open water were also variable, ranging from as little as 0.1 m to at least 200 m for the 28 nests measured (Table 1). The distance between Oldsquaw nests and the nearest open water at Churchill was found to vary according to the area in which the nests were lloger M. Evans OLDSQUAW-ARCTIC TERN ASSOCIATION 385 Table 2 Distance between Oldsquaw Nests and Nearest Arctic Tern Nest Nest location Number of nests Distance to nearest tern nest ( meters ) Mean Median Range Mainland lieach 3 13 12 10-17 Mainland tundra 5* 72 70 18-178 Islands in fresh water 16 2.3 2 0.8-6 * Does not include three nests located in the vicinity of Arctic Terns but for which distances to tern nests were not determined, and one nest that was not in association with terns. located ( Table 1 ) . Average distances were least on the small islands in fresh-water ponds (average for 16 nests, 2.1 m), somewhat greater along the beach ( average for three nests, 9.0 m ) , and greatest in the mainland tundra (average for nine nests, 28.6 m). The average distance to water for the mainland tundra is skewed due to a number of extreme values well above the median distance of 1 m. Except for these extreme values on the main- land tundra, nest sites tended to he close to the shore for both fresh-water islands (median 2 m) and mainland tundra (median 1 m), and somewhat farther from water for nests located along the beach ( median 9m). These results suggest that Oldsquaws at Churchill exhibit a definite tendency to nest near the edge of water, but not exclusively so. This tendency is necessarily reinforced when small islands no more than a few meters in diameter are selected for nest sites, but may be relaxed when mainland tundra locations are selected. Eor nests located along the beach the minimum distance to water appeared to be set by the maximum extent of wave action at high tide. In each of the three areas described above, Oldsquaws were found nesting in association with Arctic Terns. A similar association was also present on the small offshore island visited by Littlefield (pers. comm.). On islands in fresh-water ponds, Oldsquaw nests were found exclusively on islands that also contained Arctic Terns. In consequence, minimum distances between nests of the two species on these islands were necessarily small ( average for 16 nests, 2.3 m), with none exceeding 6 m (Table 2). In the other areas, and particularly on mainland tundra, distances between Oldsquaw and Arctic Tern nests were greater, ranging up to at least 178 m (Table 2). In addition, one Oldsquaw nest was found on mainland tundra in an area that apparently lacked a local population of breeding terns. This latter finding, coupled with the greater distances between nests of the Oldsquaw and Arctic Tern on the mainland tundra (Table 2), suggests a relaxation in the tendency for association between the two species on mainland tundra compared to islands in fresh-water ponds. OoO THE WILSON BULLETIN December 1970 Vol. 82, No. 4 It should be noted that nest hunting for Oldsquaws was concentrated in areas that contained Arctic Terns, and random sampling of large areas of habitat was not done. The high frequency of association between Arctic Terns and Oldsquaws found at Churchill may therefore be biased upwards, due to an undetermined number of Oldsquaw nests being located well away from areas containing terns. Several considerations suggest, however, that the possibility of such a bias does not negate the conclusion that an associa- tion between the species does in fact occur, especially for those nests located on islands in fresh-water ponds. As indicated above, all 16 Oldsquaw nests found on such islands were in close association with Arctic Terns. While searching for nests in these areas, many islands in addition to those found to contain tern nests were inspected, yet in no instance was an Oldsquaw nest found on an island that lacked terns. Nests located on islands in one small fresh-water pond are illustrative: In 1967, two islands in the pond each had one Oldsquaw nest and one tern nest. In 1968, one of these islands had an Arctic Tern nest and two Oldsquaw nests; the other island contained nests of neither species. Lrom considerations such as these, coupled with the measurements listed in Table 2, it seems reasonable to conclude that a definite positive association between Oldsquaw and Arctic Tern nests was present at Churchill in 1967 and 1968. An exact determination of the frequency of this association on mainland tundra remains lacking, however, pending a more complete and random sampling of the potential nesting habitat. AVIAN PREDATORS At least three potential avian predators of Oldsquaw eggs were present at Churchill: Herring Gull {Larus argentatus) , Parasitic Jaeger [Stercorarius parasiticus), and Common Raven (Corvus corax). Of these species, the Herring Gull was most common; 15 and 22 breeding pairs were found, widely scattered, throughout the study area in 1967 and 1968 respectively. In addition, mixed flocks composed largely of non-breeders of this and other large Larus gulls totalling several hundred in number could be ob- served daily at the local garbage dump located near the middle of the study area. Egg predation of ground-nesting species by Herring Gulls is considered by some authorities to be infrequent (Bent, 1921:112). They are, however, known to take eggs of various ground-nesting species (Tinbergen, 1953), in- cluding those of the Oldsquaw (Sutton, 1932:263-264). This latter fact, coupled with the high numbers of Herring Gulls known to be present at Ghurchill, suggests that it would be unrealistic to exclude the Herring Gull as a potential egg predator of Oldsquaws in this region. Although less abundant than the Herring Gull, Parasitic Jaegers and Ravens were observed throughout the area in both 1967 and 1968. Accord- Roger M. Evans OLDSQUAW- ARCTIC TERN ASSOCIATION H87 ing to Kortwright (1953:283), jaegers, along with various other predators, may “take a heavy toll” of Oldsquaw eggs. Sutton (1932) also cited the Parasitic Jaeger as a predator of Oldsquaw eggs, and cited observations of jaegers taking Oldsquaw young. The Raven, according to Larson (1960), may also constitute an important egg predator of the Oldsquaw. Despite the presence of the above predators, loss of Oldsquaw clutches at Churchill was limited. On islands in fresh-water ponds, no predator-destroyed clutches were found in 1967, even when nests were visited repeatedly, every one to two days, by one or more observers. In 1968, two clutches, found prior to the onset of nesting by the terns, were missing on subsequent visits to the islands, and may therefore have been destroyed by predators. On the beach, one nest was destroyed within an abandoned tern colony. This loss, however, was apparently due to wave action rather than to predation. On the mainland tundra, at least two, and possibly three, nests were destroyed, presumably by predators. Taken together, these figures indicate that at most, no more than five of the 28 nests (18 per cent) were destroyed by predators. This percentage loss of clutches compares favorably with egg loss (average 22.9 per cent ) of several anatid species nesting in larid colonies located on islands in the Gulf of Bothnia (Hilden, 1964), but is somewhat greater than that for Gadwall (Anas strepera) and Lesser Scaup {Aythya affinis) nesting- in association with Larus spp. in Alberta, where 89-90 per cent of the nests hatched (Vermeer, 1968). DISCUSSION In the absence of comparative data from areas where egg predators are absent or where terns and Oldsquaws do not nest together, definite con- clusions concerning the extent of nest protection derived by the Oldsquaws that nest in association with Arctic Terns are not warranted. Indirect evi- dence, however, is provided by instances in which avian predators have been attacked and driven away by Arctic Terns, as described for the Herring Gull by Sutton (1932), Bullough (1942), and Sutton and Parmelee (1956). Active defense by Arctic Terns of their nest sites against Parasitic Jaegers (Anderson, 1913; Sutton, 1932; Lovenskiold, 1954) and Ravens (Sutton, 1932; Larson, 1960) have also been documented. Instances in which Arctic Terns attacked and chased these species were also observed during the present study at Churchill. There thus seems little reason to doubt the interpretation of Anderson (1913), Larson (1960) and others that such attacks by Arctic Terns provide a measure of protection for birds that nest in or near their colonies, and that such nest associations are therefore commensal relationships. The data obtained at Churchill suggest, however, that the commensal relationship between Oldsquaws and Arctic Terns is of significance primarily for nests located on islands (cf. also Larson, 1960; THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Delacour, 1959:174-175), and possibly for those located on the beach, but is probably of less importance for nests located on the mainland tundra. The most parsimonious explanation of the proximate mechanisms under- lying the association between Oldsquaws and Arctic Terns is that of similar habitat preferences by two compatible species. At Churchill, this simple interpretation would seem sufficient for nests located on the mainland tundra, where distances between nests of the two species were comparatively great, hut it does not appear sufficient to account for the close association in other habitats, particularly on islands in fresh-water ponds. In these latter areas, some form of active selection of one species by the other seems likely. According to the general hypothesis advanced by Koskimies ( 1957 ) , the development of positive associations between Oldsquaws and Arctic Terns could be attributed to the active selection of tern colonies by Oldsquaws that have been imprinted, as ducklings, to terns that were present in the vicinity of their nest. At Churchill, it was evident that opportunities for auditory or visual imprinting of Oldsquaw ducklings to Arctic Terns typically occurred at hatching. The extent to which such imprinting might influence subsequent choice of nest site by the ducks remains problematical, however, in part due to the early arrival of the Oldsquaw, which may precede the arrival of the terns on the breeding grounds (Taverner and Sutton, 1934). In addition, in at least six instances in 1968, Oldsquaws at Churchill had laid clutches prior to the onset of laying by terns on the same islands. A possible supplement to the imprinting hypothesis was suggested hv observations at Churchill of Oldsquaw nest cups, remaining from previous years, on the islands in fresh-water ponds. These old nests, which numbered as high as 10 on a single island measuring no more than 10 by 5 m in size, indicate that, like the Arctic Tern (Cullen, 1956), Oldsquaws may use tradi- tional nesting areas from year to year. Where this tendency is prevalent, then once a nesting Oldsquaw became established in or near a tern colony, association in the same area would he perpetuated in subsequent years regardless of which species commenced nesting first in any particular year. The initial association, according to this interpretation, could presumably arise either as a chance result of similar habitat preferences of the two species or as a result of imprinting. According to evidence reviewed by Hilden (1965:68) fidelity to a tradi- tional nest site is more likely to occur in the absence of nest disturbance or predation. If true for Oldsquaws, then nests located away from tern colonies, if destroyed by predators, would tend to be shifted to a different location in the following year, whereas those located in tern colonies, where predation is less likely, would tend to he placed in the same location in suhsequent years. Such differential predation and nest site fidelity cannot therefore be excluded Roger M. Evans OLDSQUAW-ARCTIC TERN ASSOCIATION 389 as a possible additional mechanism favoring the accretion of Oldsquaw nests in or near tern colonies. If imprinting alone constituted the proximate cause of associations between Oldsquaws and Arctic Terns, a more or less random distribution of local areas in which associations do or do not occur would he expected. In particular, it would not be expected that the occurrence of associations would necessarily he concentrated in those areas where avian nest predators are locally abundant. According to the alternative view, that associations may he initiated either by similar habitat preferences or imprinting, but are then favored hy the tendency of Oldsquaws to use traditional nest sites that are protected from nest predators by Arctic Terns, maximum association in areas where nest predators are abundant would be expected. Further investigations of association between these species, with particular reference to the presence or absence of local populations of avian nest predators, should therefore provide information as to the relative importance of these various mechanisms, all of which must be considered tenable on the basis of existing data. SUMMARY A high incidence of nest association between Arctic Terns and Oldsquaws was found at Churchill, Manitoba, in 1967 and 1968. Distances between nests of these species averaged only 2.3 m on islands in fresh-water ponds, increased to an average of 13 m on mainland beach sites, and reached 72 m on mainland tundra. Potential avian predators of Oldsquaw eggs included the Herring Gull, Parasitic .laeger, and Common Raven. Clutches lost to predators did not exceed a maximum of five of 28 nests observed. Observations of Arctic Terns attacking potential predators suggested that Oldsquaws derived protection from nearby terns. It is suggested that such protection, coupled with a tendency to return to successful nest sites in successive years, affords a possible supplement to habitat preferences and imprinting of ducks to terns as the proximate mechanism responsible for the maintenance of nest associations between tliese species. ACKNOWLEDGMENTS This study was financed hy grants from the Northern Studies Committee, University of Manitoba, and the National Research Council (Ottawa). M. McNicholl and 1). Krindle provided valuable assistance in the field. Thanks are extended to the staff of the Churchill Research Range for providing facilities and ready access to the study area. Comments on an earlier draft of the manuscript hy D. A. Boag are gratefully ac- knowledged. LITERATURE CITED Anderson, R. M. 1913. Report on the natural history collections of the expedition, pp. 436-527, In Stefansson, V. My life with the Eskimo. Revised ed., 1951. The Macmillan Co., New York. Bailey, A. M. 1925. A report on the birds of northwestern Alaska and regions adjacent to Bering Strait. Part IV. Condor, 27:164-171. Bailey, A. M. 1943. The birds of Cape Prince of Wales, Alaska. Proc. Colorado Mus. Nat. Hist., 18:1-113. 390 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Bent, A. C. 1921. Life histories of North American gulls and terns. U. S. Natl. Mus. Bull. 113. Reprinted 1963, Dover Publ. Inc., New York Bent, A. C. 1925. Life Histories of North American Wild Fowl, Part 11. U. S. Natl. Mus. Bull., 130. Reprinted 1962, Dover Publ., Inc., New York. Bullougii, W S. 1942. Observations on the colonies of the Arctic Tern (Sterna macrura Naumann) on the Fame Islands. Proc. Zool. Soc. London, (A) 112:1-12. Burton, P. J. K., and M. H. Thurston. 1959. Observations on Arctic Terns in Spitsbergen. Brit. Birds, 52:149-161. Coocii, F. G. 1967. Review of: Delacour, The waterfowl of the world, Vol. 4, 1964. Auk, 84:135-138. Cullen, J. M. 1956. A study of the behaviour of the Arctic Tern (Sterna macrura). Unpubl. D. Phil. Thesis, Oxford. Delacour, J. 1959. The waterfowl of the world. Vol. 3. Country Life Ltd., London. Gudmundsson, F. 1956. Islenzikir fuglar XIV Kria (Sterna paradisaea) . Nat- turufraedingurinn, 26:206-217. Hawksley, 0. 1957. Ecology of a breeding population of Arctic Terns. Bird-Banding. 28:57-92. Hilden, O. 1964. Ecology of duck populations in the island group of Valassaaret. Gulf of Bothnia. Ann. Zool. Fenn., 1:153-279. Hilden, 0. 1965. Habitat selection in birds. Ann. Zool. Fenn., 2:53-75. Kortrigiit, F. H. 1953. The ducks, geese and swans of North America. Stackpole Co., Harrisburg. Koskimies, j. 1957. Terns and gulls as features of habitat recognition for birds nesting in their colonies. Ornis Fenn., 34:1-6. Larson, S. 1960. On the influence of the Arctic Fox Alopex lagopus on the distribution of Arctic birds. Oikos, 11:276-305. Lovenskiold, H. L. 1954. Studies on the avifauna of Spitsbergen. Norsk. Polarinst. Skrifter, 103:1-131. Pliillips, j. C. 1925. A natural history of the ducks. Vol. HI. Houghton Mifflin Co., New York. Sutton, G. M. 1932. The birds of Southampton Island. Mem. Carnegie Mus., Vol. 12, Part H, Sect. 2. Sutton, G. M., and D. F. Parmelee. 1956. On certain Charadriiform birds of Baffin Island. Wilson Bull., 68:210-223. Taverner, P. A., and G. M. Sutton. 1934. The birds of Churchill, Manitoba. Ann. Carnegie Mus., 23:1-83. Tinbergen, N. 1953. The Herring Gull's world. Collins, London. Vermeer, K. 1968. Ecological aspects of ducks nesting in high densities among larids. Wilson Bulk, 80:78-83. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MANITOBA, WINNIPEG, CANADA 2 APRIL 1969. SEASONAL CHANGES IN FLOCKING BEHAVIOR OF STARLINGS AS CORRELATED WITH GONADAL DEVELOPMENT G. James Davis This paper presents data on the seasonal variation in population and flock- ing behavior in Starlings (Stunms vulgaris) as correlated with gonadal changes. Most research of Starlings has considered specifically the breeding biology (Kliujver, 1933; Marples, 1936; Bullough, 1942; Kessel, 1957; and Collins and deVos, 1966 ) or the aggregations of Starlings (Wynne-Edwards, 1929; Brown, 1946; Davis, 1955; and lumber, 1956) with little attention focused on the relationship between the two. With the aid of four weekly census routes to determine the extent of seasonal variation in Starling popu- lation and flocking behavior, the relation between the flocking behavior of Starlings and the reproductive cycle is presented. MATERIALS AND METHODS Most data were collected in McDonough County, Illinois between 27 June 1965, and 25 June 1%6, from four, 25-mile census routes designed to include the four predominant ecological-land use patterns in west-central Illinois. One census route was located such that over 90 per cent of the land adjacent to the road was intensively farmed; the predominant soil type was dark silt loam. A second route was located where 39 per cent of the land was under cultivation while the remainder was composed of oak-hickory forest or woodlots and bluegrass pastures situated on a silty clay loam soil. The other two routes represented situations intermediate to that for the two routes described above. Each route was covered once a week by automobile driven at 25 miles per hour beginning 30 minutes after sunrise. Censuses included only those Starlings located within a 100 yard radius of the car. If possible, censuses were not taken on days when visibility was poor or when it was raining at the starting time as these conditions usually caused counts to be lower than on clear days at the same time of year. Starlings observed along the routes were recorded as to number, activity, adjacent cover, relationship to farm complexes and location on the transect. Starlings were recorded as perching if sitting above ground level and not engaged in feeding activity. Any Starling sitting on the ground was recorded as feeding. Flying was the third type of general activity recorded. Weather conditions at the time of each observation also were recorded. Supplementary data were obtained from 28 morning and 55 evening observations of Starling activity at communal roosts in tbe Macomb, Illinois area between 10 July 1965, and 28 October 1965, and by random observations of Starlings throughout the study. RESULTS AND DISCUSSION Annual Changes in Population Levels. — As reported by many workers (Marples, 1936; McAtee, 1940; Ball, 1945; and Kessel, 1957) recently fledged Starlings occur in flocks varying in size from five to over 300 birds 391 392 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Fig. 1. The numbers of Starlings observed per 100 miles on four, 25-mile census routes each of which was driven once a week from 27 June 1965, through 25 June 1966, McDonough County, Illinois. throughout June. During late June formation of juvenile flocks caused the census counts to increase from 150 birds to over 300 birds per 100 miles ( Lig. ll. However, from 3 July through 24 July few Starling flocks, adult or juvenile, were observed and counts along the census routes declined to about 100 birds per 100 miles — one of the lowest levels of the study (Lig. 1). There are few data in the literature concerning observations of Starlings during July which I interpreted as reflecting this low level of Starling activity in July. Random observations of Starling flocks by the author during July and August, 1967, and June and July, 1968, near Madison, Wisconsin further supported the hypothesis that Starling activity is at one of the lowest levels of the year in July. A possible explanation for this low population density and low level of activity in July is that the young birds migrate north- ward from the general area where they were fledged. Niethammer (1937) reported such movements in Switzerland where young Starlings migrated to the vicinity of the North Sea soon after the juvenile flocks formed. An alternative hypothesis is that the low numbers observed in July are a mani- G. James Davis STARLING FLOCKING BEHAVIOR 393 Fig. 2. Numbers of Starlings observed at communal roosts near Macoml), Illinois, during the period 12 July 1965, through 10 Octoljer 1965. festation of the initial stages of summer molt. According to Kessel (1957) the postjuvenal molt of Starlings begins four to six weeks after the young birds have been fledged. Therefore, in Holland (Kluijver, 1933), New York (Kessel, 1957), Ontario (Collins and deVos, 1966), as well as Illinois (Davis, 1966) the postjuvenal molt for the first brood would begin in the early part of July, the period corresponding with the observed decrease in numbers seen during July in Illinois and Wisconsin (Fig. 1). Presumably while molting Starlings are less active and so are less conspicuous to the observer, and their behavior might be of a more secretive nature during this time. Following these periods of low populations Starling numbers recorded increased gradually and by 21 August a level of 275 birds per 100 miles was recorded (Fig. 1). After 21 August the numbers increased rapidly to about 1500 birds per 100 miles and remained at that level from 20 September through 9 October (Fig. 1). During August and September in the Macomb area the number of communally roosting Starlings also increased rapidly to the highest level recorded for the study. By late August numerous small flocks using MEAN NO PER UNIT 394 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 -4000 -3500 — 3000 -2500 -2000 — I 500 — 1000 — 500 MONTH to £ e _) o > < Q < Z o o < ijJ Fig. 3. The average Starling flock size, by monthly periods, observed on four 25-niile census routes each of which was driven once a week from 27 June 1965, through 25 June 1966, in McDonough County, Illinois in relation to average monthly volume of Starling testes as adopted from Bullough (1942) and Johnson (1967). (). James Davis STARLING FLOCKING BEHAVIOR ;t;5 lempoiary roosts had consolidated into one large flock using a single com- munal roost (Fig. 2). The tendency of Starlings to aggregate was noticealde in the census counts, for as the population increased through August the number of individual flocks observed decreased from 45 per 100 miles ( 25 July through 31 July) to 27 per 100 miles (15 August through 21 August). Ihis late summer change in flocking behavior is reflected more dramatically in the average flock size which was two and one-half birds in July while in August, the average flock size had increased to over eight birds per flock (Fig. 3). From these results it would appear that the southward migration of the northern adult Starling populations began as soon as August flocking oc- curred. Bullough (1942 ) after completing a study on the reproductive cycles of British and Continental Starlings concluded that sex hormones in the blood inhibited fall migration (Fig. 3). He believed that as the gonads decreased in size, reaching their smallest size in July and August, the amount of sex hormone released into the blood decreases and the birds are induced to migrate southward. Once Starlings begin southward migration they are thought to travel slowly and leisurely along definite routes. A few handing returns from west-central Illinois suggest that Starlings migrate into and out of west-central Illinois by two different routes; one to the northeast along the Illinois River and along either side of Lake Michigan and the other along the Mississippi River (C. Martin, unpuhl. data). The west-central Illinois study area is situated midway between these two flyways and so, the period of maximum population density, 20 September through 9 October ( Fig. 1 ) , probably represents the convergence of migrating Starlings from these two migration paths. These migrating birds appear to remain in the west-central Illinois area through September as a settled population feeding throughout the day in large flocks in hog and cattle pastures, and roosting communally at night. This period of high population density, 20 September through 9 October, was followed by a sudden decrease in the Starling population to about 400 birds per 100 miles of census route, which in turn was followed by a marked increase to about 800 Starlings per 100 miles during the week of 18 October through 24 October (Fig. 1). The following week of 25 October through 31 October, the Starling population again returned to a level of 400 birds per 100 miles. Throughout this entire period, 10 October through 31 October, no large feeding flocks or communally roosting Starlings were observed in the Macomb area (Fig. 2j. The sudden decrease in population which occurred during the week 10 October through 17 October is thought to he the result of most of the adult population migrating southward from the west-central Illinois area because 396 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 of food shortage and cooler fall temperatures. A possible explanation for the second peak in population density during the period 18 October through 24 October is that young Starlings were migrating through the area after the adults already had migrated. As stated previously, Niethammer (1937 ) reported northward movement by juvenile Starlings after fledging. Because of this summer movement northward, he suggested that young birds would migrate south later than the adults. This hypothesis is further supported by the observations in Illinois that during this second period of high population density no communal roosts were found in the west-central Illinois area and flying Starlings constituted a larger proportion of the censused population than at any other time of the study (Ligs. 1 and 2). The data indicate that these Starlings were passing through the area rather quickly. During the period November through Lebruary, Starlings remaining in the area for the winter were observed roosting only in small groups in natural cavities and buildings and they fed nomadically throughout the day near cattle and hog feedlots or refuse areas. Census counts throughout the winter fluctuated with weather conditions; i.e., severe winds or cold temperatures made the birds less active and thus less conspicuous to the observer resulting in lower census counts (19 December through 25 December and 26 January through 1 Lebruary). During the colder part of the winter, 13 December through 26 Lebruary census counts dropped 48.1 per cent to slightly over 100 Starlings per 100 miles (Lig. 1). Part of the observed winter decrease in Starling numbers can he inter- preted as winter mortality which according to Kessel (1957) is nearly 25 per cent of the spring population. However, most of the observed decrease in Starling population during the winter is thought to have been the result of “weather movements,” i.e., when increasingly cooler temperatures oc- curred in an area birds migrated to warmer climates and to a more available food supply. During Lebruary the average flock size decreased from over 6.5 birds per flock to near 2.5 birds per flock (Lig. 3). At this time Starlings began showing an interest in potential nest sites as also observed by Kluijver (1933), Marples (1936) and Kessel (1957). During the period 27 Lebruary through 6 March, the first signs of additional birds migrating into west -central Illinois were observed as population levels increased from 120 birds per 100 miles to over 300 Starlings per 100 miles of census route (Lig. 1). These Lebruary observations are difficult to interpret. The interest shown by the permanent residents in potential nest sites is believed to be the effect of rapidly increasing gonadal activity preceding the approaching nesting season ( Bissonette and Chapnick, 1930 and Bullough, 1942 ) . Bullough ( 1942 ) in his study of reproductive cycles of Starlings (Fig. 3) concluded that the C. Janies Davis STARLING FLOCKING BEHAVIOR 397 increase in gonadal activity in Fel)ruary caused higher levels of sex hormones in the blood which stimulated the Starlings to migrate in the spring (Fig. 3). Spring migration is accomplished in a different manner than fall migration (Fig. 1). Spring migration in France ( Quepat, 1874) and New York (Kessel, 1957) also occurred in the first part of March. Szmirnov (1929-30) reported the rate of spring migration in Finland and South Russia was 32 miles per day. If Starlings migrate in Illinois at the rate of 32 miles a day, it seems probable that Starlings migrate in a less gregarious manner and over a longer period of time in the spring than in the fall since spring migration did not show dramatic increase of Starling population or the large flocks associated with fall migration (Fig. 1). Through Alarch and April the Starling population in west-central Illinois remained at between 250 and 300 birds per 100 miles of census route, even though Starlings still were migrating through the area (Fig. 1). The spring population is composed of two distinct Starling groups, the nesting popula- tion and the nonbreeding or migratory population. The nesting population always was near potential nest sites, perching, displaying, or building nests. The nonbreeding or migratory population showing only slight gonadal activity (Johnson, 1967) occurred in small flocks flying in open fields or perched near farm feedlots. After spring migration and during the height of the nesting season, 20 April through 26 May, the Starling population as determined from the census routes, was low, or about 100 birds per 100 miles of census routes (Fig. 1). The number of Starlings did not increase appreciably until after the fledged young of the first brood were being observed in late May and throughout June. Then Starling population levels increased to over 250 birds per 100 miles during the last week of the census, 19 June through 25 June. The decline in population during the nesting season can be attributed to the fact that one half of the adults were at the nest sites incubating eggs or brooding the young and could not he observed during the census. The gradual increase in population in May and June was the result of first family units being observed ( Marples, 1936 j and later the formation of the juvenile flocks (Kessel, 1957). Flocking Behavior. — The flocking behavior of Starlings is distinctly dif- ferent in two periods of the year: there is a 6-month period during which there is a tendency to flock and a 6-monlh period during which there is almost no tendency to flock (Fig. 3). During August, 1965, the average flock size increased suddenly from 2.5 birds per flock to nearly 8 birds per flock. Then for the next five months the average flock size decreased gradually until January when the average was about 6.5 birds per unit. In February the average flock size fell sharply to 2.5 Starlings per flock where it re- THE WILSON BULLETIN December 1970 Vol. 82, No. 4 o ( u ) oyu mained through July, except for a slight increase in average flock size during June resulting from the formation of juvenile Starling flocks (Lig 3). If gonadal volume of male Starlings of the west-central Illinois population (Johnson, 1967) and an English population (Bullough, 1942) are plotted in relation to the average monthly flock size as determined hy the census routes in this study (Lig. 3), it appears that as the gonadal size increases (which is a general indicator of the amount of sex hormone produced ) average flock size decreased. I suggest that the tendency to flock among Starlings is inversely related to the level of sex hormones in the blood. This is further supported hy observations in the spring that flocking birds show little or no gonadal development (Kessel, 1957). SUMMARY 1) Starling populations in west-central Illinois dropped to one of its lowest levels of the year in July 1965 (100 birds per 100 miles of census route) as a result of either young Starlings migrating northward or the postjuvenal molt making the Starlings less active flyers and less conspicuous to the observer. 2) The initial stages of migration were observed in August as the average flock size increased from 2.5 birds per unit to over 8 birds per unit. From this time the Starlings began to accumulate until populations reached a peak of over 800 Starlings per 100 miles of census route during the period 26 September through 2 October. 3) The migration from further north of young Starlings through west-central Illinois after the adults already had migrated through was thought to be the cause of a second peak in the population to nearly 800 birds per 100 miles of census route in late October. 4) Starling populations gradually declined over the winter from 250 birds per 100 miles to about 100 birds per 100 miles of census route as a result of “weather movements." 5) In late February the average flock size decreased from 6.5 to 2.5 birds per unit as some Starlings began showing an interest in potential nest sites. 6) Spring migration into west-central Illinois which began in the first week of March did not exhibit the large flocking tendency of fall migration and it occurred over a longer period of time. 7) During the nesting season the numbers of Starlings observed along the census routes were low, about 1(X) birds per 100 miles of census route, because the adults were confined to the vicinity of the nest hy nesting activities. The numbers along the census routes did not increase again until June when the fledged young formed into juvenile flocks, and the counts rose to near 300 birds per 100 miles of census route. 8) The flocking of Starlings was of two distinct types: during August through January, there was a tendency to gather into large flocks and during February through July, there was a tendency to occur only in pairs. It is believed that the tendency to flock among Starlings is inhibited l)y the level of sex hormones in the blood. ACKNOWLEDGMENTS 1 am grateful to Dr. John E. Warnock and Dr. J. Henry Sather for advice and assistance throughout the study; and to John Dallman, Illustrator, Department of Zoology, The University of Wisconsin for preparation of the graphs. This study was supported hy the Illinois Department of Conservation and the United States Fish and Wildlife Service under Pittman-Rohertson Project Number 74-R. G. James Davis STARLING FLOCKING BEHAVIOR 399 LITERATURE CITED Ball, S. C. 1945. European starling in Gaspe. Auk, 62:79-97. Bissonnette, T. H. and M. H. Ciiapnick. 1930. Studies on the sexual cycle in birds. II. The normal progressive changes in the testis from November to May in the European Starling (Sturmis vulgaris), an introduced, non-migratory bird. Amer. J. Anat., 45:307-343. Brown, E. J. 194A. A Cheshire starling roost. 1944-45. J. Anim. Ecol., 15:75-82. Bullougii, W. S. 1942. The reproductive cycles of the British and Continental races of Starling (Sturnus vulgaris L.). Phil. Trans. Royal Soc. (London), B231 :165-246. Collins. V. B. and A. deVos. 1966. A nesting study of the Starling near Guelph, Ontario. Auk, 83:623-636. Davis, D. E. 1955. Population changes and roosting time of Starlings. Ecology, 36: 424-430. Davis, G. J. 1966. Reproduction and seasonal changes in flocking behavior of Starlings iSturnus vulgaris L.). Unpubl. Master’s thesis. Western Illinois University, Macomb, Illinois. Johnson, N. P. 1967. Seasonal changes in reproductive organs of the Starling (Sturnus vulgaris L.). Unpubl. Master’s thesis. Western Illinois University, Macomb, Illinois. JUMBER, J. F. 1956. Roosting behavior of the Starling in central Pennsylvania. Auk, 73:411-426. Kessel, B. 1957. A study of the breeding biology of the European Starling (Sturnus vulgaris L. ) in North America. Amer. Midi. Naturalist, 58:257-331. Kluijver, I. H. N. 1933. Bijdrage tot de biologie en de ecologie van den spreeuw (Sturnus vulgaris vulgaris L.) gedurende zijn voortplantingsti. Versl. Meded. Plantenziektenkundigen dienst Wageningen 69:1-145. Marbles, G. 1936. Behavior of Starlings at nesting site. Brit. Birds, 30:14-21. McAtee, W. L. 1941. An experiment in songbird management. Auk, 57:333-348. Niethammer, G. 1937. Handbuch der Deutschen Vogelkunde. Akademische Verlags- gesellschaft. (Leipzig). Quepat, N. 1874. Ornithologie Parisienne. Paris. Szmernov, N. 1929-30. A seregely tavaszi folvonulasa Keleteuropaban es Nyugats- ziberiaban. Aquila, 36/37:95. Wynne-Edwards, V. S. 1929. The behavior of Starlings in winter. Brit. Birds, 23: 138-153. WESTERN ILLINOIS UNIVERSITY, MACOMB, ILLINOIS (PRESENT ADDRESS: DEPART- MENT OF ZOOLOGY, UNIVERSITY OF WISCONSIN, MADISON, WISCONSIN 53706). 24 SEPTEMBER 1968. SPATIAL DISORIENTATION IN BIRDS A. D. Herbert The aircraft was on final approach through the rain and fog. At ap- proximately 500 feet it went into a spiral dive to starboard, striking the right wing against the approach lights. The aircraft was destroyed. Blackburnian Warblers were migrating on a night of a low ceiling and the visibility restricted in moderate rain. On reaching a floodlighted area, some fifty birds crashed into a hangar and were killed. Initially there does not seem to be much in common, except the weather, in these two unfortunate occurrences. Yet, under analysis, there may he a great deal of similarity. In both cases the fliers were attempting to fly through deteriorating weather conditions, picking their way through a maze of light and shadow, of reflected and refracted light shining through rain, an opaque obstructing medium. It is suggested that the cause of both the crashes was exactly the same. The fliers became confused by the abruptness of intense lighting, and, using the primary sense of orientation (sight) in conjunction with erroneous sensory stimuli, suffered a complete loss of spatial orientation. Birds, particularly the nocturnal migrants when flying at low level are susceptible to, and suffer from vertigo and spatial disorientation the same as man. For the purpose of this discourse it is assumed that: (a) the aerodynamic forces acting on the wings of a bird are the same as those acting on the wings of an aircraft; (b) only nocturnal migrants are under consideration; (c) the sense organs are used for the same basic purposes in both birds and man ; and ( d ) while the senses of the bird may be more acute, the psycho- physiological reactions to the stimuli are similar in birds and man. Although the aerial environment is applicable to both birds and man, each has its own peculiar environment in which it flies and this is not readily examinable by direct observation. This environment is made up of stimuli appreciated by sensory organs and perceived by the brain. The reactions to the stimuli are based upon knowledge, and each reaction must be correct in the proper place at the proper time. Because the human pilot is sensitive to similar stimuli, man can visualize the aerial world of other fliers. It is only through a comparison of the bird with man’s knowledge of flying that we can deduce how a bird flies. As spatial disorientation is extremely cominon (90 per cent incidence) amongst all-weather pilots, the most expedient way of determining the hap- penings and causes of spatial disorientation in birds is to consider first the human pilot. 400 A. D. Herbert SPATIAL DISORIENTATION 401 THE HUMAN PILOT Before discussing the orientation senses in relation to flying, let us review the actions of the senses of orientation governing the locomotory organs. These organs have the sole purpose of propelling the body or appendages in a given direction for a given distance. Under certain circumstances these organs can become useless, as when the governing apparatus, the orientation senses, is impaired in its function. Consider the children’s game of Blind- Man’s-Buff or Pin-The-Tail. The child is subjected to a mild case of vertigo, or spatial disorientation, and is asked to achieve a specific goal. Although the locomotory organs are functioning perfectly, the orientation senses are im- paired causing an erratic approach toward the target. Although the child is subject to gravity, it has difficulty in maintaining a vertical orientation. It is therefore reasonable to conclude that controlled locomotory action is de- pendent upon spatial orientation. For the human on the ground, spatial orientation is necessary only within a two dimensional field. The aviator must have a true spatial orientation. He must be capable of determining a three-dimensional move; of assessing his position relative to a fixed object (the runway) and a moving object (another aircraft); and of determining his position relative to the horizon. Flying on a cloudless day, the pilot is at the center of a vertical hemisphere. When he is straight and level the ground occupies the bottom half of his visual field and the sky the upper half. The pilot can fly a straight line across the ground because he can see where he is going. During a level hanked turn, the horizon rotates at the middle of the visual sphere, going up on one side and down on the other. It is interesting to note that the pilot’s immediate reaction is to reorient himself by moving his head and body to maintain a proper horizontal and vertical alignment with the horizon. If the pilot in- creases the bank but maintains a straight course, his orientation senses will in- form him of a side-slip. However, if the bank is made in a turn, the acceleration forces may indicate the turn, or something entirely different, depending on the severity and smoothness of the turn and the forces involved. If the pilot exerts a heavy back pressure or forward pressure on the control column, the orientation senses will inform him of accelerations in these directions even to the extent of overriding the forces of straight and level flight. However, the orientation senses are not as acute as vision in their perception of changes in speed and direction. The discrepancies between the senses (sight and balance) in flight lead to certain orientation problems peculiar to flying. Prior to the development of specialized instrumentation, the pilot had to remain in sight of the ground because there was no means of establishing a horizontal or vertical datum from which to orientate himself. Even today, with modern instrumentation. 402 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 pilots are still subject to attacks of vertigo and spatial disorientation, even to the extent of crashing. Studies have shown that disorientation is, almost without exception, the result of normal psychophysiological processes associated with certain characteristics of flight and of the pilot aloft ( Clark and Graybiel, 1955). Therefore, disorientation could be considered to be normal in the sense that it is a perceptual process correlated with the sense organs function- ing normally in an abnormal environment. There are certain characteristics peculiar to flight which make orientation in the air more difficult than on the ground: (a) In flight the pilot loses contact with the ground. He lifts himself above the normal visual aids used to maintain a vertical orientation, i.e. trees, buildings, etc., and is forced to use the horizon to maintain the attitude he desires, (b) The pilot must maintain a three-dimensional orientation, direction, distance, and altitude. The pilot must be aware of his spatial position with respect to the horizon, to fixed objects and to moving objects, (c) The pilot must appreciate the unusual physical forces to which he will be subjected. In the air, while still subject to gravity, he is also subject to accelerative forces which may be continuously changing both in magnitude and direction, even to the extent of negating gravity, (d) The speed and altitude of the aircraft impose further stresses on the senses of the pilot. A more acute sense of spatial orientation is required for flight near the ground than at high altitudes. The increase in availability of visual cues closer to the ground may not necessarily increase the ease of orientation; the abundance of cues may, in fact, lead to confusion. Similarly, spatial disorientation at high altitudes may occur because of the greater sparsity of visual cues. The above is very basically the pilot’s problem in maintaining spatial orientation and he must learn to appreciate these problems before he can fly. However, there are additional problems which may impose further stresses: ( a ) Visual cues may be reduced or be missing entirely. In the air, gravity is a minor cue, and the horizon may be completely obscured. Thus the pilot is forced to use his instruments to obtain a reference to the horizontal. In this situation he has an indication of his attitude, but his relative position to external objects is completely unknown, ( b ) Lalse cues may be presented to the pilot by natural phenomena outside the aircraft. Cloud formation, precipitation, lights, reflections and refractions of lights, Aurora Borealis, etc., all may cause spatial disorientation. Accelerations may override gravity and be substituted for gravity, particularly if the accelerations are main- tained for a prolonged period, (c) The discrepancies which exist between the senses themselves and between the senses and the instruments may be exaggerated when the “G” forces of a tight turn override gravity and indicate the vertical is in the direction of the force while the instruments indicate A. D. Herbert S P A 11 AL Dl SOKI ENTA 11 0 N 40;5 llie vertical in another direction. There is also the phenomenon of recovering from a turn and still having the impression of being in a turn, although the visual cues belie the sensation. There are other factors which must he considered. A seemingly minor point, but actually a very important one, is that the vertical axis is usually obtainable only when a horizontal reference is provided while flying. The vertical axis is the predominant one to a person on the ground; yet when flying, it cannot be accurately determined by itself. Therefore, the horizontal axis becomes the predominant axis. The establishment of the horizontal datum is vital to spatial orientation, as all flying is based upon the aircraft’s attitude relative to the horizon, not to the vertical. Graybiel (1951) states, “Visual perception may become inadequate for partial spatial perception due to inadequate perceptual data. There are many causes for this centering around (1) celestial factors such as darkness, brightness of sun etc., (2) atmospheric conditions such as rain, fog, etc., (3) inadequate visual framework and (4) factors relating to the plane such as small size of windows, glare, etc.” Another cause can be ground lighting such as street lights, approach lights, floodlighting. While no statistics are available, it is suggested that the majority of the cases of spatial disorientation occur at night. The optimum conditions for spatial disorientation seem to be a night with low cloud and moderate to heavy precipitation, and the aircraft near, (within 2000 feet) or in the base of the cloud. If the aircraft is near any illuminated area, flying becomes a difficult task, because the pilot is subject to sporadic visual cues which are readily misinterpreted. The re- fracted and reflected surface lighting is coming from angles which are not usually experienced. There is a pronounced diffusion of surface lighting in precipitation similar to the haloes around the sun or moon when seen through cirrus or thin alto-stratus cloud. The horizon is no longer easily identifiable. It is under these circumstances, particularly if the pilot is trying to fly partly with reference to outside visual cues and partly on instruments, that spatial disorientation is most likely to occur. Armstrong (1952:281) states, “It has been established beyond all doubt that vision is absolutely necessary for aerial equilibrium. If vision is elimi- nated during flight, all of the other organs of equilibrium have been found inadequate and the pilot becomes hopelessly confused.” Davis (1953) states “It is apparent that the normal vestibular apparatus is not sensitive enough for aerial equilibrium and due to the illusion of reversal of motion it may be, under certain circumstances, a distinct hazard to flight.” In the light of these two quotations it would appear that the visual sense is the predominant sense of spatial orientation while the vestibular apparatus has a questionable role. Guyton (1961:678-79) states, “In summary, then, the semicircular canals 404 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 detect the rate of change of rotation, which is called angular acceleration. 4 he function of the semicircular canals, therefore, could not possibly be to maintain static equilibrium during linear acceleration, or when a person is exposed to steady centrifugal forces.” The tactile, visceral, and proprioceptive senses each contribute to the general perception of orientation but are in- capable, either individually or in concert, of correctly and exactly orienting the pilot in the air, or interpreting the direction of the forces acting upon him. A final point to be considered is the background knowledge of the pilot. Graybiel (1951) states, “Spatial orientation may be looked upon as a phenomenon of perception which represents the individual’s interpretation of stimuli originating in various organs of special sense.” Interpretation of stimuli is the correlation of the visual cues with the other sensory cues. 4Te interpretation must be based on knowledge which is derived either from previous experience or some other source. However, the knowledge used may be very basic or minimal, or it may be based on assumptions of the normal. In attempting to rationalize the situation, the pilot may accept false cues, both visual (physical) and sensory, as true cues and react accordingly. Therefore, under flying conditions which tend to promote spatial disorienta- tion, there must be a conscious reasoning and knowledge of the problems of orientation or complete vertigo and spatial disorientation is the usual result. Restoration of spatial orientation can be achieved only through a correct interpretation of the accepted visual cues. To summarize, the following two major groups of factors must be accepted: Physiological Factors. — (1) Sight is the most important sense associated with spatial orientation. (2) The vestibular, tactile, visceral, and propriocep- tive senses eacn contribute a small part of the necessary intelligence to main- tain orientation, but these senses are not generally effective, either in concert or individually, and may at times contribute to disorientation. ( 3 ) Knowledge and ability to assess both visual ( physical ) and other sensory cues is es- sential to maintaining or regaining spatial orientation. Knowledge of the phenomenon itself is vitally important. Physical Factors. — (1) The loss of visual cues by darkness, precipitation or fog, or any combination thereof; (2) inexperience in flying in such con- ditions that visual cues are lost; (3) conflict between the cues to orientation. This may be a conflict between visual and other cues, particularly when centrifugal force replaces normal gravity; (4) prolonged turns at a constant speed with rapid recovery to straight and level flight; (5) unusual maneuvers at night; (6) gradually entering any unusual position without being aware of it; (7) sudden accelerations and decelerations at night; and (8) failure of the pilot to constantly recognize his position in the three-dimensional world of flight. A. D. Herbert SPATIAL DISORIENTATION 405 THE BIRD Before proceeding with any analysis of a bird’s orientation faculties, let us review a few instances of avian crashes. In September, 1961, Blacklrurnian Warblers were migrating through the area of a Royal Canadian Air Force Base. The weather situation was one of low ceilings and restricted visibility in rain. The geographic plan of tire station is as shown in Figure 1. The fronts of the hangars (B) were floodlit facing the tarmac (E). The revolving light beacon (X) on the control tower was in operation. Tliree hundred yards east the floodlights of the Alotor Vehicle section (C) were shining on the parking area (F). The floodlight on both the hangars and the Motor Vehicle section are forty feet above ground on the fronts of the buildings, while the revolving beacon on the tower is 80 feet above ground. The lights from inside the vehicle section were shining through the opaque glass in the doors. As far as can be ascertained, the birds were flying in a south south-easterly direction as they had been during the previous five nights. Of the five birds which came to grief 406 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 against hangar (A), two were on the north end and three on the south end. No birds were found around the control tower (X), and only three along the rest of the hangar line (B). However, 30 birds were found dead in front of the Motor Vehicle section (C) and 23 more were found against a secondary garage (D) 100 yards south of (C). Re- stricted space could not he a contributing factor as there is unlimited room for the birds to avoid these obstacles. The hangars, (B) are no higher than two-storied structures. Why, then, did these birds fly into the buildings? Hochbaum (1955) reports a Mr. Don Knox, “We had a week of very foggy weather November 12 to 18 and the trees and fields of stubble were coated with hoar-frost. The sun was hidden for days and at times it was difficult to see more than ten feet ahead in daytime. On the evening of the 15th, Mr. Knox decided that it would be a good time to ljurn an old straw stack, so set it afire about 7:30 p.m. Next morning as he was driving along the road he noticed a few dead ducks scattered here and there but thought little about them as ducks often strike the telephone lines and kill themselves. A little later he noticed something unusual going on in the stubble field and went to investigate. Mr. Knox was amazed to find hundreds of dead and dying ducks, some with smashed bodies, some with broken legs and wings, and others less seriously injured but apparently dazed and unable to navigate properly.” Baldwin, (1%3) states: “In the fall of 1962 at the Long Point Lighthouse, on a night when migrants were swarming around the revolving light, the writer was dis- turbing warblers, thrushes and sparrows from the long grass at the base of the flood- light tower (a recent innovation) where they had fallen or were resting. Time and again birds would flutter up from the long grass to a height of five or six feet and then fly directly at the white concrete structure.” A report of bird kills around TV towers is contained in a study by Tordoff and Mengel (1956). In their description of the tower they state, “The tower is lighted by a series of red lights, some flashing and others steady.” These lights undoubtedly are ob- struction warning lights for aircraft. In a further paragraph they note “all major kills at Topeka occurred when the migrating birds encountered either a cold front or a stationary front lying over eastern Kansas. Typically, this frontal weather included rain, fog, and cloud ceilings down as low as 800 to 1000 feet. Weather of this type pre- sumably forces the migrating birds to fly below the cloud ceiling and thus brings them within the altitudinal range of television towers.” Stoddard (1962) cites innumerable examples of birds striking TV towers under similar weather conditions. All these towers must conform to a certain standard of illumination as provided hy various aeronautical governing agencies. Why do birds fly into these illuminated obstacles? Howell (1955) cites examples of birds being killed by ceilometers around airports. He states “that it occurs only when certain factors coincide; these are an overcast of 5000 feet or less, a wind with a velocity of at least five miles an hour from the north, and a large volume of migration. It might be added that these weather conditions are usually associated with a cold front.” Amelia Laskey (1956) notes that "On the night of September 24—25, 1955 more than 1400 birds of 51 species were killed or injured at Sewart Air Force Base, Smyrna and a few at Berry Field, Nashville. After a week of warm weather with temperatures reading 90 to 97 degrees, there was a sudden change on September 24. Rain and northerly winds prevailed with temperatures for that day ranging from 73 to 68 degrees. When the rainfall ceased in the afternoon, the cloud ceiling was only 500 feet.” Laskey (1956) reports that “at 9:45 p.m. there were hundreds fluttering rather high in the beam.” It is interesting to note Howell (1955) when he states “We concluded A. D. Herbert SPATIAL DISORIENTATION 107 that the proljahle cause of death was aerial collision l)etween migrants followed hy flying or falling against the ground. While we could not report an actual eyewitness ac- count of aerial collision hetween migrants such collisions have since been witnessed hy Capt. R. L. Edwards, at Maxwell Air Force Base, on the night of October 7-8, 1954.” Prior to discussing the physiological make-up of a bird, it is necessary to discuss briefly its mental capacity. Herrick ( 1924) states, “It is everywhere recognized that birds possess highly complex instinctive endowments and that their intelligence is very limited.” Van Tyne and Berger (1959) cor- roborate this statement of Herrick. A limited knowledge and reasoning ability affects everything the bird does. When a strange situation is forced upon it, the bird cannot rationalize the situation, but employs the trial and error method. If given enough practice the bird will eventually learn to solve the task. However, once the task is learned and time interval between practices increased, the memory or knowledge of the situation fades and the bird again resorts to trial and error. When the bird is confronted with natural phenomena, it has an adequate mental capability and can adapt itself to meet the changing situation. How- ever, in dealing with unnatural phenomena (i.e. outside electrical lighting, buildings, TV towers, etc.,) the bird does not have the necessary knowledge or the ability to reason. Also these phenomena erupt at a very alarming rate which tend to preclude adaptions. Therefore, the bird with a knowledge of unnatural phenomena or the ability to recognize them, must have a greater facility for reasoning that the present class of Aves, or be hatched in an area where such phenomena are a part of its natural environment ( urban dwellers. ) Perhaps the bird is compensated for a lack of mental ability by a highly attuned reflex action and acute visual capability. Mann and Pirie state, “Small birds, hunting for minute seeds and insects also require good eyesight, and it is obvious, both from their way of life and from the structure of their eyes and brains that birds rely on sight more than any other sense except the proprioceptive one.” It would seem that the eye of the bird is its basic source of knowledge and the basic sensory organ for its actions. Van Tyne and Berger (1959 ) classify the eyes as the most important sensing organ of the bird. The bird is more capable of acute night vision than humans. The author has seen innumerable birds fly out of the beams of headlights and flashlights into the dark. None have ever been seen to crash into any obstruction. It cannot be suggested that the birds are blinded in one eye. If this were the case, the birds would normally maintain a circular flight path hut they definitely do not. Therefore, it can he accepted that natural darkness is a phenomenon that the bird is familiar with. 408 THE WILSON BULLETIN December 1979 Vol. 82, No. 4 Other sensory organs of bird may be used for spatial orientation. The visceral senses of a bird may be used in flying. A glimpse at a bird, while it is flying, will reveal the silhouette of a high-wing monoplane. The high mounted wing gives a stabilizing advantage through pendulum effect, with the viscera positioned at the bottom of the pendulum. An appreciation of a roll around the bird’s fore and aft axis could be realized through its visceral senses. Suppose the bird were flying on a straight course at a constant 45 degrees to the horizontal. The heavier parts of the viscera would tend to realign themselves with gravity. While the movement of the viscera would be slight, it be would appreciated the same as the dispersement of the human viscera on laying down. The realignment of the viscera would be sufficient for the bird to realize that its body is not aligned with gravity. Also, if the bird in level flight suddenly tried a loop or a bunt, the viscera through its slight movement would give an indication of positive or negative “G” loading. Therefore the viscera of a bird can appreciate both accelerations and gravity. A second means of appreciating a bank would be through the “tactile” senses of the feathers. The weight of a bird while in a bank is still acting through gravity but the lift, generated by the wings, is acting at right angles to the bird’s lateral axis. Because the lift no longer balances the weight, the bird will tend to side-slip. The side-slip induces an increased airflow over the lower wing as the airflow is now coming from ahead and below, instead of a straight ahead. The change in direction of airflow causes an increased air pressure against the downward side of the bird’s body. The body, be- cause of its inclination, produces a blanking effect against the inclined air- flow over the upper wing. The blanking effect produces a decreased lift on tbe upper wing, and a decreased air pressure against the feathers on the upper side of the body. Thus the bird, by “tactile” sensory perception, can evaluate a comparison of airflow pressures and appreciate tbe fact that it is flying on an inclined plane. Did Hochbaum (1955 ) recognize the “tactile” and visceral senses in his statement; “Not only is the blindfolded bird able to balance its head when held in the hand, but when it is cast into tbe air, body and head quickly assume the posture of flight. Like a cat falling with its feet to the ground, the blindfolded bird quickly adjusts to its belly-down flight attitude when cast aloft.” In the air the bird senses only differential air pressure on its various surfaces and the “G” forces on its viscera. Therefore, the bird, conscious of not sensing its weight on its lower body surfaces against land or water, can only assume that it is in the air. Consequently, it will quickly assume the position of flight, whether right side up or not is of no great importance. The pendulum effect of the body, particularly with a reversed center of gravity, will quickly return the bird to its normal flight attitude. A. D. Herbert SPATIAL DISORIENTATION 409 Also the visceral senses will indicate an abnormal flight attitude. The “tactile” senses of the feathers will also inform the bird of an abnormal attitude. Thus the bird has many stimuli, other then the vestibular apparatus, to re-orient itself. However, the bird was not flying under these circumstances and did not attempt to fly until it was properly oriented. It is suggested that the bird did not balance its head by use of the vestibular apparatus when cast into the air. When cast into the air, the bird was aware of being in the air. Once this knowledge was realized the bird assumed a flying posture. Through the use of its proprioceptive senses, it realized that it had not assumed the proper posture for flight. The relationship of the head, neck and body in a flight posture is a natural or learned posture, thus the bird readily assumes the posture. Mann and Pirie ( 1950 ) state that “the proprioceptive sense is the sense of passive position and the movement of the body in space.” Here again is a relative sensory perception. It is suggested that the proprioceptive per- ception of visceral movement can indicate a bank and be discerned by the bird. However, the proprioceptive sense is much more important. The pro- prioceptive sense is generally accepted as a sense of musculature position. A bird can be conscious of flapping, dragging its feet, bending its neck etc., but the knowledge will in no way affect its spatial orientation at the moment. If we reword Mann and Pirie’s statement to read “the proprioceptive sense is the sense of movement of the body relative to its passive parts,” then the proprioceptive senses may indicate a future spatial orientation. The pro- prioceptive sense is used to control the bird’s posture and govern its airspeed. The vestibular apparatus is conceded to he the main internally-cued organ of orientation. Thus the position of the vestibular apparatus is of great importance. By analogy, the vestibular apparatus is comparable to the gyro-horizon system of an aircraft. This system must be mounted on a fixed platform although the gyro is allowed its own rigidity in space. The aircraft is then allowed to turn around the gyro. Similarly, the vestibular apparatus is mounted in the head. Hochbaum (1955) makes a point of stating that “this steadiness of the head must be of tremendous importance to a bird’s safe arrival from flight, especially in landings made under turbulent conditions or in wooded places. While this stability of the head, regardless of body posture, no doubt serves the visual process during flight, it does not result from the func- tion of the eyes, that is to say, visual orientation alone is not responsible for this balance.” Of course Hochbaum is right; the rigidity of the head is maintained by the vestibular apparatus. The only way the bird can maintain a datum for spatial orientation is to maintain a rigidity of the head since it acts as a mount- ing for the acceleration sensors of the vestibular apparatus. However, the 410 THE WILSON BULLETIN December 1970 Vol. 82, No. i vestibular apparatus has to be confirmed by some means. The only means of doing this is with the eyes and the horizon. The vestibular apparatus is sensitive to accelerations, hut not to a constant acceleration or a fixed position. Hochbaum (1955) states: “The circle was not invariably the pattern in all hooded tests. Some birds adopted flights that varied widely from the circle hut these variations, though individually distinct, always followed a pattern of curves that carried the bird downwind from the starting place.” It would appear that the vestibular apparatus is not sufficiently acute to sense minor discrepancies which can he introduced until the bird has no directional control. Therefore, the eyes of the bird have to establish its initial horizontal orientation and then the vestibular apparatus accepts tbis position as the normal. Any large deviation from this established position is sensed as an acceleration and a deviation from the normal. The bird must constantly recheck its horizontal orientation by visual cues to maintain its spatial orientation. This way the bird maintains its spatial orientation, sensing disturbances to its equilibrium, as far as the head is con- cerned through its vestibular apparatus; and to its body through the “tactile” sense of its feathers and its visceral senses. It changes its body posture relative to its passive head through its proprioceptive senses to correct sensed accelera- tions. Thus the bird uses all of its orientative senses to maintain its spatial orientation; but the basic sensory organs are its eyes — from which it received its initial orientation. FLIGHT CHARACTERISTICS OF THE BIRD Good weather. — Locomotion towards any definite goal is dependent on the stimulus applied by the goal and the spatial orientation of the subject. There- fore, before a bird will fly, it must have a motivating factor, and “know which way is up.” Spatial orientation is necessary even before the bird leaves the ground. No matter how strong the motivating factor is, locomotion in a desired direction is impossible if the bird is not spatially orientated. We have only to watch the pheasant handlers at a dog trial. The handlers get the birds dizzy, or subject to spatial disorientation, and the birds sit where they are put. When the pheasant tries to move, its locomotory organs are not im- paired, hut its guiding senses cannot effectively control the locomotory organs. The visual senses can determine which way to go and the sight of the keeper and the dog impel action; but, because the pheasant is spatially disorientated, the desired action cannot be achieved. Therefore, it would seem that spatial orientation is a prerequisite to any desired locomotion. When the bird is on tbe ground or water, there is an over-abundance of cues for the bird to remain spatially orientated. The weight of the bird itself on its legs gives it an indication of gravitational forces. A glance at the A. D. Kei'bert SPATIAL DISORIENTATION 111 surrounding vegetation will determine the vertical. Even when far removed from land, the bird sitting in the water can determine the vertical hy its weight on the water surface and the visible horizon. The viscera of the bird is in its normal alignment with gravity. The vestibular apparatus has re- mained undisturbed by any excessive acceleration. Thus the bird remains well orientated on its land/water environment. As the bird leaves its land/water environment, it is properly orientated to the vertical and horizontal axes by its gravitational, visceral, vestibular, and visual senses. The first three provide enough stability for the bird to maintain a co-ordinated climb until the transition is made to a horizontal orientation from the vertical orientation. In the air, the bird must have true spatial orientation. It must be able to determine a three-dimensional move ( Eig. 2 ) . The bird must be aware of its altitude, the lateral displacement of its objective (A), the forward or rearward displacement of its objective (B), and the desired route to achieve the objective (C). The bird must also be capable of assessing its position in space relative to fixed objects, to moving objects in space as well as on the ground, and to the horizon. These are the very same problems which con- front the human pilot. On a clear day with good visibility orientation is no particular problem. The bird is flying at the center of its sphere of vision. As Hochbaum (1955) 412 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 states, the horizon is always at eye level. Therefore, the upper half of the bird’s visual sphere will be sky and the lower half ground. During straight and level flight, these hemispheres of ground and sky will be maintained. When the bird banks to turn, it inclines its head and body to the horizon. 4 his action is not to be confused with the body oscillations of an approach to landing. In our case, the downward eye will have an increased amount of ground visible when the upper eye will have less. Thus the bird has a visual comparison to evaluate its spatial position. The accelerations produced by the turn could be sensed by the vestibular apparatus. However, unless the roll or bank was exceedingly abrupt, it is doubtful if the bird would appreciate the vestibular accelerations. As Queeny (1947) demonstrates, ducks use the eyes as the primary organs of orientation even during such maneuvers as a stall-turn. A glance at the horizon confirms the roll or bank. When the bird wishes to resume straight and level flight, it uses its eyes to re-orient its head to the horizon. The proprioceptive senses then realign the body with reference to the head and level flight is resumed. Linally, the vestibular apparatus realigns itself to the primary axes. It is submitted that the vestibular apparatus is not as important as has been previously suggested nor is it exact in its perceptions of accelerations. Ducks can be observed turning their heads through many planes while flying, even to the extent of looking backwards, yet no deviations of their flight paths are noticed. The bird is still able to maintain its flight path by the use of its senses and its latent flying ability. Therefore, it is suggested, the accelerations which affect the vestibular apparatus must be strong enough to affect the other orientation senses, excluding the visual sense. However, any sensual perception of acceleration, whether tactile, visceral or vestibular, is immediately confirmed by the eyes. When the bird encounters turbulence, its whole body and head become subjected to various accelerations. The predominant sense is very difficult to suggest. A straight vertical displacement of the bird would probably be appreciated more by the visceral and tactile senses rather than the vestibular. A horizontal displacement would be appreciated by the visceral and vestibular senses. However, it is unlikely that a straight line displacement would occur because of the bird’s inertia. Therefore, a varying percentage of each sense would be appreciated. However, the bird can still see the horizon, evaluate what is happening and reorient itself accordingly. During its descent for a landing, the bird must reverse the previous transition of orientation cues. Initially the bird selects a general landing area while using a horizontal orientation datum. The bird must continuously assess its groundspeed and track to the landing points; its flight course and the wind velocity; the rate of descent and airspeed; the approach angle A. D. Herbert SPATIAL DISORIENTATION 41.3 to the landing area and any obstructions; and the changing distance to the landing point. The bird must also maintain an awareness of its spatial orientation ( relative to the horizon ) and its postural position. As has been previously explained the postural position is determined through the proprioceptive senses. The postural position of the bird is the basic determinant of the bird’s airspeed. Therefore, it must have positive knowledge of its body position. However, its airspeed is sensed by the tactile acuteness of the feathers and the alula. Van Tyne and Berger (1959) state, “The presence of wing slots increases lift which is needed especially at the take-off. The alula functions as a wing slot when it is drawn forward away from the rest of the hand.” By inference a bird needs a high lift capacity when flying at low airspeeds. Therefore, the bird’s airspeed is determined by its proprioceptive senses and the tactile senses of the feathers. The vestibular apparatus is needed to maintain a proper vertical and horizontal orientation of the head. Only by maintaining a constantly level head can the changing angles and vectors of a descent and landing be as- sessed. The bird is also making a visual transition of horizontally orientated relatively high level flight to a vertically orientated low level flight. How- ever, the transition is being done in much less time and with a greater need for accuracy. The bird subconsciously appreciates a general vertical orienta- tion from the overhead light, but this is not accurate enough for landing. The bird’s eyes can give the vestibular apparatus a datum, hut not continuous information. Therefore, to maintain its spatial orientation, the bird must maintain its head in a fixed position relative to the horizon which the vestibular apparatus is trying to do. The eyes are busily engaged in assessing the vectors of a descent and landing, since these factors can only be determined through the bird’s eyes. It has no other way of gaining the required information for a successful landing. In summary, flying during good weather is relatively easy for the l)ird. The bird is flying at the center of its visual sphere. By using its eyes the bird can visually assess its attitude relative to the horizon. However, the bird can assess only the position of its head. The postural position and wing position must he done through its proprioceptive senses. Accelerations from outside the body are sensed through the viscera, vestibular apparatus, and the tactile senses of the feathers. The airspeed of the bird is sensed by the tactile sense and the alula, hut it is governed by the posture of the bird. The steadiness of the head is imperative on landing. Only if the head is main- tained in a fixed plane can the eyes give a proper recording of the changing vectors. The vestibular apparatus must he able to maintain a rigidity in space of the head comparable to a gyro. However, the regulatory organs for 414 THE WILSON BULLETIN Deccmher 1970 Vol. 82, No. 4 ; I I I I I I I ihe vestibular apparatus are the eyes, as only the eyes can give instant recosnition of the vertical and horizontal axes. Poor iveather. — The weather situations which bring about restricted visibili- ties are low ceilings with precipitation, and/or fog. Llight through restricted visibilities from any cause is exactly the same, except that fog may arrest any hut purely local movement. The bird is forced to reduce its flight altitude to that which will afford a safe passage. As many a marsh hunter has experienced, ducks will and do move in the fog, hut at very low altitudes. The visible horizon is the restrictive factor forcing the bird to fly low. Whereas in good visibility the bird was flying at the center of its visual sphere, in poor visibility it is flying at the apex of its visual cone. The periphery of the cone’s base is the radial horizontal visibility, or less. The altitude of the bird, or the apex of the cone is de- A. D. Herbert SPATIAL DISORIENTATION 415 termined by the radial visibility, the bird’s speed and its reaction time, not by the vertical visibility. As altitude is increased, the horizonal visibility de- creases until the bird can only see straight down. As the bird requires initiating cues for the vestibular apparatus it must fly at an altitude where it can see a horizon. Therefore an acute cone must be changed to a cone with the largest base. Consequently the bird will fly at a much lower altitude in order to extend its visible horizon (Fig. 3). Also by flying at a low altitude the bird has extended its required reaction time for its airspeed by increasing the visibility distance. It must be remembered that the bird may be theoretically still flying within its sphere of vision limited by the obscuring medium; but this is of no consequence unless some- thing is visible within the sphere. The method of spatial orientation used by a bird flying through adverse weather is exactly the same as when flying in good weather. The visual sense must provide the datum for spatial orientation. The vestibular ap- paratus accepts these axes as the datum and senses any deviation. However, the bird sets weather minima below which it will not fly because it cannot maintain its spatial orientation, and its reaction time at its airspeed is too great for a particular visibility. Nocturnal flight is conducted in exactly the same manner as diurnal flight. The weather will have exactly the same effect on the bird’s flight during nocturnal periods as diurnal periods. The bird is faced with exactly the same problems, but they may be of greater intensity because of darkness. However, as Hochbaum quotes Lincoln (1950) “the nights are rarely so dark that all terrestrial objects are totally obscured, and such features as coastlines and rivers are just those that are most likely to be seen in the faintest light, particularly by the acute vision of the bird and its aerial point of observation.” Thus darkness is not an inhibiting factor to nocturnal travel but may be a restrictive factor as far as altitude is concerned. ANALYSIS OF CASES Let us now apply our knowledge of how a bird flies to the cases previously described when the birds were flying under conditions of poor visibilities and low ceilings and unnatural phenomena. Until reaching the lighted areas, the birds had been flying over the open countryside at an altitude high enough to maintain adequate visual cues for spatial orientation, yet below their normal cruising altitudes in clear weather. Suddenly they were sur- rounded by lights of various and varying intensities with shadows at a variety of angles. The birds used their knowledge in an attempt to orient themselves and escape from the area. However, their knowledge was of natural, rather than unnatural, phenomena. Such reorientation, based on natural phenomena applied to unnatural phenomena is the initial step toward spatial disorientation. 416 THE WILSON BULLETIN December 1970 Vol. 82, No. T Consider the first situation — the Blackburnian Warblers flying into the light and shadow. The shadow line from the flood lights extends out from the building at an angle of thirty degrees below the horizontal. Prior to entering the area the bird had been using the natural shadows, the land shadow against the horizon, for spatial orientation. As it approaches the area, the lights are above or level with it and to one side of it. There is also reflected light from the adjacent buildings. The closer the bird approaches the lights, the more defined the shadows become and the natural horizon becomes more diffuse until it fades completely. Having lost its natural datum for orientation, the bird seeks new visual cues in the lights and shadows of the artificial situation. What the bird sees it accepts as true because of its lack of knowledge. Accepting erroneous visual cues, the bird re-orients itself to the false horizon. Having rolled to a plane inclined from the true horizontal but parallel to the false horizon, the bird attempts to fly straight and level. The vestibular apparatus appreciated and accepted the roll to the new position. However, the roll was appreciated as an acceleration to a new position rather than a return to equilibrium. The visceral senses also show a displacement from the true horizontal or vertical. Now the bird has dis- crepant cues (visual and sensory) to the horizontal. As the bird maintains the bank it will start a descendina; turn. The “tactile” senses of the feathers and the pendulum effect of the bird’s body inform it of an incipient spiral dive. As the bird’s brain notes the incipient dive, it starts to take normal corrective reactions; but these reactions do not achieve the anticipated results because the corrective action is to a false horizon. These correct results, according to the inclined plane, promote further accelerations which confuse the bird. The bird is attempting to correlate compounding sensual information with visual inform.ation. As will be noted, it is the bird’s inability to analyse the visual and sensory cues that is the basic cause of spatial disorientation. Unfortunately spatial disorientation, when flying, is a phenomenon which occurs with lightning rapidity. In the case of Baldwin’s observations of the bird flying directly into the lights, the situation is slightly different. The situation is a case of straight loss of visual cues. This situation is analogous to the poacher with his strong light after pheasant. The pheasant remains perched in the light without moving, not because of hypnosis, but because it has lost its visual cues to spatial orientation. The proprioceptive, vestibular, and visceral senses maintain the pheasant’s balance on the tree, but it is afraid to fly because it cannot resolve the problem of spatial orientation without visual cues. The light has obliterated any background and consequently all the pheasant can see is the light. This is exactly what happens when the bird flies into the lights. It loses its visual cues to the horizontal. The vestibular apparatus can measure A. D. Herbert SPATIAL DISORIENTATION TI7 only accelerations and when they stop, hut not when the bird returns to the normal position. Consequently, the bird is comparing sensory information with visual information and is unable to resolve the problem because there is no visual information. In this particular case it is quite conceivable that spatial disorientation does not occur until such times as the bird takes evasive or corrective action. At that time the vestibular apparatus would he subjeeted to accelerations. Once the accelerations are reduced to zero the bird has no indication of the true horizontal except tactile and visceral senses, and these senses are not accurate enough for flying. Therefore, with an absence of visual cues, the bird has no means of orienting itself and is forced to accept any cues it can find. If the lights or the shadows are used as a datum, spatial disorientation is the inevitable result. The refracted and reflected electric light in precipitation produces the same result. With the sun or moon shining on a reflected surface, the bird can maintain a constant bearing or azimuth and angular altitude to the reflected image. (Celestial light is, for practical purposes, made up of parallel rays). However, when the bird attempts this normal reaction with the unnatural light, it immediately begins to fly a curve, because the unnatural light is dis- seminated radially from its source. Thus the visual senses appreeiate a fixed horizon, but the sensory apparatuses appreciate the accelerations of the arc of the flight path. There is a tendency for the rate of turn to increase thereby compounding the accelerations. As the rate of turn increases, there is a change in the angular altitude of the light. To offset the change the bird would have to change its degree of roll thereby producing further accelera- tions. Now the bird has a visual cue to the horizontal and discrepant sensory cues. Since it cannot resolve the information, it becomes spatially dis- orientated. The refracted and reflected light in precipitation produce the same results through exactly the same causes. Because it has a very localized source this light is not directly overhead, hut at any angle between the bird and the source of light. This angle is dependent on the proximity of the bird to the source of light. Whether the bird is misled into reasoning that the light is the Aurora or halation from high clouds, is unknown. The bird, however, accepts the light as the true horizon and reorients itself accordingly. Ihe sensory ap- paratus detects the accelerations. As soon as a comparison of visual and sensory cues is effected, spatial disorientation is imminent. An analysis of the weather conditions in Stoddard’s report (1962) will show that on all of the twenty-four occasions, parts of the TV tower were obscured on thirteen nights, the tower was clear on nine nights but there was precipitation on five of these nights. There is no comment on the tower for two occasions. A 418 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 further observation from this report is that an halation ring did develop in low cloud and Scotch mist. In these cases the birds have no horizon as a visual cue to the horizontal whether proceeding to or from the tower and are consequently subjected to spatial disorientation through the same causes as previously illustrated. In the case of airport ceilometers it is evident that the birds are suffering from spatial disorientation, if not complete vertigo, as Laskey (1956) reports “hundreds fluttering high in the beam.” In this situation, the intense lighting is from underneath with darkness on top. The lighting situations is the exact reverse of normal natural light. The ceilometer has obliterated any horizon which the birds had prior to entering the light beam. Therefore the only cues it has are its sensory mechanisms plus its sight. As it attempts to reorient itself by sight, the senses appreciate the deviation from the horizontal and the birds become disoriented. Howell’s (1955) conclusions as to the probable causes of death being an impact with the ground would substantiate an in- ability of the bird to orient itself. It must be noted that very few birds collide in the air and fall to the ground. Birds are capable of regaining flight within a foot vertically of the point of collision. If the bird was not disoriented, no spiral dive and ground impact would occur. As such collisions have been witnessed (Howell, 1955), it must be concluded that the birds were unable to take exasive action, and therefore must have become disorientated. SUMMARY The bird possesses various senses to determine its spatial orientation. Tlie visceral senses give the bird an indication of its body position in space and of the “G” forces acting upon its body during aerial gyrations. The “tactile” senses of the feathers will give the bird an indication of the airflow pressures on either side of its body and wings and allow the bird to sense a bank or a spiral dive. The proprioceptive senses give the bird an indication of its body position relative to its head. The vestibular apparatus can sense the bird’s equilibrium. All of these senses, whether singly or in concert, are not sufficient to maintain a proper spatial orientation. The eyes are the predominant organ of spatial orientation, and for gaining cues to maintain spatial orienta- tion. However, where there are discrepancies between the visual and sensory cues, the visual cues will he accepted rather than the sensory cues. The sensory cues still have sufficient effect to cause a metal block or confusion. The bird has not enough knowledge to analyse the situation and is therefore unable to take any true corrective action. The consequences of the situation is that the bird suffers from spatial disorientation and, in .some cases, complete vertigo. The only conclusion is that birds are susceptible and suffer from spatial disorientation, and further that the causes of spatial disorientation in birds are exactly the same as those which affect the human pilot, namely; fa) the loss of true visual cues to the horizontal; (b) inexperience in flying under such conditions where visual cues are lost; (c) conflict Itetween the sensory and visual cues to orienta- tion; (d) entering an unusual position without being aware of it; plus (e) the lack of knowledge and reasoning ability when dealing with unnatural phenomena. A. D. Herbert SPATIAL DISORIENTATION 419 LITERATURE CITED Aumstkunc, H. G. 1952. Piinciples and Practice of Aviation Medicine. Third Ed., Williams and Williams Co. Baltimore. Baldwin, D. H. 1963. Mass mortality of nocturnal migrants in Ontario. Ontario Field Naturalist, 1:7-15. Clark, B. and A. Graybiel. 1955. Disorientation: A Cause of Pilot Error. Bureau of Medicine and Surgery Research Report No. NM 001 110 100 39, U.S. Naval School of Aviation Medicine. Davis, J. M. 1953. Spatial Disorientation. Proceedings of a Conference on Orientation in Animals, Cornell University, Ithaca, N.Y. 6 and 7 February 1953, Office of Naval Research. Graybiel, A. 1951. Spatial Disorientation in Flight. The Military Surgeon, 108:287- 294. Guyton, A. C. 1961. Textbook of Medical Physiology. W. B. Saunders Co., Phila- delphia. Herrick, C. J. 1924. Neurological Foundation of Animal Behavior. Henry Holt and Co., New York. Hociibalim, H. a. 1955. Travels and Traditions of Waterfowl. Univ. of Minnesota Press, Minneapolis. Howell, J. C. 1955. A comparison of ceilometer mortality at Knoxville and Nashville, Tennessee in 1951 and 1954. Migrant, 26:53-57. Laskey, A. R. 1956. Bird casualties at Smyrna and Nashville ceilometers 1955. Migrant, 27:9. Lincoln, F. C. 1950. Migration of Birds. U.S. Fish and Wildlife Service Circular No. 16:29. Mann, I. and A. Pirie. 1950. The Science of Seeing, (Revised Edition) Penguin Books, Harmondsworth, Middlesex. Queeny, E. M. 1947. Prairie Wings. J. B. Lippincott Co., Philadelphia and New York. Stoddard, H. L. Sr. 1962. Bird Casualties at a Leon County, Florida TV Station, 1955-1%1. Bulletin No. 1, Tall Timbers Research Station, Tallahassee, Florida. Tordoff, H. B. and R. M. Mengel. 1956. Studies of birds killed in nocturnal migra- tion. Univ. of Kansas Puhh, Museum of Natural History, 10:4-7. Van Tyne J. and A. J. Biirger. 1959. Fundamentals of Ornithology. .John Wiley and Sons, Inc., New York. 9023 142 STREET, EDMONTON, ALBERTA, CANADA. 20 .JULY 1969 (ORIGIN.ALLY RECEIVED 29 MARCH 1966.) BREEDING POPULATIONS OE TULE WHITE-ERONTED GEESE IN NORTHWESTERN CANADA Bob Elgas The Tule White-fronted Goose (Anser albifrons gambelli) is one of the least known of the North American wild geese. Available information has been largely limited to observations and collected specimens of wintering birds. The migrational routes are virtually uncharted and breeding areas unknown. The basis for considering gambelli to be a valid subspecies is dis- cussed by Swarth and Bryant (1917), Kuroda (1929), Dalgety and Scott (1948), Todd (1950), and Delacour (1954). Reasons for lack of specific information are the comparative rarity of gambelli, and the fact it is usually confused with the Pacific White-fronted Goose (A. a. frontalis). Because of the mystery surrounding this goose and the fact it had been listed as possibly endangered by the International Union for the Gonservation of Nature and Natural Resources, an expedition to the region of the delta of the MacKenzie River in northwestern Canada was undertaken in 1964. The purpose of the expedition was to try to locate breeding colonies of A. a. gambelli, and to collect live birds for a controlled propagation program. Re- ports that isolated and uninvestigated White-fronted Goose populations nested in this region made it a likely area to search. The expedition, which was originally reported by Elgas (1965), was sponsored and financed by World Wildlife Eund. It was actively supported by the Canadian Wildlife Service, the United States Eish and Wildlife Service and was under the leadership of Bob Elgas and Jack Kiracofe. On 2 July 1964, the expedition arrived at Inuvik, Northwest Territories where a base camp was established. The town of Inuvik is approximately fifty miles east of Aklavik and is on the east side of the MacKenzie River delta. Recognition for his support is given Dick Hill, Manager of the Canadian Wildlife Service Research Laboratory at Inuvik and to Tom Barry, Resident Biologist for the Canadian Wildlife Service. The technical advice and field support given by Mr. Barry was invaluable. On 5 July we made an aerial examination of the Old Crow Elats. Old Crow Flats is in the northern portion of the Yukon Territory, about 150 miles west of Inuvik. It is a plateau 60 to 70 miles in diameter and rather isolated from the northern coastal plain and the MacKenzie delta area by rugged mountain chains. Here is the source of the Old Crow River. The Flats are characterized by thousands of lakes, sloughs, and potholes sur- rounded for the most part by a dense brushy growth. Predominant vegitation 120 Bob Elgas WHITE-FRONTED GEESE NESTING POPULATIONS 421 Table 1 CUARACTEKISTICS OF LiVING Wll ITE-FRONTED GeESE (AnSER ALBIFRONS) CaPTURED IN Northwestern Canada, July 1964 Specimen Number Sex Age When Captured Chord of Wing ( mm ) Exirosed Culmen ( mm ) Tarsus ( mm ) Weight Color Compared with frontalis 1 5 Adult 413 57 77 7 lb 11 OZ Darker brown 2 $ Juvenile 407 56 77 6 lb 9 OZ Intermediate gray-brown 3 $ J uvenile 405 58 78 7 lb 9 OZ Intermediate gray-brown 4 $ Yearling 434 58 80 7 lb 2 OZ Darker brown 5 $ Adult 394 53 78 6 lb 6 OZ Intermediate gray-brown 6 $ Juvenile 410 49 74 5 lb 6 OZ Darker brown 7 5 Juvenile 395 49 77 6 lb 9 OZ Darker brown 8 $ Juvenile 388 54 74 7 lb 2 OZ Darker brown Nos. 1, 3, 6 and 8 measured 15 Februar>' 1968, Nos. 2 i and , 7 measured 26 November 1964, Nos. 4 and 5 measured September 196.5. consists of spruce, willows, and alders with an undergrowth of various grasses, sedges, and mosses. The “hush” formed a heavy overgrowth condition pre- vailing virtually to the shoreline of the numerous lakes and ponds. Open, grassy areas were little evident. Our preliminary search of the Flats revealed few geese, none of which appeared to be breeding birds. We then flew to the village of Old Crow, where we consulted with Charlie Peter Charlie, head man of the village and chief of the Loucheaux Indians. Charlie had spent his entire life in the area and was perhaps more familiar with Old Crow Flats, and its wildlife, than any living man. On a map furnished by the Royal Canadian Mounted Police, Charlie indicated a specific location, in the southwest portion of the Flats, known to his people as Dry Lake, and said we could expect to find breeding White-fronted Geese there. We immediately flew to the suggested location, landed, and spent considerable time in searching the area. While adult and young (breeding) geese were in evidence the heavy brush made observation difficult. We were eventually successful in capturing two downy young Whitefronts, approximately a week old. Unfortunately, a close study of parent birds was not possible since they were not yet in the molt. In flight, however, they appeared larger and darker than examples of frontalis with which we were familiar in Alaska. The two downies were darker than any White-fronted goslings I had previously seen. Their distinction from 422 THE WILSON BULLETIN Deccinl^cr 1970 Vol. 82, No. 4 A. a. frontalis goslings was similar to that of downy Branta canadensis oc- cidentalis as compared to downy B. c. inofjitti. These two goslings, both of which were females, were kept alive for propagation and subsequent study. They are numbers 6 and 7, Table 1. On 6 July a flight was made from Inuvik eastward to the Kugalik River, about 80 miles distant, where a single White-fronted gosling was taken. This gosling again proved to be a female and was retained for the propagation program (No. 8, Table 1). It was interesting to note that this gosling, which was approximately a week old, was following an adult Lesser Canada Goose [Branta canadensis parvipes) and its own parents were not seen. We could hut speculate as to the reason, but presumably the gosling had become separated from its own parents and had been adopted by the Lesser Canada. The Kugalik River area was much different from the Old Crow Llats in that a more open and grassier condition existed. Here the willow and alder scrub was replaced by large grassy areas and the contrast between the two conditions was striking. Our time was limited and our visit to the Kugalik was brief, so that our examination of the area was quite inadequate. Presumably other breeding White-fronted Geese may have been utilizing the area and further observation would have been desirable. It was noted that the natal down of the Kugalik River gosling was characterized by the same dark color as the two taken the day before at Old Crow Llats. Downy young Whitefronts reported by Hanson, Queneau, and Scott (1956) from the Perry River, N. W. T. were described as paler rather than darker than frontalis downies, and the adults collected there only slightly larger and darker than Alaska specimens. On 13 July a second trip was made to Old Crow Llats, with headquarters established at the Canadian Wildlife Service cabin at Shafer Lake. This time, banding of White-fronted Geese was undertaken utilizing equipment made available by Tom Barry of the Canadian Wildlife Service. Due to the heavy brush in the Dry Lake area, efforts to hand geese there were unsuccess- ful, although two more downy young were taken (Nos. 2 and 3, Table 1). These two goslings, both males, were approximately two weeks old and were slightly paler than the previously taken young. Inasmuch as the darkness of plumage of adult A. a. ganibelli is considered diagnostically significant ( Lig. 1) it might be well to again note that the five downies taken by the expedition also displayed a darkness when com- pared to downy young A. a. frontalis of similar age. Downies No. 6 and No. 7 (Table 1), collected at Old Crow Llats and downy No. 8 (Table 1) taken on Kugalik River — all females, were approximately one week old when taken. All three were much darker than downy young of frontalis of comparable age. Downies No. 2 and 3 (Table 1), both males, were approximately two Bob Elgas WHITE-FRONTED GEESE NESTING POPUEATIONS 123 Fig. 1. Captive White-fronted Geese. Anser albijrons gambelli in foreground and Anser albijrons frontalis in rear. Both are females. weeks old when taken. Although slightly paler than downies 6, 7 and 8 they were still considerably darker than frontalis downies of similar age. In order to find terrain suitable for trapping geese for banding, it w^as necessary to move to an area to the eastward where a more open condition existed. Here on the larger lakes, flocks of molting geese were congregated and we were able to trap and hand 50 birds. Of these, four have subsequently been recovered, two in Saskatchewan, one in Texas, and one in northcentral Mexico. The geese were captured by utilizing nylon netting which was staked out to form fence-like wings in the water which led into a pound trap on land. The flightless geese were herded into this trap from the water with the float 424 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 plane. In the trapping area, which was roughly 30 miles east of Dry Lake, no breeding adult geese or goslings were encountered. It is possible that the adult birds may have come some distance to molt and may not have been representa- tive of the breeding population of the region. Three of these, two adults. Nos. ] and 5 and a young of the preceding year. No. 4, Table 1, were retained for propagation. At the end of the field work, the eight live geese were transported to the United States where five. Nos. 1, 2, 3, 6 and 8, have been kept for study by Bob Elgas at Big Timber, Montana, and three. Nos. 4, 5 and 7 by Jack Kiracofe at Boiling Springs, Pa. MEASUREMENTS Comparative measurements of Tule and Pacific White-fronted Geese made by David Marshall, Bureau of Sport Fisheries and Wildlife, for field personnel working on the White-fronted Goose study 23 October 1963, from specimens in the Museum of Verte- brate Zoology, University of California, Berkeley, and the California Academy of Sciences, San Francisco: Anser cdbifrons gamhelli Adult male (17 specimens) — Wing (chord), 441^80 (451) mm Exposed culmen, 55-62 (58) mm Adult female (12 specimens) — Wing (chord), 410-441 (432) mm Exposed culmen, 49-59 (55) mm Anser albijrons frontalis Adult male (28 specimens) — Wing (chord), 3914^41 (410) mm Exposed culmen, 44-55 (50) mm Adult female (31 specimens) — Wing ( chord) , 368-419 (400) mm Exposed culmen, 42-51 (47) mm Specimens of Anser a. ganibelli from California in the U. S. National Museum were measured by J. W. Aldrich: Male — Wing 427, 430, 438, and 452 mm Culmen 58, 58, 60, 58 Tarsus 79, 82, 86, 81 Female — Wing 425, 401, 410 mm Culmen 58, 57, 55 Tarsus 79, 79, 76 Adult specimens of Anser a. frontalis from Alaska in U. S. National Museum measured by J. W. Aldrich showed ranges and averages of measurements: Male— (18) Wing 380-425 (404.8) mm (20) Culmen 46.6-56.5 (51.6) mm (20) Tarsus 68-81.5 (75.5) mm Female — (15) Wing 362-405 (387.7) mm (17) Culmen 46-54 (49.7) mm (17) Tarsus 66-75 (71.1) mm Bob Elgas WHITE-FRONTED GEESE NESTING POPULATIONS 425 WEIGHTS OF ADULT Anser albi Irons: After Swarth & Bryant (1917) : (6) male Anser a. gambelli California 7 lb 1 oz-7 lb 8 oz (7 lb 4 oz) (2) male Anser a. frontalis California 5 lb 0 oz-5 lb 6 oz (5 lb 4 oz) (4) female Anser a. gambelli California 5 lb 5 oz-7 lb 0 oz (6 lb 5 oz) (3) female Anser a. frontalis California 3 lb 14 oz-5 lb 8 oz (4 lb 12 oz) Present study: (3) male A. a. gambelli Old Crow Flats, Yukon 7 lb 11 oz; 5 lb 12 oz; 7 lb 9 oz (2) female A. a. gambelli Old Crow Flats, Yukon 5 lb 6 oz; 7 lb 2 oz After Hanson, Queneou and Scott (1956) (2) male A. a. albifrons Perry River, N.W.T. 5 lb 10 oz and 6 lb 8 oz DISCUSSION It is suggested that the downy young taken at Old Grow Flats should he con- sidered as representative of the Old Grow breeding population. The fact that downy young taken at Old Grow Flats did, upon maturing, develop into adults typical of the race A. a. gambelli indicates that, according to observations made by the Elgas-Kiracofe expedition, gambelli must be considered the bleeding population of that area. It should he further noted that the ex- pedition encountered no small pale breeding birds, A. a. frontalis, at Old Grow Flats and the small pale birds encountei'ed were, in each case, nonbreeding molting birds. The mere presence of small pale birds in the breeding area would not necessarily be significant because of the well known tendency of adult nonbreeding geese of one race to wander considerable distances into the breeding grounds of another race. In comparing the weights and measurements of Old Grow Flats and Kugalik River birds ( Table 1 ) with those oi A. a. frontalis and A. a. gambelli obtained from other sources, it is evident that the exposed culmens of these birds fall well within the range for gambelli and closer to the average for this sub- species. Wing (chord) measurements of these birds are small but cannot be satisfactorily compared due to the unusual amount of wear of wing tips which is commonly seen in pen-reared birds. Tarsus measurements are in- conclusive. Weights are within the range of gambelli and greater than those of frontalis. Plumage color is typically darker brown or grey-brown than frontalis, as is characteristic of gambelli, with the exception of birds 2, 3 and 5, which are midway between the two forms. In combined characters, the Old Grow Flats birds seem to he referable to gambelli although they fall in the lower part of the size range of that race as represented by migrant specimens from Galifornia. It is possible the average of Galifornia specimens is not typical of the subspecies but abnormally high due to selection for large birds by the collectors. Further, it should he recalled that the type specimen 426 THE WILSON BULLETIN December 1970 Vol. 82, No. 1 for gambelli came from Texas and the California birds may not be as typical of that race as are those from Old Crow Llats. CONCLUSIONS It is obvious that the Elgas-Kiracofe expedition in 1964 was unable to under- take as thorough an investigation of the White-fronted Goose populations of the MacKenzie River delta area, as would have been desirable. However, information obtained from the small samples collected, which are known to represent the breeding population of that area, indicates that these birds are referable to the subspecies which has been called Anser albifrons gambelli by previous reviewers of the taxonomy of the species. ACKNOWLEDGMENT I wish to acknowledge Dr. John W. Aldrich for his advice on certain points of taxonomy and assistance in preparation of this paper. LITERATURE CITED Delacouu, J. 1954. The waterfowl of the world, Vol. 1. Dalcety, C. T. and Peter Scott. 1948. A new race of the white-fronted goose. Bull. Brit. Ornithol. Club, 68:109-121. Elgas, B. 1965. In search of the tule geese. Modern Game Breeding, 18-23, 55-60, January 1965. Hansen, H. C., P. Queneau, and P. Scott. 1956. The geography, birds and mammals of the Perry River region. Arctic Inst, of N. Amer. Spec. Pubis. No. 3:1-96. Kuroda, N. 1929. On the subspecific validity of Anser gambelli Hartlaub. Condor, 31:172-180. SwARTH, H. S. aNd H. C. Bryant. 1917. A study of the races of the White-fronted Goose (Anser albifrons) occurring in Galifornia. Univ. California PuIjI. Zook, 17:209-222. Todd, W. E. C. 1950. Nomenclature of the White-fronted Goose. Condor, 52:63-68. Irving, L. 1960. Birds of Anaktuvuk Pass, Kobuk, and Old Crow. Ek S. Natl. Mus. Bulk, 217. BIG TIMBER, MONTANA, 20 MAY 1968. WINTER DOMINANCE RELATIONSHIP IN BLACK-CAPPED CHICKADEES Jonathan E. Hartzler Dominance relationships for flocks of birds have been found to vary around two main types. Schelderup-Ebbe recognized individuals within flocks, utilizing marked chickens [Gallus gallus), and discovered they were organized into a “peck-right” unilateral despotism, in which the top bird pecks all, the second dominates all but the top one, and so on; the bottom bird pecks none. Similarly, within flocks of pigeons [Columba livia) Masure and Allee (1934 ) described “peck-dominance” organization which was less rigid than in domestic fowl. Individuals of this species pecked one another; however, the dominant birds pecked more and were pecked less than subordi- nates. Dixon demonstrated peck-right organization within wild flocks of Mountain Chickadees [Parus gambeli) (1965) and Carolina Chickadees [P. carolinensis) (1963 ). Due to conflicting descriptions in the literature, the winter flock behavior of Black-capped Chickadees [P. atricapillus ) is not clear in regard to dominance relationships. Odum (1942) left the status of intermediate members in flocks undetermined, whereas Hamerstrom (1942 ), also working with Blackcaps, found the dominance order of any two birds was clear, but attempts to arrange the flock as a whole failed. Brewer (1961 ) concluded that in small flocks of Carolina and Black-capped Chickadees domi- nance relationships were linear, while in “larger assemblages” deviations from complete linearity occurred. The presence of a dominance hierarchy and the fact that closely related species of the genus Parus (Dixon, 1963; 1965) do show winter range defense, suggest that Black-capped Chickadees may also exhibit this behavior. The present paper reports observations of the social organization of Black-capped Chickadees to help clarify their winter dominance relationships. METHODS To attract chickadees for trapping, banding, and Ijehavioral oljservations, continuously baited feeding stations were set in late December, 1967, in a small river bottom woods of approximately 35 acres located 2.5 miles north of Mankato, Minnesota (Fig. 1). The birds were trapped, fitted with a Fish and Wildlife band, and color-marked (Magic Marker on body plumage and Testor’s airplane dope on retrices). Observations were carried out over the entire study area; however, the Imlk of the data was collected at the five feeders. Criteria for dominance-subordination used in this study were similar to those used by Dixon (1965): (1) successful or unsuccessful attempts at displacement from a perch or food, (2) withdrawal upon detection of an approaching bird, (3) obvious waiting of an individual until another had finished its feeding and departed. Dominance- 427 428 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Fig. 1. Map of the study area showing disposition of winter flock ranges, feeding stations 1-5, and association with plowed fields, Minnesota River, highway, and woods (denoted by diagonal lines). subordination activities were recorded through January and February, 1968. Flock range and composition were ascertained by observations while following the flocks and noting where individuals were seen throughout the study. Attempts were made to arrange individuals within flocks into hierarchies of dominance on the basis of wins and losses at the feeders. If any two individuals next to each other in a hierarchy had no observed dominance encounters with each other, they were arranged randomly with respect to each other, such as BGT and RRR (Table 1). Additional observations were carried out through March and April to ascertain sex and breeding territories. RESULTS AND DISCUSSION Flock composition, and winter range. — Indications were that the local chick- adee population and flock composition varied during the winter. After the initial capture of 20 chickadees from 30 December 1967 to 4 January 1968, no new birds were observed until 29 January when 18 new birds were captured during February. Of the total 38 captured, 7 early captures were members of the home flock; the 18 new captures constituted the south flock, and the remainder were members of the north and island flocks (Fig. 1). The most extensively studied of these flocks, the home flock, occupied a well-defined J(»nalhan E. Hartzler CHICKADEE DOMINANCE REEATIONSHIPS 429 winter range of approximately 35 acres. Because of much wandering and trespassing, the winter ranges of the other 3 flocks were not clearly defined. The home flock was almost always in their winter range and generally traveled together, although not all members were always present at any given time. The other flocks, however, were less cohesive and the composition varied so much that much of the time they could not be identified and followed as flocks. Members of other flocks frec|uently visited the home flock range, espe- cially near the river boundary, and members of the home flock were observed on several occasions to fly across to the island. Odum’s ( 1942 ) flocks in New York varied in composition, and his average flock range was 35 acres. In Massachusetts, the winter flock range was established in the fall and retained w4th only minor changes until spring dispersal (Wallace, 1941). In Utah, the Black-capped Chickadee (M. Erydendall, pers. comm.) occupied re- stricted flock territories of 6 to 8 acres, and the flock composition was stable throughout the winter. It is apparent that flock behavior in Black- capped Chickadees varies. Brewer (1961) emphasized that flock size, as well as degree of constancy of flock composition in chickadees, varies with many factors both of the birds themselves and of the environment. Intraflock dominance. — Enough gregariousness was present in Black-capped Chickadees so that organized flocking occurred. However, individuals were antagonistic toward each other in that no two birds were ever observed to tolerate each other at close proximity, such as at a 4 X 8 inch feeder. Intra- flock dominance was characterized by a minimum of display, such as postur- ing, vocalizing, or actual comhat; thus, subordinate individuals readily gave up feeders upon approach of a dominant bird and would not challenge dominants at the feeders. During this study a subordinate individual w^as often observed to withdraw from a feeder when a dominant individual was approaching on the wing at a distance of 10 to 15 yards. In order for such coordination to exist between dominant and subordinate flock-mates. Black- caps must be able to efficiently recognize other individuals. Similar observa- tions were reported by Dixon (1965) in the intraflock dominance contests of Mountain Chickadees. Within the home flock, individuals were organized into a peck-right dominance hierarchy which held wherever the flock traveled within the flock range. Table 1 summarizes the dominance-subordination data for the members of the home flock. These observations are from five different locations inside the home flock range (feeding stations 1-5, Eig. 1); thus a true peck-right dominance hierarchy existed for this flock of birds because the hierarchy was constant at different locations. Mountain Chickadees (Dixon, 1965) and Carolina Chickadees (Dixon, 1963) also showed a peck-right winter flock organization, but Great Tits (Pants major) (Brian, 1949) and Blue Tits 430 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 1 Dominance-subordination Relationships of the Home Flock. Data from all five feeding stations, 2 January to 29 February, 35 days of observation. Winners read horizontally. RRR YTT GC BGT RRF BRF RC Total Wins % Wins 5 RRR — 5 18 8 15 11 7 64 96 YTT _ — 4 ~ 9 6 9 28 85 GC — — — 2 2 6 1 11 31 9 BGT 3 - - — - 3 2 8 44 $ RRF - - - - — 12 6 18 40 BRF - - 2 - 1 ■ — 6 9 20 9 RC - - - - - - — 0 0 (7*. caeruleiis) ( Colquhoun, 1942) both showed social rank in winter flocks dependent on the distance from subsequent breeding territories. Marler (1955) would describe these latter two species as exhibiting peck-dominance because of the effect of location on the dominance outcome. It is necessary that observations from several different locations be used to establish a peck- right hierarchy, because data from a site-dependent, peck-dominant hierarchy, such as in Great Tits, appears to he peck-right if collected from one location only. Lew reversals in the hierarchy occurred during observation (Table 1). On 29 Lebruary, the last day the home flock was observed together, the alpha male, RRR, three times allowed BGT to feed while he waited at station 1. However, RRR dominated BGT twice on that day at the same station, and six times prior to this at various stations. Proof of sex was not obtained, hut RRR appeared to be a male from his dominance position and role in territory defense in April, 1968, and BGT was his mate (to he further dis- cussed in the spring dispersal section). It appeared that during the winter the male of a pair (RRR) dominated the female (BGT) until near spring dispersal, when he may wait for her to feed. Odum (1942) reports that feeding of the female by the male does not appear in courtship, but occurs later, particularly in incubation. So these reversals of RRR and his mate may he the closest thing to feeding during the early stages of pairing which the Blackcap shows. Other reversals in the home flock were cases of unexplainable revolts on the part of BRL. Hammerstrom (1942) recorded only one reversal in 76 fights among Blackcaps. However, only actual fights were used as dominance criteria, and the flock as a whole was not arranged into a dominance hierarchy. Odum ( 1942) called the intermediate birds in his hierarchies “peck-dominant” Jonatiiau E. Hartzlcr CHICKADEE DOMINANCE RELATIONSHIPS 431 because of frequent reversals. The only reversals reported in Carolina or Mountain Chickadees by Dixon (1963, 1965) were the temporary loss of status by mates of alpha males when the males were removed. My study did not indicate high status for the mate of the alpha male; she ranked fourth out of seven. No attempt to remove the alpha male was made in this study. Spring dispejsal. — After traveling together as a fairly cohesive unit during January and Eehruary, 1968, the home flock was observed broken up into pairs on 6 March and subsequently never seen again as a unit. Four members of the home flock, RRR, BGT, RRF, and RC, were observed as pairs in the east half of the home flock woods. RRF and RC, fifth and last in the home flock hierarchy respectively, occupied the middle portion of the home flock range next to the river and were observed as a pair 15 March, 2 April, and 21 April. When seen together RRF appeared to be the male from his singing and general aggressiveness. Dixon found alpha males, but no individuals low in the hierarchies, of most winter flocks remained to establish pair territories within the flock range in Carolina Chickadees (1963) and Mountain Chickadees (1965). RRR and BGT, first and fourth in the home flock hierarchy respectively, occupied the central portion of the home flock woods and were observed together 6 March and 21 April. On 21 April, while their mates fed nearby in the home flock woods, RRR actively directed the “p/zoebe” territorial song of the Blackcap at RRF, who actively replied. This singing duel lasted for nearly 30 minutes, and is further evidence that RRR and RRF were males and RC and BGT females. Of the other home flock members only YTT, second in the hierarchy, was subsequently observed after dispersal, on 6 March and 15 March, foraging in the strip of trees beside the highway, approximately 300 yards from the home flock winter range. Interflock dominance. — Dominance between flocks of Black-capped Chicka- dees was less well defined than that within the home flock. Members of the home flock did not challenge trespassing birds on the border of the home flock range, except RRR and RRF, both thought to be males who were known to have remained in the winter range and established territories. These two males actively challenged two dominant birds from the south flock. Late in February, RRR and RRF went through extensive posturing, calling, chasing, and actual physical combat with two intruders on the border between the home flock and south flock winter ranges at feeder 1 (Fig. 1). In these encounters RRR and RRF of the home flock were dominant in all instances except one, when, after a long display and chase, RRR was displaced by a dominant individual of the south flock. These interflock displays were much more violent than the few timid challenges within the home flock. The other members of the home flock were dominant over intruders at the feeders (Table 2) but did not actively challenge or chase any of them. Similar 432 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 2 Interflock Dominance-subordination encounters of the Home Flock. Data from all intruders over the entire home flock range from 2 January to 29 February, 35 days of observation. Wins Losses Total Per cent Won $ RRR 28 1 29 97 YTT 22 0 22 100 GC 15 1 16 94 $ BGT 1 2 3 33 S RRF 25 1 26 96 BRF 9 4 13 69 $ RC 20 5 25 80 Total 120 14 134 90 relationships were found between intraflock and interflock encounters in Mountain Chickadees (Dixon, 1965). One important difference does exist, however: in the Mountain Chickadee the alpha males directed hostilities against all intruders, while in this study the Blackcap alpha male actively challenged only dominant intruders, even though he dominated all at the feeders. An even better perceptual system than in intraflock dominance is indicated here, for all home flock members recognized intruders and RRR and RRL recognized the dominant individuals of the south flock. The birds of the south flock singled out for attack by RRR and RRL were ALLG and WTBS, who won 75 and 100 per cent, respectively, of their dominance encounters with flock mates. This evidence strongly suggests that ALLG and WTBS were dominant members of the south flock (compare with percentage won of RRR and YTT of the home flock. Table 1 ) . Because of the south flock’s late appearance and my difficulty in establishing feeding stations in the south flock woods, sufficient data to arrange the entire flock into a hierarchy are lacking. I suspect that ALLG and WTBS were males and that they established or intended to establish pair territories in the general area of feeder 1, but attempts to locate these and to ascertain their sex failed. WTBS was seen after spring dispersal near station 1 on 6 March 1968. Because active conflict and interflock dominance appeared to be related to the location of the subsequent breeding territories of the home flock males. Blackcap interflock behavior fits the concept of peck-dominance as modified by Allee (1942 ) to include the location of the contests. Therefore, Black-capped Chickadees had a system of peck-dominance organization work- ing between flocks, simultaneously with a peck-right system within the flock, similar to the Mountain Chickadee (Dixon, 1965). Jonallian E. HarUler CHICKADEE DOMINANCE RELATIONSHIPS 433 With the exception of BGT, the individuals who remained in the winter flock range to establish breeding territories ( RRR, RRE, RC ) had unusually high numbers of interflock encounters. The males of this group also won more interflock encounters than any other home flock members. Members of the home flock were in general dominant over trespassing birds, winning 90 per cent of all interflock contests observed within the home flock range. Thus all the members of the home flock, whether high or low in the hierarchy, whether or not they established later pair territories within the home flock range, had the advantage of precedence to food over intruders within the home flock range. The dominance position of an individual within the home flock had an important relationship to its success in interflock contests (Table 2 ). The alpha male, RRR, had and won more interflock contests than any other bird, while the bottom two birds, RC and BRE, lost more contests than any other birds. However, they still won most encounters at the feeders. The per cent won column of Table 2 shows a trend of decrease down the hierarchy; the average of the top three individuals is 97 per cent while the average of the bottom three is 82 per cent. Because only RRR and RRE, and not the flock as a whole, actively excluded trespassers from the flock boundary, the concept of a “winter flock territory” does not apply to this species. Odum (1942) uses winter flock range instead, and Dixon (1963) found that Carolina Chickadees did not exhibit group territories, because only the alpha male defended the area against males of other flocks. Thus a “group territory” existed only for the dominant males who remained to nest in the winter range. The remainder joined the dominant males to form the winter flock, but played no noticeable part in winter range defense. SUMMARY The winter flock behavior of Black-capped Chickadees was studied in relationship to their dominance hierarchy. Within the home flock a peck-right dominance hierarchy was described, but between flocks dominance relationships were better characterized as peck-dominant. The intolerance of the home flock males to dominant members of other flocks was associated with the location of subsequent breeding territories within the winter range, while the intraflock dominance hierarchy held wherever the flock traveled. Dominance-subordination within the home flock involved little calling, posturing, and no chasing, while interflock encounters did when they involved dominant males. Observations suggested that individual variability is important in interpreting the behavior of this species. One flock of seven chickadees, the home flock, moved aiound its winter range with little internal conflict; trespass of subordinate members of neighhoi- ing flocks was common, hut the visiting lairds were sul)ordinant to the lesidents at the feeders. Dominant individuals of other flocks did not trespass deep into the home flock winter range, but remained on the periphery where they were challenged 1)> dominant 434 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 home flock males. The surrounding flocks varied in size from 4 to 18 individuals, were less cohesive, and eould not be located at any specified time as could the home flock. ACKNOWLEDGMENTS I wish to acknowledge the stimulating guidance of my advisor. Dr. M. J. Frydendall, in assisting me throughout the study, which was done in partial fulfillment of the degree of Master of Arts at Mankato State College. Thanks again goes to my advisor and to Dr. W. Brown of the University of Montana for critical reading and help in preparing the manuscript. LITERATURE CITED Allee, W. C. 1942. Social dominance and subordination among vertebrates. Biol. Symp., 8:139-162. Brewer, R. 1961. Comparative notes on the life history of the Carolina Chickadee. Wilson Bulk, 73:348-373. Brian, A. D. 1949. Dominance in the Great Tit Parus major. Scottish Naturalist, 61:144-155. CoLQunouN, M. K. 1942. Notes on the social behaviour of Blue Tits. Brit. Birds, 35: 234-240. Dixon, K. L. 1963. Some aspects of social organization in the Carolina Chickadee. Proc. XIII Internatl. Ornithol. Congr., 240-258. Dixon, K. L. 1965. Dominance-subordination relationships in Mountain Chickadees. Condor, 67:291-299. Hammerstrom, F. 1942. Dominance in winter flocks of chickadees. Wilson Bulk, 54: 32-42. Marler, P. 1955. Studies of fighting in Chaffinches (1) Behavior in relation to the social hierarchy. Brit. J. Anim. Behav., 3:111-117. Masure, R. H. and W. C. Allee. 1934. The social order in flocks of the common chicken and pigeon. Auk, 51:306-327. Odum, E. P. 1942. Annual cycle of the Black-capped Chickadee-3. Auk, 59:499-531. Wallace, G. J. 1941. Winter studies of color-banded chickadees. Bird-banding, 12: 49-67. DEPARTMENT OF BIOLOGY, MANKATO STATE COLLEGE, MINNESOTA (PRESENT ADDRESS: MONTANA COOPERATIVE WILDLIFE RESEARCH UNIT, UNIVERSITY OF MONTANA, MISSOULA, MONTANA 59801) 27 JANUARY 1969. A COMPARATIVE STUDY OF NESTING FORSTER’S AND BLACK TERNS Robert D. Bergman, Peter Swain, and Milton W. Weller Forster’s Terns {Sterna forsteri) and Black Terns {Chlidonias niger) breed sympatrically in marshes throughout the prairie pothole region of southern Canada and the northern United States (Amer. Ornithol. Union, 1957 ). Nest-sites of Black Terns typically are on low and wet substrates, hut Forster’s Terns use higher and drier sites over water (Weller and Spatcher, 1965 ) . This paper reports an effort to appraise potential competition for nest- sites by determining (1) the precise differences in nest-site utilization, and ( 2 ) the habitat characteristics of the nest locale which may influence site selection. Preliminary observations were made during the summers of 1959 through 1963 in connection with studies of other marsh birds. Detailed investigations were conducted during 1966 to 1968 under sponsorship of the National Science Foundation Undergraduate Research Participation Program at Iowa State University. We are indebted to the following students who assisted in field work: James E. Doidge, Leigh H. Fredrickson, Daniel M. Herrig, and Larry 0. Zach. STUDY AREAS AND METHODS The two major study areas were Rush Lake, south of Ayrshire, Palo Alto County, Iowa, and Dan Green Slough in Clay County, northwest of Ruthven, Iowa. Additional observations were made at Barringer Slough, Smith’s Slough, and the Oppedahl area near Ruthven. Cover maps were prepared annually from measurements made on the ice during the winter and spring, using an aerial photo as a base-map. According to the classification scheme used by Weller and Spatcher (1965) for semi-permanent, fresh-water marshes. Rush Lake was in the “hemi-marsh stage” throughout the study, having nearly equal amounts of open water and cattail (Typha augustifolia) and its hybrids. Muskrats were abundant and were responsible for many openings in the emergent vegetation. There was a slight increase in open water from 1966 to 1968. Dan Green Slough was in the “open-water stage” with only a few clumps of cattail as the result of an “eat-out’ by a rising muskrat population that used most of the available vegetation for food and lodges. Clumps of cattail became progressively reduced throughout the study. During 1966 and especially 1967, there were few muskrats or muskrat lodges at Dan Green Slough. By 1968, the slough was nearly dry and observations were made only from shore. Nests were found by using a canoe. Each nest was numl)ered and marked with a willow pole. The following data were recorded at each nest: (1) cluteh size, (2) height of nest bowl al)0ve water, (3) origin of the nest substrate, (4) composition of nest Journal Paper No. J-6L58 of the Iowa Agriculture and Home Econoinic.s Experiment Station, Ames, Iowa. Project No. 1504. 136 THE WILSON BULLETIN December 1970 Vol. 82, No. 1 Table 1 Frequency of Occurrence OF Nests ON Single Substrates, 1966- -68. No. of Nests per Substrate Mn nf Mean ± S.E. 1 2 3 4 5 Nests Forster’s Tern 73 (86%) 9 ( 11%) 0 1 (1%) 2 (2%) 85 1.2 ± 0.10 Black Tern 197 (100%) 0 0 0 0 197 1.0 ± — substrate, (5) diameter of nest substrate at water level, and (6) species and relative abundance of plants that make up the surrounding vegetation at each nest site. Locations of nests were mapped on cover maps. NESTS AND NEST-SITES Both species of terns sometimes construct a shallow cup-nest with pieces of emergent plants on a substrate of submergent plants or on floating boards. More commonly, however, they use a substrate where little nest construction is necessary but add a few pieces of vegetation to the rim of a natural de- pression. Spacing of nests. — Terns are social birds and usually nest in colonies. Spacing of nests seems to be influenced by the distribution of suitable nest substrates and, presumably, by territorial behavior. We did not study inter- specific behavior, however, and observed no conspicuous interactions. Nests of Black Terns tended to be grouped in certain favorable areas of the marsh, but their nests were dispersed within these areas. In no case was more than one Black Tern nest found on one substrate such as a muskrat lodge (Table 1). Lorster’s Terns were more social, however, and nests com- monly were grouped in “islands” of cattail. Two or more nests occurred on one lodge 14 per cent of the time ( Table 1) and large lodges contained up to 5 nests. Although we did not study tern nests in small marshes, we did note an absence of Lorster’s Terns in such places. Small water areas were used by Black Terns but usually these held only one pair, whereas larger marshes held many pairs (Provost, 1947:500). Substrate utilization. — During the 3 years of intensive study, most nests were on muskrat lodges or feeding platforms (Table 2), but some floating materials were used. Usually they were rootstalks or rafts of emergent vegeta- tion lodged between standing vegetation. At other lakes, we have observed that both species may build nests on floating boards held in place by emergent vegetation. A comparison of nest-sites used at the two lakes indicates the significance of availability of substrates to their use (Table 2). Rush Lake, in the hemi- Bergman, Swain, ami X^'eller FORSTER’S AND BLACK TERN NESTING 437 Table 2 Nest Substrate Utilization. Forster’s Black Substrate Tern Tern A. Rush Lake, 1966-68 Active Muskrat Lodge 58 CO — Inactive Muskrat Lodge 26 (30%) 42 (48%) Muskrat Feeding Platform — 20 (23%) Floating Cattail Rootstalks — 10 (11%) Dead Floating Emergent Vegetation 2 (2%) 16 (18%) Total 86 (100%) 88 (100%) Dan Green Slough, 1966-67 Active Muskrat Lodge 2 (10%) — Inactive Muskrat Lodge 3 (14%) 8 (7%) Muskrat Feeding Platform — 1 (1%) Floating Cattail Rootstalks 12 (57%) 94 (86%) Dead Floating Emergent Vegetation 4 (19%) 6 (6%) Total 21 (100%) 109 (100%) All Nests, 1966-68 Active Muskrat Lodge 60 (56%) — Inactive Muskrat Lodge 29 (27%) 50 (25%) Muskrat Feeding Platform — ■ 21 (11%) Floating Cattail Rootstalks 12 (11%) 104 (53%) Dead Floating Emergent Vegetation 6 (6%) 22 (11%) Total 107 (100%) 197 (100%) marsh condition, had a large muskrat population that provided abundant lodges and feeding platforms on which both Forster’s and Black terns nested. Dan Green Slough, in the “open marsh” condition, had only a small muskrat population, and nest-sites associated with muskrat lodges or feeding plat- forms were relatively scarce compared with Rush Lake. Almost all Forster’s Terns nesting at Rush Lake used large, high muskrat lodges, 68 per cent of which were active (Table 2). Less than 15 lodges were present at Dan Green Slough. However, floating cattail rootstalks were common, and these were used by 57 per cent of the nesting Forsters Terns. In 1960, Rush Lake had a large central open water area with only one large island of cattail. Most of the nests found were in this island although there were numerous muskrat lodges in excellent stands of cattail toward the shore. Of 28 nests located in 1960, 12 (43 per cent) were on floating rootstalks resulting from high water levels; 18 were on muskrat lodges. This colonial 438 THE WILSON BULLETIN December 1970 Vol. 82, No. t Table 3 Height of Nest Bowl Above Water (cm), 1966-68. Forster’s Tern Black Tern Substrate No. of Nests Mean ± S.E. No. of Nests Mean it S.E. Active Muskrat Lodge 58 29.8 ± 2.5 — Inactive Muskrat Lodge 31 15.0 ± 1.8 51 3.4 ± 0.4 Muskrat Feeding Platform — 21 2.8 ± 0.2 Floating Cattail Rootstalks 12 6.0 ± 0.4 102 3.6 ± 0.2 Dead Floating Emergent Vegetation 6 4.7 ± 1.2 23 2.3 ± 0.3 Total 107 21.4 ± 5.3 197 3.3 ± 0.2 behavior reflects another aspect of nesting not well recorded in this study: their sociality seemingly exceeded preference for any specific nest-site. Similar use of available sites was obvious for Black Terns. Seventy per cent of the nests were associated with muskrat structures at Rush Lake, but none were actively being used by muskrats. Most were old and soggy. Evidently because there were no muskrat lodges, eighty-six per cent of the nests at Dan Green Slough were built on floating cattail rootstalks. Substrate size. — A gross comparison of height of the nest bowl above water and substrate diameter of Forster’s and Black Terns (Tables 3 and 4) indicates that Forster’s Terns used larger nest substrates than did Black Terns. Heights of substrates for Forster’s Tern nests averaged 21.4 cm (107 nests) above the water compared with 3.3 cm (197 nests) for Black Tern nests. Forster’s Terns used nest substrates averaging 138.8 cm (94 nests) in diameter compared with 52.2 cm (197 nests) for Black Tern nest substrates. Table 4 Diameter OF Nest Substrate (cm), 1966-68. Forster’s Tern Black Tern Substrate No. of Nests Mean ± S.E. No. of Nests Mean ± S.E. Active Muskrat Lodge 54 171.8 ± 6.0 — Inactive Muskrat Lodge 31 104.1 ± 2.3 52 84.7 ± 5.8 Muskrat Feeding Platform — 20 47.9 ± 6.8 Floating Cattail Rootstalks 4 36.5 ± 3.5 105 41.6 ± 1.4 Dead Floating Emergent Vegetation 5 79.9 ± 2.1 20 27.8 ± 4.3 Total 94 138.8 ± 6.3 197 52.2 ± 2.5 Bergman, Swain, and Weller FORSTER’S AND BLACK TERN NESTING ■139 Differences in site selection can be seen by comparing each nest substrate category between the Eorster’s and Black Tern (Table 3). In 1966, when both species used floating cattail rootstalks on Dan Green Slough, nest bowls of Eorster’s Terns still averaged 6.0 cm (12 nests ) above the water but Black Tern nests averaged only 3.6 cm (48 nests). On inactive muskrat lodges, the average nest bowl height of Eorster’s Terns was 15.0 cm (31 nests), but those of Black Terns averaged 3.4 cm (51 nests) during 1966-1968. The use of active muskrat lodges by Forster’s Terns when Black Terns did not use this substrate probably does not account for all the difference in nest substrate size between the two species (Table 4). Because deserted lodges tend to flatten out from lack of care, these structures often enlarge during deterioration. Flence, one may conclude that Black Terns actually select smaller substrates than do Forster’s Terns and that their use of any wet structure allows greater flexibility in selection of nest-sites. VEGETATION SURROUNDING THE NEST The presence and nature of vegetation surrounding the nest was recorded at each nest-site. At Rush Lake, all Forster’s Tern nests were associated with an open pool of water. Nests usually were on muskrat lodges or on floating- rafts of cattail at the edge of an opening created by muskrats. The higher and drier lodges used by Forster’s Terns appeared unaffected by wave action, and vegetation surrounding the nest seemed of little importance. These lodges form an “island” habitat which, like the large “islands” of cattail, are preferred by Forster’s Terns over other areas. In contrast, Black Tern nests occurred in a variety of vegetative situations from dense stands of cattail to “open water.” In the latter case, their nests were protected from wave action by submergent or emergent plants. A total of 38 Black Tern nests (42 per cent j was found at Rush Lake in open water areas created by muskrats ; the nest substrate in this situation was either a deteriorated muskrat lodge or a muskrat feeding-platform. Floating vegetation (mainly Lemna spp.) occurred around nest-sites of both species but was more abundant around Black Tern nest-sites that were protected from wave action by emergent vegetation. Floating vegetation around nest-sites in open water was relatively light in density due to dispersion by wind and wave action. During this study, Forster’s Tern nests were initiated before floating vegetation became abundant, but Black Tern nests were initiated both before and after tbe development of abundant floating vegetation. GHRONOLOGY OF NESTING During 1966, Forster’s Terns began nesting at Dan Green Slough during the last week of May and at Rush Lake during the first week of June (Fig. 1) . 440 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 (/) I— LU Z m O Z £ O u ^ a FORSTER’S TERN MAY JUNE JULY Fig. 1. Chronology of nest initiation by Forster’s and Black Terns on Rush Lake (1966-68) and Dan Green Slough (1966-67). Hatching was complete at both marshes by the last of June. In 1967 and 1968, the first nests of a Forster’s Tern colony were found during the last week of May at Rush Lake, but all nests were destroyed within two weeks. In 1967, a second colony began nesting during the middle of June, presumably renesting birds of the first group, but all nests again were destroyed before hatching. Black Terns began nesting during the last week of May in 1966 and 1967, and new nests were found continually through the first week of July (Fig. 1). In 1967, heavy rains during the middle of June destroyed a large number Bergman, Swain, and Weller FORSTER’S AND BLACK TERN NESTING 111 Table 5 Nest Success by Nest Substrate, 1966-68. Substrate Successful Unsuccessful Undetermined Forster’s Tern: Active Muskrat Lodge 7 (12%) 49 (84%) 2 (4%) Inactive Muskrat Lodge 3 (10%) 27 (87%) 1 (3%) Muskrat Feeding Platform — — — Floating Cattail Rootstalks 1 (8%) 10 (83%) 1 CO Dead Floating Emergent Vegetation 2 (33%) 4 (67%) — Total 13 (12%) 90 (84%) 4 (4%) Black Tern: Active Muskrat Lodge — — — Inactive Muskrat Lodge 18 (39%) 22 (48%) 6 (13%) Muskrat Feeding Platform 6 (30%) 11 (55%) 3 (15%) Floating Cattail Rootstalks 24 (23%) 76 (72%) 5 (5%) Dead Floating Emergent Vegetation 8 (38%) 12 (57%) 1 (5%) Total 56 (29%) 121 (63%) 15 (8%) of the Black Tern nests and nests found in early July probably were a product of renesting. In 1968, new nests were initiated from 6 June through 22 June. Although Eorster’s Tern nests were initiated only a few days before the first Black Tern nests, the bulk of the colony of Eorster’s Terns initiated nest simultaneously, but new Black Tern nests were initiated throughout June and into July (Eig. 1). CLUTCH SIZE The average clutch size was calculated from the observed clutches only if the egg numbers did not change during one week of observation. Clutch size in both Eorster’s and Black Terns ranged from 1 to 4 eggs. The average clutch size of 92 Forster’s Tern nests was 2.5 (± 0.07) eggs while the average Black Tern clutch was 2.6 [± 0.02) eggs for 151 nests. For both species, clutches of three eggs occurred most frequently (58 per cent of Forster’s and 63 per cent of Black Terns ) , and clutches of 2 eggs were more frequent than clutches of either 1 or 4. INCUBATION PERIOD The incubation period was determined by the time elapsed between the last egg laid and the last egg hatched in a clutch. Because nests usually were visited only once weekly, lelatively few nests provided accurate records of 442 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 incubation periods. Average incubation period for 11 Lorster’s Tern nests was 24.2 days and for 28 Black Tern nests was 21.4 days. NEST SUCCESS Nest sueeess for Lorster’s and Black terns during 1966 to 1968 is compared by nest substrate in Table 5. Nests were considered successful if at least one young hatched and appeared to have survived at the nest-site. This was determined by rechecking the nest weekly after hatching. The fate of some nests was not determined because evidenee of success or failure was not found. Nest success of Lorster’s Tern nests for whieh fate was determined was 12 per cent (13 of 107 nests) compared with 29 per cent of 192 Black Tern nests. Causes of failure of tern nests were attributed to one of the following: wind and wave action, muskrat activity, and predation or intra- specific strife. During June of 1967, heavy rains caused rising water levels and increased muskrat building activity. This evidently caused some de- struction of Lorster’s Tern nests because egg shells were found buried under fresh cattail cuttings. Destroyed eggs were found with small punctures so that some intraspecific strife may have been involved (Bongiorno, 1968), hut the possibility of damage by other birds cannot be ignored (Pessino, 1968). Wind and wave aetion evidently caused most of the failures of Black Tern nests during this study, particularly in open areas where the sparse emergent vegetation was not sufficient to protect the low nests. Unfortunately, there is no obvious pattern of nest success according to nest-site or area. Year by year analyses showed that the best success of Lorster’s Terns was in 1966 when 36 per cent of 46 nests hatched compared with only 4 per cent of 26 nests in 1967 when heavy rains and rising water levels were involved. There also was a suggestion of higher nest success of Lorster’s Terns on active lodges (39 per cent of 18 nests in 1966 ) versus inactive (17 per cent of 12 nests in 1966) or floating cattail rootstalks (8 per eent of 12 nests in 1966) . DISCUSSION The results of this study indicate that when Lorster’s Terns and Black Terns inhabit the same marsh, they seemingly do not compete for nest-sites. The most clear-cut difference was the use of higher and drier nest-sites by Lorster’s Terns while Black Terns utilized lower and wetter sites. Active or recently aetive muskrat lodges were the only nest substrates utilized by the Lorster’s Tern at Rush Lake even though other nest substrates were available. Muskrat lodges provide the highest nest substrate on the marsh and seemed to be preferred, but lower sites were used at Dan Green Slough when muskrat lodges or new, high muskrat lodges were not available. Nevertheless, even these Hcrgman, Swain, and Weller FORSTER’S AND BLACK TERN NESTING 443 nest sites were larger and higher above the water than were Black Tern nest- sites of similar material in the same marsh. Black Terns nested on a variety of nest substrates at Rush Lake but all were low and wet whereas sites used by Forster’s Terns were usually dry. Black Terns apparently preferred emergent vegetation surrounding the nest- site. The density of the vegetation varied, hut this habitat requirement functioned to reduce wind and wave action around the low nest-site. At Rush Lake, Forster’s Tern nest-sites were surrounded by open water, which varied from a small pool created by muskrats to a large open pool. Open w^ater surrounding the nest-site may he a result of Forster’s Tern utilization of muskrat lodges and not necessarily a nest-site stimulus, but they will use very isolated lodges in the middle of open water. Floating vegetation generally w^as more abundant around nest-sites of Black Terns because emergent vegetation reduced wind and wave action, but terns nesting late in the season may select for such areas. Different food habits and methods of feeding also may reduce competition between Forster’s and Black Terns. Martin, Zim and Nelson ( 1951) state that Black Terns are insectivorous, feeding primarily upon mayflies, dragonflies, caddisflies, beetles, and spiders. Forster’s Terns eat fish as their staple food although some aquatic insects may be taken. In a publication on gulls and terns of southern U. S. S. R., Borodulina (1966) classified Black Terns mainly as insectivores that occasionally feed on small fish and tadpoles. He ob- served that Black Terns are especially ichthyophagous in areas where stunned young fish float on the surface. Borodulina also described differences in wing structure and flight behavior that adapts the Black Tern and the black- capped terns of the genus Sterna to their common foods. Possibly the evolution of these terns was one of isolation on small (Black 4'ern) versus large (Forster’s Tern) water areas, which also is related to their insectivorous (Black Tern) versus ichthyophagous (Forster’s Tern) food habits. At the present time they nest in the same marshes w4th little or no obvious competition for nest-sites. SUMMARY Forster’s Terns and Black Terns occur in the same large marshes, l)ut Black Terns nest in small “potholes” in dense vegetation, or more densely vegetated sites on large marshes. During this study. Black Terns used a variety of low and wet nest sul)strates, averaging only 3.3 cm above the water. In contrast, Forster’s Tern nests were placed an average of 21.4 cm above the water and most frequently were placed on large muskrat lodges (83 per cent). Forster’s Tern nests usually were on substrates in or at the edge of open pools of water surrounded by “islands” of cattail hut Black Tern nests occurred in vegetative situations ranging from dense stands of cattail to open water. 114 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 LITERATURE CITED Ameiucan Ornithologists’ Union. 1957. Check-list of North American birds. Fifth ed., Baltimore, Alaryland. Bongiorno, S. F. 1968. Egg puncturing behavior in Laughing Gulls. Auk, 85:697- 699. Borodulina, T. L. 1966. Biology and economic importance of gulls and terns of southern U. S. S. R. water bodies. Israel Program of Scientific Translations Ltd., Jerusalem. Martin, A. C., H. S. Zim, and A. L. Nelson. 1951. American wildlife and plants. Dover Publications, Inc. New York. Pessino, C. M. 1%8. Redwinged Blackbird destroys eggs of Common and Roseate Terns. Auk, 85:513. Provost, M. W. 1947. Nesting of birds in the marshes of northwest Iowa. Amer. Midland Naturalist, 38:485-503. Weller, M. W., and C. E. Spatciter. 1965. Role of habitat in the distribution and abundance of marsh birds. Agriculture and Home Economics Experiment Station Spec. Rpt. 43. Iowa State University, Ames, Iowa. DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, IOWA STATE UNIVERSITY, AMES, IOWA 50010, 12 FEBRUARY 1969. REQUEST FOR INFORMATION As a part of the study on Golden Eagle ecology juveniles of this species were color- marked in southwestern Idaho to determine movement and migration patterns. Marked birds carry a crescent-shaped vinyl band around the humeral area of one or both wings. The colors used were red, pink, yellow, orange, dark green, white, and blue. Information desired includes: color of marker on each wing; the date and location of the sighting; and the observer. Send any information to Michael N. Kochert, Idaho Cooperative Wildlife Research Unit, University of Idaho, Moscow, Idaho 83843. BREEDING BIOLOGY OE AMERICAN COOTS IN IOWA* Leigh H. Fredrickson Although the American Coot [Fulica americana) has been intensively studied by several investigators, many facets of the breeding biology of the species have not been explored. This paper presents observations on the species in Iowa, made during an experimental study of clutch size in the coot (Fredrickson, 1969). Sooter ( 1941 ) conducted intensive studies on coots in northwestern Iowa. Gullion, who studied a small resident population of coots in California, has made the most detailed observations on the breeding cycle. His publications describe voice differences between the sexes (Gullion, 1950), histology and development of the frontal shield ( Gullion, 1951), sex and age determination (Gullion, 1952a), molt (Gullion, 1953a), territorial and courtship activities ( Gullion, 19526 ) , and seasonal variation in interspecific and intraspecific territorial activity (Gullion, 19536). Gullion (1954) summarized his observa- tion on the reproductive cycle of coots in California and compared his findings with information available on other Rallidae. Nest-building, laying, incuba- tion, and hatching were described in detail, but pairing, copulation, and brood-rearing were discussed less thoroughly. STUDY AREA The study area was in northwestern Iowa near Ruthven, a marsh area studied and described in detail by Bennett (1938), Low (1945), and Glover (1956). Coots were studied on three marshes, all of glacial origin but modified so that water levels were controllable. The dominant vegetation was cattail (Typha sp.), which provided the major nesting cover for coots and other species that nest over water. METHODS Nests were located each year by systematically wading or canoeing the marshes. Initiation dates of nests found during laying were calculated by allowing one egg per day. The initiation date was not calculated in nests located during incubation, but embryonic development was ajDpraised by floatation (Westerskov, 1950) or candling (Weller, 1956) as an index to the stage of incuhation. Adult coots were captured for banding and color-marking by using three techniques: nest-trapping, night-lighting, and bait-trapping. Automatic nest-traps similar to those designed by Weller (1957) generally were successful late in the incubation period; occasionally, however, some birds were captured shortly after laying stopped. Some coots were less Itroody than others and avoided entering a trap at any time. Thus, the individual broodiness of a coot determined the success of nest-trapping. * Journal paper No. J-6I63 of the Iowa Agriculture and Home Economics E.xperiment Station, Ames, Iowa. Project 1504. 446 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Night-lighting was effective for capturing nesting birds when the study area and nest locations were well known. The technique worked best on dark nights. Coots were most easily caught with a small-sized dip net made of fine “mist” netting. The birds became entangled in the mist netting which allowed fewer to escape. The maneuverability of the light-weight net in the floating vegetation increased the efficiency of capturing coots. If the exact location of the nest and ramp was known before the night-lighting attempt, the incubating coot could be captured as it left the nest. Gullion’s (1950) method of differentiating sex by vocalizations was used. The higher- pitched call of the male is easily distinguished from the lower-pitched notes of the female. With experience, coots also may he sexed by comparing body size, and shape and size of the frontal shield and hill (Gullion, 1951; Fredrickson, 1968). Adult coots were handed with Fish and Wildlife Service bands and were color-marked in two ways. Each bird was marked with three colored plastic leg bands and a patagial tag, or a nasal saddle, which was visible when the bird was swimming. The patagial tag was similar to one described by Anderson (1963) but was attached to the patagium by a slightly different method. Either a stainless steel welding rod (Uo- inch diameter) or a stainless steel wire was passed through the patagium and the ends flattened or looped beyond plastic washers to hold the tag in position. The tag was made of a double layer of plastic with colors providing individual identification. In 1966 nasal saddles (Sugden and Poston, 1968) were used rather than patagial tags. A saddle-shaped piece of plastic was placed over the culmen in the region of the nares. A Ue-inch diameter stainless steel welding rod was passed through the holes bored in the plastic and through the nares of the bird. The ends of the rod were flattened to hold the saddle in place. Color patterns on the tabs identified individuals. TERRITORIAL BEHAVIOR Gullion (19526) described territorial behavior and reviewed the literature on aggressiveness in coots. My observations support Gullion’s findings. I prefer the term “Chase” over splattering but use the terms “Patrol,” “Charge” and “Paired Display” as described by Gullion. I attempted to determine the intensity of the territorial displays and to determine if displays were used in a particular sequence. Intensity was de- termined by the frequency of display, with displays of lowest intensity oc- curring most often. Figure 1 shows the pattern of displays in 30 complete sequences observed in my study. As many as eight displays have been recorded in a sequence. In 27 of the 30 observations, four or fewer displays were involved in each sequence. In 24 secjuences, the low intensity Patrol was the initial display. In nine of the 24, the intruder retreated and the contest ended. On some oc- casions the initial display was of greater intensity than the Patrol. For ex- ample, both Charging and Chasing were observed as the initial display. Of 19 sequences with more than one display, eight ended in Paired Display, seven ended in Chase, three ended in Patrol and one ended in Charge. Coots usually concluded each display sequence with a quick dive regardless of length or intensity of a sequence. On a few occasions the feathers were COOT BREEDING BIOLOGY 447 Leigli H. Fredrickson DISPLAY PATROL lowest intensity CHARGE CHASE PAIRED DISPLAY FIGHTING FREQUENCY AND POSITION OF DISPLAYS IN A SEQUENCE 8 highest intensity Fig. 1. Frequency of displays observed in territorial activity of the American Coot. straightened by a Shuffle following the dive. This activity did not occur regularly in the sequence, but occurred commonly during feeding or swim- ming. Evidently it arranged the feathers over the entire body. The bird moves upward and forward above the water surface. Simultaneously, the wings are elevated slightly above the body. As the head falls forward, the rear portion of the body rises above the water as if the bird were moving over an obstruction. The breast region makes contact with the water first, and the movement ends when the wings return to the normal position. Several observations of interspecific aggression were made during this study. The degree to which this aggression occurred seemed correlated with the stage of the nesting cycle. Both Mallards (Anas platrhynchos) and Blue- winged Teal iA. discors) were driven from the coots’ territory in May. Neither Ruddy Ducks (Oxyura jamaicensis) nor Redheads (Aythya ameri- cana) were attacked when encountered late in the nesting season. REPRODUCTIVE BIOLOGY Nest and platform construction. — Platform construction is a well-known behavior of nesting coots. Gullion ( 1954) reported that three pairs constructed as many as nine structures associated with nesting during a single season. Other reports on nest construction were by Wetmore (1920) and Walker (1932) and by Kornowski (1957:341-342) for the European Coot (7. atra). In my study, platform building was influenced by the availability of naturally-occurring platforms in the marsh. Coots used muskrat lodges. 448 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Table 1 Use of Cover-type vegetation as Nest Material by IN 1963 through 1966 Coots in the Rutiiven Area Cover-type vegetation Nest material Same as cover-type Cattail Cattail and softstem Cattail and other species Softstem All other sirecies Total Cattail 255 255 44 10 8 3 320 Softstem 16 — — 1 16 — 17 Cattail and softstem 18 — 18 1 8 1 28 Softstem, river bulrush and cattail — — — — 1 — 1 Cattail and river bulrush — — — 3 1 — 4 River bulrush 3 — — — 1 3 3 Hardstem — — — 1 — — 1 Cattail and sedge 1 1 — — — — 2 Willow 1 — — — 1 Burreed — 1 — — — — 1 Cattail and hardstem 1 — — — — — 1 Total 294 258 62 16 35 8 380 feeders, and latrines extensively and built fewer platforms when structures built by muskrats were plentiful. In my study, nestdiuilding was conducted by both sexes of a marked pair. One bird carried material to the nest site while the mate constructed the nest. The construction and collection activities were often interchanged between the sexes. Although coots used structures built by other species for loafing, copulation, and brooding, all 565 nests in my study were built exclusively by coots. Coots are very adaptable and will use a variety of materials in nest con- struction. Possibly dry materials are favored over wet materials, because one pair of marked coots bypassed masses of readily-available floating cattail stalks and traveled to a muskrat lodge to secure dry cattail stalks. Coots did not appear to favor a particular vegetative type for nest materials. The available material was used regardless of species and whether it was cured or green. Cured material was used most commonly. Cover type and nest material were recorded for 380 nests (Table 1). Of this number, 294 were constructed exclusively of material that existed as cover around the nest. Leigli H. Fredrickson COOT BREEDING BIOLOGY 449 Three hundred twenty nests were built in cattail, the most common cover type in these marshes. Of these 320 nests, 255 were built entirely of cattail. Eleven of the nests in cattail were constructed entirely of some other plant species; eight of softstem bulrush {Scirpiis validus), two of softstem bulrush and arrowhead {Sagittaria sp. ) , and one of river bulrush (Scirpus jluvxatihs] . Chronology of nesting. — The chronology for initiation of laying was de- termined in 1964 and 1966 but not in 1965. Dates of initiation were deter- mined either by direct observation or by calculation of the initiation date as described earlier. In 1964, tbe first nests were recorded on 3 May, with tbe first peak of initiation of laying occurring on 11 May (Fig. 2). A second peak of initiation occurred 2 weeks later on 25 May. Althougb coots in California may have two nests each season, no evidence was found that indicated this possibility in Iowa. This second peak may represent renesting or possibly late nests of young birds. 450 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Nest chronology in 1966 differed from that found in 1964. Unusually cold weather in May probably kept the birds in a nonbreeding condition. The first laying occurred 1 week later than was expected. No well-defined peak of initiation of laying occurred during the season, and nest initiation lasted until mid-June (Lig. 2). Some coots did not nest until new vegetation was sufficiently high to provide nest materials and a substrate for attaching nests. On two marsh areas near Ruthven, small flocks of coots had territories located in areas with little or no nesting cover until after late May. Coots in one flock began to nest when a dense bed of sweet flag [Acorus calamus) had grown to a height suitable for nest attachment. Peak of nesting occurred on this area about 25 June, or 6 weeks later than the first peak (11 May). Another flock of coots centered their activity in a sparse stand of cattail that was in poor condition due to a muskrat eat-out and flooding. Twenty- five nests were eventually initiated in the area. But the first egg was laid on 18 May, or 15 days after the first eggs were laid in optimal habitat with taller and more dense vegetation. As the cattail developed, more nests were established, and the peak of initiation of laying occurred on 29 May. No nests were initiated later than 21 June. Twenty-three nests with completed clutches of eggs had an average clutch size of 6.3 (range, 3-10 eggs). Of the 25 nests, 9, or 36 per cent, hatched successfully, 7 were destroyed by unknown causes, and 8 were deserted. The fate of 1 nest was not determined. Copulation. — Observations on copulatory behavior were recorded to deter- mine the seasonal occurrence and the sequence of displays normally involved in this activity. My observations agree with Gullion’s (1954:373) . Copulatory activity extended over about 1 month, but probably occupied a shorter period of the cycle of each pair. All records of copulation occurred between 13 May and 2 June. Some nests were initiated in early May so copulation must have occurred earlier for some. The period of copulation was closely associated with the egg-laying period. Once a female completed her clutch, copulation was rarely seen. Copulatory attempts, by males, were observed as late as 19 June. Similar findings were reported by Lelek (1958) for the European Coot. Laying. — The normal pattern of laying has been described by Sooter (1941) and Cullion (1954) who agreed that American Coots lay eggs at intervals of slightly more than 24 hours. Cullion reported a 48-hour gap between two eggs on two occasions, but two eggs were laid on the day following one of these long periods. Sooter (1941) reported that two eggs were laid in two nests in 1 day. These data would be influenced by the recording time and may not reflect the true interval between laying. Because coots are usually very aggressive, it seemed unlikely that females could avoid the intense territorial defense of most coots to lay eggs in a nest Leigli H. Fredrickson COOT BREEDING BIOLOGY 451 Data ON Clutch Table 2 Size of the American Coot Clutches Number Range Mean size Location Source and date 169 5-13 9.9 Manitoba Kiel (1955) 104 1-11 6.08 Iowa Sooter (1941) for 1936 347 4^18 7.92 Iowa Sooter (1941) for 1937 15 6-16 8.93 Iowa Present study 1963 87 6-17 9.85 Iowa Present study 1964 81 6-13 9.23 Iowa Present study 1%5 98 4-13 8.16 Iowa Present study 1966 281 4-17 9.03 Iowa Present study overall mean 8'* 7-10 9.0 California Gullion (1954) 5” 4-8 6.4 California Gullion (1954) Early season clutches. Late season clutches. in another territory. It is known, however, that birds of other species do occasionally lay eggs in coot nests. Ruddy Ducks occasionally lay eggs in coot nests (Weller, 1959 and present study). In South America the Black-headed Duck { Heteronetta atricapilla) lays eggs in the nests of several species of coots and other birds (Phillips, 1925; Weller, 1968). Promiscuous laying occurs in the European Coot ( Alley and Boyd, 1947) and this suggests that similar behavior might occur in the Nearctic form. Evidence from this study suggests that more than one female might lay eggs in the same nest. Two eggs were added to a nest on 3 consecutive days. Ihe pair associated with nest was marked, and no other coots were observed on or near the nest. Observations on the nest were not continuous, hut it seems unlikely that all eggs were deposited by a single female. Another nest contained 12 eggs; 4 of these eggs were slightly different in shape, were darker in color, and had a different pattern of black flecks than the other 8 eggs. A recent paper by Lahisky and Jackson (1966) indicated that caution must he used when associating egg color with a particular female because eggs of the Ring-necked Pheasant (Phasianus colchicus) were variable lor each hen studied. Because the development of the four eggs lagged a week behind other eggs in the clutch, parasitic laying probably occurred. In this study, I assumed clutches were the product of two or more females when clutches were in excess of 12 eggs, when eggs were of different sizes or shapes and when two eggs were laid on the same day. Clutch size.— I examined 565 coot nests. Eor 281 nests the mean clutch 452 THE WILSON BULLETIN DeccniBer 1970 Vol. 82, No. 4 Frequency of Occurrence OF Clutch Iowa in Table 3 Size in the 1963 through American 1966 Coot in Northwestern Number of nests Clutch size 1963 1964 1965 1966 Total % 4 0 0 0 3 3 1 5 0 0 0 2 2 1 6 1 3 3 9 16 6 7 4 7 5 22 38 14 8 1 7 15 24 47 17 9 5 17 22 17 61 22 10 2 25 27 14 68 24 11 1 17 3 2 23 11 12 0 6 4 2 12 4 13 0 2 2 3 7 2 14 0 1 0 0 1 — 15 0 1 0 0 1 — 16 1 0 0 0 1 — 17 0 1 0 0 1 — Total 15 87 81 98 281 — varied as follows (Table 2): 1963 — 8.93 (s.D. ±5.99), 1964 — 9.85 ( s.d. ±2.16), 1965 — 9.23 (s.d. ±1.67), 1966 — 8.16 (s.d. ±1.87), and overall mean 9.03 (s.d. ±2.01 ) . A null hypothesis of no differences between the means was tested with Duncan’s new multiple range test ( Steel and Torrie, 1960 ) . At the 5 per cent level, the clutch size of 9.85 in 1964 was significantly larger than the clutch size of 8.16 in 1966. The frequency distribution of clutch size in nests studied from 1963 through 1966 is summarized in Table 3. These data show that clutches with more than 12 eggs or less than 7 eggs were uncommon. Clutches of 10 eggs occurred most commonly, but clutches with 9 eggs were nearly as common. The data presently available on clutch size in the American Coot are inadequate to determine if variations exist in clutch size because of geographical location ( Table 2 ) . Clutch size of the American Coot does vary seasonally. Late clutches in California average 6.4 eggs (Gullion, 1954), or 2.6 fewer eggs per clutch than in early clutches. Much of Sooter’s data probably reflect the smaller clutches in late nests. Data collected on clutch size during the 4 years of my study were plotted against time (Lig. 3). Early clutches tended to he larger than late clutches. When the average clutch size was calculated on a weekly basis starting with the first of May, an average of 11.1 eggs per clutch for the Leigh H. Fredrickson COOT BREEDING BIOLOGY 453 N = NUMBER OF NESTS X = MEAN CLUTCH SIZE first week of May dropped to an average of 5.3 eggs per clutch for the seventh week of nesting. A null hypothesis of no differences between the means for the 7 weeks was tested with Duncan’s new multiple range test (Steel and Torrie, 1960). At the 5 per cent level, the following comparisons were significantly different: 11.1 from all means of 8.8 or less, 10.1 from all means of 7.8 or less, 8.8 from all means of 6.5 or less, and 7.8 from all means of 5.3 or less. Similar data have been reported for Blue-winged Teal (Bennett, 1938) and for other dabbling ducks by Sowls (1955). The smaller clutches appearing later in the season may be the result of renesting or of first nests of young birds. 454 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Incubation behavior. — Researchers studying the American Coot have not agreed on the time of initiation of incuhation in relation to the numher of eggs in the nest. Sooter (1941) reported that incuhation commenced with the first egg, hut he did not present supporting evidence. Gullion (1954 ) ob- served that incubation began with the first egg only on second clutches. In first clutches, initiation of incubation was variable: some birds started incubation after two eggs were laid, but others completed the clutch before incubating (Gullion, 1954:377). My observations indicated coots spent some time on the nest as soon as the first egg was laid, hut evidently incubation was insufficient during the first 3 or 4 days of laying to induce embryonic development. Eggs were generally cold in nests with less than four eggs, hut eggs were usually warm in nests with four or more eggs. A similar situa- tion has been recorded for Red-fronted and Red-gartered Coots {Fulica riififrons and F. armillata) in Argentina (Weller, 1968:194). Eggs usually hatched over a period of several days, but the appearance of three or four young during the first day of hatching is the result of this incubation behavior. Because laying and incubation occurred during the same period, some confusion has resulted in determining the length of incubation. Gullion (1954:383) studied this problem closely on four nests by marking eggs as they were laid. The eggs hatched in 23 days. My data are not directly com- parable with Gullion’s because I used the Heinroth method (interval between the last egg laid and the last egg hatched) to determine the incubation period. Only three nests were checked frequently enough to determine incuhation of 23, 24 and 27 days. Four other nests were known to have hatched between 21 and 25 days. Both members of the pair share in incubation. According to Gullion (1954:378), the male was most often on the nest during the night and for a few short intervals during the day. In 11 observations during my study a nest-changeover ceremony was never recorded, hut the possibility of vocal signals cannot he ruled out even though no evidence is presently available to support this possibility. In eight of the changes observed, one member of the pair had left the nest before the arrival of the mate. In all eight observations the identification of sex was positive. When the incubating bird entered the nest, it preened its breast and belly regions from one to 9 minutes before settling on the eggs. Brooding,. — Because all eggs in the clutch do not hatch simultaneously, coots must continue to incubate but also must feed and brood the young that have hatched. Newly-hatched coots are capable of movement (precocious) and are covered with down ( ptilopaedic) and are able to leave the nest as soon as they are dry ( nidifugous ) . Nice (1962) places the rails in her Precocial Category IV, which includes chicks that follow their parents and Leigh H. Fredrickson COOT BREEDING BIOLOGY 455 aie fed by them. Both parents shared in brooding the young, hut one of my observations on two marked pairs indicated that the male had a greater share of the brooding responsibility. After all the eggs had hatched young coots traveled with both parents during the day and did not appear to favor one sex. At dusk, when broods moved to platforms, the male seemed to assume the responsibility of caring for most of the young. Observations on two broods with marked adults indicated that in both cases the males brooded five and 10 young respectively and the females remained nearby without young. Young birds were particularly prone to wetting for a few days following- hatching. Leathers of the young birds were oiled directly by hilling move- ments of the adults from their preen glands to the young. Adults also oiled their young by rubbing their oiled underwing and breast feathers on the newly-hatched young. Wild young with parents appeared less prone to wetting than were captive birds that were reared without parental care. As soon as young coots were dry, they pecked at egg shells and larval insects dropped in the nest. When adults approached, the young birds begged vigorously. The wings were outstretched and moved rapidly in a vertical plane. The head was raised and rotated backward so that the occiput rested against the back or was held directly above it. The head usually moved from side to side. During the first days following hatching, the young coots appeared de- pendent on the parents for food. Both sexes collected food for the brood. When one member of the pair was feeding the young at the nest, the mate collected food and then presented it to the incubating bird which in turn fed the young. Larvae of aquatic insects and small crayfish were foods commonly fed to chicks. Nest sanitation. — Both sexes removed egg shells and vitelline membranes from the nests soon after the young hatched. The adults either ate the egg shells or carried them from the nest and dropped them into the water. Egg shells eaten at the nest accounted for many of the small chips usually associated with successful coot nests. SUMMARY Both sexes of the American Coot share in nest construction. Coots used a variety of nest materials but seemed to use materials readily available, particularly dry materials. The number of platforms constructed by coots during a breeding cycle may depend on the availability of other structures in the marshes such as lodges built by muskrats. Even though coots used other structures for brooding and copulation, coots always constructed their own nests. Cold spring weather appeared to delay Itreeding and reduce the average clutch size from 10 to 8. Coots also were influenced by habitat conditions. Birds nesting late in 456 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 suboptimal habitat tended to have smaller clutches. It was not known whether this was because of the habitat or merely reflected the physiological condition of birds as- sociated with a particular habitat. In either case, these clutches not only contained fewer eggs but had a lower nest success than birds nesting in good habitat. Soon after hatching, the parents either ate the egg shells or carried them from the nest and dropped them in water. Because eggs in coot nests hatched over a period of several days, both brooding and incubation behavior were conducted simultaneously. During the first week after hatching, young birds were fed large quantities of aquatic insects and were brooded by the parents. Males appeared to do most of the brooding at night. ACKNOWLEDGMENTS This study was supported by Project 1504 of the Iowa Agricultural Experiment Station, by Pittman Robertson Project W-105R and by an Iowa State Research Fellowship. I am indebted to Dr. Milton W. Weller for his encouragement and criticism throughout the study. Gerald Horak, Thomas Neal, and J. Douglas Thompson provided many hours of field assistance. Glenn Jones of the Iowa Conservation Commission provided quarters and assistance on the study area. Dr. W. Reid Goforth reviewed the manuscript. LITERATURE CITED Alley, R., and H. Boyd. 1947. The hatching and fledgling success of some coot. Brit. Birds, 40:199-203. Anderson, A. 1963. Patagial tag for waterfowl. J. Wildl. Mgmt., 27:284—288. Bennett, L. J. 1938. The Blue-winged Teal: its ecology and management. Collegiate Press, Ames, Iowa. Fredrickson. L. H. 1968. Measurements of coots related to sex and age. J. Wildl. Mgmt., 32:409-411. Fredrickson, L. H. 1969. An experimental study of clutch size of the American coot. Auk, 86:541-550. Glover, F. A. 1956. Nesting and production of the Blue-winged Teal (Anas discors Linnaeus) in northwest Iowa. J. Wildl. Mgmt., 20:28-46. Gullion, G. W. 1950. Voice difference between sexes in the American Coot. Condor, 52:272-273. Gullion, G. W. 1951. The frontal shield of the American Coot. Wilson Bull., 63: 157-166. Gullion, G. W. 1952f/. Sex and age determination in the American Coot. J. Wildl. Mgmt., 16:191-197. Gullion, G. W. 19526. The displays and calls of the American Coot. Wilson Bull., 64:83-97. Gullion, G. W. 1953f/. Observations on molting of tbe American Coot. Condor, 55: 102-103. Gullion, G. W. 19536. Territorial behavior of the American Coot. Condor, 55:169-186. Gullion, G. W. 1954. The reproductive cycle of American Coots in California. Auk, 71:366-412. Kiel, W. H. 1955. Nesting studies of the coot in southwestern Manitoba. J. Wildl. Mgmt., 19:189-198. Kornowski, G. 1957. Beitrage zur Ethologie die Blassbubns. J. OrnithoL, 98:318-355. Labisky, R. R., and G. L. Jackson. 1966. Characteristics of egg-laying and eggs of yearling Pheasants. Wilson Bull., 78:379-399. Leigh H. Fredrickson COOT BREEDING BIOLOGY 457 Lelek, a. 1958. Contributions to the hionamy of the coot (in Czech, English summary). Zool. Listy, 7:143-168. Low, J. B. 1945. Ecology and management of the Redhead Nyroca americana. Iowa Ecol. Monogr., 15:35-69. Nice, M. M. 1%2. Development of behavior in precocial birds. Trans. Linnaean Soc. New York, 8:1-211. Phillips, J. C. 1925. A natural history of ducks. Vol. 3. Houghton-Mifflin Co., Boston. SoOTER, C. 1941. Ecology and management of the American Coot Fulica americana americana Gmelin. Unpuhl. Ph.D. Thesis, Iowa State University, Ames. SowLS, L. K. 1955. Prairie ducks. Stackpole Co., Harrisburg, Pennsylvania. Steel, R. G. D., and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill Book Co., New York. SuGDEN, L. G., AND H. J. PosTON. 1968. A nasal marker for ducks. J. Wildl. Mgmt., 32:984-986. Walker, L. W. 1932. Spirit of the tules; the coot. Birdlore, 34:322-324. Weller, M. W. 1956. A simple field candler for waterfowl eggs. .1. Wildl. Mgmt., 20:111-113. Weller, AI. W. 1957. An automatic nest-trap for waterfowl. J. Wildl. AIgmt., 21: 456-458. Weller, AI. W. 1959. Parasitic egg laying in the Redhead (Aythya americana) and other North American Anatidae. Ecol. Monogr., 29:33-365. Weller, M. W. 1968. The breeding biology of the parasitic Black-headed Duck. Living Bird, 7:169-207. Westerskov, K. 1950. Alethods for determining the age of game bird eggs. J. Wildl. AIgmt., 20:274-279. Wetmore, a. 1920. Observations on the habits of birds at Lake Buford, New Alexico. Auk, 37:221-247, 393-412. DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, IOWA STATE UNIVERSITY, AMES, IOWA. (PRESENT ADDRESS: GAYLORD AIEMORIAL LABORATORY, UNIVERSITY OF MISSOURI, PUXICO, MISSOURI 63960.) 17 FEBRUARY 1969. NESTING SUCCESS AND MORTALITY OF NESTLINGS IN A CATTLE EGRET COLONY Julian L. Dusi and Rosemary T. Dusi The writers have reported the complete failure, in 1965, of two nesting at- tempts of Cattle Egrets { Bubulcus ibis ) in a colony located 15 miles southeast of Dothan, Houston County, Alabama ( Dusi and Dusi, 1968). At that time, the slight nesting facilitation effects of a small colony, prolonged drought, and predation, were the ecological factors considered to be respon- sible for the failures. During the 1967 season, a strong population and more ideal climatic condi- tions were present. The season seemed very similar to those of 1963 and 1964, when a strong population was present and a large number of young was pro- duced. The major difference was that in 1963—64, the Little Blue Heron {Flor- ida caerulea) was the dominant species and the Cattle Egret a lesser one. In 1967 the Cattle Egret was dominant (about 8,000 adults) and the Little Blue Heron represented by only about 300 adults. Other species were about the same: the White Ibis (Eudocimus albus) about 1,000; Common Egret iCasmerodius albus) 20; Snowy Egret [Leucophoyx thul-a) 10; and Anhinga {Anhinga anhinga) 4 adults. Because this season very much resembled the previous successful seasons, we felt that an actual measurement of nesting success would be desirable for use in comparison with other seasons. The nesting started with the Little Blue Herons, Common Egrets, and Snowy Egrets first establishing nests; then the Cattle Egrets came in large numbers to nest and roost, intermingling with the nesting Little Blue Herons and dis- turbing their nesting with their territorial disputes. This caused a certain amount of destruction of Little Blue Heron nests. Some of the nests were taken over by Cattle Egrets and their eggs deposited with those already laid by the Little Blue Herons. PROCEDURES Fifty nests were selected along an erratic transect line. We simply started at one point and took the nests as they came using no selection bias. Tags were placed on the tree trunks about three feet above the water level, where they could he easily seen. A mirror on a pole was used for observing nest contents above eye level. Therefore, the nests were disturbed no more than would be done by walking through the swamp near them. Four trips were made, over a period of 26 days, to evaluate the success of nesting. RESULTS AND DISCUSSION In the 50 nests there was a total of 126 eggs, 121 Cattle Egret eggs and five Little Blue Heron eggs, with a minimum of one egg in one nest and a maxi- 458 Dusi and Dusi CATTLE EGRET NESTING SUCCESS ]5'J mum of seven eggs (3 Cattle Egret and 4 Little Blue Heron) in one. Clutch size averaged 2.42 eggs per nest. This is not much more than half of the usual clutch and is perhaps a result of a drought period of some extent before the nesting began. In one of the nests where there were already four Little Blue Heron eggs, three Cattle Egret eggs were added making a clutch of seven; in another there was one Little Blue Heron egg and only two Cattle Egiet eggs were added to complete the clutch. Eifteen nests (30 per cent I were successful and 35 (70 per cent) failed. Of the 126 eggs in the 50 nests, 18 (14.8 per cent ) hatched and produced fledg- lings. The number of initial failures, 15 (30 per cent) seems quite high. Of these, 14 were nests that were completely gone on the first visit after tagging. Poor construction did not hold them in place or the supporting structure broke and dropped them into the water. At this initial stage of nest development much territorial bickering was still taking place and this additional activity is hard on poorly constructed nests. Whether the birds renested elsewhere in the col- ony is not known. Nests were established in the colony after this date. Of the other 21 failures, all hut six resulted with the disappearance of the nest. This suggests that poor nest site selection and nest construction are the main causes of nest failure. The other six failing nests were a result of either desertion, infertile eggs, or possibly predation. The nests either became empty, or nothing happened to the eggs during the study; so, they were either deserted or did not hatch. In the case of the mixed clutches, eggs became reduced in number to two Cattle Egret eggs in the nest with a total of seven and the nest with two Cattle Egret and one Little Blue Heron eggs was lost. It is of interest, regarding mixed clutches, that in an isolated tree an unnumbered nest contained one young Cattle Egret and one Little Blue Heron, successfully reared together. Therefore, some mixed clutches were apparently reared successfully . . . prob- ably by Cattle Egrets. One extremely interesting cause of mortality of one of the nestlings was cannibalism (Dusi, 1968), In one nest with two young, examination showed that the three-week-old nestling was trying to swallow its dead 11-day-old nest- mate. It had swallowed the head and neck up to the body. The body was too large to be swallowed, resulting in an impasse. We did not alter the situation. The following day, observations showed that the neck of the dead young had parted at the body and the cannibalistic nestmate had apparently finished swallowing the head and neck. We removed the rest of the dead carcass from the nest. It is not known whether the younger bird was eaten alive or whether it had died first. It is known that frequently the younger bird(s) of a clutch 460 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 disappear and this observation of cannibalism may provide an explanation to some of this mortality. CONCLUSIONS If we consider the nesting success of 30 per cent, insofar as actual nests are concerned (14.8 per cent for the successful transition from eggs to fledged young) and project the probable additional mortality before the young com- pletely leave the nesting colony and then add the 70 to 80 per cent mortality rate for the rest of the first year (Dusi, 1963; Lack, 1949) ; the questions, not only of, “How can the species survive?”, hut also, “How can the Cattle Egret be so rapidly increasing in numbers?”, are overwhelming apparent. The picture is depressing and improbable from the individual nesting suc- cess standpoint. If, however, we think of the entire colony dynamics . . . the whole population concept . . . then quite a different picture emerges. Early in the nesting season (20 May), we estimated at least 4,000 Cattle Egrets, with 2.000 nests, in the colony. On 10 June, an evening count indicated at least 5.000 adults were present. A one-hour evening count, 4 August, totalled 6,650 adults flying in, in addition to those already in the area. We estimated a grand total of 9,000. Out of this colony we feel that at least 2,000 new individuals have been reared to a size where they were flying from the colony and pos- sibly another thousand was still in the final stages of fledging. Therefore, as a whole, the colony added 2-3,000 new Cattle Egrets to the total population and even though inefficiency had been great, the mass nesting effects have been to greatly increase the numbers of Cattle Egrets. LITERATURE CITED Dusi, J. L. 1963. Mortality in the Little Blue Heron. Alabama Birdlife, 11:39-42. Dust, J. L. 1968. Competition between Cattle Egrets and Little Blue Herons. Alabama Birdlife, 16:4-7. Dusi, J. L. and R. T. Dusi. 1968. Ecological factors contributing to nesting failure in a heron colony. Wilson Bull., 80:458-466. Lack, D. 1949. The apparent survival-rate of ringed herons. Brit. Birds, 42:74-79. THE DEPARTMENT OF ZOOLOGY-ENTOMOLOGY, AUBURN UNIVERSITY, AUBURN, ALABAMA, 29 MARCH 1969. GENERAL NOTES Mallard— Green-winged Teal associations in southern Wisconsin. — Mallards (Anas platyrhynchos) are involved in hyliridization more often than any other species of water- fowl (Kortright, The ducks, geese and swans of North America, 1967:43). Cockrum I Wilson Bull., 64:142, 1952) records, for North America, only the single wild Mallard X Green-winged Teal [Anas carolinensis) hybrid described by Stone (Auk, 20:209, 1903). Captive hybrids of these species are relatively common (Gray, Bird hybrids, 1958:23; Johnsgard, Condor, 62:28, 1960). This paper records our observations of two instances of unusual association between a male Green-winged Teal and a pair of Alallards in southern Wisconsin during the summer of 1969. One trio was first seen on Lake Mendota, Madison, Wisconsin, on 11 April by Nellis. He saw them nearly every day until 19 June when observations were terminated. During these observations, the male Green-winged Teal was always found closely associated with a hen and drake Mallard. The teal was nearly always seen between the male and female Alallards (Fig. 1) and was dominant over the larger drake Mallard. Pre- copulatory behavior was observed several times, but neither drake was ever seen to copulate with the hen. When the drake Mallard attempted to copulate, the teal chased him away, and when the teal attempted to copulate the hen became unreceptive. No aggression was shown by the male Alallard toward the teal. The constant association of tliese three birds for 70 days clearly suggested that the hen had no nest in this period. A second Mallard-Green-winged Teal association was observed twice weekly from 2 June until 23 July by Zohrer on a farm pond 40 miles west of Madison. A drake Green- winged Teal was associated with a pair of marked, wing-clipped “wild” Mallards. The Fig. 1. The usual spatial relationship of the three members of this “trio” with the teal between the Mallards, Lake Mendota, Wisconsin, 13 June 1969. 461 462 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 teal was never seen in association with an additional hen Mallard or a Blue-winged Teal {Anas discors) present on this pond. Both in the water and on land the teal was always closer to this particular female Mallard than to any other duck. Aggression was not seen between the three members of this trio. Several similarities are apparent between these two associations. In both cases, the female Mallard was “paired” with a drake Mallard and a drake Green-winged Teal. Neither hen was observed to copulate with either male. To our knowledge, neither hen prodneed a brood, and neither was incubating when observations ceased. The potential for hyl)ridization was not realized in either case. Both associations occurred in southern Wisconsin, which is outside the normal breeding range of Green-winged Teal. We wish to thank P. A. Johnsgard for advice in preparing this manuscript. — Carl H. Nellis, James J. Zohrer, and Daniel W. Anderson, Department of JVildlife Ecology, University of W isconsin, Madison, 28 October 1969. A second Swallow-tailed Kite record for Trans-Pecos Texas. — On 5 August 1969 an adult Swallow-tailed Kite i Elanoides forficatus) was observed soaring over Rio Grande Village, Big Bend National Park, Brewster County, Texas. It remained within a three-mile long area over the Rio Grande or its floodplain, on both sides of the river, including the vicinity of Boquillas, Coahuila, Mexico, from 09:30, when it was first fonnd and photographed by the author, until at least 16:30 when David Easterla observed it there. It remained in flight at all times, gracefully soaring with seven Turkey Vultures {Cathartes aura) and two Black Vultures [Coragyps atratus) . The record constitutes only the second sighting of the Swallow-tailed Kite for Trans- Pecos Texas. Johnson (Wilson Bull. 80:102-103, 1968) reported a lone bird over Fort Davis, Jeff Davis County (about 120 miles north of Rio Grande Village) on 26 August 1966. However, Pansy Espy (pers. comm.) ohsened a Swallow-tailed Kite over Fort Davis for 10 days; 25 August to 3 September 1966. These records are undoubtedly of post-nesting wanderers. The species is known to wander widely after nesting; Bent (U.S. Natl. Mus. Bulk, 167:52, 1938) reported many fall sightings from New Jersey to North Dakota west to Colorado and Carlsbad, New Mexico. In recent years there have been few fall sightings anywhere hut on its regular migration route. In Texas, one was seen north of Fort Worth in Denton County, 22 August 1966 (Williams, Audubon Field Notes, 21:52, 1967) ; and one was seen near Stockdale, Wilson County, 21 August 1964 (Webster, Audubon Field Notes, 19:57, 1965). Although the species once bred in eastern and central Texas, Wolfe (Checklist of the birds of Texas, 1956:18) considers it to he a “Very rare summer resident in southern area,” Galveston to Calhoun Counties, “and rare migrant south to Brownsville.” According to Allan Phillips (pers. comm.), the fact that the bird was seen also over Boquillas, Coahuila, Mexico, constitutes the westernmost Mexican record and only the second for Coahuila. Friedmann, Griscom, and Moore (Distributional checklist of the birds of Mexico. Part I, Pacific Coast Avifauna, No. 29:48) do not include a record for Coahuila. — Roland H. Wauer, Rig Bend Natl. Park, Texas 798.14, 24 September 1969. Giant water hug in an owl pellet, — Great Horned Owls {Bubo virginianus) and other owls feed on a variety of animals including even scorpions and centipedes (Bent, U.S. Natl. Mus. Bulk, 170:1938). The ability to consume species that possess stinging or biting body parts associated with toxic snhstances seems remarkable. On 12 October 1969 an owl pellet, probably that of Bubo virginianus, was found below a TV tower near Bithlo, Orange County, Florida. The pellet consisted largely of hair from an opossum (Didelphis December 1970 Vol. 82, No. -1 GENERAL NOTES 463 juarsupialis) and a giant water Jiug {Lethocercus sp.) ( Heniiptera: Belostomatidae) . The insect was intact and about 5 cm in length. Giant water bugs can inflict a notably venomous bite. — Walter Kingsley Taylor, Department of Biological Sciences, Florida Technological University, Orlando, Florida 32816, 20 November 1969. Egg transport recorded for the Red-bellied Woodpecker. — The activities of a pair of Reddiellied Woodpeckers {Centiirus carolinus) at a nest hole seven feet above the ground in a tree and 20 feet from my apartment door in Tampa, Florida, held my attention every morning, in the spring of 1968. On 25 June 1968, at 08:00, 1 suspected that perhaps one of the parents was feeding young since the tail of one of the wood- peckers bobbed in and out of the nest hole. A moment later it flew directly towards and only a few feet above me and disappeared behind some nearby buildings. As soon as it left the nest I noticed an unbroken, white egg in its bill, presumably its own, oriented with the larger end towards the tip of the bill. Unfortunately, I was unable to determine the sex of this bird. Egg transport, due to destruction of the nesting tree, has been recorded on film for the Pileated Woodpecker in Florida and noted for the Yellow-shafted Flicker in Massa- chusetts due to disturbances by Starlings (Truslow, Living Bird, 6:227-236, 1967). A record of the Red-bellied Woodpecker transporting House Sparrow eggs is given by Brackbill (Bird-Banding 40, 323-4, 1969). A high population of Starlings, one pair of which eventually occupied the evacuated nesting hole, may have been responsible for this unusual behavior in this present sighting. — Graham C. Hickman, Dept, of Biology, Texas Tech University, Lubbock, Texas 79415, 26 January 1970. Eastern Phoebe nesting in old Barn Swallow nest. — The Eastern Phoehe {Sayornis phoebe) often chooses unusual nesting sites and occasionally uses a nest, with repairs, in successive years (Bent, U.S. Natl. Mus. Bull., 179:141-142, 1942). I have found only one recorded instance, however, of a Phoebe laying in an abandoned nest of another species. Stoner (New York State Mus. Circular, 22:1-42, 1939) reported a case where a phoebe lined an old Barn Swallow iHirundo rustica) nest with horsehair and successfully fledged a brood from it. On 8 June 1%9, I inspected for possible reuse old Barn Swallow nests in a culvert near the Purdue Golf Course in West Lafayette, Indiana. A phoebe was flushed from a previous year’s Barn Swallow nest which had been unused this year. A check of the nest showed that it contained four fresh phoebe eggs. The nest was attached to a vertical concrete wall about five feet above a small stream which flowed through the culvert. It was made completely of mud and straw and apparently had not been modified by the phoebe. The eggs were resting on a few coarse straws which covered the mud base. .Subsequent checks revealed that these eggs were the complete clutch. On 26 June, all of the eggs had hatched and the adult phoebes were feeding the young. On that day, Russell E. Mumford, Purdue University, verified that the nest’s construction was that of the Barn Swallow. On 11 July, I flushed two fully fledged phoebes, able to fly well, from the nest, and they landed near an adult in a bush just outside of the culvert. Earlier in the year, on 4 May, a typical phoehe nest was found under the same culvert with a full clutch of four eggs. It, too, was attached to the vertical wall and was composed primarily of mud and moss. Bent fop. cit.: 142) said that moss is a constant component of phoebe’s nests.” The eggs had disappeared on 15 May and I removed the nest. It is possible, although not determined, that it was the same female that built this eailiei nest and later used the old Barn Swallow nest. If this was the case, it may lie that, being 464 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 ready to lay, she returned to reuse her old nest and, finding it gone, occupied the nearby (10 feet) Barn Swallow nest. — Harmon P. Weeks, Jr., Department of Forestry and Conservation, Purdue University, Lafayette, Indiana 47907, 17 November 1969. Hermit Warbler in Missouri. — On the afternoon of 20 December 1969 I observed a Hermit Warbler [Dendroica occidentalis) at an eight-acre conifer grove, 10 miles west of Maryville, Nodaway County, Missouri. The warbler was feeding in Scotch pines iPinus sylvestris) and Austrian pines iPinus nigra) with Pine Siskins i Spinas piniis) and Golden-crowned Kinglets ^Regains satrapa) . The warbler was collected and preserved as a study skin (DAE 2290). It was a first year male (skull slightly ossified; testes less than 1 mm; 10.5 gms; moderately fat) that appeared to be in good health. The Hermit Warbler has not been previously reported from Missouri (Easterla and Anderson, Checklist of Missouri birds. Audubon Soc. of Mo., 1%7) and is accidental in the eastern and midwestern United States with only two records (Cambridge, Minne- sota [A.O.U. Check-list, 1957:496] and Cambridge, Massachusetts [Audubon Field Notes, 18:425, 1964]) being reported. Besides several records from coastal California, this is the only other United States winter record for D. occidentalis (Ibid.). The factors which in- fluenced this bird to stray to Missouri are unknown. That it was healthy and was surviving a Missouri winter seems remarkable since this species normally winters in central southern Mexico (Ibid.). At the time of observation the temperature was 20°F and had been below freezing on previous days. Examination of tbe proventriculus and gizzard indicated an insectivorous diet which was surprising considering the time of the year. Food items were: stink bugs ( Pentatomidae) , pigmy locusts (Acrydiinae) , ground beetle (Carabidae) , leaf beetle (Chrysomelidae) , checkered beetle (Cleridae) , leafhopper ( Cicadellidae) , and spider ( Arachnida-Araneidae) . Appreciation is extended to Leroy Korschgen and Wilbur Enns, Columbia, Missouri, for identification of food items and to Richard C. Banks, National Museum, for con- firming identification of the warbler. — David A. Easterla, Department of Biology, Northwest Missouri State College, Maryville, Missouri 64468, 2 February 1970. Yellowthroat caught in common burdock. — On 26 September 1966 on tbe campus of Garden State Academy near Tranquility, Sussex Co., New Jersey, I found an adult male Yellowthroat (Geothlypis triclias) caught on the top of the common burdock {Arctium minus). Both feet had become entangled in the burs and the bird had fallen helplessly upside down; the legs were crossed and the tips of the primaries of the right wing were entangled in a lower bur. Tbe three-foot plant was in bloom at the time and the burs were noticeably sticky. While the Yellowthroat was being released, it made no attempt to bite. Judging from tbe appearance and activity of the bird, it seemed to have been trapped for only a short time. Since it took some effort to release the bird, it seemed clear that it was hopelessly entangled. Had the bird sundved the night, it would likely have died during the following day from predation, starvation, dehydration, or exposure. In my brief search of the literature I have found reports of a Calliope Hummingbird (Stellula calliope) entangled in grass (Setaria verticillata) barbs (Tucker, Condor, 57: 119, 1955), a Pearly-eyed Thrasher (Margarops fuscalus) trapped by sedge (Scleria Ulhosperma) (Bond, Condor, 62:294^295, 1960), two Herring Gulls (Larus argentatus) entangled in hound’s-tongue weed (Cynoglossum officionale) (Nickell, Auk, 81:555-556, 1964), a Common Tern (Sterna hirundo) caught in a prickly lettuce iLactuca scariola) plant (Houston, Blue Jay, 24: 79, 1966), an American Widgeon (Mareca americana) December 1970 Vol. 82, No. 4 GENERAL NOTES 465 stuck in willow (Salix sp. ) branches (Sherick, Blue Jay, 24: 143, 1966), and a Red- shouldered Hawk (Buteo lineatus) trapped hy Spanish moss (Tillaridsia sp.) (Funder- Imrg, Florida Naturalist, 40:65, 1967). In Saskatchewan, young Turkeys ( Meleagris gallopavo) are reported to frequently get caught in the sticky sap of gumweed iGrindelia perennis) (R. W. Nero, pers. comm.). Arthur P. Cooley of East Pachoque, New York, reported a Pine Siskin [Spiniis pinus) trapped in common burdock {Arctium minus) ( O. L. Austin, Jr., pers. comm.). The Cornell Laboratory of Ornithology reported a dead Black-capped Chickadee iParus atricapillus) gripped by the burs of a burdock i Arctium sp.) in an attempt to extract seeds (Archibald, Newsletter to Members, 55:4, 1970) . From all indications, the frequency of entanglements in vegetation appears to he fairly common especially in the Arctium species. — Richard D. Brown, Science Dept., P.O. Box 10, Garden State Academy, Tranquility, New Jersey 07879, (Present Address: Dept, of Zoology, Ohio State Univ., Columbus, Ohio 43210) 30 December 1969. The double-scratch in the genus Pooecetes. — During the summer of 1969, I ob- served Vesper Sparrows (Pooecetes gramineus) double-scratching as they fed in a garden plot near Frederick, Frederick County, Maryland. This behavior was observed infrequently and consisted primarily of a rapid backward kick of both feet. Harrison ( Wilson Bull., 79:22-27, 1967) had no evidence of this behavior in this genus — Walter Kingsley Taylor, Department of Biological Sciences, Florida Technological University, Orlando, Florida 32816, 20 November 1969. Common Crackle kills Cedar Waxwing in air. — During the first week of August, 1966, I saw a Common Crackle (Quiscalus quiscula) kill a flying, immature Cedar Waxwing ( Bombycilla cedrorum) . At Lac des Abatis, 40 miles east of Gracefield, Quebec, Canada, I was observing a flock of Cedar Waxwings feeding some 60 feet above a sandy point that jutted into the lake. Evidently an eddy in the air by a lone white pine was providing insects. A Common Crackle flew into the flock from above, hit one bird a blow, apparently on the nape, and followed its fall to the ground. The bird was dead, its neck broken by the time I reached it from 50 yards away. The grackle flew off at my approach. I examined the waxwing and took it to our fishing camp to skin. Looking back, I saw the grackle return, and search for its kill at the spot of the fall. It walked about the area, hunting thoroughly between the short marsh grasses, and then left. The skull of the waxwing showed no ossification. According to James Baird (pers. comm.) there are a number of references in the literature to Common Crackles killing or attacking birds the size of House Sparrows. Baird and Smith (Wilson Bulk, 77:195, 1965) comment on “the improbability of a grackle succe.ssfully pursuing and capturing a healthy small bird.” Here, however, is an instance. I am grateful to Mr. Baird for his interest, and assistance, in this note. — Erma J. Fisk, 17101 S W 284 Street, Homestead, Florida, 31 October 1969. First nesting colonies of the Lark Bunting in Missouri. — The Lark Bunting iCalamospiza melanocorys) is a Great Plains species that has not been recorded breeding eastward into Missouri. Easterla and Anderson (Checklist of Missouri birds. Audubon Soc. Mo., 1967) consider the species as an accidental transient and summer visitant in the northwestern corner of the state. Two specimens and seven sight records are recorded for Missouri, with all of the sight records of recent occurrence. On the morning of 5 June 1969 while conducting a Breeding Bird Survey in north- 466 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 western Missouri, I discovered a colony of breeding Lark Buntings in a field two miles northwest of Tarkio, Atchison County. A minimum of nine males and three females were observed. The males were often observed in aerial song displays when not perched on a weed stalk or fence. That afternoon, I flushed a female from a partially completed nest. The nest (photographed) was in a dug-out depression in a clump of young (10-12 inch tall) cocklebur {Xanthium sp.). It was constructed of last year’s dead soybean stalks that were scattered throughout the field. For one hour I observed and followed another pair of Lark Buntings that flew to an adjacent, fi'eshly plowed corn field to feed. During this time the male was observed to court and copulate with the female from eight to ten times. The gonads of a male and female which were collected (DAE 2263, 2264) indicated breeding ( testes-15 X 10 mm; ova-5 X 5 mm and below). They weighed 37.5 and 36.5 g. The colony was in an 80-acre field that had been cultivated and sown (drilled?) to orchard grass (Dactylis glomerata) in spaced 12-inch rows earlier in the spring. At the time of discovery the orchard grass was short (8-12 inch tall) with numerous young (10-12 inch tall) cocklebur plants growing between the rows. Plant cover was about equally distributed between cocklebur and orchard grass. The 80-acre field and sur- rounding farmland has a rolling terrain and at the time the farmland was either freshly plowed corn fields or tall (3 ft) orchard grass. On 2 June 1969 J. Fairhe observed a courting pair of Lark Buntings in a field near Lake Contrary, south of St. Joseph, Buchanan County. By 4 June a colony of at least 10 males and two females were established. Male Lark Buntings were often observed in tbeir aerial song displays and copulation between pairs was observed twice. On 4 June Fairlie found a female Lark Bunting impaled on a barb wire fence. Loggerbead Shrikes [Lanius ludovicianus) were possibly responsible. On 9 and 11 June Fairlie and F. Lawhon observed a female carrying nesting material. Lawhon and Fairlie continued observing this breeding colony up until 1 July when at least two pair (male and female photographed) were still present with both of the females observed carrying food, presum- ably to young. These two colonies are 59 air miles apart. The invasion of breeding Lark Buntings into northwestern Missouri appears to be a recent phenomenon regulated by changes in climate and land use that have influenced other western and southwestern fauna to recently expand their range into Missouri (Brown, Condor, 65:242-243, 1963; Schwartz and Schwartz, The wild mammals of Missouri. Univ. Mo. Press, Columbia, pp. 334-335, 1959; Warner, Wilson Bull., 78:289-300, 1966). At the Atchison County breeding colony there was a considerable amount of bare ground between the orchard grass and cocklebur which could have originally attracted the Lark Buntings to the field, perhaps simulating the short grass prairie conditions preferred by the species to the west. Human disturbances such as plowing, cultivating, and the planting of crops undoubtedly make the habitat more favorable for breeding Lark Buntings and could aid the species in extending its breeding range eastward into Missouri. These two northwestern Missouri nesting colonies are the first breeding records for Missouri and represent one of the easternmost breeding localities for the species. Appar- ently the nearest breeding site to Missouri is that recorded by Rice (Bull. Kansas Ornithol. Soc., 16:1-2, 1965) wbo observed a nesting colony during June-July 1%4 in northeastern Kansas (Shawnee County) a distance of 90 and 70 air miles southwestward from the Atchison and Buchanan County sites. Appreciation is extended to Floyd Lawhon and James Fairlie for making available their field notes. — David A. Easterla, Uepartnient oj Biology, Northwest Missouri State College, Maryville, Missouri 64468 12 January 1970. ORNITHOLOGICAL NEWS The Fouith Annual Arthur A. Allen Award fur distinguished service to ornithology was presented to Alexander Wetniore on 17 Octoher 1970 by the Cornell University Laboratory of Ornithology. Harrv C. ^lonk, Johnson A. Neff, George M. Sutton, and Gordon Wilson were added this year to the list of 50-year members of the Society. We have learned of the recent death in an automobile accident of James Fisher, one of the English-speaking world’s most well-known ornithologists. FROM THE AOU At its annual meeting in Buffalo, New York on 5 October 1970 the AOU elected the following officers: Robert W. Storer, President Richard C. Banks, Secretary S. Charles Kendeigh, First Vice-President Burt L. Monroe, Jr., Treasurer Joseph J. Hickey, Second Vice-President Oliver L. Austin, Jr., Editor The colorplate in this issue has been subsidized by the generosity of one of our members. The Eastern Bird Banding Association announces that it will again make an award of 1250 to a student, undergraduate or graduate, who uses bird banding in an ornitho- logical study. The deadline for applications for the award must be received prior to 25 Fel^ruary 1971. Further information can be obtained from, and applications should lie suljinitted to: Mrs. Roger W. Foy, Secretary, Eastern Bird Banding Association, Box 164, Ship Bottom, New Jersey 08008. The Faculty of Zoology and the Office of International Programs of The Ohio State University announce plans for a study tour to Kenya and Tanzania entitled, “Ecological and Biogeographic Problems in East Africa” to he held in the Spring Quarter of 1971. Up to 15 quarter hours of credit can he earned. Further details can lie obtained from Dr. Abbot S. Gaunt, Academic Faculty of Zoology, The Ohio State University. Columbus, Ohio 43210. The United States National Museum has recently l)een divided into two separate Museums, the National Museum of Natural History and the National Museum of History and Technology, both bureaus of t)ie .Smithsonian Institution. The U. S. National Museum now consists only of the Office of the Registrar, Administrative and Exhibit Offices. Because all national biological and paleontological specimens (including those of the d67 468 THE WILSON BULLETIN Decemljer 1970 Vol. 82, No. i former Biological and Geological Surveys, and Fish and Wildlife Service) have been and still are accessioned througli the Office of the Registrar, it is appropriate to continue the designation, USNM, for specimens in all Smithsonian Museums. During the second half of 1971 the bird collections of the British Museum (Natural History) will he moved from London to the Zoological Museum, Tring, Hertfordshire. The earliest stages of the move will begin about April, and from then until the move is completed it will not be possible for the museum to provide all the usual facilities for visitors or to send out loans from all parts of the collection. For a period of several weeks in the second half of the year it will be necessary to close the collection to visitors. The collection will be redioused in what was the Rothschild Museum at Tring, to which a substantial new wing is being added. Louis Agassiz Fuertes Research Grants These grants, established in 1947, are devoted to the encouragement and stimulation of young ornithologists. One particular desire is the development of research interests among amateur ornithologists. Any kind of ornithological research may be aided. Re- cipients of grants need not be associated with academic organizations. Each proposal is considered primarily on the basis of possible contributions to ornithological knowledge. An anonymous donor gave $500 to found the fund; later donors have provided ad- ditional money. The Council of the Wilson Ornithological Society has added funds as necessary to provide at least one $100 grant annually. Two grants have been made in several recent years; last year the grants were for $200 and $100. Although grantees are not required to publish their studies in The JTilson Bulletin. it is hoped that they will submit their manuscripts to the Editor of the Bulletin for consideration. Since its inception, the Fuertes Research Grant has been awarded to 29 persons, many of whom have continued their research work. Application forms may be obtained from Val Nolan, Jr., Department of Zoology, Indiana University, Bloomington, Indiana 47401. Completed applications must he re- ceived by 1 March 1971. A new award of $100 annually, to he known as the Margaret Morse Nice Award, has been made possible by the generosity of an anonymous donor of $500 to the Wilson Ornithological Society. Candidates for this award are limited to persons not affiliated with a college or university. Interested persons should write to Val Nolan, address given above. ORNITHOLOGICAL LITERATURE UiKus or North America. By Lotus and Margery Milne. Prentice-Hall, Englewood Cliffs, New Jersey, 1969 : 9 X 12 in., 13 + 340 pp., 300 paintings by Marie Nonniast Bohlen. $25.00. We have here a bookseller’s dream — something big, splashy, and expensive — to capitalize on the ever burgeoning market for books about birds. The publisher tells us on the jacket’s front flap that this is “a distinguished portfolio ... of 300 full-color paintings of birds — breathtaking renditions which have heen widely acclaimed by art critics. . . . [The] portraits give details of plumage and markings which are not captured liy even the most accurate cameras.” Finally, after extensively praising the literary style of the text, the publisher proclaims: “To established bird lovers, this book is indis- pensable; to novices, it is an irresistible introduction to some of the most beautiful creatures of one continent. . . . North American Birds is a valued addition to every home, school, and library.” In no respect can this book be any such addition. As a portfolio of bird art it is nothing less than a travesty. Each species, usually represented by an adult male only, is depicted in exaggerated and often unlife-like colors. Worse still, the publisher has chosen to blow up the paintings to startling size, thereby detailing and accentuating their dismal failure as accurate delineations. Thrushes, mimids, indeed all passerines, as well as plovers and other non-passerines, have the same scutellated tarsi. In flight, some species have anywhere from five primaries (e.g., the Western Bluebird, p. 20) to a dozen (the Pintail, p. 241, has 15 primaries in one wing and 11 in the other). The spread toes of the Semipalmated Plover (p. 306) fail to indicate the reason for the species’ name, and the foot of the Belted Kingfisher (p. 291) gives no suggestion of syndactylism. The bill of the American Redstart (p. 119) is typically parulid rather than flycatcher-like as it should be. And so on. While these inaccuracies might be forgiven as artistic license, the inept and frequently ludicrous form of bird after bird cannot. Tlie worst depictions are those of liirds in flight. Wings, in some cases no more flyable than an angel’s, appear boneless, out of proportion to body, and improperly positioned. Many birds (e.g., tbe Ruby-crowned Kinglet, p. Ill) look stiff, as if in rigor mortis, their feet and toes grotesquely angled and extended. There are gross errors. The painting of the Gray Jay (p. 193) is labelled Clarks Nutcracker; the painting of the Clark’s Nutcracker ( p. 101) is labelled Gray Jay. And there are misspelled scientific names (pp. 93 and 299) . What there is of text is lirief and, while factually acceptable, contributes little or nothing that cannot already be found in current field guides. Information about each siiecies, usually given on the page with the jiainting, or on the one opposite, is mainly an elucidation of what the painting shows with additional mention of sexual differences (or similarities) and, if space allows, food habits, habitat preferences, etc. (There is no explanation as to why the male Summer Tanager, p. 127, is shown on the nest.) Occasionally the total information on one species is contained in a single sentence. So much for my comments on the liook. Disturbing as are its many sbortcomings, even more disturbing has been its ready and uncritical promotion hy parties who should be discriminating in their choice of bird books. A national wildlife oiganization and one of the largest state Audubon societies, whose officers are surely qualified to judge tbe value of a bird book, circularized their members with an eye-catching flier extolling this work as indispensable and suggesting its purchase directly from theii home offices. Were the officers so gullible as to accept the publishers claims without fiist peiusing 469 470 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 the work, or were they so zealous for income as to take on a patently sellable item without regard for its value? Only slightly less distuiTing have been reviews or notices of this hook in some local ornithological and conservation journals that have simply repeated the publisher’s claims without any qualification whatsoever. Procedures of this sort reflect deplorable irresponsibility on the part of organizations and journals. To their members and subscribers they are doing a great dissenuce. — Olin SeW'All Pettingill, Jn. Wildlife Management Techniques. By Robert H. Giles, Jr., editor. The Wildlife Society, 1969: X 8% in., 623 pp. $10.00. The increasing sophistication of technology has provided biologists with an imposing array of electronic and mechanical gadgetry with which to make refined measurements and gather kinds of data previously unobtainable. Most of this technology has been developed for laboratory use; but the techniques utilized by field biologists have also been broadened and refined, although the field biologist more often can implement his re- search with simpler equipment than can the laboratory technician. “Wildlife Management Techniques” has undergone a gradual evolution that began in 1938 and has passed through seven editions with several different titles and editors. The present volume is an attractive publication filled with valuable information on a wide variety of topics pertaining to techniques utilized in wildlife biology. Twenty-five contributing authors wrote 24 chapters and compiled seven appendices in this 623-page volume. Fifty pages cite approximately 1,800 references, and a thorough index contains some 11,000 items. The book is well illustrated witli 202 figures plus numerous tables. The editor describes this edition as “ ... a textbook and manual for well-educated people working with game mammals and birds.” The major aim of the hook “ ... is to improve the management of the wildlife resource through more rapid development and improved use of techniques.” “ . . . the objectives are to describe the major approaches to problem solving, suggest ways of implementing these solutions, describe and direct readers to some of the better techniques and tools now known, and indicate gaps in our knowledge.” The following rundown, although succinct, on the kind of information brought together in this publication will clearly indicate its relevance to a variety of ornithological field problems, whether tliey involve gallinaceous birds or passerines. SevCx'al chapters include such practical infonnation as brand names of supplies and equipment, their costs, and addresses from which the information or materials or both can he obtained. The scope of the book is broad, including chapters that discuss bibliographic tools and reference sources, methods of setting up reference files and a reprint collection, and procedures for preparing a manuscript for publication. One chapter reviews various types of instrumentations that have been used to gather data in a wide variety of mammal and bird studies — many of them with non-game animals. The hook includes a short, hut well written, chapter on computers. Different kinds are briefly described and compared. The author discusses how to evaluate whether or not one should use a computer and concisely describes its use. The chapter also provides several examples of computer use in wildlife management. A chapter on radio-location telemetry includes information on the variety of transmitters, methods of attachment to the study animal, receiving systems, and the degree of accuracy in locating the transmitting organism. This chapter might have lieen expanded to describe the process of telemetry in greater detail and to review more thoroughly some findings resulting from the use of this technique. December 1970 \ ol. 82, No. 1 ORNITHOLOGICAL LITERATURE 171 The book’s longest chapter concerns the sexing and aging of game birds and mammals. The section dealing with birds describes aging and sexing using plumage, gonads, the bursa of Fabricius, copulatory protuberances, penis, color of soft parts, spurs, size and shape of droppings, weights, measurements of various structures, and stage of molt. Parts of the chapter on habitat analysis and evaluation provide helpful information including methods of assessing the amount or density of covering vegetation, how to deter- mine the type and condition of the soil, how to measure the productivity of various seed crops, and the analysis of vegetation by sampling quadrats and plots and taking transects. Another chapter considers methods of collecting and preserving biological materials, in- cluding study skins, tissue samples, whole specimens, blood samples, and plant materials. Quite incongruous and unnecessary, I tliink, is a section on preserving game trophies and meat. More and more field studies require the marking of individuals to determine their role in the social system to which they belong. Thus, ornidrologists will find useful the section on trapping live birds, where the authors describe the use of several baited walk-in traps, netting, nest traps, and drugs for capturing birds, plus various ways of marking birds that include imping, banding, and dying. Two chapters dealing with animal populations clearly show the necessary orientation of population studies toward statistical analyses. These chapters include an explanation of the statistics of estimating populations, the various methods of sampling, and methods of taking direct animal counts in the field. Survival, recruitment, sex-ratio, age structure, population size and trends, methods of estimating these parameters, and ways of collecting data for studying populations are discussed. The chapters lack uniformity in the depth of their treatment. Some are sketchy, while others appear to deal rather thoroughly with tlie subject matter. The editor acknowledges this in the preface. This edition is almost entirely a newly written publication. Two of the chapters were completed three years prior to publication, however; and another was reproduced directly from the 196S edition. For years field biologists working with non-game animals have turned to the pages of The Journal of Wildlife Management or to one of the editions of this publication to learn techniques that might be applicable to their own studies; for wildlife biologists have pioneered in developing technicjues for gathering field data in many areas of study. Therefore, the usefulness of this volume stretches beyond the limits of those working with game mammals and birds. Ornithologists will find a great deal of useful information here, even though the chapters deal more with mammals than birds, and a few of the chapters have no applicability for one working outside the area of wildlife management. — D. A. Lancaster. Birds of the Early Explorers in the Northern Pacific. By Theed Pearse. Published by the author, 1968: 6 X 9 in., 275 pp., 4 hi. and wh. illustrations. $7.50 (available from Gray’s Publishing Company, Ltd., Sidney, British Columbia). The author has searched the journals of the travelers who penetrated the North Pa- cific north of a line between Vancouver Island and Kamchatka before 1830 for references to birds. Tlie excerpts he has extracted, which form the bulk of the text, range in sig- nificance from nugatory statements of “an abundance of sea fowls’' to historically quite important ones, e.g., descriptions of type specimens and species like the Spectacled Cor- morant { Phalacrocorax perspicillatus) , now extinct. Accompanying the excerpts are the 472 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 author’s attempts at identifying the birds described in terms of recent nomenclature. Many of the descriptions are tantalizing. The sort of person who, upon receiving a phone call from a neighbor describing an unusual bird at the neighbor’s backyard feeder, delights in trying to puzzle out which species it might be from the neighbor’s unpracticed de- scriptions will likewise enjoy matching wits with the author on similarily inadequately described birds. The accounts are arranged primarily by the country of origin of each expedition and then roughly chronologically. Why James Colnett is listed among the Spanish explorers is not explained. There are four pages of black-and-white photographs, four to a page, of some of the paintings that the artists on Cook’s last voyage, William Ellis and John Webber, made of birds of the North Pacific. The text is marred by frequent misspellings, clumsy sentences, repeated passages, and incorrectly numbered footnotes, all of which could have been put right by a professional editor. The author has gathered together many accounts from references that are rare or not generally available. For this, and for wading through many volumes to extract what little significant information there was on birds, the author will be thanked by researchers on North Pacific history. However, the book’s limited scope and careless editing detract from its general usefulness and appeal. — Warren B. King. The Hill of Summer. By J. A. Baker. Harper and Row, Publishers, 1970: 8V2 X 6 in., 159 pp. $5.00 There are admittedly as many ways of writing about nature as there are eyes to see and ears to hear. Some skim the surface and from the thin top layer create fine word pictures often lacking in life and substance. “The Hill of Summer” is poetry, in which one word picture flows smoothly into the next. “The sparrows’ chirping voices are bright nails in the dry grain of the air.” The metaphors might seem exaggerated and almost in- comprehensible. But slowly the reader becomes accustomed to the style of writing. And then he discovers how the use of words is made into remarkably apt tools expertly wielded in creating accounts of nature that fascinate liy their almost uncanny accuracy and precise deductions. Here is nature writing at its most original. And the full flavors of the land- scape, the mood of the moment, the behavior and the habits of the wild life, the philos- ophies of the author, become shared experiences to remember. The hook deals with an English summer and with English birds. There are especially memorable passages on the Nightjar iCaprimiilgus europaeiis) , on the Sparrow Hawk (Accipiter nisus) and the Kestrel {Falco tinnunculus) , a great deal of highly revealing and unsentimental interpretations on the predations of hawks and owls, amazingly closely observed in minutest details. If at the start the reader is left slightly perplexed, the book grows on him, and he closes it at the end with the distinct feeling of having been given a remarkably penetrating and enchanting look at the wonders of nature by a fine observer and naturalist. “Suddenly he looks up, scanning my dark shape with bland indifference. Under the pale sunset glow that shines beyond the stained-glass sky of the hawthorns, the owl has the face of a saint. A mouse squeeks, a frail bud of sound, deep in the long grass. The owl stops abruptly, wheeling aside, like a white cloth flicked across my eyes. He thumps down, and the grass swirls open beneath his spreading wings. The mouse is dead.” — Louise de K. Lawrence. December 1970 Vol. 82, No. ORNITHOLOGICAL LITERATURE 473 The Avifauna of Northern Latin America: A Symposium held at ihe Smithsonian In- stitution 13-15 April 1966. Edited hy Helmut K. Buechner and .limmie H. Buechner. Smithsonian Institution Press, Washington, D.C. 1970: 8 X 10% in., 119 pp., 4 figs. (Obtainable from the Superintendent of Documents, U. S. Government Printing Office). $3.25. In our preoccupation with the manifold threats to bird habitats and environment in North America it is easy to forget that something over 200 species of birds which nest in the United States migrate through, or winter in, Alexico, Central America, and the Caribbean. Conservation and protection measures north of the Rio Grande will he of little avail to these species if their wintering habitat disappears south of that river. It has been suggested, for example, that the population of Kirtland’s Warbler is controlled, not by circumstances in northern Michigan, but hy the amount of available wintering territory in the Bahamas. In 1966, at the suggestion of the late William Vogt, the Smith- sonian Institution sponsored a symposium addressed to the general problem of the status of the birds of northern Latin America, and we now have at hand the proceedings of that symposium. Papers were given concerning the birds of Alexico (A. R. Phillips, R. Hernandez Corzo) . Guatemala (J. A. Ibarra), British Honduras (S. M. Russell), Honduras (B. L. Monroe, Jr.), Nicaragua IT. R. Howell), Panama (E. Eisenmann), Colombia (A. Olivares, F. C. Lehmann), and Venezuela (W. H. Phelps, Jr.). General papers were given by L. R. Hol- dridge, John W. Aldrich and Chandler S. Robbins, William Vogt, and Marston Bates. At the close of the conference a set of suggestions and resolutions was drawn up. The recurring theme of all the papers, and the discussion of them, was the rapid de- struction of the tropical forest habitats under the increased pressure of population growth. Many tropical species are facing extirpation, and even extinction in a short time if this continues. Indeed, some highly endemic species may already have become extinct. There was general agreement among the participants that the North American migrants were in no great danger from these changes. The only bright spot in the picture was the par- ticipation in the symposium of several Latin American biologists, who pointed out that thoughtful people in these countries and their governments are not unaware of the prob- lem. Tire great difficulties of remedying the situation in face of the pressures for more agricultural land and the need for much education of the local people were stressed. This volume makes interesting, although gloomy, reading. It is to be regretted that publication of the material comes four years after the symposium. Although there is a brief appendix outlining a few developments to 1969, one cannot help hut wonder, in view of the rates of population growth and of deforestation described in the papers, if most of the matter discussed is not already greatly outdated. — George A. Hall. RECENT PUBLICATION Check-list of the Birds of New Mexico. By John P. Hubbard, 1970. 108 pp., 3 maps. New Mexico Ornithological Society (Box 277, Cedar Crest, N.M. 87008), Puhl. 3. $2.50, post-paid. THE WILSON ORNITHOLOGICAL SOCIETY President First Vice-President Second Vice-President Secretary Treasurer Editor Officers, 1970 William W. H. Gunn Pershing B. Hofslund Kenneth C. Parkes Jeff Swinebroad William A. Klamm George A. Hall Additional Members of the Executive Council C. Chandler Ross Elective Members Ernest P. Edwards Elden W. Martin Albert F. Ganier Margaret M. Nice George M. Sutton S. Charles Kendeigh Olin Sewall Pettingill, Jr. Phillips B. Street Past Presidents Maurice G. Brooks Walter J. Breckenridge John T. Emlen, Jr. Lawrence H. Walkinshaw Trustees Edward L. Altemus Harold F. Mayfield Phillips B. Street Roger Tory Peterson Aaron M. Bagg H. Lewis Batts. Jr. Allan Crawford, Jr. Editorial Staff of The Wilson Bulletin Editor George A. Hall Editorial Advisory Board William C. Dilger Douglas A. James William A. Lunk Andrew J. Meyerriecks Helmut C. Mueller Robert W. Nero Kenneth C. Parkes Glen E. Woolfenden Annual Meeting Conservation Endowment Library Membership Nominating Research Student Membership Ornithological Literature Editor Peter Stettenheim Chairman of Committees M. Wilson Gaillard - — H. Lewis Batts, Jr. Aaron M. Bagg William A. Lunk Pershing B. Hofslund Phillips B. Street Val Nolan, Jr. — - Douglas A. James 474 INDEX TO VOLUME 82, 1970 This index includes, in addition to the names of genera, species, and authors, references to the following topics: Anatomy, hehavior, lireeding, clutch size, distribution, ecology, eggs, evolution, food habits, fossils, habitat, hatching, hybridization, incubation, measure- ments, migration, mortality, molts and plumages, navigation, nesting, nesting success, parasitism, pesticides, physiology, populations, predation, sex ratios, taxonomy, territory, loice, and weights. Also included are references of biological significance to reptiles and mammals. The names of new forms described in this volume are printed in boldface type. Acanthi's flamniea, 284 Accipiter striatus velox, 92 Aegolius acadicus, 374 Aethia cristatella, 289, 291, 292 pusilla, 289, 290, 291 pygmaea, 291 Agelaius phoeniceus, 83, 160, 283, 294 Agriocharis atiza, 218 crassipes, 217, 218 leopoldi, 217, 218 ocellata, 218 progenes, 214, 217, 218 AIca torda, 289, 292 Aldrich, John W., and Kenard P. Baer, Status and speciation in the Mexican Duck (Anas diazi) , 63-73 Alectoris sp., 282 Alopex lagopus, 134 Amadon, Dean, see Brown, Leslie, and Ameiva j estiva, 98 Ammodramus savannarum, 376 Ammospiza maritima, 225 m- macgillivraii, 164 7Ji. pelonota, 163 nigrescens, 158, 161, 164 Anas carolinensis, 461 diazi, 63, 68, 71, 72 d. diazi, 68, 69 d. novemexicana, 63, 68, 69 discors, 333, 334, 447 platyrhynchos, 11, 63, 68, 71, 72, 95, 323- .324, 447, 461 Tiihripes, 70 strepera, 96, 387 Anatomy, 219-220; 289-293 Anderson, Daniel W., see Nellis Carl M. and Anderson, Daniel W., and Joseph J. Hickey, Oological data on egg and breeding characteristics of Brown Pelicans, 14-28 Anhinga anhinga, 458 Anhinga, 458 Anolis limijrons, 98 Anser albijrons, 6, 421 a. frontalis, 420-426 a. gambelli, 420-426 Aphelocoma coerulescens, 282 uhramarina, 282 Aratinga canicularis, 280, 282 Archilochus alexandri, 225 Ardea cinerea, 20 Arenaria interpres, 99 Arremenops conirostris, 284 Asio flammeus, 99, 134 Ay thy a, 11 Aytliya ajjinis, 387 aniericana, 320, 447 Auklet, Crested, 289 Least, 289 Parakeet, 289 Austin, Elizabeth S. (Ed.), Frank M. Chapman in Florida: His Journals and Letters, reviewed, 238 Baker, J. A., The Hill of Summer, re- viewed, 472 Baer, Kenard P., see Aldrich, John W., and Bauer, Kurt M., and Urs N. Glutz von Blotzheim, Handhuch der Vogel mit- teleuropas. Vol. 1, reviewed, 112 Bauer, W., 0. van Helversen, M. Hodge,, and J. Martens. Catalogus Faunae Graeciae, reviewed, 314 475 476 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Banks, Richard C., Molt and taxonomy of Reddrreasted Nuthatches, 201-205; Re- evaluation of two supposed hybrid birds, 331-332 Bedard, Jean, Historic naturelle du Code, AIca tOTcla, L., dans le Golfe Saint- Laurent, Province de Quebec, Canada, reviewed, 314 Behavior, 29-52, 53-62, 74-78, 96-97, 98-99, 99, 99-100, 100, 101, 120-121, 167-176, 177-183, 184-188, 189-200, 220, 221- 222, 222-223, 225, 225-226, 227, 228, 268-278, 279-288, 310-314, 315, 323- 324. 324-325, 326-327, 327-328, 330- 331, 391-399, 427^34, 446-447, 450, 454, 455, 461-462, 463, 465 Bergman, Robert D., Peter Swain, and Milton W. Weller, A comparative study of nesting Forster’s and Black Terns, 435-444 Blackbird, Red-winged, 83, 160, 294-303 Bohwhite, 243, 244, 248, 256, 262, 265 Bolen, Eric, and John J. Beecham, Notes on the foods of juvenile Black-bellied Tree Ducks, 325-326 BoinbyciJIa cedrorum, 81, 283, 375, 465 Ronasa unibellus, 310 Borth, Melvin, see Dunstan, Thomas C., and Rrachyrhamphus brevirostre, 290. 291 marmoratum, 290, 291 Rranta bernicla, 6, 383 canadensis, 6, 334 c. parvipes, 422 nigricans, 6. 383 Brant, 6. 9, 11 Black. 6, 9 Breeding. 5-13, 14-28, 95, 96, 141-142, 225, 383-390, 445-457 Brotogeris jugiiktris, 282 Brown. Leslie, and Dean Amadou, Eagles, Hawks and Falcons of the World, re- viewed, 230-235 Brown, Richard D., Yellowthroat caught in common burdock, 464-465 Bruning, Donald, Conjoined twin Darwin’s Rhea, 219-220 Bubo rirginianus, 374, 462 Bubulcus ibis, 458 Bucepha/a albeola, 334 Buechner, Helmut K., and Jimmie H. Buechner, editors. The Avifauna of Northern Latin America, reviewed, 473 Buechner, Jimmie H., see Buechner, Helmut K., and Bufflehead, 334 Buhner, Walter, First specimens of Chest- nut-collared Longspur and Little Cull from Connecticut, 226-227 Bunting, Indigo, 80, 81 Lark, 376, 465-166 Ortolan, 160 Buteo janiaicensis, 96 lineatus, 465 platypterus, 221, 327 regalis, 374 swainsoni, 96 Butorides virescens, 282 Calaniospiza melanocorys, 376, 465 Calcarius ornatus, 226 CalociUa forniosa, 282 Campephilus irnperialis, 115, 121, 123, 124, 125, 127, 128 magellanicus, 115, 117, 124, 127, 128 rnelanoleucus, 126 principcdis, 115, 117, 121, 122, 123, 124, 125, 127, 128 robustus, 126 Campochaera sloetii, 40 Campylorhynchus brunneicapiUus, 161, 282, 285 Caprimiilgiis caroHnensis, 329 Carduelis carduelis, 284 Cardinal. 77, 83-91, 330 Caribou, 134 Carpodacus purpureus, 284 m-exicanus, 270, 315 Casnierodins albus, 458 Catbird, 74, 76, 78, 81, 330, 375, 379 Calhartes aura, 462 Centrocercus phasianus, 217 C.enturus caro/inits, 463 Cerorhinca monocerata, 290, 291 Cepphus cohimba, 289, 291, 292 gryJJe, 289, 291 Chaffinch, 60, 281 (iharadrius pecuarius, 100 voci ferns, 284 Channosyna placenlis, 31, 32, 33, 34, 35, 44, 45, 49 December 1970 Vol. 82, No. 4 INDEX TO VOLUME 02 4-77 р. placentis, 39 pul ch el I a, 36, 39, 45 Chen caerulescens, 6 hyperborea, 6 rossii, 5 Chickadee, Black-capped, 53-62, 331, 374, 427-434, 465 Carolina, 331, 427, 431, 433 Mountain, 427, 429, 431, 432 Chlidonias niger, 435 Chloris chloris, 284 Chondestes grammaciis, 304, 376 Chordeiles minor, 221, 374 Christman, Gene M., see Orians, Gordon H., and Chuck-will’s-widow, 329 CicinnuTiLS regius, 42 Ciconia mcdtha, 334 Circus cyaneus, 98 Citellus armatus, 271 tridecemlineatus, 261 Clark, George A., Jr., Avian hill-wiping, 279-288 Clangula hyemalis, 383 Clench, Mary Heimerdinger, review hy, 109-111 Clutch size, 5-13, 15, 95, 253-255, 304-309, 316, 441, 451, 452, 453 Cochran, William W., see Kjos, Charles C., and Coccothraustes coccothraustes, 284 Coccyzus erythrophthalmus, 374 Colaptes auratus, 81, 282, 329 cafer, 374 pitius, 115, 117 Colinus virginianus, 243, 282 Coluber constrictor, 262, 306, 330 с. anthicus, 330 Columba livia, 189, 284, 427 Condee, Ralph W., Tlie winter territories of Tufted Titmice, 177-183 Condor, California, 158 Contopus sordidu/us, 374 virens, 81 Coot, American, 445, 457 European, 447 Red-fronted, 454 Red-gartered, 454 Coracina boyeri, 40 caeruleogrisea, 40 Coragyps atratus, 462 Corvus brachyrhynchos, 98, 261 corux, 386 jrugilegus, 282 Cowhird, Brown-headed, 74-78, 260, 304- 309 Crow, Common, 98-99, 261 Cuckoo, Black-billed, 374 Cyanocitta cristata, 101, 282, 285, 330 stelleri, 282 Cyclorrhynchus psittacula, 289, 290, 291, 292 Cygnus olor, 324 Davis, Frederic W., Territorial conflict in the American Woodcock, 327-328 Davis, G. James, Seasonal changes in flock- ing behavior of Starlings as correlated with gonadal development, 391-399 Demaree, Salome Ross, Nest-huilding, in- cubation period, and fledging in the Black-chinned Hummingbird, 225 Dendragapus obscurus, 83 Dendrocopos lignarius, 115, 117, 120 pubescens, 374 Dendrocygna autumnalis, 325 Dendroica audiiboni, 315, 355-369 coronata, 355-369 c. audiiboni, 367 c. goldmani, 355, 357, 366, 368 c. hooveri, 355, 362, 369 c. memorabilis, 355, 366, 367, 368 c. nigrif rolls, 355, 366, 367, 368 discolor, 281, 283 fused, 81 kirtlandii, 57, 76, 283 occidental is, 464 pensylvanica, 81 petechia, 174, 281, 283, 375 Diamond, Jared M., see Terl)orgh. John, and Dicaeum geelvinkianinn, 43 Dicroslonyx groenlandicus, 132, 137. 155 Didelphis marsupialis, 262, 463 Diphyllodes magni ficus, 41, 47 Distribution. 64-67, 92-95, 102-103. 223- 224, 226-227, 329, 366, 421, 422, 4C)2, 464, 465-466 Dixon, Keith L., and Raymond A. Stefanski, An appraisal of the song of the Black- capped Chickadee, 53-62 478 THE WILSON BULLETIN December 1070 Vol. 82, No. 4 Domicella lory, 39 Donaldson, Grace, see Hays, Helen, and Dove, Mourning, 96, 284, 374, 377, 378, 380, 381 Rock, 284 Dovekie, 289 Dow, Douglas D., Indexing population - densities of the Cardinal with tape- recorded- song, 83-91 Drewien, Rod C., and Larry F. Fredrickson, High density Mallard nesting on a South Dakota Island, 95-96 Dryocopus lineatus, 117 /. si mil is, 92 pileatus,\ll , 118, 124 Duck, Black, 70, 71 Black-hellied Tree, 325-326 Black-headed, 451 Mexican, 63-73 Ruddy, 447 Dwcida rufigaster, 39 Duinetella carolinensis, 74, 81, 282, 330, 375 Dunstan, Thomas C. and Melvin Borth, Suc- cessful reconstruction of active Bald Eagle nest, 326-327 Dusi, Julian L., and Rosemary T. Dusi, Nesting success and mortality of nestlings in a Cattle Egret Colony, 458-4<50 Dusi, Rosemary T., see Dusi, Julian L.. and Eagle, Bald, 20, 220, 326-327 Easterla, David A., Eirst nesting colonies of the Lark Bunting in Missouri, 465- 466; Hermit Warbler in Missouri, 464 Ecology. 29-52, 79-82, 115-120, 158-166, 243-267, 370-382, 466 Edolisoma montaniim, 40 Eggs. 14^28, 77-78, 103, 123, 255 Egret, Cattle, 458-460 Common, 458 Snowy, 458 Eider. Steller’s, 147 Eisenmann, Eugene, review l)y, 106-109 Elanoides jorficatus, 462 Elaphe obsoleta, 306, 329 Elgas. Boh, Breeding populations of Tule White-fronted Ceese in northwestern Canada, 420-426 Emberiza hortulana, 160 Empidonax difficilis, 317 minimus, 81, 374 traillii, 282 Enders, Frank, The double-scratch in the Seaside Sparrow, 225 Endomychura craveri, 290 hypoleuca, 290, 291 Eremophila alpestris, 226 Erolia alpiria, 134 melanotos, 134 Erithacus rubecula, 283 Eudocimus albus, 458 Eiudynamis scolopacea, 40 Evans, Roger M., Oldscjuaws nesting in as- sociation with Arctic Terns at Church- ill, Manitoba, 383-390 Evolution, 5-13, 285-286 Ealco columbarius, 374 sparverius, 97, 374 Feduccia, J. Alan, The avifauna of the Sand Draw local fauna (Aftonian) of Brown County, Nebraska, 332-334 Ficedula hypoleuca, 283 Ficken, Millicent S., see Ickes, Roy A., and — Finch, House, 270, 274, 276 Fisk, Erma J., Common Crackle kills Cedar Waxwing in air, 465 Flicker, 81 Chilean, 115 Red-shafted, 374, 379 Yellow-shafted, 329-330, 463 Florida caerulea, 458 Flycatcher, Crested, 81 Fork-tailed, 92 Least, 80, 81, 374 Western, 317 Vermilion, 315-319 Food Habits, 29-52, 97-98, 99, 101, 101- 102, 136-138, 184-188, 206-213, 222- 223, 228, 325-326, 462-463 Fossils, 214-218, 332-334 Fox, Arctic, 134 Gray, 262 Red, 261 Fratercula arctica, 290 corniculata, 289, 290, 291 Fredrickson, Larry F., see Drewien, Rod C., and December 1970 Vol. 82, No. t INDEX TO VOLUME 82 479 Fredrickson, Leigh H., Breeding biology of American Coots in Iowa, 445-457 Fringilla coelebs, 60, 281, 284 montefringilla, 284 Fulica americana, 445 armillata, 454 atra, 447 rufi irons, 454 Gadwall, %, 387 Galliis gallus, 282, 427 Gannet, 158 Geothlypis trichas, 281, 283, 375, 464 Gerygone chloronata, 35, 40, 47 palpebrosa, 40 Giles, Robert H., editor. Wildlife Manage- ment Techniques, reviewed, 470-471 Glutz von Blotzlieim, Urs. N., see Bauer Kurt AL, and Glycichaera fallax, 34, 42 Goldeneye, Barrow’s, 220 Goldfinch, 277 American, 375, 379 Goose, Blue, 6, 9, 11 Canada, 6, 334 Lesser Snow, 6 Ross’, 5-13 White-fronted, 6, 9, 420M26 Gould, John, Birds of Asia, reviewed, 314 Grackle, Boat-tailed, 472 Common, 465 Grebe, Horned, 334 Greenewalt, Crawford H., Bird Song: Acoustics and Physiology, reviewed, 235-237 ; How Birds Sing, reviewed, 235-237 Grisez, Ted, A White-throated Sparrow nests in western Pennsylvania, 102-103 Grosbeak, Black-headed, 94 Rose-breasted, 81, 280 Ground Squirrel, Uinta, 271 Thirteen-lined, 261 Grouse, Blue, 83 Ruffed, 206, 310-314 Sage, 217 Sbarp-tailed, 221-222 Gull, Black-headed, 281 Glaucous, 134, 151 Herring, 20, 189-200, 386, 389, 464 Laughing, 222 Little, 226-227 Ring-billed, 189, 196, 222-223 Gunn, William W. H., review by, 235-237 Guillemot, Black, 289 Pigeon, 289 Gymnocorvus tristis, 41, 47 Gymnophaps, cdbertisii, 39 Gymnopithys, 282 Gymnostinops montezuiiia, 94 Habia gutturalis, 284 rubica, 284 Habitat, 115, 130-132, 160, 370-382, 436- 439, 466 Haliaeetus leucocephalus, 20, 220, 326 Hall, George A., review by, 473 Hammer, Donald A., Trumpeter Swan carrying young, 324^325 Hanson, Hugh, see Taylor, Walter Kingsley and Hartzler, Jonathan E., Winter dominance relationship in Black-capped Chicka- dees, 427-434 Hatching, 289-293, 318 Haverschmidt, F., Ruddy Turnstones mak- ing use of Yellow-crowned Night Herons for food-finding, 99; Barn Owls hunting by daylight in Surinam, 101 ; Rufous-crowned Tanagers feeding on fruitbowl, 228 Hawk, Broad-winged, 227, 327 Marsh, 98-99 Pigeon, 374, 379 Red-shouldered, 465 Red-tailed, 96-97 Rough-legged, 374, 379 Sharp-shinned, 57, 92 Sparrow, 97-98, 374, 379 Swainson’s, 96-97 Hays, Helen, Common Terns pirating fish on Great Gull Island, 99-100 Hays, Helen, and Grace Donaldson, Sand- kicking camouflages young Black Skimmers, 100 Hein, Dale, Dust-bathing sites selected by Ruffed Grouse, 310-314 Heilman, Geoffrey, Bankers, Bones, and Beetles, reviewed, 239 Hehnilheros verniivorus, 228 Herbert, A. D., Spatial disorientation in in birds, 400-419 480 THE WILSON BULLETIN December 1970 Viil. 82, No. I Heron, Little Blue, 458, 459 Yellow-crowned Niglrt, 99 Heteronetta atricapilla, 451 Hickey, Joseph J., editor. Peregrine Falcon Populations, reviewed, 105-106; see Anderson, Daniel W., and Hickman, Graham C., Egg transport re- corded for the Red-bellied Woodpecker, 463 Hippolais icterina, 283 Hinindo rustica, 463 Hodge, M., see Bauer, W., and Hoff, C. Clayton, and Marvin L. Riedesel, editors. Physiological systems in semi- arid environments, reviewed, 237-238 Holcomb, Larry C., and Gilbert Twiest, Growth rates and sex ratios of Red- winged Blackbirds, 294-303 Horak, Gerald L., A comparative study of tbe foods of the Sora and Virginia Rail, 206-213 Hubbard, John P., Geographic variation in the Dendroica coronata complex, 355- 369 Hudson, J. W., review by, 237-238 Hummingbird, Black-chinned, 225 Rufous, 285 Hyliridization, 69, 71, 97, 331-332, 461-462 Hylocichla fuscescens, 226, 375 guttata, 103, 226 minima, 226 mustelina, 81 ustulata, 226, 375 lliis, White, 458 Ickes, Roy A., and Millicent S. Ficken, An investigation of territorial behavior in the American Redstart utilizing re- corded songs, 167-176 Icterus bullockii, 375 ga/bula, 94, 184, 283, 375 Incubation, 225, 441-442, 454 Iridoprocne bicolor, 282 Ipocrantor, 127 Jackson, Jerome A., Predation of a Black Rat Snake on Yellow-shafted Flicker, 329-330 Jaeger, Parasitic, 134, 386, 387, 389 Bomarine, 130-157 Jay, Blue, 101-102, 330 Jenkins, Robert E., Food habits of winter- ing Sparrow Hawks in Costa Rica, 97-98 Jenkinson, Marion Anne, see Mengel, Robert M., and — Johnston, David W., High density of birds breeding in a modified deciduous forest, 79-82 Junco hyemalis, 81, 103, 284 oreganus, 276 Junco, Oregon, 276 Slate-colored, 80, 81, 103 Killdeer, 284 King, Warren B., review by, 471-472 Kingbird, Eastern, 374, 379 Western, 93, 374, 379 Kinglet, Golden-crowned, 464 Kish, Frank, see Wolhuter, Bruce R., and Kite, Swallow-tailed, 462 Kittiwake, Black-legged, 137 Kjos, Charles G., and William W. Cochran, Activity of migrant thrushes as deter- mined by radio-telemetry, 225-226 Klimstra, W. D., see Roseberry, John L., and Lagopus scoticus, 282 Lalage leucomela, 40 Lampropeltis caligaster, 262 Lancaster, D. A., review by, 470-471 Lanins excubitor, 283 ludovicianus, 283, 375, 466 Lark, Horned, 226 Larus argentatus, 20, 189, 284, 386, 464 atriciUa, 222 delawarensis, 189, 222 hyperboreus, 134 minutus, 227 ridibundus, 281, 282 Lateralhis, 333, 334 Lawrence, Louise de Kiriline, review by, 341-342, 472 Leberman, Robert C., review by. 339-341 Lemming, Collared, 132 Brown, 130-157 Lemmus trimucronatus, 130-157 Leucophoyx thula, 458 Limnothlypis swainsonii, 228 Lonchura cucuUata, 283 punctulata, 283 striata, 283 December 1970 Vol. 82, No. 4 INDEX TO VOLUME 82 Longspur, Chestnut-eollaied, 226-227 Lophorina superba, 41 Loriculus aiirantiijrons, 40, 44 galagulus, 282 vernalis, 282 Loxia curvirostra, 284 Lunda cirrhata, 291 Luscinia megarhynchos, 283 Machaerirhynchus flaviventer, 31, 41 Macropygia amboinensis, 39 nigrirostris, 39 Magpie, Black-billed, 374, 379 Maher, William J., The Pomarine Jaeger as a Brown Lemming predator in northern Alaska, 130-157 Mallard, 11, 63, 68, 69, 71, 72, 95-96, 323- 324, 447, 461-462 Mareca ctmericana, 464 Margarops fuscatus, 464 Martens, J., see Bauer, W., and Martin, Larry D., and James Tate, Jr., A new turkey from the Pliocene of Ne- hraska, 214-218 Meadowlark, Eastern, 164, 243-267 Western, 243, 255, 373, 375, 377, 381 Meanley, Brooke, Method of searching for food hy the Swainson’s Warliler, 228 Measurements, 14^28, 69, 77, 118, 223, 294-.300, 334, 360-361, 424 Melanochuris longicauda, 43 striativenlris, 43 versteri, 43, 46 Meleagris altu, 218 gcdlopavo, 218, 465 Melidectes torquatus, 31, 36, 42, 46, 50 Melilestes megarhynchus, 42, 46 Meliphaga orien tails, 50 Meliphaga spp., 31, 33, 34, 35, 36, 37, 43, 44, 45, 47, 50 Melipotes fumigatus, 42, 50 Melopsittacus undulatus, 282 Melospiza georgiana, 284 nielodia, 60, 246, 284, 285 Mengel, Robert M., and Marion Anne Jenkinson, Parasitism l)y the Brown- headed Cowhird on a Brown Thrasher and a Catbird, 74-78 Mephitis mephitis, 261 Merops ornatus, 40 481 Merrell, Theodore R., Jr., A swimming Bald Eagle, 220 Michael, Edwin D., Wing flashing in a Brown Thrasher and Catbird, 330-331 Microtus calijornicus, 153 oeconomus, 133, 137 ochrogaster, 262 pennsylvanicus, 261 Migration, 225-226, 323-324 Miley, Theodore R., Males in breeding plumage of the races of the Dendroica coronata complex, watercolor by, facing page 355 Alilne, Lorus, and Margery Milne, Birds of North America, reviewed. 469-470 Milne, Margery, see Milne Lorus, and Mimas polyglottos, 282, 330 Mino dumontii, 37, 41, 47 Mockingbird, 330 Molo thrus a ter, 74, 260, 283, 285, 304 Molts and plumages, 201-204, 298-299, 320-323 Monroe, Burt L., Jr., A distributional study of the birds of Honduras, reviewed, 106-109 Mortality, 405-407, 415-418, 458-460 Morton, Eugene S., Chuck-will s-widow in Connecticut, 329 Mueller, Helmut C., Circle-soaring by migrating nightbawks, 227 Murre, 18, 292 Common, 289 Thick-billed, 289 Murrelet, Kittlitz’s, 292 Mascivora tyrannus, 92 Mas tela erminea, 261 rixosa, 134, 155 Myiarchus criiiitus, 81 Myzomela cruentata, 31, 32, .33, 35, 36, 42 eques, 31, 33, 35, 42 nigrita, 31. 32, 33, 35, 42. 45. 46 obscurus, 47 rosenbergii, 31, 36, 42 Navigation, 189-200, 400-419 Nectarina sericea, 47 Nellis, Carl H.. James ,1. Zohrer, and Daniel W. Anderson. Mallard-Creen- winged Teal associations in southern Wisconsin, 461-462 482 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Nero, Robert W., Sharp-tailed Grouse gives aggressive display to automobiles, 221- 222; review by, 336-338 Nesting, 5-13, 95-96, 102-103, 119, 225, 243-267, 304-305, 315-319, 326, 370- 382, 383-390, 435^44, 445-457, 463, 463-464, 465-466 Nesting success, 255-265, 304—309, 387, 442, 458-460 Newman, George A., Cowbird parasitism and nesting success of Lark Sparrows in southern Oklahoma, 304—309 Nightbawk, Common, 227, 374 Nothoprocta cinerascens, 282 Nuthatch, Red-breasted, 201-205 White-breasted, 81, 286 N yctanassa violacea, 99 Nyctea scandiaca, 134 Oedistoma pygmaeum, 31, 32, 33, 34, 35, 42, 47, 49 Oldsquaw. 383-390 Olor buccinator, 324, 334 Opopsitta diophthalma, 40 gulielmi 111, 40 Oporornis jorniosus, 228 Opossum, 262, 463 Oreornis obscurus, 31, 32, 33, 34, 35, 42, 47, 50 Orians, Gordon H., and Gene M. Christ- man, A comparative study of the be- havior of Red-winged, Tricolored, and Yellow-headed Blackbirds, reviewed, 336-338 Oriole, Baltimore, 94, 184-188, 375, 379 Bullock’s, 375, 379 Oriolits szalayi, 41, 47 Oropendola, Montezuma, 94 Otiis asio, 223-224, 330 a. f/oridanus, 223 a. gi/mani, 223 flanuneolus, 223-224 scops, 223 spHocephalus, 223 Irichopsis, 223 Ovenhird, 77, 80, 167, 228, 248 Owl, Barn, 101 Burrowing, 334 Flammulated, 223-224 Great Horned, 95. 98- 99, 374, 379 Sand Draw Burrowing, 333 Saw-whet, 374 Screech, 330 Short-eared, 99, 134 Snowy, 134, 151 Oxyura jamaicensis, 447 P achy care flavogrisea, 41 Pachycephala rujiventris, 41 soror, 41 Paradisaca apoda, 31, 42, 47 raggiana, 282 rudolphi, 42 Parapavo californicus, 218 Parasitism, 74-78, 99-100, 260-261, 307- 309 Parkes, Kenneth C., On the validity of some supposed “first state records” from Yucatan, 92-94; review by, 230- 235 Parotia carolae, 282 Paras atricapillus, 53, 59, 60, 282, 331, 374, 427, 465 atricapillus X P- gambeli, 331 bicolor, 81, 177 carolinensis, 56, 282, 331, 427 caeruleus, 271, 430 gambeli, 331, 427 inornatus, 60 major, 282, 429 montanus, 331 Passer domesticus, 268, 283 Passerina cyanea, 81 Peakall, David B., review by, 105-106 Pearse, Theed, Birds of the Early Explorers in the North Pacific, reviewed, 471-472 Pediocetes phasianellus, 221 Pelecanus erythrorhynchos, 15 occidentalis, 14 o. calijornicus, 16, 17, 18, 21, 22 o. carolinensis, 16, 17, 18, 21, 22 o. occidentalis, 16, 22 Pelican, Brown, 14—28 White, 15 Pel tops montanus, 31, 41 Pesticides, 19-21 Petrochelidon pyrrhonota, 374 Pettingill, Eleanor Rice, review by, 238 Petlingill, Olin Sewall, Jr., review by, 240, 314, 469-470 Pewee, Western Wood, 374 Wood, 81 December 1970 Vol. 82, No. 4 INDEX TO VOLUME 82 I f>9 loo Phasianus colchicus, 96, 374 Phalarope, Red, 136 Phalaropus fulicarius, 134 Pheasant, Ring-necked, 96, 374 Pheucticus ludoviclanus, 80, 81, 280, 284, 285 m. melanocephalus, 94 Phil oh el a minor, 160, 327 Phloeoceastes guatemalensis, 121, 124, 125, 126, 127 guayaquilensis, 127 haematogaster, 127 leucopogon, 121, 125, 126, 127 melanoleucos, 121, 124, 125, 126 pollens, 127 robustus, 121, 125, 126, 127 rubricollis, 122, 128 Phoebe, Eastern, 77, 81, 463-464 Phoenicurus phoenicurus, 283 Phylloscopus trivirgatus, 40 trochilus, 160 Physiology, 294^303, 400-419 Pica pica, 374 Pipilo erythrophthalmus, 60, 77, 81 Piranga ludoviciana, 94 olivacea, 81 Pitouhui dichrous, 41, 45 Plautus alle, 289 Ploceus melanocephalus, 283 Podiceps auritus. 334 Poephila bichenovi, 279, 283 guttata, 281, 283 Polysticta stelleri, 147 Pooecetes gramineus, 376, 465 Populations, 23-26, 66, 67, 79-82, 88-90, 95-%, 138-141, 158-166, 370-382, 391- 399 PoTzana Carolina, 206 Predation, 57, 95, 130-157, 261-263, 305- 307, 329-330, 386-387, 465 Proagriocharis gen. nov., 214 keniballensis. 215, 216, 217 Psittaculirostris desmarestii, 31, 40, 44, 45 Pterocnemia pennata, 219 Ptilinopus perlatus, 39 pulchellus, 39 ornatus, 39 rivoli, 39 superbus, 39 Ptychoram.phus aleulica, 290, 292 Publication Notes and Notices, 239, 314, 319 Puffin, Horned, 289, 291 Pycnopygius cinereus, 43, 45, 46, 50 ixoides, 34, 35, 43, 47, 49, 50 Pyrocephalus riibinus, 315 Pyrrhula pyrrhula, 284 Quail, California, 206 Quelea quelea, 272, 274 Quiscalus quiscula, 283 Racer, Blue, 262, 306 Rail, Virginia, 206-213 Rail us limicola, 206 Rangifer caribou, 134 Rat, Cotton, 263 Razorbill, 289 Raven, Common, 386, 387, 389 Redhead, 320-323 Redstart, American, 167-176, 375 Regulus satrapa, 464 Reilly, Edgar M., Jr., The Audubon Illus- trated Handbook of American Birds, reviewed, 109-111 Rhea, Darwin’s, 219-220 Richmondena cardinalis, 77, 83, 330 Riedesel, Marvin L., see Hoff, C. Clayton, and Rissa tridactyla, 137 Robin, 79, 80, 81, 82, 375, 378, 379 American, 60 Roseberry, John L., and W. D. Klimstra, The nesting ecology and reproductive performance of the Eastern Meadow- lark, 243-267 Ryder, John P., A possible factor in the evolution of clutch size in Ross’ Goose, 5-13 Rynchops nigra, 100, 222 Salpinctes obsoletus, 375 Sandplover, Kittlitz, 100 Sayornis phoebe, 77, 81 Saxicola rubetra, 283 Scaup, Lesser, 387 Schroeder, Albert H., editor. Collected papers in honor of Lyndon Lane Har- grave, reviewed, 239-240 Scolopax rusticola, 327 Sealy, Spencer G., Egg-teeth and hatching methods in some alcids, 289-293 Sebeck, Thomas A., editor. Animal Com- 484 THE WILSON BULLETIN December 1970 Vol. 82, No. -1 munication : Technique of Study and Results of Research, reviewed, 240 Seiurus aurocapillus, 77, 80, 167, 228, 248, 283 motacilla, 228 noveboracensis, notabilis, 93 n. noveboracensis, 93 n. iiliginosus, 94 Selasphorus rufus, 285 Serinus, 284 canaria, 285 Service, William, Owl, reviewed, 342 Setophaga ruticilla, 167, 283, 285, 375 Sex Ratios, 294-303 Sharp, Brian, A population estimate of the Dusky Seaside Sparrow, 158-166 Short. Lester L., The habits and relation- ships of the Magellanic Woodpecker, 115-129 Shrike, Loggerhead, 375, 378, 466 Sialia sialis, 283 Sigmodon hispid us, 263 Siskin, Pine, 464, 465 Sitagra melanocephcdus, 283 Sitta canadensis, 201, 205 c. canadensis, 204, 205 c. clariterga, 201, 204, 205 carolinensis, 81, 286 Skaar, P. D., Birds of the Bozeman Latilong, reviewed, 319 Skimmer, Black, 100, 222 Skunk, Striped, 261, 262 Smithe, Frank B., Las Aves de Tikal, re- viewed, 314 Snake, Black Rat, 306, 329-330 Carter, 95, 261 Prairie King, 262 Sora, 206-213 Southern, William E., Marsh Hawk chases crows mobbing owl, 98-99; En route behavior of homing Herring Culls as determined by radio-tracking, 189-200 Sparrow, Brewer’s, 376, 377, 380, 381 Chipping, 81, 376, 378 Dusky Seaside, 158-166 Cohlen-crowned, 332 Crasshopper, 376, 379 House, 268-278, 463, 465 Lark, 304-309, 373, 376, 377, 378, 380, 381 New Smyrna Seaside, 163 Seaside, 225 Song, 60, 246, 259 Vesper, 376, 465 White-crowned, 332 White-tliroated, 102-103, 332 Speotyto cunicularia, 333, 334 c. intermedia, 333, 334 c. megalospeza, 334 megalospeza, 333, 334 Sphyrapicus varius, 282 Spiniis pinus, 464, 465 tristis, 277, 284, 375 Spofford, Sally H., review by, 342 Spizella arborea, 284 breweri, 376 passerina, 81, 284, 376 Starling, 269, 276, 375, 379, 391-399, 463 Stefanski, Raymond A., see Dixon, Keith L., and Sterna douga/Iii, 99 jorsteri, 435 hirundo, 99, 284, 464 paradisaea, 99, 383 sandvichensis, 284 Stercorarius parasiticus, 134, 386 pomarinus, 130 Sturnella inagna, 164, 243, 247. 257. 260 negJecta, 243, 237, 257. 260. 375 Sturnus vulgaris, 269, 283, 375, 391 Svensson, Lars, Identification Cuide to European Passerines, reviewed. 319 -Swain, Peter, see Bergman. Robert 1).. and Swallow, Barn, 463-464 Cliff, 374 Violet-green. 93, 315 Swan, Mute. 324 Trumpeter, 324-325. 334 Sylvia atricapiUa, 283 borin, 160 communis, 283 Synthliboramphus antiguurn, 290, 291 wumizusume, 290 Tachycineta thalassina. 315 t. lepida, 93 Takahe, 158 Tanager, Rufous-crowned, 228 Scarlet, 81 Western, 94 December 1970 Vol. 82, No. 4 INDEX TO VOLUME 82 485 Tungara cayana, 228 Tate, James, Jr., review by, 239; see Martin, Larry D., and Taxonomy, 70, 71, 93-94, 123-128, 204- 205, 355-369 Taylor, Walter Kingsley, The double- scratch in the genus Pooecetes, 465; Giant waterbug in an owl pellet, 462- 463 Taylor, Walter Kingsley, and Hugh Han- son, Observations on the breeding biology of the Vermilion Flycatcher in Arizona, 315-319 Teal, Blue-winged, 333, 334, 447 Green-winged, 461-462 Terborgh, John, and Jared Diamond, Niche overlap in feeding assemblages of New Guinea birds, 29-52 Tern, Arctic, 99, 383-390 Black, 435-444 Common, 99, 100, 464 Forster’s, 435-444 Roseate, 99 Ter res, John K., From Laurel Hill to Siler's Bog. The walking adventures of a naturalist, reviewed, 341-342; Songbirds in Vour Garden, reviewed, 240 Territory, 167-176, 177-183, 327-328, 446 Thamnophis sp., 95 sirtalis, 261 Thrasher, Brown, 74, 75, 77, 78, 80, 81, 330, 331, 375 Pearly-eyed, 464 Thrush, Gray-cheeked, 226 Hermit, 103, 226 Swainson’s, 226, 375, 379 Wood, 81 Timken, Richard L., Food habits and feed- ing behavior of the Baltimore Oriole in Costa Rica, 184-188 Tit, Blue, 271, 429 Great, 429, 4.30 Titmouse, Plain, 60 Tufted, 81, 177-183 Todiroslrum cinereiim jinitimum, 93 Tody-Flycatcher, Common, 93 Tolonen, Karl Eric, Ring-billed Gull and Laughing Gull catch fish by “plough- ing” and “skimming,” 222-223 Tulanus melanoleucus, 222 Towhee, Rufous-sided, 60, 77, 80, 81, 375, 379 T oxorhamphus i.liolophus, 31, 32, 33, 34, 35, 42, 49 Toxostoma curvirostre, 282, 285 rii-fum, 74, 81, 330, 375 Trichoglossiis haematodus, 31, 34, 35, 39, 44, 47, 49 Troglodytes aedon, 375 troglodytes, 282 T Urdus migratorms, 60, 81, 283, 375 Turkey, 465 Turnstone, Ruddy, 99 Twiest, Gilbert, see Holcomb, Larry C., and T yranniLS tyrannus, 374 verticalis, 93, 374 Tyto alba hellmayri, 101 Urocyon cinereoargenteus, 262 Vria sp., 18, 292 aalge, 289, 290 lomvia, 289 Van Wormer, Joe, The world of the Canada Goose, reviewed, 239 Veery, 226, 375, 379 V ermivora celata orestera, 93 luciae, 315 rujicapilla, 103 r. rujicapilla, 93 Vireo bellii, 283, 307 olivaceus, 81, 283, 375 solitarius, 81 Vireo, Bell’s, 307 Red-eyed, 80, 81, 375 Solitary, 81 Voice, 53-62, 83-91, 121—123, 167—176, 315- 316 Vole, Prairie, 262 Tundra, 133 Von Helversen, ()., see Bauer, W.. and Vulpes vulpes, 261 Vulture, Black, 462 Turkey, 44)2 Walcheck, Kenneth C., Nesting bird ecology of four plant communities in the Missouri River Breaks, Montana, 3/0— 382 Warbler, Audubon’s, 315, 355-369 486 THE WILSON BULLETIN December 1970 Vol. 82, No. 4 Blackburnian, 81, 400, 405, 416 Canada, 103 Chestnut-sided, 81 Garden, 160 Hermit, 464 Kentucky, 228 Kirtland’s, 76, 77 Lucy’s, 315 Myrtle, 355-369 Nashville, 93, 103 Orange-crowned, 93 Prairie, 281 Swainson's, 228 Willow, 160 Wilson’s, 94 Worm-eating, 228 Yellow, 174, 281, 375, 379 Waterthrush, Louisiana, 228 Northern, 93 Watson, John R., Dominance-subordination in caged groups of House Sparrows, 268-278 Wauer, Roland H., A second Swallow-tailed Kite record for Trans-Pecos Texas, 462 Waxwing, Cedar, 80, 81, 375, 465 Weasel, 261 Least, 134, 151 Weeks, Harmon P., Jr., Eastern Phoebe nesting in old Barn Swallow nest, 463- 464 Weeks, Sam E., review by, 112 Weights, 19, 123, 297, 299, 300, 425 Weisbrod, A. R., Food preferences of a hand-raised Blue Jay, 101-102 Weller, Milton W., Additional notes on the plumages of the Redhead iAythya americana) , 320-323; see Bergman, Robert D., and Widgeon, American, 464 Wilson Ornithological Society, Josselyn Van Tyne Memorial Liljrary, 103; Louis Agassiz Fuertes Award, 469; Mem- bership, 200; Officers, 474; Ornitho- logical News, 104, 229, 335, 467-469; Proceedings of the Annual Meeting, 343-352 Wilsonia canadensis, 103 pusilla pileolata, 94 p. pusilla, 94 Wolhuter, Bruce R., and Frank Kish, Courtship display observed between two species of huteos, 96-97 Wood, Merrill, A Bird-banders guide to determination of age and sex of se- lected species, reviewed, 339-341 Woodcock, American, 161, 327-328 European, 327, 328 Woodpecker, Downy, 374, 379 Imperial, 124 Ivory-billed, 124, 128 Linneated, 92 Magellanic, 115-129 Pileated, 463 Red-bellied, 463 Striped, 115 Woolfenden, Glen E., A putative skeletal specimen of the Flammulated Owl with Alabama locality data, 223-224 Wren, Cactus, 160 House, 375, 379 Rock, 375 Xanthocephalus xanthocephalus, 283 Xanthotis chrysotis, 31, 33, 34, 35, 42, 45, 46, 47, 48, 50 polygramma, 31, 32, 33, 34, 35, 42. 47, 48, 50 Yellowlegs, Greater, 22 Yellowthroat, 281, 375, 379, 464-465 Zenaidura macro lira, 96, 284, 374 Zohrer, James J., Observations on pre- migratory movements of hand-reared Mallards, 323-324; see Nellis, Carl M., and Zonotrichia alhicolHs, 102, 332 atricapilla, 332 leucophrys, 332 /. gambelii, 331-332 leucophrys X Z. albicollis, 331 Zosterops minor, 31, 34, 35, 43, 47, 49 This issue of The If i Ison Bulletin was published on 20 January 1971. Editor of The Wilson Bulletin GEORGE A. HALL Department of Chemistry West Virginia University Morgantown, West Virginia 26506 Editorial Advisory Board William C. Dilger Douglas A. James William A. Lunk Andrew J. Meyerriecks Helmut C. Mueller Robert W. Nero Kenneth C. Parkes Glen E. Woolfenden Ornithological Literature Editor Peter Stettenheim Box 79, Plainfield, New Hampshire 03781 Suggestions to Authors Manuscripts intended for publication in The Wilson Bulletin should be neatly type- written, double-spaced, and on one side only of good quality white paper. Tables should be typed on separate sheets. Before preparing these, carefully consider whether the material is best presented in tabular form. Where the value of quantitative data can be enhanced by use of appropriate statistical methods, these should be used. Follow the AOU Check-list (Fifth Edition, 1957) insofar as scientific names of United States and Canadian birds are concerned unless a satisfactory explanation is offered for doing otherwise. Use species names (binomials) unless specimens have actually been handled and subsequently identified. Summaries of major papers should be brief but quotable. Where fewer than five papers are cited, the citations may be included in the text. All citations in “General Notes” should be included in the text. Follow carefully the style used in this issue in listing the literature cited; otherwise, follow the “Style Manual for Biological Journals” (1964. AIBS). Photographs for illustrations should be sharp, have good contrast, and be on gloss paper. Submit prints unmounted and attach to each a brief but adequate legend. Do not write heavily on the backs of photographs. Diagrams and line drawings should be in black ink and their lettering large enough to permit reduction. Authors are requested to return proof promptly. Extensive alterations in copy after the type has been set must be charged to the author. Notice of Change of Address If your address changes, notify the Society immediately. Send your complete new address to the Treasurer, William A. Klamm, 2140 Lewis Drive, Lakewood, Ohio 44107. He will notify the printer. The permanent mailing address of the Wilson Ornithological Society is: c/o The MUSEUM of Zoology, The University of Michigan, Ann Arbor, Michigan 48104. Persons having business with any of the officers may address them at their various addresses given on the back of the front cover, and all matters pertaining to the Bulletin should be sent directly to the Editor. PLAN TO ATTEND THE 1971 ANNUAL MEETING The 1971 meeting of the Wilson Ornithological Society will be held jointly with the Alabama Ornithological Society on Dauphin Island, Alabama from Thursday, 22 April to Sunday, 25 April 1971. Transportation to the Island from the Mobile airport, 30 miles north, is being arranged by Mobile mem- bers of A.O.S. Chairman of the local committee for arrangements is Dr. M. Wilson Gaillard, 319 S. Sage Ave., Mobile, Ala. 36606. Detailed informa- tion concerning accommodations, transportation, and a call for papers will be sent to all members with advance registration forms. Accommodations include a Holiday Inn, registration headquarters (it will be warm enough to swim in the pool or the Gulf) and camping grounds with water and electricity. For efficiency apartments, ideal for families, write Mrs. Caroline Hager, an A.O.S. member, 130 Mississippi St., Dauphin Island, Ala. 36528. Rates are reasonable at this season. Dauphin Island is a narrow barrier sand island with 4 miles of pine inter- spersed with live oak and gum ponds and 10 miles of spartina salt marsh and beach. It is a resort, 30 miles due south of Mobile, built around a historic fishing village settled before Mobile or New Orleans. The Island is the first landfall for millions of trans-Gulf migrants from Central America. The period 20 April to 10 May is the peak when an active birder can record 80-120 species in one full day just on the island. The A.O.S. annual meeting held here every year by popular demand usually produces a bird list of over 170 species. The 6-year list (1964-69) contains 227 species. Those interesting species seen at least five times include Mag- nificent Frigatebird, Gannet, Cattle Egret, Am. Oystercatcher, Wilson’s Plover, Gull-billed Tern, Royal Tern, Sandwich Tern, Chuck-will’s-widow, Gray King- bird (nests), 19 species of warblers. Blue Grosbeak, and Painted Bunting. Seen at least once are Red-throated Loon, Brown Booby, Glossy Ibis, Mottled Duck (nests). Surf Scoter, Mississippi Kite, Purple Gallinule (3), Snowy Plover, Long-billed Curlew, Black-necked Stilt, Ground Dove (3), Swainson’s Warbler, Lawrence’s Warbler, Audubon’s Warbler, Lark Sparrow. Other in- teresting species seen in late April on the Island include Eared Grebe, Reddish Egret, Swallow-tailed Kite, Western Kingbird, Bell’s Vireo, Black-whiskered Vireo, Black-throated Gray Warbler, and Western Tanager. IMPORTANT NOTICE FOR SUBSCRIBERS TO THE WILSON BULLETIN The annual subscription price (for non-members and institutional subscribers) has been increased from $6 to $10. This increase takes effect for all subscriptions to Volume 83, 1971. Mua COMP, zoou LIBRAPY -lU THE FEB 91971 HARVARD UNiVKRSfTY. WILSON ORNITHOLOGICAL SOCIETY MEMBERSHIP LIST • 1970 Supplement to THE WILSON BULLETIN (Vol. 82, No. 4, December, 1970 JO S SMCO |\pr» fin Q^♦AV>^AH The Wilson Ornithological Society MEMBERSHIP LIST 1970 Supplement to the December 1970 Wilson Bulletin Pat rons Baggj Aaron Moore, Farm St., Dover, Mass. 02023 1948 Batts, H(enry) Lewis, Jr., 2315 Angling Rd., Kalamazoon, Mich. 49001 1946 Booth, Mrs. Robert V. 0., 1085 Bank St., Painesville, Ohio 44077 1949 Brecher, Leonard C(harles), 1900 Spring Drive, Louisville, Ky. 40205 1939 Carnes, Mrs. Herbert E. , 11801 Sundown Ave. , Scottsdale, Ariz. 85251 1944 Chalif, Edward Louis, 15 Sterling St., W. Newton, Mass. 02165 1947 Desmond, Thomas C(harles), Box 670, Newburgh, N.Y. 12553 1942 Emerson, Guy Deceased Foster, John H(awley), P. 0. Box 204, Wayne, Pa. 19087 1952 Furman, Dr. Robert H(oward), Clinical Research, Eli Lilly 5- Co., 307 East McCarty Ave., Indianapolis, Ind. 46206 1955 Goelet, Robert G. , 425 Park Ave., New York, N.Y. 10022 1953 Hamilton, Charles W(hlteley), 2639 Fenwood Rd. , Houston, Texas 77005 1948 Klamm, William A(lclen), 2140 Lewis Dr., Lakewood, Ohio 44107 1957 Lory, Mrs. Hazel Bradley, Rt. 2, Box 41, Momence, 111. 60954 1944 Mills, Herbert H. , Arrowhead Farms, Rt. 3j Bridgeton, N.J. 08302 1951 Peterson, Roger Tory, Neck Rd. , Old Lyme, Conn. 06371 1942 Root, Oscar M(ltchell) Deceased Spelrs, Mrs. Doris Huestls, 1815 Altona Road, Pickering, Ont., Canada 1936 Spofford, Walter R(lchardson) II, 568 Main St., Etna, N.Y. 13062 _ ^ 1942 Stettenhelm, Peter, Box 13, Westgate Rd., Plainfield, N.H. 03781 1951 Stokes, Allen W. , Dept, of Wildlife Management, U. S. A. C. , Logan, Utah 84321 Stoner, Lillian C., 399 State St., Albany, N.Y. 12210 Street, Phillips B(orden), Rt. 1, Chester Springs, Pa. 19425 Sutton, George Mlksch, Dept, of Zoology, Unlv. of Oklahoma, Norman, Okla 73069 '920 Strong, Reuben M. ^ Founder, Deceased Swetland, David W. , Daisy Hill, Chagrin Falls, Ohio 44022 Tucker, Mrs. Carll, Penwood, Mt. Kisco, N.Y. 10549 Van Tyne, Josselyn Wlckstrom, George M(artln), 2293 Harding Ave., Muskegon, Mich. 49441 1950 1945 1946 1953 1928 Deceased 1951 ’’fLife Member ^^Susta i ni ng Member Others - Active Members Abbott, Waldo G. , Museum of Natural History, Santa Barbara, Calif. 93105 1963 Able, Kenneth P(aul), Dept, of Zoology, Univ. of Georgia, Athens, Ga. 30601 1965 Abraitys, Vincent, Sergeantsvi 1 1 e. New Jersey 08557 1956 Abrell, R(obert) Joseph, 3137 Ronald Ct., Spring Valley, Calif. 92077 1969 Acton, James Frederick, 3327 West 4th Ave. , Spokane, Wash. 99204 1967 Adams, C(lyde) Bruce, Route 1, Cranbury Road, Cranbury, N. J. 08512 1959 * Adams, Herman P(urdy), 7 Highland Ave., Maplewood, N.J. 07040 1959 Adams, Raymond J. , Jr., 3378 Oakdale Drive, Hickory Corrors, Mich. 49060 1969 Adams, William Hensley, Jr., 4004 Moss Drive, Annandale, Va. 22003 1951 **Adelson, Richard Henry, Remsen's Lane, Rt. 1, Oyster Bay, L. I . , N.Y. 11771 1938 Adkisson, Curtis S(amuel), Museum of Zoology, Univ. of Mich., Ann Arbor, Mich. 48104 1963 Agey, Ho Norton, 908 Avenue H, N. E. , Winter Haven, Fla. 33880 I960 Ahlquist, Jon Edward, Peabody Museum of Natural History, Yale Univ., New Haven, Conn. 06520 1959 Ainley, David G(eogre), 608 Pathob io 1 ogy, Johns Hopkins Sch. Hygiene & Pub. Hlth., 615 No. Wolfe St., Baltimore, Md. 21205 1969 **Aldrich, John Warren, 6324 Lakeview Dr., Falls Church, Va. 22041 1930 **Alexander, Donald C(hild), Batchelder's Landing, Rowley, Mass. OI969 1937 ■**A 1 exander, Gordon, 765 14th St., Boulder, Colo. 80302 1936 '**Allen, Charles D(avid), Montgomery Rd. , Rocky Hill, N.J. 08553 1969 Allen, Thomas Moore, 47 Middlesex Rd. , Darien, Conn. 06820 1970 Allez, George (Nicholas), 309 North Hillside Terrace, Madison, Wis. 53705 1969 Allyn, (Paul) Richard, 709 Myers Bldg., Springfield, 111. 62701 1944 Almon, Lois, 4909 South Auburn Drive, Mobile, Ala. 36618 1958 * Altemus, Edward Lee, Lafayette Ave., Fort Washington, Pa. 19034 1954 Altsheler, Mrs. Yancey R(oberts), 8OO S. 4th St., Apt. 2606, Louisville, Ky. 40203 1954 Amadon, Dean, American Museum of Natural History, Central Park West at 79th St., New York, N.Y. 10024 1935 Amason, Carl R(aymond), Rt. 3, Box I80, El Dorado, Ark. 71730 1968 * Ames, Peter L. , 2713 Walnut Ave., Evanston, 111. 60201 1963 Anaka, William, Box 62, Gorlitz, Saskatchewan, Canada 1957 Andersen, Elmer L(ee), 2230 W. Hoyt Ave., St. Paul, Minn. 55108 I965 Anderson, Anders H(arold), 3221 East Kleindale Rd. , Tucson, Ariz. 85716 I937 2a Anderson, Bertin W(alter), Biology Dept., Northwestern State College, Alva, Okla. 73717 I966 Anderson, Donald L. , Dept, of Biology (Leidy Hall), Univ. of Penna., Philadelphia, Pa. 19104 I965 Anderson, Eugene N(ewton), Jr., Anthropology Dept., Univ. of Calif., Riverside, Riverside, Calif. 92502 1964 Anderson, H(arrison) Cook, 289 Pleasant St., Laconia, N. H. 03246 ]S68 Anderson, John M. , West Cornwall Rd. , Sharon, Conn. 06069 1938 Anderson, Mrs. Paul T. , Wolf Trap Hill, Rt. 2, Winter St., Mi dd 1 eborough. Mass. 02346 I96I Anderson, Richard A(rlen), 1147 Greenshaw Drive, St. Louis, Mo. 63137 1963 Anderson, R. K. , Dept, of Nat. Resources, Wisconsin State Univ., Stevens Point, Wise. 54481 I962 Anderson, Ted R(oger), 9553 Plainfield Dr., Rock Hill, Mo. 63119 1964 Anderson, Mrs. Vivian Telford, Dept, of Zoology, Utah State Univ., Logan, Utah 84321 1970 Anderson, William L(eno), 279 Natural Resources Bldg., Urbana, 111. 6I8OI 1965 Andrle, Robert F. , Buffalo Museum of Science, Humboldt Park, Buffalo, N.Y. 14211 I966 Anthes, Clarence A(1vin), 707 North Moreland Blvd., Waukesha, Wise. 53186 1939 Anthony, Larry W. , Pueblo Height Mobile Park, No. 30, Globe, Ariz. 85501 1970 Arbib, Robert S(imeon), Jr., 226 Guion Dr., Mamaroneck, N.Y. 10543 1947 * Armistead, Henry T., 39 Benezet St., Philadelphia, Pa. 19118 1966 Arner, Dale H., Dept, of Wildlife Management-Drawer LW, Mississippi State Univ., State College, Miss. 39762 1964 * Arnold, Elting, 4914 Dorset Ave., Chevy Chase, Md. 20015 1941 Arnold, Keith A(lan), Dept, of Wildlife Sciences, Texas A. S- M. Univ., College Station, Texas 77843 I960 Arny, Samuel A., 76O8 Hamlet St., Springfield, Va. 22151 1947 Atkeson, Thomas Z(ephaniah), P. 0. Box 1643, Decatur, Ala. 35601 ^ 1953 Austin, Mrs. Dorothy Allen, P. 0. Box 127, Tumacacori, Ariz. 85640 1967 Austin, George T(rout), 1147 E. Adelaide Dr., Tucson, Ariz. 85719 1966 Austin, Mrs. Harold C. , 1116 Mandana Rd., Oakland, Calif. 94610 1950 Austin, Oliver L(uther), Jr., Florida State Museum, Gainesville, Fla. 32601 1930 **Avent, Carrie Pillow, Minter City, Miss. 38944 1959 Axtell, Harold H. , Buffalo Museum of Science, Humboldt Park, Buffalo, N.Y. 14211 1950 Baepler, Donald H(enry), Nevada Southern Univ., Las Vegas, Nev. 89 109 1955 Bailey, Alfred Marshall, Denver Museum of Natural History, City Park, Denver, Colo. 80206 1928 Bailey, Mrs. Harold H(arris), Rockbridge Alum Springs Biological Laboratory, Rt. 2, Goshen, Va. 24439 1963 3a Bai leyj W. Wallace, Director, Wellfleet Bay Wildlife Sanctuary, Box 236, South Wellfleet, Mass. 02663 1959 **Baird, James, 69 Hartwell Ave. , Littleton, Mass. 01460 1954 Baird, Mrs. Thomas C. , 1200 Cobb Blvd., Kankakee, 111. 60901 _ 1968 *Baker, Bernard W. , Rt. 1, Judson Road, Spring Lake, Mich. 49456 1938 Baker, Paul S(eaman), 113 Copse Way, Williamsburg, Va. 23185 , 1946 Baker, Roll in Harold, The Museum, Michigan State Univ., East Lansing, Mich. 48823 1938 Baker, William C(alvin), 559 Euclid St., Salem, Oh I o 44460 1 93 1 Balch, Lawrence G. , 6209 N. Sacramento Ave., Chicago, 111. 6o645 1970 Baida, Russell P(aul), 3827 N. Paradise Rd., Flagstaff, Ariz. 86OOI 1967 Baldwin, Paul H. , Dept, of Zoology, Colorado State Univ., Fort Collins, Colo. 80521 1956 Balgooyen, Thomas G. , Univ. of California at Berkeley, 2593 Life Science Bldg., (MVZ), Berkeley, Calif. 94720 1968 Ball, Kathleen E. , 11719 133rd St., Edmonton, Alberta, Canada 1946 Ball, Robert E(dwin), 1 689 Meadow Lane Dr., S. E. , North Canton, Ohio 44709 1968 Ball, W(illiam) Howard, 4322 Sheridan St., University Park, Hyattsville, Md. 20782 I96I Balsom, Mrs. Amos Parker, 2209 £• Stratford Court, Milwaukee, Wise. 53211 1949 Bancroft, Griffing, Captiva island, Fla. 33924 1968 Banks, Clinton S(eeger), 202 Wilma Ave., Steuben- vi lie, Ohio 43952 1945 * Banks, Richard C(harles), Bird & Mammal Labs., U. S. National Museum, Washington, D. C. 20560 1959 Banta, Edna, Rt. 1, Nashville, Ind. 47448 1945 Barbour, Llewellyn P(helps), 4780 Wood St., Willoughby, Ohio 44094 1948 Barlow, Jon Charles, Dept, of Ornithology, Royal Ontario Museum, 100 Queen's Park, Toronto 5, 1959 Toronto 5j Ontario, Canada Barre, Vitus S(ebastian), Jr., 4601 Woodlawn, Little Rock, Ark. 72205 I969 Barrett, Paul W. , Supreme Court Bldg., Jefferson City, Mo. 65101 1967 Barrett, Ronald W. , Wisconsin State Univ., Ford du Lac Campus, Fond du Lac, Wise. 54935 I968 Barry, Jerome J. , 119 Shore Drive, Nashua, N. H. 03060 I967 * Bartel, Karl E(mil) Edgar, 2528 West Collins St., Blue Island, 111. 60406 I934 Bartlett, Guy, 1053 Parkwood Blvd., Schenectady, N.Y. 12308 1938 * Bartlett, L(awrence) M(atthews), 83 Spring St., Amherst, Mass. 01002 I957 Bastin, Eric W(alter), 175 Catherine St., S. , Apt. 55, Hamilton, Ont., Canada I95I Batchelder, Edgar M(arden), 56 Orchard St., Marble- head, Mass. 01947 1941 Bauer, Kurt M(ax), Natural History Museum, P. 0. Box 417j a 1014 Vienna, Austria I966 4a * Baunij William W.j 1257 Cranford Ave.j Lakewood, Ohio 44107 1963 Baylor, L(eslie) M(ilton), Dept, of Languages, South Dakota School of Mines, Rapid City, S. D. 57701 1954 Baysinger, Earl BCaVton), 67OI Carlinda Ave. , Ellicott City, Md. 21043 1970 Beason, Robert Curtis, Box 223, Valley Center, Kans. 67147 1968 * Beckett, T. A., Ill, Magnolia Gardens, Rt. 4, Charleston, S. C. 29407 1963 Beckley, Mrs. F. S. , Box 805, Bancroft, Ontario, Canada 1969 Beddall, Mrs. Barbara G(ould), 2502 Bronson Rd. , Fairfield, Conn. 06430 1958 Beecher, William J(ohn), Chicago Academy of Sciences, 2001 Clark St., Chicago, III, 606l4 1948 Beer, James R(obert), Dept, of Entomology, Fishery 8- Wildlife, Univ. of Minnesota, St. Paul, Minn. 55101 1957 * Behle, William H(arroun), Dept, of Biology, Univ. of Utah, Salt Lake City, Utah 84110 1935 Behrens, Harry Carl, Box 1055^ Rapid City, S. D. 57702 1950 * Belcher, Paul Eugene, 21 Hampshire Rd. , Akron, Ohio 44313 1938 * Belkna, John B(alcom), 92 Clinton St., Gouverneur, N. Y. 13642 1959 Bell, Henry 111, U. S. Geological Survey Bldg., Agricultural Research Center, Beltsville, Md. 20705 1946 Bell, Joseph L. , Bronz Zoo, I85th St. and South Blvd., Bronx, N.Y. 10460 1967 Bell, Miriam, 2257 Upton Ave., Apt. 11, Toledo, Ohio 43606 1958 Bell, Ralph K(ennedy), Rt. 1, Box 229^ Clarksville, Penna. 15322 I963 Bellrose, Frank G. , Jr., Illinois Natural History Survey, Havana, 111. 62644 1963 ^■^Belton, William, c/o American Consulate, Porto Alegre, A. P. 0. New York, N.Y. 09676 1970 Bender, Charles R(ichard), 364 Alex Hamilton, San Antonio, Texas 78228 i960 Bennett, Esther V(orena), 600 S. 33rd St., Lincoln, Neb. 68510 1954 Benton, Allen H(aydon), Dept, of Biology, State College, Fredonia, N.Y. 14063 1953 * Berger, Andrew J(ohn), Dept, of Zoology, Univ. of Hawaii, Honolulu, Hawaii 96822 1940 * Berger, Daniel D(avid), 510 E. MacArthur Rd. , Milwaukee, Wise. 53217 1953 * Bergstrom, E(dward) Alexander, 37 Old Brook Rd. , West Hartford, Conn. 06107 1943 Berrett, Delwyn Green, 55“466 loseppa St., Laie, Oahu, Hawaii 96762 1959 Betts, Amelia J(eannette), Baldwin Cith, Kan. 66OO6 1953 Biaggi, Virgilio, Jr., College of Agriculture, Mayaguez, Puerto Rico, West Indies OO708 1945 * Bibbee, P. C. , Dept. of’Biology, Davis £• Elkins College, Elkins, W. Va. 262^1 1958 * Biddle, E. Turner, Leiters Ford, Ind. 46945 I96O Bierly, Michael L(ee), 3826 Bedford Ave., Nashville, Tenn. 37215 1966 5a Biqqer, Walter K. , Star Rt. , Trout Run^ Penna. 17771 1963 Billeb, Stephen L. , Dept, of Animal & Range Sciences Montana State Univ. , Bozeman, Mont. 59715 1962 Binford, Laurence C(harles)j California Academy of Sciences, Golden Gate Park, San Francisco, Calif. 94118 ^ ^ ^ 1954 Birch, Robert Lee, Dept, of Biology, West Virginia Univ. , Morgantown, W. Va. 2650b 1950 Bircher, J(ames) A(lbert), 860 Field Club Rd. , Pittsburgh, Pa. 15238 _ 1968 Birkenstein, Mrs. Lillian, Tenerias 33, San Miguel Allende, Gto. , Mexico 1967 Bishop, Earl, Dept, of Botany, Univ. of Hawaii, 2450 Campus Rd., Honolulu, Hawaii 96822 1962 Black, Charles T(heodore), 4714 N. Van Atta Rd., Okemus, Mich. 48864 1935 Black, Gladys B. , 608 De Witt, P 1 easantvi 1 1 e, Iowa 50225 1963 Blacklock, Gene W. , 3458 Southland, Corpus Christ!, Texas 78408 1970 Blades, Herbert, Rt. 2, Box 410, Hockessin, Del. 19707 1962 Blake, Charles H(enry), P. 0. Box 613, Hillsboro, N. C. 27278 1950 Blake, Emmet R. , Chicago Natural History Museum, Roosevelt Rd. & Lake Shore Dr., Chicago, 111.60605 1939 Blakeslee, Howard E. , 1722 East 45th St., Ashtabula, Ohio 44004 1959 Blakeslee, William P. , 38 Montclair Ave. , Rosl indale. Mass. 02131 1965 *Bleitz, Donald Lewis, 5334 Hollywood Blvd. , Los Angeles, Calif. 90027 1948 Blitcharz, Raymond J. , 827 Pennsylvania Avenue, Trenton, N. J. 08638 1967 Blount, Elizabeth R(ose), 741 Ruiz St., San Antonio, Texas 78207 1961 *Bock, Walter (Joseph), Columbia University, New York, N.Y. 10027 1953 Bodsworth, Fred, 294 Beech Ave., Toronto 13, Ont., Canada 1956 Bolen, Eric G(eorge), Texas Tech Univ., Range & Wildlife Mgmt., Lubbock, Texas 79409 1964 Boles, Walter E. , 2007 Briarcliff Lane, Emporia, Kan. 66801 1970 Bomm, Mrs. J. Henry, 674 Pascack Rd. , Washington Twp., P. 0. Westwood, N. J. 07675 1965 * Bond, James, 1900 Race St., Philadelphia, Pa. 19103 1945 Bond, Richard M(arshall), Kingshill, P. 0. Box 166, St. Croix, U. S. Virgin Islands 00850 1936 Boone, George C. , Dept, of Biology, West Virginia Univ., Morgantown, W. Va. 26506 I96I Booth, Mrs. Robert P. , Shirley Hill Rd. , Rt. 2, Manchester, N. H. 03102 I968 Bordley, James MI, 13 Main St., Cooperation, N.Y. 13326 1957 Bordner, Dorothy L. , 926 West Beaver Ave., State College, Pa. 1 68O 1 I959 * Borror, Donald J(oyce), Dept, of Zoology S- Entomology, Ohio State Univ., Columbus, Ohio 43210 1927 Bouchard, Marc G(ilbert), 102 Lock St., Nashua, N. H. 03060 1970 6a * Boulton, Rudyerd, Box 8305 Causeway, Salisbury, South Rhodesia Bourdo, Eric Albert, Jr., Ford Forestry Center, L'Anse, Mich. 49946 Bourget, Andre, Canadian Wildlife Service, 2700 Blvd. Laurier, Suite 801, Ste-Foy, P. Q. Canada **Bowers, Norman W( i 1 1 i am). Box 45 9, Lennoxville, Que. , Canada Bowman, Robert L, Dept, of Biology, San Francisco State College, 1600 Holloway Ave., San Francisco, Calif. 94132 Boyd, Elizabeth M(argaret), Mount Holyoke College, South Hadley, Mass. 01075 Boyd, Ivan L. , Dept, of Biology, Baker Univ. , Baldwin City, Kan. 66006 Boyd, Roger L(ee), 1020 7th, Baldwin City, Kan. 66006 Brackbill, Hervey G(roff), 2620 Poplar Dr., Baltimore, Md. 21207 ■^^B rad burn, Donald Muir, 465 Audubon St., New Orleans, La. 70118 Brady, Alan, Box 103, Wycombe, Pa. I896O Branch, Mrs. Margaret G(amble), 711 N. Halifax Ave., Daytona Beach, Fla. 32018 Branum, Florence (Pauline), 727 Rutter Ave., Lancaster, Ohio 43130 * Braun, Clait E. , Colorado Div. of Game, Fish & Parks, P. 0. Box 567, Fort Collins, Colo. 80521 Brauner, Joseph, 10426 Baird Ave., Northridge, Calif. 91324 * Breckenr idge, Walter J(ohn), Museum of Natural History, Univ. of Minnesota, Minneapolis, Minn. 55414 Breitweiser, Mrs. Alberta P(auline), 1002 Chestnut St., Anderson, Ind. 46102 Brenner, Frederick J(ames), Grove City College, Grove City, P. 16127 Brewer, Richard Dean, Dept, of Biology, Western Michigan Univ., Kalamazoo, Mich. 4-9007 * Briant, Alice M(ary), I90 Pleasant Grove Rd. , Apt. 1-4, Ithaca, N. Y. 14850 Briggs, Shirley A(nn), 7605 Honeywell Lane, Bethesda, Md. 20014 Brigham, Edward M(orris) III, Rt. 4, Red Wing, Minn. 55066 Brigham, Edward M(orris), Jr., Rt. 9} Box 145j Battle Creek, Mich. 49017 Broadbooks, Harold E(ugene), Southern Illinois Univ., Edwardsvi 1 1 e. Ml. 62025 Brock, J(ean) A(udrey) M(ae), 9752 Old Warson Rd. , St. Louis, Mo. 63124 * Brodkorb, Pierce, Dept, of Biology, Univ. of Florida, Gainesville, Fla. 32603 Brooke, Mrs. Margaret, 126 51st St., Des Moines, 1 owa 50312 * Brooks, Maurice Graham, Div. of Forestry, Morgantown, W. Va. 26506 Brooks, Wi 1 1 iam S(tewart), Dept, of Biology, Ripon, Wise. 54971 , ^ , Bross, Alfred F(rancis), 70 Round Meadow Lane, Hatboro, Penna. 19040 1957 1951 1969 1970 1962 1941 1951 1970 1942 1950 1959 1952 1946 1966 1942 1929 1964 1965 1949 1968 1965 1960 1931 1948 1967 1951 1958 1927 1966 1970 7a Broun, Maurice, Rt. 1, New Ringgold, Pa. 179^0 Brown, Jerram L. , Biology Dept., Univ. of Rochester, N. Y. 14627, Rochester, N.Y. * Brown, Lawrence A(llyn), Jr., 434 Marlboro St., Boston, Mass. 02115 Brown, N(orman) Rae, 100 Burpee St., Nashwaaksis, N. B. , Canada Brown, Richard D. , 332 E. Clearview St., Worthington Ohio 43085 Brown, R(ichard) G(eorge) B(olney), Canadian Wildlife Service, Post Office Bldg, Aurora, Ont., Canada Brown, Woodward H(art), 4815 Ingersoll Ave. , Des Moines, Iowa 50312 Browne, Micou M(etcalf), 2728 Cambridge Rd. , Raleigh, N. C. 27608 Browning, M(arvin) Ralph, 4121 N. 4th St., Apt. 4, Arlington, Va. 22203 Brownstein, Richard, 85 Garden Court, Amherst, N.Y. 14226 Bruce, James A(ddison), Whitehall Square Apts., Apt. 102, 4144 Suitland Rd. , Suitland, Md. 20023 Bruning, Donald F. , New York Zoological Park, 185th & Southern Blvd., Bronx, N.Y. 10460 Bryan, Burton Donald, Box 2, Adamsville, R. I. 02801 **Bryens, Oscar McKinley, Rt. 1, White Pigeon, Mich. 49099 Buchheister, Carl W. , 7814 Marion Lane, Bethesda, Md. 20014 Buckley, P(aul) A(nthony), Dept, of Biology, Hofstra Univ., Hampstead, L. I . , N.Y. 11550 * Bucknell, Donald N(eedham), 134 Wonham, Ingersoll, Ont., Canada Bull, John, Dept, of Ornithology, American Museum of Natural History, Central Park West at 79th St., New York, N.Y. 10024 Bulmer, Walter, 2327 Duke St., Apt. C-2, Alexandria, Va. 22314 Burger, Joanna, Museum of Natural History, Univ. of Minnesota, Minneapolis, Minn. 55455 Burk, Myrle M. , Rt. 2, Waterloo, Iowa 50701 Burnham, Gladys L(ou), Howard County Junior College, Big Spring, Texas 79720 * Burns, James Henry, 800 Lowerline St., New Orleans, La. 70118 Burns, Robert David, Dept, of Biology, Kenyon College, Gambler, Ohio 43022 Burr, Irving W(ingate), 1141 Glenway, West Lafayette, Ind. 47906 **Burrell, Helen E. , 1523 Orchard Drive, Kalamazoo, Mich. 49002 Burt, DeVere Eugene, The Nature Conservancy, 260 Ludlow Ave., Cincinnati, Ohio 45220 Burtt, Benjamin P. , 61 61 Smokey Hollow Rd., James- ville, N.Y. 13078 Burtt, Edward H. , Jr., Dept, of Zoology, Birge Hall, Univ. of Wisconsin, Madison, Wis. 53706 Burtt, Harold E. , 2163 N. Starr Ave., Columbus, Ohio 43221 Bushman, John, U. S. Army Material Command, Bldg. 100, Ft. Douglas, Utah 84113 1935 1950 1958 1945 1967 1968 1949 1 966 1967 1966 1952 1968 1949 1924 1943 1 966 1953 1952 1970 1962 i960 1954 1942 1948 1945 1962 1970 1956 1970 1953 1951 8a Buskirk, William H(ugh), Dept, of Zoology, Univ. of California, Davis, Davis, Calif. 956I6 I967 Butler, Edward Murrell, 720 S. Jefferson, Port A1 1 en. La 70767 1970 Byrd, Mitchell A(gee), Dept, of Biology, College of William and Mary, Williamsburg, Va. 23185 I965 Caccamise, Donald F(rancis), Dept, of Biology, Box 3AF, New Mexico State Univ., Las Cruces, N. M. 88001 Cadbury, Joseph M. , I08 W. Phi 1-El lena St., Philadelphia, Pa. 19119 Cade, Tom J. , Laboratory of Ornithology, Cornell Univ., Ithaca, N.Y. 14850 Cahalane, Victor H(arrlson), Derbyshire Rd. , Clarksville, N.Y. 12041 Cain, Brian W. , 2410 E. Main Lot 11, Urbana, III.6I8OI * Caldwell, Larry D. , Box 427j Central Michigan Univ., Mt. Pleasant, Mich. 48858 Caldwell, Patrick J(ohn), 305 Rolfs Hall, School of Forestry, Univ. of Florida, Gainesville, Fla. 32601 Callison, Charles H. , National Audubon Society, 1130 Fifth Ave., New York, N.Y. 10028 Calvert, Earl Wellington, Rt. 2, County Home, Lindsay, Ont. , Canada Calvin, Robert L(eal), Rt. 3^ Randall Dr., New Castle, Penna. 16101 Campbell, Kenneth (Eugene), Jr., Dept, of Zoology, Univ. of Florida, Gainesville, Fla. 32601 Campbell, Louis W(alter), 4531 Walker Ave., Toledo, Ohio 43612 Campbell, Mildred F(lorence), 29 North Hawthorne Lane, Indianapolis, 1 nd. 46219 Carleton, Geoffrey, Box 5641, Daytona Beach, Fla. 32020 Carpenter, Charles C. , Depto of Zoology, Room 222, 730 Van Vleet Oval, Univ. of Oklahoma, Norman, Okla. 73069 Carpenter, Floyd S. , 2402 Longest Ave. , Lou i svi 1 1 e, Ky. 40204 *Carrick, W(illiam) H(enesey), Niska Waterfowl Research Centre, 387 Kortright Rd. , Rt. 6, Guelph, Ont. Canada *Carrothers, Vera, I89O E. 107th St., Cleveland, Ohio 44106 Carter, Mrs. B. Clyde, 148 Saluda St., Chester, S. C. 29706 Carter, Dennis L(ee), Crater of the Moon National Monument, Arco, Idaho 83213 **Carter, Mrs. E. W. , Ohio Rt. 2, Perrysburg, Ohio 43551 Carter, J(ay) H. , 111, P. 0. Box 89lj Southern Pines, N. C. 28387 ■^Carter, William A., Rt. 4, Ada, Okla. 74820 Case, Ronald M. , Div. of Biology, Kansas State Univ., Manhattan, Kan. 66502 Casemore, Lulu M(yrtle), 8111 Mendota Ave., Detroit, Mich. 48204 Cassel, J(oseph) Frank(lin), Dept, of Zoology, North Dakota State Univ., Fargo, N. D. 58103 Casto, Stanley D(ale), Dept, of Biology, Texas Tech. College, Lubbock, Texas 79409 1970 1963 1950 1933 1966 1964 1969 i960 1937 1951 1970 1926 1938 1967 1951 1934 1960 1938 1968 1947 1946 1966 1961 1970 1968 1940 1969 9a **Caswell, Herbert Kfall), 952 Sheridan St., Ypsilanti, Mich. 48197 ’959 Chamberlain, Dwight R. , 4004 48th St., Bladensburg, Md. 20710 ^ . 19o5 Chambers, Glenn D. , 1703 Highridge Drive, Columbia, Mo. 65201 1959 Chandler, Reg(inald) E(dmund), 19 Huron Heights Dr., Apt. 2, Newmarket, Ont. , Canada ^ 19^7 Chapman, Brian R(ichard), Texas Tech Univ., Dept. of Biology, P. 0. Box 4149, Lubbock, Texas 79409 1970 Chapman, Joseph A,, Univ. of Maryland, Natural Re- sources Institute, Box 3266, LaVale, Md. 21502 1967 Chapman, Mrs. Wayne, Rt. 2, Ducktrap, L i ncol nvi 1 1 e, Maine 04849 19^9 Chase, Charles Greenough, Rt. 3, Wiscasset, Maine 04578 1959 Chase, Theodore, Jr., Dept, of Biochemistry & Micro- biology, College of Agriculture, Rutgers - The State University, New Brunswick, N. J. O8903 i960 Chernesky, Steven, Institute of Animal Behavior, 101 Warren St., Newark, N. J. 07102 I968 Choate, Ernest A., Cape May Point, N. J. 08212 1954 Christencon, Carter D(rew), Dazey, N. Dak. 54829 1970 Christie, David S. , 13 Spruce St., Saint John, N. B. , Canada 1962 Christy, James Edward, 9226 Phillips Ave. , Chicago, 111. 60617 1966 Church, Mrs. Herbert M. , Jr., 2335 N. Edgewood St., Arlington, Va. 22201 1963 Cink, Calvin L. , Dept, of Zoology, Univ. of Nebraska, Lincoln, Neb. 68508 1967 Clapp, Roger B, , Research Curator, Pacific Program, Smithsonian Institution, Washington, D. C. 20560 I966 * Clark, George A(lfred), Jr., Biological Sciences Group, Univ. of Connecticut, Storrs, Conn. 06268 1955 Clark, George C(lifford), Toivo St., Rt. 12, Thunder Bay, Ont., Canada I96I Clark, Richard James, Laboratory of Ornithology, Cornell Univ., Ithaca, N. Y. 14850 1969 Clark, Robert A., Lewis St., Petersham, Mass. 01366 1964 Clark, William S. , 5751 Sanger Ave., Apt. 231, Alexandria, Va. 22311 1969 Clarke, William S(loan), Jr., 516 E. College Ave., State College, Pa. I68OI I966 * Clarkson, Mrs. Edwin 0., Wing Haven, 248 Ridgewood Ave., Charlotte, N. C. 28207 1940 Clement, Roland C(harles), Weed Ave., R. F. D. , Norwalk, Conn. 06850 1941 * Clements, H(iram) Everest, 35 Argyle St., Rochester, N.Y. 14607 1949 **Clench, Mary He imerd i nger. Section of Birds, Carnegie Museum, Pittsburgh, Pa. 15213 1955 Closas, Ramon Espinasa, Apartado Postal 53 IO6, Mexico (17) D. F., Mexico 1969 * Clow, Marion, Box I63, Lake Forest, 111.60045 1929 Clyde, E(dward) C(alvin), Jr., Box 495, Effingham, S. C. 29541 1963 * Coffey, Ben Barry, Jr., 672 Belvedere, Memphis, Tenn. 38107 1927 Coffey, Lula C(ooper), 672 North Belvedere, Memphis, Tenn. 38107 1952 Cogswell, Howard L(yman), Dept, of Biological Science, Cal ifornia State Col lege at Hayward, Hayward, Calif. 94542 ■^^Cohn, Mrs. Jean W. , 4787 Beaumont Drive, La Mesa. Calif. 92041 * Cole, Mrs. Richard D. , 625 Valley Lane, Towson, Md. 21204 Collier, Gerald, Dept, of Zoology, San Diego State College, Sab Diego, Calif. 92115 * Collins, Charles T(hompson), Dept, of Biology, California State College at Long Beach, Long Beach, Calif. 9080 1 Colton, Harold S(ellers), Box 699, Flagstaff, Ariz. 86001 Comer, C ( ha r 1 es W( i 1 1 i am) , 815 W. 9th Ave. , Emporia, Kan. 66801 Compton, Mrs. L. E. , 2745 So. Genessee Rd. , Waukesha, Wise. 53186 * Compton, Lawrence V(erlyn), Biology Division, Soil Conservation Service, Washington, D. C. 20250 * Conboy, Mrs. John W. , 417 Studebaker St., Mishawaka, Ind. 46544 Condee, Ralph W. , 443 East Waring Ave., State Col 1 ege. Pa. 1 68O 1 Conn, Robert Car land, 755 Ross Lane, Bound Brook, N. J. 08805 Conrad, Charles L(ouis), Rt. 1, Triadelphia, W. Va. 26059 Conway, C(harles) Abbott, Rt. 1, Puslinch, Ont. , Canada Conway, Mrs. Isabella Anderson, Rt. 1, Puslinch, Ont. , Canada **Conway, William G. , New York Zoological Park, l85th St. and Southern Blvd., New York, N. Y. 1 0460 Coon, Donald W(ayne), 300 Highland, College Station, Texas 77840 Cooper, Donald M. , Dept, of Biology, The City College of The City University of New York, New York, N.Y. 10031 Cooper, Murray Michael, Dept, of Biology, Western Michigan Univ., Kalamazoo, Mich. 49001 Cope, James B(onwi 1 1 ), Earlham College, Richmond, Ind. 47374 Cornwell, George W(illiam), Forestry Dept., 305 Rolfs Hall, Univ. of Florida, Gainesville, Fla. 32601 ^"^Cors, Paul B(eaumont), 1409 Garfield St., Laramie, Wyoming 82070 Costello, C(harles) Michael, 717 Shawnee Ave., Cumber- land, Md. 21502 **Cottam, Clarence, Welder Wildlife Foundation, P. 0. Box 1400, S inton, Texas 78387 Cottrell, George William, Rt. 2, Hillsboro, N.H. 03244 Cottrille, Mrs. W. Powell, 6075 Brown's Lake Rd., Jackson, Mich. 49203 Cottrille, W. Powell, 6075 Brown's Lake Rd. , Jackson, Mich. 49203 Cowley, Lee Ann, 1 Cedar Springs Circle, Southington, Conn. 06489 Cox, Geraldine H(ollon), Rt. 1, Box 115^ Merritt, N. C. 28556 1944 1954 1955 1956 1959 1967 1966 1957 1923 1954 1966 1945 1937 1962 1962 1959 1970 1970 1970 1949 1962 1952 1970 1929 1941 1950 1949 1968 1963 11a Cracraft, Joel Lester, Dept, of Anatomy, Univ. of Illinois at the Medical Center, Chicago, 111. 60680 Crafts, Roger C(onant), Jr., Evermann Apts. W-462, Bloomington, Ind. 47401 **Crawford, Alan, Jr., White Horse Rd. , Devon, Pa. 19333 Creighton, Phillip D. , Route 5, Box 242, Fort Collins, Colo. 80521 * Crockett, David B. , 2128 Fry St., Roseville, Minn. 55113 Croft, Joseph E. , 2366 Gladstone Ave. , Louisville, Ky. 40205 Crosby, Gilbert T(urner), 39 N. W. 39th Ave., #3, Gainesville, Fla. 32601 Cross 1 n. R i chard s.. 1719 N. Huachuca , Tucson, Ar i z. 85705 Crowder, Orvi 1 le w.. Harper ' s Ferry, W. Va. 25425 C rowel 1, John B. , Jr. , 1185 Ha 1 1 i nan Circle, Lake Oswego, Oregon 97034 Cruickshank, Allan Dudley, 1925 South Indian River Dr., Rockledge, Fla. 32955 Cruz, Alexander, Dept, of Zoology, Univ. of Florida, Gainesville, Fla. 32601 Cullen, Peter, 5115 Graceland, Indianapolis, Ind. 46208 Cunningham, James W. , 3009 East 19th Terrace, Kansas City, Mo. 64127 Cunningham, Richard L. , Organ Pipe Cactus National Monument, Box 38, Ajo, Ariz. 85321 **Curry, James R. , 1303 George St., Norman, Okla. 73069 Cuthbert, Nicholas L. , Biology Dept., Central Michigan Univ., Mt. Pleasant, Mich. 48858 Cutler, Mrs. Betsy D. , 25 Cerritos Ave., San Francisco, Calif. 94127 Cutler, David A., 1110 Rock Cr. Drive, Wyncote, Pa. 19095 Cutts, Ernest (Allen), 1466 South Edgewater Dr., Charleston, S. C. 29407 1961 1967 1949 1968 1955 1956 1970 1968 1961 1952 1939 1970 1956 1935 1964 1968 1950 1959 1963 1967 Dana, Edward Fox, 57 Exchange St., Portland, Maine 04111 1939 * Danforth, Edward J(oseph), 20 Westwood Dr., Orono, Maine 04473 1965 Daniels, Estrilla (Myrtle), 270 S. Prospect St., Ravenna, Ohio 44266 1959 Daniels, Mildred, Boxwood, Booth Rd. , Mentor, Ohio 44060 I959 Darby, Richard T. , 36 Prospect St., Sherborn, Mass. 01770 1948 * Darden, Mrs. Colgate W(hitehead), Flicker Point, Algonquin Park, Norfolk, Va. 23505 1943 Dater, Eleanor E. , 259 Grove St., P. 0. Box 111, Ramsey, N.Y. 07446 1949 Davant, Mary, 861 N. McLean Blvd., Memphis, Tenn. 38107 1952 Davenport, Mrs. Allan G., 39 Walcott Ave., James- town, R. I. 02835 1959 Davey, Winthrop N(ewbury), 495 Hillspur Rd. , Ann Arbor, Mich. 48105 1941 Davis, Clifford Vernon, Montana State Univ., Bozeman, Mont. 59715 1945 12a DaviSj David E(dward), Dept, of Zoology, P. 0. Box 5577j State College Station, Raleigh, N. C. 27607 1940 Davis, Frederic W(hitlock), Box 30, Ashby, Mass. 01431 1970 Davis, Jane S(trahn), Box 38, White Marsh, Va. 23183 1948 Davis, John, Hastings Natural History Reservation, Star Rt., Box 80, Carmel Valley, Calif. 93924 I939 Davis, L(ouie) Irby, 2502 Keating Lane, Austin, Texas 78703 I933 Davis, Rolph, King City, Rt. 1, Ont., Canada I963 * Davis, William B. , Dept, of Wildlife Management, College Station, Texas 77841 I938 * Davis, William F(ranklin), 423 West 46th St., Ashtabula, Ohio 44004 I947 Davis, W. Marvin, School of Pharmacy, Univ. of Mississippi, University, Miss. 38677 I956 Davy, Roger H(ewson), 5547 North 13th As/e., Phoenix, Ar i z. 850 13 1957 Dean, Mrs. Blanche E(vans), P. 0. Box 14, Goodwater, Ala. 35072 1947 DeFoe, Donald H. , 24 Pressley Rd. , Asheville, N. C. 28805 1962 Dehner, Eugene W(illiam), St. Benedict's College, Atchison, Kan. 66002 1944 * Delacour, Jean Theodore, c/o American Museum of Natural History, Central Park West at 79th St., New York, N. Y. 10024 1944 Delaney, Deborah Anne, 1404 S. Anthony Ave. , Columbia, Mo. 65201 1970 Del Vecchio, Philip J(oseph), 971 East 22nd St., Peterson, N. J. 07513 1969 Dennis, James R(obert), 2771 S. E. 15th St., Pompano Beach, Fla. 33062 I96I Dennis, John V(alue), Box 389, Leesburg, Va. 22075 1964 Denton, J(ames) Fred, 529 Henderson Drive, Augusta, Ga. 30904 1935 de Schauensee, Rodolphe Meyer, Devon, Pa. 19333 1945 Deters, James R(ay), 1404 S. I6th, Mattoon, 111.61938 1967 Devitt, 0. E. , 263 Ruggles Ave., Richmond Hill, Ont., Canada I966 Dexter, Ralph W. , Dept, of Biology, Kent State Univ., Kent, Ohio 44240 1958 * Dick, John Henry, Dixie Plantation, Meggett, S. C. 29460 1949 * Dickerman, Robert W(illiam), Dept, of Microbiology, Cornell Univ. Medical School, New York, N.Y. 10021 1955 * Dickerson, Stanley S. , 1490 Long Rd. , Somerville, N. J. 08876 1959 Dickinson, J(oshua) C(lifton), Florida State Museum, Univ. of Florida, Gainesville, Fla. 32601 1939 Didiuk, Andrew Basyl, 1057 Inkster Blvd., Winnipeg 14, Manitoba, Canada 1969 Dinsmore, James J(ay), Dept, of Zoology, Univ. of Florida, Gainesville, Fla. 32601 1969 Divoky, George J(oseph), Jr., Dept, of Zoology, Michigan State Univ., 220 Natural Science Bldg., East Lansing, Mich. 48823 1970 Dixon, James B(enjamin), 2266 Cranston Dr., Escondido, Calif. 92025 . 1936 Dixon, Keith Lee, Dept, of Zoology, Utah State Univ., Logan, Utah 84321 ^ 1946 Doerder, F(rancis) Paul, Rt. "i, Boone, Iowa 50036 1965 13a * Doering, Hubert R. , 900 Palmer Rd., Bronxville, N. Y. 10708 Doerr, Phillip D(avid), Rt. 1, Sun Prairie, Wise. 53590 Donald, Mary (Frances), 6918 Belmont Lane, Milwaukee, Wise. 53217 Dorsey, George A., Darlington School, Rome, Ga. 30161 Doscher, Mrs. Lois T., 1 Lando Dr., Manning, S.C. 29102 Doubleday, David N. , Box 427 Sharon, Conn. O66O69 Douglas, Herbert Edward, 910 Palmer Rd., Apt. 5, Oxon Hill, Md. 20022 **Douglass, Donald W. , Game Div. , Michigan Dept, of Natural Resources, Lansing, Mich. 48926 Dow, Douglas D(avid), Dept, of Zoology, Univ. of Queenland, Brisbane, Australia 4067 Dowdy, Quentin B(ertram), 3630 Sharpe Ave. , Memphis, Tenn. 38111 Downs, Mrs. James R(euel), Glebe Farm, South Londonderry, Vt. 05155 Drewien, Roderick, Idaho Cooperative Wildlife Re- search Unit, College of Forestry, Wildlife & Range Sciences, Unlv. of Idaho, Moscow, Idaho 83843 Drinkwater, Howard (Frank), Rt. 2, Hickory Run, Califon, N. J. 07830 * Drury, William H(olland), Jr., Drumlin Farms, South Lincoln, Mass. 01773 Dubke, Kenneth Howard, 3302 Navajo Dr., Chattanooga, Tenn. 37411 DuBois, Charlotte A., 9 Willow St., Princeton, N. J. 08540 Duce, Mrs. Elizabeth R(andall), P. 0. Box 396, Damar i scotta, Maine 04543 Duchein, Anette, Box 431, Spartanburg, S.C. 29301 Dudiak, John, 330 Norfolk Ave., Loraine, Ohio 44055 Duebbert, H(arold F(ranklln), 713 15th St., S. E. , Jamestown, N. D. 58401 Duffield, Mrs. John W. , 215 Furches St., Raleigh, N. C, 27607 * Dugan, William Dunbar, 26 Hampton Brook Drive, Hamburg, N. Y. 14075 du Mont, Helen, Wilmington, Vt. 05363 Du Mont, Philip A(tkinson), 4114 Fessenden St., N.W., Washington, D. C. 20016 **Duncan, Robert, 1151 Fulton Ave., San Antonio, Texas 78201 Dunham, David W(arren), Dept, of Zoology, Univ. of Toronto, Toronto 5, Ont., Canada Dunstan, Thomas C. , Dept, of Biological Sciences, Western Illinois Univ., Macomb, 111. 61455 Dusi, Julian L(uigi), Dept, of Zoology & Entomology, Auburn Univ., Auburn, Ala. 36830 * Duvall, Allan J. , Patuxent Research Center, Laurel, Md, 20810 Dyer, M(elvin l(vor). Box 374, Sandusky, Ohio 44870 Dyer, William A., T imber 1 ane, Rt. 2, Lake Wales, Fla. 33853 Dzubin, Alex, Canadian Wildlife Service, Univ. of Saskatchewan, Saskatoon, Sask. , Canada 1945 1967 1951 1956 1967 1970 1 966 1929 1963 1966 1959 1965 1954 1951 1960 1962 1959 1965 1967 1957 1948 1945 1970 1928 1956 1962 1970 1941 1958 1963 1947 1956 14a Easterla, David Arlen, 403 S. Frederick, Maryville, Mo, 64468 ^ Eastman, John A., 77 1 W. Main St., Apt. 8, Kalamazoo, Mich. 49006 * Eastman, Whitney H(askins), 7000 Valley View Rd., Minneapolis, Minn. 55435 * Eaton, Stephen W(oodman), Dept, of Biological Sciences, St. Bonaventure Univ. , St. Bonaventure, N.Y. 14778 Eberly, Lee, Rt. 2, Box 94, Vermillion, S, D. 57069 Eckelberry, Don R(ichard), I80 Woodsome Rd., Babylon, N. Y, 11702 ^ Eddinger, C. Robert, Dept, of Zoology, Univ. of Hawaii, Honolulu, Hawaii 96822 Eddy, Garrett, 4515 Ruffner St., West, Seattle, Wash. 98199 * Edeburn, Ralph M(ilton), Dept, of Zoology, Marshall University, Huntington, W. Va. 25701 * Edwards, Ernest P(reston), Sweet Briar, Va. 24595 Edwards, James L. , c/o Manager, 81 Gordonhurst Ave. , Upper Montclair, N. J. 07043 * Edwards, K(enneth) F(rederick), 424 Southwood Dr., Kingston, Ont., Canada Edwards, R(oger) York, Canadian Wildlife Service, 400 Laurier Ave., West, Ottawa 4, Ont., Canada Eiseman, Ralph M(ilton), Highland Park High School, 433 Vine Ave., Highland Park, 111. 60035 * Eisenmann, Eugene, 110 West 86th St., New York, N. Y, 10024 Ekblaw, George Elbert, 511 West Main St., Urbana, 111. 61801 Ekdahl, Conrad H(oward), Box 1246, Daytona Beach, Fla. 32015 Ekiund, Carl M(ilton), Rocky Mountain Laboratory, Hamilton, Mont. 59840 * Elder, William H(anna), Wildlife Conservation Bldg., Univ. of Missouri, Columbia, Mo. 65201 Ellarson, Robert S(cott), 215 Russell Laboratory, Madisoft, Wise. 53706 Elliott, Bruce G. , 20 E. Main St., #68, Los Gatos, Calif. 95030 Ely, Charles A(delbert), Dept, of Zoology, Fort Hayes Kansas State College, Hays, Kan. 67602 Emerson, Alica M(arieJ, 1425 Luther, Emporia, Kan. 6680 1 Emerson, Anne Ellen, 1425 Luther, Emporia, Kan. 66801 Emerson, David L(owell), 1144 Burt St., Taunton, Mass. 02780 Emerson, William S(tevenson), 22 Thoreau Rd. , Lexington, Mass. 02173 Emigholz, Mrs. Lawrence F. , 13634 Northwood Rd. , Novelty, Ohio 44072 * Emlen, John Thompson, Jr., Dept, of Zoology, Univ. of Wise., Madison, Wls. 53706 Emlen, Stephen T(hompson), Section of Neurobiology S- Be- havior, Cornell Univ., Ithaca, N.Y. 14850 Emmons, Jonathan C. , 305 Rolfs Hall, Univ. of Florida, Gainesville, Fla. 32601 Enderson, James Harris, Dept, of Biology, Colorado College, Colorado Springs, Colo. 80903 1959 1964 1941 1942 1970 1948 1968 1947 1947 1947 1947 1953 1948 1955 1942 1914 1949 1945 1938 1948 1963 1960 1970 1970 1939 1953 1970 1936 1964 1970 i960 15a Enright, Christine A(nn), Col. Coop. Wildlife Research Unit, Colorado State Univ., Fort Collins, Colo. 80521 1969 Epple, A. C. , 602 Sunrise Ave. , Park Ridge, Stevens Point, Wise. 5A-481 1963 Erickson, Elsie C. , Box 114, Allport, Pa. 16821 1951 Erickson, Homer T. , 1409 N. Salisbury St., West Lafayette, Ind. 47906 1959 Erickson, John E(ugene), Dept, of Zoology, Univ. of Washington, Seattle, Wash. 98105 1965 Erickson, John G(erard), 1344 S. Second St., Still- water, Minn. 55082 1949 Erickson, Mary M(arilla), Santa Barbara College, Univ. of California, Santa Barbara, Calif. 93106 1930 Erickson, Ruth C. , 3166 Merrill, Apt. 204, Royal Oak, Mich. 48072 ^ 1961 Erskine, A(nthony) J(ohn), 1215 Agincourt Rd. , Ottawa 5, Ont., Canada 1969 Erwin, William J(arnes), Jr., c/o Dan River Mills, Inc., Danville, Va. 24541 1968 Evans, Monica A(nn), 1437 Knol Iwood Ave., Kalamazoo, Mich. 49007 1955 Evenden, Fred G(eorge), 7805 English Way, Bethesda, Md. 20034 1948 Ewald, Robert Charles, Holy Cross Mission Center, 4301 Harewood Road, N. E. , Washington, D. C. 20017 I966 Ewer, Jack, Casilla 179“D, Santiago, Chile 1969 Eyer, Lester E. , 5355 Blue Heron Dr., Rt. 3, Alma, Mich. 48801 1954 Eynon, Alfred E. , 5 Beach Rd., Verona, N. J. 07044 1947 Eyster, Marshall Blackwell, 226 Monteigne Dr., Lafayette, La. 70501 1947 Faaborg, John R(aynor), 777 Pammel Court, Ames, Iowa 50010 1964 Fairfield, George M. , 490 Merton St., Toronto 7, Ont. , Canada 1 962 Fales, John H(ouse), Ridge Rd. , Neeld Estate, Huntington P. 0. , Md. 20639 1939 Fall, Bruce A., 148 Blueberry Lane, West Lafayette, Ind. 47906 I968 Falls, J. Bruce, Dept, of Zoology, Univ. of Toronto, Toronto 5j Ont., Canada 1948 Farrand, H. F. , 7 Guest Lane, Wilmington, Del.l9809 1950 Farrel, Franklin, III, Northrup Rd., Woodbridge, Conn. 06525 1959 Faust, Warren R. , 1100 W. Chester Pk. , W. Chester, Pa. 19380 1967 Fawks, Elton, 510 Island Ave., East Moline, 111. 61244 1951 Feduccia, J(ohn) Alan, Dept, of Biology, Southern Methodist Univ., Dallas, Texas 75222 I966 Feigley, Margaret D. , 56I6 Oleatha, St. Louis, Mo. 63139 1944 Feinsinge.r, Peter, Laboratory of Ornithology, Cornell Univ., Ithaca, N.Y. 14850 1970 Feist, Irving, 48 Park Place, Newark, N. J. 07102 1958 Ferguson, David S(owers), Rt. 1, Box 128, Philipsburg, Pa. 16866 I962 Fernandez, Gilbert F. , P. 0. Box 53, Dartmouth, Mass. 02714 1968 ffrench, Richard Po , St. Peter's School^ Texaco Trinidadj Inc., Po I nte-A-P i er re, Trinidad Fiala, Kent Lee, Box 45, Beatrice, Neb. 683 10 Ficken, Robert W. , Dept, of Zoology, Univ. of WI scons I n-Mi i waukee, Milwaukee, Wise. 53201 Fiedler, Lynwood Alvin, 6075 Red Bank Rd. , Rt. 2, Galena, Ohio 43021 Fillebrown, T(homas) Scott, R. F. D. , Lakeville, Conn. 06039 Finucane, Thomas Wellington, 1434 Watauga St., Kingsport, Tenn. 37664 Fish, William Ralph, 1863 Watt Ave., #24, Sacra- mento, Calif. 95825 * Fisher, Harvey l(rvln). Dept, of Zoology, Southern Illinois Univ., Carbondale, 111. 62903 Fisher, James (Maxwell) (McConnell), Ashton Manor, Ashton, Northampton, England **FIsk, Mrs. Bradley, I7IOI S.W. 284th St., Homestead Fla. 33030 Fiske, John, Petersham, Mass. 01366 FIske, Mrs. John, Petersham, Mass. 01366 FIsler, George F. , Dept, of Biology, San Fernando Valley State College, Northridge, Calif. 91324 Fitter, Richard S(idney) R(ichmond), Drifts, ChInnor Hill, Oxford, England * Fleugel, James Bush, Box 53, Grand Beach, Mich. 49118 Flock, Warren L(incoln), Dept, of Electrical En- gineering, Univ. of Colorado, Boulder, Colo. 80302 Florant, Greg, 963 Oregon Ave., Palo Alto, Calif. 94303 Fogarty, Michael John, 26o6 NE 17th Terrace, Gaines- ville, Fla. 32601 Follen, Don G. , Sr., Rt. 2, ArpIn, Wise. 54410 Foote, R(obert) T(haddeus), P. 0. Box 737, Milwaukee, Wise. 53201 Ford, Norman L(ee), Biology Dept. , St. John's Univ., Col 1 egev i 1 1 e, Minn. 56321 Ford, Thomas R(obert), 142 E. Warren St., Box 281, Cadiz, Ohio 43907 Forsyth, Bill (y) J(oe), Dept, of Biology, Indiana Univ. Southeast, Jeffersonville, Ind. 47130 Forsythe, Dennis M(artin), Dept, of Biology, The Citadel, Charleston, S. C. 29409 **Foster, Thomas Henry, Box 397^ Bennington, Vt. 05201 Foster, William L(uther), Box 598, Alaska 99762 Fox, Adrian C. , P. 0. Box 327, Leeds, N. D. 58346 Fox, Glen A., 65 Grange St., Guelph, Ont. , Canada Fox, Robert P. , 120 Thaxter St., HIngham, Mass. 02043 Fraga, Rosendo M(anuel), Callao 1502, Buenos Ai res. Argent I ne Francis, William J., P. 0. Box 374, Sandusky, Ohio 44870 . ,, , Francq, Glenn Earle, 1818 College, Baldwin, Kan. 66006 * Franks, Edwi n C( 1 ark), Rt. 1, Colchester, 111.62326 Freder i ckson, Richard William, St. Joseph's College, City Ave. at 54th St., Philadelphia, Pa. 19131 Fredrickson, Leigh, Gaylord Memorial Laboratory, Univ. of Missouri, PuxIco, Mo. 63960 _ Freeman, William, Shore Drive, Harbor Springs, Mich. 49740 Freemyer, Howard R. , Box 21, Jayton, Texas 79528 1965 1 966 1957 1965 1951 i960 1950 1949 1960 1 966 1 966 1966 1954 1966 1942 1968 1970 1968 1964 1957 1959 1958 1968 1962 1950 1961 1937 1960 1953 1969 1967 1970 1964 1947 1963 1959 1966 17a Freese, Gail (Miriam), 69 West Broadway, Bangor, Maine 04401 1968 Fretweil, Stephen DeWitt, Div. of Biology, Kansas State Univ. , Manhattan, Kan. 66502 1958 Fries, Waldemar Hans, 86 Cushing St., Providence, R. I. 02906 1947 Fritts, Steven Hugh, 20 South Hill Ave. , Fayette- ville, Ark. 72701 1970 Fritz, Arnold W(arren), 7210 Hoverland N.W., Massillon, Ohio 44646 1964 * Frohling, Robert C(harles), 2480 Bowen Rd. , Howell, Mich. 48843 1949 Frye, 0. Earle, Jr., Game & Fresh Water Fish Com- mission, Tallahassee, Fla. 32304 1940 Fuller, A(nne) Verne, 914 Lee Barton Place, Kala- mazoo, Mich. 49007 1952 Furniss, W. Todd, 3422 Dent Place, N. W. , Washing- ton, D. C. 20007 1961 Gabrielson, Ira N(oel), 2500 Leeds Rd. , Oakton, Va. 22124 1913 Gaede, Adel a, Wade Park Manor, Room 414, Cleveland, Ohio 44106 1951 Galley, Janet, Rt. 4, Box 98 A, Norman, Okla 73069 1964 **Gaillard, M. Wilson, 319 So. Sage Ave., Mobile, Ala. 36606 1970 Galati, Robert, 638 West Ave., Fullerton, Calif. 92632 1955 Galipeau, Paul R(eneau), P. P. Box 295, Belchertown, Mass. 01007 1970 Galley, John E(dmond), P. 0. Box 1346, Kerrville, Texas 78028 1945 Gamester, Mrs. Ruth M. , 95 Bayside Rd. , Greenland, N. H. 03840 1967 * Garmell, R(obert) T(heodore), Kenmare, N. D. 58746 1943 * Ganier, Albert F(ranklin), 2112 Woodlawn Dr., Nashville, Tenn. 37205 1915 Garlick, James H. , III, 120 Arboretum Rd. , Richmond, Ind. 47374 I966 Garrett, Nancy N. , 3111 Riviere du Chien Loop West, Mobile, Ala. 366I9 i960 Garrey, Mrs. ^Walter E. , 39 Orchard Ave., Waban, Mass. 02168 I959 Garrity, Devin A(dair), 682 Forest Ave., Rye, N. Y. IO58O 1949 Gashe, Mrs. Arthur S. , 1297 N. E. 103rd St., Miami Shores, Fla. 33138 I956 Gaschen, Ronald C(aryl), 30 Roxborough St., East, Toronto 5, Ont., Canada I96I Gates, Doris (Berta), Chardon State College, Chardon, Neb. 69337 1948 Gates, John M. , Dept, of Wildlife 6- Fisheries Science, So. Dakota State Univ., Brookings, S. C. 57006 1957 Gaunt, Abbot S. , College of Biol. Sciences, Ohio State Univ., 1735 Neil Ave., Columbus, Ohio 43210_ 1965 Gauthreaux, Sidney A(nthony), Jr., Zoology Section, Div. of Biology, Clemson Univ., Clemson, S. C. 2963 1 I967 I8a Gaymer, Rosemary D(esiree), Apt. 1005. 485 Huron St.. Toronto 3. Ont. . Canada Gehman. Richard. 216 Main St.. Venica. Cal if. 90291 Geist. Robert M(iller). 220 Ransom St.. Chapel Hill, N. C. 27514 Gensch. Robert Henry. 3100 Girard Ave. S. , Apt. 307. Minneapolis. Minn. 55408 George. John L(othar). Room 4. Ferguson Bldg,. School of Forest Resources. Penna. State Univ. , Univ. Park. Pa. 16802 George. William G(ordon). Dept, of Zoology. Southern Illinois Univ.. Carbondale. 111. 62901 Gerstel 1. Richard. 1046 Buchanan Ave.. Lancaster. Pa. 17603 Giesel. Mrs. James T. . 318 Ash Street. Park Forest. 111. 60466 Gifford. Harold. 3636 Burt. Omaha. Neb. 68103 Gillette. Mrs. Edmond S. . Jr. 3212 Jackson St.. San Francisco. Calif. 94118 Glanzman. Terry. Rt. 2. Box k3, Mondovi. Wise. 54755 Glenny. Fred H(arry). Dept, of Biology. Fairleigh Dickinson Univ.. Madison. N. J. 07940 Glick. Bruce. Box 5188. State College. Miss. 39762 Glover. Fred A(rthur). Colorado Cooperative Wildlife Research Unit. Colorado State Univ.. Coop. Unit Bldg.. Fort Collins. Colo. 80521 Gobeil. Robert Eugene. P. 0. Box 402. Biddeford. Maine 04005 Gochfeld. Michael. Rt. 1. Lexington Ave.. Mohegan Lake. N.Y. 10547 Goddard. Stephen V.. Biology Dept.. Wisconsin State Univ.. River Falls. Wise. 54022 Goebel. Herman J(ohn). 78-52 80th St.. Brooklyn. N.Y. 1 1227 Goldman. Peter C. . 5400 Cleveland Ave.. Columbus. Ohio 43229 Goldstein. Raymond B(ernard). Dept, of Zoology. Univ. Nebraska. Lincoln. Neb. 68508 Good. Ernest E(ugene). School of Natural Resources. 224 Lord Hall. Ohio State Univ.. Columbus. Ohio 43210 Goodpasture. Mrs. Ernest W. . 3407 Hopkins Lane. Nashville. Tenn. 37212 * Goodwin. Clive Edmund. 11 Westbank Cresent. Weston. Ont. . Canada Gos 1 i n. Charles R(ussell). 414 Baldwin Drive. Lancaster. Ohio 43130 Gottschall. Mrs. Donald A.. Rt. 1. Box 120 A. F r i endsvi 1 1 e. Pa. 18818 Gourley. Robert S(teven). Fernow Hall. Cornell Univ.. I thaca. N. Y. 14850 * Graber. Richard R. . 109 W. Franklin. Urbana. Ml. 61801 Grambor. John Robert. 745B Owens Ave.. Albany. Ga. 31703 . . , Grant. Cleveland P(utnam). 245 Davis St.. Mineral Point. Wise. 53565 „ . , Grant. Gilbert S(pencer). Rt. 1j Box 363j Sneads Ferry. N. C. 28460 1964 1959 1 966 1939 1939 1957 1939 1965 1936 1967 1968 1958 1942 1947 1963 1961 1965 1946 1970 1970 1937 1950 1952 1940 1968 1968 1949 1970 1928 1967 19a Graulj Walter D. , Depto of Ecology £• Behavioral Biology^ Bell Museum of Natural History, Univ. of Minnesota, Minneapolis, Minn. 55^55 1968 * Greeley, F red ( er i ck) , Dept, of Forestry & Wildlife Management, Univ. of Massachusetts, Amherst, Mass. 01003 19^2 Green, Mrs. Janet Curtis, 9773 North Shore Dr., Duluth, Minn. 55804 I960 Green, N(orman) Bayard, Dept, of Biological Sciences, Marshall Univ., Huntington, WVa. 25701 1943 Greenberg, Robert E. , 279 Natural Resources Bldg., Illinois Natural History Survey, Urbana, 111. 61801 1967 Greene, Mrs. Charles W(illiam), 505 North Lake Shore Drive, #5505, Chicago, 111. 606II 1968 * Greenewalt, Crawford H(allock), Greenville, Wilmington, Del. I9807 I960 Greenig, Mrs. Patricia, 5I67 Winterton Drive, Fayetteville, N.Y. I3066 1957 Greenlaw, Jon S(tanley), 5 Etna Lane, Dix Hills, N.Y. 11746 1965 Greenwalt, Leon, 911 S. Seventh St., Goshen, I nd. 46526 1953 Gregg, Larry E. , Box D, Horicon, Wis. 53032 1970 Greij, Eldon D(ean), Dept, of Biology, Hope College, Holland, Mich. 49423 1963 Greiner, Dale W(arren), 1825 Arbordale, Ann Arbor, Mich. 48103 1965 Griffee, W(illet) E. , P. 0. Box 637, Waynesboro, Miss. 39367 1947 Griffin, William W(elcome), 1330 West Garmon Rd. , N.W., Atlanta, Ga. 30327 1946 Griffith, George F. , Box 468, Hebron, Ohio 43025 I968 Griffith, Roger Braden, 329 Elm St., Sharon, Pa. 16147 1962 Grimes, S(amuel) A(ndrew), 4627 Peachtree Circle E, Jacksonville, Fla. 32207 1924 Grimm, William C(arey), 15 Strawberry Dr., Rt. 9, Greenville, S. C. 29609 1939 * Grinnell, Lawrence I(rving), 710 Triphammer Rd. , Ithaca, N.Y. 14850 1939 Groesbeck, William M(aynard), 376 Seneca Rd., Hornell, N.Y. 14843 1947 Grout, W(esley) R(obert), P. 0. Box 518, Nassau, Bahamas I969 Grube, G(eorge) E(dward), Biology Dept., Dana College, Blair, Neb. 68OO8 1948 **Gruson, Edward S(tanley), 109 Heath's Bridge Rd., Concord, Mass. 01742 1965 Gudmundson, Finnur, Museum of Natural History P. 0. Box 532, Reykjavik, Iceland 1964 Bullion, Gordon W( right). Forest Research Center, Univ. of Minnesota, Cloquet, Minn. 55720 1947 Gunderson, Harvey Lorraine, State Museum, Morrill Hall, Univ. of Nebraska, Lincoln, Neb. 68508 I941 * Gunn, W(illiam) W(alker) H(amilton), 155 Balliol St., Apt. 1605, Toronto 7, Ont. , Canada 1945 Gunther, Klaus, Wilseder Strasse 21, 1 Berlin 41, West Germany 1952 Guth, Robert wUyne), Rt. 1, Box 261, Eureka, 111. 61530 20a Guy, Thomas D., 55021 516 N. E. 3rd St., Faribault, Minn. Haas, George Hartmann, 339 Entomology Bldg., Unlv. of Minnesota, St. Paul, Minn. 55101 Hacker, Carl S(ldney), Dept, of Biology, Univ. of Notre Dame, Notre Dame, Ind. 46556 Hadley, Joel W. , Rt. 1, Arlington, Ind. 46104 Haffer, Jurgen H(ans), 950 Mockingbird Lane, Mobil Oil Co., P. 0. Box 900, Dallas, Texas 75221 Hagar, Joseph A., Pleasant St., Marshfield Hills, Mass. 02051 Hague, Florence S. , 3420 Shamrock Dr., Charlotte, N. C. 28205 * Hallman, Jack P. , Dept, of Zoology, Univ. of Wisconsin, Madison, Wise. Haines, Robert L(ee), 54 E. Main St., Moorestown, N. Jo 08057 Haines, T. P. , Biology Dept., Mercer Univ., Macon, Ga. 31207 Halberg, Mrs. Henry N. , 5809 North Country Club Blvd., Little Rock, Ark. 72207 Halbritter, Wesley E(ugene), 112 W. 42nd, Sioux Falls, S.D. 57105 Haldeman, John R. , Dept, of Zoology, Univ. of Arkansas, Fayetteville, Ark. 75701 Ha 1 d-Mortensen, Poul, Nordisk Kollegium, Strandboule- varden 32, 2100 Copenhagen Denmark * Hall, George A(rthur), Dept, of Chemistry, West Virginia Univ., Morgantown, WVa. 26506 Hall, Peter, 421 South Howes, Fort Collins, Colo. 80521 Hallauer, James E(dward), 338 North Hill Circle, Rochester, Mich. 48063 * Haller, Karl W. , 1114 Grant Drive, Sherman, Texas 75090 Hallman, Roy Cline, 800 Florida Ave. , Panama City, Fla. 32401 Hamel, Paul B(ernard), 1578-H Spartan Village, East Lansing, Mich. 48823 Hamerstrom, Frederick N. , Jr., Plainfield, Wise. 54966 Hamilton, Robert B(ruce), Dept, of Biological Sciences, Northwestern State College, Natchitoches, La. 71457 Hamilton, William J(ohn), Jr., 615 Highland Rd. , Ithaca, N.Y. 14850 Hamilton, William J(ohn), III, Zoology Dept., Univ. of California, Davis, Calif. 95616 Hamnett, William L. , State Museum, Box llGkl, Raleigh, N. C. 27611 Hamon, J. Hill, Dept, of Biology, Transylvania College, Lexington, Ky, 40508 Hampe, Irving E. , 5559 Ashbourne Rd., Halethorpe, Baltimore, Md. 21227 Hampson, James E(lmer), Rt. 3, Mendota, 111. 61342 Hancock, David, Wildlife Conservation Centre, Saanicaton, B. C. , Canada Handley, Charles O(verton), Jr., Div. of Mammals, U. S. National Museum, Washington, D. C. 20560 Handley, Charles O(verton), Sr., Rt. 2, Box 83W, Lewisburg, WVa. 24901 1967 1969 1961 1962 1969 1949 1931 1956 1947 1941 1953 1966 1970 1969 1946 1970 1958 1934 1928 1967 1934 1961 1933 1953 1964 1958 1945 1967 1962 1941 1925 21a Hanebrink, Earl L. , Box 67, Arkansas State Univ. , State University, Ark. 72467 **Hanley, Wayne, Hilicrest Dr., Harvard, Mass. 01451 Hanna, Wilson Creal, 712 North La Cadena Dr., Colton, Calif. 92324 . . Hanna, Wood, Sr., 110 E. Market St., Louisville, Ky. 40202 ^ ^ * Hanselmann, S(teven) Jay, Rt. 2, Box 59o, Eureka, Mo. 63025 Hansen, Thomas A., 438 Dauphine St., Apt. 3, New Orleans, La. 70112 1963 Harcus, John L. , Univ. of Toronto, Ramsey Wright Zoological Laboratories, 25 Harbord St., Toronto 5, Ont., Canada 1969 Harden, Walter D. , 1609 Rosemont Dr., Norman, Okla. 73069 1970 Hardy, (Cecil) Ross, California State College at Long Beach, 6101 East 7th St., Long Beach, Calif. 90804 1940 Hardy, John William, Moore Laboratory or Zoology, Occidental College, Los Angeles, Calif. 90041 1952 Harger, Elsworth M(ilton), Cusine Wildlife Experi- ment Station, Shingleton, Mich. 49884 1955 Hargrave, Lyndon L(ane), Prescott College, Box 2299j Prescott, Ariz. 86301 1952 **Harm, Ray, Chenoa, Kentucky 40925 1964 Harrell, Byron E(ugene), Dept, of Biology, Univ. of South Dakota, Vermillion, S. D. 57069 1964 Harrington, Brian A., Dept, of Zoology, Univ. South Florida, Tampa, Fla. 33620 1965 Harrington, Fred H(addox), 7824 Flourtown Ave. , Philadelphia, Pa. 19118 1970 Harrington, Winthrop Wendell, Jr., Rt. 1, Tower Rd., Lincoln, Mass. 01773 1969 **Harriot, Samuel C(arman), 200 West 58th St., New York, N. Y. 10019 1934 * Harrison, Ed N., 1100 Glendon Ave., Suite 1407, Los Angeles, Calif. 90024 1959 Harrison, Ha.l H. , Rt. 1, Box 1066, Sanibel, Fla. 33957 1941 Hart, Ethelwyn F. , 109 Sappington Dr., Columbia, Mo. 65201 1970 Hart, John A., 309 East Second St., Morris, Minn. 56267 1967 Harte, Kenneth J., Estabrook Rd. , Carlisle, Mass. 01741 1965 Harth, Marshall S(tephen), North Carolina Dept, of Mental Health, Div. of Research, Box 7532, Raleigh, N. C. 27602 I966 Hartman, Frank A(lexander), 183 West Como Ave., Columbus, Ohio 43202 I94I Hartman, George W(ilson), Gaylord Memorial Laboratory, Puxico, Mo. 63960 I97O * Hartshorne, Charles, 724 Sparks Ave., Austin, Texas 78705 I953 * Hartshorne, James M(ott), 108 Kay St., Ithaca, N.Y. 14850 1555 Hastings, Mrs. Watson B. , 18 Appleton Place, Dobbs Ferry, N.Y. 10522 1969 Hatch, Granville, Casa De Manana, La, Jolla, Calif. 92037 1964 Haugh, John R. , Box 486, Etna, N.Y. 13062 1964 1964 1969 1936 1964 1965 22a Hauser, Mrs. Roscoe, Jr., 811 North Alvernon, Apt. M , Tucson, Ariz. 85711 Haverschmidt, F(rancois), Wol f sku i 1 st raat 16, Ommen, Holland Havighurst, Linda, 2609 Bonfoy, Colorado Springs, Col. 80907 Howes, Robert L(ee), 709 DeBarr, Apt. 1, Norman, Oklahoma 73069 Hawksley, Oscar, Biology Dept., Central Missouri State College, Warrensburg, Mo. 64093 Hays, Herbert E. , 209 Queen St., Sh i ppensburg. Pa. 17257 Heatwole, Harold, Dept, of Zoology, Univ. of New England, Armidale, New South V^ales, 2351, Aust ra 1 i a Hebrard, James J(ack), 1260 Stanford Ave. , Baton Rouge, La. 70808 Hefley, Harold M(artin), 429 North 19th St., Beatrice, Neb. 68310 Heig, Vincent A(lan), Dept, of Biology, Wisconsin State Univ., Stevens Point, Wise. 54481 '**Heilner, George B. , St. Matthews Road, Box 80, Rt. 2, Chester Springs, Pa. 19425 He imerd i nger, H(oward) 0., 281 East 2nd St., Girard, Ohio 44420 Hein, Dale, Dept. Fishery S- Wildlife Biology, Colorado State Univ., Fort Collins, Colo. 80521 Heintzelman, Donald S. , 629 Green St., Allentown, Penna. 18102 Heiser, Joseph M(atthew), 1724 Kipling St., Houston, Texas 77006 Heithaus, E. Ray, Dept, of Biology, Stanford Univ., Stanford, Calif. 94305 Hellack, Jenna Jo, 204 N. Rennie, Tishomingo, Okla. 73460 * Helleiner, Frederick M. , 35 Kingswood Dr., Peterborough, Ont., Canada * Helms, Carl W. , Dept, of Zoology, Univ. of Georgia, Athens, Ga. 30601 Hembert, Frank K(ennedy) 1 I I, 2622 Meadow Lane, La Marque, Texas 77568 Henderson, David William, 1297 Del 1 wood Ave., Columbus, Ohio 43227 Henny, Charles J., Migratory Bird Populations Station, Laurel*.. Md. 20810 Heppner, Frank H. , Dept, of Zoology, Univ. of Rhode Island, Kingston, R. !. 02881 * Herbert, Mrs. Richard A., Middleton, Del. 19709 Hespenheide, Henry (August), 1315 Sussex Place, Norfolk, Va. 23508 . Hewitt, Oliver H. , Fernow Hall, Cornell Univ., Ithaca, N.Y. 14850 Heye, Paul L. , Dept, of Biology, Southeast Missouri State Coilege, Cape Girardeau, Mo. 63701 Heywood, Philip B. , 63 Beechmont St., Worcester, Mass. 01609 . . Hibbard, Edmund Arthur, 6OI So. University Dr., Fargo, N. D. 58102 Hickey, J(oseph) J(ames), 226 Russell Univ. of Wisconsin, Madison, Wi sc. Laborator i es, 53706 1955 1946 1970 1970 1948 1956 1963 1967 1942 1964 1970 1964 1963 1960 1939 1966 1968 1952 1952 1969 1969 1967 1969 1949 1958 1943 1961 1959 1950 1940 23a Hicks, Thomas W( i 1 1 iam). Dept, of English, Georgia State Univo, 33 Gilmer St., S. E. Atlanta, Ga. 30303 19^9 Higgins, Thomas Francis, Christian Ave. , Box 493, Stony Brook, N.Y. 11790 1947 Hill, Herbert O(liver), 2160 Ridgemont Dr., Los Angeles, Calif. 90046 1938 *Hill, Jul ian Werner, 1 106 Greenhi 1 1 Ave., Wilmington, Del. 19805 1935 **Hinds, Frank J. , 2906 Memory Lane, Kalamazoo, Mich. 49007 1935 Hinshaw, Thomas D., 1827 San Juan Ave., Berkeley, Calif. 94707 1926 Hochbaum, Hans Albert, Delta Waterfowl Research Station, Delta, Manitoba, Canada 1942 Hodess, Bruce H. , 13770 Ludlow, Oak Park, Mich. 48237 1968 Hodges, James, 203 Kahl Bldg., Davenport, Iowa 52805 1946 Hoelzle, Jean M. , 2323 Milbourne, Flint, Mich. 48504 1968 * Hoffman, L(ukas), Station Biologique de la Tour du Valat, Le Sambuc, B. d. Rh. , France 1955 Hofsjund, Pershing B(ernard), Biology Dept., Univ. of Mi nn. “Du 1 uth, Duluth, Minn. 55812 1944 Hoiberg, Arnold, Valhalla Rd. , Rt. 1, Box 719j Montville, N. J. 07045 1951 * Holcomb, Larry C. , Biology Dept., Creighton Univ., Omaha, Neb. 68131 1964 Holden, Mrs. David J., Rt. 1, Box 80, Brookings, S. D. 57006 . 1953 * Holden, Fenn M(itchell), Wesley Manor, H-5, Jacksonville, Fla. 32223 1947 Hole, John J. , 1514 NW 27, Oklahoma City, Okla. 73106 1968 Holgersen, Norman Erik, Rt. 2, Box 310A, Smyrna, Del. 19977 1959 Holmes, Richard T. , Dept, of Biological Sciences, Dartmouth College, Hanover, N. H. 03755 1966 Holohan, Stewart, Apt. 407, 2166 Blvd. de Maison- neuve West, Montreal, P.Q. , Canada 1969 Holzbach, John E(dward), 229 Maywood Dr., Youngstown, Ohio 44512 1969 Hood, Larry L(ee), Box 478, Laurel, Md. 20810 1966 Hoover, Ernest Eugene, 1044 Webster St., N.W. , Grand Rapids, Mich. 49504 1964 Horton, Mrs. E. E. , 2445 7 Huron River Dr., Rockwood, Mich. 48173 1954 Hostetter, D(avid) Ralph, Eastern Mennonite College, Harrisonburg, Va. 22801 1937 Hough, Mrs. Eleanor Sloan, 1515 Mariposa Ave., Boulder, Colo. 80302 1941 * Houston, C(larence) Stuart, 863 University Dr., Saskatoon, Sask. , Canada 1948 Howard, Deborah V., 34 Fairfax St., West Newton, Mass. 02165 1966 Howe, Marshall A(therton), Univ. of Minnesota, James Ford Bell Museum of Natural History, Minneapolis, Minn. 55455 1969 Howe, Thomas, 137 Sarles Lane, P 1 easantvi 1 1 e, N.Y. 10570 1970 Howell, Joseph C. , Dept, of Zoology £- Entomology, Univ. of Tennessee, Knoxville, Tenn. 37916 1938 * Howell, Thomas R(aymond), Dept, of Zoology, Univ. of California, Los Angeles, Calif. 90024 I947 24a Hubbel, Peter, 2565 Elm Street, Tucson, Ariz. 85719 Hufstader, Richard Wayne, 818 No. Lacy, Apt. F, Santa Ana, Calif. 92701 Hughes, Gilbert C. , 111, Dept, of Botany, Univ. of British Columbia, Vancouver 8, B. C. Humphrey, Philip Strong, Museum of Natural History, Univ. of Kansas, Lawrence, Kan. 66044 Hundley, Mrs. Margaret H. , Box 158, Stoninqton, Maine 04681 Hunt, George L(ester), Dept, of P. S- E. Biology, Univ. of California, Irvine, Irvine, Calif. 92664 Hunt, James H. , Dept, of Zoology, Univ. of Cali- fornia, Berkeley, Calif. 94720 Hunt, L(awrence) Barrie, Zoology Dept., Eastern Illinois Univ., Charleston, 111, 61920 * Huntington, Charles Ellsworth, Dept, of Biology, Bowdoin College, Brunswick, Me, 04011 Huntley, C(larence) W(estley), 1037 Redwood St., Crete, Neb. 68333 Huntzicker, George F., 1705 Morton St., Ann Arbor, Mich. 48104 Hurley, George F. , 920 Hughes Dr., St. Albans, W, Va. 25177 Hurley, Nancy A., 1875 South Adams St., Denver, Colo. 80210 * Hurlock, Phyllis Lorraine, Rt. 1, Coatesville, Fla, 19320 Hyatt, Philip E(dward), Box 560, Yocum Hall, Fayette ville. Ark. 72701 1970 1970 1952 1948 1959 1959 1966 1954 1950 1966 1970 1963 1962 1959 1970 Ickes, Roy A(lan), Biology Dept., Washington S- Jefferson College, Washington, Pa. 15301 I966 Imhof, Thomas A(nthony), 1036 Pike Rd. , Birmingham, Ala. 35218 1950 Jacobs, Joseph A(rthur), 1928 Hi Merest Ave, , Pennsauken, N. J. O8IIO Jackson, Jerome A,, Dept, of Zoology, Mississippi State Univ., St. College, Miss. 39262 Jahn, Laurence Roy, 2435 Riviera Dr., Vienna, Va. 22180 * James, Douglas Arthur, Dept, of Zoology, Univ. of Arkansas, Fayetteville, Ark. 72703 James, William S(tuart), 1409 Crocus Rd., Knoxville, Tenn. 37919 James- Ve i tch, Elden A. ^ Rt. 5, Kelowna, B. C. Canada Janssen, Robert B. , 14321 Prince Place, Hopkins, Minn. 55343 * Jaques, Francis Lee, 10 East Oaks Rd. , North Oaks Farms, St. Paul, Minn. 55110 Jarosch, Conrad Herbert, Biology Dept., College of New Caledonia, 2901 20th Ave., Prince George, B. C. , Canada * Jehl, Joseph R. , Jr., Natural History Museum, P. 0. Box 1390, Balboa Park, San Diego, Calif. 92112 * Jenner, William A., 307 Alma St,, O'Fallon, 111. 62269 Jenni, Donald A(lison), Dept, of Zoology, Univ. of Montana, Missoula, Mont. 59801 1963 1969 1950 1946 1959 1965 1952 1939 1965 1953 1933 1958 25a * Jeter, Horace Hearne, 3709 Line Ave. , Shreveport, La. 71104 1950 Johns, Frederick L(ouis), Box 5577 Zool., North Carolina State College, Raleigh, N. C. 27607 1964 Johnsgard, Paul A(ustin), Dept, of Zoology & Physiology, Univ. of Nebraska, Lincoln, Neb. 68508 1959 Johnson, Albert George, Rt. 1, Box 66, Excelsior, Minn. 55331 ^ 1947 Johnson, Delos E. , 16419 Fernway Rd. , Shaker Heights, Ohio 44120 1964 Johnson, Ellis D. 3446 W. 84th Place, Chicago, 111. 60652 1969 Johnson, Gordon W(allace), I85 Horseneck Rd. , South Dartmouth, Mass. 02748 1964 Johnson, James Walters, 1421 Utah Ave. , S. E. , Huron, S.D, 57350 1970 Johnson, J(ohn) C( hr i stopher ), Jr., Biology Dept., Kansas State College, Pittsburg, Kan. 66762 1955 Johnson, Ned K. , Museum of Vertebrate Zoology, Univ. of California, Berkeley, Calif. 94720 1962 Johnson, Richard E. , Museum of Vertebrate Zoology, Univ. of California, Berkeley, Calif. 94720 1967 Johnson, Robert A., Rt. 11, Box 188, Bloomington, Ind. 47403 1930 Johnston, David Ware, Dept, of Zoology, Univ. of Florida, Gainesville, Fla. 32601 1943 Jones, H(arry) Lee, Dept, of Zoology, Univ. of California, Los Angeles, Calif. 90024 1967 Jones, Howard P(hilip;, Rt. 6, Box 119^ Frankfort, Ky. 40601 1965 Jones, John C(ourts), 5810 Namakagan Rd., Washington, D. C. 20016 1931 Jones, Rene N. , Dept, of Zoology, Univ. of Western Ontario, London, Ont., Canada 1969 Jones, Robert E(urfryn), 399 N. 25th St., Camp Hill, Pa. 17011 1967 Jones, Vincent C(lement), 7706 Meadow Lane, Chevy Chase, Md. 20015 1951 Joslin, James Kelvin, Biology Research Center, Michigan State Univ., E. Lansing, Mich. 48823 1970 Jubon, John M. , Millstone Rd. , P. 0. Box 16, E. Millstone, N. J. 08874 1951 Judge, James Duane, 1219 Prospect St., Lansing, Mich. 48912 I969 Julian, Paul R(owland), 1269 Chinook Way, Boulder, Colo. 80302 1968 Jung, Clarence (Schram), 6383 North Port Washington Rd., Milwaukee, Wise. 53217 1921 * Junkin, P(eter) David, The Narrows Rd. , Bedford Hills, N.Y. 10507 1963 Jurica, E. , St. Procopius College, Lisle, 111. 60532 1940 Kaesgen, Jacqueline Ann, 21472 Sheldon Rd. , Brookpark, Ohio 44142 I967 Kahl, M(arvin) Philip, 661 Rudder Rd. , Naples, Fla. 33940 1953 Kale, Herbert W(illiam), II, Entomological Research Center, Box 308, Vero Beach, Fla. 3296O 1957 Kalmbach, Edwin Richard, I6OI Mariposa Ave., Boulder, Colo. 80302 1926 26a Karr, James R(ichard), Dept, of Biology, Princeton Univ. , Princeton, N. J. 08540 Kaspar, John L(oren), 5765 Lake Rd. , Oshkosh, Wise. 54901 Kassoy, Irving, 235 South 4th St., Columbus, Ohio 43215 Kaufman, Gerald W(ayne), Dept, of Biology, Loras College, Dubuque, Iowa 52001 Keeton, '*'*■' 5 Snyder Heights Rd. , Ithaca, Keil, Julius J. , 33-4? 14th St., Long Island City, N. Y. Ill 06 * Keith, Allan R(eed), Blue Mill Road, New Vernon, N. J. 07976 * Keith, G. Stuart, 130 East End Ave. , New York, N. Y. 10028 Kelker, George H. , College of Natural Resources, Utah State Univ., Loqan, Utah 84321 Kelley, Neil Thomas, 3681 Forest Hill Drive, Bloom- field Hills, Mich. 48013 Kellogg, Mrs. Waters, 59 Phillips St., Andover, Mass. 01810 Kelso, Leon H(ugh), I60I Argonne Place, N.W., Apt. 35 1^ Washington, D. C. 20009 Kemnitzer, Allen E(dward), 969 Five Mile Line Rd., Webster, N. Y. 14580 Kena^a^ Eugene E. , 3309 Isabella Rd. , Midland, Mich. Kendeigh, S(amuel) Char les. Vivarium Bldg., Wright & Healey Sts., Univ. of Illinois, Champaign, 111. 61820 * Kennedy, Bruce A(lbert) H(amilton), 154 Fairway Dr., Apt. B, Columbus, Ohio 43214 Kennedy, Joseph Clark, 13717 Chef Mentour, Apt. 203, New Orleans, La. 70129 Kennedy^ Robert S(enior), 157 Queens Dr., West, Williams burg, Va. 23185 Kennedy, Stephen William, Apt. 3, Mt. Toby Apts, Rt. 47^ Sunderland, Mass. 01375 Kent, F. W. , 302 Richards St., Iowa City, Iowa 52240 **Kent, Richard J(erome), 2921 Main St., Bethlehem, Penna. 18017 Kenyon, Karl W(alton), U. S. F. W. S. Bldg. 192, Divo of Wildlife Research, N. A. S. Sand Point, Seattle, Wash. 98115 Kepler, Cameron B. , P. 0. Box 442, Palmer, Puerto Rico 00721 Kermott, L(ouis) Henry, II06 28th Ave. South, No. I6, Grand Forks, N. D. 58201 * Kersting, Cecil Carl, Field Research Laboratory, P. 0. Box 900, Dallas, Texas 75221 Kessel, Brina, Box 211, College, Alaska 99735 Kibler, Lewis F(oster), Box 5A-0, Rt. 2, Jamestown, N. Y. 14701 Kiblinger, Carrol E. , 6118 McCommas, Dallas, Texas 75214 Kidd, Paul J(ames) G(arland), P. 0. Box 518, Walker- ville 15^ Ont., Canada * Kieran, John, 25 Norwood Ave., Rockport, Mass. 01960 Kiff, Lloyd F(rancis), c/o Western Foundation of Vertebrate Zoology, 110 Glendon Ave., Los Angeles, Calif. 90024 1965 1947 1958 1966 1969 1959 1969 1960 1938 1951 1967 1930 1949 1949 1923 1947 1967 1970 1970 1951 i960 1948 1967 1970 1950 1946 1962 1957 1962 1942 1964 27a Kiff, Mrs. Maxine C. , Box 260, Ona, WVa. 25545 1959 Kildow, T(honnas) Monroe, Box 518, Tiffin, Ohio 44883 1948 * Kilham, Lawrence, Dept, of Microbiology, Dartmouth Medical School, Hanover, N. H. 03755 1952 **KIllip, Thomas, III, 525 East 68th St., New York, N. Y. 10021 1946 Killpack, Merlin L(eo), 1726 24th St., Ogden, Utah 84401 1950 King, John Arthur, Dept, of Zoology, Michigan State Univ., East Lansing, Mich. 48823 1947 Kinser, Glenn W(illiam), Biology Dept., Rider College, Trenton, N. J. 08602 1967 ^^Ki rk, Lester K(ing), 19520 Bretton Dr., Detroit, Mich. 48223 1954 Kirkland, Gordon L. , Jr., Dept, of Biology, Shippens- burg State College, Shippensburg, Penna. 17257 1968 Kirkland, Wallace W(illiam), Jr., 822 Linden Ave. , Oak Park, 111. 60302 1968 Kirkpatrick, Charles M. , Dept, of Forestry, Purdue Univ., West Lafayette, Ind. 47907 1948 Kirkpatrick, Ralph D(onald), Rt. 1, Osage Farm, Jonesboro, Ind. 46938 1970 Klaas, Erwin E. , Rockhurst College, Kansas City, Mo. 64110 1970 Kleen, Vernon M(elvin), P. 0. Box 1057, Carbondale, 111. 62901 1970 ■* Klelman, Joseph P. , 18915 Bedford Rd., Birmingham, Mich. 48009 1963 Klein, Richard P. , Atkins Rd. , Rt. 3, Geneva, Ohio 4404l 1966 l^leiner, Eugene S(hippen), P. 0. Box 589, Gambler, Ohio 43022 1967 Kletzly, Robert C(harles), 101 Randolph Ave., Elkins, W. Va. 26241 1948 * Klick, Wilma S. , 7111 Oakridge Ave., Chevy Chase, Md. 20015 1939 Klimstra, W(illard) D(avid), Coop. Wildlife Research Lab,, Southern Illinois Univ., Carbondale, 111. 62903 1958 Klonick, Allan S. , 111 Rowland Parkway, Rochester, N. Y. 14610 1941 Klonowski, Thomas J(oseph), 25 Bridgeman St., Buffalo, N. Y, 14207 1969 Knickmeyer, Robert R(ichard), 833 Lynn Haven Lane, Hazelwood, Mo. 63042 1965 Knight, Charles Harold, 20700 Gladstone Rd. , Warrens- ville Heights, Cleveland, Ohio 44122 1959 Knoblaugh, Mrs. Jean S. , Rt. 3, Box 271, Tiffin, Ohio 44883 1957 Knopf, Fred L(eRoy), Dept, of Medicine, U. S. A. Res. Inst. EnVo Med., Natick, Mass. 01375 1970 Koch, George, 370 Central Ave., So. Charleston, W. Va. 25303 1969 Koerker, Richard M(orton), 1119 Boren, #408, Seattle, Wash. 98101 1961 Kolb, C(harles) Haven, Jr., Rt. 1, Box 147A, Millers, Md. 21107 1937 **Koon, Mrs. Annette C(laudia), South Highway 51, Gainesville, Texas 76240 I965 **Kovach, Louis Edward, 1412 Newport Ave., Northampton, Pa. 18067 1970 28a 927 15th St., N. W. , Washington, D. C. Kramsr, Thoodorc C(hrlstian), Rt. 6, 1810 Warran Rd, , Ann Arbor, Mich. 48105 Krapu, Gary, Dept, of Zoology, Iowa State Univ. , Ames, Iowa 50010 Kraus, Douglas L(awrence), P. 0. Box 57, Kingston, R. 1. 02881 Krebs, Mrs. R. W. , 98 Druid Hill Rd. , Summit, N. J. 07901 Kricher, John C., Biol ogy Dept . , Wheaton Coll ege, Norton, Mass. 02766 Kreig, David C. , I9 Grove St., New Paltz, N.Y. 12561 Krohn, William (Barry), 216 Forestry Bldg., Univ. of Maine, Orono, Maine 04473 Kroodsma, Roger (lee). Biology Dept., Union Univer- sity, Jackson, Tenn. 38301 Kruczek, Ron, P. 0. Box 219, Colchester, 111. 62326 Krug, Howard H(enry), Chesley, Ont., Canada Krull, John N. , Dept, of Zoology, Southern Illinois Univ., Carbondale, 111. 629OI Kuhn, Kenneth H(erbert), Box 144, Star Rt. , Athelstan, Wise. 54104 Kulesza, George C(harles), 3014 N. Haussen Court, Ch i cago. Ml. 606 1 8 Kunkle, Donald E. , Oyster Research Laboratory Bivalve, N. J. 08301 Kyllingstad, Henry C. , 205 6th St., South, Marshall, Minn. 56258 Labisky, Ronald F. , Sect, of Wildlife Research, Illinois Natural History Survey, Natural Re- sources Bldg., Urbana, 111. 61801 Laitsch, Mrs. Nevada, MC 21, East Liverpool, Ohio 43920 Lakeman, Marcia, 1305 Providence Terrace, McLean, Va. 22101 Lamely, Larry William, Coop Wildlife Research Lab., Southern Illinois Univ., Carbondale, 111. 62901 Lamore, Donald Hart, 419 West Main St., Nevada, Mo. 64772 Lancaster, Christine, 52 Summit R'd., Keene, N. H. 03431 Lancaster, Douglas A(lan), Laboratory of Ornithology, Cornell Univ., Ithaca, N. Y. 14850 Lanyon, Wesley E(dwln), American Museum of Natural History, New York, N. Y. 10024 Lapham, Helen Stark, 304 East 73rd St., New York, N. Y. 10021 * Laskey, Mrs. Frederick Charles, Graybar Lane, Nashville, Tenn. 37215 Lawrence, Mrs. Louise de Kiri line, Pimisi Bay, Rt. 1, Rutherglen, Ont., Canada Lawson, Ralph, 42 Chestnut St., Salem, Mass. 01970 Laybourne, Mrs. Roxie Collie, Rt. 1, Box 104, Manassas, Va. 22110 Laymon, Stephon B. , Central Washington State College, Dept, of Biological Sciences, Ellensburg, Wash. 98926 Lea, Robert B(ashford), 1045 North Spring St., Elgin, 111. 60120 1947 1939 1967 1942 1946 1968 1959 1968 1965 1968 1944 1967 1949 1970 1956 1967 1956 1961 1966 1969 1942 1959 1949 1955 1970 1928 1946 1951 1967 1970 1940 29a Leavitt, Benjamin Burton, Dept, of Biology, Univ. of Florida, Gainesville, Fla. 32603 Leberman, Robert C(harles), Rt. 1, Saeger Hill, Meadville, Penna. 16335 Leek, Charles F. , Dept, of Zoology, Nelson Biol. Lab., Rutgers College, New Brunswick, N. J. 0«903 Lee, Darrell T. , 2037 E. 34th St., Tucson, Ariz. 85 7 1 3 Lee, Dwight R(ussell), I656 Ebert St., Winston" Salem, N. C. 27103 Leedy, Daniel L(oney), 10707 Lockridge Dr., Silver Spring, Md. 20901 LeFebvre, Eugene, Dept, of Zoology, Southern Illinois Univ., Carbondale, 111. 62901 Leffler, Sanford R{oss), 826 So. Osage #14, Ingle- wood, Calif. 90301 Legacy, Mrs. Gerald D. , River Rd. , North Bennington, vt. 05257 * Lehmann, Margaret C. , 7020 Jeffery Ave. , Chicago, 111. 60649 Leichtamer, James D. , 125 Harrison St., Magnolia, Ohio 44643 , , Lein, M(illard) Ross, Museum of Comparative Zoology, Harvard Univ., Cambridge, Mass. 02138 Leineke, Claude Edward, P. 0. Box 2112, North Canton, Ohio 44720 ^ Leopold, A(1do) Starker, U. C. Dept, of Agricul- ture, School of Forestry and Conservation, Berkeley, Calif. 94704 LeSassier, Mrs. Anne L. , 1611 W. Indiana, Midland, Texas 79704 Lesser, Frederick Henry, 804 Radnor Ave., Pine Beach, N. J. 08741 Lester, Mrs. Martha H. , U. S. U. Apts., #2A, Utah State Univ., Logan, Utah 84321 Leverett, Hollis D. , 21 Hampden St., Wellesley, Mass. 02181 Levi, Herbert W. , Museum of Comparative Zoology, Harvard Univ., Cambridge, Mass. 02138 Levy, Seymour H. , Rt. 9, Box 960, Tucson, Ariz. 85705 * Lewin, Mrs. Judith, P. 0. Box 868, Freeport, Grand Bahama Island, Bahamas Lewis, C. Bernard, The Science Museum, Institute of Jamaica, Kingston, Jamaica, B. W. I. Lewis, R. Alan, Dept, of Zoology, Univ. of Washing- ton, Seattle, Wash. 98105 * Lewis, Thomas J. , Jr. 2406 E. Columbia Ave., Davenport, Iowa 52803 Libby, Mark L. , New Harbor, Maine 04554 Lieff, Bernard C. , 841 Valetta St., London 74, Ont., Canada Lien, Mrs. Boyd M. , 5148 29th Ave., South, Minneapolis, Minn. 55417 * Ligas, Frank J., Rt. 2, Box I876, Naples, Fla. 33940 Ligon, J(ames) David, Dept, of Biology, Univ. of New Mexico, Albuquerque, N. M. 87IO6 Lincoln, Charles W. , 392 Highland Ave., Upper Montclair, N. J. 07043 Lindberg, Harold Ljoyd, 311 Emery Ave., Peshtigo, Wise. 54157 1947 1958 1970 1967 1962 1936 1953 1964 1969 i960 1968 1969 1970 1940 1957 1964 1965 1966 1949 1962 1962 1947 1967 1956 1963 1968 1944 1951 1962 1953 1962 30a L I tt 1 ef i e 1 Carroll Dwayne^ Rt. 1. Friona, Texas 79035 Livingston, John Allen, 27 Nanton Ave. , Toronto 287, Ont., Canada Livingston, Philip A(tlee), 620 Manor Rd., Nar- berth. Pa, 19072 Lloyd, C(lark) K. , 11 North Elm St., Oxford, Ohio 45056 Lloyd, Hoyes, 582 Mariposa Ave., Rockcliffe Park, Ottawa, Onto, Canada Loetscher, Freder ick WO 1 1 i am), Jr., 507 West Main Sto , Danville, Ky. 40422 Lohrer, Fred, Dept, of Zoology, Univ. of South Florida, Tampa, Fla. 33620 Longcore, Jerry R. , Section of Wetland Ecology, Patuxent Wildlife Research Center, Laurel, Mdo 20810 Lonnecker, W(illiam) M(eredith), 1310 Devil's Glen Rd. , Bettendorf, Iowa 52722 Lovejoy, Thomas E(ugene) Ml, Peabody Museum, Yale Uni Vo, New Haveny, Conn. 06520 Lovell, Mrs. C(harles) Edwin, 48 Christopher Dr., Box 5186, Poland, Ohio 44514 Lowden, F. Lee, Brooks Bird Sanctuary, Rt. 1, Box 97, Mill Run, Pa. 15464 Lowe, W. Ross, 96 McNaughton St., Sudbury, Ont., Canada * Lowery, George H(ines), Jr., Museum of Zoology, Louisana State Univ., University, La. 70803 Lowther, Peter E(dward), 309 Whitewood, Burlington, Iowa 52601 Luckenbach, Mrs. Bert A., 1548 Lehigh Parkway South, Allentown, Pa. 18103 * Ludwig, Frederick Edwin, 2864 Military St,, Port Huron, Mich. 48060 Ludwig, James Pinson, Dept, of Biology, Bemidj'i State College, Bemidj'i, Minn. 566OI Ludwig, John, Rt. 7, Chambersburg, Pa. 17201 Lueshen, Mrs. John, Wisner, Neb. 68791 Lukes, Roy J(oseph), Box 152, Bailey's Harbor, Wise. 54202 Lumsden, H. G. , Dept, of Lands & Forest, Southern Research Station, Rt. 2, Maple, Ont., Canada Lundgren, Randall W. , 3111 Burrmont Rd. , Rockford, 111. 61107 Lunk, William A., 865 N. Wagner Rd. , Ann Arbor, Mich. 48103 Luplent, Mary L. , Croixdale, Bayport, Minn. 55003 Luther, Mrs. Dorothy (Hobson), 4515 Marcy Lane, Apt, 239j Indianapolis, I nd, 46205 **Luwa^ Wm. R. , 309 State St., Mankato, Minn. 56001 * Lyman, Mrs. Clara Cross, Rt. 5, Wayzat©, Minn. 55391 Lynn, Robert T. , Biology Dept., Southwestern State Col lege, Weatherford, Okla. 73096 Lyons, Clifford R. , 6424 Mt. Adelbert Dr., San D i ego, Calif, 92111 Mabus, Mrs. Mildred M(axine), Rt. 1, Sesser, 111. 62884 i960 1958 1953 1925 1922 1946 1963 1966 1966 1960 1958 1969 1961 1937 1965 1956 1941 1962 1968 1952 1964 1961 1966 1937 1970 1935 1970 1944 1957 1969 1955 31a MacBriar, Wallace N. , Jr=, 2847 N. Stowell Ave., Milwaukee, Wise. 53211 MacFayden, Clifford J(ames), 159 Owen St., Barrie, Ont., Canada , Maclnnes, C. D. , Dept, of Zoology, Un i v. of Western Ontario, London, Ont., Canada Maciula, Stanley J. , 2 Springdale Court, Clifton, N. Jo 07013 Mack, Charles B. , Dept, of Biology, St. Joseph s College, Rensselaer, Ind. 4797° MacKay, Barry Kent, 35 Thornecliffe Park Dr., Apt. 1208, Toronto 17, Ont., Canada *"*Mackenz i e, Locke Litton, 829 Perk Ave. , New York, N. Y. 10021 * MacLean, John A,, Jr., 330 Locust Rd. , Winnetka, 111. 60093 * Macomb, J. de Navarre, Jr., 588 Arbor Vitae Rd. , Winnetka, 111. 60093 MacQueen, Peggy Muirhead, 71 Lake Link Circle, S. E. , Winter Haven, Fla. 33880 **MacRoberts, D. T., 550 Spring Lake Dr., Shreveport, La. 71106 MacRoberts, M. H. , Dept, of Zoology, Parks Road, Oxford, England Magner, J(ohn) Marshall, 516 Bacon Ave., Webster Groves, Mo. 63119 Mahan, Harold D., Biology Dept., Central Michigan Univ., Mt. Pleasant, Mich. 48858 Maher, William Joseph, Dept, of Biology, Univ. of Saskatchewan, Saskatoon, Sask. , Canada Mahlburg, Milton William, 1109 Grant Ave,, Rock- ford, 111. 61103 Malick, Donald L(eo), Box 728, Rt. 1, Evergreen, Colo. 80439 **Malloy, William F. , 6l6 Hatherly Rd., No. Scituate, Mass. 02060 Manners, Edward Robert, 108 North Monroe Ave., Wenonah, N. J. O809O Manning, T. H. , Rt, 4, Mer r i ckvi 1 1 e, Ont., Canada Mans, Marie L(ouise), 3713 Mt. Diablo Blvd., Apt. 33, Lafayette, Calif. 94549 Manuwal, David A., Dept, of Zoology, Univ. of California, Los Angeles, Calif. 90024 Manville, Richard H(yde), Fish & Wildlife Service, U. S. National Museum, Washington, D. C, 20560 March, James R. , 200 Kansas St., Horicon, Wise. 53032 * Mark, Cyrus, 80 Wentworth Ave., Glencoe, 111. 60022 * Mark, Mrs. Cyrus, 80 Wentworth Ave., Glencoe, 111. 60022 Marks, Jack Loran, 1107 S. W, 4th Ave., Portland, Ore, 97204 Marti, Carl D, , Dept, of Biology, Tarkio College, Tarkio, Mo. 64491 Martin, Dennis J(ohn), Biol, Dept, Univ, of New Mexico, Albuquerque, N. M. 87IO6 Martin, Donald F(rederick), Dept, of Biology, New Mexico State Univ., Las Cruces, N. M, 88OOI Martin, Elden W. , Dept, of Biology, Bowling Green State Univ., Bowl i ng Green, Ohio 43402 1968 1969 1959 1962 1968 1968 1947 1957 1967 1970 1969 1970 1948 1953 1951 1949 1958 1968 1942 1950 1962 1967 1941 1968 1960 1957 1949 1968 1970 1970 1963 32a Martin, Howard W. , Jr., 18 East Shore Blvd. , Willoughby, Ohio 44094 Martin, Joseph H, , 854 Cambridge Dr., S, E. Grand Rapids, Mich. 49506 Martin, M(urray) S(impson), 1413 Curtin St., State College, Pa. 16801 Martin, Stephen- G., Dept, of Zoology, Colorado State Univ., Fort Collins, Colo. 80521 Marvel, Carl S(hipp), 2332 E. 9th St., Tucson, Ariz. 85719 Marx, Edward J. F. , 115 Plymouth Place, Merchantvi 1 1 e, N. J. 08109 Marx, William B. , 213 Kent * Maslowski, Karl H(erbert), Cincinnati, Ohio 45230 Mason, C(harles) N(athan), N.W. , Washington, D. C. Place, Summit, N. J. 07901 1034 Maycliff Place, Sr. , 6432 31st St. , 20015 Mason, C. Russell, P. 0. Box 755, Altamonte Springs, Fla. 32701 Massie, Mrs. Joel, 1015 Locust St., #425, St. Louis, Mo. 63101 Mathisen, Mrs. John, 1001 Miles, Bemidji, Minn. 56601 Matray, Paul F(redricl<), Dept, of Forest Zoology, State University College of Forestry, Syracuse Univ., Syracuse, N. Y. 13210 Maxwell, George R. , II, Rice Creek Biological Field Station, State University College, Oswego, N.Y. 13126 Maxwell, Terry C. , 1025 Cactus Lane, San Angelo, Texas 769OI Mayer, Charles C(ushing) B(ailey), Elm Grove, Col rain. Mass. 01340 * Mayfield, Harold F(ord), River Road, R. D. , Water- vi 1 le, Ohio 43566 * Mayr, Ernst, Museum of Comparative Zoology at Harvard College, Cambridge, Mass. 02138 * Mazzeo, Rosario, Rt. 1, Box 213, Carmel, Calif. 93921 McAllister, Mrs. N. A., 2883 Otterson Dr., Ottawa 10, Ont., Canada McBee, Mrs. Lena G(riffin), Landsun Homes, Inc., 2002 Westridge Rd. , Carlsbed, N. M. 88220 McBride, Mrs. Bonnie Rose, P. 0. Box 669, Los Banos, Calif. 93635 * McCabe, Robert A(lbert), 424 University Farm Place, Madison, Wise. 53705 * McCamey, Franklin, 3854 Crawford Rd. , Dryden, Mich. 48428 , . McChesney, Donald S. , 207 Wynthrop Rd. (Solvay), Syracuse, N.Y. 13209 **McC1ure, H(owe) Elliott, Migratory Animal Patho- logic3l Survey^ APO San Francisco, Calif* 963 46 McCormick, John M. , 1827 Richards Rd. , Toledo, Ohio 43607 McCullough, C(lyde) Robert, North Cheshire St., Burton, Ohio 44021 McDiarmid, Mrs. Mercedes Foster, Dept, ot Zoology, Univ. of South Florida, Tampa, Fla. 33620 1968 1959 1967 1968 1949 1970 1970 1934 1947 1963 1966 1963 1968 1960 1968 1958 1940 1933 1947 1957 1957 1 966 1942 1963 1963 1942 1951 1953 1968 33a McDonald, Malcolm E. , Bear River Research Station, P. 0. Box k59) Brigham City, Utah 84304 McEntee, Mrs. Howard G. , 940 Fairfield Ave. , Ridgewood, N. J. 07450 McFarlane, Robert W(illiam), Dept, of Zoology, Univ. of Florida, Gainesville, Fla. 32601 * McGaw, Mrs. G. Hampton, 18 Beech St., Woodsville, N. H. 03785 McGee, Janet M(itchell), 1703 N. 43rd St., Lawton, Okla. 73501 * McGeen, Daniel S. , 707 Community National Bank Bldg., Pontiac, Mich. 48503 McHenry, Merril G. , Biology Dept., Greenville College, Greenville, 111. 62246 Mcllvain, John F(olwell), 519 East Penncrest Dr., Langhorne, Pa. 19047 McKinley, Daniel L(awson), Biology Bldg., State University of New York, 1400 Washington Ave., Albany, N. Y. 12203 McKinley, George G(ael), P, 0. Drawer B, Glasgow, Ky. 42141 McKinney, D. Frank, Minnesota Museum of Natural History, Univ. of Minnesota, Minneapolis, Minn. 55455 McKinney, Mrs. Walter A., 2509 South Boston Place, Tulsa, Okla. 74114 McKnight, Mrs. Daniel M. , Box 10, Cedar Crest, N.M. 87008 McKnight, Edwin T(hor), 5038 Park Place, Washington, D. C. 20016 McLean, David C(osten), 550 Wisteria Dr., Florence, S. C. 29501 McLean, E. Bruce, Dept, of Biology, John Carroll Uni Vo, Cleveland, Ohio 44118 McManus, William Reid, Memramcook, New Brunswick, Canada McNeil, Raymond P(aul) J(oseph), Dept, des Sciences Bio logiques, Universite de Montreal, Case postal 6128, Montreal, P. Q. , Canada McNicholl, Martin K(eli), 1281 Valour Rd., Winnipeg 3, Manitoba, Canada * Meade, Gordon M(ontgomery ), 72 West Glen Ave., Ridgewood, No J. 07450 Meanley, Brooke, Patuxent Wildlife Research Center, Laurel, Md. 20810 Mehner, John F. , Mary Baldwin College, Staunton, Vao 24401 Meigs, Jonathan, 575 Ridge Rd. , Hamden, Conn. 06517 Mel linger, E(nos) O(ren), Rt. 1, Tiger, Ga. 30576 * Melons, Theodora G(ardner), 2601 Sunset Blvd., Apto 3B, Minneapolis, Minn. 55416 Mendinhall, Mrs. Dorothy A., "Damsite", Rt. 2, Chestertown, Md. 21620 * Meng, Heinz, State University College, New Platz, N. Y. 12561 * Mengel, Robert M(orrow), Museum of Natural History, Univ. of Kansas, Lawrence, Kan. 66044 **Menninger, Phil Bo, 1930 Webster, Topeka, Kan. 66604 Meritt, James Kirkland, 809 Saratoga Terrace, Whit- man Square, Blackwood P. 0., N. J. 08012 Mers, William H(enry), 1659 Marlowe Ave., Cincinnati, Ohio 45224 1936 1948 1959 1945 1969 1944 1967 1962 1948 1945 1966 1945 1969 1936 1962 1970 1969 1 966 1968 1938 1950 1949 1969 1939 1947 1964 1943 1937 1949 1944 1949 34a 345 Boston Ave. , 344 S. E. S. E. , Bartles- Elmhurst, Bartlesville, Sc i ence. Mery, Mrs. Sophia C. , ville, Okla. 74003 Messerly, Mrs. John F. , Okla. 74003 * Metcalf, H(omer) N(oble), Dept, of Plant S- Soil Montana State Univ. , Bozeman, Mont. 59715 Metcalfe, Orrick, The Parsonage, Natchez, Miss. 39120 Mewaldt, L(eonard) R(ichard), Dept, of Biological Sciences, San Jose State College, San Jose, Calif. 95114 Meyer, Henry, Rt. 4, Box 64, Whitewater, Wise. 53190 Meyerriecks, Andrew J(oseph), Dept, of Zoology, Univ. of South Florida, Tampa, Fla. 33620 Meyers, Ernest G. , 6359 64th Ave., Apt. B-8, East Riverdale, Md. 20840 * Meyers, Kenneth Lewis, 5441 Far Hills Ave., Dayton, Ohio 45459 Michaud, Howard H(enry), 301 East Stadium Ave., West Layafette, Ind. 47906 Mickelson, Peter G. , Dept, of Wildlife & Fisheries, School of Natural Resources, Univ. of Michigan, Ann Harbor, Mich. 48104 Middleton, William R(obert), 109 South Jackson Ave. , Wenonah, N. J. 08090 * Mikkelson, Herbert G. , Box 142, Minnetonka Beach, Minn. 55344 P. 0. Box 673, Man i touwadge, Ont., M M M M * M ■k •k M M M * M Prairie Migratory Bird Research of Saskatchewan, Saskatoon, les, John B. , Canada ley, Theodore R., 18579 Edinborough, Detroit, Mich. 48219 liar, John B. , Center, Univ. Sask. , Canada 1 1 er, Aland., 07435 Mrs. A 33936 Clark, Inwood, Douglas Scott, Ont., Canada N. J. 1 1 er, Fla. 1 1 er, 1 1 er, 12, Rt ice. 4, 1 7 Vreeland Rd. , 802 Laredo Ave., Newfound land, Lehigh Acres, W. Va. 25428 368 Glengarry Ave., Toronto 2910 Laurel Dr. Sacramento, Creek Blvd., 1 ler, I itene E. , Calif. 95825 ller, Lyle (DeVerne), 5795 Mil Youngstown, Ohio 44512 ller, Robert R(aymond), 929 6th Ave., Bethlehem, Pa. 18018 . ller, Sheldon L(ee), Museum of Zoology, Univ. of Michigan, Ann Arbor, Mich. 48104 ller, Mrs. William C. , 4723 Shadywood Lane, Dal 1 as, Texas 75209 , , 11s, Michael H. , Dept, of Biology, Western Michigan Univ., Kalamazoo, Mich. 49001 _ nock, Michael E. , Dept, of Ecology & Behavioral Biology, Bell Museum of Natural History, Univ. of Minnesota, Minneapolis, Minn. 55455 not, John Granville, 244 Brattle, Cambridge, Mass. 02138 /• n • D skimen, Mildred, P. 0. Box I6, Put-in-Bay, Ohio 43456 r, 1 Dl tchell, Harold Dies, 238 W. Royal Pky., Wi 1 1 iamsvi 1 le, N. Y. 14221 1955 1968 1944 1968 1947 1939 1948 1969 1949 1938 1969 1953 1948 1958 1960 1956 1969 1944 1953 1939 1955 1947 1954 1969 1961 1969 1967 1957 1950 1936 35a Mitchell, Newell W. , 29 F Heritage Village, Southbury, Conn. 06488 I968 ■* Mitchell, Mrs. Osborne, 1420 Beach Drive, Apt. 701, Victoria, B. C. , Canada 1933 Mockford, Edward (Lee), Dept, of Biological Sciences, Illinois State Univ., Normal, III. 6I76I 1946 Mohr, William J., Box 87, Winesburg, Ohio 44690 I968 Monk, Harry C(rawford), No. 5 Westminister Apts., 2013 Capers Ave. , Nashville, Tenn. 37212 1920 * Monroe, Burt L(eavelle), Jr., Dept, of Biology, UniVo of Louisville, Louisville, Ky. 40208 1946 Monson, Gale, 5412 Inverchapel Rd. , Springfield, Va. 22151 1933 Montgomery, G(eorge) H(ugh), 4689 Westmount Ave., Westmount 6, P. Q. , Canada 1964 Montgomery, Mrs. G(eorge) H(ugh), 4689 Westmount Ave., Westmount 6, P. Q. , Canada 1964 Montgomery, James Braxtol, Jr., 780 W. Center, Fayetteville, Ark. 72701 1970 Montgomery, Robert A., 1208 So. Dundee, Dundee, 111. 1 966 Moody, Frank B. , 826 Spruce Ave., West Chester, Pa. 19380 1969 Moody, Marjorie J., 3030 Verde St., Apt. 7, Bakersfield, Calif. 93304 1957 Moore, Robert B(yron), 11926 Broken Bough, Houston, Texas 77024 1947 Morgan, Fred D. , 1032 Wildwood Dr., Huntington, Ind. 46750 1965 Morgan, Lee, 4 Windsor Lane, East Northport, N.Y. 11731 19^9 Moriarty, Lester J. , 920 3rd St., N. W. , Watertown, S. D. 57201 1957 Morman, Robert H. , 5943 W. Pleasant Ridge Dr., C-7, Ludington, Mich. 49431 1964 * Morrison, Kenneth Douglas, Mountain Lake Sanctuary, Lake Wales, Fla. 33853 1937 Morrison, Vaugh W. , Math Dept., Florida Presby- terian College, P. 0. Box I256O, St. Petersburg, Fla 33733 1968 Morrow, Mrs. Dessie Powers, 1320 N. State St., Chicago, 111. 6O6IO 1949 * Morse, Douglass H. , Dept, of Zoology, Univ. of Maryland, College Park, Md. 20742 1956 **Morse, Margarette Elthea, 122 West South St., Viroqua, Wise. 54665 1921 Mortensen, John W(flliam), 701 West 24th St., Upland, Calif. 91786 1970 Mortenson, F(redric) Joseph, Dept, of Psychology, Dalhousie Univ., Halifax, N. S. , Canada I968 Morton, Eugene Siller, Smithsonian Tropical Research Institute, Box 2072, Balboa, Canal Zone 1959 * Mudge, Edmund W. , Jr., 5926 Averill Way, Dallas, Texas 75225 1939 Mueller, Dennis R(alph), 7620 Mission Dr., Franklin, Wise. 53132 1966 ■**Mueller, Florence N, 4408 Pine St., Omaha, Neb. 68105 1951 Mueller, Helmut C(harles), Dept, of Zoology, Univ. of North Carolina, Chapel Hill, N. C. 27514 1949 Mueller, Wayne Paul, Dept, of Biology, Univ. of Evansville, Evansville, Ind. 47701 I968 36a * Muhlbach, W(alt) L(aurltz), 3102 Oregon St., Bakers- field, Cal if. 93306 Mumford, Russell E(ugene), Dept, of Forestry 6- 47907'*'^^^'°'^" Univ. , West Lafayette, I nd. Munyer, Edward A., 4324 N.W. 31st Terrace, Gaines- ville, Fla. 32601 Munzinger, J(ohn) Stephen, Dept, of Zoology & Ento- mology, 1735 Neil Ave., Columbus, Ohio 43210 * Murray, Bertram George, Jr., Dept, of Natural Sciences, Mich. State Univ., East Lansinq, Mich. 48823 Musselman, T(homas) E(dgar), 124 South 24th St., Quincy, 111, 62301 Myres, M(iles) T(imothy), Dept, of Biology, Univ. of Calgary, Calgary, Alberta, Canada Myrick, Horace S., I7IO 29th Street, Lubbock, Texas 7941 1 1951 1949 1963 1964 1954 1940 1964 1970 Nagel, Jerry W. , 1603 Chickees St., Johnson City, Tenn. 37601 Nagel, Lillian, 5616 Oleatha Ave., St. Louis, Mo. 63139 Nearing, C(harles) Turner, 1400 West Macon St., Decatur, 111. 62522 Nearing, Mrs. C(harles) Turner, 1400 West Macon St., Decatur, 111, 62522 Neel, Charles- A(ndrews), Star Rt., Box 187, Sheffield, Penna. 16347 Neff, Johnson Andrew, 3965 South Bannock St., Englewood, Colo. 80110 Neher, Harry T(ralnor), 5525 N. Maria Dr., Tucson, Ariz. 85704 Neill, Robert Lee, Biology Department, Univ. of Texas-at-Ar 1 I ngton, Arlington, Texas 76OIO * Nelson, Mrs. Carl R,, Jr., c/o Carl R. Nelson, Jr., School of Architecture, Univ. of Manitoba, Winnipeg, Canada * Nelson, Charles E(llsworth), Jr., Box I6l, Rt. 1, Dousman, Wise. 52118 * Nelson, Theodora, 315 East 68th St., New York, N. Y. 10021 Nero, Robert William 546 Coventry Rd. , Winnepeg 20, Manitoba, Canada * Netting, M(orris) Graham, Carnegie Museum, Pitts- burgh, Pa. 15213 Nevius, Mrs. Richard, Rt. 3, Greenvl 1 1 e, Tenn. 37743 New, John G., Dept, of Science, State University College, Oneonta, N. Y. 13820 **Newman, Donald L, , 14174 Superior Rd. , Cleveland Heights, Ohio 44118 Newman, George A(llen), Dept, of Biology, Hardin- Simmons Univ., Abilene, Texas 79601 Newman, Robert J(ames), 655 Ursuline Dr., Baton Rouge, La. 708O8 Nice, L(eonard) Bo, 5725 Harper Ave., Chicago, 111. 60637 * Nice, Mrs. Margaret Morse, 5725 Harper Ave., Chicago, 111. 60637 _ * Nickel 1, Walter Prine, Rt. 5, Box 127B, Clinton, Tenn. 37716 1970 1970 1962 1962 i960 1920 1958 1965 1959 1937 1928 1947 1941 1940 1946 1957 1969 1950 1932 1921 1943 37a Nlergarth, Grover G. , 26490 Drake, Farmington, Mich. 48024 }962 Nighswonger, Paul, 722 2nd St., Alva, Okla. 73717 19o8 Niles, David Mathesen, Museum of Natural History, Univ. of Kansas, Lawrence, Kan. 66044 1965 Niven, Kenneth Duncan, 61 Broadway, P. 0. Box 343, Monticel lo, N. Y. 12701 1967 Nolan, Val, Jr., Indiana Univ. School of Law, Bloomington, I nd. 47401 1940 Noland, Mrs. Hulbert V., 57 Indian Hills Trail, Louisville, Ky. 40207 1956 Nolf, Richard A., St. Joseph Museum, St. Joseph, Mo. 64501 1969 Norquist, Theodore C. , 5006 46th Ave. , N. E. , Seattle, Wash. 98105 1941 **Nork, Theodore J., 1711 W. Jarvis Ave., Chicago, 111. 60626 1947 Norman, James L(ee), 502 North 14th St., Muskogee, Okla. 74401 1948 Norman, Kenneth Duane, 3306 N. E. 141 st Ave., Portland, Ore. 97230 1957 North, Charles A., Biology Dept., Wisconsin State Univ. - Whitewater, Whitewater, Wise. 53190 1967 North, George W(ebster) 249 Charlton Ave., West, Hamilton, Ont., Canada 1941 * Novaes, Fernando C(osta), Museu Paraense Emilio Goeldi, Caix Postal 399j Belem, Para, Brasil 1953 Novy, Frank 0., 600 Somerset, Saginaw, Mich. 48603 1963 * Nowland, Paul J. , P. 0. Box 1409, Wilmington, Del. 19899 1950 Oberg, John C. , Rt. 1, Box 290A, Rockton, 111. 61072 1963 Odum, Eugene P(leasants), Dept, of Zoology, Univ. of Georgia, Athens, Ga. 30601 1930 Ogden, John C(lifton), 28991 S.W. I67th Ave., Home- stead, Fla. 33030 I960 * Ohlendorf, Harry M. , Dept, of Wildlife Science, Texas A S- M Univ., College Station, Texas 77843 1969 Oliver, Floyd C. , Lower Cape May Regional High School, Cape May, N. J. 08204 1968 Olsen, Humphrey A., Rt. 1, Box 419, Williamsburg, Ky. 40769 1964 Olson, James G., 3550 S.W., Woods St., Portland, Ore. 97221 I960 Olson, John B(ernard), 2438 West Skyline Pky., Duluth, Minn. 55806 1963 Olson, Storrs L. , Dept, of Pathob i ol ogy. School of Hygiene & Public Health, Johns Hopkins Univ., 615 N. Wolfe St., Baltimore, Md. 21205 I960 * O'Neill P(atton), Museum of Zoology, Louisiana State Univ., Baton Rouge, La. 70803 1962 * Oring, Lewis W. , Dept, of Biology, Univ. of North Dakota, Grank Forks, N. D. 58201 1962 Orr, John Hunter, 54 Duff Drive, Altoona, Pa. 16602 1968 Osborne, David R(oy), Dept, of Zoology & Physiology, Miami Univ., Oxford, Ohio 45056 1966 Otis, Robert E(dward), Psychology Dept., Michigan State Univ., E. Lansing, Mich. 48823 1970 Otteni, Lee Charles, Welder Wildlife Foundation, Box 1396, Sinton, Texas 78387 1970 38a Overing, Robert, Rt. 1, Chapin, S. C. 29036 Owen, J(ames) B(unyan), 2930 North Hills Blvd., Knoxville, Tenn. 3 7917 Owen, Ray B(ucklin), Jr., 91 Mill St., Orono, Maine 04473 Owre, Oscar T., Dept, of Zoology, Univ. of Miami Coral Gables, Fla. 33124 i 1930 I960 1 966 1935 Palmer, Ralph S(imon), New York State Museum, State Educational Bldg., Albany, N.Y. 12224 **Palmquist, Clarence O(scar), 834 Windsor Rd. , Glenview, 111. 60025 Pangborn, Mark W(hite), 25 E. 56th St., Indiana- polis, I nd. 46220 Parker, Geoffrey S(tephen), CMR, CCK Air Base, APO San Francisco 96319 Parker, William Edward, 200 South Main St., Hights- town, N. J. 08520 * Parkes, Kenneth Carroll, Carnegie Museum, Pittsburqh, Pa. 15213 Parks, Richard Anthony, 253 l4th St., N. E. , Apt. 12, Atlanta, Ga. 30309 Parmalee, Paul W(oodburn), Illinois State Museum, * Parmelee, David F(reelancl), Dept, of Biology, Kansas State Teachers College, Emporia, Kan. 668OI Parnell, James F. , Biology Dept., Wilmington College, Wilmington, N. C. 28401 Payne, Robert B(erkeley), Bird Division, Museum of Zoology, Univ. of Michigan, Ann Arbor, Mich. 48104 Paynter, Raymond A(ndrew), Jr., Museum of Comparative Zoology, Harvard Univ., Cambr i dge, Mass. 02138 Peabody, William C. , 1045 Grand, Emporia, Kan. 668OI PeaJ