HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology Tfie WIson Bulletin PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W. VA. VOL. 79, No. 1, MARCH 1967 PAGES Lt128 IVJJS. COIviP. -O'. library IvIAh 1 3 1967 In f-\ K V M I \ ij UNIVERSITY The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President — Aaron M. Bagg, Farm Street, Dover, Massachusetts. First Vice-President — H. Lewis Batts, Jr., Dept, of Biology, Kalamazoo College, Kalamazoo, Michigan. Second Vice-President — William W. H. Gunn, 455 Meadow Wood Road, Clarkson, Ontario. Secretary — Pershing B. Hofslund, Dept, of Biology, Duluth Branch, University of Minne- sota, Duluth, Minnesota. Treasurer — C. Chandler Ross, Academy of Natural Sciences, 19th and Parkway, Philadelphia, Pennsylvania. Elected Council Members — Stephen W. Eaton (term expires 1%7) ; Jeff Swinebroad (term expires 1968) ; Kenneth C. 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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 $5.00 per year, effective in 1965. Single copies, $1.25. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at $1.25 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 paid at Lawrence, Kansas, U.S.A. Allen Press Inc., Lawrence, Kansas THE WILSON BULLETIN A Quarterly Magazine of Ornithology George A. Hall Editor Editorial Advisory Board Tom J. Cade William C. Dilger William W. H. Gunn William A. Lunk Andrew J. Meyerreicks Robert W. Nero Kenneth C. Parkes Raymond A. Paynter, Jr, Ornithological Literature Editor Olin Sewall Pettingill, Jr. Volume 79 1967 Published by THE WILSON ORNITHOLOGICAL SOCIETY THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society Vol. 79, No. 1 March 1967 Pages 1- CONTENTS Variation in Central American Flickers Lester L. Short, Jr. The Double-scratch as a Taxonomic Character in the Holarctic Emberizinae C. I. O. Harrison Movements of Female Ruffed Grouse during the Mating Season Robert B. Brander Weights of Birds from Alabama and North Carolina Paul A. Stewart and Robert W. Skinner Foods of the Black-bellied Tree Duck in South Texas Eric G. Bolen and Billy J. Forsyth Wind Drift, Leading Lines, and Diurnal Migration Helmut C. Mueller and Daniel D. Berger The Contexts of Songs in Black-throated Green and Blackburnian Warblers Douglass H. Morse Damage by Golden-Fronted and Ladder-Backed Woodpeckers to Fence Posts and Utility Poles in South Texas John V . Dennis Agonistic Behavior in the American Goldfinch .... Ellen L. Coutlee General Notes CAVITY “excavation” BY CLIFF SWALLOWS Abbot S. Gaunt and Sandra L. Gaunt AN INSTANCE OF “W'llITE VVI NG-B AHKINc” IN THE COMMON CHOW Lester 7. Short, Jr. and Roxie G. Laybourne 128 5 22 28 37 43 50 64 75 89 no 113 COMPARATIVE FORAGING REIIAVIOR OF MYIOZETETES SIMILIS AND M, GHANA- DENSIS IN COSTA RICA Joel Cracraft 115 ATTACK BEHAVIOR OF A LOGGERHEAD SHRIKE Larry D. Caldwell 116 UNUSUAL BEHAVIOR OF THE YELLOW-HEADED BLACKBIRD Jerry R. LongCOre 117 AN AGGRESSIVE DISPLAY BY A TUFTED TITMOUSE Gary 0. Wallace 118 CAPE MAY WARBLER IN COSTA RICA Alexander F. Skutch 118 FEEDING REACTIONS OF MYRTLE WARBLERS TOWARD WAX-MOTH LARVAE DYED VARIOUS COLORS Janet S. Chappell and Robert W. Ficken 119 TONGUE DEFORMITY IN IMMATURE ROBIN Sally Hoyt Spofford 119 ABNORMAL TONGUE IN A ROBIN Ralph M. Edeburn 120 The President’s Page Aaron M. Bagg 121 Ornithological News 122 Ornithological Literature 123 Dean Amadon, Birds around the World: A Geographical Look at Evolution and Birds, reviewed by Harold Mayfield; Maurice Brooks, The Appalachians, reviewed by Ernest P. Edwards; A. W. Johnson, The Birds of Chile and Adjacent Regions of Argentina, Bolivia, and Peru, reviewed by Claes Chr. Olrog; Harold C. Hanson, The Giant Canada Goose, reviewed by Charles D. Macinnes; Arthur S. Einarsen, The Black Brant: Sea Goose of the Pacific Coast, reviewed by Karl W. Kenyon; Henry Hill Collins, Jr. and Ned R. Boyajian, Familiar Garden Birds of America, reviewed by W. J. Breckenridge. tViUi.. COMP, ZOOL, LIBRARY MA8 1 3 1967 hiMfX V ArviJ UNIVERSITY VARIATION IN CENTRAL AMERICAN FLICKERS Lester L. Short, Jr. \ W j HILE investigating hybridization and its effects on flicker populations, W I undertook a general study of variation in the two North and Middle American species, Colaptes auratus and C. (Nesoceleus) fernandinae. For reasons presented elsewhere (Short, 1965a) the five major groups of C. auratus, namely the auratus, cafer, chrysoides, chrysocaulosus, and mexi- canoides groups, are considered conspecific. (A vernacular name for this assemblage is difficult to arrive at; perhaps “Black-breasted Flicker” best describes and distinguishes C. auratus.) The present paper deals with varia- tion in the allopatric Central American mexicanoides subspecies group of Colaptes auratus. This group is currently comprised ( Peters, 1948) of the races mexicanoides and pinicolus, which are usually regarded (Peters, 1948; Blake, 1953; Eisenmann, 1955; Miller, et ah, 1957) as part of the “species” Colaptes cafer. I have elsewhere dealt with variation in the allopatric. West Indian chrysocaulosus subspecies group of C. auratus (Short, 19656), and variation in the mexicanoides group will be treated similarly. Mensural and plumage features of this widespread species of flicker are highly variable, and their plumage patterns lend themselves to study because they are com- posed of discrete elements such as bars, spots, and patches. MATERIALS AND METHODS The study of Central American flickers was hampered by lack of specimens from various areas within this region of diverse terrain and habitats. For the sake of comparison with other populations of flickers, attention was focused primarily on late winter, spring and early summer specimens, i.e., those taken roughly during the breeding season. Seasonal variation was considered, and specimens collected at other times of the year were also included in the analysis when no seasonal variation was noted. Only adult flickers are considered here, as variation in the juvenal plumage of Colaptes auratus will be discussed elsewhere. The total number of adult specimens from which data in the report were gathered is 160. These include 90 males and 70 females from Mexico (Chiapas), Guatemala, El Salvador, Honduras, and Nicaragua. Sample sizes were insufficient to make locality by locality comparisons. Available specimens were therefore grouped into five composite samples, although this procedure is admittedly less desirable. Figure 1 depicts locali- ties represented by specimens used in this study, and also shows the segrega- tion of composite samples. These will hereafter he designated the Chiapas. Guatemala, El Salvador, Honduras, and Nicaragua sam})les. 5 6 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 S c ° .t; 5 <3J c« £ '5->

r;:^ a; C £ £ > o o ^ ^ . o o — ” .5 o 3 3 bD > o .£ 'yT 3 3 ^0-3 ^ -2 c 3^3 1) Oi 5 o 2 3 O i 4^ 3 8 O O ; a K 2 I cfi > ■ ^ o > 3 1 O ' bC -3 J5 3 3 £ > 'i ^ < : S E ^ ) cT) ;:^ ' £ 3 > S S 1 ^ ^ tTj tfi .3 3 ^ O a .3; iH 3 'r o -3 ^ 3 G t3 o; uj c« .330 a =« o r- O I § O r, ’—^ 3 1/3.3 2 o ^ S 3 9 -3 "bi o a, S £ 2 — a o 3 If ~0 bt c o 3 3 O ^ § g O O o Lester L. Short, Jr. CENTRAL AMERICAN ELICKERS 7 The composite Nicaraguan sample was secured in the mountains of northern Nicaragua, with specimens principally from San Rafael del Norte (total Nicaraguan sample = 8 $, 5 $ $ ) . The Honduran sample mainly represents east-central Honduras, and includes moderate-sized samples from Subirana, Rancho Quemado, Cantoral, El Hatillo, and the vicinity of Tegucigalpa ( total sample = 25 ^ ^ , 20 $ $ ) . The El Salvador sample comes principally from Los Esesmiles, Department of Chalatenango (total sample — 1$ 5,6$ $ ) . This composite sample, representing the small highland area of El Salvador, includes the only flickers available from central Honduras to east-central Guatemala; it is effectively a “West Honduran” sample. The Guatemalan composite sample ( 33 5 5 , 33 $ $ ) is principally derived from central and west-central Guatemala, with the following major localities: Lake Atitlan area, Momostenango, Nebaj, and San Mateo. It also includes the eastern-most Chiapan locali- ties Comitan, 25 miles SE Comitan, and Volcan de Tacana. The Chiapas sample (7 5 5, 6 $ $ ) comes from three areas in the central Chiapas highlands ( Ocosingo, Pueblo Nuevo, San Cristobal de las Casas). The diversity within samples, particularly the Guatemalan sample, somewhat restricts comparisons. The statistics presented below for the composite samples reflect their variability, and are valid for the specimens being analyzed. Standard taxonomic procedures were used in the investigation. Measure- ments taken were: wing length (chord), tail length, bill length (from nostril, except as noted) and tarsal length. Data concerning some 30 quantitative and qualitative characters were utilized in this study. Information derived from study of some 5,000 specimens of flickers and their relatives (both sexes and all age groups) provided a broad basis for considering variation in Central American flickers. ECOLOGY AND BEHAVIOR Little is known of the ecology and behavior of the mexicanoides group of flickers. The birds occur primarily in open pine forest and pine-oak wood- land at various altitudes. Although generally found at elevations over 5,000 feet in Guatemala (Griscom, 1932; Land, 1962), they at least occasionally descend to much lower altitudes. Dickey and van Rossem ( 1938) reported flickers occurring in El Salvador down to 2,400 feet, and a female specimen in the American Museum of Natural History (No. 326633 1 was taken at 2,050 feet in Honduras. These flickers are similar to other North American flickers iCoIaptes auratus) in habits and behavior. They sufficiently resemble the cafer subspecies group that most workers (see citations above) consider them as part of Colaptes ^^cafer.’’’’ Dickey and van Rossem (1938:309) write of mexicanoides as follows: “There appears to be little or no difference, in the ecological niche occupied, between these El Salvador flickers and their northern congeners. In call notes, habits, choice of nesting sites, and appear- ance in life, they are scarcely, if at all, to be distinguished from Colaptes cajer.^’’ Wetmore (1941:547) found Guatemalan mexicanoides like “typical flickers in appearance,” hut considered their calls “quite different from the 8 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 CH I APAS 10 GUATEMALA I I EL SALVADOR 7 HONDURAS I 6 NICARAGUA 6 ALL 5 1 -■4^ N “10 N • I I N - 7 N “ 16 N = 7 N -53 165 WING LENGTH -1 1 I 160 155 150 BILL LENGTH -I 1 1 ^ ^ 1 I I I I I 145 140 M M 33 32 31 30 29 28 27 26 25 Fig. 2. Analysis of wing length and bill length in male Central American flickers. The dark vertical lines indicate the means, and the horizontal lines the ranges of variation in the samples. The white rectangle includes two standard errors around the mean, and each black rectangle includes one standard deviation on both sides of the mean. notes of the northern species.” Further observations of the behavior and ecology of Central American flickers, comprising the southernmost ( and an allopatric) population of Colaptes auratus, should be encouraged. CHARACTER ANALYSIS Wing Length Variation in wing length is considerable, individual variation being pronounced to the extent that female sample means are in several instances greater than those of males. The geographical variation is clinal, with northwestern birds (Chiapas) having wings averaging 9-12 millimeters longer than those of southeasternmost flickers (Nicaragua). The dine for males (Fig. 2) has its steepest gradient between Guatemala and El Salva- dor, while that for females is steepest from El Salvador to Honduras. The longest- winged male is from Chiapas and the shortest-winged male from Nicaragua; the female with the longest wings is from Guatemala and that with the shortest wings from Honduras. Nicaraguan and Honduran birds do not overlap Chiapas specimens in wing length, but do overlap measurements of Guatemalan birds. El Salvador flickers are intermediate between those from Honduras and Guatemala, and their variation is sufficient to overlap extreme samples from Nicaragua and Chiapas. Females have wings averaging but slightly shorter than those of males. Tail Length and Tail: Wing Ratios There is a general dine of decreasing tail length from northwest to southeast, with the tails of Chiapas birds averaging only 5-8 millimeters longer than those of Nicaraguan flickers (Fig. 3). The dine is less marked than that for wing length. El Salvador birds (both sexes) average closer to Chiapan flickers than do those from Guatemala. Despite the small size of the Nicaraguan samples, both male and female ranges overlap those of Lester L. Short, Jr. CENTRAL AMERICAN ELICKERS 9 CHIAPAS 0 _ 1 ' f GUATE MALA I -■rh-i -■li- 1 0 EL SALVADOR -i|:t 7 HONDURAS 1 0 NICARAGUA 6 ALL 43 TAIL LENGTH _i 1 1 i_ m\m TARSAL LENGTH i —1 1 1 1 1 1 120 115 no 105 MM 30 29 28 27 26 25 24 Fig. 3. Analysis of tail length and tarsal length in male Central American flickers. The dark vertical lines indicate the means, and the horizontal lines the ranges of varia- tion about the means. The white rectangle includes two standard errors around the mean, and each black rectangle includes one standard deviation on both sides of the mean. the Chiapas samples. The southeastern flickers tend to have proportionally longer tails than those from Chiapas and Guatemala, as the Honduran-Nicaraguan birds show tail length 4.5-6% and wing length about 7% shorter than those of Chiapan flickers. Fe- males’ tails average less than 1% shorter than those of males. Bill Length This feature is variable in flickers, and the Central American birds are no exception. The more southeastern flickers have slightly shorter bills, but the average difference in samples of both sexes is only a little over one millimeter (Fig. 2). The small Chiapan and Nicaraguan female samples are virtually alike in bill length. Particular attention was devoted to this character, for a chief characteristic of Dickey and van Rossem’s (1928) race pinicolus is its shorter bill. Their measurements of the culmen from its base (op. cit., p. 131) are: pinicolus — 7 5 (5 (El Salvador) — 38.9-41.6 mm, mean 40.1 mm mexicanoides — 4 $ $ (Chiapas) — 42.4-44.6 mm, mean 44.0 mm I obtained the following measurements of the culmen (from the base): Chiapas — 6 $ $ — 41.7-43.3 mm, mean = 42.73 mm Guatemala — 6 $ $ — 42.8-44.4 mm, mean =: 43.35 mm El Salvador — 5 $ $ — 38.8-41.9 mm, mean = 40.78 mm Honduras — 7 $ $ -39.4-42.5 mm, mean = 41.31 mm Nicaragua — 7 $ $ — 38.6-43.4 mm, mean z= 40.63 mm El Salvador birds, from data for both kinds of measurements, do indeed appear to have shorter bills than those from Guatemala and Chiapas. However, the sample from El Salvador is small, and flickers from farther southeast are variable enough to overlap considerably with northwestern birds. In fact, the Nicaraguan sample for the bill length 10 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 from nostril measurement (Fig. 2 for males; females also show this) and for culmen length from the base of the bill, completely overlaps measurements of the Chiapan birds. Considering the great variability of hill length in flickers, the difference between El Salvador and Guatemalan-Chiapan flickers is minor. Individual variation dependent upon psychological and or food availability factors results in variation in hill wear. An example of such effects is shown by comparison of two flickers for various hill measurements: Specimen a. bill length (from nostril) b. bill length (exposed culmen) c. bill length (culmen from base) c. minus a $ Univ. Calif. 30.8 mm 37.7 mm 41.9 mm 11.1 mm Los Angeles 18375 (El Salvador) 3 L^niv. Calif. Mus. 28.8 mm 37.0 mm 43.3 mm 14.5 mm Vert. Zool. 115400 ( Chiapas) Thus, the “shorter billed” Chiapas flicker ( taken April 7 ) has a much longer bill base and a worn bill, while the “longer-billed” El Salvador bird (taken Eebruary 19) ex- hibits a shorter bill base and longer bill tip. Because of the effects of wear, minor bill length differences are hence rendered unsatisfactory for defining populations of flickers. Bills of females average 3-4% shorter than those of males. Tarsal Length and Ratios Considerable individual variation in tarsal length was evident, and means for the Chiapan to Honduran samples are within a millimeter or so of each other (Eig. 3) with great overlap. Despite a significant difference between Honduran and Nicaraguan samples, overlap of both with other samples lessens its importance. Tarsal length thus shows no apparent geographic variation in the northwestern four samples, but appears to diminish between Honduras and Nicaragua. The tarsi of females average 1-2% shorter than those of males. Due to the greater variation in bill length, and considerable variation in tarsal length, ratios of tarsal length : bill length are highly variable. The total range for 110 adults is 0.79-1.08, the same as the range for the single Guatemalan sample. Wing Shape and Length of 10th Primary The non-migratory Central American flickers have relatively shorter, more rounded wings than their relatives to the north, including C. a. mexicanus. In fact, their wings are shaped very like those of the chrysocaulosus subspecies group (also non-migratory) of the West Indies (Short, 1965Z>). The more rounded shape of the wings in mexicanoides is caused by its generally short central primaries (P5-P81, and its fairly long outer ( P9, PIO) and inner (P1-P4) primaries. The fourth primary is almost as long as P8 in this form, not considerably shorter as in more northern races of C. auratus. The third primary is considerably longer than P9, P2 is as long as or ( usually ) longer than P9, and PI may be as long as P9. The tenth primary is closely similar in length among individuals of the various samples. El Salvador and Honduran birds have this primary the same size or longer than those of Guatemalan and Chiapan birds, while the tenth primaries of Nicaraguan flickers are Lester L. Short, Jr. CENTRAL AMERICAN ELICKERS 11 barely shorter. Mean PlO lengths and sample sizes are as follows (measurements in millimeters) : Chiapas Guatemala El Salvador Honduras Nicaragua 41.80 (5) 40.56 (9) 42.60 (5) 41.33 (9) 39.14 (7) 9 - 39.11 (18) 42.60 (5) 40.38 (8) 39.60 (5) Lack of a dine in PlO length renders this primary proportionally longer in the shorter- winged southeastern populations. Mean measurements of the ninth primary follow ( these measurements are taken from the tip of the feather to the skin around the base of the feather) : Chiapas Guatemala El Salvador Honduras Nicaragua $ 96.60 (5) 93.83 (6) 95.60 (5) 90.63 (8) 90.14 (7) $ - 94.07 (14) 96.3 (4) 88.63 (8) 90.40 (5) Birds from El Salvador have longer ninth primaries, like Chiapan and Guatemalan birds. However, the longer tenth primary in El Salvador flickers renders that sample more like birds from Honduras than those from Nicaragua in the PlO : P9 ratio. A “t” test of the differenee in the length of P9 between Guatemalan-Chiapan and Honduran- Nicaraguan flickers gave “f” values indicating a highly significant difference (P = 0.001 or less) for both sexes. Breast Spotting As noted by Lafresnaye (1844) in describing mexicanoides, this form has more trans- verse, bar-like spots than northern flickers. Only one of 91 adults had spots deeper than broad. Depth and width of a “normal” central breast spot were measured in each specimen. Averages for the five samples ranged as follows: Range of average breast Range of average breast spot depth spot width $ S — 3. 7-4.3 mm 5.4— 6.1 mm $ $ — 3.7-4.4 mm 5.4-7.5 mm Chiapan flickers have rounder spots than those of the other samples (mean difference between spot depth and spot width = 1.37 mm in 15 Chiapan adults, and 2.15 mm for 79 adults from southern Chiapas to Nicaragua). Females tend to have broader spots than do males. More breast spots are visible per unit area in mexicanoides than any other subspecies group except chrysocaulosus. The strong tendency toward barring in this form is also indicated by the fact that the lower abdomen was barred in all hut two of 77 adults checked for this feature. The other two birds showed chordate bars, and none exhibited spots. As in other flickers the females tend to he more strongly barred than males. Breast Patch Like the chrysoides and chrysocaulosus subspecies groups, mexicanoides has a deep round, rather than narrow, crescentic breast patch. The depth of the patch is variable, and the northwestern samples ( Chiapas-Guatemala) in particular show very deep breast patches. A statistical treatment of the data is presented in Figure 4 ( males only ) . The difference between the northwestern two and southeastern three samples is considerable, of the order of 12-18%, compared with only a 6-7% wing length difference between the extreme samples. Besides this geographic variation, mexicanoides exhibits a rather considerable sexual difference in breast patch deptb. 12 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 CH I A PAS 17 GUAT EMALA 26 EL SALVADOR 7 HONDURAS 20 NICARAGUA 8 ALL 86 I I ^ I I M M 30 25 20 15 10 Fig. 4. Analysis of breast patch depth in male Central American flickers. The measurement is of the maximum depth of the breast patch. Vertical lines denote means, horizontal lines indicate the ranges of variation within the samples. Each white rec- tangle includes two standard errors around the mean, and each black rectangle includes one standard deviation on both sides of the mean. Malar Patch The male malar patch in mexicanoides is variable in color, from red mixed with con- siderable black, to red. An anterior area before the red-black portion is colored cinnamon- rufous, and averages 11% (sample means 9-13%) of the total malar region. Utilizing malar color scores fully described elsewhere (Short, l%5a), the specimens were as- signed scores of “2”-“4” (briefly, “2” = 25-75% red, rest black; “3” = about 1-24% black; and “4” =: all red). Considerable individual variation was encountered, es- pecially in the northwestern samples. The following scores were attained by 87 males: “2” =:: 12, “3” = 73, “4” = 2. Females generally have cinnamon-rufous malar patches, with black or red visible on the surface in 18 of 39 adults (46%). Shafts of the females’ malar feathers are black at their bases. Gray color is lacking in malars of 79% (29 of 39) of the females, and when present is found only in traces ( up to 15% of malar area in one Honduran fe- male). Eight of the ten birds showing gray color are from the southeastern three samples. Only one of 36 males showed gray color amid the cinnamon in the anterior part of its malar patch, and that male is from Honduras. The southeastern flickers thus show less black in the male malar patches and more gray traces in those of females. Back Barring Perhaps the most striking feature of mexicanoides is its much broader back barring. Statistical treatment of data for back bar depth of all adults follows: N X ± 2 SE SD Range Coeff. Var. $ $ 88 3.65 ± 0.10 mm 0.45 mm 2.3-4.8 mm 12.33% $ $ 68 3.65 ± 0.10 mm 0.41 mm 2.6-4.6 mm 11.23% There is no sexual difference in mexicanoides, though females of other subspecies groups of Colaptes auratus have broader bars than males. Back bar depth is much greater than Lester L. Short, Jr. CENTRAL AMERICAN FLICKERS 13 in all other forms of C. auratus, including the chrysocaulosus group. There is no appar- ent geographic variation in this character. Test (1940) showed that mexicanoides has broader dark back bars than other North American flickers, and pointed out that the light brown interspaces between the dark back bars of mexicanoides are of the same width or narrower than the dark bars (in contrast to the situation in other forms of Colaptes auratus, which have interspaces always broader than the bars). He also noted that the interspaces are often two shades of brown, being duskier near the black bars and more cinnamon-rufous away from them. This imparts a tri-colored effect to the back color, an effect not noted in other North American flickers. Bars on the upper wing coverts of mexicanoides are also broader than in other North American flickers. The number of dark bars on the back feathers is also greater in mexicanoides. The number of complete and incomplete (bars noted as %, Vj, % complete or incomplete) bars was counted on an upper back feather of 76 adults. No sexual difference was evident, the male mean being 2.51 and that for the females 2.46 (means for more northern flickers vary between 1.4 and 2.1). Sample means clustered around 2.5, and no geographic variation was noted. The dark bar at the tip of each back feather was not counted. These bars are small, but of sufficient depth so that some breeding birds with worn feathers still possess them (in contrast, flickers from farther north have narrower black tips, nearly always worn off by the breeding season). Back Color The backs of these flickers are rich, cinnamon brown to rufous brown, marked with dark bars which are often (especially in southeastern populations) buff-bordered. Chiapan birds average darker than the others, and show less variability. Guatemalan flickers are highly variable, and exhibit the light and dark extremes of mexicanoides. Samples from El Salvador, Honduras, and Nicaragua contain mostly lighter colored birds, but a few Honduran individuals match the darkest Chiapan flickers. Females do not differ from males in back color. Seasonal variation is considerable, the back color being much darker in fall birds than in those taken during the breeding season. Rump Markings North American flickers generally exhibit a white rump patch. This patch is, however, partly obscured by spots or bars in occasional individuals of the auratus, cafer, and chrysoides subspecies groups, while the chrysocaulosus and mexicanoides groups gen- erally have spotted and/or barred rumps. Scores were assigned as follows: Score Condition of rump markings 0 White, no markings 1 1-6 spots or bars 2 More than 6 bars or spots, but rump largely white 3 Many markings, but one or several areas of white with no marks 4 Barred and/or spotted throughout Central American flickers generally have rump patches scoring “2” or “3,” but scores range from “1” to “4.” Females consistently show higher scores, as in all populations of Colaptes auratus. Geographic variation is slight, and principally involves reduction of markings in the southeastern populations. Nicaraguan flickers especially exhil)it less barring or spotting in their rumps, and seven of the ten individuals scoring “1” come from Nicaragua and Honduras. The lowest number of marks found was two, in a Nicaraguan flicker. The average score for all Central American males was 2.63 (.V=: 14 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 87, SE = 0.03, sd=z0.84), and for all females 2.92 (.^'^ = 68, se z= 0.11, so = 0.87). These compare with scores of 3.48-3.95 for samples of Cuban and Grand Cayman popu- lations representing the chrysocaulosus group. Part of this difference is due to the rather smaller markings in mexicanoides compared with chrysocaulosus, but the latter obviously has a more heavily marked rump (only 19% of all mexicanoides score “4,” while 84% of chrysocaulosus do so). Higher scoring individuals tend to have more barring and less spotting on their rumps. About half the specimens of mexicanoides examined showed markings predominantly bar-like, while the others exhibited spots only. Upper Tail Covert Pattern Variation in upper tail covert pattern in Colaptes auratus has been figured by Chap- man (1891) and Short (19656). Although considerable variation exists in the cajer and auratus subspecies groups, there is less variation in the chrysoides, chrysocaulosus, and mexicanoides groups. The patterns exhibited have been categorized as all black, V- striped, horseshoe-tipped, and barred ( 20 examples of these patterns are figured in Short, 19656). The patterns grade into each other, and innumerable intermediate condi- tions are possible. Altbough many individuals of the northern populations (auratus and cater subspecies groups) show black, V-striped, and horseshoe-tipped patterns, these are uncommon and barred patterns nearly universal in the other subspecies groups. Con- sidering only the large, central upper tail coverts and their patterns in mexicanoides, 93% of the 115 individuals examined for this feature showed various barred patterns, and fully 67% exhibited a single pattern (simple, barred pattern). Six additional barred patterns were noted, while five different horseshoe-tipped, six V-striped, and one all black patterns were also observed. Although enough patterns were evident to indicate that mexicanoides has the potential for development of all major types, the number of individuals actually showing patterns other than of the barred type was small. Only four individuals showed no trace of the barred type of pattern. Nine birds exhibited two pat- terns of the same or different types, either by having the central coverts bi-patterned (feathers with one pattern basally, and another distally), or by showing asymmetry (one covert with one pattern, the other with another pattern). No geographical variation was noted, nor was there an indication of a sexual difference in patterns in these flickers. Amount of Black in Tail The extent of the black color at the tip of the tail was determined by use of three measurements: 1) the length of the black area from the tail tip toward the tail base; 2) the length of the black area on one central rectrix from its tip toward its base; and, 3) the extent of black along the shaft of the outer rectrix (rectrix 5) from its tip toward its base. Mean values for these in males are: 1) total extent — 39.29 mm, 2) R1 — 43.12 mm, and, 3) R5 — 9.87 mm. There is considerable individual variation, but geographic variation is not marked. The latter is suggested by the data, and confirmed by statistical treatment of data for black in the outer rectrix ( the measurement showing greatest variation among the five samples). Applying an analysis of variance test to the data from the four largest samples (all but El Salvador), an F value of 3.09 was attained, yielding P — 0.05-0.10. The difference is not highly significant, for the chances are one in ten to one in 20 that all four samples are drawn from the same population. Com- parable results were obtained from data for females which showed about 2% less black than males. Since this is nearly equivalent to the size difference between the sexes, there appears to be no sexual difference in tbe extent of black in the tails of these flickers. Lester L. Short, Jr. CENTRAL AMERICAN FLICKERS 15 Tail Barring Barring in the tail of mexicanoides tends to be less prominent than in more northern populations of Colaptes auratus, and much less than in the chrysocaulosus group (Short, 19656). An exception is the inner (central) rectrix, which is as heavily barred as in chrysocaulosus, and more strongly barred than in the other groups. Thus, rectrix one has an average of 3-5 bars in mexicanoides (mean 4.10 for 42 males and 4.53 for 43 females from all samples), compared with 4-5 bars in chrysocaulosus and (usually) 1-2 bars in populations of the other groups. The outer rectrices, however, average 2.25 bars in 71 male mexicanoides, and 3.04 in 51 females (compared with 7-8 bars in chrysocaulosus and 3-5 bars in the auratus and cafer groups). Females tend to be more barred than males, both on rectrix 1 and 5. Rectrices 2-4 are unbarred, or with the barest traces of a bar on number 2. No geographic variation was evident in this character. Nuchal Patch The auratus and chrysocaulosus subspecies groups possess a red nuchal patch gen- erally lacking in the other groups. Some individuals of the mexicanoides group show a partial nuchal patch, and Test (1940) noted the presence of a patch in three of 31 mexicanoides he examined. Individuals were scored for the nuchal patch character as previously described (Short, 1965«). Briefly, a full nuchal patch is scored “0,” a restricted, but unbroken one — “1,” a broken patch with several areas of red — “2,” a trace or traces of red in one or several feathers — “3,” and the nuchal patch entirely absent — “4.” All 64 females examined lacked red in the nuchal area, thus scoring “4.” One-quarter of the males (20 of 80) showed some indication of red nuchal coloring, with four individuals scoring “2” and 16 scoring “3.” The mean score for all males was 3.71 (se = 0.06). As might be expected with a feature found in only a small part of the population, sample sizes are not adequate to demonstrate geographic variation, or the lack of it, in the nuchal patch character for males. The number of males scoring “2” and “3” in each sample is as follows: Chiapas — 6/17, Guatemala — 3/27, El Salvador — 2/7, Honduras — 5/21, and Nicaragua — 4/8. Throat Color The throat of mexicanoides is gray, about as in the cafer group, but slightly darker. Signs of brown or tan color were observed on the throats of 25 of 112 adults taken from late winter to early summer. This approach to the mixed tan and gray throats of most juvenile flickers was not noted in the other subspecies groups. More females than males showed tan or brown coloring (17 of 55 females, 8 of 57 males — a Cbi-square test shows this difference to be significant at the P = 0.01 level), and the only two individuals showing nearly as much brown and tan as gray were females. Tbe tendency for brown or tan color to develop appears more pronounced in the southeastern populations. All eight males showing such color came from the southeastern three samples, while 12 of the 17 females do so. All four Nicaraguan females show brown or tan coloring, and two of these are the birds with the most extensive development of these colors. Chiapan and Guatemalan samples include no males and but five females with such tan or brown coloring. It is likely that the mixed colors of the throats of these southernmost flickers, and those of juvenile birds as well, reflect a past condition when both gray and tan colors had developed, but before stabilization of one or tbe other had taken place. Fall birds show still more brown and tan present. Seasonal variation involves wear and fading, causing tbe throat to become grayer through tlu* fall, winter, and spring. 16 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Color of Ear Coverts The ear covert area includes the auricular feathers and feathers of the subocular region (forward to the bill). This entire area is generally colored like the throat in all forms of Colaptes auratus, and is thus gray in mexicanoides. Apparently genetic control of the coloring of this area is relatively independent of that involved with throat color, as indicated by studies of hybridization (Short, 1965aK Although tan color is present in the otherwise gray ear coverts of some mexicanoides, it never approaches comprising 50% of the ear-covert area. Unlike the case of throat color, more males than females (17 of 80 ^ 5 , 10 of 63 $ $ ) show tan or brown color, although the difference is not significant. Geographical variation is not evident, for Honduran and Chiapan samples contain greater numbers of individuals with tan or brown traces, while only one Nicaraguan (of 12), two Salvadoran (of 13), and eight Guatemalan (of 55) individuals exhibit such traces. Southeastern samples thus contain proportionally as many birds with brown and tan traces as do the northwestern samples. Color of Under Wings and Tail ( — “Shaft” Color) Shaft color in mexicanoides varies from orange to (rarely) salmon-pink. As in other populations of C. auratus, there is no sexual difference in this character. Shaft color was scored as in studies of hybridization in flickers (Short, l%5a). The scores attained were “3,” “3.5,” and “4.” A score of “4” denotes the salmon-pink color normally found in the cafer subspecies group. A score of “3” indicates orange shaft color, as found in some hybrids between the auratus and cafer subspecies groups. The intermediate orange- salmon color was scored “3.5.” The mean score for 159 adults taken from late winter to summer was “3.26,” with two standard errors = 0.06 and one standard deviation = 0.37. Means for the two sexes considered separately were: $ $ (90) =r “3.29,” $ 9 (69) =i “3.26.” Four birds showed yellowish in certain feathers. Three of these have very pale shaft color overall, and one (Mus. Comp. Zool. No. 121036) has yellowish-orange in rec- trices 3-5 on the right side, while the same feathers are orange-pink on the left side. This yellow tendency is probably related to dietary factors and effects of fading as discusssed elsewhere (Short, 1965a). No individual of mexicanoides exhibited a sym- metrical pattern of bright yellow-orange shaft color in one, several or all remiges and rectrices, as typically found in hybrids between the auratus and cafer groups. Mean shaft color scores ranged from “3.06” for Honduras to “3.46” for Nicaragua. No clinal varia- tion is evident, but Honduran flickers seem to be more uniformly orange-shafted than those from elsewhere. In the other four samples, from 40 to 70% of the individuals scored “3.5” and “4,” and, overall, 50% (51 of 102) of the birds in all four samples exhibited such scores. However, only 7% (3 of 41) of Honduran birds scored “3.5” or “4.” The Honduran sample is thus significantly different in this respect from the others, including the Nicaraguan sample ( in which nine of 13 birds scored “3.5” or “4”) . The meaning of this difference in unclear. Crown Color There is some variation in crown color in mexicanoides, with southeastern birds tend- ing to have paler, more cinnamon-rufous crowns and northwestern flickers exhibiting more rufous-chestnut coloring. There is overlap even between individuals of the ex- treme (Nicaraguan and Chiapan) samples. Variation in color of the crown with respect to hybridization between the cafer and auratus subspecies groups has been discussed elsewhere (Short, 1965a). There is no evidence of gray traces in the crowns of speci- mens of mexicanoides', all thus score “4” (typical non-gray, usually brown, crown of Lester L. Short, Jr. CENTRAL AMERICAN FLICKERS 17 cafer subspecies group). However, mexicanoides has a rufous, rather than the brown, crown of the cafer group (an approach toward mexicanoides is evident in some mexicanus individuals, and in rufipileus of the cafer subspecies group, as well as in all races, es- pecially tenebrosus, of the chrysoides group). Traces of red coloring were evident in the crowns of four Honduran, one Chiapan, and one El Salvador males (traces in six of 48 males, or 13% of all males). Test (1940) reported red in the crowns of three of 17 mexicanoides males. The red, when present, appears primarily in the lores and sec- ondarily in the feathers of the forehead. The crown feathers become lighter in color over the course of the year, following the annual molt. There are no apparent sexual differences in this feature. Character Index Analysis In order that all forms of Colaptes auratus be treated in a standard man- ner for comparison of character (or hybrid) index values, the same scoring system utilized in the study of hybridization between the cafer and auratus subspecies groups (Short, 1965a) was applied to mexicanoides. The six index characters are: crown color, throat color, ear covert color, extent of nuchal patch, malar color (males ) and shaft color. Scores for each character ranged from “0” for the extreme auratus group condition, to “4” for the condition found in the cafer subspecies group ( races collaris, cafer) . Possible character index values thus range in males (six characters) from 0 for an individual registering the auratus condition in all characters to 24 for a bird having a ca/er-like condition of each character. The corresponding values for females (five characters) range from 0 to 20. Character index values ranged from 19-23 in 87 males of mexicanoides and from 17-20 in 63 females. The means with two standard errors are: males — 21.46 ± 0.20, and females — 18.79 ± 0.18. Of course, variation in index values is dependent upon variation in the separate characters making up the index. Thus, males vary considerably due to variation in nuchal, malar, and shaft color. Females exhibit less variation in index values because they lack one feature variable in males (malar character), and because they show no nuchal variation. Crown color is non-variable in both sexes, as far as hybrid index scoring is concerned (crown color varies in other ways, as noted above). Crown color of mexicanoides is assigned a score of “4,” as in the cafer group, because the rufous-chestnut color exhibited is closer to the browns of that group than to the grays of the auratus group. Sample means varied from 21.22 to 21.81 for males, and from 18.25 to 18.94 for females. In terms of those characters important in describing effects of hybridization between the cafer and auratus groups, mexicanoides indexes near the former. DISCUSSION The variation encountered within the mexicanoides group of populations, as indicated by available specimens, is largely clinal. For most characters 18 THE WILSON BULLETIN March 1967 Vol. 79. No. 1 major clinal "steps'* are not evident. The El Salvador sample, representing the area intermediate between the extreme Chiapan and Nicaraguan popula- tions. is variously intermediate between them in most features. In some characters, such as tail length. PlO : P9 ratio and breast spotting, the El Salvador sample is closest to the adjacent Guatemalan birds, while in others ( e.g.. depth of breast patch and bill length i it is closer to those from Hon- duras. Nicaraguan flickers are not represented by an adequate sample, but certainly appear to differ in average features from birds farther to the north. If no flickers occurred in the intervening area between Chiapas and Nicaragua, the differences between birds in these extreme regions would merit separate subspecific treatment for them. However, these extreme popu- lations are connected by intermediate populations. Furthermore, for most features, variants in the Guatemalan, and even the Chiapan samples, overlap with one or more birds in the small Nicaraguan sample.* This fact, plus the clinal nature of variation for many characters, and the considerable variation encompassed within each of the larger samples (Honduras, Guatemala I . militate against subspecific recognition of the Nicaraguan population. Dickev and van Rossem (1928) described the race pinicoliis from El Salvador. Those authors were unable to appreciate the variation and dines in mexicanoides, for they saw no Nicaraguan and Honduran specimens ( op. cit.. p. 131). As noted above, the El Salvador population is variously inter- mediate between those of Honduras and Guatemala l and hence between Nicaraguan and Chiapan populations), and this intermediate population does not merit a trinomial name. Stone (1932:316) was unable to distinguish pinicoliis from mexicanoides and I follow Stone in considering pinicolus a synonym of mexicanoides. The subspecies group mexicanoides is thus com- prised of the single subspecies mexicanoides. The diagnostic features of this subspecies group are: 1) wings more rounded than in other subspecies groups (except chrysocaulosus group) 2) breast markings generally broad, bar-like 3> breast patch deeper, less crescentic tas in chrysocaulosus and chrysoides subspecies groups) 4) malar patch mixed red and black in males and cinnamon-rufous in females 5) back bars deeper, more numerous than in other groups of Colaptes auratus (similar to pattern found in the South American flicker subgenus Soroplex) 6) back tends to be tricolored < buff, brown, and black), especially in the southeastern populations 7) rump patch moderately obscured by spots and/or bars, nearly to the extent found in the chrysocaulosus group * Additional 11?9) Nicaraguan specimens recently examined in the British Museum enhance this overlap. Lester L. Short, Jr. CENTRAL AMERICAN ELICKERS 19 8) “shaft” color generally orange to orange-salmon, less pink than in the cafer sub- species group 9) crown deep rufous-chestnut in color, approached but not attained by certain popu- lations of the cafer group Characteristics of the subspecies mexicaiwides are those of the mexicanoides subspecies group. The Central American flickers, although distinctive, show certain color pattern resemblances to the cafer and chrysoides subspecies groups. These include: 1) all have a basically “brown” crown 2) all have a gray throat 3) all have a predominantly red malar patch in males Additionally, mexicanoides shares with the cafer group the generally reddish color of the “shafts.” In certain respects noted above, mexicanoides resembles the chrysoides and chrysocaulosus groups more than it does the cafer group. In still other features it shows resemblances to the chrysocaulosus group, but not to the cafer and chrysoides groups. Mexicanoides is least similar to the auratus group. The significance of these resemblances and differences in terms of the past history of flickers will be discussed elsewhere. It is appar- ent, however, that the distinctive features of the mexicanoides group preclude the inclusion of the subspecies mexicanoides in the subspecies group cafer, with which it is generally associated. The subspecies of the cafer group {cafer, collaris, nanus, mexicanus, and rufipileus) generally exhibit clinal variation, and not even the well-differentiated race rufipileus approaches the level of morphological distinctiveness evident in mexicanoides. The Central American flickers show the effects of long isolation from other North Ameri- can flickers. While mexicanoides appears not to have differentiated to the species level, its features warrant its equal status within Colaptes auratus as a subspecies group along with the auratus, chrysocaulosus, cafer, and chrysoides subspecies groups. SUMMARY The North American flicker, Colaptes auratus, is represented in Central America by a population exhibiting distinctive morphological features. Variation within the Central American population, occupying the highlands of Chiapas, Guatemala, El Salvador, Honduras, and northern Nicaragua, is mainly clinal. Clines for the various characters appear to he concordant, from northwest to southeast; however, the number of specimens available was inadequate to show variation, or lack of it within major areas with diverse topography, such as Honduras. The northwestern birds (Chiapas) tend to he larger, darker, and less barred below than those from the southeastern populations. The clinal nature of the variation, overlap among individuals of the extreme populations, and intra- sample variation do not permit recognition of a second subspecies in the mexicanoides group of flickers. The race pinicohis Dickey and van Kossem is held invalid, for the 20 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 El Salvador population is intermediate between those of Chiapas and Nicaragua. Characteristics of the mexicanoides subspecies groups of Colaptes auratus are pre- sented. This group shows similarities with each of these subspecies groups: chryso- caulosus, cafer, and chrysoides. It differs in a number of important ways from the cafer group, and merits equal status with the four other subspecies groups iauratus, cafer, chrysocaidosus, and chrysoides) of C. auratus. ACKNOWLEDGMENT The opportunity to continue my investigations of flickers, including the present one, was provided by a fellowship award from the Chapman Memorial Fund Committee of the American Museum of Natural History, where much of the work was done. Drs. Dean Amadon and Wesley E. Lanyon and the staff of the museum were most helpful. Dr. Charles G. Sibley provided assistance and encouragement during early phases of my flicker investigations. The Karl P. Schmidt Committee of the Chicago Natural History Museum in 1961 gave me a travel grant, and the Louis Agassiz Fuertes Research Grant Committee of the Wilson Ornithological Society in 1956 provided me with a Fuertes award, for both of which I am grateful. Dr. Kenneth C. Parkes was especially helpful with suggestions benefiting the manuscript. I wish to thank the following individuals and institutions for the loan of specimens essential to this investigation, and for assistance rendered during visits to certain of the institutions: American Museum of Natural History (Dr. Dean Amadon), Dickey Col- lection of the University of California at Los Angeles (Dr. Thomas R. Howell), Museum of Vertebrate Zoology of the University of California at Berkeley (Dr. Alden H. Miller), Carnegie Museum (Dr. Kenneth C. Parkes), Chicago Natural History Museum (Mr. Emmet R. Blake) Florida State Museum of the University of Florida (Dr. Oliver L. Austin, Jr.), Moore Laboratory of Zoology of Occidental College (Dr. J. W. Hardy), Museum of Comparative Zoology of Harvard University (Dr. Raymond A. Paynter, Jr.), Philadelphia Academy of Sciences (Mr. James Bond), and the U.S. National Museum (Mr. Herbert G. Deignan). LITERATURE CITED Blake, E. R. 1953 Birds of Mexico. Univ. of Chicago Press, Chicago, 111. Chapman, F. M. 1891 On the color-pattern of the upper tail-coverts in Colaptes auratus. Bull. Amer. Mus. Nat. Hist., 3:311-314. Dickey, D. R., and A. J. van Rossem 1928 Further descriptions of new birds from El Salvador. Proc. Biol. Soc. Wash- ington, 41:129-131. 1938 The Birds of El Salvador. Field Mus. Nat. Hist., Zool. Ser., 23, No. 406. Eisenmann, E. 1955 The species of Middle American birds. Trans. Linnaean. Soc. New York, 7:1-128. Griscom, L. 1932 The Distribution of the Bird-life in Guatemala. Bull. Amer. Mus. Nat. Hist., 64:1-439. Lafresnaye, F. de 1844 Oiseaux neuveaux du Mexique. Rev. Zool., 7:41-43. Lester L. Short, Jr. CENTRAL AMERICAN FLICKERS 21 Land, H. C. 1962 A collection of birds from the Sierra de las Minas, Guatemala. W''ilson Bull., 74:267-283. Miller, A. H., H. Friedmann, L. Griscom, and R. T. Moore 1957 Distributional Check-list of the Birds of Mexico. Part II. Pacific Coast Avi- fauna, 33. Peters, J. L. 1948 Check-list of Birds of the World. Vol. 6. Harvard Univ. Press, Cambridge, Mass. Short, L. L., Jr. 1965<7 Hybridization in the flickers (Colaptes) of North America. Bull. Amer. Mus. Nat. Hist., 129:307-428. 19656 Variation in West Indian flickers (Aves, Colaptes). Bull. Florida State Mus., 10:1-42. Stone, W. 1932 The birds of Honduras with special reference to a collection made in 1930 by John T. Emlen, Jr., and C. Brooke Worth. Proc. Acad. Nat. Sci. Phila- delphia, 34:291-342. Test, F. H. 1940 Analysis of plumage coloration in the flickers, avian genus Colaptes. Ph.D. thesis (unpubl.), Univ. California, Berkeley. Wetmore, a. 1941 Notes on the birds of the Guatemalan highlands. Proc. U.S. Natl. Mus., 89:523-581. AMERICAN MUSEUM OF NATURAL HISTORY, NEW YORK, NEW YORK {FORMERLY, BUREAU OF SPORT FISHERIES AND WILDLIFE, WASHINGTON, D.C. ) , 3 AUGUST 1965 THE DOUBLE-SCRATCH AS A TAXONOMIC CHARACTER IN THE HOLARCTIC EMBERIZINAE C. J. 0. Harrison The Holarctic buntings of the sub-family Emberizinae are a relatively uniform group of species, mainly birds of scrub or open plains, with a bill adapted for seed-eating, mostly with a streaked brown plumage and bright specific colouring which is often confined to the head and breast. Morpho- logically they show little differentiation and it is therefore of interest that they appear to be divisible into two groups by a behavioural character, the presence or absence of which does not appear to be determined by, or cor- related with, their immediate needs or surroundings. This is the use of the double-scratch in feeding, shown by many of the North and Central American species. The double-scratch is a rapid backward kick performed simultaneously with both feet which are scraped along the surface of the ground, scratching back the superficial layer and exposing what is beneath. If the movement is watched closely in a relatively long-legged species it will be seen that at the commencement the bird is standing with bill pointing down, apparently looking for food on the ground immediately below the head. Without moving from the spot it then gives a small hop in which both feet are brought for- ward, apparently almost to the spot that it was previously looking at. This movement also tilts the body axis upwards so that the head is raised a little. Immediately after the first hop brings the feet forward a second hop occurs in which the feet are hardly raised hut are brought smartly back to their former position, the claws scratching the surface and throwing back some of the superficial material. This restores the body axis to its original position so that at the end of the movement the bill is pointing down at the place where the scratching occurred. This will presumably enable the bird to observe immediately anything which has been exposed. If no edible items are exposed the movement may be repeated in a rapid series, the bird remaining in the one place. If the substrate is not too hard or compressed the bird may rapidly excavate a sizable hollow. This be- haviour is of obvious advantage to a species feeding in the fallen litter under trees or shrubs or on bare ground, particularly in the winter months when relatively little plant or animal food may be visible at the surface. Among the Emberizinae this scratching movement appears to be confined to American species. It was observed in the Song Sparrow {Melospiza rnelodia), Swamp Sparrow (M. georgiana) , Tree Sparrow {Spizella arhorea) , Fox Sparrow {Passerella iliaca) ^ Rufous-naped Sparrow {Zonotrichia capen- sis) ^ juncos (Junco spp.), and towhees (Pipilo spp.). Records of scratching 22 C J. o TAXONOMIC CHARACTER IN HOLARCTIC EMBERIZINAE 23 Harrison in literature are rather sparse and appear more often as casual comments in popular accounts, but it is also recorded in the following species, Black- throated Sparrow ( Amphispiza bilineata) , Olive Sparrow {Arremonops rufivirgata } , and Green-tailed Towhee (Chlorura chlorura) , (Wetmore et ah, 1964) and for the White-throated Sparrow [Zonotrichia alhicollis) (Peters and Burleigh, 1951). The scratching habits are so marked in this group of species that Vaurie {in Thomson, 1964) refers to “large feet for scratching” as a typical character of the Emberizinae. This ability to scratch in feeding appears to offer an isolating character for a group of species within the Emberizinae which roughly comprises those species sometimes referred to as New World sparrows. In addition to the double-scratch the general characters of the group are a streaked brown plumage with relatively subdued specific signal characters, usually consisting of stripes or patches of varying colour on head and breast; sexual mono- morphism; no eclipse nonbreeding plumage; hopping locomotion; and song usually a repetitive phrase delivered from a perch. It certainly includes the following genera — Spizella, Melospiza, Passer ella, Zonotrichia, Amphispiza, and Arremonops — and is expected to include Passerculus, Ammodramus, Passerherhulus, Ammospiza, Pooecetes, Chondestes, and Aimophila. Related but slightly divergent genera are Junco, with more uniform and sober coloured plumage; and Pipilo and Chlorura, consisting of larger birds, mostly with more uniform colouring, though with conspicuously coloured markings in some species. Of the remaining Holarctic species there are two groups. One is the longspurs of the genera Calcarius and Rhynchophanes. These are birds of open country or tundra. They are terrestrial and normally walk or run, but may hop occasionally. The long hind claw is associated with terrestrialism and a walking gait. As far as is known they do not double-scratch. They show marked sexual dimorphism, the males being boldly patterned and coloured on the head and breast, the females dull in colour with a brown- streaked plumage. The male has a winter eclipse plumage like that of the female. Song is usually delivered in flight. There are four Nearctic species, one of which, the Lapland Longspur (Calcarius lapponicus) also occurs in the Palearctic. The Snow Bunting iPlectrophenax nivalis) an arctic species with a Holarctic distribution, may be a specialised offshoot of this longspur group. It is sexually dimorphic, the female being browner and more streaked, the male having a striking black and white breeding plumage and an eclipse- type nonbreeding plumage. It is terrestrial, usually running or walking, and does not use the double-scratch. Its relative lack of heavy pigmentation 24 THE WILSON BULLETIN March 1967 Vol. 79. No. 1 and denser plumage would appear to be the result of adaptation to arctic conditions. Another odd species that might belong in this group, or else shows similar hut parallel divergence, is the Lark Bunting i Calamospiza melanocorys ) , which shows marked sexual dimorphism, the breeding male being black with a white wing patch while the female is brown-streaked. The male has a non- hreeding eclipse plumage. Like the longspurs it is a mainly terrestrial species of open country but would appear to be much more prone to perch than these. There appears to be no useful information on gait and double-scratching. The other main group of species is that of the typical Old World buntings of the genus Emberiza. These species share with the longspurs the sexual dimorphism, with a brightly patterned head and breast in the male, and an inconspicuous brown-streaked plumage in the female. The male has an eclipse nonbreeding plumage. As a group they differ in being much more arboreal, occupying a similar range of habitats to those occupied by the New World sparrows. They do not use the double-scratch in feeding. Witherby et al. (1938) state that the normal locomotion of these birds is a hop, hut a subsequent series of observations (Woods, 1946; Alexander, 1946, 1947, 1948; Ellis, Rayner, and Williams, 1948; Macpherson, 1949; Wallace, 1957) showed that in at least eight of these species walking or running occurred as well as hopping when the birds were on bare ground. The song is a repetitive phrase delivered from a perch or rock. There is also a monotypic genus in Asia. The Crested Bunting ( Melophus lathami) differs from species of the genus Emberiza in that the male has a distinct crest ( although an incipient crest is present in the Rustic Bunting {E. rustica ) , and a black plumage with brown wings. It is much more ter- restrial in its behaviour and the very inadequate comments in literature appear to infer that it normally walks. It mounts to a low perch to sing. It would appear to be a specialised offshoot of Emberiza, and in some respects forms a parallel to the Lark Bunting of North America. DISCUSSION It is customary to regard the Emberizinae as a group originating within the complex radiation of nine-primaried oscines in the New World. The longspurs must therefore be considered as a specialised group derived from these, while the Old World genera are usually regarded as forms arising from an invasion of New World forms. In view of the probable phylogeny of these groups it is difficult to under- stand the distribution of the double-scratch as a character of behaviour in these species. As a form of feeding behaviour it is obviously of value to a ground-feeding species and might be expected to be of greatest use to a R J. o TAXONOMIC CHARACTER IN HOLARCTIC EMBERIZINAE 25 Harrison terrestrial bird. It is, however, apparently absent in the more terrestrial species and present in more arboreal birds. In addition it is present in one large group of species on one continent and absent from a related group apparently occupying similar niches on another. We cannot therefore dismiss the pattern of presence and absence of this character as evidence of adapta- tion to environment. Since the character is common to a large group of closely related species, the New World sparrows, which show ecological and morphological diversity to a limited degree only, it can be suggested that it may be inherited through a common ancestor. It is, however, absent from the related longspurs and Old World buntings which might have been ex- pected to have also arisen from this ancestral stock. It seems improbable that it should be lost in derived groups which would have equal need of it, and that its present distribution is purely accidental. Another possible explanation would involve reversing the general view on evolutionary spread and suggesting that the New World forms might repre- sent an adaptive radiation from an invasion of Old World bunting stock, and that the ability to use the double-scratch represented a new and further evo- lutionary development lacking in an earlier group. There is a third explanation which would fit both the present view on the evolution of these groups and at the same time explain the distribution of the double-scratch as a behaviour character. Double-scratch is absent from the longspurs although these are a mainly North American group obviously related to the New World sparrows. The major behavioural difference be- tween these two groups, and the one which appears relevant, is that of loco- motion. The sparrows usually hop and the longspurs usually walk or run. There appears to be a direct correlation between hopping and the use of double-scratch in feeding. The description of this scratching already given shows clearly that it is directly derived from hopping. It seems possible that this is true of the scratching methods of feeding when these occur in any of the Passeriformes. Double-scratching occurs in the wydahs (Viduinae), in some of the thrushes (Turdinae ), and babblers ( Timaliidae) , and probably in other groups. In each case it is associated with species in which hopping is the usual mode of locomotion. There is no evidence of this type of scratch- ing in species which normally walk such as the larks ( Alaudidae), wagtails (Motacillidae ) , starlings (Sturnidae), and crows [Corvus spp.). There is not an absolute correlation. The Blackbird iTurdus merula) is a species which both hops and runs. Gibbs and Hartley (1957) refer to one digging first with one foot then the other. One may, however, assume that there is a direct morphological adaptation enabling a bird that hops to scratch in this fashion, and that a change from hopping to walking as the normal mode of progress involves structural changes that result in the loss of the ability to 26 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 use the double-scratch in feeding. It can therefore be supposed that the evolution of the longspur group in bare open country involved the develop- ment of walking and loss of hopping as the normal mode of locomotion and this in turn involved the loss of the double-scratch associated with hopping. The Old World buntings are similar to the New World sparrows but they also show very close links with the longspurs in plumage. Their dual mode of locomotion, which might be inferred to indicate partial adaptation by an arboreal group to terrestrialism, could also be interpreted as indicating the relics of terrestrialism in a group which has secondarily evolved a more arboreal mode of life. It can therefore be proposed as a hypothesis that the Old World buntings in their evolution from the New World sparrow stock have passed through a phase similar to that shown by the longspurs, or share a common ancestry with them; and that during this phase they have lost the ability to use the double-scratch in feeding and have not re-evolved it. Such a derivation would be a reasonable conclusion since the spread of Nearctic Emberizidae into Eurasia would be most likely to have occurred via a northern land-bridge or short sea crossing and would have occurred most easily if the invading stock was adapted to tundra-like conditions and able to exist near the ice-cap. The notion of a common ancestry of longspurs and Old World buntings could be further argued with reference to the close similarity between the Lapland Longspur as the present Eurasian longspur, and the buntings of the Little Bunting {E. pusilla) — Reed Bunting {E. schoenidus) — Rustic Bunting {E. rustica) subgroup. SUMMARY The Holarctic buntings of the subfamily Eml)erizinae can be divided into two groups by the presence or absence of a behavioural character, the use of the double-scratch in feeding. The double-scratch is a rapid backward kick of both feet by which the super- ficial layer of the substrate is scraped hack. It may be repeated in one place until a hollow is made. Within this group this scratching movement is confined to New World sparrows, juncos, and towhees, being known for nine genera and suspected for another seven. These species also show certain common characters of morphology and behaviour as do those of the other groups subsequently mentioned. There are two main groups within the remaining species. The terrestrial Longspurs, with a Holarctic distribution, have a walking locomotion and lack the double-scratch. The Snow Bunting may he related to these, and the Lark Bunting shows similar characters. The other main group is that of the Eurasian Old World buntings, and the monotypic Crested Bunting. These birds usually hop but may walk, and do not use the double-scratch in feeding although occupying similar niches to the New World sparrows. The Old World species are usually regarded as derivatives of New World stock. It is suggested that the double- scratch is associated with hopping locomotion and may be lost by birds that walk; and that the Old World buntings have evolved via a terrestrial walking form similar to the longspurs, and in the process have lost, and failed to re-evolve, the double- scratch mode of feeding. c J. o TAXONOMIC CHARACTER IN HOLARCTIC EMBERIZINAE 27 Harrison ^ • LITERATURE CITED Alexander, W. B. 1946 Gait of Corn Bunting. Brit. Birds, 39:53. 1947 Gait of Yellow Bunting. Brit. Birds, 40:256. 1948 The gait of buntings. Brit. Birds, Ellis, J. C. S., G. W. Rayner, and E. M. Williams 1948 The gait of buntings. Brit. Birds, ^\:2^6-2Kl . Gibb, J., and P. H. T. Hartley 1957 Bird foods and feeding habits as subjects for amateur research. Brit. Birds, 50:278-291. Macpiierson, a. 1949 Gait of buntings. Brit. Birds, 42:32. Peters, H. S., and T. D. Burleigh 1951 The birds of Newfoundland. Houghton Mifflin, Boston. Thomson, A. L. 1964 A new dictionary of birds. Nelson, London. Wallace, D. I. M. 1957 Little Buntings in Middlesex. Brit. Birds, 50:208-209. Wetmore, a. et al. 1964 Song and garden birds of North America. Nat. Geogr. Soc. Washington, WiTiiERBY, H. F. et al. 1938 The handbook of British birds. Vol. 1. Witherhy; London. Woods, H. E. 1946 Gait of Corn Bunting. Brit. Birds, 39:348. BRITISH MUSEUM (NATURAL HISTORY) CROMWELL ROAD, LONDON, ENGLAND, 8 OCTOBER 1965 MOVEMENTS OE EEMALE RUFEED GROUSE DURING THE MATING SEASON' Robert B. Brander Knowledge of sexual relationships in the Ruffed Grouse [Bonasa umbel- liis) is inchoate. Displays related to mating have been described ( Allen, 1934; Bump et ah, 1947), but two basic questions remain unanswered in the literature. Is the hen attracted to the site of the cock’s drumming per- formance, and do the cock and hen form a pair-bond that is more than transitory? Hens, and cocks to a lesser degree, are seldom observed because of their cryptic behavior within dense vegetation. For this reason, reports on mating behavior have been deductions supported either by general observation in the field or by extrapolation of observations on captive birds. Bent (1932, p. 146 ) did not comment on pair-bonding, but he did speculate that the cock leaves its drumming log and seeks out the hen. Roberts ( 1932, p. 380) apparently favored the “opinion” that the Ruffed Grouse is polygy- nous. Leopold (1933, p. 104 ) considered the mating behavior to be similar to that of the Ring-necked Pheasant { Pliasianus colchicus) . in which each male has its own separate group of hens. Grange (1948, p. 192 ) did not know whether Ruffed Grouse pair or are polygamous, but he “guessed” that they pair for the season, while Edminster (1954, p. 231) stated that the Ruffed Grouse is promiscuous in its breeding habits. Lack (1940) de- veloped a classification for pair-formation in birds and placed the Ruffed Grouse among those species in which the sexes meet solely for copulation and in which the female goes to the solitary male at its display site. Allen (op. cit. ), after 15 years of study of captive Ruffed Grouse, pre- sented evidence which allows interpretation of the duration of the pair-bond. To complete the sequence of events described by Allen — synchronization of mating cycles, dominance, copulation — would require, it seems to me, at least a few days. Pair-bonding would not be a transitory affair and polygyny is indicated. Bump et al. (op. cit.), after a long-term study of captive birds, observed the reactions on which Allen’s conclusions were based. They did not believe that a synchronizational period is necessary to ensure fertilization of eggs. It seemed probable to them that the female in the wild would seek out the male in his territory; if they were both in the proper stage, copulation would take place; if not, the hen would retire to return later or to move on to another drumming male. Because of a postulated evenness of the sex ratio ^ Paper No. 5842, Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul, Minnesota 55101. 28 Robert B. Brander MOVEMENTS OF FEMALE RUFFED GROUSE 29 and the dispersed nature of the mating birds, the likelihood of a hen moving on to another male would be slight, and this, they reason, would be tan- tamount to “enforced monogamy.” These observations and studies have yielded valuable information but as Lack noted many years ago (1940), studies on the mating behavior of captive Ruffed Grouse do not necessarily apply to wild birds. However, only recently (see Marshall and Kupa, 1963) was the technique of radio-telemetry adapted for use on Ruffed Grouse and thereby made possible the study of that bird’s behavior under field conditions. I have used the telemetric method to obtain data on the basic question of pair-bonding in Ruffed Grouse. These are, I believe, the first field data on this behavior. This study was done during the spring of 1963 at the Gloquet Forest Research Genter, University of Minnesota. Gullion et al. (1962) have described briefly the soils, topography, and vegetation of the Station. In general, peat soils supporting black spruce iPicea mariana), balsam fir (Abies balsamea), and larch (Larix laricina) are found in the lowlands; the aspens (Populus spp.), white birch (Betula papyrifera), white spruce (Picea glauca), and jack and red pines (Pinus banksiana and P. resinosa) predominate on the loamy- sand uplands. METHODS Because cocks seldom left their drumming-activity centers (the immediate area around a drumming log according to Gullion et al., 1962 ) , the problem of pair-bonding was best attacked through a study of the movements of hens. Radio-tracking was initiated in February so that home range boundaries were well defined before the breeding season began. I succeeded in radio-track- ing three hens (all immatures) through their mating activities and onto their nests. An additional hen (an adult) was tracked but I failed to find her nest. The birds were taken in “lily-pad” traps and leg bands were affixed as detailed by Gullion (1965). A radio-transmitter package modified from that of Marshall and Kupa (1963 ) as described by Brander (1965 ) was then attached. Both the performance of the female birds in flight and their participation in social behavior indicated that the movements to be described are not significantly different from those of unmarked birds. As a rule, three precise locations were determined daily for each bird. Precision was of an order which allowed placement of a bird within a quadrat 33 feet square (0.025 acres). Locations were taken at mid-morning, mid-afternoon, and during the night-roost period. Transmitter signals were also monitored several times during the day so that the general location of a bird was under rather constant surveillance. The locations of all drumming-activity centers were also known. At least 30 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Calculated Dates of Table 1 First Egg and Oestrus for Three Hens Bird number Date on nest Number eggs First egg Oestrus 1826 23 May 9 9 May 3- 6 May 1944 19 May 6 11 May 5— 8 May 1828 24 May 8 13 May 7-10 May two cocks within the study area were associated with drumming-activity centers but did not engage regularly in drumming performances. For purposes of evaluation, I used information in the literature to cal- culate the probable dates on which certain responses by the hens might occur. On the average, Ruffed Grouse lay two eggs each three days until the clutch of 9 to 14 eggs is complete (Bump et al., 1947). Knowing the number of eggs laid by a certain date, one may derive the date of first egg. Bump et al. ( op. cit.) also determined that captive hens were in oestrus three to seven days prior to the laying of the first egg, the shorter period being more frequent. The onset of oestrus was abrupt and if the hen were mated promptly, oestrus ceased almost at once, but otherwise it lasted for three to five days. [Oestrus is a term usually reserved for the class Mammalia (Bullough, 1961) but Allen (1934) and Bump et al. (1947) apply it to the Ruffed Grouse and I follow their usage.] Using this information, I calculated the date of first egg for the three hens and the dates that each hen might have been in oestrus. The results are presented in Table 1. Location and movement maps for the theoretical oestrous period were constructed. These maps and interpretations are now considered for each bird in turn. RESULTS Hen No. 1826. — The movement pattern of this bird from the morning of 1 May to the morning of 10 May is given in Figure 1. Actually, the mating season for this hen was adumbrated by her response to drumming activity, first on 25 April then on 27 and 28 April. On each of these dates she moved a short distance in the direction of a drumming-activity center hut returned to her established winter range, a well defined area of 26 acres. The drumming of DRl (Fig. 1) and another male in that area were, apparently, the stimuli involved. Nothing more than movement response was indicated. Then, on 1 May, she made a long northerly movement toward an activity center but returned to her winter range that same evening. She did not approach the drummer (DR2) which, probably, elicited her movement response. On 3 May she again made a move to the north, and this time approached the drumming log of DR2. After spending the night in a larch stand 500 feet west of his log, she returned to her winter range. This was followed the next day (5 May) by a shorter northerly probe and retreat. The next move, on 6 May, was unalterably to the north. Supposedly, 6 May was the Robert B. MOVEMENTS OF FEMALE RUFFED GROUSE 31 Fig. 1. Immature female, No. 1826. Movements and locations during oestrus, 1-11 May. The 1 May location is in the southwestern part of the figure. DR and black rectangle indicates a drumming male. Circles, squares, and triangles represent mid- morning, mid-afternoon, and night-roost locations respectively. last day of oestrus (Table 1). Open symbols are employed in Figure 1 for locations thereafter (7, 8, 9, and 10 May). She had already visited the activity center of one drummer (DR2) and then begi n another series of visits. On 7 May she visited the center of DR3. This northeasterly movement with return on 8 May was especially interesting since there were no active drummers in that area but a tree planting crew using a tractor was there. I think that her movement to within a few feet of this operation represented a response to a false stimulus, the tractor, which was roughly analogous to that of a response to drumming. Bump et al. (1947, p. 263-264) report several instances where grouse, of unspecified sex, responded to tractor and wood chopping sounds. A final overt response to drumming activity occurred the following day (9 May) when she moved eastward and remained overnight within the activity center of DR4. On 10 May she returned to the habitat in which she was to nest. Indications are that the first egg was laid on that date. Also, indications are that oestrus began seven days prior (3 May) to the first egg and ended the day before. Calculated oestrous dates and egg laying rates as described in Bump et al. (op. cit.) seem reasonably valid when applied to hen number 1826. According to Bump et al. (op. cit., p. 267) oestrus in captives ceases almost im- 32 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Fig. 2. Immature female, No. 1828. Movements and locations during oestrus, 4-11 May. The 4 May movement is from the north (arrow). DR and black rectangle indicate a drumming male while NDR indicates a less persistent drummer. Other symbols are as in Fig. 1. mediately after copulation. Assuming that wild grouse react similarly, I interpret the mating behavior of hen No. 1826 as follows: (1) oestrus, per se, commenced on 6 May; she responded to a drumming male on that date but did not copulate; (2) she responded to another male on 7 May and again did not copulate; (3) she responded to a false stimulus on 8 May; (4) successful copulation occurred on 9 May after she had responded to the third male within her range. This hen, without question, was attracted to the activity centers of drumming cocks, and sounds produced by the cocks were the proximate stimuli which elicited her response. The pair-bond was transitory, probably of a duration no longer than a few hours. Because the cocks continued to drum after the hen had left their respective activity centers and, I presume, continued to attract hens, this mating behavior is properly termed promiscuous. Even if the as- sumption of a single copulation were not warranted, the behavior remains promiscuous. Hen \o. 1828. — Tlie mating season for this bird was foreshadowed on the morning of 25 April when she moved toward the sound of drumming activity. However she remained within her tightly defined winter range (7 acres) until 4 May. Figure 2 shows her movements from that date through the oestrous season. She moved into a drumming activity center on 6 May and it seems certain that oestrus commenced on that date. Her movements indicated a responsiveness to drumming at least through 10 May. The persistent drumming of an adult cock (DR, Fig. 2) probably signaled the hen’s departure from the winter range, but a much less per- sistent drummer (NDR) along her path of movement may have seeured her attention also. Robert B. Braiulcr MOVEMENTS OE FEMALE RUFFED GROUSE 33 Fig. 3. Immature female, No. 1944. Movements and locations during oestrus, 4-11 May. The 4 May location is in the southwestern part of the figure. See Fig. 1 for explanation of symbols. I interpret her mating behavior as follows: <1) oestrus, per se, commenced on 6 May; (2) copulation probably occurred on 9 or 10 May. This hen, as with number 1826, was unquestionably attracted by the sound of a drumming cock. While the map of her movements and locations during the oestrous period may suggest a pair-bond of some duration, particularly with NDR, observations during that period indicated that lengthy juxtaposition of the sexes was circumstantial. Because the cocks continued to drum after the hen had established her nest, this behavior was promiscuous. Hen No. 1944. — Hen number 1944 was radio-marked on 26 April. An overt response to drumming was noted on 29 April when she moved toward an activity center which included two males. Another precursory response was noted on 1 May. Figure 3 shows her movements from 4 May through the oestrous period. The long movement to the northeast and into the range of a drumming male ( DR in Fig. 3) probably marked the first day of oestrus; which was identical with the postulated onset date for hens 1826 and 1828 — 6 May. After spending two days within audible range of the drummer, she returned to his activity center on 9 May and then into her nesting habitat on 10 May. A “non-drumming"’ male (NDR, Fig. 3) might have influenced the hen's movements, hut I was reasonably sure that this did not occur. The mating behavior of hen No. 1944 is interpreted as follows: (1) oestrus, per se, commenced on 6 May; (2) copulation probably occurred on 9 or 10 May. As with the other hens. No. 1944 was attracted by the sound of drumming to the activity center of a cock. No more than a transitory pair-bond developed and the behavior of both cock and hen indicated promiscuous mating. DISCUSSION A Basic question on the behavior of Ruffed Grouse was answered when hens were observed responding: positively to drumming; cocks. The (juestion of the duration of the pair-bond was not answered conclusively, hut the 34 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Table 2 Patterns of Mating Behavior in Females as Related TO Time Behavior pattern Bird number Pre-oestrus Oestrus Adumbration Prelude Mating Copulation 1826 25 April 1 May 6 May 9 May 1828 25 April 4 May 6 May 9 or 10 May 1944 9 24 April 6 May 9 or 10 May evidence is highly suggestive that the sexes meet solely for copulation and that the mode of sexuality is promiscuous. Promiscuity is a generic term which does not adequately depict the intricate pattern made manifest in the movements of the three hens. Actuallv, four levels of response are apparent in the pattern and these I term: adumbration: passive restlessness to drumming: prelude: overt restlessness to drumming; mating: proximal movement; copulation: nidification. Mating and cop- ulatory phases comprise oestrus per se. Onset dates for each of the phases are given in Table 2. The patterns of responsiveness for the hens are strikingly similar and suggest that stimuli, internal and external, are also arranged in a precise pattern. There is other evidence that this is so. Data provided by Gullion ( unpublished MS. I from a four-year study, also at Cloquet, Minnesota, indicate that the period of most intensive drumming activity is precisely fixed in time. In his study, males exposed to extremely variable annual meteorological and phyto- phenological conditions still reached a peak in their drumming activity within 3 days of 29 April. The peak was on 26 April in 1963, which coincides with the adumbration phase of the behavior that I describe. An inflexible pattern of mating has adaptive significance for birds faced with extremes in wintering conditions. The periods of net loss in energy storage must be balanced in the animal by periods of net gain. For northern species these periods are rather rigidly fixed. The stress of winter begins in early November, ends in early April, and is followed in quick order by the stresses of mating, egg-laying, incubation, and care of young. Except for a brief respite in April, these all may be periods of net losses in energy. A scant two to three months remain for the hen to recoup her losses. There- fore, a prolonged mating season becomes a luxury ill-afforded to endemic northern species, and an inflexible breeding season which results from rigid behavioral patterns should not be unexpected in the Ruffed Grouse of north- ern Minnesota. Robert B. Krander MOVEMENTS OF FEMALE RUFFED GROUSE 35 SUMMARY A radio-telemetric system was used to obtain data on sexual relationships in the Ruffed Grouse. The hen was attracted to the site of the cock’s drumming performance but no more than a transitory pair-bond developed. A promiscuous mating habit was in- dicated. The movements of hens suggested varying levels of response to the stimuli of mating, and responses were precisely fixed among hens and in time. Such an inflexible pattern of mating has adaptive significance for Ruffed Grouse which winter in the rigorous climate of northern Minnesota. ACKNOWLEDGMENT This paper is a contribution from a project supported by National Science Foundation Grant No. GB-1345. The data from the current research on Ruffed Grouse at the Cloquet Forest Research Center and the technicjues developed therein were essential to this project. William H. Marshall and Gordon W. Gullion provided these data and participated in many ways during the field work. Phillip Schladweiler, James Forbes, and David Peterson were able field assistants. Frederick Greeley and David K. Wetherhee offered valuable criticism of the manuscript. LITERATURE CITED Allen, A. A. 1934 Sex rhythm in the Ruffed Grouse (Bonasa umbellus Linn.) and other birds. Auk, 51:180-199. Bent, A. C. 1932 Life histories of North American gallinaceous birds. U.S. Natl. Mus. Bull. 162. Brander, R. B. 1965 Factors affecting dispersion of Ruffed Grouse during late winter and spring on the Cloquet Forest Research Center, Minnesota. Ph.D. Thesis, Univ. of Minnesota, Bullougii, W. S. 1961 Vertebrate reproductive cycles. John Wiley and Sons, Inc., New York. Bump, G., R. W, Darrow, F. C. Edminster, and W. F. Crissey 1947 The Ruffed Grouse. New York State Conserv. Dept., Albany. Edminster, E. C. 1954 American game birds of field and forest. Chas. Scribner’s Sons, New York. Grange, W. B. 1948 Wisconsin grouse problems. Wisconsin Conserv. Dept., Madison. Gullion, G. W. 1965 Improvements in methods for trapping and marking Ruffed Grouse. /. W’ildl. L/gmC, 29:109-116. Gullion, G. W., R. T. King, and W. H. Marshall 1962 Male Ruffed Grouse and thirty years of forest management on the Chupiet Forest Research Center, Minnesota. /. Forestry, 60:617-622. Lack, D. 1940 Pair-formation in birds. Condor, 42:269-286, Leopold, A. 1933 Game management. (Jias. .Scribner's .Sons, New t Ork. 36 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Marshall, W. H., AND J. J. Klpa , for Ruffed Grouse studies. Trans. 1%3 Development of radio-telemetry techniques tor nut North Amer. Wildl. Coni., 28:443-456. Roberts, T. S. . ^ Minnesota Press, Minneapolis. 1936 The birds of Minnesota. \ ol. 1. Lniv. SACHUSETTS. AMHERST, MASSACHUSETTS, -* new life member Dr. Donald J. Borror, of Columbus Ohio a ne« Life Member of The Wilson Ornithological Society. Dr. Borror holds decrrees from Otterbein College, and The Ohio State L'niversity, and is current y Professor of Zoology and Entomology^ at Ohio State. Ornithologists know Dr. Bor- ror as one of the pioneers in the recording of bird songs and the analysis of these recordings bv audiospectrographic means. He is the author of numerous papers on bio-acoustics, and has also published sev- eral phonograph records of bird songs. He has also co-authored a popular text- book in entomology, and has publishe many papers on that subject. He is a member of the .\OU, the Entomological Society of America, Society of Systematic Zoology, and the American Association for the Advancement of Science. Dr. Borror is married, and has one son, who following in his father's footsteps, is a professor of zoology. WEIGHTS OF BIRDS FROM ALABAMA AND NORTH CAROLINA Paul A. Stewart and Robert W. Skinner IN Alabama and North Carolina from 1958 to 1963 we weighed 363 birds of 102 species and 2 hybrids. Some of the birds were collected in pesticide-bird studies of the U.S. Fish and Wildlife Service; others were col- lected in a program of the Alabama Department of Conservation to build up an educational collection of bird skins; the remainder were banded and released. In Alabama, most of the birds were collected in Montgomery County, but some were taken at locations scattered over the State. All of the North Carolina collections were made at the Hydrologic Experiment Station near Asheville. Our list of birds for which weights were obtained contains 63 species and 2 hybrids not weighed by Norris and Johnston (1958. Wilson Bull. 70:114-129) who collected in Georgia and South Carolina. It seems desirable, therefore, to publish these additional data on bird weights from the southeastern United States. Because of the smallness of the sample in individual categories, no deductions are attempted. METHODS The birds collected in Alabama by the senior author were taken in bait traps and were immediately either killed or weighed and released; those taken in North Carolina were mist-netted and immediately killed. The specimens taken by the junior author were shot. All birds killed by both authors were placed in plastic bags and in refrigeration soon after collection. Weights were taken when the birds were removed from refrigeration 2-60 days later. Presumably it might have been desirable to have weighed the birds immediately after capture. Based chiefly on studies with mammals. Banks ( 1965. /. Mammal. 46:110), however, concluded that, with specimens kept in refrigeration up to three months, “the change in weight caused by freezing is negligible.” The hours when the birds were captured varied but were not recorded. The smaller birds were weighed on a Chatillon spring balance provided by the U.S. Fish and Wildlife Service; larger birds were weighed on a double-beam balance. In most cases individual weights were taken only to the nearest 0.5 g. The birds collected for skins were aged by checking the degree of ossifica- tion of the skull or by plumage characters. They were sexed by examination of the gonads. Because it was difficult to avoid cross-contamination, the birds collected for chemical analysis of jiesticide residues were not dissected for aging and sexing, but. like the birds handed and released, were aged and sexed by external characters when possible. Sex or age were not obtained for some birds. Detailed data are presented in Table 1. 37 38 THE WILSON BULLETIN March l')67 Vol. 79, No. 1 Table 1 Weights (Grams) of Birds with Species, Age, Sex, Date and State of Collection Common Loon iGavia immer) — Female, adult, 28 April, Alabama: 2,891.6. Horned Grebe iPodiceps auritiis) — Male, immature, 15 February, Alabama: 515.0. Fe- male, immature, 17 March, Alabama: 384.0. Gannet i Morns bassanus) — Male, immature, 17 March, Alabama: 2,948.3. Female, adult, 17 March, Alabama: 3,061.7. Canada Goose (Bronta canadensis) — Female, adult, 21 December, Alabama: 3,855.5. Fe- male, adult, 29 December, Alabama: 3,628.7. Lesser Snow Goose {Chen hyperborea) — Male, adult, 16 October, Alabama: 1,814.4. Mallard (Anas platyrhynchos) — Male, adult, 8 December, Alabama: 1,170.0; 1,345.0; 1.372.0. Female, adult, 8 December, Alabama: 1,180.0; 1,393.0. Black Duck (Anas rubripes) — Male, adult, 6 December, Alabama: 1,200.0. Mallard X Black Duck — Unsexed, adult, 8 December, Alabama: 1,370.0. Pintail (Anas acuta) — Male, adult, 28 December, Alabama: 802.0. American Widgeon (Mareca americana) — Male, adult, 1 December, Alabama: 558.0. Male, adult, 27 December, Alabama: 789.0. Male, adult, 29 December, Alabama: 713.0. Female, adult, 6 December, Alabama: 696.0. Wood Duck {Aix sponsa) — Male, adult, 26 December, Alabama: 587.0. Canvasback (Aythya valisineria) — Male, adult, 29 December, Alabama: 1,086.0. Lesser Scaup (Aythya af finis) — Female, adult, 29 December, x\labama: 499.0. Bufflehead ( Encephala albeola) — Female, adult, 12 December, Alabama: 389.0. Hooded Merganser (Lophodytes cucuUatus) — Male, adult, 26 December, Alabama: 748.5. Female, adult, 26 December, Alabama: 518.0. Mississippi Kite (Ictinia misisippiensis) — Male, adult, 7 May, Alabama: 260.0. Female, adult, 24 August, Alabama: 297.7. Cooper’s Hawk ( Accipiter cooperii) — Female, adult, 30 January, Alabama: 609.5. Red-tailed Hawk (Buteo jamaicensis) — Male, immature, 27 August, Alabama: 963.9. Male, immature, 14 December, Alabama: 878.8. Male, immature, 27 January, Alabama: 949.9. Female, immature, 2 November, Alabama: 1,190.7. Female, immature, 19 Novem- ber, Alabama: 1,190.7. Female, immature, 9 December, Alabama: 1,105.6. Female, im- mature, 16 December, Alabama: 1,389.1. Female, immature, 20 January, Alabama: 1,190.7. Female, immature, 26 February, Alabama: 907.2. Female, immature, 7 March, Alabama: 1,048.9. Female, immature, 9 March, Alabama: 1,162.3. Red-shouldered Hawk (Bnteo lineatns) — Male, adult, 1 December, Alabama: 491.6. Male, immature, 19 October, Alabama: 680.4. Female, immature, 23 November, Alabama: 878.8. Female, adult, 14 December, Alabama: 595.3. Female, adult, 5 January, Alabama: 567.0. Female, immature, 29 November, Alabama: 708.7. Female, adult, 16 January, Alabama: 708.7. Female, adult, 25 April, Alabama: 680.4. Broad-winged Hawk (Buteo platypterus) — Male, adult, 13 July, Alabama: 340.2. Unsexed, unaged, 20 April, Alabama: 311.0. Golden Eagle (Aquila chrysaetos)- — Female, immature, 28 January, Alabama: 4,365.8. Marsh Hawk (Circus cyaneus) — Male, adult, 17 November, Alabama: 3%.9. American Kestrel (Falco sparverius) — Male, adult, 29 December, Alabama: 103.0. Male, adult, 28 January, Alabama: 107.0. Female, adult, 18 September, Alabama: 118.0. Fe- male, adult, 29 September, Alabama: 125.0. Female, adult, 20 October, Alabama: 111.0. Female, adult, 9 December, Alabama: 117.0. Female, adult, 8 January, Alabama: 123.0; Stewart and Skinner BIRD WEIGHTS 39 Table 1 {Continued) Weights (Grams) of Birds with Species, Age, Sex, Date and State of Collection 113.0. Female, adult, 12 January, Alabama: 134.0. Female, adult, 26 January, Alabama: 131.0. Female, adult, 28 January, Alabama: 124.0. Female, adult, 18 March, Alabama: 119.0. Coot iFulica americana) — Unsexed, adult, 11 December, Alabama: 617.0. Killdeer (Charadrius voci ferns) — Female, adult, 8 January, Alabama: 104.0; 114.5. Un- sexed, adult, 9 January, Alabama: 104.0. Black-bellied Plover (Squatarola squatarola) — Male, adult, 4 January, Alabama: 198.0. Common Snipe (Capella gallinago) — Male, adult, 4 January, Alabama: 86.0. Least Sandpiper (Erolia minutilla) — Female, adult, no date, Alabama: 20.0. Herring Gull iLarus argentatus) — Unsexed, adult, 17 March, Alabama: 1,234.0. Ring-billed Gull iLarus delawarensis) — Male, adult, 15 February, Alabama: 499.0. Male, immature, 15 February, Alabama: 464.0. Female, immature, 15 February, Alabama: 432.0. Royal Tern iThalasseus maximiis) — Female, adult, 15 February, Alabama: 492.0. Mourning Dove iZenaidura macroura) — Male, adult, 4 January, Alabama: 120.0. Barn Owl ( Tyto alba) — Male, adult, 8 January, Alabama: 567.0. Screech Owl iOtus asio) — Female, adult, 7 January, Alabama: 130.0. Great Horned Owl {Bubo virginianus) — Male, adult, 6 February, Alabama: 1,291.0. Fe- male, adult, Alarch, Alabama: 1,590.0. Barred Owl iStrix varia) — Female, adult, 22 January, Alabama: 708.7. Unsexed, adult, 23 January, Alabama: 785.5. Short-eared Owl (Asio jlammeus) — Male, adult, 3 February, Alabama: 340.2, Female, adult, 15 January, Alabama: 368.5; 452.5. Unsexed, adult, 25 November, Alabama: 368.5. Red-beaded Woodpecker (Melanerpes erythrocephalus) — Female, adult, 30 May, Alabama: 72.0. Yellow-bellied Sapsucker i Sphyrapicus varius) — Male, adult, 12 January, Alabama: 47.3. Downy Woodpecker ( Dendrocopos pubescens) — Female, adult, 17 March, Alabama: 21.0. Acadian Flycatcher (Empidonax virescens) — Unsexed, adult, 8 July, North Carolina: 13.0. Unsexed, adult, 10 July, North Carolina: 10.0; 12.0. Least Flycatcher (Empidonax minimus)- — Male, adult, 28 April, Alabama: 10.0. Blue Jay ( Cyanocitta cristata) — Male, adult, 7 May, Alabama: 75.0. Tufted Titmouse (Parus bicolor) — Unsexed, immature, 9 July, North Carolina: 19.0; 19.0. Brown-headed Nuthatch (Sitta pusilla) — Male, adult, 4 January, Alabama: 11.0. Long-billed Marsh Wren (Telmatodytes palustris) — Male, adult, 22 January, Alabama: 11.0. Short-billed Marsh Wren (Cistothorus platensis) — Male, adult, 22 January, Alabama: 8.0. Catbird ( Dumetella carolinensis) — Male, adult, 24 April, Alabama: 35.0. Female, adult, 4 June, Alabama: 33.0. Brown Thrasher (Toxostoma rufum) — Male, adult, January, Alaliama: 81.0. Female, adult, 27 December, Alabama: 79.0. Robin (Turdus migratorius) — Female, adult, 11 February, Alabama: 87.0. Wood Thrush i Hylocichla mustelina) — Male, adult, 8 July, North Carolina: 44.0. Male, adult, 10 July, North Carolina: 46.0. Female, adult, 8 July, North Carolina: 45.0; 48.0. Female, adult, 9 July, North Carolina: 43.5; 45.0; 47.6. 40 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Table 1 {Continued) Weights (Grams) of Birds with Species, Age, Sex, Date and State of Collection Hermit Thrush i Hylocichla guttata) — Female, adult, January, Alabama: 32.0. Female, unaged, 11 February, North Carolina: 32.0. Veery [Hylocichla fuscescens) — Male, adult, 9 July, North Carolina: 31.0. Male, adult, 10 July, North Carolina: 26.5; 29.5. Colden-crowned Kinglet [Regulus satrapa) — Male, adult, 4 January, Alabama: 5.0. Ruby-crowned Kinglet (Regulus calendula) — Male, adult, 8 April, Alabama: 8.0. Water Pipit ( Anthus spinoletta) — Male, adult, 4 January, Alabama: 24.5; 24.5; 25.0. Male, adult, 8 April, Alabama: 34.0; 37.0. Cedar Waxwing (Bombycilla cedrorum) — Male, adult, 8 April, Alabama: 34.0; 37.0. Fe- male, adult, 8 April, Alabama: 35.0. Unsexed, adult, 1 February, Alabama: 35.0. Loggerhead Shrike (Lanius ludovicianus) — Male, adult, 3 February, Alabama: 38.0. Male, adult, 10 March, Alabama: 49.0. Starling (Sturnus vulgaris) — Unsexed, unaged, 7 January, Alabama: 71.0; 71.5; 73.0; 73.0; 73.0; 73.5; 75.0; 75.5; 76.5; 77.0; 77.0; 77.0; 77.5; 78.0; 79.0; 79.0; 79.5; 79.5; 80.0; 80.0; 80.0; 80.5; 81.0; 81.0; 81.0; 82.0; 82.0; 82.0; 82.5; 83.0; 83.0; 84.5; 84.5; 85.0; 88.5. Solitary Vireo ( Vireo solitarius) — Female, immature, 9 July, North Carolina: 16.0. Red-eyed Vireo {Vireo olivaceus) — Male, adult, 9 July, North Carolina: 15.0; 17.0. Fe- male, adult, 10 July, North Carolina: 13.0; 14.0. Black and White Warbler ( Mniotilta varia) — Unsexed, immature, 8 July, North Carolina: 8.0; 8.0; 9.0; 9.0; 10.0; 10.5; 11.0; 11.5. Worm-eating Warbler (Helmitheros vermivorus) — Unsexed, immature, 10 July, North Carolina: 12.0; 12.5; 12.5. Blue-winged Warbler ( V ermivora pinus) — Male, adult, 27 April, Alabama: 9.0. Brewster’s Warbler {V ermivora chrysoptera X V ermivora pinus) — Male, adult, 26 April, Alabama: 9.0. Orange-crowned Warbler iV ermivora celata) — Female, adult, 11 February, Alabama: 9.0. Nashville Warbler ( V ermivora rujicapilla) — Male, adult, 26 April, Alabama: 8.0. Black-throated Blue Warbler (Dendroica caerulescens) — Male, adult, 8 July, North Caro- lina: 11.0. Unsexed, immature, 10 July, North Carolina: 8.5. Black-throated Green Warbler (Dendroica virens) — Female, adult, 21 January, Alabama: 9.0. Chestnut-sided Warbler (Dendroica pensylvanica) — Female, adult, 26 April, Alabama: 9.5. Unsexed, immature, 8 July, North Carolina: 9.5; 10.0. Bay-breasted Warbler (Dendroica castanea) — Male, adult, 2 May, Alabama: 12.0. Blackpoll Warbler (Dendroica striata) — Male, adult, 6 May, Alabama: 12.0. Pine Warbler (Dendroica pinus) — Male, adult, 4 January, Alabama: 12.0. Female, adult, 4 January, Alabama: 12.5. Ovenbird iSeiurus aurocapillus) — Male, adult, 9 July, North Carolina: 17.5; 19.0. Fe- male, adult, 9 July, North Carolina: 17.0; 17.5; 17.5; 18.0; 18.5. Unsexed, immature, 9 July, North Carolina: 16.0; 16.0; 16.0; 16.5. Kentucky Warbler (Opornis jormosus) — Male, adult, 8 July, North Carolina: 13.0. Fe- male, adult, 9 July, North Carolina: 13.0. Unsexed, immature, 9 July, North Carolina: 13.0. Yellow-breasted Chat (Icteria virens) — Male, adult, 13 May, Alabama: 25.0. Stewart anil Skinner BIRD WEIGHTS 41 Table 1 {Continued) Weights (Grams) of Birds with Species, Age, Sex, Date and State of Collection Hooded Warbler ( W^ihonia citrina) — Male, adult, 9 July, North Carolina: 11.0; 11.5. Canada Warbler {Wilsonia canadensis) — Male, adult, 5 May, Alabama: 10.0. Female, adult, 8 July, North Carolina: 10.0; 11.0. House Sparrow (Passer domesticus) — Male, adult, 4 January, Alabama: 37.5; 37.5; 39.0; 39.0; 40.0. Eastern Meadowlark (Sturnella inagna) — Male, adult, 27 December, Alabama: 116.0. Fe- male, adult, 11 February, 90.0. Female, adult, 27 December, Alabama: 85.0. Western Meadowlark (Sturnella neglecta) — Male, adult, 28 February, Alabama: 112.0. Female, adult, 3 February, Alabama: 99.0. Redwinged Blackbird (Agelaius phoeniceus) — Male, adult, 11 February, Alabama: 71.0. Male, adult, 14 February, Alabama: 65.0. Male, immature, 9 January, Alabama: 62.0; 64.0; 64.0; 65.0; 65.5; 66.0; 67.0; 67.0; 68.0; 68.5; 68.5; 68.5; 68.5; 69.0; 69.0; 69.0; 70.0; 71.0; 71.0. Female, adult, 22 December, Alabama: 41.0; 45.0; 46.8; 50.0. Orchard Oriole (Icterus spurius) — Male, immature, 29 April, Alabama: 22.0. Baltimore Oriole (Icterus galbula) — Female, adult, 6 May, Alabama: 40.0. Rusty Blackbird (Euphagus carolinus) — Male, adult, 17 January, Alabama: 62.6. Male, adult, 5 February, Alabama: 66.0. Female, adult, 5 February, Alabama: 54.5. Common Crackle (Quiscalus quisciila) — Male, adult, 17 December, Alabama: 130.0. Male, adult, 1 January, Alabama: 135.0. Male, adult, 27 January, Alabama: 112.0. Fe- male, adult, 12 January, Alabama: 109.0. Brown-headed Cowbird (Molothrus ater) — Male, adult, 6 January, Alabama: 42.0; 44.0; 44.0; 45.0; 45.0; 46.0; 47.0; 48.0; 48.0; 49.0; 49.0; 49.0; 50.0; 50.0; 50.0; 50.0; 50.0; 50.0; 51.0; 51.0; 51.0; 51.0; 51.5; 52.0; 52.0; 52.4; 52.5; 53.0; 54.0; 54.0; 54.0; 55.0; 56.0; 56.0; 56.5; 58.5; 58.5; 60.0. Female, adult, 22 December, Alabama: 40.1; 41.5; 44.2; 44.8. Female, adult, 6 January Alabama: 34.0; 35.0; 35.5; 37.5; 37.5; 37.5; 37.5; 39.0; 40.0; 40.5; 41.0; 42.0; 42.5. Scarlet Tanager (Piranga olivacea) — Male, adult, 8 July, North Carolina: 29.5. Female, adult, 10 July, North Carolina: 27.5; 29.0. Female, immature, 10 July, North Carolina: 28.0. Cardinal ( Richmondena cardinalis) — Female, adult, 8 July, North Carolina: 40.0. Female, immature, 10 July, North Carolina: 35.0. Rose-breasted Grosbeak ( Pheucticus liidovicianus) — Female, adult, 2 May, Alabama: 43.0. Male, adult, 30 April, Alabama: 46.0. Indigo Bunting (Passerina cyanea) — Male, adult, 8 July, North Carolina: 12.5; 15.5. Fe- male, adult, 8 July, North Carolina: 13.0; 13.0. Purple Finch (Carpodacus purpureus) — Male, adult, 26 January, Alabama: 24.4. Female, adult, 26 January, Alabama: 22.5; 23.6; 25.3; 25.9; 26.1; 26.4; 26.7; 26.9; 27.0; 27.2; 27.2; 27.3. American Goldfinch (Spinus tristis) — Male, adult, 11 February, Alabama: 14.0. Male, adult, 17 March, Alabama: 13.0. Rufous-sided Towhee (Pipilo erythrophthalmus ) — Male, adult, 8 July, North Carolina: 42.0. Savannah Sparrow ( Passerculus sandwichensis) — Female, adult, 4 January, Alabama: 23.0. Female, adult, 9 January, Alabama: 17.0. Female, adult, 26 February, Alabama: 16.0. 42 THE WILSON BULLETIN Marcli 1967 Vol. 79, No. 1 Table 1 [Continued] Weights (Grams) of Birds with Species, Age, Sex, Date and State of Collection Grasshopper Sparrow iAmmocIramus savannarum) — Male, adult, 10 March, Alabama: 13.0. Sharp-tailed Sparrow [ Ammospiza caudacutu) — Female, adult, 22 January, Alabama: 14.0. Seaside Sparrow i Ammospiza maritima) — Male, adult, 22 January, Alabama: 20.0; 22.0; 22.0. Female, adult, 22 January, Alabama: 19.0. Vesper Sparrow (Pooecetes gramineus) — Male, adult, 26 February, Alabama: 25.0. Slate-colored Junco (Junco hyemalis) — Male, immature, 4 January, Alabama: 17.5. Wbite-crowned Sparrow i Zonotrichia leucophrys) — Male, adult, 28 February, Alabama: 30.0 White-throated Sparrow i Zonotrichia albicollis) — Male, adult, 8 April, Alabama: 28.0. Female, adult, 17 March, Alabama: 25.0; 38.8; 41.5. Unsexed, adult, 12 January, Ala- bama: 29.4. Fox Sparrow (Passerella iliaca) — Male, adult, 12 January, Alabama: 38.8; 41.5. Male, adult, 27 December, Alabama: 42.0. Song Sparrow [Melospiza melodia) — Male, adult, 3 February, Alabama: 25.0. U.S. DEPARTMENT OF AGRICULTURE, AGRICULTURAL RESEARCH SERVICE, ENTO- MOLOGY RESEARCH DIVISION, OXFORD, NORTH CAROLINA AND ALABAMA DE- PARTMENT OF CONSERVATION, MONTGOMERY, ALABAMA. 22 SEPTEMBER 1965. FOODS OF THE BLACK-BELLIED TREE DUCK IN SOUTH TEXAS' Eric G. Bolen and Billy J. Forsyth The abundance and economic importance of many North American water- fowl have lead to comprehensive studies of their food habits ( see Cot- tam, 1939, Martin and Uhler, 1951, and others ( . Similar information for protected and less common species is often scattered and derived from in- frequent samples, and moreoften, entirely wanting. However, food habits data from a limited series of samples gain value when these stem from local populations of an uncommon species. Presented here are the results of food analyses from a restricted population of the Black-bellied Tree Duck (Dendrocygna autumnalis) nesting in South Texas. METHODS Tree ducks collected for food habits studies and other analyses (Bolen, 1964 ) were taken at Lake Corpus Christ! in Live Oak and San Patricio Counties, Texas. The data reported were obtained from 22 stomachs and 11 crops analysed in the following manner: The contents of the entire stomach, including grit, or crop were immersed in water to measure the total volume by displacement. The materials were next oven dried and separated. A visual estimate of volume by per cent of each item was made using a grid system; the relative volume in milliliters was then calculated from the total volume. Grit and food items were next weighed and filed in a reference collection. Data were kept on separate file cards for each stomach and crop studied. This proved an accurate yet rapid method for handling the materials (Forsyth, 1965). U.S. Standard Sieves were used to separate grit materials. Each size class was then weighed and this figure expressed as a percentage of the total sample from all stomachs. Both stomach and crop contents were used to compute the volumes of each food item. However, these data are separated into the larger categories of plant and animal foods (Table 1 ( for comparisons with other studies where foods were analysed from stomach or crop samples alone. Differences in the contents of these organs result from the retention of the harder animal parts in the stomach well after the softer plant materials have passed into the lower digestive tract; foods found in the crop are more likely retained without a selection favoring either plant or animal items. Computation of each food’s frequency of occurrence was based only on stomach contents. In this study all but 1 of tbe 22 birds collected were adults in fully matured plumage. Tbe remaining bird was a young-of-the-year capable of flight yet ^ C.ontribution No. 10.3, Rob & Bessie Welder Wildlife P’otindation, Sinton, Texas. 43 44 THE WILSO^ BULLETIN Marcli l'J67 Vol. 79. No. 1 Table 1 Pehckmage of Plant and Animal Piems Found in the Stomachs and Crops of Black-bellied Thee Ducks Type Stomachs (22) Crops (11) Total of food ml % ml % ml % Plant 56.7 86.8 134.7 94.4 191.4 92.0 Animal 8.6 13.2 8.0 5.6 16.6 8.0 Total 65.3 100.0 142.7 100.0 203.0 100.0 still in drab juvenal plumage. The food items in this bird were enough like those of adults collected during the same month ( September ) to he included in the tabulations. PLANT FOODS Plant foods made up 92 per cent of the diet. Of these, the cultivated grain, Sorghum vulgare. constituted nearly half of the total food volume (Table 2). Wild and cultivated strains of Bermudagrass iCynodon dactylon ) collectively ranked secondmost in volume. Seeds of cultivated Bermudagrass. while inseparable from the wild strain, are likely less important since this hybrid produces few inflorescences (Gould and Box, 1965). Tree ducks ingest both sorghum and Bermudagrass in large quantities, often to the point that the crop is distended and visible immediately after feeding. The incidence of corn ( Zea mays ) in our samples resulted from birds feeding in stockyards rather than feeding directly in cornfields. Corn is not a common field crop in South Texas. However, the importance of corn as a tree duck food no doubt increases elsewhere in the bird’s range where this crop is widely cultivated. Bent ( 1925 ) accordingly mentions that the Black- bellied Tree Duck has earned the name, “pato maizal,” or cornfield duck because of the depredation it supposedly inflicts on corn crops in Mexico. Two species of millet, Echinochloa colonum and E. crusgalli, were found. These constituted about 6 per cent of the total food volume. Both plants are often associated with Bermudagrass in moist pasture habitats; grazing tree ducks alternately strip seeds from the millets and Bermudagrass where these grasses are both available. Smartweeds, Polygonum lapathijolium and P. longistylum, together made up less than 1 per cent of the total food volume. At Lake Corpus Christi, shoreline beds of water stargrass ( Heteranthera liebmanni) are favored feeding and loafing places for Black-bellied Tree Ducks in late summer. Two growth forms of this plant are evident. One 45 Eric G Bolen and FOODS OF THE BLACK-BELLIED TREE DUCK Billy J. Forsyth occupies mudflats and lake margins in dense, carpet-like stands. Its aquatic counterpart exhibits longer stems and leaves and grows in deeper water. These differences are likely adaptive responses to changing water levels. Seeds of water stargrass (6 per cent of the total volume) presumably came from the shallow-water stands since these are more apt to flower than aquatic beds of the same plant. Moreover, Black-bellied Tree Ducks typically wade in shallow areas rather than venture into deeper water for food. Elsewhere, Martin and Uhler (1951) reported that water stargrass may become a noxious weed detrimental to other, more desirable plants; they considered it of slight importance as a waterfowl food. All plant foods found in either crops or stomachs consisted of seeds only. There was little or no suggestion of leaves, stems, or root systems in the samples. However, hand-reared tree ducks readily accept the leafy parts of common vegetables as food items. ANIMAL FOODS Earlier references to Black-bellied Tree Duck foods appear as observational data only (see Phillips, 1922; Bent, 1925; Kortright, 1942; Delacour, 1954; and Bolen et ah, 1964 ) . Only plant foods are mentioned in these reports. However, animal foods made up at least 8 per cent of our sample. Mollusks and insects were represented, both groups often occurred in volumes so small as to be immeasurable. A single gastropod species, Physa anatiua, was identified from crop materials; 16 individual snails of this species were found in the crop of a single bird. Only small, unidentifiable bits of shell were usually present in stomach contents. Thus, in Table 2, the mollusk foods are lumped without further classification. We believe, however, that these are gastropod forms, and probably Physa. Insects composed the balance of the animal food volume. About one-half of the insects, by volume, could not be identified. The remainder included the following orders and families: Hemiptera (unidentified immature forms), Neuroptera ( larva of Myrmeleontidae ) , Coleoptera ( Cicindelidae, Carabidae, and Tenebrionidae ) , and Diptera (larva of Stratiomyidae ) . A flour beetle, Tribolium castanatus, was identified from a crop filled with Bermudagrass seeds. Insects are undoubtedly taken, perhaps passively, by birds feeding in stands of water stargrass or when grazing in pastures. frequi:n€y of occurrenci: Plant foods occurred in all ( 100 per cent ) of the stomachs. 1’en ( I5.5 per cent ) stomachs contained some form of animal materials. The frequency of individual food items is shown in Table 2. Bermudagrass 46 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Table 2 Volume and Frequency of Food Fiems for the Black-bellied Tree Duck in South Texas. Saaifle size in farenthesis ; T = Trace Item Volume (ml) Occurrence — 22 stomachs Stomachs (22) Crops (11) Total % No. % Cynodon dactylon 13.2 48.0 61.2 29.5 10 45.5 Sorghum vii/gare 17.9 82.5 100.4 48.3 7 31.8 Echinochloa spp. 9.8 2.0 11.8 5.7 4 18.2 Polygonum spp. 0.6 - 0.6 0.2 6 27.3 Heteranthera Uebmanni 12.2 1.0 13.2 6.3 5 22.7 Zea Til ays 3.0 1.2 4.2 2.0 1 4.5 -Mollusca {Physa anatina) 2.3 8.0 10.3 5.0 8 36.4 Insecta 6.3 T 6.3 3.0 5 22.7 Total 65.3 142.7 208.0 100.0 - - and sorghum again showed prominence as tree duck foods in South Texas. Other plants appeared 18 to 27 per cent of the time. Corn, for reasons al- ready mentioned, was found in only 1 (4.5 per cent I of the 22 stomachs. Animal foods were found as often as most of the individual plant foods. Mollusks occurred in 36 per cent of the stomachs and insects in nearly 23 per cent. SEASONAL FOOD TRENDS The Black-bellied Tree Duck population near Lake Corpus Christi repre- sents an expansion of their northern range ( Bolen, et ah, 1964 ) . Here the birds arrive irregularly in March or April and remain in large flocks near cattle feedlots. They loaf on the shores of nearby farm ponds, but fly to the stockyards at dawn and dusk for food. No stomach collections were taken during this period for this reason. Instead, birds were collected fol- lowing their spring dispersal to the lake proper. The distribution of these collections was as follows: 5 birds taken in May, 6 in June, 4 each in July and August, and 3 in September. These are inadequate for steadfast con- clusions, but they indicated with field observations, a shifting trend in foods well geared to plant phenology (Table 3). Bermudagrass is the staple food in May. Stockyards receive further utiliza- tion but native grasses begin drawing flocks of tree duck to pastures near Lake Corpus Christi. In June, as the field crops ripen, sorghum enters the diet. By late June and early July the sorghum harvest is underway and field wastes lead to an abundance of this tree duck food. Stubble flights are initiated; the birds embark on a daily schedule to the grain fields that lasts into fall. Birds collected in July showed the most varied diet because Eric G B..ien an.i FOODS OF THE BLACK-BELLIED TREE DUCK Billy J. Forsyth 47 Table 3 Summary of Seasonal Food Trends for the Black-bellied Tree Duck in South Texas. Data Combined from Crop and Stomach Analyses (1963) and Field Observations (1962-1965) Month Major food Comment March and/or April Stock foods Arriving birds congregate at stockyards; foods May Bermudagrass exclusively grains until birds disperse Flocks graze in pastures stripping seed beads; June Sorghum some millets taken and some continued use of stockyards Grain harvest begins; birds start flights to fields July Sorghum & variety of native food plants Smartweeds, etc., but mainly sorghum August Sorghum & water stargrass Stubble flights continue; pairs with young September Sorghum & water broods in beds of water stargrass stargrass Stubble flights prominent in entire tree duck population, including flying young-of-the-year ; large groups loafing in water stargrass during mid-day hours; similar pattern continues into fall of the addition of smartweeds and the continued use of various grasses. Water stargrass is late in setting seed and accordingly showed a distinctive seasonal occurrence in the tree duck diet; it was found in birds taken during late August and September. No seasonal trend was shown in the occurrence of animal foods; these prevailed with equal frequency throughout the sampling period. GRIT Grit varied from 0.8 to 2.4 grams per stomach. The mean weight was 1.4 grams for the 22 stomachs analysed. Grit was of both opaque and translucent materials of considerable size variation (Table 4). Well over one-half of the grit, by weight, passed through a No. 10 U.S. Standard Sieve (less than 2000 microns). About 5 per cent was large enough to catch in a No. 4 sieve (4760 microns). Besides the mineral contents, 1 stomach contained 2 pieces of worn, smooth glass and another held a single No. 6 lead shot. SUMMARY The foods of the IBaek-hellied Tree Duck in South Texas were, }>y volume, 92 per cent plant materials. Of thes(*, sortrliurn and Bermudafirass predominated in both 48 THE WILSON BULLETIN Marrli 1967 Vol. 79, No. 1 Table Size and Weight Distribution of 30.5 22 Black-bellied Tree 4 Grams of Grit Duck Stomachs Materials from U. S. standard Mesh size Weight Per sieve number ( microns ) (g) Cent 4 4760 and larger 1.5 4.9 8 2380 4.3 14.1 10 2000 1.2 3.9 16 1190 11.8 38.7 20 840 6.4 21.0 - less than 840 5.3 17.4 Total 30.5 100.0 volume and percentage frequency. Other food plants included smartweeds, millets, water stargrass, and a single incidence of corn. Plant foods consisted only of seeds and did not include vegetative structures. Animal foods (8 per cent by volume) consisted of insects and mollusks. Each of these occurred about as often as the major plant foods. The snail, Physa anatina, seemed singularly important. Tree duck food habits change with the advance of the growing season. There is an initial period of “artificial” feeding on stockyard grains after the spring migration. This changes to Bermudagrass in May, then to sorghum in mid-summer. Daily stubble flights to sorghum fields continue into fall hut the late summer diet is supplemented by water stargrass. Grit from tree duck stomachs averaged 1.4 grams per bird and showed considerable size variation. ACKNOWLEDGMENTS We are indebted to both the Rob and Bessie Welder Wildlife Foundation and the Frank M. Chapman Memorial Fund of the American Museum of Natural History for support of this study. Clarence Cottam, W. Caleb Glazener, Jessop B. Low, and Franklin C. Henze made many contributions. The following authorities kindly identified or con- firmed our identifications of the items indicated: Leland Chandler and Willard Whit- comb (insects), Anne W. Speers (mollusks), Francis M. Uhler (seeds), and Arthur H. Holmgren and Fred B. Jones (plant taxonomy). The Soil Conservation Service provided the use of soil sieves for grit measurements. LITERATURE CITED Bent, A. C. 1925 Life histories of North American wild fowl. Part 11. JJ.S. Natl. Mas. Bull. 130. Bolen, E. G. 1964 Weights and linear measurements of Black-bellied Tree Ducks. Texas Jour. Sci., 16:257-260. Bolen, E. G., B. McDaniel, and C. Cottam 1964 Natural history of the Black-bellied Tree Duck in southern Texas. South- western Naturalist, 9:78-88. But L?orrvtr" foods of the BLACK-BELLIED TREE DUCK 49 COTTAM, C. 1939 Food habits of North American diving ducks. Tech. Bull. 643, U.S. Dept. Agr., Washington, D.C. Delacour, J. 1954 The waterfowl of the world. Vol. I. Country Life, Ltd., London. Forsyth, B. J. 1965 December food habits of the Mallard (Anas platyrhynchos) in the Grand prairie of Arkansas. Proc. Arkansas Acad. Sci., 19:74-78. Gould, F., and T. W. Box 1965 Grasses of the Texas Coastal Bend. Texas A&M Univ. Press, College Station, Texas. Kortrigiit, F. H. 1942 The ducks, geese, and swans of North America. The Stackpole Co., Har- risburg, Pa. Martin, A. C., and F. M. Uhler 1951 Food of game ducks in the United States and Canada. Research Report 30, U.S. Fish & Wildl. Serv., Washington, D.C. Phillips, J. C. 1922 A natural history of the ducks. Vol. I. Houghton Mifflin Co., Boston, Mass. ROB & BESSIE WELDER WILDLIFE FOUNDATION, SINTON, TEXAS ( PRESENT ADDRESS: DEPARTMENT OF AGRONOMY AND RANGE MANAGEMENT, TEXAS TECHNOLOGI- CAL COLLEGE, LUBBOCK, TEXAS (BOLEN) AND DEPARTMENT OF ZOOLOGY, UNI- VERSITY OF ARKANSAS, FAYETTEVILLE, ARKANSAS (FORSYTH) ), 11 JANUARY 1966. WIND DRIFT, LEADING LINES, AND DIURNAL MIGRATION Helmut C. Mueller and Daniel D, Berger PERSONAL discussions with a number of North American students of bird migration indicate that there is considerable confusion and misunder- standing of the concepts of wind drift and leading lines. Recently, Murray (1964) published a review in which he refutes wind drift, at least insofar as it applies to the migration of Sharp-shinned Hawks {Accipiter striatus) in the northeastern United States. The present review is an attempt to: (1) define and show the implications of theories of wind drift and leading lines, in particular as to how they affect hawk migration; (2) discuss some of the evidence for the theories; and (3) show that the theories are consistent with the observations of hawk migration in the northeastern United States and show that Murray’s (1964) hypothesis is inadequate. This paper is in part an attempt to extract generalizations from the available evidence. How- ever, generalizations are rarely valid for all species and situations; and, further, generalizations based on little data are often shown to be unwarranted when more evidence becomes available. WIND DRIFT: DEFINITION Trowbridge ( 1895, 1902 ) may have been the first to discuss explicitly the influence of wind drift on bird migration. The theory received further analysis and support from Baxter and Rintoul (1918). There are a great number of recent works concerned with drift, and we slight many excellent papers by mentioning only Rudebeck (1950) and Williamson (1955) as examples. Lack and Williamson (1959 ) have defined drift as the “Displace- ment of a migrant from its normal route by the wind, . . .” We do not like this definition because of the implications of the adjective “normal.” It is our belief that, at least for many species of migrants, drift is a normal phenomenon. We maintain that the route taken by a bird is the result of: (1) the “standard direction” (Thomson, 1953) of migratory flight; (2) wind drift, which may influence some birds more than others; and (3) at least in the case of many diurnal migrants, the topography. Data from banded birds suggest that most birds return to the same summer area year after year (Nice, 1937; Werth, 1947; Austin, 1949; Lohrl, 1959) and also that many birds return to areas in which they have previously spent the winter (Wharton, 1941; Petersen, 1953; Schwartz, 1963; Mewaldt, 1964). We know of no data, except possibly those from some species of waterfowl ( see e.g. Hochbaum, 1955, p. 110-111), which offer good evidence for the hypothesis that an individual bird follows the identical migratory route year after year. We have banded over 50,000 birds at the Cedar Grove Ornithologi- 50 Mueller and Berger DIURNAL MIGRATION 51 cal Station and have recaptured only three migrants in a subsequent season. Thus it appears that the end points of the migration are fixed and that the path pursued by a bird between these two points varies considerably from year to year. This idea was stated explicitly by Baxter and Rintoul 11918) and gains further support from current studies of the recoveries of banded birds ( Mueller and Berger, in press, a,b ) . Since we believe that the route of a migratory bird normally is determined in part by drift, we prefer to define drift simply as the displacement of a bird due to wind. LEADING LINES: DEFINITION AND CHARACTERISTICS Effects of the underlying terrain on the flight of diurnal migrants have been noted by many observers. For the moment we shall restrict our atten- tion to effects of the terrain on the direction of flight. Land birds apparently are reluctant to fly out over water and sea birds appear to be reluctant to fly in over land (van Dobben, 1953; Svardson, 1953). Similarly, birds of open country seem to be reluctant to fly out over wooded areas and forest birds apparently are reluctant to fly out over treeless terrain ( Deelder and Tinbergen, 1947 ; Malmberg, 1955 ) . An isolated area of suitable habitat can attract and change the course of a diurnal migrant, acting as a “leading point” (Malmberg, 1955). Far more important and interesting is the phenomenon of the “leading line.” The leading line or Leitlinie was first defined by Geyr (1929). In the process of translation into Dutch, English, and other languages the meaning and definition of Leitlinie was altered. Some translations, such as the “diver- sion line” of Lack and Williamson ( 1959), have misleading connotations and cannot be applied readily to all types of leading lines. Geyr ( 1963 ) has authorized the following translation and definition: “Leading lines are topographical features, usually long and narrow, with characteristics that induce migrating birds to follow them. The birds are influenced by these lines in choosing their direction of flight, being so to speak led by them.” The most common type of leading line is a boundary between suitable and unsuitable habitat. The most striking example of this is a coastline, where the aversion that land birds have for water results in a concentration of migrants along the coast ( Rudebeck, 1950; Mueller and Berger, 1961). Habitat boundaries, such as the edge between a forest and an open field or marsh, also act as leading lines (Geyr, 1963; van Dobben, 1955; Allen and Peterson, 1936 ) . Another type of leading line is that which provides conditions which expedite the passage of the birds. An outstanding example of this is the mountain ridge, which deflects the horizontal wind and provides updrafts for soaring birds (Robbins, 1956; Ulfstrand, 1960). The abundance of food 52 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 along coasts and rivers may aid the passage of migrants that feed while migrating (von Westernhagen, 1957; Hurrel, 19551. Lastly, there appear to be leading lines which do not border unfavorable habitat or offer any obvious advantage to the migrant except that they ap- proximately parallel the flight direction of the bird. Examples of this include river valleys ( Svardson, 1953 ) and dunes and dykes ( van Dobben, 1953 1 . Thus, there is apparently a tendency for birds to follow^ leading lines, quite apart from the aversion of the bird to hostile habitat, or the attraction of up- drafts, food abundance, or other conditions which might aid migration. Land migrants coming inland from flight over bodies of water have been ob- served to turn and fly along the coast (van Dobben, 1953; Lack, 1962; Wil- liamson, 1962; Mueller and Berger, in preparation ) . Leading lines may help a bird orient during migration and may help it avoid excessive wind drift (Svardson, 1953; van Dobben, 1955; Nisbet, 1957; Williamson, 1962). EFFECTIVENESS OF LEADING LINES A bird is, of course, not compelled to follow a leading line; it can cross, or turn back from, the line. The effectiveness of a leading line varies; some of the variables involved are listed below: ( 1 ) The linearity of the leading line. Straight, well defined, and un- interrupted lines are most effective. An irregular and dissected coast, for example, leads few birds while a straight coastline with little variance in habitat type is highly effective ( Rudebeck, 1950 ) . ( 2 I The length of the leading line. The longer the line, the greater the number of birds that might encounter and follow the line. ( 3 ) The angle formed between the leading line and the direction of flight of the bird. The greater the angle, the less the tendency for the bird to follow the line (Deelder, 1949; Svardson, 1953). ( 4 ) The prominence of the leading line. The coast of the ocean is obviously more effective than the shore of a narrow embayment; an abrupt, high ridge is more effective than a low, gentle slope. ( 5 ) The bird’s motivation to migrate. The higher the migratory impulse, the lower the attractiveness of the leading line (Rudebeck, 1950; Thomson, 1953). (6) The geographic location in relation to the bird’s origin and destina- tion. Birds seem to react more strongly to the coastline in Norway, where sea crossing is undesirable, than in Holland, where sea crossing is a normal part of migration ( Nisbet, 1957 ) . (^7) Wind direction. Chaffinches {Fririgilla coelebs) cross the Dutch Mueller and Berger DIURNAL MIGRATION 53 coast and head out over the English Channel in greater numbers in a tail- wind than in a headwind ( Deelder, 1949 ) . The opposite is true for hawks crossing a strait or bay ( Rudebeck, 1950; Stone, 1937). (8) The time of day. Hawks appear to be less willing to cross water later in the day than they are early in the morning ( Rudebeck, 1950 ) . (9) The height of flight. The greater the altitude of flight, the less the bird is influeneed by leading lines ( Deelder and Tinbergen, 1947 ; Rudebeck, 1950 ) . Chaffinches react to the Dutch coastline when it is up to 5 km away and when its surface subtends an angle of less than 50' ( Deelder and Tinbergen, 1947). Rudebeck (1950) has observed hawks flying parallel to the Swedish coast, but some distance from it. Birds might thus follow, or parallel, a leading line at quite some distance from the line, and an observer on the line might be unaware of such a parallel flight. HEIGHT OF FLIGHT The height of flight of diurnal migrants influences not only their reaction to leading lines but also their probability of being observed. Some of the factors which influence height of flight are listed below: (1) Wind direction. Birds fly higher in a tailwind and lower in a head- wind or crosswind (Trowbridge, 1902; Deelder and Tinbergen, 1947; Rude- beck, 1950). (2) Wind speed. Birds fly lower in strong winds (Deelder and Tinbergen, 1947 ) . (3) The underlying terrain. Sea birds fly higher over land than over the sea, land birds fly higher over the sea than over land ( Svardson, 1953 ). Forest birds fly higher over open, than over wooded, terrain (Deelder and Tinbergen, 1947 ) . Hawks fly much higher over cities than over wooded terrain (Trowbridge, 1902). (4) Leading lines. Birds flying along a leading line usually fly quite low ( Deelder and Tinbergen, 1947 ) . Hawks have been observed to descend to lower altitudes when they encounter a coast ( Allen and Peterson, 1936 ) . These observations suggest that the leading line might induce lower flight. (5) Visibility. Chaffinches fly lower in fog and heavy rain (Deelder and Tinbergen, 19 17 ) . EVIDENCE OF DRIFT Most of the data in support of the theory of wind drift provide indirect evidence; it is exceedingly difficult to observe drift in progress. Before one can evaluate a direct observation which seems to indicate drift one must be certain of the following: (1) that the bird was actually migrating. (2) the 54 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Standard migratory direction of the bird. 1 3 ) that the bird was not being influenced by topography. These conditions are almost impossible to meet. hether or not a bird is actually migrating can be determined only sub- jectively no matter how well the migratory habits of the species observed are known, and no matter how experienced the observer. The standard migratory direction can only be inferred from the distribution of band recoveries or from observations of birds in flight, both of which are influenced by drift and topography. Attempts to determine the standard direction by experimental means may produce misleading results l see Kramer, 1950: Matthews. 1961 1 . Absolutely featureless terrain does not exist, and the possibility that a bird is being influenced by topography cannot be dismissed completely. ith the above difficulties in mind, we submit below some observations which might be interpreted as offering some direct evidence of drift. Over the past several years we have collected 14 observations of hawks flying over relatively featureless terrain, away from obvious leading lines, and during the time of year when the species is normally migrating. Each of the hawks moved in a relatively constant direction for a considerable distance and was thought to be migrating. The 14 observations were of the following species and individuals: three Marsh Hawks [Circus cyaneus), seven Red-tailed Hawks \Buteo jamaicensis ) . four Rough-legged Hawks [Buteo lagopus). and more than 500 Broad-winged Hawks \ Buteo platypterus) . Two of the Red- tailed Hawks were flying south on a calm autumn day. The Broad-winged Hawks were moving southward on an autumn day in a light northerly wind. Of the remaining individual observations, four birds were moving downwind in an inappropriate direction ( at least 90° from the “expected direction" of north in spring, south in autumn I . Another three birds were moving upwind in an inappropriate direction, and two birds were moving upwind in the appropriate direction. Only three birds, two low flying Marsh Hawks and one low flying Rough-legged Hawk, were observed to quarter the wind. Each of these three birds was moving in essentially the appropriate direction. The above observations suggest that some hawks fly up- or downwind. Maximum drift can occur if birds fly downwind. Considerable displacement can also occur if the birds fly into the wind. Further observations of migration away from leading lines are needed. Rainey ( 1960 1 analyzed photographically the flight of two European Storks \Ciconia ciconia\ over a brief interval of time and concluded that the birds were being drifted by the wind. However, the date and location of observation were not given, and it is impossible to state whether or not the birds were migrating. Lack (1960) concluded that his radar observations offered evidence for the wind drift of migrating birds. He usually found no Mueller and Berger DIURNAL MIGRATION oo differences in the flight directions over land and over sea of both nocturnal and diurnal migrants. WIND DRIFT THEORY The lack of good, direct evidence does not prevent the elucidation of the mechanisms of drift by theoretical means. For purposes of discussion we can consider drift to be of three types: (1) Downwind drift. The birds simply fly downwind. This mode of flight has been suggested by Williamson (1955) and, somewhat differently, by Mueller and Berger (1961). (2) Free drift. The bird flies through the air in the standard migratory direction. The flight path, or track, relative to the earth is a resultant of the standard migra- tory direction and the wind. Lack ( 1960 ) presents evidence from radar ob- servations which suggests that this type of drift is common over the North Sea. ( 3 I Compensated drift. The bird attempts to compensate partially for drift by altering its direction of flight through the air so that its path relative to the earth more nearly approximates the standard migratory direction. This presumably would be very difficult without reference to landmarks. Leading lines and a low altitude of flight would aid attempts at compensation. Flight at high altitudes and with a paucity of suitable landmarks would make com- pensation difficult. Lack ( 1960 ) , in writing of the diurnal migrations of Starlings (Sturnus vulgaris), concluded with: “Evidently, however, they can correct for drift over the land only when flying low, since radar observa tions in 1959 suggested that drift normally was as extensive over the land as over the sea.” Birds utilizing updrafts in flight are extremely subject to drift. In the presence of a horizontal wind, with its resulting shear, thermal updrafts are tilted downwind. Birds which soar in circles, such as hawks of the genus Biiteo, are subject to considerable drift in the relatively slow ascent in an updraft. The direction taken in the rapid glide when the bird leaves the updraft varies with the wind direction and the orientation of leading lines. The mean flight direction resulting from several ascents and descents is not easy to discern. The flight direction in one part of such a flight pattern often is very different from the mean flight direction. More than a few students of hawk migration have been misled by this phenomenon. A detailed discus- sion of the action of wind drift on birds that soar in circles can be found in Rudebeck (1950). At higher horizontal wind velocities birds no longer soar in circles. In an earlier paper ( Mueller and Berger, 1961 ) we suggested that, at higher wind velocities, updrafts form into longitudinal strip-like cells of updrafts and downdrafts, oriented up- and downwind (see also oodcock. 1912). Lnder these conditions it is considerably easier for a bird to fly up- or downwind. 56 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 than it would be for it to fly across the wind direction, and thus presumably the effects of wind drift would be increased. Space prohibits the citation of all of the papers utilizing wind drift in the analysis of migration data. The indirect evidence for the theory of wind drift is considerable. There appears to be only one attempt at refutation of the theory, that of Murray (1964), an analysis of which follows. WIND DRIFT AND SHARP-SHINNED HAWK MIGRATION ALONG THE NORTHEASTERN COAST OF THE UNITED STATES In his review of studies of Sharp-shinned Hawk migration along the Atlantic coast, Murray (1964) states that: “Trowbridge (1895, 1902), Stone (1922), and Allen and Peterson (1936) hypothesized on the basis of their observations that: (1) Sharp-shinned Hawks normally migrate inland; (2) northwesterly winds drift (“lateral displacement” of Lack and William- son, 1959) the hawks to the coast; and (3) once at the coast they continue along the coast.” Our interpretation of the works of Trowbridge, Stone, and Allen and Peterson differs from that of Murray. We find that: (1) only Allen and Peterson mention the concept of a normal inland route, and it is not essential to our concept of wind drift. ( 2 ) Although Stone ( 1922 ) sug- gests the possibility of hawks flying along the coast, he apparently abandoned this idea in a later publication (Stone, 1937). Only Trowbridge (1895, 1902 ) directly mentions hawks following the coast. We quote from Trow- bridge ( 1902 ) : “They then turn westward and follow the Connecticut shore until they have reached New York and New Jersey, where they gradually separate and pass on southward.” It would seem that Trowbridge, Stone, and Allen and Peterson were aware that hawks did not follow the coasts exactly and invariably. Murray argued that the above hypotheses were not supported by the data and offered “an alternative hypothesis that explains all of the observations.” Murray states his hypothesis in this form: “The published evidence sup- ports the view that Sharp-shinned Hawk migration proceeds on a broad front in a generally soutbwestward direction ( in the northeastern United States ) at an altitude that makes observation difficult, and that the observed ‘con- centrations’ or ‘flights’ are manifestations of the diversion line phenomenon.” There is evidence that Sharp-shinned Hawks often migrate at a considerable height (Allen and Peterson, 1936), but the remaining components of Mur- ray’s hypothesis are unsupported by published evidence. The “diversion line phenomenon” is simply a variant of the leading line, in which only a portion of the birds follow the line, the remainder crossing the line. Murray’s hy- pothesis is apparently based on the observations of a number of Dutch workers on the flight behavior of the Chaffinch and summarized by van Dobben (1953). Mueller anil Berger DIURNAL MIGRATION 57 The “diversion line ’ for hawks at Cape May differs from the Chaffinch- diversion lines in Holland in the following important characteristics: (1) It is very short; (2) Birds decrease rather than increase in numbers as one proceeds “downstream” along the line, in fact the numbers of birds appear to be at a maximum at the beginning of the diversion line; (3) The angle between the presumed migratory direction and the diversion line exceeds 90°, or, in other words, the diverted birds appear to be flying in the wrong direction along the line; (4) More birds fly out over, and across the water barrier in a head wind and more birds are “diverted” in a tail wind. These differences suggest that the concentration of hawks at the tip of Cape May is due to something other than the Murray-van Dobben model of the diversion line. Murray postulates a broad front movement, apparently not concentrated by wind drift. Thus, we would expect similar numbers of hawks to occur over the entire northeastern United States. Local “concentrations” are thus merely the result of a partial diversion of the stream of migrants passing overhead. If we know the length of the “diversion line” we should be able to get a partial estimate of the numbers of birds passing overhead, and, since it is a broad-front movement, an estimate of the entire population. At Cape May, an all-autumn count taken in 1935 largely within one mile of the beginning of the “diversion line” yielded a total of 8,026 Sharp-shinned Hawks (Allen and Peterson, 1936). Probably not all of the hawks passing Cape May were counted, and, as Murray indicates, only a portion were diverted. However, let us conservatively estimate that all of the Sharp-shinned Hawks that passed over the one mile “front” at Cape May were counted in the autumn of 1935. The available information on the breeding distribution of the Sharp-shinned Hawk, and the distribution of suitable habitat, offer no reasons to believe that these hawks are more common to the northeast of Cape May than they are anywhere else in northern North America. The continent is about 2,500 miles wide. We would thus expect the North Ameri- can Sharp-shinned Hawk population to be at least 20 million birds. Peterson (1948, p. 65 ) has estimated the total population of birds of the continent north of Mexico to number about 12 to 20 billion. It seems unlikely that one out of every 600 to 1,000 birds in North America is a Sharp-shinned Hawk. Indeed, it seems unlikely that one out of every 6,000 to 10,000 birds in North America is a Sharp-shinned Hawk. It is more reasonable to believe that the hawk observations at Cape May are of concentrations of birds, and that on the average, seen and unseen, more Sharp-shinned Hawks fly over Cape May than over most other localities. We present below our tentative analysis of the migrations of Sharp-shinned Hawks along the northeastern coast of the United States, based on the con- 58 THE WILSON BULLETIN March 1967 Vol. 79. No. 1 cepts of leading line and wind drift. Concentrated flights of hawks occur only in a few localities along the Atlantic coast because the frequent embay- ments, marshes, irregularities, urban, and industrial areas make most of the coast a poor leading line. Both Cape May and Cape Charles are at the southern tips of huge, gradually narrowing peninsulas. The tapering forms of the Delaware-Maryland-Virginia peninsula and the New Jersey peninsula tend to funnel southbound, water-shy, diurnal migrants, in spite of the ab- sence of good leading lines along the coasts. Concentrations of Sharp-shinned Hawks are not obvious north of Cape May and Cape Charles because ( 1 1 the frequent marshes, embayments, and tidal areas are unsuitable habitat for the hawks and they fly relatively high, and ( 2 I the irregular borders between land, marsh, water, etc., do not form good leading lines, and hawks arriving at the coast are continually being dispersed inland. Allen and Peterson ( 1936 ) have shown that the hawks arrive at Cape May Point at considerable altitude, and that the flights north along Delaware Bay are rapidly dispersed because the hawks avoid crossing marshes and tidal creeks. The tendency for a hawk to attempt or avoid a given water crossing is affected by a number of factors, including the bird’s motivation to migrate, the time of day, and, perhaps most importantly, the wind direction. Allen and Peterson ( 1936 ) found that, at Cape May, Sharp-shinned Hawks crossed Delaware Bay when the wind was blowing from somewhere between ENE and SW and avoided the water crossing on NW to NE winds. Birds crossing Delaware Bay from Cape May often flew very high, “usually from 500 feet to the limit of vision” (Allen and Peterson, 1936). Birds avoiding the crossing also arrived at Cape May Point at a rather high altitude, dropped to a lower altitude, and moved north along the bay side of the cape ( Allen and Peterson, 1936 ) . Usually, the greatest numbers of hawks were seen at Cape May on northwesterly winds (Allen and Peterson, 1936; Stone, 1922, 1937 ) . Good flights often occurred on southerly winds but, at least in 1935, these invariably occurred on days immediately following days of north- westerly winds. This suggests that essentially all of the major flights (except- ing only two, which occurred on northerly winds ) recorded by Allen and Peterson in 1935 were correlated with northwesternly winds. We believe that this correlation can be reasonably well explained by our version of the con- cept of wind drift. Stone ( 1922, 1937 I also found that hawk flights at Cape May were correlated with northwesterly winds, indicating that the data of Allen and Peterson for 1935 were not peculiar. Rusling ( 1937 ) found that the greatest flights of Sharp-shinned Hawks at Cape Charles, Virginia, in the autumn of 1936 occurred on northeasterly winds, and only small flights occurred on northwesterly winds. Murray (196T) considered Rusling’s (1937) evidence and conclusions an excellent Mueller and Berger DIURNAL MIGRATION 59 Hawk Flights Table 1 ON THE Mid-Atlantic Coast in 1936 Date Cape May Cape Charles Hoope r Island Rank Hawks Rank Hawks Rank Hawks 25 Sept. N-NE 1 300 6 363 1 800 13 Oct. NE-ESE 2 174 9 246 9 75 29 Sept. NE-ENE 3 150 10 177 - Few 2 Oct. N-NE 4 140 1 1,177 - 2 11 Sept. Var. 5 120 - * - * 19 Sept. NW 6 no - =:= - * 26 Sept. E-NE 7 100 5 418 3 700 10 Sept. NE 8 100 - * - 5 Nov. N 9 90 - 24 - 0 13 Sept. N 10 90 - * - * 4 Oct. ENE - 30 2 865 - 2 5 Oct. ENE - 18 3 714 - 0 3 Oct. NE - 80 4 612 - 30 1 Oct. W-N - 8 7 359 - 0 14 Oct. E - 16 8 322 - 14 24 Oct. NE-N - 70 - 160 2 800 31 Oct. NW - 5 - 4 4 600 21 Sept. NW-N - 20 - 5 300 10 Oct. SW-W - 0 - 0 6 200 1 Nov. sw - 0 - 1 7 125 9 Nov. NE - 3 - 9 8 100 17 Oct. w - 0 - 6 10 75 12 Oct. NW - 30 - 134 - 0 18 Oct. NW - 40 - 98 - 40 30 Oct. NW - 0 - 5 - 50 * No data available. The data in this table are from Rusling (1937). argument against wind drift, particularly when compared with observations from Cape May and Hooper Island, where hawks are known to occur pre- dominately on northwesterly winds. However, in the autumn of 1936, six of the ten largest flights of Sharp-shinned Hawks at Cape May and five of the ten largest flights at Hooper Island occurred on days with northeasterly winds (Table 1 ) . The fact that nine of the ten largest flights at Cape Charles occurred on northeasterly winds is not remarkable when compared with the above. At least the three greatest counts of Sharp-shinned Hawks for 1936 occurred on northeasterly winds in all three of the above localities (Table 1 I . It is remarkable that the highest counts of Sharp-shinned Hawks at Hooper Island and Cape May occurred on northeasterly winds rather than, as in previous years, on northwesterly winds. It is further interesting that only 2,269 Sharp-shinned Hawks were seen at Cape May in 1936 ( Rusling. 60 THE WILSON BULLETIN Maich 1967 Vol. 79, No. 1 1937), as compared with 8,206 in 1935, 5,675 in 1932, and 10,000 in 1931 (Allen and Peterson, 1936). Strong northwesterly winds and clear skies prevailed on only three days during September and October 1936 at Cape Charles ( Rusling, 1937 ). These conditions usually produce great numbers of hawks at Cape May and, presumably, at Hooper Island ( Allen and Peter- son, 1936 ) . On all of these days relatively few Sharp-shinned Hawks were seen at Cape May, Hooper Island, and Cape Charles, but greater numbers were seen at Cape Charles than at the other two localities on two of the three occasions (Table 1). In all, 1936 seems to have been a very unusual autumn for hawk migration along the mid-Atlantic coast of the United States. It would be interesting to see the characteristics of the Sharp-shinned Hawk migration at Cape Charles in a more usual year. Because of the configurations of the peninsulas, we would expect concen- trations of hawks at Cape May and Cape Charles in autumn if three con- ditions prevail: (1) reasonable numbers of hawks exist on, or arrive on. the New Jersey and Delaware-Maryland-Virginia peninsulas, (2) the birds migrate in some southerly direction, and ( 3 ) the birds exhibit some reluctance to cross bodies of water. We have previously discussed the third factor and the second safely can be assumed to occur. The first factor, however, can be analyzed only indirectly. The interaction of wind and leading lines in affecting the flight paths of hawks in the areas north of the New Jersey and Delaware-Maryland-Virginia peninsulas undoubtedly plays a major role in determining the abundance of hawks on the peninsulas. The strong leading lines provided by the Appalachian ridges lie but a short distance to the west of the Atlantic coast; and, farther to the north, the Great Lakes and the Gulf of St. Lawrence probably affect the flight paths of hawks. The frequent embayments on the coast and gaps in the ridges of the Appalachians add further complications. More observations of hawk migration at localities north and west of the coastal concentration points are needed before all questions can be answered. However, it is interesting to note that 4,611 Sharp-shinned Hawks, or 67 per cent of the total observed at Cape Charles, were counted in the two periods between 1 and 5 October, inclusive, and 12-15 October, inclusive. Both of these periods began with, or were pre- ceded by, at least one day of westerly winds over the entire region ( Rusling, 1937 ) . We believe that this suggests that wind drift may have been a factor in bringing hawks to the Delaware-Maryland-Virginia peninsula, and, once there, they continued southward to Cape Charles, producing concentrations at the cape for several subsequent days. In addition to the ahov^e, we would expect differences in the flights at Cape May and Cape Charles because ( 1 ) the New Jersey peninsula has a relatively broad base whereas the Delaware-Maryland-Virginia peninsula has a rela- Mueller and Berger DIURNAL MIGRATION 61 lively narrow connection with the mainland, (2) Chesapeake Bay is longer and generally wider than Delaware Bay, and ( 3 ) Cape Charles is about four times as long as Cape May and is extremely narrow at several points con- siderable distances from the tip. In conclusion, we fail to see how Murray (1964) has produced any evi- dence which can be used to argue that wind drift is not a factor in producing concentrations of Sharp-shinned Hawks at selected points on the coast of the northeastern United States. The alternative hypothesis proposed by Murray is unsupported by, and inconsistent with, the available evidence. SUMMARY This paper attempts to: (1) define the concepts of wind drift and leading lines, (2) present the characteristics of each of these phenomena, (3) elucidate the various factors influencing wind drift and leading line behavior, and (4) document the above with a brief review of the literature of migration. In addition, the hypothesis of Murray (1964) is critically evaluated as an alternative to wind drift theory and rejected as being in- consistent with available information. ACKNOWLEDGMENTS This paper began as the discussion section of an early draft of a research report on Sharp-shinned Hawk migration at Cedar Grove, Wisconsin (Mueller and Berger, in press, b). Financial support for the latter study was provided by the National Science Foundation (Grant GB-175). We are indebted to Professor John T. Emlen for advice and assistance in various aspects of the study. LITERATURE CITED Allen, R. P., and R. T. Peterson 1936 The hawk migrations at Cape May Point, New Jersey. Auk, 53:393-404. Austin, 0. L. 1949 Site tenacity, a behaviour trait of the Common Tern {Sterna hirundo Linn.) Bird-Banding, 20:1-39. Baxter, E. V., and L. J. Rintoul 1918 The birds of the Isle of May: a migration study. Ibis, 6, ser. 10:247-287. Deelder, C. L. 1949 On the autumn migration of the Scandinavian Chaffinch, (Fringilla c. coelebs L.) . 4 rdcff, 37:1-88. Deelder, C. L., and L. Tinbergen 1947 Waarnemingen over de vlieghoogte van trekkende Vinken, Fringilla coelebs L., en Spreeuwen, Sturnus vulgaris L. Ardea, 35:45-78. Dobben, W. H. van 1953 Migration in the Netherlands. Ibis, 95:212-234. 1955 Nature and strength of the attraction exerted by leading lines. Acta XI Congr. Internatl. Ornith. Rr/.se/: 165-1 66. GeYER von ScilWEl’I’ENBURC, H. FrIEII. 1929 Zugstrassen-Leitlinien. J. Ornith., Frgdnzungsband 11:17 32. 1963 Zur Terrninologie und Theorie der Leitlinie. J. Ornith., 104:191-204. 62 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Hochbaum, H. a 1955 Travels and traditions of waterfowl. U. Minnesota Press, Minneapolis. Hukrel, H. G. 1955 Simultaneous migration watches for Swifts in the British Isles. Acta XI Congr. Internatl. Ornith. Basel :640~6i2. Kramer, G. 1950 Weitere Analyse der Faktoren, welche die Zugaktivitat des gekafigten Vogels orientieren. Naturwiss., 37:377-388. Lack, D. 1960 Migration across the North Sea studied by radar. Part 2. The spring de- parture 1956-59. Ibis, 102:26-57. 1962 Radar evidenee on migratory orientation. Brit. Birds, 55:139-158. Lack, D., and K. Williamson 1959 Bird-migration terms. 76/5,101:255-256. Lohrl, H. 1959 Zur Frage des Zeitpunktes einer Pragung auf die Heimatregion beim Halsbandschnapper i Ficedula alhicollis) . J. Ornith., 100:132-140. Malmberg, T. 1955 Topographical concentration of flight lines. Acta XI Congr. Internatl. Ornith. fee/: 161-164. Matthews, G. V. T. 1961 ‘Nonsense’ orientation in Mallard and its relation to experiments in bird navigation. Ibis, 103a :21 1-230. Mewaldt, L. R. 1%4 California sparrows return from displacement to Maryland. Science, 146: 941-942. Mueller, H. C., and D. D. Berger 1961 Weather and fall migration of hawks at Cedar Grove, Wisconsin. Wilson Bull., 73:171-192. in press, a. “Navigation” of hawks: evidence from spring migration observations and band recoveries. in press, b. Migration of Sharp-shinned Hawks: analysis of data from Cedar Grove, Wisconsin. in preparation. Analysis of concentrations of nocturnal migrants along a coastline. Murray, B. G., Jr. 1964 A review of Sharp-shinned Hawk migration along the northeastern coast of the United States. Wilson Bull., 76:257-264. Nice, M. M. 1937 Studies in the life history of the Song Sparrow. I. Trans. Linnaean Soc. New York, 4:1-247. Nisbet, I. C. T. 1957 Passerine migration in South Scandinavia in the autumn of 1954. Ibis, 99: 228-268. Petersen, E. 1953 Orienteringsforspg med Haettemage i Larus r. ridibundus L. ) og Stormmage iLarus c. canus L. ) vinterkvarteret. Dansk Ornithol. Forenings Tidsskrijt, 47:153-178. Peterson, R. T. 1948 Birds over America. Dodd, Mead, New ^ork. Mueller and Berger DIURNAL MIGRATION 63 Rainey, R. C. I960 Applications of theoretical models to the study of flight-behavior in locusts and birds. Symposia Soc. for Expl. Biol., XIV: 122-139. Robbins, C. S. 1956 Hawk watch. Atlantic Naturalist, 11:208-217. Rudebeck, G. 1950 Studies on bird migration. V ar Fagelvdrld, Supplementum I. Rusling, W. J. 1937 The study of the habits of diurnal migrants, as related to weather and land masses during the fall migration on the Atlantic coast, with particular reference to the hawk flights of the Cape Charles (Virginia) region. Unpub- lished manuscript in the library of the National Audubon Society, New York. SCIIM^ABTZ, P. 1963 Orientation experiments with Northern Waterthrushes wintering in Venezuela. Proc. XIII Internatl. Ornith. Congr. 481-484. Stone, W. 1922 Hawk flights at Cape May Point, N. J. Auk, 39:567-568. 1937 Bird studies at old Cape May, Vol. 1. Delaware Valley Ornith. Club, Acad. Nat. Sci. Philadelphia. SVABDSON, G. 1953 Visible migration within Fenno-scandia. Ibis, 95:181-211. Thomson, Sir A. L. 1953 The study of the visible migration of birds. Ibis, 95:165-180. Tbowbridge, C. C. 1895 Hawk flights in Connecticut. Auk, 12:259-270. 1902 The relation of wind to bird migration. Amer. Nat., 36:735-753. Ulfstrand, S. 1%0 Migration of African kites Milvus migrans ( Bodd. ) — M. aegyptius Sharpe & Bouvier, and Wahlberg’s Eagles Aquila wahlbergi Sund., at Lake Tanganyika. Kungl. Fysiografiska Sdllskapets I Lund Fdrhandlingar, 30:31-39. Wertii, I. 1947 The tendency of Blackbird and Song Thrush to breed in their birthplaces. Brit. Birds, 40:328-330. Westernhagen, W. von 1957 Planbeobachtungen des Vogelzuges Herbst 1955. Mitt. Faun. Arbeitsgem. Schleswig-Holsteins. 10:17-55. Wharton, W. P. 1941 Twelve years of banding at Summerville, S. C. Bird-banding, 12:137-147. Williamson, K. 1955 Migrational drift. Acta XI Congr. Internatl. Ornith. Basel :\19-\2>6. 1962 The nature of ‘leading line’ behavior. Bird Migration 2:176-182. Woodcock, A. H. 1942 Soaring over the open sea. Sci. Mon., 55:226-232. DEPAFtTMENT OF ZOOLOGY, UNIVERSITY OF WISCONSIN, MADISON, WISCONSIN, AND THE CEDAR GROVE ORNITHOLOGICAL STATION, ROUTE 1, CEDAR GROVE, WISCONSIN. ( PRESENT ADDRESS: ( MUELLER ) , DEI’ARTMENT OF ZOOLOGY. UNI- VERSITY OF NORTH CAROLINA, CHAPEL HILL, NORTH CAROLINA.), 13 JAN- UARY 1966 THE CONTEXTS OF SONGS IN BLACK-THROATED GREEN AND BLACKBURNIAN WARBLERS Douglass H. Morse SOME recent studies of the family Parulidae demonstrate that in several species there is more than one type of male song; these song types evi- dently result from different motivations ( Ficken and Ficken, 1962, 1965: Morse, 1966 1 . The purposes of this investigation were to observe a situation where two or more closely related species are found within a homogenous, floristically simple habitat in order to determine the motivations of their songs, the relationship of the songs to the environment, and the degree of effect that the congeners have upon each others’ songs. In the northeastern Lnited States Black-throated Green Warblers [Dendroica virens) and Blackburnian Warblers ( D. fusca I are characteristically birds of the conifers, and while they may be found in mixed forests, it is in the coniferous forests that they reach their highest densities. Here they sometimes form the most prominent element of the local avifauna. Several other Dendroica warblers also occur in these forests. The pure spruce forests probably represent one of the simplest of arboreal habitats to support such an impressive array of closely related species of breeding birds. It appears probable that the existing ecological and behavioral relationships between Black-throated Green and Blackburnian warblers are the result of a past history of intense interactions between themselves and the other closely related sympatric species. As song appears to be an important part of warbler communication during the breeding season, an examination of vocalizations of these birds appeared to be a fruitful subject for study. These studies were made in the spring and summer from 1962 to 1965. ^lost of the work was done on Hog Island (Todd Wildlife Sanctuary I , Bremen, Lincoln Gounty, Maine, with additional work being done in several other areas in Maine, including the adjacent mainland and other coastal islands in Lincoln Gounty. Further brief observations were made at Tremont, Hancock Gounty, and Webster, Androscoggin County. Most of the area studied on Hog Island is a mature red and white spruce iPicea ruhens and P. glauca I forest, with the larger trees reaching a maximum height of 18 to 25 meters. The hurricanes of 1954 and winds of following years have severely damaged the forest on many parts of the island, but most of the work in this paper was conducted in relatively undisturbed areas. The growth of such a spruce forest is quite dense and results in considerable difficulties in studying and following birds. The warblers of similar stands 64 CONTEXT OF SONGS IN WARBLERS 65 Doiifilass H. Morse PERCENT OF OBSERVATIONS Fig. 1. Foraging height. of trees were studied briefly in other areas, and they were studied also in mixed white pine i Piniis strohus) — deciduous forests on the mainland. SPACE OCCUPIED IN THE HABITAT The foraging area of both species ( and other spruce-woods warblers ) was figured and discussed by MacArthur ( 1958 1 , who found that Black- burnian Warblers usually foraged at greater heights in the spruce forest than did Black-throated Green Warblers. In my study area, Blackburnian Warblers foraged higher than did any other species present, and Black-throated Green Warblers worked directly below them (Figure 1), with the other two congeners, Magnolia (D. magnolia) and Myrtle (/I. coronata) warlilers. usually foraging noticeably lower. While the centers of foraging of all species studied differed, there was considerable overlap in each instance. Cape May ( I). tif^rina I and Bay-hreasted ( I), castanea I warblers, two other spruce- woods species treated by MacArthur, were absent in the })rinci|)al study area. In addition to some songs that were given when the birds were foraging. 66 THE WILSON BULLETIN March 1%7 Vol. 79, No. 1 both species did a large percentage of their singing in a stationary or nearly stationary position from the top, or the tip of a high exposed limb, of a spruce tree. Both species sang for considerable periods in this sort of situation, remaining motionless except for “fidgeting” in the immediate vicinity of their song perch. Fidgeting here refers to an action in which an individual frequently flicks its wings and tail, hops about very deliberately within a limited area, and regularly pecks at the foliage, though apparently not feed- ing. These movements are frequently accompanied by songs and chipping notes. The term will be used in this sense throughout this paper. RELATIVE DENSITY OF THE TWO SPECIES The relative density of from two to three and one-half Black-throated Green Warblers to one Blackburnian Warbler found by Cadbury and Cruickshank ( 1937) in their long series of breeding-bird censuses on one part of this island probably is an accurate estimate of the present population. Frequent counts of the number of Black-throated Green and Blackburnian warbler songs heard along a transect through the middle of this forest sug- gested a similar or even greater ratio. Since their principal foraging areas are above the Black-throated Green Warblers, Blackburnian Warblers did not have as great an area in these spire-shaped trees in which to forage as did Black-throated Green Warblers, and this factor may account for part of the difference in density. Let us take an 18 meter spruce for an example, and assume that the Black-throated Green Warblers did the majority of their foraging at a height of between 5.4 and 12.6 meters ( 30-70 per cent of the height of the tree), and Blackburnian Warblers foraged from 9.0 to 16.2 meters ( 50-90 per cent of the height of the tree ) . Black-throated Green Warblers would then have approximately two and one-half times as great a volume of both bark surface and foliage in which to forage if this tree with its foliage had a normal radius of 3.4 meters at the minimum height here considered, 5.4 meters. SONG PATTERNS Both the Black-throated Green and Blackburnian warblers in this popula- tion possess two distinct song patterns, a male of either species typically rendering either one or the other, depending upon the motivation involved. To remain consistent with the literature. Black-throated Green Warbler songs are referred to as Type A Songs and Type B Songs (see Nice and Nice, 1932; Stein, 1962). Peterson (1947) described the Type A Songs as zoo zee zoo zoo zee and the Type B Song as zee zee zee zee zoo zee. Since the two Black- burnian Warbler songs are given in contexts essentially similar to those of the Black-throated Green Warbler, they will also be referred to as Type A Douglass H. Morse CONTEXT OF SONGS IN WARBLERS 67 Songs and Type B Songs, but this designation is not intended to imply that these songs are necessarily homologous to those of Black-throated Green Warblers. Peterson (1947) described the Blackburnian Warbler Type A Song as zip zip zip zip titi tseeeeee and the Type B Song as tizip tizip tizip tizip zizizizizizizizi. Songs classified as intermediate between Type A and Type B, comparable to “Intermediate Song” of the Yellow Warbler {Dendroica petechia) (Morse, 1966) , were not recorded from either species. While the Yellow Warblers sometimes sang Intermediate Songs while switching from one major song pattern to the other. Black-throated Green and Blackburnian warblers were not observed to do this. Occasionally a bird of either species would sing only part of a song pattern and then become silent. At the end of the breed- ing season many aberrant songs were heard, including some songs that were approximately intermediate to the two major patterns. However, these songs were not heard during the breeding season. Blackburnian Warblers oc- casionally rapidly alternated their two basic song patterns, but Black-throated Green Warblers were not observed to do so. STRATIFICATION OF SONGS A noticeable stratification of individuals singing either of the two song patterns into distinct parts of the habitat occurred in the Black-throated Green Warbler ( Fig. 2 ) . The Type A Song was strongly associated with the treetops and almost all Type A Songs were given from a high elevation. This song was usually given while the bird was nearly stationary in the treetops, but sometimes it was given while the singer alternately foraged. Type B Songs were strongly associated with a lower position ( moderate height ) dur- ing most of the season, and in contrast to Type A Songs were usually given while the bird was actively foraging. Early in the season during the period in which males were setting up territories and acquiring mates, stationary birds in high exposed positions frequently gave Type B Songs, probably acting as an advertising song. The two basic song patterns of Blackburnian Warblers ( Fig. 3 ) occurred in situations rather similar to those of Black-throated Green Warblers. Type A Songs were also most frequently given while stationary in the top of spruces, and Type B Songs were most frequently sung while foraging. How- ever, the tendency for this species to forage higher than any other species in the study area led to a superficial difference from Black-throated Green Warblers in that there was a strong tendency for the Type B Song (the foraging song ) to be given from a considerable height. The two songs some- times were even alternated by a single bird at a high elevation. There also was a strong tendency for this species to sing Type B Songs while in a 68 THE WILSON BULLETIN March 1967 Vol. 79. No. 1 Fig. 2. Singing height of Black-throated Green arbler. Stationary position early in the season in conjunction with its apparent role as an advertising song at that time. The heavv incidence of Type B Song recorded in or near the top of the trees is attributable to this effect in both Black-throated Green and Blackburnian warblers. BEHAVIOR ACCOAIPANYING THE SONGS Black-throated Green arbler Type A Songs were most frequentlv heard from stationary birds in exposed positions that appeared to sing this pattern as a territorial proclamation. These songs were also associated with activities related to direct territorial defense. henever a male Black-throated Green W arbler became conspicuous to other Black-throated Green arblers at close range i except in the case of apparently unmated birds i . they responded with Tvpe A Songs from a prominent position, even if they had previously been singing Type B Songs. This song (sometimes muted I followed fights and chases between male Black-throated Green arblers and also the less frequent interspecific fights or chases with Parula iParula americana). Myrtle, or Blackburnian warblers (Table li. ’’Muted Songs'* almost always followed Douglass H. Morse CONTEXT OF SONGS IN WARBLERS 69 Type B Song N=47 10 15 20 25 30 35 40 45 50 0 5 10 PERCENT OF OBSERVATIONS Fig. 3. .Singing height of Blackburnian Warbler. 15 io 25 30 the same contexts as normal volume songs did, though usually being given in particularly strong or long encounters. In the course of a single fight between two male Black-throated Green Warblers, both Muted Type A Songs and Muted Type B Songs were heard. During such encounters, frequent “Metallic Double Chips” were given between Type A Songs, and at times of most intense aggression and excitement the song was sometimes even temporarily suspended. These chips, which are of a distinctly metallic char- acter, are usually given rapidly in groups of two. Type B Songs frequently appeared directed toward females in one way or another. On the few occasions that the male was seen singing in the direct company of a female of the same species. Type B Songs were always given (Table 1). These meetings probably occurred upon the frequent other oc- casions when males dropped out of sight to lower positions from treetop singing perches and changed from Type A to Type B patterns. Type B Songs are the typical foraging songs, and most foraging is performed at the height where females are most frequently encountered and where nesting occurs ( see Cruickshank, 1956 ) . Metallic Double Chips never accompanied this song, a characteristic noted also by Nice and Nice (1932). Occasional in- dividuals that sang Type B Songs while stationary in the treetops for several minutes at a time into mid-June appeared to be unpaired birds. A noticeable decrease of this behavior occurred during early June. Blackburnian Warbler Type A Songs usually were correlated with activities quite similar to those of Black-throated Green Warblers while singing l ype A Songs (Table 2), occurring in both interspecific and intraspecific situa- tions. A larger fraction ( 40.0 per cent ) of the strong or long encounters were interspecific in this species than in Black-throated Green Warblers ( 22. 1 per cent). Blackburnian Warblers tended to remain in one jiosition while singing 70 THE WILSON BULLETIN March 1967 Vol. 79, No. ] Table 1 Apparent Context for Some Songs of Male Black-throated Green Warblers* Number of Activity responses Type A Song Fight with male Black-throated Green Warbler 32 (8 muted) Extremely close contact with male Black-throated Green Warbler 4 Close contact with male Black-throated Green Warbler many Song suspended and only metallic double chips given accompanying fight with male Black-throated Green Warbler 2 Fight with male Blackburnian Warbler 4 Extremely close contact with male Blackburnian Warbler 2 Fight with male Myrtle Warbler 1 (muted) Extremely close contact with male Myrtle Warbler 2 (1 muted) Fight with male Magnolia Warbler 1 Fight with male Parula Warbler 1 Interference of observer 2 Type B Song Following copulation with female Black-throated Green Warbler 1 Following courtship of female Black-throated Green Warbler 2 (1 muted) Extremely near female Black-throated Green Warbler 3 (1 muted) Continual singing early in the season from an exposed perch many N * Upon one occasion, after two male Black-throated Green Warblers fought they alternated Muted Type A and Muted Type B Songs. Type A Songs somewhat longer than did Black-throated Green Warblers, averaging 4.8 minutes per singing station, while Black-throated Green War- blers averaged 3.9 minutes per singing station. Blackburnian Warbler en- counters with Parula Warblers, as well as with Black-throated Green War- blers, were observed. Under circumstances resulting in high aggression, frequent chipping, occasionally of a double nature, was given. The birds sometimes foraged at this time. In this species also. Type B Songs were the ones given in the immediate presence of females (Table 2). Individuals consistently singing this song for long periods of time in the treetops were probably birds that had not obtained a mate. Two birds sang in such a manner through most of June, though most ceased this pattern by early June. Only on very rare occasions (two observations) were the chips heard accompanying Type B Songs. DISCUSSION The contexts in which both species sing Type A Songs and Type B Songs suggest that the Type A Songs are given in situations where there is a high attack tendency or a conflict of attack and escape tendencies. Type B Songs Douglass H. Morse CONTEXT OF SONGS IN WARBLERS 71 Table 2 Apparent Context for Some Songs of Male Blackburnian Warblers Number of Activity responses Type A Song Fight with male Blackhurnian Warhler 4 Extremely close contact with male Blackhurnian Warbler 8 Close contact with male Blackburnian Warbler many Fight with male Black-throated Green Warhler 4 (2 muted) Extremely close contact with male Black-throated Green Warbler 2 Extremely close contact with male Parula Warbler 2 Type B Song Following copulation with female Blackburnian Warhler 1 Following female Blackburnian Warbler 1 Extremely close contact with female Blackburnian Warbler 1 (muted) Continual singing early in the season from an exposed perch many A = 23 appear to be given under circumstances in which these tendencies are less strongly activated, and in which sexual tendencies may be high. Type A Songs appeared to be the territorial songs and were usually delivered from exposed perches while nearly stationary. Type B Songs were typically forag- ing songs and were also given in the presence of females. They were also given as apparent advertising songs early in the season from exposed positions. The contexts of the Type A Songs of the Black-throated Green and Black- burnian warblers most closely resemble those that accompanied the Yellow and Chestnut-sided (Dendroica pensylvanica) warbler Unaccented Ending Songs (see Morse, 1966), all of these songs usually being given in the close presence of other males of the same species. Type B Songs occurred in contexts suggesting those in which Yellow and Chestnut-sided warblers sang Accented Ending Songs; however, there appeared to be no distinction made by Black-throated Green and Blackburnian warblers in response to other closely related species nesting in the same areas. The difference between a response of a Black-throated Green Warbler male to another male of its species and to one of some other species was not marked, both intraspecific and interspecific hostile activities usually being accompanied by the same song pattern (Type A Song). In several populations in Maine, Yellow Warblers responded to their most closely related sympatric species, the Chest- nut-sided Warbler, with the same song pattern that they directed toward the female. The factors governing the singing of a particular song pattern differ somewhat in the two cases. The level of hostile behavior among spruce-woods 72 THE WILSON BULLETIN March 1%7 Vol. 79, No. 1 Dendroica warblers probably is considerably more intense than it is between Yellow and Chestnut-sided warblers, and the problem of frequent inter- specific interaction may be more important than is that of simple recognition. The habitat separation between Yellow and Chestnut-sided warblers is more clearly delimited than it is between the spruce-woods Dendroica species, only limited habitat overlap occurring in the populations studied. Black-throated Green and Blackburnian warblers both utilize very similar habitats, having their principal foraging and nesting areas at slightly different heights ( Cruickshank, 1956 1 and parts of the trees, and foraging somewhat differ- ently ( see MacArthur, 1958 ) . hut nevertheless overlapping considerably in all these characteristics. Many more closely related species are found in the spruce forests than in the favored wet bushy habitat of the Yellow Warbler. Thus, a high level of interspecific interaction among the birds of the spruce forest may result in stronger attack or escape tendencies than occur in Yellow or Chestnut-sided warblers. The slight difference in context accompanying a particular song pattern or foraging in these two species may he partly attributable to the difference in the part of the habitat foraged by them. The stratification of birds singing the two song types was less marked in Blackburnian Warblers than in Black- throated Green Warblers, and the former spent most of their time within an area in which it was customary to give either song or to forage. They were thus exposed to a slightly different set of stimuli at this height than were Black-throated Green Warblers both in the treetops and at lower heights. This difference in foraging height is in turn probably enforced by inter- actions between the two species. The context of muted songs in both of these species, based upon a limited number of observations (see Tables 1 and 2), was slightly more predictable than in Yellow Warblers (see Morse, 1966). The difference is perhaps a result of the heavy incidence of interspecific interactions in the spruce forest. The higher ratio of interspecific fights and chases to intraspecific ones in the Blackburnian Warbler in comparison to the Black-throated Green War- bler was probably largely the result of the lower density of the Blackburnian Warbler in the study area. The somewhat longer periods of stationary sing- ing in Blackburnian Warblers may also be the result of this low density. No noticeable difference in the intensity and duration of hostile activities was noted between the two species. Because of their particular foraging station. Black-throated Green Warblers would experience more potential conflicts with Magnolia and Myrtle warblers than would Blackburnian Warblers. However, the foraging of Magnolia Warblers ( pers. obs. I and Myrtle Warblers ( MacArthur, 1958) is not as similar to Black-throated Green Warbler foraging as is Blackburnian Warbler Douglass H. Morse CONTEXT OF SONGS IN WARBLERS 73 foraging, and much of the Black-throated Green Warbler foraging is per- formed above the major foraging areas of Magnolia and Myrtle warblers. Fewer Black-tbroated Green Warbler encounters with Magnolia and Myrtle warblers were noted than between Black-throated Green and Blackburnian warblers. Magnolia and Myrtle warblers also were not as abundant as were Black-tbroated Green and even Blackburnian Warblers in the study area. Thus Blackburnian Warblers expend more energy in interspecific encounters ( at least their fights and chases ) in this forest than do Black-throated Green Warblers. It is not definite whether the warblers of tbis forest are utilizing limited food sources at this season, but they definitely interfere with each other in the procurement of quite similar food sources. Thus they fulfill requirements for competition laid out by Birch ( 1957 ) . The most important competitor of the Blackburnian Warbler in this forest probably is the Black-throated Green Warbler, the only species of warbler it frequently comes into contact with, and which forages in a manner suggestive of, though not identical to, its own species. Conversely, Blackburnian Warblers probably are the most important competitors of Black-throated Green Warblers in this forest, but because of their lower density their effect is quantitatively less important than the effect that Black-throated Green Warblers have upon Blackburnian Warblers. This pattern will necessarily be modified depending upon the local species compositions, but it appears likely that these two species have more foraging similarities than do any other Dendroica warblers in tbe spruce forests of tbe northeast. SUMMARY Songs and accompanying behavior of Black-throated Green and Blackburnian warblers were studied in Maine from 1962 to 1965. Work was concentrated in a climax spruce forest containing two additional species of Dendroica, Magnolia and Myrtle warblers. Blackburnian Warblers foraged higher than did other species, with Black-throated Green Warblers directly below them. Both possess Type A and Type B Songs, usually sing- ing Type A Songs in the presence of other singing warlders of either their own or other species. These vocalizations appeared to he the territorial songs and were usually de- livered from exposed perches while nearly stationary. Metallic Double Chips often aceompanied Type A Songs. Type B Songs were typically foraging songs and were also given in the presence of females. They were also given as apparent advertising songs early in the season from exposed positions. Type A Songs were apparently sung when a high attack tendency or a conflict of attack and escape tendencies existed; Type B Songs oecurred when these tendencies were less strongly activated, and when sexual tendencies were high. The slight difference in context accompanying certain responses in the two species may he partly attributable to their differences in foraging j height. Black-throated Green Warblers were more abundant than Blackburnian j Warblers in the study area, and a greater portion of their hostile activities were intra- I specific. Both species j)rohahly were the other’s mo‘;t important comj)etitor. 1 I 74 THE WILSON BULLETIN March 1%: Vol. 79, No. 1 ACKNOWLEDGMENTS I wish to thank Drs. M. S. and R. W. Ficken for timely discussion and criticism of the manuscript. The National Audubon Society kindly permitted the study to he con- ducted on Hog Island. This study was partially supported by the National Science Foundation (GB-3226). LITERATURE CITED Bmcii, L. C. 1957 The meanings of competition. Am. Naturalist, 91:5-18. Cadbury, J. M., and A. D. Cruicksiiank 1937 Climax red and white spruce forest. Bird Lore, 39:384 (and subsequent years through 1958). Cruicksiiank, A. D. 1956 Nesting heights of some woodland warblers in Maine. Wilson Bull., 68:157. Ficken, M. S., and R. W. Ficken 1962 The comparative ethology of the wood warblers: a review. Living Bird, 1: 103-122. 1965 Comparative ethology of the Chestnut-sided Warbler, Yellow Warbler, and American Redstart. Wilson Bull., 77:363-375. MacArtiiur, R. H. 1958 Population ecology of some warblers of northeastern coniferous forests. Ecology, 39:599-619. Morse, D. H. 1966 The context of songs in the Yellow Warbler. Wilson Bull. 78:444-455. Nice, M. M., and L. B. Nice 1932 A study of two nests of the Black-throated Green Warbler. Bird-banding, 3:95-105, 157-172. Peterson, R. T. 1947 A field guide to the birds. Floughton Mifflin Co., Boston. Stein, R. C. 1962 A comparative study of songs recorded from five closely related warblers. Living Bird, 1:61-71. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MARYLAND, COLLEGE PARK, MARY- LAND, 1 DECEMBER 1965 DAMAGE BY GOLDEN-FRONTED AND LADDER-BACKED WOODPECKERS TO FENCE POSTS AND UTILITY POLES IN SOUTH TEXAS John V. Dennis OODPECKER damage to utility poles is a matter of serious economic W concern in many parts of North America. The problem dates back into the last century, and periodically has received serious attention from ornithol- ogists and utility engineers. An early study by McAtee (1911) showed that poles treated with a preservative as well as untreated poles are attacked, and that at least eight species of woodpeckers are responsible for damage. However, neither McAtee nor other early writers seem to have recognized the situation existing in south Texas where two pole-damaging species of woodpeckers occupy the same habitat. Most writers blame the Golden-fronted Woodpecker {Centurus aurijrons) (Fig. 1) for the extensive damage that occurs. Sennett ( 1878u ) , for example, reported that utility poles were a favorite nesting place of the Golden-fronted and that “hardly a pole” was free of their holes. He concluded that telegraph pole excavations by this species were made “in search of a large species of borer that works in dry wood” ( Sennett, 18786 ) . The only other resident woodpecker of the lower Rio Grande Valley is a sparrow-sized bird, the Ladder-backed Woodpecker ( Dendrocopos scalaris) . Sennett ( 1878a) implied that this species also nested in utility poles. Simmons ( 1925 ) , writing of the region of Austin, Texas, states that “when suitable trees are not to be found” the Ladder-backed nests in cedar fence posts or telegraph poles. McAtee (1911) and Pearson et al. (1936) mentioned the Ladder-backed in connection with utility pole nesting. Until recently the Golden-fronted has received much more blame for utility pole damage ( Bendire, 1895; McAtee, 1911; Friedmann, 1925; Simmons, 1925; Pearson et al., 1936; Quillin in Bent, 1939). The present paper attempts to define the roles played by the Ladder-backed and Golden-fronted woodpeckers in regard to utility pole and fence post damage in Texas from about Victoria and San Antonio southward. Other objectives are to describe damage and to explore reasons for attack. These are subjects discussed earlier by Dennis (1961), but which have now been ex- amined further. Methods of preventing attack are beyond the scope of the present paper and will not be covered. Observations in south Texas now cover three nesting seasons as well as appreciable periods during the non-nesting season. During the winters of 1960-1961 and 1961-1962, observations were made in parts of the Lower 75 76 THE WILSON BULLETIN Marcli l')67 Vol. 70. No. 1 Fig. 1. Female Golden-fronted Woodpecker at nest hole in a small electric distribution pole. Hole is about six feet from the ground. John V. Dennis WOODPECKER DAMAGE IN TEXAS 77 Rio Grande Valley and south Texas where both the Golden-fronted and Ladder-hacked are abundant. During the late winter and spring of 1965, the writer with Robert L. Rumsey of the Southern Forest Experiment Station, established a number of tests in south Texas for the purpose of comparing susceptibility of certain woods and treated versus non-treated woods to attack by Golden-fronted and Ladder-backed woodpeckers. This work was part of a much wider program to find better methods of protecting wooden utility poles from damage by woodpeckers. The program is under the direction of the Southern Forest Experiment Station at Alexandria, Louisiana, and is financed by several electric utility companies and a lumber company. HABITAT AND NUMBERS In Mexico the Ladder-backed is said to be found “virtually country-wide in arid districts,” and the Golden-fronted in “dry districts with sparse or second-growth timber” (Blake, 1954). In Texas the two are almost always associated with the mesquite-dominated chaparral that extends northward from Mexico into the hot, arid, southern, central, and western parts of the State. Although land clearing has destroyed vast areas of mesquite, it seems probable that more mesquite scrubland exists today than at the time of Sennett’s writings in 1878. Since mesquite spreads with intensive grazing, it is not surprising that it has become established widely over the more arid rangeland of Texas. Brooks ( 1933 ) , writing of the Brownsville region, mentions the rapid invasion of mesquite over the once wide coastal prairies. Oaks and mesquite are the species usually mentioned as affording habitat for the two species. Simmons ( 1925 ) , besides listing oaks and mesquite, states that the Golden-fronted is partial to pecan groves and the Ladder-backed to cottonwoods and hackberry. In extremely dry and treeless sections of the Southwest the Ladder-backed is found closely associated with yucca and agave. Grinnell and Swarth ( 1913 ) state that the birds nest in the dried stalks of these plants in desert regions of southern California. Bancroft ( 1930 ) reports that a race of the Ladder-hacked in lower California confines its nesting to the saguaro cactus. Neither the Ladder-backed nor Golden-fronted has adapted to the more intensively cultivated parts of the Rio Grande Valley and Texas coast, hut both have responded to shade tree plantings. The Golden-fronted, in particular, has resj)onded to man-created environments, and shows a strong affinity for introduced palm trees. Both Sennett (18785) and Bendire (1895) found that the Ladder-hacked was much less numerous than the Golden-fronted in the Lower Rio (irande Valley. While their conclusions may he accurate, it should he enq)hasized that the larger, more colorful and vocal Ciolden-fronted often disphns in the oj)cn. 78 THE WILSON BULLETIN Marcli 1067 Vol. 70. No. 1 easily conveying an exaggerated impression of its numbers. The less con- spicuous Ladder-backed, on the other hand, is apt to be overlooked. In a random selection of Christmas Bird Counts, the writer has noted that total numbers of the two were about the same at 12 localities in Texas reporting both species — 187 Golden-fronted Woodpeckers and 182 Ladder-backed \^^ood- peckers (Cruickshank et ah, 1958). These recent results agree with those obtained by the writer, who found the two species to be about equally numerous throughout south Texas. ROLE OF THE LADDER-BACKED VERSUS THE GOLDEN-FRONTED Special attention was given to the comparative roles played by the Ladder- backed and Golden-fronted Woodpeckers in damage to poles and posts. It was concluded that the Golden-fronted rarely initiates attack, but rather appropri- ates and enlarges holes already made by the smaller Ladder-hacked. Support- ing evidence may be summarized as follows: 1. Golden-fronted Woodpeckers have appeared as occupants of sites where Ladder-backs were actively at work earlier in the same nesting season. 2. There is no evidence of damage to utility poles or crossarms in towns and cities in the Rio Grande Valley where the Golden-fronted is reason- ably common and the Ladder-backed is rare or absent. 3. Golden-fronteds are rarely seen working on utility poles. They spend much of their time on poles, but this time is utilized chiefly in such activities as guarding nesting sites, “loafing,” searching for food in checks, and taking part in courtship displays. Ladder-backs, however, when seen on poles or fence posts, are rarely engaged in anything but hole excavating activity. LOCATION OF DAMAGE Each of the several species of woodpeckers that attack utility poles has its special mode and place of attack; the Pileated { Dryocopus pileatus) concen- trates on the mid- and upper-mid portions of transmission poles; the two flickers iColaptes cajer and C. auratus) on lower portions of the pole, often close to the ground; and other pole-damaging species have equally rigid zones of attack ( Dennis, 1964 1 . The Ladder-backed conforms to this pattern by concentrating its attack at special localized points on poles, fence posts, and other structures. However, it exceeds all other pole-damaging species in the wide diversity of its attack. Among its targets are every wooden utility pole attachment, road marker posts, sign posts, fencing boards, wooden railings, and clapboard on houses. Lurthermore, the writer has been told by utility engineers within the Ladder- hacks’ range that lead sheathing on overhead cables is sometimes damaged. John V. Dennis WOODPECKER DAMAGE IN TEXAS 79 Fig. 2. Distribution of holes on this telephone pole is typical of Fudder-hacked's work. Heaviest attack is near the top of pole. A few holes are found on the lower portion and heginning almost from the firound level. 80 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 Attack on utility pole structures by the Ladder-backed is characterized by heavy damage to crossarms and braces, and frequent heavy damage to the top 2 or 3 feet of the pole. Damage sometimes extends from ground level to the top of the pole ( Eig, 2 ) . Attack on crossarms and braces always originates on the underside, never the sides or top. Typically, a crossarm is drilled at a site on the underside from 6 to 18 inches from the end. The purpose of this drilling is apparently the excavation of a roosting or nesting hole. Rarely are these holes completed. Often the bird “misjudges” the dimensions of the crossarm and breaks “windows” in one or both sides, or breaks a hole in the top. In other cases, the bird appears to tire of its work and discontinues after drilling only an inch or two. In the rare instances that a cavity is completed, the tunnel always leads from the entrance toward the pole — never away from the pole. Completed cavities in crossarms are from 6 to 10 inches in length. Attack on fence posts is much like that on utility poles. Roosting and nesting holes are largely confined to the top few inches of the post, and many more are started than are completed. Damage to utility poles and fenceposts can be described best under three headings: (1) small poles with crossarms ( electric distribution and telephone poles ) , ( 2 ) large poles with crossarms (electric transmission poles), and (3) fence posts. Small poles. — A total of 155 small poles in seven separate electric distribu- tion lines were checked for location of damage and severity of damage in rela- tion to habitat. The poles had been in service from 4 to 19 years and ranged from 20 to 40 feet tall; each had a single crossarm attached. With the excep- tion of one line in which the treatment was pentachlorophenol, all poles were treated with creosote. Poles were southern pine and crossarms were penta- treated Douglas fir. All but a few poles were damaged ( only holes 2 inches or more in diameter were tallied ) . The heaviest damage occurred through dense mesquite shrub, where poles had an average of 3 holes each. Lightest damage — 0.5 hole per pole — was found in a line through small bottomland hardwoods along the Rio Grande. Damage was intermediate where lines passed through habitats with predominately large hardwood, and mixed oaks and mesquite. One hundred and seven pressure-treated, southern pine telephone poles were examined on six different lines. The poles ranged from 15 to 30 feet tall and had two to three crossarms. Only 0.8 hole per pole was found where lines were surrounded by solid stands of oak; in contrast an average of 2.5 holes per pole occurred in lines through mesquite scrub. Severity of damage was about the same as on the electric distribution lines. Combining data from telephone and electric distribution lines, about 26 per cent of all holes were in the top foot of poles, 30 per cent were at the crossarm level, 30 per cent were in crossarms, and the remainder below the crossarms. John V. Dennis WOODPECKER DAMAGE IN TEXAS 81 Overall, 80 per cent of the damage was in the top 3 feet and in the crossarms. Large poles. — Several kinds of transmission pole constructions are found in south Texas. The poles are southern pine, pressure-treated with creosote, and typically 55 feet in height. The various braces and crossarms are penta-treated Douglas fir. In April 1965, 30 consecutive 2-pole, H-frame structures of a transmission line west of Falfurrias were checked for woodpecker damage. As was the case with the smaller poles, this line seemed to be a typical example of the kind of woodpecker damage to be expected where adjacent habitat supports a large population. Habitat along this line consisted of dense mesquite scrub. Approximately 75 per cent of the larger holes were found in X- and V-brace structures, only 24 per cent in the pole, and 1.6 per cent in the crossarms. This is in marked contrast to the heavy damage typically found in crossarms on electric distribution lines and telephone lines. That Douglas fir crossarms on this line and other transmission lines examined have been free or nearly free of attack defies explanation. Whether a factor, such as elevation from the ground or the thickness of the crossarm, plays a role in degree of attack on the different structures in unknown. However this may be, the damage to the pole itself on transmission lines has seldom been found to be severe and is largely confined to the top few feet. Fence posts. — Although several species of woodpeckers attack both utility poles and fence posts, attack upon creosoted pine fence posts for the purpose of making roosting and nesting holes seems to be a highly restricted habit that is perhaps confined to only the Ladder-backed Woodpecker. Numerous in- stances were found in which the Golden-fronted had occupied holes in creosoted pine fence posts, but from all evidence, such holes were originally the work of the Ladder-backed. Creosoted pine posts have been used on a large scale in south Texas only during the last 10 to 20 years. The traditional fence posts of the region are red cedar { Juniperus virginiana) and mesquite iProsopis juliflora) which are naturally resistant to decay. Pressure-treated creosoted pine, however, is becoming more popular as a fence post material. Pressure-treated penta-pine posts also are beginning to make an appearance. Red cedar, the most widely used fencepost material, is virtually immune to woodpecker attack. Occasion- ally a roosting or nesting hole is found in a red cedar post, hut upon examina- tion the post is usually found to he in an advanced state of internal decay. More often, a few “probe holes,” which rarely penetrate any deeper than the sapwood, are found in sound posts. In response to an inquiry to the L.S. forest Products Laboratory at Madison, Wisconsin, John W. Rowe ( i)ers. comm., 5 April 1961) furnished the following information regarding possible reasons why red cedar is so seldom attacked by woodpeckers: 82 THE WILSON BULLETIN Marcli 1967 Vol. 79, No. 1 “Woodpeckers apparently attack wood either to find insects or when they hear a hollow sound such as might come from either heartwood rot or shake (the ease of hollowing out for nesting?). These Juniperus species contain a high percentage of heartwood which is rich in toxic extracts . . . They are considered fairly resistant to attack hy micro- organisms and fungi, and are probably also fairly resistant to insect attack . . . The heartwood is thus resistant to rot, and in addition is relatively hard and does not commonly form shake cavities. This should all tend to render these Juniperus spp. relatively unattractive to woodpeckers.” Mesquite fence posts, readily recognized by their crookedness, are also widely used in south Texas. They are somewhat more subject to woodpecker attack than red cedar. Roosting and nesting holes are sometimes found, and if the post has a marked lean or crook, the hole is invariably on the undersurface. Solid posts without decay seem to be avoided. Mesquite posts generally seem to be free of small “probe” holes and miscellaneous damage. However, in some parts of south Texas, for example along the highway between Alice and George West, attack upon mesquite posts is quite common. By far the heaviest attack is upon creosoted pine. Wherever such fence lines were checked in mesquite-scrub habitat, there was evidence of damage similar to that found on utility poles, specifically holes near the top, widening of checks, minor surface peck marks and scaling. The ratio of completed to un- completed holes does not vary strikingly from that found on utility poles and crossarms. For example, in a check of 50 distribution poles and 60 crossarms at the Welder Refuge near Sinton, only 5 per cent of all holes were completed roosting and nesting cavities (Dennis, 1964). On 525 creosoted pine fence posts at the Laguna Atascosa National Wildlife Refuge near San Benito, Texas, 11 per cent of all holes were completed roosting and nesting cavities. The poles and crossarms had been in place approximately four years and the fence posts about seven years. A higher percentage of poles than posts is attacked. In areas of severe damage it is not uncommon for 100 per cent of utility pole structures to show signs of attack. The incidence is lower in fence posts which are spaced closer together. For example, in a part of the Laguna Atascosa Refuge where every utility pole showed substantial damage, only 17 per cent of the fence posts contained damage. The fence posts were one rod apart while the utility poles were approximately 500 feet apart. Approximately 16 per cent of 1,887 creosoted pine posts in six lines at the Laguna Atascosa Refuge were damaged. Furthermore, 2.5 per cent con- tained completed roosting or nesting holes. The posts had been in place from two to seven years. Damage was most severe on fence lines where there were either solid stands of mesquite-scrub or mesquite-scrub bordered by grassland. Less damage was John V. Dennis WOODPECKER DAMAGE IN TEXAS 83 found on lines where at least one side of the fence line was bordered by a cultivated field. Wherever fence lines departed from chaparral, woodpecker damage ceased within 40 to 50 yards. RELATIONSHIP OF DAMAGE TO WOOD TREATMENT C. T. Day, a utility engineer in Sonora, Mexico, (in McAtee, 1911) describes woodpeckers “getting fat” on creosote and the inside of poles being “entirely eaten away.” Although this may be an exaggerated account, the idea that creosote makes a pole more susceptible to woodpecker damage has persisted. A program to test this theory was established at the Laguna Atascosa National Wildlife Refuge with the cooperation and assistance of the U.S. Fish and Wildlife Service. In February 1965, 58 pressure-treated creosoted south- ern pine posts and 42 untreated southern pine were placed about 20 yards apart along edges of existing fence rows or along clearings through dense chaparral growth. In most instances treated and untreated posts were alter- nated. After approximately two months, the posts were examined for signs of attack. Of the untreated posts, 7.3 per cent contained holes or sign of attack and 36.2 per cent of the treated posts contained holes or sign of attack. The extent and degree of damage varied little between treated and untreated posts. None contained completed nesting holes. For the most part, holes went straight into the post for varying distances and did not extend downward. In some cases, attack was limited to a few peck marks or the scaling-off of thin layers at surface of the post. The fact that the creosoted posts sustained approximately five times as much damage in the first two months suggests that there is a basis for the belief that the wood preservative in some way contributes to making a pole more vulner- able to woodpecker attack. This does not necessarily imply, however, that creosote per se is the attractant. Changes in wood structure during the treating process may be a factor in making a pole more vulnerable. For ex- ample, Wood et al. (1960) speak of defects in poles, such as shakes, “that are induced by conditioning and preservative treatment.” Poles and posts with small internal cavities in the form of ring sejjarations in the wood (or shakes) have often been thought to be particularly susceptible to woodpecker attack. In the letter from John W. Rowe quoted earlier, it was suggested that the presence of either heartwood rot or shake made for con- ditions that stimulated woodpecker attack. This is a theme amplified uj)on by Dennis ( 1964), who believed that woodpeckers primarily attack poles to make roosting and nesting cavities, but, because of the presence of shake and other I 84 THE WILSON BULLETIN March 1967 Vol. 79, No. 1 internal defects, are stimulated to make far more holes than they would in natural tree sites. It should be added that there is much yet to be learned about a possible connection between the preservative treatment and the susceptibility of a pole to woodpecker attack. Testing has barely begun on this aspect of the prob- lem and any conclusions will have to await long-term results with many more test poles. In April 1965, the number of test posts in the experiment at the Laguna Atascosa Refuge was doubled. RELATIONSHIP OF DAMAGE TO RESONANCY EFFECTS Other fence post experiments at Laguna Atascosa were designed to test resonancy or sound effect. McAtee (1911), who expressed the belief that “hum of the wires” had something to do with attracting woodpeckers to utility poles, was repeating a widely held assumption that has persisted to this day. Recent writers have discounted the role of hum or vibration and have substituted other reasons that seem more convincing (Turcek, 1960; Dennis, 1964). Observations along electric distribution and telephone lines in south Texas, as well as of posts bearing metal signs, have shown that the Ladder-backed frequently selects sites close to metal attachments as places to commence hole drilling. So pronounced is this tendency that attack is often limited almost entirely to the immediate proximity of a metal attachment and is absent elsewhere. A number of examples may be mentioned. 1. In a sample of 17 poles in a heavily damaged electric distribution line, 88 per cent of holes were opposite metal attachments. 2. In a sample of 50 poles in a heavily damaged telephone line, all holes were opposite metal attachments on the crossarms. 3. At Laguna Atascosa Refuge about 2.5 per cent of the creosoted pine posts bear official metal U.S. Fish and Wildlife Service boundary marker signs. In a fence line containing 525 posts, 13 with signs attached sustained a damage rate of 84.6 per cent; the 512 posts without metal signs sustained a damage rate of 15.4 per cent. This tendency to attack locations opposite metal attachments was tested on a small scale in fence post experiments at the Laguna Atascosa Refuge. A slit 5 inches deep was sawed into the top of 10 creosoted pine fence posts. A 5-inch square of sheet metal was inserted into each slit. Posts containing the hidden metal plates were placed in test strips with 30 unaltered creosoted pine fence posts. As with the other test posts, placement was made in late Febru- ary and posts were checked in late April. Of the 30 unaltered posts, six (20 per cent) had been attacked; of the 10 posts with metal plates, seven (70 per Jolin V. Dennis WOODPECKER DAMAGE IN TEXAS 85 Fig. 3. A flat metal plate has lu'en inserted into a jiroove cut into tlie top of tliis ereosoted pine fence post. A woodjiecker has drilled a hole to tin* plate, .'''mail hoh's are scatt(‘red about near the lar

ierra where it often frequents slash-burned sections in which stumps and fallen trees provide cover. Gommon Mockingbird (Mimas polyglottos) 1 he only mockingbird I observed in 184 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 the Sierra was one at Playa Azul on 2 April 1960, during a norther. It was a typical individual of this species. White-throated Robin (Turdus assimi/is). — On 5 June 1962, I discovered a nest in the understory of montane rain forest on Volcan San Martin Tuxtla at 750 m elevation. It was constructed of green moss, supported by a vine and small branches, and situated about 3.5 m above ground against the trunk of a tree 30 cm DBH. I could not de- termine its contents. At the time robins were feeding two-thirds grown young in the rain forest as were Ivory-billed Woodcreepers {Xiphorhynchus flavigaster) , Red-legged Honeycreepers iCyanerpes cyaneus) , and Chestnut-capped Brush-Finches ( Atlapetes brunneinucha) . In July T. assimilis was the most common species I noted in this rain forest on the volcano. It is of interest that Skutch (1960:85) could find no pub- lished record of the nesting of this species in Central America, and the seven nests that he observed were apparently not in forest habitat. Black Robin i Turdus injuscatus) . — 1 collected a male with testes each 3.5 mm in elfin forest at 1600 m on Volcan San Martin Tuxtla on 26 August 1962. Another bird, possibly the female, was calling and exhibiting alarm in the same place. Two others were seen at slightly lower elevations. The small areas of cloud forest in the Sierra limit the available habitat for this species. Tropical Parula Warbler (Parula pitiayumi) . — This warbler is a widespread resident in humid and drier forests. I collected a singing male in breeding condition near Barrosa on 16 June 1962. These warblers habitually sing late into the morning and often in the afternoon on hot days when most species are quiet. The Mexican Check- list (Miller et ah, 1957:243-244) records the species as only casual in northeast Oaxaca and central and southern Veracruz. Golden-crowned Warbler (Basileuterus culicivorus) . — I found a nest at 730 m in the forest on Valcan San Martin Tuxtla on 5 June 1962. It was on the ground in an open section of the forest among leaves and low herbaceous plants. Construction was of leaves, grasses, and rootlets in a dome shape with the interior 7.5 cm in diameter and lined with fine rootlets. The three eggs were pinkish-white with reddish-brown flecks over the entire surface but concentrated in a ring near the large end. One measured 18 by 13 mm. Cbestnut-headed Oropendola iZarhynchus wagleri). — Sclater (18576:228) reported this species from San Andres Tuxtla, and Ramirez collected a female and male at Dos Amates on 14 and 23 November 1961. Apparently the species is very rare and local in the Sierra. Wagler’s Oriole ilcteriis wagleri). — Davis (1952:315) reported this species south of Lake Catemaco in 1952, the only record. Although the Mexican Check-List does not list this oriole for Veracruz, it seems likely that it would occur there in highlands in view of its known overall distribution. Hooded Oriole (Icterus cucullatus). — Dickerman reported four birds north of Sontecomapan on 7 August 1962, the only record for the Sierra. Blue-hooded Euphonia (Euphonia musica) . — On 22 March 1960, I observed a pair above Dos Amates, saw a male on 20 March 1962, above Colonia Huatusco, and another individual on 30 October 1962, above Ocotal Chico. Phillips reported about eight and collected a male above Ocotal Chico on 8 December 1962. Another was taken by Ramirez near Dos Amates on 6 November 1963. Since the Mexican Check-List (Miller et ah, 1957:298) lists the species only from La Joya in Veracruz, apparently these are the first records outside the west-central mountains of the state. Yellow-throated Euphonia (Euphonia lauta) . — On 2 May 1962, I discovered a nest Robert F. Andrlc BIRDS OF VERACRUZ 185 along the Lake Catemaco shore at Playa Azul, 2 m above ground on the underside of a large, horizontal tree limh. It was supported hy a large, pendent herh and was oval in shape, 17.7 cm in maximum outside diameter with a 5 cm diameter entrance on the side. The nest was thin and loosely woven of rootlets, fine twigs, and a few grasses and contained four young two or three days old. Two of these were being fed out of the nest on 22 May. This nest was considerably larger than the only one for which Skutch (1954:248) gives measurements. He remarks on the variety of nest sites chosen hy this tanager, mentioning fence post tops, palm frond, and holes in earth banks. Red-crowned Ant-Tanager (Habia riibica) . — I found a semi-pensile nest in heavy forest above Dos Amates at about 500 m altitude on 5 May 1962. It was 2 m above ground in the fork of a sapling in open understory and was constructed of grasses, rootlets, and small twigs with exterior dimensions of 10.2 hy 12.7 cm. The four eggs were white with faint brown flecks more concentrated and pronounced at the large end where they formed a wreath. One measured 25 hy 18 mm. It is of interest that neither Skutch (1954) nor Willis (1961) reported more than three eggs in the 20 nests of this species they observed. The female was still incubating in this nest on 8 May and four young about four or five days old were in it on 20 May. SUMMARY The Sierra de Tuxtla is a small, comparatively low mountain range in southern Veracruz whose rich avifauna heretofore has been investigated only in restricted areas. This paper deals with the status of nontransient birds in the entire range, covering about 4,200 square km, and lists 251 species known to have been recorded, including 55 not previously reported. The Sierra’s topography of volcanic cones, ridges, gorges, and valleys provides a varied physical base to interact with climatic elements, chief of which are trade and continental winds and northers. An important aspect of the climate is the orographic rainfall resulting from the barrier formed by the four major volcanoes and subsidiary peaks. Precipitation ranges from about 1,700 to over 4,000 mm annually, being greatest on the Gulf slopes. Although temperatures occasionally reach the freezing point at high elevations, the climate is moderated hy warm Gulf water, frequent clouds on the mountains, and extensive forests. A diverse plant cover exists owing partly to vegetation destruction and modification hy man over more than half the range. Fertile volcanic soils contribute toward a more homogeneous vegetation typified hy rain forest; this comprises one of the two most extensive habitats and supports much of the avifauna. Also supi)orting important numbers of species are large nonforested sections and water bodies, chiefly Lake Gat- emaco and Bahia Sontecomapan. The Sierra lies entirely in the Tropical Life Zone with Humid Upper Tropical and Arid divisions present, the former restricted to higher parts of the mountains and the latter to inland slopes. Boundaries of these zones are ill-defined with resj)ect to avifaunal distribution. Faunal mixing probably occurred in the Sierra during its history so that avian forms of both northern and southern affinities were represented. Since its climate was probably never cooler than warm temperate, even during the Pleistocene, it is unlikely that bird life in the range was ever completely displaced. Shifting of tropical and northern vegetation elements caused hy climatic changes also affect(‘d the avifauna. This is now composed of a large number of s|)eci(“s in Widely Distributed and Pantro|)ical elements 186 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 of unknown or uncertain origin, hut apart from this, species of prohahle southern origin predominate in comparison to those with northern affinities. The Tyrannidae, with 26 memliers, and six other families with 13 or 14 members each, comprise almost half of the avifauna. Six major avian habitats are outlined. Lists are given of the species primarily associated with each including estimates of their relative observable abundance and aproximate elevation ranges. Continuing deforestation is resulting in areal expansion and increase in total numbers of nonforest species at the expense of forest birds. The distribution and nature of plant formations largely governs altitudinal ranges of many species, and the majority normally occur below 1,000 m. Among factors influencing abundance and distribution of birds are human alterations of plant cover and flowering and fruiting of plants. The long breeding season, though having a peak period of activity, is expectedly less well defined and more prolonged than those in more northern latitudes. Differentiation of the few endemic bird species was assured in the Sierra by physical and ecological isolation. Their survival despite volcanic action was possibly aided by dispersal in both massifs and probably permitted by the restricted nature of volcanic disturbances. ACKNOWLEDGMENTS I extend my thanks to the many persons who aided jne, especially Drs. Robert C. West and George H. Lowery, Jr., of Louisiana State University, and Fred T. Hall, Director of the Buffalo Museum of Science. I am indebted to many persons in Mexico, particularly the late Ing. Luis M. Arellano, Profs. Enrique Beltran, Othon Arroniz, Carlos F. Ramirez, Raphael G. de la Cruz, and Ing. Roberto G. Gil. Dr. Velva E. Rudd, of the U.S. National Museum, and her colleagues identified my plant collections, and I also thank Drs. Harold H. Axtell, Robert W. Dickerman, Ernest P. Edwards, John W. Hardy, Byron E. Harrell, A. Starker Leopold, Walter P. Nickell, Allan R. Phillips, and Richard E. Tashian. I am grateful to L. Irby Davis, Mr. and Mrs. John Lind, Gary N. Ross, A. J. Wright, and Air. and Airs. Frederic K. Wykes for their interest and assistance. Aly 1960 work was supported by the Buffalo Society of Natural Sciences and the study in 1962 by the National Research Council of the National Academy of Sciences (Subcontract 54). LITERATURE CITED Andrle, R. F. 1966 North American migrants in the Sierra de Tuxtla of southern Veracruz, Alexico. Condor, 68:177-184. Beard, J. S. 1944 Climax vegetation in tropical America. Ecology, 25:127-158. Davis, L. I. 1952 Tropical woods. Sixteenth Breeding-Bird Census, Audubon Field Notes, 6:314-315. Dorf, E. 1959 Climatic changes of the past and present. Contrib. Mus. Paleontol. Univ. Michigan, 13:181-210. Edwards, E. P., and R. E. Tashian 1959 Avifauna of the Catemaco basin of southern Veracruz, Alexico. Condor, 61:325-337. Robert F. Audi le BIRDS OF VERACRUZ 187 Eisenmann, E. 1955 The species of Middle American birds. Trans. Linnaean. Soc. New York, 7. Friedmann, H., L. Griscom, and R. T. Moore 1950 Distributional check-list of the birds of Mexico. Pacific Coast Avifauna, No. 29. Griscom, L. 1950 Distribution and origin of the birds of Mexico. Bull. Mus. Comp. Zook, 103:341-382. Holdridge, L. R. 1947 Determination of world plant formations from simple climatic data. Science, 105:367-368. Leopold, A. S. 1959 Wildlife of Mexico; the game birds and mammals. Univ. of California Press, Berkeley, California. Loetscher, F. H., Jr. 1941 Ornithology of the Mexican state of Veracruz with an annotated list of the birds. Unpublished thesis. Cornell Univ., Ithaca, N. Y. Lowery, G. H., Jr., and W. W. Dalquest 1951 Birds from the state of Veracruz, Mexico. Univ. of Kansas Publ. Mus. Nat. Hist., 3:531-649. Lowery, G. H., Jr., and R. J. Newman 1949 New birds from the state of San Luis Potosi and the Tuxtla Mountains of Veracruz, Mexico. Occ. Papers Mus. Zool. Louisiana State Univ., 22:1-10. Mayr, E. 1946 History of the North American bird fauna. Wilson Bull., 58:3-41. Miller, A. H., H. Friedmann, L. Griscom, and R. T. Moore 1957 Distributional check-list of the birds of Mexico. Pacific Coast Avifauna, No. 33. Miranda, F., and E. Hernandez X. 1963 Los tipos de vegetacion de Mexico y su clasificacion. Bol. Soc. Bot. Mexico, 28:29-179. SCLATER, P. L. 1857ff List of additional species of Mexican birds, obtained by M. Auguste Salle from the environs of Jalapa and San Andres Tuxtla. Proc. Zool. Soc. London, Part 25:201-207. 18576 On a collection of birds received by M. Salle from southern Mexico. Proc. Zool. Soc. London, Part 25:226-230. SHELFORD, V. E. 1941 List of reserves that may serve as nature sanctuaries of national and inter- national importance, in Canada, the United States, and Mexico. Ecology, 22:100-110. Skutcii, a. F. 1954 Life histories of Central American birds. Pacific Coast Avifauna, No. 31. 1960 Life histories of Central American birds H. Pacific Coast Avifauna, No. 34. Wetmorp:, a. 1943 The birds of .southern Veracruz, Mexico. Proc. U.S. Natl. Mus., 93:215 310. Willis, E. 1961 A study of nesting ant-tanagers in British Honduras. Condor. 63:479-503. liUP’FAIA) MUSEUM OF SCIENCE, BUFFALO, NEW YOBK, 10 MARCH 1066. AGE-SPECIFIC DIFFERENCES IN THE BREEDING BEHAVIOR AND ECOLOGY OF THE AMERICAN REDSTART Millicent S. Fickex and Robert W. Fickex Maturation rates in birds are controlled by natural selection ( Lack. 1954: Orians. 1961: Amadou. 1964: Selander. 19651. Slow matura- tion rates evolved in species where there is strong intraspecific competition for food (Amadou. 1964!. species with high population densities (Orians. 1961: V ynne-Edwards. 1962 1 and in some icterid species as an outcome of a polygamous mating svstem i Selander. 1965 ) . The American Redstart I Setophaga ruticilla I has a slower maturation rate than other parulids. many males not breeding until their second spring. The purposes of this paper are ( 1 I to investigate the relationship between age of males (first-year vs. older I and type of habitat utilized, and (2) to suggest the proximate and ultimate factors responsible for the complex relationships of plumage, behavior, and ecology in this species and some other passerines. The American Redstart has an extensive breeding range and in many areas is one of the most abundant breeding birds. It is found in a variety of habitats including willow and alder thickets, deciduous, mixed decidu- ous and coniferous, and even primarilv coniferous forests ( Bent. 1953 1 . The biology of the redstart is of special interest in relation to the evolution of adaptations leading to success as measured by broad geographic range, utilization of a variety of habitats and high population density. METHODS This study was conducted in two different areas. Reproductive behavior was studied from the arrival of males until the fledging of young in a deciduous swamp forest in Ithaca. New York. This stand was dominated by a nearly closed canopy of mature deciduous trees and an understory of saplings which reached 20 feet in height. Dense stands of saplings occurred in areas where the canopy was interrupted. Redstarts occurred in both types of habitats. Information was obtained on the relative number of first-year males, their behavior, and mating success. Censuses of redstarts in a variety of habitats in Maine were conducted between 10 June and 19 June 1965. near Damariscotta (Lincoln Co.) and in the primarily coniferous forests on Mt. Desert Island (Hancock Co.). Since first-year males arrived later than older males, we selected the initial date of the census late enough to insure that all breeding males had arrived. All of the males censused behaved like territorial birds, singing loudly in a restricted area. Although we saw the mates of some birds, both first-year and older, it was not possible to determine the proportion of mated birds. 188 F'icken and Ficken REDSTART BEHAVIOR AND ECOLOGY 189 After hearing a male sing, its immediate habitat was described; then the bird was approached and its age determined on the basis of plumage. Habitats in Maine were classified in the following manner: (1) deciduous forests — some trees taller than 30 feet, an understory of saplings to 20 feet and sometimes up to 10 per cent conifers (white pine, spruce) ; (2) immature deciduous forests — tallest trees smaller than above, understory not as well developed and often more open ; ( 3 ) alder thickets — dense shrub growth usually to 15 feet in height, often with some willow and other deciduous growth; (4) mixed forest — more than 10 to 60 per cent conifers (white pine, and/or spruce), with rest deciduous; (5) coniferous forest — more than 60 per cent coniferous, including some virtually pure spruce forest. All the New York birds occurred in habitat categories 1 and 2; no effort was made to distinguish between them. OBSERVATIONS Molt and plumage. — A hand-raised male and female were observed from eight days of age until 10 months. The male obtained a few black spots on the face and breast during the first pre-alternate molt in early spring but otherwise retained a female-like plumage. This observation supports the assertion in the literature that first-year males retain a female-like plumage but generally with additional black feathers on the breast and chin, lores, cheeks, or crown (Chapman, 1907). Unfortunately we were unable to follow this male through the pre-basic molt in the fall, but according to Chapman (1907) the adult male plumage is attained at this time. The possibility remains that some first-year males molt into adult plumage at their first pre- basic molt or that some males are delayed beyond the end of their first breeding season in attaining adult male plumage. Ossification of the skull progresses more slowly in the redstart than in most other parulids ( S. Eaton, pers. com.). David Bridge (pers. com.) reports that there are rare cases of males in immature plumage during the fall migration which had com- pletely ossified skulls, indicating that at least some males do not attain adult male plumage until their third pre-basic molt. However, for the purpose of this study, we term males with a female-like plumage “first-year.” They are easily distinguished from females in the field by the presence of a few black spots. Eirst-year females in the spring often show less yellow in the wing than older females (Chapman, 1907) and our captive l)ird also had less vellow on the sides of the breast. Birds with these characters which were observed in the field were considered to be first-year females. However, it is not known if all first-year females have this j)lumage or if older females also sometimes do. 190 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Time of arrival on territory. — The usual order of arrival, although there was some overlap, was older males, older females and first-year males. The arrival time of first-year females was less certain but some arrived after the first-year males. The delay between the mean arrival date of the older males and first-year males was about two weeks in both New York and Maine. Territorial behavior. — Redstarts are very aggressive and maintain rather rigid territories, tolerating no intrusion by conspecific males ( Licken, 1962a ) . Displays and fighting are common. The redstart is more aggressive than several other parulids which we studied [Dendroica petechia, D. pensylvanica, D. virens, Vermivora pinus, and V. chrysoptera) (Licken and Licken, 1965). In New York, older males first settled on territories in tracts of mature forest. Later, when first year males arrived, only peripheral areas, usually where the forest was open and low in stature, were available. The young males were usually restricted to these peripheral habitats by the aggressiveness of the older males. Older males appeared to be more aggressive than the young; they always won encounters with younger males. Territory size. — Little is known about the territory size of first-year males as compared to older males. However, in the New York study area we found that the territory size of the two age classes was not markedly different, ex- cept that the smallest territory observed belonged to a first-year male. Hickey (1940 ) also noted that the territory size of the two age classes was similar. Redstart territories are quite small when compared to those of other war- blers (Mayfield, 1960) even those coniferous forest species during spruce bud worm outbreaks (Kendeigh, 1947). In our New York study area they averaged about 0.75 acres, and Hickey (1940) reports territories were one acre or less on a “heavily wooded slope” in Westchester County, New York. Sturm (1945) found very small territories; one group in a second growth deciduous forest averaged 0.24 acre and another 0.16 acre. Thus deciduous woodlands with much second growth appear to be optimal lor the species as such habitats support the maximum population densities. However, most territories in mixed and coniferous forests in Maine were over an acre in size and even in the deciduous habitats many males were isolated or had only one neighboring male in an area of several acres. Mating success. — All older males (52) in our New York study area ob- tained mates while only three out of 7 ( 43 per cent ) first-year males did so (Licken, 1962a). Similarly, Sturm ( 1945) noted that only three out of 5 (60 per cent ) first-year males were mated in an Ohio woodland. However, the four first-year males studied by Hickey (1940) obtained mates. In our New York study area, first-year males that did not obtain mates remained only about two weeks on territory, then left. Floaters. — In other species of warblers it has been shown that there is a Fickcii and Ficken REDSTART BEHAVIOR AND ECOLOGY 191 population of non-breeding males which will occupy territories when space is available (Stewart and Aldrich, 1951; Hensley and Cope, 1951). First- year male redstarts are sometimes ‘‘floaters,” at least in deciduous woodlands. We have on several occasions seen unmated males in sub-optimal habitats in June. Each was there for a few days and usually silent or singing only muted song fragments. Hickey (1940) reports a first-year male that was singing softly and was “furiously driven off by males and females whenever it passed through their territories.” Some of these floaters may not have found suitable areas for the establishment of territories because of the aggressive- ness of older males. Others may have abandoned territories when they did not obtain mates. There is also the possibility that some first-year males do not even attempt to set up territories but are floaters from the start. Nesting success. — We did not obtain quantitative data on nesting success in the two age classes but have a few observations which show that pairs of first-year birds are less successful. One such pair constructed and subse- quently abandoned seven nests, at least twice after the female had begun incubation. Finally, this pair left the area in late July and presumably made no further breeding attempts that year. The cause for the nest abandonments was not known, but this behavior was not noted in older pairs. The nest of another first-year female was blown away by winds that destroyed no other nests in that area. This was probably due to its insecure anchorage, since the female had selected a two-pronged rather than a typical three-pronged crotch < Ficken, 1964 ) . Foraging behavior. — It is generally agreed that redstarts prefer deciduous woodland with a good undergrowth of bushes and young trees (Chapman, 1907; Bent, 1953; Griscom and Sprunt, 1957). Redstarts forage at medium elevations, usually between 10 and 30 feet, hut occasionally near the ground or on low herbaceous plants ( Ficken, 19625 ) . Insects are obtained by glean- ing, hovering, and flycatching. Flycatching makes up over 80 per cent of the foraging patterns before the leaves are out in May, hut the other patterns are more prevalent as the season progresses. Relation oj age and habitat. — The relative number of first-year territorial males in deciduous woodlands in New York and Ohio is surprisingly small, averaging 12 per cent in the three studies with large samples of birds (Table 1). Table 2 shows the incidence of first year males in a variety of Maine habitats. Deciduous forests in Maine contain a higher percentage of first- year males than do deciduous forests in New York and Ohio hut are com- })arable to the findings for Michigan. There are differences in the frecpiencN of first-year males in different habitats in Maine. First-year males are least common in alder thickets and relatively mature deciduous forests and more common than older males in immature deciduous. mi\(‘d. and coniferous 192 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 forests. The difference between the number of first-year males in deciduous and mixed forests is statistically significant (P<0.05) while that between alder and deciduous is not ( P > 0.05 ) . Numbers were insufficient for a statistical analysis of mixed vs. coniferous and deciduous vs. immature de- ciduous forests. The distribution of the two age classes of redstarts in Maine habitats ap- pears to be related to the amount of deciduous foliage. Habitats which have a high deciduous foliage density in the vertical foraging range of the redstart are alder and mature deciduous. Immature deciduous (often more open I and mixed woodlands are intermediate. Of course, forests consisting of more than 60 per cent conifers have the lowest deciduous foliage density. The frequency of first-year males parallels this foliage density, being higher where the deciduous foliage density is lower. MacArthur et al. (1962) suggested that species abundance in birds is related to the foliage density of vegetation in deciduous forests and this example shows that age classes within a species may also be so related. DISCUSSION Our hypothesis is that originally, before the evolution of a special plumage, first-year males had lower reproductive success than older males. Such a situation exists in many birds and is probably widespread (e.g., Nice, 1937; Snow, 1958; Coulson and White, 1958; Wynne-Edwards, 1962). For ex- ample, in Song Sparrows [Melospiza rnelodia) first-year males often arrive later than older males, are less aggressive, and in many cases their females lay fewer eggs than older ones (Nice, 1937). With intense intraspecific competition, those individuals which were the least efficient would produce too few young to balance the “expense” of breeding. Selection would favor a system for lowered reproduction in young birds if this led to enhanced reproductive success in subsequent years. The first evolutionary step is probably the establishment of a hormonal mecha- nism. Some support for this is found in studies of Red-winged Blackbirds {Agelaiiis plioeniceus). Testes of first-year males, which usually do not breed, attain their maximum development three weeks after older males. Also their maximum size is only two-thirds that of older males, although they do undergo spermatogenesis ( Wright, 1944 ) . A lowered hormone level and a delay in testes development might have many effects in first-year birds in- cluding lowered aggressiveness, later arrival on the breeding grounds and retention of a female-like plumage. In many species molt into breeding plumage is at least partly controlled by androgens (Witschi, 1961). Miller (1933) suggested that the great vari- ability in melanin deposition in first-year male Phainopeplas ( Phainopepla Ficken and Fieken REDSTART BEHAVIOR AND ECOLOGY 193 Table 1 Percentage of Territorial First-Year Males in Deciduous Habitats Per cent territorial first-year males Total number of males Habitat Reference 12 59 deciduous — N. Y. Ficken, 1962a 0 10 mixed— N. Y. Kendeigh, 1945 8 48 deciduous — N. Y. Hickey, 1940 29 7 deciduous — Mich. Baker, 1944 15 34 deciduous — Ohio Sturm, 1945 nitens ) was due to a variable amount of testicular hormone at the time of the molt. The possession of a female-like plumage in first-year males which do not breed probably has not been selected for directly but is the outcome of selection for slower maturation ( Orians, 1961 ) . The plumage of the first- year male redstart seems to confer no direct advantage in the competitive situation with older males since first-year males are reacted to just as aggres- sively as older males. Male redstarts also react very aggressively toward females initially (Ficken, 1963) and this again illustrates that a female-like plumage is reacted to aggressively. Since first-year males sing, this probably enhances their aggressive releasers as compared to females. In Orchard Orioles [Icterus spuriiis) which also have a female-like plumage their first year ( but it is not known what proportion of first-year males breed ) fights between first-year and older males are intense, although the species is in general non-territorial (Dennis, 1948). Thus, first-year male plumage in this species as well apparently does not reduce aggression by other males. It might be expected that it would be advantageous for floaters not to be re- acted to aggresively by other males, but as Hickey (1940) observed, redstart floaters are attacked despite their plumage. However, a female-like plumage is much more cryptic than the red and black of the adult male, at least to the human observer, and this crypticity might be of value in reducing predation on first-year males. Later arrival may lead either to failure to procure a mate or to mating with first-year females. Since first-year males arrive later than most females, mating may be partly a matter of availability of females at the time of arrival of males. However, other factors are probably involved. Females may not be as sexually responsive to males in a female-like plumage. Also the lowered aggressiveness of first-year males may reduce chances of pairing since an initial strong aggressive response of the male toward the female ma\ be necessary for pair formation to occur in this species (Ficken. 1963). Late arrival may contribute to the inability of first-year males to compete successfully with older males in several wavs. One is that often all suitable ]94 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Table 2 Frequency of Territorial First-Year Male Redstarts in a Variety OF Habitats in Maine Habitat Total no. of males No. of first- year males Percentage of first-year males Alder 14 1 7 Deciduous 14 3 21 Immature deciduous 7 5 71 Mixed coniferous-deciduous 15 9 60 Coniferous 11 9 82 territories are occupied. Another is that all older males are recently mated and territorial aggressiveness seems to reach its peak at just that time ( Ficken, 1962a ) so they are likely to be more aggressive to first-year males than they were to each other initially. The reduced aggressiveness of the first-year males probably also affects their ability to obtain suitable territories. Experience plays a part in success in aggressive encounters of many animals (Scott, 1958), and lack of experi- ence probably reduces success in encounters between first-year and older male redstarts. The inability to compete successfully with older males prob- ably leads to some wandering and males either become floaters or sub- optimal habitats are found and territories are established there where com- petition with other males is reduced or absent. First-year male redstarts are more often found in late spring outside their normal breeding range in Cali- fornia than are older males ( Root, 1962 ) , indicating that the young males are probably the pioneers in range and habitat extensions. The utilization of sub- optimal habitats probably reduces breeding success further. One way may be through reduction of the amount of food available since the deciduous foliage density is lower. In some species choice of a mate by the female is at least partially determined by the quality of the habitat of potential mates (Verner, 1963; Tompa, 1962). If this is true in the redstart, mating success will be further reduced by the possession of territories in sub-optimal habitats. Thus the ultimate cause of the interrelated effects of female-like plumage, low reproductive success, less aggressive behavior and utilization of sub- optimal habitats is selection against breeding of what were originally slightly less successful birds. The question naturally arises as to why first-year males attempt to breed at all. However, if they breed where they are not competing with older males, and even some small fraction is successful, this would be ad- vantageous. Also, there may be much learning necessary for reproductive success. By attempting to breed or just getting through some of the stages Ficken and Ficken REDSTART BEHAVIOR AND ECOLOGY 195 of breeding, first-year males may have a better chance for breeding in sub- sequent years as a result of this experience ( Selander, 1965 ). Many aspects of the redstart system are not unique. Wynne-Edwards ( 1962) has pointed out that slow maturation rates are often found in species with high population densities. However, he postulates a system based on group selection while it probably can best be explained by natural selection at the individual level ( Amadon, 1964; Selander, 1965 ), as a result of the system older and more experienced breeders having reduced competition for territories. Orians (1961) studied the population structure of blackbirds [Agelaius phoeniceus and A. tricolor) and extended his conclusions to other species as well. He suggested that slow maturation of first-year males is “characteristic of species in which breeding sites are limited. Probably these are all species which are ineffectively controlled between breeding seasons so that surpluses of breeding birds are regularly present.” Selander ( 1965 ) , from his studies of polygamous Cassidix species suggests that “be- cause the probability of a young male obtaining mates in competition with older experienced males is very low, males which postpone breeding may ultimately have greater reproduction; and through selection first-year males have become adaptively ‘handicapped’ physiologically and morphologically in competition with adult males for mates.” Delayed maturation occurs in some icterids ( Orians, 1961 ; Selander, 1965) and although in some cases it seems to be associated with a high population density the situation is further complicated by the type of mating system, delayed maturation being more common in non-monogamous species, although this is probably a consequence rather than a cause of delayed maturation (Selander, 1965). For example, delayed maturation occurs in the grackles Cassidix major and C. mexicanus which have a plumage intermediate between the juvenile-female and the adult male, and the males do not breed until their second year (Selander, 1965). The Red-winged Blackbird (Agelaius phoeniceus), the Tricolored Blackbird (A. tricolor], and the Yellow-headed Blackbird (Xanthocephalus xanthocephalus) bave delayed maturation, are colonial with high breeding densities and breeding sites are at a premium in some localities. Male Red-winged Blackbirds do not normally breed until two years of age, although first-year males may occur at the periphery of the colony. Some obtain territories and a few breed. In the Tricolored Blackbird yearling males regularly establish ter- ritories, but as in the redstart they are crowded into the less desirable sites and are less successful in obtaining mates (Orians, 1961). Orians’ hypothesis of a relationshij) between high breeding po|)ulation densities and delayed maturation seems to be a|)plicable to eases where there is little information available on breeding behavior. For exam|)le. a dela\ 196 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 in attaining adult male plumage occurs in the Orchard Oriole [Icterus spurius) but not in the Baltimore Oriole (/. galbula) , and the Orchard Oriole seems to have intense intraspecific competition in some areas. For example, Dennis (1948) reports that males of this species are not territorial and one population which he studied attained a density of 114 males in 7 acres, with as many as 20 nests in one tree. The femaledike plumage of first-year male crossbills Loxia curvirostra and L. leucoptera may also be related to locally high population densities in these semicolonial breeders. First-year male Purple Martins [Progne subis ) differ in plumage from older males. This species nests in colonies, and there is probably also a shortage of nest sites. The species with delayed maturation which we have discussed are those in which there is a color difference between the age classes and non-breeding first-year males are more noticeable. However, there are cases such as that noted by Selander ( 1964) where some species of the wren genus Campylorhyn- clius breed the first year while others do not. Whether this is related to breed- ing population densities and intraspecific competition is not known. The evolution of delayed maturation rates in birds might be expected more commonly in species with a long life span as is the case with certain sea birds, many of which do not breed until they are several years old (e.g., Wynne-Edwards, 1962 ). These species also often have high population den- sities. In such species the enhancement of breeding success in older birds by reduced competition with younger ones would occur over several breeding seasons, although there are undoubtedly many other variables influencing their reproductive success. However, it is probably not surprising that rela- tively few of the small passerines, with their relatively short life span, have evolved such a system. Our findings also have implications for studies of habitat “preference.” The habitat difference between first-year and older males is obviously not innate. However, in the species as a whole there is probably an innate basis, although with learning also involved, for responding only to certain types of habitats. Even first-year males are selective, and are not found breeding in just any habitat. It is misleading to refer to a “preference” or “selection” in the case of first-year redstarts. They often seem to initially occupy habitats where older males are also breeding but through competition must go elsewhere. It would seem advantageous for a species to be somewhat flexible and to be able to respond to a variety of habitats ( Svardson, 1949). Thus the redstart has evolved a system of interrelated physiological, be- havioral, and ecological adaptations which are related to intraspecific com- petition and to its extensive and diverse geographic range and which con- tribute to making it one of the most successful North American passerines. Ficken and Fickcn REDSTART BEHAVIOR AND ECOLOGY 197 Other species with intense intraspecific competition may have similar systems, although differing in some respects from that proposed for the redstart. SUMMARY First-year male American Redstarts are relatively uncommon as compared to older males as breeders in deciduous forests in the eastern and central United States. How- ever in Maine they occur more frequently than older males in suh-optimal habitats. In New York first-year males arrive later than older males, are less aggressive and consequently at a disadvantage in competing with older males for territories in optimal habitats. They are also less successful in obtaining mates, at least partly due to their later arrival. A system is proposed to explain the interrelated effects of a female-like plumage, late arrival, lowered aggression, and use of sub-optimal habitats. It is sug- gested that delayed maturation, probably involving a lowered androgen level, evolved as a result of intense intraspecific competition in this species, and that selection acts against first-year males breeding in optimal habitats. Other passerines in which first- year males differ in plumage from older males also have high population densities and were probably subjected to similar selective pressures. ACKNOWLEDGMENTS This study was aided financially by a Sigma Xi Grant-in-Aid and by National Science Foundation Grant GB-3226. We wish to thank Douglass H. Morse and Richard Root for their criticisms of the manuscript and Stephen Eaton and David Bridge for their unpublished data. LITERATURE CITED Amadon, D. 1964 The evolution of low reproductive rates in birds. Evolution, 18:105-110. Baker, B. W. 1944 Nesting of the American Redstart. W ilson Bull., 56:83-90. Bent, A. C. 1953 Life histories of North American wood warblers. V.S. Natl. Mus. Bull., 203. Chapman, F. M. 1907 The warblers of North America. Appleton and Co., New \ork. CoULSON, J. C., AND E. WlIITE 1958 The effect of age on the breeding biology of tbe Kittiwake Hissa tridactyla. Ibis, 100:40-51. Dennis, J. V. 1948 Observations on the Orchard Oriole in lower Mississippi delta. Bird-Banding. 19:12-21. Ficken, M. S. 1962r/ Agonistic behavior and territory in the American Redstart. Auk, 79:607-632. 19626 Maintenance activities of the American Redstart. WA'lson Bull., 74:153 165. 1963 Courtship of the American Redstart. Auk, 80:307-317. 1964 Nest-site selection in the American Redstart. W ilson Bull., 76:189. Ficken, M. S., and R. W. Ficken 1965 Comparative ethology of the Yellow Warbler, (4iestnut-sided Warbler and American Redstart. W' ilson Bull., 77:363-375. 198 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 (/HISCOM, L., AND A. SpRUNT 1957 The warblers of America. Devin-Adair Co., New ^ork. Hensley, M. M., and J. B. Cope 1951 Further data on removal and repopulation of the breeding birds in a spruce- fir forest community. Auh, 68:483-493. Hickey, J. J. 1940 Territorial aspects of the American Redstart. Auk, 57:255-256. Kendeigh, S. C. 1945 Nesting behavior of wood warblers. WAlson Bull., 57:145-164. 1947 Bird population studies in the coniferous forest biome during a spruce bud- worm outbreak. Biol. Bull. No. 1, Dept, of Lands and Forests, Ontario, Canada. Lack, D. 1954 The natural regulation of animal numbers. Oxford Lniv. Press, Oxford. MacArtiiur, R. H., j. W. [MacArthur, and J. Freer 1962 On bird species diversity. II. Prediction of bird census from habitat measure- ments. Amer. Nat., 96:167-174. Mayfield, H. 1960 The Kirtland’s Warbler. Cranbrook Inst. Science, Bloomfield Hills, Michigan. Miller, A. H. 1933 Postjuvenal molt and the appearance of sexual characters of plumage in Phainopepla iiitens. Unit. California Puhl. Zool., 38:425-446. Nice, M. M. 1937 Studies in the life history of the Song Sparrow\ I. Trans. Linnaean Soc. New York. Orians, G. H. 1961 The ecology of blackbird iAgelaius) social systems. Ecol. Monogr., 31: 285-312. Root, R. B. 1962 Comments on the status of some western specimens of the American Red- start. Condor, 64:76-77. Scott, J. P. 1958 Aggression. Univ. Chicago Press, Chicago. Selander, R. K. 1964 Speciation in wrens of the genus Campylorhynchus. Univ. California Publ. Zool, 74:1-289. 1965 On mating systems and sexual selection. Amer. Nat., 99:129-141. Snow, D. W. 1958 The breeding of the Blackbird Turdus merula at Oxford. Ibis, 100:1-30. Stewart, R. E., and J. W. Aldrich 1951 Removal and repopulation of breeding birds in a spruce-fir forest community. Auk, 68:471-482. Sturm, L. 1945 A study of the nesting activities of the American Redstart. Auk, 62:189-206. Syardson, G. 1949 Competition and habitat selection in birds. Oikos, 1:157-174. Tompa, F. S. 1962 Territorial behavior: the main controlling factor of a local Song Sparrow population. Auk, 79:687-697. Ficken ami Ficken REDSTART BEHAVIOR AND ECOLOGY 199 Verner, J. 1963 Song rates and polygamy in the Long-billed Marsh Wren. Proc. 13th Internatl. Ornith. Congr., 299-307. WiTSCHI, E. 1961 Sex and secondary sexual characters, p. 115-168. In: Marshall, A. J. (ed.). Biology and comparative physiology of birds. Academic Press, New York. Wright, P. L., and M. H. Wright 1944 The reproductive cycle of the male Red-winged Blackbird. Condor, 46:46-59. Wynne-Edwards, V. C. 1962 Animal dispersion in relation to social behaviour. Oliver and Boyd, Edin- burgh. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MARYLAND, COLLEGE PARK, MARY- LAND, 5 FEBRUARY 1966. JOSSELYN VAN TYNE MEMORIAL LIBRARY The following gifts have been recently received. From: Oliver L. Austin, Jr. — 1 journal Andrew J. Berger — 3 reprints C. T. Black — 40 journals, 5 reprints R. K. Brooke — 3 reprints George A. Clark, Jr. — 2 reprints C. T. Collins — 3 reprints Earle R. Greene — 1 book Alfred 0. Gross — 25 reprints George A. Hall — 1 journal Doris C. Hauser — 6 reprints F. Haverschmidt — 1 journal J. J. Hickey — 1 book George Hunt — 2 pamphlets D. J. T. Hussell — 6 journals, 10 reprints David W. Johnston — 2 reprints Alice H. Kelley — 1 pamphlet Leon Kelso — 4 hooks, 1 journal, 22 transla- tions S. C. Kendeigh — 2 reprints R. C. Lasiewski — 1 reprint Amelia R. Laskey — 3 reprints James P. Ludwig — 3 reprints Daniel McKinley — 8 reprints Harold Mayfield — 15 reprints R. E. Morrill — 7 books B. G. Murray, Jr. — 1 reprint Margaret M. Nice — 5 journals, 60 reprints Ralph S. Palmer — 1 translation, 1 reprint C. Chandler Ross — 16 books, 11 reprints R. M. Schramm — 12 journals Charles G. Sibley — 1 reprint A. M. Simonetta — 3 reprints W. E. Southern — 1 reprint Robert W. Storer — 1 book Mrs. Josselyn Van Tyne — 3,300 reprints L. R. Wolfe — 1 book, 32 journals, 4 pam- phlets, 62 reprints John L. Zimmerman — 2 reprints AN EC01,0GICAL STUDY OF WINTER FLOCKS OF BLACK- CAPPED AND CHESTNUT-BACKED CHICKADEES Susan M. Smith Most living species have developed special adaptations A\hich enable them to fit into a particular mode of life, or niche. Two closely related species are very likely to have similar structural features, behavioral responses, and so on. which lead to correspondingly similar ecological re- quirements. The more closely related two symatric species are, the more need there will be for differences to evolve which will keep their modes of life separate and prevent overlap of requirements. Ecological isolation is important to closely related avian species for two reasons. By avoiding niche overlap, interspecific competition is practmally eliminated. Secondly, ecological isolation reduces the possibility of hybridiza- tion. As hybrids tend to have reduced viability and will be poorly adapted to either parental niche, hybridization, as shown by many writers, is selected against. Several differences have evolved among closely related sympatric passerines which aid in preventing ecological overlap. Differences in anatomy such as the leg muscles of the Goldcrest ( Regiihis regulus I and the Willow Tit ( Parus montanus) I Palmgren, 19321. or the beak shape of Eurasian tits (Snowy 195461 prevent overlap of feeding niche. Differences in color, voice, and behavior (especially reproductive behavior I also serve to separate closely related species. Peterson, Mountfort. and Hollom (19541 list nine species of the genus Parus in Europe, six of which occur in Great Britain. Many of these are sympatric over much of their range. European studies on the comparative ecology of these titmice have shown that each of them has evolved its separate niche enabling it to live in close contact with other tit species, >et at the same time avoid serious interspecific competition (Gibb, 1954; Haftorn, 1956: Hartley, 1953: Snow. 1954u, 19546; and others). Xearctic titmice have not developed nearly this degree of SYinpatr). Hoi\- ever, along the Pacific coast of North America the ranges of the Black- capped Chickadee i Parus atricapillus) and the Chestnut-backed Chickadee [Parus rufescens) overlap. In describing the habitat of the Black-capped Chickadee in California, Grinnell and Miller ( 1944 ) write “Chiefly deciduous timber, especially willows and alders, along large or small water courses.” Gabrielson and Jewett (1940) write of it in Oregon: “. . . The Oregon Chickadee replaces the Chestnut-backed Chickadee in the cottonwood bot- toms.” Jewett, Taylor, Shaw and Aldrich (1953) write of it in Washington: “Tree alders and deciduous woods are favorite foraging grounds ...” 200 Susan M. Sinitli CHICKADEE WINTER ECOLOGY 201 The habitat of the Chestnut-backed Chickadee seems to be somewhat dif- ferent. Grinnell and Miller (1944) describe its habitat in California as “Coniferous forest and adjacent woodland.” Jewett et al. (1953) write of it in Washington: “While preferring the dense shade of the coniferous forests of the Pacific coastal belt to any other habitat, the chestnut-backed chickadee is found rather broadly through the timbered sections . . . ordinarily it re- mains high in the trees . . .” While these descriptions indicate a general difference in the habitat of these two species, no more specific analysis of this seems to have been made. In Vancouver, British Columbia, it is possible to find both of these species living side by side. They even forage in mixed flocks during the winter. This study has been conducted on winter flocks of these species in an attempt to find factors producing ecological isolation between them. Field work was carried out on an area of mixed second growth forest adjacent to the University of British Columbia campus, and covering ap- proximately 0.75 square miles. The vegetation of the area can be classified as the wet subzone of the Coastal Douglas Fir Zone, with transitional char- acteristics of the Coastal Western Hemlock Zone (Krajina, pers. comm.). Based on a strip survey made on a portion of the study area, the vegetation is 55.4 per cent deciduous and 44.6 per cent coniferous. The main conifers are Douglas-fir iPseudotsuga menziesii) , western hemlock {Tsug,a heterophylla) , red cedar {Thuja plicata), and grand fir {Abies grandis). Broad-leafed maple {Acer macrophyllum) and red alder {Alnus rubra) make up virtually all the deciduous trees on the area, and the main shrubs are redberry elder iSambucus pubens), thimbleberry and salmonberry {Rubus spp. ) . Observations were made at least once weekly, for two to four hours each time, from 21 September 1962 to 15 March 1963. When a flock of chickadees was found, its size and composition were noted. A separate record was made for each feeding chickadee including the following information: species, height above ground, height and species of feeding site, and position within the feeding site. RESULTS Although feeding in the same area, individuals of the two species showed definite differences in selection of feeding sites. One of the main differences was in the type of tree chosen (Table 1). There are slightly more than 3.5 times as many records of Black-capped Chickadees in deciduous as in conif- erous trees, while there are more than five times as many records of Chestnut- hacked Chickadees in coniferous as in deciduous trees. The second major difference in the feeding behavior of the two species was found to be in the choice of height of the feeding site. Figure 1 shows 202 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Frequency Table 1 OF Records in the Three Main Feeding Sites Black-capped Chickadee Chestnut-backed Chickadee Coniferous trees 21.0 per cent 84.1 per cent Deciduous trees 76.4 per cent 15.9 per cent Ground 2.6 per cent Number of records: 598 327 the percentages of each species’ records at various distances above the ground. This shows a definite separation of the two species. The peak of the Black- capped Chickadee records occurs at the 0-5 foot class, and no Black-capped Chickadee was recorded above 70 feet: while the peak of the Chestnut-backed Chickadee records occurs at the 45-50 foot class, and 12.0 per cent of the records are for above 70 feet. Application of the Student’s t-test has shown these peaks to be significantly different at the 0.01 level. Figure 2 shows the percentage of records of each species at various distances from the top of the feeding site. In this figure no records of birds in Rubus spp. were included, since these shrubs are seldom over five feet hish. so that virtually all records for these sites would fall in the class of five felt or less from the top of the site. As seen from the figure, there is very little difference between the two species in this respect, although a slightly larger percentage of Chestnut-backed (28.9 per cent) than of Black-capped ( 22.0 per cent ) Chickadees was found five feet or less from the top of the feeding site. During the study, flocks of chickadees were frequently observed travelling at a fairly uniform height above ground, often seemingly regardless of the height of tree through which they were passing. Thus in this study area this factor is possibly of less value in maintaining ecological isolation between the two species than is the height above ground. Table 2 shows the percentage of records of each species with regard to their position within the tree. Both species spent the majority of their time in the thin outer twigs of trees. However, Chestnut-backed Chickadees were seen foraging on “thick” ( i.e. two inches or more in diameter) branches less often than were Black-capped Chickadees, while 4.1 per cent of the records of Black-capped Chickadees are for gleaning on the main trunk, but there are no records of Chestnut-backed Chickadees gleaning on this position. Both species were seen feeding on conifer seeds directly from the cones m western hemlocks and Douglas-firs: these records were considered as “thin branches in Table 2. “Mixed flocks” (those containing both species of chickadees moving to- aether I were commonly seen during the study, being observed on all but Susan M. CHICKADEE WINTER ECOLOGY 90S Smith HEIGHT (feet) Fig. 1. Comparison of feeding heights of Black-capped and Chestnut-backed chicka- dees. five days. The average mixed flock consisted of 11.8 Black-capped and 7.7 Chestnut-lDacked chickadees. The average number of chickadees in a pure flock of Black-capped Chickadees was 8.7, and the average number in a pure flock of Chestnut-backed Chickadees was 8.T. Thus it seems likely that mixed flocks are relatively unstable units made up of two chickadee flocks. Neither species seemed to be influenced by the presence or absence of members of the other species, in either their choice of type or of height of feeding site. No significant difference between pure and mixed flocks was found in either consideration. Very little aggression of any kind was observed during this study. In- traspecific aggression was observed three times among Black-capped Chicka- dees, and only once among Chestnut-backed Chickadees. However, at no time during the study period was any aggression observed between the two chickadee species. During the study period no extremes in weather occurred. I here was no correlation between the date of the records and the average height of the records, or of choice of type of feeding site. 204 THE WILSOX BULLETIX June 1967 Vol. 79. No. 2 DISTANCE FROM TOP OF TREE (feet) Fig. 2. Comparison of distance from top of feeding site of Black-capped and Qiest- nut-backed chickadees. DISCUSSION There are seven species of chickadees, i.e. members of the subgenus Poecile of the genus Parus (Dixon. 19611 in Xorth America. Lnlike the palearctic parids, most of these are allopatric. the most notable exception being the sympatry of the Black-capped and Boreal ( P. hudsonicus i chickadees. These two species are the only Xorth American chickadees with continent-wide range, and there is a broad overlap in their occurrence. Lack ( 19441. Dixon 1 1954. 1961 1, and others have stressed the importance of adjustments in behavior, especially feeding behavior, if two similar forms are to coexist in the same area. Dixon 1 1961 1 writes that the Boreal Chicka- dee is reported to forage higher in the trees than the Black-capped Chickadees Susan M. Smith CHICKADEE WINTER ECOLOGY 205 Frequency of Table 2 Records at Various Positions Within the Tree Trunk Thick branches Thin branches Black-capped Chickadee 4.1 per cent 2.8 per cent 93.1 per cent Chestnut-backed Chickadee — 1.2 per cent 98.8 per cent do. He also shows that there are marked differences in the habitat preferences of these two species, and he suggests that this is their principal means of ecological isolation. Most writers agree that the preferred habitat of the Black-capped Chickadee is open deciduous or mixed forest. On the other hand, the Boreal Chickadee, like the Chestnut-backed Chickadee, is most numerous in moist shaded coniferous forest (Dixon, 1961). This similarity of habitat choice between the Chestnut-backed and Boreal chickadees was a major factor in Grinnell’s (1904) postulating that they both arose from a common ancestor which he named Parus prehudsonicus. Apart from the Black-capped and the Boreal chickadees, the pair with the greatest range overlap seems to be the Black-capped and the Chestnut-backed chickadees, for the former occurs over much of the latter’s range. In this study it was found that in winter flocks of these two species there are marked differences in feeding behavior, which are very similar to those observed between the Black-capped and Boreal chickadees. Dixon (1961) writes that the Black-capped and Boreal chickadees seem to have achieved the closest approach to “ecologic compatibility” of any pair of North American chicka- dees. The data of this study suggest that a similar ecologic compatibility exists between the Black-capped and the Chestnut-backed chickadees, which is achieved by essentially the same differences, i.e. tree species selection and height selection of the feeding sites. This separation is naturally augmented by differences in color and in voice. It is interesting to note that the tone of the Boreal Chickadee is reported to be very similar in quality to that of the Chestnut-backed Chickadee. It cannot be said from these data that there is competitive exclusion or habitat adjustment as a result of overlap in range of these species. These differences in feeding habits probably do apply equally well to areas where only one of these two species occurs. Studies on Chestnut-backed Chickadees on Pacific coastal islands such as Vancouver Island ( vvhere no Black-capped Chickadees occur ) may throw some light on this matter. More work is also necessary to find out whether these differences occur during other seasons of the year. Nevertheless, these differences may well be the major factors which allow stable range overlap of these two species. 206 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 SUMMARY W inter flocks of Black-capped and Chestnut-hacked chickadees were studied in an attempt to find factors producing ecological isolation between the two species. Two major differences were observed between these chickadees. Although the study area woods were approximately 50 per cent deciduous and 50 per cent coniferous, 76 per cent of the feeding records of Black-capped Chickadees were in deciduous trees, while 83 per cent of the Chestnut-backed Chickadee records were in coniferous trees. Secondly, the peak of records of Black-capped Chickadees was between 0 and 5 feet above the ground; that of Chestnut-hacked Chickadees was between 45 and 50 feet above the ground. Black-capped Chickadees were recorded foraging on thick branches and main trunks slightly more often than were Chestnut-hacked Chickadees. Black-capped Chickadees were also recorded feeding on the ground in 2.5 per cent of the records: there were no records of Chestnut-backed Chickadees feeding on the ground. Being in mixed flocks had no significant effect on either species, for any measured variable. No interspecific aggression was observed. It is suggested that the differences between the two species' choice of kind and height of feeding site are major factors in maintaining ecological isolation between these species in areas of sympatry. ACKNOWLEDGMENTS I am grateful to Dr. M. D. F. Udvardy, for his suggestions on the problem as well as his criticism of the manuscript. Thanks are also due to Dr. V. Krajina and Dr. L. Orloci for information on the vegetation of the study area, and advice on the methods of its survey. In addition I would like to thank Dr. D. H. Chitty for ideas derived from personal communications. LITERATURE CITED Dixon, K. L. 1954 Some ecological relations of chickadees and titmice in central California. Condor, 56:113-124. 1961 Habitat distribution and niche relationships in North American species of Parus. In : Vertebrate Speciation. a University of Texas Symposium. W. F. Blair, Ed. University of Texas Press, Austin. Gabrielson. I. N., AND S. G. Jewett 1940 Birds of Oregon. Oregon State College Press, Corvallis. Gibb. J. 1954 Feeding ecology of tits, with notes on Treecreeper and Goldcrest. Ibis, 96:513-543. Grinnell, J. 1904 The origin and distribution of the Chestnut-hacked Chickadee. Auk. 21:364- 382. Grinnell, J.. and A. H. Miller 1944 The distribution of the birds of California. Pacific Coast Avifauna, 27:1-608. Haftorn, S. 1956 Contribution to the food biology of tits especially about storing of surplus food. Part IV. A comparative analysis of Parus atricapillus L., P. cristatus L. and P. ater L. Xorsk. J'idensk. Selsk. Skr., 4:1-54. Susan M. Smith CHICKADEE WINTER ECOLOGY 207 Hartley, P. H. T. 1953 An ecological study of the feeding habits of the English titmice. J. Anim. EcoL, 22:261-288. Jewett, S. G., W. P. Taylor, W. T. Stiaw, and J. W. Aldrich 1953 Birds of Washington State. University of Washington Press, Seattle. Krajina, V. J. 1959 Bioclimatic zones in British Columbia. University of British Columbia Botanical Series, No. 1. Lack, D. 1944 Ecological aspects of species-formation in passerine birds. Ibis, 86:260-286. Palmgren, P. 1932 Zur Biologic von Regulus regii/ns regulus Linnaeus und Petrus atricapillus Selys. Eine verglichend-okologische Untersuchung. Acta Zoologica Fennica, 14:1-113. Peterson, R. T., G. Mountfort, and P. A. D. Hollom 1954 A field guide to the birds of Britain and Europe. Collins, London. Snow, D. W. 1954« Trends in geographical variation in palearctic members of the genus Pants. Evolution, 8:19-28. 19546 The habitats of Eurasian tits ( Pants spp.). Ibis, 96:565-585. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER 8, BRITISH COLUMBIA, CANADA. (PRESENT ADDRESS: DEPARTMENT OF ZOOLOGY, UNIVERSITY OF VFASHINGTON, SEATTLE, WASHINGTON 9810,5), 31 JANUARY 1966. BREEDING BIOLOGY AND ECOLOGY OF THE HORNED LARK IN ALPINE TUNDRA XlCOLAAS A. M. Verbeek Aspects of the breeding biology of the Horned Lark { Eremophila alpestris) are reported by Kelso l 1931 L Dubois (1935, 1936) and Bent t 1942 1 . DuBois' and Kelso’s studies dealt with prairie-nesting populations. The study here reported was conducted in alpine tundra during the summers of 1963 and 1964. Data were collected incidental to a study of the Water Pipit (Anthus spinoletta) (Verbeek, MS). In the summer of 1963 little time was spent on the larks and only four nests were located. In 1964. larks were much more abundant and 12 nests were located, 11 of which were on the study area proper and one outside. STUDY AREA The study area < Fig. 1) consisted of about 116 hectares of alpine meadow about one km XE of Beartooth Pass on the Beartooth Plateau, Park County. Wyoming. A detailed description of the vegetation and geologv' of the Plateau is given by Johnson and Billings 1 1%2 ) . The average altitude was about 3.200 m. The Beartooth Highway houndTd the study area on the south and the edge of the plateau above Rock Creek Canyon formed the western boundary. On the east. Pipit Hill, so named by us, formed part' of the study area up to about 3.262 m. The face of Pipit Hill was a dry meadow, although in places, below pockets of snow, there were isolated areas of moist meadow. ‘Scattered along the face of the hill were rock outcrops, rock polygons and solifluction terraces. On the north, the boundary ran about 100 m north of the main channel which drained the whole area. This main channel had a maze of narrow branches, manv of which were drv toward the end of the season. Frost hummocks were char- acteristic of this wet area. The vegetation consisted of plants such as Salix planifolw, Sediim rhodanthunu and Caltha leptosepala. Besides the low wet area in the north and Pipit Hill, there was the Central Ridge running through the center of the area and West Hill’ in the southwest. The Central Ridge and West Hill both had areas with fellfield characteristics such as cushion plants and much exposed rock and gravel on the western exposure. Extensive snow accumulation areas between Pipit Hill and the Central Ridge and between the latter and West Hill were bare except for some sparse vegetation in late summer when the snow had melted from part of these areas. TERRITORY AND HABITAT The larks occupied the whole study area and their nests were located m all cover types except exposed snow accumulation, frost hummocks and T\et meadow. The distribution of the nests is shown in Figure 1. For each of 11 nests in 1964, I noted the plants growing within a 30 cm radius of the nests (Table 1 1 . The nests are placed in one of four categories: ( a I Fellfield nests, characterized by cushion plants and exposed rock, (b) Di} Xleadois nests, characterized by a general absence of cushion plants; (c) Moist 208 Nicolaas A. \I. Verbeek HORNED LARK BREEDING BIOLOGY 209 r I DRY MEADOW MOIST MEADOW SNOW GZH] WET MEADOW RW1 FELLFIELD ^^ACCUMULATION Fig, 1. Distribution of nests of the Horned Lark found in 1%3 (dots) and in 1%4 Lipen circles). The sifuares are suspeiUed locations of nests in 1964. (iontour lines are 12.2 m apart. 210 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Meadow nests, characterized by moisture loving plants such as Carex scopulorum; and (d) an intermediate type between Dry and Moist Meadow. Of all the nests, including those of 1963, nine were located in a dry habitat, five in a moist habitat and one in an intermediate type. The presence of five nests in a moist habitat is unusual since heretofore lark nests have been associated only with dry and gravelly sites. Two nest territories and the areas occupied by 22 pairs reported by Drury ( 1961 ) were all located in the most exposed places “where most of the surface was tan angular rock.” Pickwell (1931) writes: “The Prairie Horned Lark selects the bleakest barrens available” and he feels that bare ground is the most essential con- dition required. The fact that nests were found in moist habitat in both years eliminates the possibility of increased population pressure in 1964 forcing the birds to occupy less favorable habitat. It seems that in an alpine population of this species, a wider range of habitat is utilized. Horned Larks have very large territories. Besides the 11 nests found in 1964 there were at least four more known territories the nests of which were not located. Because large areas on the study plot were not suitable lark habitat, it is not possible to calculate the average size of each territory by simple division. The average distance between two nests in the same con- tinuous habitat type, for instance between N16 (Nest 16) and N8, and between N8 and N7, etc., was about 142 m. If we take the nest as the center of the territory, then each territory occupied about 1.5 hectares. Larks defend their territory with great persistence throughout the breeding cycle from the moment the territory is established till the time the young leave the nest. Males chase each other with great speed, often close to the ground. Sometimes several birds participate in these chases. On 5 July 1964, two males fought by standing close together and beating one another by suddenly extending one wing. After each blow they would walk away from each other for about 30 cm and then walk back again to repeat the performance. Two males can often be seen to start a fight on the ground and then continue it in the air, climbing higher and higher up to about 20 m at times. This behavior was noted also by DuBois (1935). SONG In the alpine zone larks are the first birds to sing in the morning and the last to cease in the evening. The flight song is given from the ground as well as from the air. On the ground, males sing while perched on some pro- jection, usually a rock. In the air, the bird sings while his wings and tail are spread wide open and in between bursts of song he hovers to maintain altitude. The duration of the only flight song timed was 11 minutes, twice as long as that given by Pickwell for E. a. praticola and my impression is Nieolaas A. M. V'erbeek HORNED LARK BREEDING BIOLOGY 211 Table 1 Species of Plants Recorded Within 30 cm Radius of 11 Nests of the Horned Lark Species 5 Fellfield nests 6 9 11 Dry 7 meadow nests 8 10 Moist meadow nests 13 14 15 Intermediate meadow nest 16 Rock 1 1 1 1 Geum rossii 1 1 1 1 1 1 1 1 1 Smelowskia calycina 1 1 1 1 1 Potentilla diver sifolia 1 1 1 1 1 1 Antennaria sp. 1 Mertensia alpina 1 1 1 1 1 Silene acaulis 1 1 1 Polygonum bistortoides 1 1 1 1 1 1 1 Douglasia montana 1 Eritrichium alpinum 1 Castilleja sp. 1 1 1 1 Carex sp. 1 1 1 1 1 Myosotis alpestris 1 1 Pedicularis oederi 1 1 Lloydia serotina 1 1 1 Phlox caespitosa 1 1 1 1 Erigeron caespitosa 1 Stellaria crassifolia 1 Claytonia lanceolata 1 1 1 1 Senecio fuscatus 1 1 Draba sp. 1 1 Lupinus monticola 1 1 Cerastium sp. 1 Aster alpi genus 1 Carex scopulorum 1 1 Caltha leptosepala 1 1 1 Artemisia scopulorum 1 1 1 1 Gentian algida 1 1 Dodecatheon pauciflorum 1 Sedum stenopetalum 1 Trijolium parryi 1 that all of the flight songs were longer than the five minutes reported as a maximum by PickwelL NESTS Before the actual nest is built, a nest cavity is scratched out in the ground. The depth of this cavity varies with the substrate. In some cases a rock prevented any deeper excavation. The average depth of seven nest cavities was 5.0 cm (1.3 to 6.2). The nest is made of dead forbs and grasses. No 212 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 hair or feathers are used to line the inside. One nest was lined with an unidentified felt-like plant material. Drury ( 1961 ) reports the use of feathers in E. a. alpestris. All nests found were constructed so that there was some protective feature such as a projecting rock or a tuft of grass on the windward side. The nest entrance of 12 nests in 196T all faced between NNW and E; one faced NNW, three N, one NNE, four NE, two ENE, and one E. The pre- dominant winds were from the S and SW. A similar orientation with respect to the wind was reported by DuBois ( 1935 ( , who found nests facing between NE and SSE under prevailing W winds. I did not notice any evidence of a “pavement” of stones or mud as reported by DuBois ( 1935 I and Pickwell (1931). Eleven finished nests had an average width of 7.0 cm (6.5 to 7.6 1 and ten nests had an average depth of 3.8 cm (3.2 to 4.7). The average thickness of seven nests of which both the depth of the scooped-out nest cavity and the completed nest were known was 1.0 cm (0.3 to 1.7) . These measurements were taken after the young had left the nest. EGGS AND INCUBATION Eggs were laid early in the morning, some time before 0730 hours. The clutch size varied from two to four eggs ( one with two eggs, ten with three eggs and three with four eggs). Only two of the 16 nests were found before the clutch was completed. In N5, the third and last egg was laid in the morning of 29 June. All three eggs had hatched before 0530 hours on 10 July. In N8, the last of three eggs was laid in the morning of 2 July and the first egg hatched 13 July before 0930 hours. The other two eggs in this nest never hatched. The incubation period is taken to be about 11 days. DuBois (1935) gives an incubation period of 10 to 11 days and MacDonald (1916) states 11 days. Silloway ( 1903 ) states that both male and female incubate the eggs. My own observations make me believe that only the female incubates. There is only one clutch per season in contrast to the two clutches reported by DuBois (1935) at lower altitudes. In 1964, all eggs were laid between 25 June and 10 July. NESTLINGS The nestling period varied from 9 to 12 days with an average of 10.2 days. This is a very short period but it agrees well with the results obtained by DuBois 1 1935 ) . The young leave the nest when they have hardly any tail and when the primaries and secondaries are only one-third to one-half grown. The young are incapable of flight at first but walk readily. I caught Nicolaas A. M. \’erbeck HORNED LARK BREEDING BIOLOGY 213 AGE OF YOUNG IN DAYS Fig. 2. Growth curves of two, three and four young in three nests of the Horned Lark. one color-marked young five days after it had left the nest. It could only fly a few meters at the time and was soon exhausted. Nestling development is very rapid. The average gain in weight of nine young was 1.9 g per day (0.52 to 3.45). When the young reach a weight of about 20 g, they seem to have developed sufficiently to leave the nest. Growth curves for the young of three nests are shown in Figure 2. Earlier departures (Fig. 2) are due to disturbance caused by handling the young. One young of N9, which left when it weighed 17.6 g was recaptured 5 days later when it weighed 20.2 g. The average weight of 15 adult males in the University of Montana Zoological Museum, taken on the study area in June, July, and August, was 32.3 g and the average weight of 7 adult females of the same period was 30.6 g. The young then leave the nest when they are about two- thirds the adult weight. Sexual difference in weight in adult larks has been shown by Behle (1943) and Montagna (1943). The eyes open when the young are 3.6 days old (average of 10 nests I . The primaries and secondaries break the sheaths when the young are 6 days old ( average of 2 nests ) . During 128 minutes of observation from a blind when the young were one day old, the female brooded them for 78 minutes or about 61 per cent of the time. The average length of the brooding jieriod was 11 minutes (6 to 17). When the female was not brooding she was off gathering food for the \oung 214 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 and presumably for herself. If the male came to the nest while the female brooded, she would step off the nest till the male was finished feeding the young, after which she would resume brooding. When the young were four days old, no brooding occurred during one hour of observation, but the female provided shade by standing over the young in the nest. No shading or brooding occurred when the young were 8 days old. Both parents fed the young and both removed feces. W^hen approaching the nest to feed the young both male and female land at some distance, about 3 to 5 m, from the nest and then walk toward it. The female approaches without any vocalization, while the male makes a soft tjreeh call which seems to be a call used around the nest. After feeding is finished the female tends to walk away from the nest but sometimes she flies away from within about 30 cm of the nest. The male flies from the nest more often than he walks. The food of six nestlings in July consisted of 100 per cent insects, while 12 adults taken between 14 June and 1 September had stomach contents of 78 per cent insects and 22 per cent seeds. The 12 adults had an average of 0.15 (0.03 to 0.26 ) grams of grit in their stomachs and the nestlings had an aver- age of 0.10 (0.01 to 0.17 I grams of grit. Newly hatched larks are richly covered with a creamy-white natal down. The distribution of natal down of a young just hatched is shown in Table 2. Wetherbee ( 1957, 1958 1 has summarized the information regarding natal pterylosis of the Horned Lark. To his list of tracts present can be added: crural, rectrices, and upper tail coverts. My specimen did not have the ocular tract reported by Wetherbee ( 1958 ) . The young made begging sounds on my approach to the nest, at about 4.5 days. They directed their beaks to human sounds when 3 days old and before their eyes had opened. When about 5 days old, they followed the movement of my hand over the nest without the accompaniment of human sound. After about 6.5 days, the young no longer react to human sound and movement. After this time, when one approached they remained silent and immobile or tended to crouch deeper in the nest. Sutton and Parmelee (1955 ) report finding one instance of nestling larks out of the nest and they suggest that the unprotected and poorly lined nature of this particular nest could have been the cause of this. Observations from my blind, however, showed that the two 8-day old young of N13 left the nest whenever a parent came to the nest with food. They went as far as 30 to 40 cm from the nest and then crawled back again. At this age they do not leave the nest until the parent is about 100 cm from the nest. In N2, one of the four young appeared to be smaller and weaker. This bird died on 20 July when two large nestlings were outside of the nest while a third weak Nicolaas A. M. HORNED LARK BREEDING BIOLOGY \ erbeek 215 Table 2 Tract Distribution of Natal Down Feathers of a Horned Lark Nestling (Just Hatched) Tract Left Right Coronal 14 13 Occipital 12 11 Dorsal 22 22 Spinal 7 Rectrices 6 6 Upper tail covert 2 3 Humeral 12 14 Greater secondary covert 9 10 Middle secondary covert 8 6 Carpal remex covert 1 1 Femoral 15 13 Crural 2 2 Abdominal 2 2 nestling was in the nest. The latter nestling died the next day. In N14, on 12 July, three of the four young were out of the nest, the smallest one farthest away, about 30 cm. The next day this one had died, while the other three were back in the nest. It seems that nestling larks leave the nest in com- petition for food. When the young were about 4 days old, they panted when the sun shone in the nest. Panting could have started at an earlier age but was not observed. FLEDGLINGS Newly fledged young are more often heard than seen after they leave the nest. They call their parents with a single loud peep which sounds as if it comes from far away, although the young in actuality may only he a few meters away. The young are very well concealed and crouch when ap- proached. One young of N6 left the nest when it was 9 days old and I saw it fly about 75 m when it was 15 days old. Young larks fly in an un- dulating manner, more so than the adults do. When they alight they face the intruder and they have a habit of bowing their heads, as if looking at their feet. This bowing is repeated about once every four seconds. BREEDING SUCCESS There was a great difference in breeding success between 1963 and 1961. In 1963, of 13 eggs laid in 4 nests, 10 young hatched, only four of which fledged, a success of 31 per cent. In 1961. out of 31 eggs in 11 nests. 31 2J6 THE WILSON BULLETIN June 1067 Vol. 79. No. 2 Table 3 Summary of Breeding Data of THE Horned Lark 1963 Number Percent 1964 Number Percent Nests 4 11 Eggs laid 13 100.00 34 100.00 Eggs per nest 3.25 3.09 Eggs hatched 10 76.92 31 91.18 Eggs hatched per nest 2.50 2.82 Eggs not hatched 0 0.00 2 5.88 Eggs lost before hatching 3 23.08 1 2.94 Young fledged of eggs hatched 4 40.00 21 67.74 Young fledged per nest 1.00 1.82 Young lost before fledging 6 60.00 10 32.26 Young fledged of eggs laid 4 30.77 21 61.76 hatched, 21 of which fledged for a breeding success of 62 per cent. Details are shown in Table 3. Causes of mortality were twofold. In 1963, 3 eggs and 6 of the 10 young that hatched were eaten by mammalian predators, probably the deer mouse (Peromysciis maniculatus) ^ which was abundant that summer ( Pattie, MS). No nestlings were lost to mammalian predators in 1964. The loss of 8 nestlings in 1964 was due to blowfly larvae. The average age at death in infested nests was 8.6 days. In each of two nests one young survived. These young showed evidence of having suffered from the larvae. Their development was slowed down and the nestling period extended to 11 and 12 days. In one nest the larvae did not seem to have harmed the nestlings at all, although there were 29 larvae in the nest. Early fledging could be advantageous in escaping blowfly predation. Dead young are removed by the adults. POST-NESTING PERIOD Toward the middle of August when the young are independent of the adults, flocks begin to form. These flocks are very loose in nature with 10 to 20 birds scattered out in ones and twos over about 30 to 40 sq m. Whereas earlier in the season larks are found in many habitats, toward the end of the summer they are found almost exclusively in Eellfield and Dry Meadow, in this order. SUMMARY An account is given of the breeding biology of the Horned Lark in alpine meadows at an altitude of 3,200 m on the Beartooth Plateau, Park County, Wyoming. Of a total \icoIaas A. M. Verbeek HORNED LARK BREEDING BIOLOGY 217 of 15 nests, 9 were located in a dry habitat, 5 in a moist habitat and one in an inter- mediate type. Lark territories were large and in 1964 each occupied about 1.5 hectares. All nests faced between NNW and E, away from the predominant S and SW winds. Each nest had some protective feature in the form of a rock or vegetation on the wind- ward side. The average clutch size was 3.1. The incubation period was about 11 days in two nests. Only the female incubates and there is only one clutch per season. The average nestling period was 10.2 days. Young develop rapidly and gain on the average 1.9 g per day. Young leave the nest when they weigh about 20 g. The eyes open on the average when the young are 3.6 days old and the primaries and secondaries break their sheaths when the young are 6 days old. Nestling mortality in 1963 was believed due to the deer mouse, while in 1964, nestlings were lost due to predation by blow- fly larvae. Young leave the nest before they are able to fly and they become independent of the adults by the middle of August at which time flocks begin to form. ACKNOWLEDGMENTS This study was made possible by a grant from the Frank M. Chapman Memorial Fund of the American Museum of Natural Flistory and a Louis Agassiz Fuertes Research Grant of the Wilson Ornithological Society. I also wish to acknowledge funds from National Science Foundation Grant No B14098 directed by Drs. R. D. Taber and R. S. Hoffmann. Special thanks are due to Mr. D. L. Pattie and Mr. C. I. Fudge for their companion- ship in the field and the latter for some lark data for the 1963 season. Drs. R. S. Hoffmann and F. A. Pitelka read and criticized the manuscript for which I extend my sincere thanks. LITERATURE CITED Beiile, W. H. 1943 Weights of some western subspecies of Horned Larks. Auk, 60:216-221. Bent, A. C. 1942 Life histories of North American flycatchers, larks, swallows, and allies. JJ.S. Natl. Mils. Bull., 179. Drury, W. H. 1961 Studies of the breeding biology of Horned Lark, Water Pipit, Lapland Long- spur, and Snow Bunting on Bylot Island, Northwest Territories, Canada. Bird-Banding, 32:1-46. DuBois, A. D. 1935 Nests of Horned Larks and longspurs on a Montana Prairie. Condor, 37: 56-72. 1936 Habits and nest life of the Desert Horned Lark. Condor, 38:49-56. .Johnson, P. L., and W. D. Billings 1962 The alpine vegetation of the Beartooth Plateau in relation to cryopedogenic processes and patterns. Ecol. Monog., 32:105-135. Kelso, L. H. 1931 Some notes on young Desert Horned Larks. Condor 33:60-65. MacDonald, H. 1916 Incubation period of the Horned Lark. Auk, 33:435. Montagna, W. 1943 Weights and plumages of tbe Horned Larks of Central New ^ ork. Auk, 60:210 2L5. 218 THE WILSON BULLETIN June 1967 Vol. 79. No. 2 PiCKWELL. G. B. 1931 The Prairie Horned Lark Trans. Acad. Sci. St. Louis. 27:1-160. SiLLOWAY. P. M. 1903 Birds of Fergus County. Montana. Press of the Argus. Lewiston. Montana. Fergus Co. Free High School Bull.. 1:1-77. Si TTON. G. M.. AND D. F. Parmelee 1955 Nesting of the Horned Lark on Baffin Island. Bird-Banding. 26:1-18. ■^'etherbee. D. K. 1957 Natal plumages and downy pterylosis of passerine birds of North America. Am. Mus. \at. Hist. Bull.. 113:343-436. 1958 New descriptions of natal pteiNlosis of various bird species. Bird-Banding. 29:232-236. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MONTANA, MISSOULA, MONTANA I PRESENT ADDRESS: MUSEUM OF VERTEBRATE ZOOLOGY, UNIVERSITY OF CALI- FORNIA, BERKELEY, CALIFORNIA I 19 MARCH 1966 NEW LIFE MEMBER Dr. Glen E. oolfenden has recently be- come a Life Member of The \^'ilson Orni- thological Society. Dr. "^’oolfenden is As- sociate Professor of Zoology at The Lniversity of South Florida. Tampa, and holds degrees from Cornell Lniversity. Lniversity of Kansas, and Lniversity of Florida. His ornithological interests include anatomy, ecology, systeniatics. and paleon- tology. and he has published 25 papers in these fields. He is a member of the Cooper Society. Bird Banding Association. BOL. Sigma Xi. Florida Academy of Sciences, and an Elective member of the AOL . Dr. oolfenden is married and has three chil- dren. OBSERVATIONS ON A LOCALIZED DUCK SICKNESS IN THE DELTA MARSH; SUMMER, 1964 David A. Manuwal The 33,000-acre Delta Marsh, in south-central Manitoba, lies at the southern end of Lake Manitoba and is an important part of the water- fowl breeding area of Manitoba. Between the lake and the marsh, some nineteen miles of narrow, sandy, wooded ridge offers protection from strong winds and wave action from the lake. The marsh is a series of shallow bays and sloughs connected by small waterways with only two outlets to the lake- a channel at Delta in the west and Clandeboye Dam in the east. The water level of the marsh is greatly affected by strong winds. Covering most of the marsh is a vast stand of phragmites iPhra^mites communis] . This plant is rarely found in water exceeding one-half meter in depth during the summer. Close to the phragmites, and often growing on islands are bulrushes (Scirpus) and, occasionally, cattails iTypha). In the deeper waters, sago pondweed, water milfoil, co- ontail, and other aquatic plants form beds that sometimes make it difficult to canoe. In past years, serious outbreaks of duck sickness at Delta were, in most cases, attributed to avian botulism. H. Albert Hochbaum, Director of the Delta Waterfowl Research Station, notes that no major outbreaks occurred there before 1957. However, in 1957 there was a serious outbreak in which losses in the Lake Manitoba basin numbered about 500,000 ducks. Dying birds were found everywhere there was exposed shoreline that was reflooded by wind and rain. Since then, only small outbreaks have occurred. On 3 August, 1964, an outbreak was reported at 22 Bay, a small body of water above five miles east of Delta. It was evident from the decomposed bird carcasses that the initial outbreak had occurred on about 20 July. The lack of laboratory facilities made it impossible to determine that Clostridium hotulinum (Type C) was indeed the lethal agent in the 1964 outbreak. 22 Bay is located about one-half mile south of Lake Manitoba, and is approximately five-eighths of a mile across at its widest point. The vegeta- tion is typical of the Delta Marsh, having a phragmites border, bulrush islands, and floating aquatics in open water. The bay is fed by one ditch and has outlets to a larger body of water ( Blackfox Lake) to the south and a small bay to the east. The entire perimeter at the time of the study was surrounded by exposed mudflats of varying size. The bay was divided into five study units ( 1-V. Jable 2). each of which was composed of approximately 150 to 175 yards of ex})osed mudflats, shore- line, and islands. The units were checked in regular setpience as often as 219 220 THE WILSOX BULLETIN June 1967 Vol. 79, No. 2 Sex. Age, and Condition Table 1 OF Ducks Found AT 22 Bay, 1964 Species Ad.cf Ad. 9 Juv.cf Juv. 9 Downy* Und.** Flight less Sick Total Pintail 89 33 15 11 2A, 2A 15 32 18 165 Blue-winged Teal 89 38 10 20 10 7 13 167 Mallard 67 12 6 2 15 9 14 102 Gadwall 28 3 1 lA, lA, 2A 3 19 3 38 Green-winged Teal 25 16 1 2 5 5 44 Shoveler 4 1 1 3 2 2 1 11 Am. Widgeon 18 4 14 22 Redhead 8 1 lA, lA 1 4 1 12 Canvasback 1 1 lA, lA 1 2 5 Black Duck 3 1 3 4 Ruddy Duck 2 2 Ring-necked Duck 1 2 Lesser Scaup 1 1 L^nidentified 92 Totals 337 105 37 38 9 54 94 58 666 * Refers to brood class. ( Gollop & Marshall, 1954. lA, downy young, no feathers visible; 2A, partly feathered as view from side. ) ** Unidentified as to sex and age. possible, usually every day. Dead and sick birds were sexed. aged, and taken back to the station for dissection and examination. The upper digestive tract was immediately removed and preserved in 10 per cent formalin so that ani- mal matter present would not be further digested. The report of this analysis is not yet available. The mechanism involved in the production and release of the bacterium Clostridium hotulinum (Tvpe C) appears to be closely associated with fluc- tuating water levels and the presence of large numbers of marsh flies ( Chironomidae I . Both of these conditions prevailed at 22 Bay. Strong winds caused water level fluctuations up to eight feet throughout most of August. The weather during August was quite variable. Most of the month was rather cool. Early morning temperatures were usually in the high 40’s, and day readings ranged in the 60’s and 70’s. The bay was checked from 4 to 25 August; on 12 of these days sick or dead birds were found. Occasionally, it was impossible to check every day, so some of the dead birds reported on certain dates may have been alive the day before. Tables 1 and 2 show the findings. Botulism deaths result from two main causes: (1) a massive dose of toxin ingested while eating insect larval cases and ( 2 ) the ingestion of re- peated sublethal doses of toxin plus food in water containing large amounts of dissolved salts (Gooch, 1964). Clostridium botulinum (Type C) blocks the parasympathetic nervous system and thereby affects gland function. Ob- David A. Manuwal DUCK SICKNESS IN THE DELTA MARSH 221 Table 2 Birds Other Than Ducks Found at 22 Bay AND Blackfox Lake, 1964 Species Total number Sick Study units Blackfox L. I II III IV V Lesser Yellowlegs 54 10 18 3 6 5 5 17 Greater Yellowlegs 1 0 1 American Avocet 1 0 1 Dowitcher 8 4 2 1 1 2 2 Killdeer 1 1 1 Semipalmated Plover 3 3 1 1 1 Pectoral Sandpiper 43 6 2 5 4 17 1 14 Least Sandpiper 15 8 3 1 1 3 7 Semipal. Sandpiper 24 16 10 1 2 2 4 5 Stilt Sandpiper 8 6 1 3 1 1 2 Spotted Sandpiper 3 2 2 1 Wilson’s Phalarope 1 0 1 Ring-billed Gull 14 8 3 5 5 1 Franklin’s Gull 6 0 1 2 3 Bonaparte’s Gull 4 0 4 Black Tern 7 1 1 1 5 Forster’s Tern 1 0 1 Bl-crowned Night Heron 1 0 1 Am. Coot 18 2 4 5 1 1 8 Pied-billed Grebe 2 0 1 1 Eared Grebe 2 0 1 1 Red-necked Grebe 1 0 1 Marsh Hawk 1 1 1 Totals 219 58 52 21 25 37 20 65 served symptoms of sick birds at 22 Bay were the following: loss of ability to fly; paralysis in legs; diarrhea; non-functioning nictitating membrane; and complete collapse. During the time of the outbreak, waterfowl usage of 22 Bay was quite intensive. Pintails (Anas acuta). Blue-winged Teal [Anas discors). Mallards (Anas platyrhynchos ) , American Widgeons iMareca americana). Gadwalls (Anas strepera), and American Coots \Fulica americana) made up the bulk of the waterfowl. Lesser Yellowlegs {Totanus flavipes), Dowitchers \ Limno- dromus sp. ), Semipalmated Sandpipers [Ereunetes pusilliis), and Pectoral Sandpipers ( Erolia melanotis I were the most common shorehirds. The peak population on 22 Bay occurred around the first week in August when about 1 ()()() to 1500 birds were present. A few duck broods were still utilizing the open water during the first 10 to I f days of August. Most of these were Redheads ( Aythya americana). An increase in the numher of shorehirds (more specifically, the “peeps”), gulls, and terns was noted. By the third week of August, about 1 100 White Pelicans I Eelecanus erythrorhynchus I were 222 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 using the bay and Blackfox Lake as well as other parts of the marsh. Also at this time, the number of ducks, especially Pintails, decreased. There was a slight increase in Shovelers {Spatula clypeata) toward the end of the third week. Herons, rails, and Marsh Hawks ( Circus cyaneus ) also used the area. Evidence of muskrats, skunks, and raccoons was found along the mudflats. Skunks and raccoons appeared to have eaten many of the dead birds and it is likely that several sick birds were taken. On several occasions. Marsh Hawks were observed eating both dead and freshly killed birds. The numbers of birds affected by the sickness were directly proportional to the numbers utilizing the area. The sickness was non-selective as to sex and age. With the exception of rails, all the species in 22 Bay were af- fected by the sickness. However, it is quite likely that some rails were killed. Blue-winged Teals and Pintails were the birds most commonly seen feeding along the edge of the bay and; as the data show, these two species accounted for more than half the dead ducks (332 of 574). The Mallard was the third most common species at the bay edges and also ranked third among the birds affected by the sickness. SUMMARY An isolated outbreak of duck sickness was studied in the Delta Marsh, Manitoba. Evidence suggests that the bacterium Clostridium hotulinum (Type C) was responsible for the deaths of 885 birds found at 22 Bay. The deaths were closely associated with fluctuating water levels. The ducks found most numerous in the kill were the Pintail, Blue-winged Teal, Mallard. Among the ducks represented, a large proportion (76:24) were drakes; however, for juvenile birds, a nearly perfect 50 : 50 ratio existed. Other species, including shorebirds, gulls, terns, herons, grebes. Coots, and Marsh Hawks were found sick. ACKNOWLEDGMENTS I wish to thank the staff of the Delta Waterfowl Research Station for their assistance and especially Dr. H. A. Hochbaum for his advice. I am also indebted to Drs. D. L. Allen, C, M. Kirkpatrick, and R. E. Mumford, Department of Forestry and Conserva- tion, Purdue University for reviewing the manuscript. LITERATURE CITED CoocH, F. G. 1964 A preliminary study of the survival value of a functional salt gland in prairie Anatidae. 4 w/c, 81 : 380-393. Gollup, J. B., and W. H, Marshall 1954 A guide to aging duck broods in the field. Mississippi Flyway Council Tech. Sect. Rept. ( Mimeo ) . Hochbaum, H. A, 1944 The Canvasback on a prairie marsh. Stackpole Co., Harrisburg, Pa. DELTA WATERFOWL RESEARCH STATION, DELTA, MANITOBA (PRESENT ADDRESS: DEPARTMENT OF FORESTRY, UNIVERSITY OF MONTANA, MISSOULA, MONTANA) ORIGINALLY RECEIVED 15 DECEMBER 1965. MIGRATION IN THE LITTLE BLUE HERON Julian L. Dusi Migration in the Little Blue Heron {Florida caerulea) is a composite of three distinct phases: 1) dispersal of the young and adults from the colonial nesting sites; 2) the autumnal southward movement of adults and of the young after their dispersal; and 3) the return to the breeding areas in the north the following spring. The writer started banding Little Blue Herons in 1953, at a colony south of Tuskegee, Alabama, in an attempt to obtain the data necessary to describe these migrations. Since then he has been banding them at a number of colonies distributed over the state. Data other than the bandings done by the writer were needed to explain North American migration outside of Alabama. Reports in the literature, especially those of Ben B. Coffey, Jr. (1943, 1948), have been very helpful. A listing of bandings and recoveries for the years 1926 to 1962, provided by Allen J. Duvall, from the Fish and Wildlife Service Bird Banding Laboratory, have been an additional important source of information. PROCEDURES Practically all of the banding of Little Blue Herons has taken place at their colonial nesting sites and practically all of the birds banded have been nestlings. Adults have been difficult to capture, whereas the nestlings have been much more easily obtained in sufficient numbers to make banding them attractive. The banding of the nestlings has presented several problems mostly eoncerned with the inaccessibility of the breeding colonies and nests. The majority of the colonies has been located in small brushy ponds or swamps. The others have been in upland situations, usually with ponds, swamps, or rivers nearby. In the colonies located over water and in low bushes, the nests have l)een easy to reach and the young easily cap- tured by hand or by the use of bamboo poles with wire hooks on the ends. In the colonies with higher trees, nests were frequently 20-25 feet above the water. Longer poles with hooks and baskets, or light weight extension ladders were needed in these colonies. Our use of an extension ladder from a small boat has worked well in one swamp. In upland colonies, trees were much taller and nests were frequently 35-50 feet high. This made the use of poles with hooks, from the ground, must less satis- factory or impossible. If the young fall into water, little damage is done, hut if they fall onto the land, before they can use their wings to break their fall, they are usually fatally injured. Therefore, in upland colonies, the use of extension ladders was necessary when the nests were more than 15 feet from the ground. In our work, the use of a 36-foot magnesium ladder has been very successful. The trees were usually tall and spindly and would not support much weight. If the ladder was placed tightly against the tree and tied to the tree every 10 feet, as it was ascended, it supported the tree 22.3 224 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Table Dispersal of 1 Young Banding Locality Banding Date Recovery Locality Recovery Date Tuskegee, Ala. 6-12-53 Rising Fawn, Ga. 8-_-53 M H 5-27-55 Harperville, Miss. 7- 7-55 M M 1 1 Etowah, Tenn. 7- 2-55 M ft M Meridian, Miss. 8-12-55 It M 5-14-56 Eastman, Ga. 6-19-56 M M n Columbus, Ga. 8-25-56 Marvyn, Ala. 5-22-59 Thomaston, Ga. 7-_-59 Mt. Creek, Ala. 6-14-60 Oneonta, Ala. 8- 1-60 Opp, Ala. 5-22-61 Andalusia, Ala. 7-10-61 M If It II II 7- 3-61 II II 5-30-62 .. .. 9-18-62 Pansey, Ala. 5-13-64 Willacoochee, Ga. 8-_-64 Florala, Ala. 6- 1-64 Thomasville, Ga. -_-64 St. Marks, Fla. 6- 6-26 Jacksonville, Fla. 9-_-26 II II 6- 3-61 Ashburn, Ga. 8-21-61 Glen Allan, Miss. 5-25-36 Dalton, Ga. 8-28-36 II II II Jena, La. 7- 6-36 11 II 5-24-36 Baton Rouge, La. 7-_-36 II II Corning, Ark. 7-_-36 II II Helena, Ark. 7- 6-36 II II 1 1 Watson, Ark. 7- 4-36 II II 1 1 Star City, Ark. ll-_-36 II It M Delaplaine, Ark. 7-_-36 II II 1 1 Wellston, Ohio 8-_-36 Harperville, Miss. 1 1 Desha Co., Ark. 7-_-36 II II 5-31-36 Jennie, Ark. 7-12-36 II II n Merigold, Miss. 7- 3-36 II II 1 1 Louisville, Miss. 7-27-36 II II 1 1 Denmark, Miss. 7- 3-36 II II Drew, Miss. 7- 6-36 It If 1 1 Isola, Miss. 8-20-36 Glen Allan, Aliss. 6- 7-36 Mayersville, Miss. 7-_-36 II II 1 1 Booneville, Miss. 8-_-36 II II 1 1 Tallula, Miss. 7-_-36 II II 1 1 Indianola, Miss. 8-_-36 II II 5-23-37 Rosedale, Miss. 8-_-37 II II M Holland, Mo. 7-22-37 II II 1 1 Vicksburg, Miss. 8- 3-37 II II 1 1 New Albany, Miss. 8-_-37 II II 1 1 Pollard, Ark. 8-_-37 II 11 1 1 Doniphan, Mo. 7-_-37 II n 1 1 Indian Bay, Ark. 7-12-37 M II 1 1 Marked Tree, Ark. 7- 8-37 11 II " Leland, Miss. 7-_-37 Julian L. Dusi LITTLE BLUE HERON MIGRATION 225 Table 1 [cont.) Banding Banding Recovery Recovery Locality Date Locality Date M II n Alligator, Miss. 7-_-37 M M M Acworth, Ga. 8-_-37 M II M Crockett’s Bluff, Ark. 7-_-37 II II 6- 6-37 Batesville, Miss. 8-_-37 II II II Burr Ferry, La. 9- 7-37 II II II Crockett’s Bluff, Ark. 9-_-37 II II „ Ruleville, Miss. 7-_-37 M II 1 1 Sikeston, Mo. _-_-37 II II 1 1 Harrisburg, Ark. 7-20-37 II II 1 1 Lake Village, Ark. 7-_-37 II II M Carroll Parish, La. 9-_-37 II II ,, Drew, Miss. 7-_-37 Moon Lake, Miss. 6- 3-40 Elaine, Ark. 7-21-40 II II 1 1 Gunnison, Miss. 7-_-40 II II 1 1 Crowville, La. 8- 9-40 II II M Abbeville, La. 8-_-40 II II 6- 1-41 Lucy, Tenn, 6-30-41 II II n Hogansville, Ga. 7-25-41 II II 1 1 Calhoun, Ala. 9-10-41 II II 6- 7-42 Uniontown, Ky. 9-19-42 Glen Allan, Miss. 5-25-47 New Iberia, La. 8-_-47 M M II Marked Tree, Ark. 7-_-47 Moon Lake, Miss. 6- 1-47 Kennett, Mo. 8-23-47 Glen Allan, Miss. 6-15-47 Marked Tree, Ark. 7-18-47 II II 1 1 Beaumont, Texas 10-_-47 II II 11 Moon Lake, Miss. 9-_-47 II II 6-13-48 Bastrop, La. 9-25-48 II II II Memphis, Tenn. 8-14-48 Norwood, Pa. 6- 2-41 Williamstown, N.J. 6- 7-41 Elizabethtown, N.C. 6- 1-43 Goldsboro, N.C. 7- 8-43 II II n Dillion, N.C. 7-15-43 II II 6- 3-43 Sanford, N.C. 8-_-43 II II II Salisbury, N.C. 7-_-43 II M M Spartansburg, S.C. 7-26-43 II 11 5-28-53 Danville, Va. 7- 4-53 Muskogee, Okla. 5-25-58 Warsaw, Mo. 9-_-58 II II 5-31-58 Vinita, Okla. 8-16-58 Arkoma, Okla. 5-23-59 Forest City, Ark. 7-_-59 Okla. City, Okla. 6- 7-59 Lebanon, Mo. 8-18-59 Webber Falls, Okla. 6-13-59 Waco, Texas 9-_-59 II II II Claremore, Okla. 8-_-59 Arkoma, Okla. ,, Heavener, Okla. 8-21-59 Webber Falls, Okla. 6-14-59 Waco, Texas 9- _ -59 Muskogee, Okla. 6-12-60 Grove, Okla. 8-_-60 Charleston, S.C. 6- 9-31 Orktown, Va. 8-20-31 226 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 Table 1 icont.) Banding Banding Recovery Recovery' Locality Date Locality Date If n 8- 9-35 Moncks Corner, S.C. 10-14-35 Memphis, Tenn. 6- 7-42 Covington, Tenn. 7-12-42 II M M Monette, Ark. 7- 6-42 Dyersburg, Tenn. 6- 2-51 Madisonville, Ky. 7-22-51 Anahuac, Texas 5- 2-26 Fort Worth, Texas 9-11-26 II II 5-25-26 Baytown, Texas 7-17-26 It It 6- 3-26 Shelbyville, Ind. 8- 7-26 tl It 7-29-27 Alvin, Texas 9-19-27 It It 6- 3-30 Nacogdoches, Texas 7-_-30 M It 1 1 Tyler, Texas 7-15-30 Columbus, Texas 6- 4-38 Jennings, La. 7-29-38 Note: Banding and recovery localities are approximations determined from coordinates, except for Alabama banding localities which are the writer’s. from bending and was much more safe. If the climber tied himself to the tree, at the top of his ascent, then caught the birds with his hands or a short pole with a wire hook, and then lowered them in a plastic bucket to a helper on the ground who did the banding and recorded the data, he could work much more efficiently. The construction of the poles with hooks and baskets was simple. James E. Keeler, Alabama Department of Conservation, introduced the writer to the use of the hooks in a cooperative effort in banding White Ibises (Keeler, 1956). A bamboo pole of suitable length was obtained. A piece of eight or nine gauge iron wire, about four feet long, was attached to the upper two feet of the pole using several wrappings of adhesive tape. The end of the wire was then bent so that about six or eight inches of the wire was parallel to the rest of the wire and about one inch from it. The very end was bent out slightly so that it was easier to guide the hook around the neck of a bird. The basket was made with a similar pole and piece of wire. The wire was bent to form a loop six to eight inches wide and about 18 inches long. A piece of one-inch mesh chicken wire about 8 inches by 16 inches was slipped over the frame and the ends of the frame were attached to the pole with adhesive tape. Keeler found that if the Table 2 Dispersal of Adults Banding Locality Banding Date Recovery Locality Recovery Date Tuskegee, Ala. 5-14-56 Wadesboro, N.C. 10-15-60 Glen Allan, Miss. 5-23-37 Oakland Mills, Iowa 10-27-41 It M 6- 6-37 New Orleans, La. 7-19-39 Moon Lake, Miss. 6- 3-40 It M 8- 5-40 It 1 1 6- 7-42 It It 8-_-44 Muskogee, Okla. 6- 6-59 Dyersburg, Tenn. CO Bay Town, Texas 5- 2-26 Baton Rouge, La. 7-31-27 Julian L. I) usi LITTLE BLUE HERON MIGRATION 227 Table 3 Southward Migration Banding Banding Recovery Recovery Locality Date Locality Date Tuskegee, Ala. 5-27-55 British Guiana 3- 1-61 M II It Puerto Rico 10-31-55 II II 11 Venezuela 12-16-55 II II 1 1 British W. Indies 10-23-55 11 II II Honduras 1-29-56 II II 1 1 Cuba 1-15-60 II II II 1 1 2-13-58 II II 1 1 Bahamas 3-_-56 II II 5-14-56 British Guiana 2- 3-60 II II 6-16-57 Venezuela 10-_-63 Marvyn, Ala. 6- 6-58 British W. Indies 10-15-61 II M ,, British Guiana 6- 9-59 II II 5-22-59 British W. Indies 9-27-59 II 11 II British Guiana 2-15-60 Faunsclale, Ala. 6- 1-59 Cuba 8-_-60 Opp, Ala. 6-22-60 Venezuela 10-12-60 n .. 6-12-61 Cuba 9-24-61 II II 5-10-62 Lake City, Fla. 6-17-64 Delaware 9-14-51 Haiti l-_-52 St. Marks, Fla. 5-22-39 Panama 11- 1-39 M II 6-24-61 Jamaica l-_-62 New Iberia, La. 7-17-37 Mexico 10- 2-37 Harpersville, Miss. 6-16-35 If 10-_-37 II II 6-16-35 British Honduras 7-20-36 Glen Allan, Miss. 5-25-36 Cuba 10-13-38 M It 1 1 Colombia _-_-43 M M 5-24-36 Mexico 9-28-36 II II ,, French W. Indies 9-_-36 Harpersville, Miss. 5-31-36 Mexico 1-23-38 Glen Allan, Miss. 5-23-37 Colombia 4-19-50 II II M Cuba 7-16-41 II II M Honduras 9-_-37 11 II II Mexico 9-30-37 II II 6- 6-37 Honduras 10- 8-37 II II 1 1 Panama 10-17-37 Moon Lake, Aliss. 6- 3-40 British Honduras 12- 6-40 II It M Mexico 12-13-40 II 11 6- 1-41 ,, 2-_-54 II II 6-7-42 M 4- 2-46 Glen Allan, Miss. 5-25-47 Nicaragua 11-20-49 II II II Haiti 3-15-48 Moon Lake, Miss. 6- 1-47 Mexico 10- 4-47 M M M Cuba 2-22-48 Glen Allan, Miss. 6-15-47 Panama 3-10-51 228 THE WILSON BULLETIN June 1967 Vol. 79, x\o. 2 Table 3. [cont.) Banding Locality Banding Date Recovery Locality Recovery- Date 1? tl ,, Puerto Rico 4- 1-49 M M ,1 Mexico 2-_-49 Wildwood, N.J. 6- 8-41 British W. Indies 11- 6-41 fl It 5-29-49 II II II 12- 3-49 Clarkton, N.C. 6- 1-43 II II II l-_-44 II II 5-25-54 Cuba 5- 6-55 II II 6-15-54 Bahamas 12- 7-54 Muskogee, Okla. 5-25-58 Mexico ll-_-58 II II 1 1 II ll-_-58 II II 5-23-59 Colombia 1-16-60 II II 5-24-59 Costa Rica 8-22-60 Greenwood, Okla. 5-23-59 Mexico 3-10-60 Okla. City, Okla. 6- 7-59 British Honduras 3- 7-60 II II ,1 Nicaragua 12-_-59 Okmulgee, Okla. 6-13-59 Mexico 10-13-60 M M II Costa Rica 11-26-59 M II Panama 11-26-59 Arkoma, Okla. M Nicaragua 3-_-60 Muskogee, Okla. II Costa Rica 5-_-60 II II 6-14-59 Mexico 9-15-59 11 II II II 2- 2-60 II II 1 1 1 1 8-15-60 Arkoma, Okla. 6- 4-60 1, 12-_-60 II II II Panama 9-24-60 II II 1 1 Costa Rica 9-30-60 11 II 6-18-60 Colombia o r bs o Muskogee, Okla. 6-12-60 Panama 10-_-60 Charleston, S.C. 6-15-31 Louisiana 6-19-36 M II 6-11-32 Jamaica 10-30-34 II 6-24-32 British Honduras 9-25-32 II II 1. Cuba 11-18-38 II II 6-12-33 Bahamas 10- 1-35 M II II Colombia 4-_-38 II II 1. British W. Indies 1-16-34 II 6- 6-34 Venezuela 10-21-34 5-29-37 Haiti 2-_-43 II II 6- 5-38 Cuba 10-26-38 Dyersburg, Tenn. 6- 5-51 Colombia 3-21-53 II II 1 1 Mexico 12-_-51 Galveston, Texas 5-12-26 II 10- 1-26 II II 6-25-26 British Honduras 11-20-26 II II 6-14-26 Mexico 10-18-26 II II 6- 3-30 M 8-28-30 Note: Banding and recovery localities are approximations determined from coordinates, except for the Alabama banding localities. Julian L. Du si LITTLE BLUE HERON MIGRATION 229 Table 4 Northward Migration Banding Locality Banding Date Recovery Locality Recovery Date Tuskegee, Ala 5-11-55 Wetumpka, Ala. 5-16-60 II M M Opp, Ala. 3-_-59 n M 5-20-55 Summit, Miss. 3-24-57 n M 5-27-55 Selma, Ala. 6-30-57 n M 5-14-56 Tuskegee, Ala. 8- 2-59=^ Opp, Ala. 5-30-62 Dothan, Ala. 4-20-63 Glen Allan, Miss. 5-25-36 Coushatta, La. 3-28-38 II II 5-24-36 Winnsboro, La. 5- 2-40 II M II Indianola, Miss. 4- 8-38 Harperville, Aliss. 5-31-36 Oxford, Miss. 7-26-38 II M 1 1 Natchez, Miss. 6- 1-40 Glen Allan, Miss. 5-23-37 Gonzales, Texas 3-26-39 II II 1 1 Indianola, Miss. 2-_-38 M It 6- 6-37 Bernie, Mo. 3-_-44 Moon Lake, Miss. 6- 3-40 Prichard, Miss. 2-_-46 .. .. 1 1 Batesville, Miss. 3-_-43 If It M Eudora, Miss. 3-14-41 II II I 1 Swan Lake, Miss. 6-_-43 II II 6- 1-41 Clarksdale, Miss. 4-_-42 II II 6- 7-42 Crockett’s Bluff, Ark. 4- 8-47 Glen Allan, Miss. 6- 1-47 Memphis, Tenn. l-_-54 Clarkton, N.C. 5-30-42 Boardman, N.C. 4-_-44 II II 6- 3-43 Clarkton, N.C. 4-26-50 Charleston, S.C. 5-29-37 Morehead City, N.C. 2-_-38 * A date this late does not necessarily indicate the destination of spring migration but may reflect post-breeding dispersal before autumnal migration. Note: Banding and recovery localities are approximations determined from coordinates, except for Alabama banding localities. birds were caught by the neck, they would release their toe-holds; if caught by the leg, they usually held on and the leg would be broken. Little Blue Herons are quite agile climbers and can frequently be returned to the nest by perching them on the pole, below the hook, and raising them to their nests. Little Blue Heron nestlings that cannot climb well and some of the other herons and ibises, are best returned to the nests in the baskets. The size of the nestlings banded varied greatly. The optimum size was that attained at about two weeks of age, at which time the birds were able to climb a little but not enough to evade the bander easily. At one week of age, the birds are at tbe minimum size at which the proper size band will stay on the tarsus. At about four weeks of age, the young are able to climb so well that it is difficult to capture them. It was our practice to start banding when the first group was about two weeks old and to return at periods of 230 THE WILSON BULLETIN June 1967 79, No. 2 Fig. 1. Dispersal of Youn{>; From N(\stin«r (Colonies. Faeli numher represents a colony (circled) and the hand recoveries from that y noting on the map the name of the bird to which it belongs, hut not always. On page 152, for instance, the map opposite the Least Auklet obviously belongs to the Marbled Murrelet, the bird below. This is something that should certainly be corrected in future editions of the hook. Another unique feature of the hook is the use of sonagrams for depicting songs and calls. To my mind this is the least successful feature. While sonagrams have value in scientific studies of bird calls, their usefulness as an aid to field identification is very limited. To begin with, considerable practice is needed in order to he able to read sonagrams; but even when some proficiency is acquired, I doubt if anyone can really imagine or “hear” a new song simply by reading its sonagram. I challenge anyone who has never heard the call of a Red-hellied or a Gila woodpecker to “hear” the difference between their calls by reading the sonagrams on page 182. Admittedly it is interesting to see what a call which you already know looks like as a sonagram, hut this is not the point. A field guide should teach you to have an idea of a song before you hear it. I maintain that you cannot learn bird songs from sonagrams. Bird songs are best learned from records, of which there is a wide variety now available covering just about every North American species. In a hook, they are best depicted by the time-honored method of verbal description, and the authors have been wise to include many such descriptions in the text. There is no sonagram for Coues’ Flycatcher; there is no need for one. The authors’ description of its call as “a sad, whistled ‘ho-say mari-a’ ” is more effective. We all know that the Olive-sided Flycatcher says “Q)uick, three beers,” (all, that is, exeept the authors, who maintain it says “whip, three beers,” thereby turning a memorable phrase into a more accurate hut meaningless one). There is no need to add a sonagram of its song, as has been done; the verbal description is perfect. There are a number of smaller points on which there is room for improvement in the book. In a number of places the color is not true, and this may in part have occurred in the printing. The Baird’s Sandpiper on page 128, for instance, shows a lot of yellow in 254 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 the plumage, and looks quite different from the same bird pictured on page 125. In a number of illustrations, particularly those of flying terns and gulls, the painter has appar- ently attempted to indicate shadow hy painting part of the underparts of these birds gray or brownish where they should be white. This is extremely confusing, particularly in a case like the Roseate Tern on page 143. The whole point about a Roseate Tern in summer dress is that it is whiter below (even pinkish sometimes) than the similar Arctic and Common terns, and yet here a Roseate labelled “summer” is pictured as gray below. This is a case where artistic effect should definitely be passed up in favor of formal color accuracy. Something has gone wrong with the flight pictures of Least, Semipalmated, and Western sandpipers on page 125; they are all far too dark. The flying Black Guillemot on page 149 presents an anatomical puzzle as regards the position of the wings. The head pictures of Ruff and Reeve on page 123 are useless for field identification, especially as no two males are ever quite alike in spring dress. If there is no room for a full-length or a flight picture, the birds are best left out. On the same page, I cannot understand why the Sharp-tailed Sandpiper is shown in summer dress, when by the authors’ own admission the bird is a fall visitor only, and the fall plumage is quite different. On page 94, we are left to assume that the unlabelled bird standing next to the Great Blue Heron is an immature bird of that species. Or is it a female? Or in winter plumage? The beginner needs to know. It is a pity that only the head of Cory’s Shearwater is illustrated, on the grounds that, as stated in the text, it has “plumage the same as the Pink-footed’s.” Not only is this an unscientific remark, as the birds belong to quite different species, but it obscures a piece of information vital for field identification, which is not mentioned anywhere in the text. The upper tail coverts of Cory’s Shearwater can be very pale, almost whitish at times, giving the effect of a narrow pale band above the dark tail tip, causing con- fusion with the Greater Shearwater. The Pink-footed Shearwater as illustrated, on the other hand, has the upper tail coverts even darker than the rest of the upperparts. The text needs to be tightened up in this case, too, and it should be pointed out that the best field mark for telling Cory’s and Greater shearwaters apart is not the pale band on the tail but the contrast between dark cap and light cheeks in the Greater. With regard to price, I think that $2.95 for the paper cover edition of this book represents unparalleled value for money. It is incredible that a book with over 150 pages of colored illustrations should sell for under three dollars. Furthermore, the size of the book is another selling point. Most field guides today are small, but still are too large to fit into the pockets of many jackets without some squeezing. In this book, the use of a soft cover reduces its dimensions all round, and its thickness is less than three quarters of an inch. It thus fits comfortably into any but the smallest pockets. In conclusion, in spite of some drawbacks, this is a really excellent book, and I heartily commend it. It will not replace the older field guides, because they contain additional features. Rather, it should be used to complement them, because it, likewise, contains features which they lack. It is so cheap that everyone can afford to buy it in addition to their other books. As to that inevitable, awkward question, “If you only had room for one guide, which one would you take?,” I will sidestep it by saying that I usually take more than one guide with me in any case. I suggest that every field birdman makes sure that he has a spare pocket large enough for Birds of North America. — Stuart Keith June 1967 Vol. 79, No. 2 ORNITHOLOGICAL LITERATURE 255 The Birds of Shakespeare, By James Edmund Halting. Including Of Men and Birds: Prolegomena to the Birds of Shakespeare. By Grundy Steiner. Argonaut Inc., Chicago, 1965: X 9M-> in., xxxviii -f 321 pp., 33 illus., 1 table. $7.50. The re-issue of “The Birds of Shakespeare” by J. E. Harting is an important event for all students of the poet. This book, first published in 1871 and long out of print, not only was the first complete survey of the subject but also remains the best. In making Harting’s study again accessible, the Argonaut Press has rendered a valuable service. Emphasis in the book is placed upon the poet’s knowledge of falconry. This is sug- gested in the frontispiece, where the fine figure of a Peregrine Falcon drawn by Wolf, the famous German artist, has been superimposed upon the Chandos portrait. A wealth of further engravings throughout the hook illustrates the subject at hand. Nine chapters deal with birds in a natural grouping. Following passages containing allusion to the eagle and other large birds, the author proceeds to what is perhaps his most valuable chapter, “Hawks and Hawking.” Quotations accompany explanation of the falconer’s jargon — tower, point, pitch, seel, watch, tire, and others, terms which came naturally to the poet. Later, in Chapter 7, the author passes to the complementary theme, “Game-birds and ‘Quarry’ flown at by Falconers.” Not least interesting here are quota- tions from royal household accounts showing an astonishing variety of table birds with the price paid for each. In his prefatory essay, “Of Men and Birds,” Professor Steiner of Northwestern Uni- versity reviews the role of birds among Greeks and Romans to emphasize the force of tradition in Shakespeare’s time. He remarks the extent to which the poet leans toward contemporary taste rather than to ornithological fact. He believes rightly that the plays reflect “a preponderance of tradition over observation.” Mr. Harting is kinder to Shakespeare than to his own contemporary, Alfred Tennyson. Allusions to birds by the laureate, he writes elsewhere, tend to prove that he had “neither a good eye for colour nor a good ear for bird music,” that in short, Tennyson was “inferior to many English poets who have preceded him” {The Zoologist, 1883, p. 145). But whatever its faults, all of them minor, Harting on Shakespeare’s birds is admirable throughout. Here is a reprint that every lover of birds and poetry should own. — Thomas P. Harrison Birds of Europe. Illustrations by John Gould. Text by A. Rutgers. Barnes & Noble, New York (first published by Methuen & Company, London), 1966: 7M.> X 9% in., 320 pp., 160 col. pis. $15.00. This is not really a book in the usual sense but a well-reproduced selection of litho- graphs that first appeared in Gould’s “The Birds of Europe” (1837) and “The Birds of Great Britain” (1862-73). Opposite each plate is a page of brief text, written for this volume, sometimes describing the species shown and giving a little information on habitat, behavior, nesting habits, and vocalizations. Strangely lacking is a preface or any intro- ductory material other than a table of contents. Nowhere is there one word about the author of the text, the sources of his information and the objectives of his presentation; and worse still, not one word about John Gould (1804-1881). Except for one dated quotation (p. 1) from The Birds of Europe, the reader has no way of knowing how long ago the lithographs were first published. The only information about Gould — and most inadequate — is on the front flyleaf of the jacket. Here the publishers give a few laudatory generalities about Gould’s work and mention the volumes from which the present litho- graphs were taken, but give no dates and state that successive volumes will cover Gould’s work on Asia, Australia, New Guinea, and South America. Hopefully they will he more 256 THE WILSON BULLETIN June 1967 Vol. 79, No. 2 than “non-books” such as this one. Much as the plates from Gould’s works, all of them rare, are welcome, they should he given historical perspective. — Olin Sewall Fettingill, Jh. ffuGS OH People? By Wheeler McMillen. Appleton-Century, New York, 1965: 5% X 8^/4 in., xi + 288 pp. $4.95. The jacket of this hook includes the subtitle “A Reasoned Answer to Opponents of Pesticides”; this should he enougli to forewarn the reader that a polemic is forthcoming. The author is an experienced agricultural writer who has had a long and distinguished eareer of service. He begins with an intimate hut somewhat clumsy description of the antics of Timmy, the titmouse, on the author’s breakfast terrace. This gambit is appar- ently designed to assure us of the author’s deep and abiding concern for wildlife. The effect on me was somewhat uncertain and my unallayed suspicions were confirmed in the third chapter when the real target of the hook is brought to focus: it is, of course, Rachel Carson and “Silent Spring.” It is odd that an excellent and more recent review ( Rudd’s “Pesticides and the Living Landscape”) should he overlooked hy the author. This is perhaps a good measure of the continuing effectiveness of Miss Carson’s role as the protagonist to the pesticide industry. In attempting to construct a rebuttal to Silent Spring, Mr. McMillen’s principal stratagem is to balance the continued need for pesticides to sustain production of food, fiber, and timber against the risks of damage to fish and wildlife. This position is undeniably one of great inherent strength; however, the author misjudges his material. To begin with, he fails to understand that threats to the robust success story of American agriculture are not likely to catch our imagination with half the force of the continued threats to an already depleted and beleaguered wildlife resource. Furthermore, the success story is poorly told. The author attempts to pull in an impressive assortment of specifics to set up his arguments. He is not deft in doing so and misses many excellent opportunities (as on p. 46) in describing biological control of the Klamath weed. He refers (p. 46) to the weed as “spread over several hundred thousand acres of once-good native pastures in Oregon, Idaho, Montana, Washington, and Nevada . . .”. By failing to check his sources carefully, the author has missed his mark by a fifteen-fold under- estimate; actually, more than 5 million acres were affected by the Klamath weed! There are many other examples where the author’s lack of precision destroys the impact of his argument (as on p. 43) : “The predatory insects, which make their living hy destroying other species . . .”. Secondly, the author shows a startling lack of ecological perspective in his failure to understand that the principal threat of pesticides to fish and wildlife is an indirect one, namely, through the aetion of hio-accumulation. For example, in discussing the Missis- sippi River fish kill ( p. 159) he asks “Could pollutions from higher up in the Mississippi and Missouri Valleys have acquired deadly effect only after they had reached so near to the big river’s mouth?”. Lastly, the author fails to understand that, if the national challenge of the past century was to attain an adequate standard of living for all, the challenge of the coming century will be to preserve the quality of the environment. The author’s view of man’s relationship to his environment is summed up in a concluding chapter on “What Needs to Be Done.” His response is “We should proceed to master our environment.” One cannot help but wonder what room would be left for “bugs” and other forms of wildlife in a “mastered” environment. — Daniel Q. Thompson This issue of The Wilson Bulletin was published on 5 June 1967 TfieWlsotiBulletin PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W. VA. VOL. 79, No. 3, SEPTEMBER 1967 PAGES 257-368 MUJ. COIvlP. ZOOL. library OCT 1 1 1967 HARVARD UNIVERSITY The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President — Aaron M. Bagg, Farm Street, Dover, Massachusetts. First Vice-President — H. Lewis Batts, Jr., Dept, of Biology, Kalamazoo College, Kalamazoo, Michigan. Second Vice-President — William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. Secretary — Jeff Swinebroad, Dept, of Botany & Zoology, Douglass College, Rutgers Univ., New Brunswick, New Jersey. Treasurer — C. Chandler Ross, Academy of Natural Sciences, 19th and Parkway, Philadelphia, Pennsylvania. Elected Council Members — Pershing B. Hofslund (term expires 1968) ; Kenneth C. Parkes (term expires 1969); Andrew J. Berger (term expires 1970). Membership dues per calendar year are: Sustaining, $10.00; Active, $5.00. 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. 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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 $5.00 per year. Single copies, $1.25. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at $1.25 each) and may be orderd 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. Allen Press, Inc., Lawrence, Kansas LltjKAKY OCT 1 1 1967 HARVARD THE WILSON BULLETINs'^y A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society Vol. 79, No. 3 September 1967 Pages 257-368 CONTENTS Ecology of the Nesting Birds of the McCurtain Game Preserve, Oklahoma William A. Carter 259 Observations on Bird Distribution and Feeding Assemblages Along THE Rio Callaria, Department of Loreto, Peru Jared M. Diamond and John W. Terborgh 273 Reproductive Success of Red-Winged Blackbirds in North Central Oklahoma Stephen V. Goddard and Veryl V. Board 283 Behavioral Stereotypy in Birds Peter H. Klopjer 290 Some Courtship Displays of the Golden-winged Warbler James Baird 301 Food and Feeding Habits of Autumn Migrant Shorebirds at a Small Midwestern Pond William S. Brooks 307 ClCONlA MALTHA AND GrUS AMERICAI^A FROM THE UpPER PlIOCENE OF Idaho /. Alan Feduccia 316 Seed-size Preference in Chickadees and Titmice in Relation to Ambient Temperature Becky A. Myton and Robert W. Ficken 319 Additional Observations on the Structure of Unusual Feather Tips Alan H. Brush 322 The Influence of Vocal Behavior on the Performer’s Testicular Activity in Budgerigars (Melopsittacus UNDULATUS) Barbara F. Brockway 328 An Improved Cage Design for Fxperimentation with Passeriform Birds Elden W. Martin 335 General Notes flightle:ss gheen-winged teal in southeast MissoiiKi John P. Rogers 339 DISGORGING OF FOOD BY WOOD DUCKS — Paid A. Stewort 339 15UFF-BKEASTED SANDI’II’EK IN NOH'l II WESTERN OHIO Richard S. Phillips 340 EGG TEETH AND HATCHING METHODS OF THE LONG-BILLED CURLEW Dennis M. Forsythe 340 FOREIGN EGGS IN NESTS OF CALIFORNIA GULLS Kees Vermeer 341 bonararte’s gull feeding on walnut meat Robert C. Frohling 341 PREDATION BY CHUCK-WILl/s-WIDOW UPON MIGRATING WARBLERS Oscar T. Owre 342 JOSSELYN VAN TYNe’s COMMON NIGHTHAWK NESTING RETURN Andrew J. Berger 343 RETARDED OR ARRESTED CRANIAL DEVELOPMENT IN MYIORNIS ECAVDATUS Raymond McNeil and Aida Martinez 343 THE GAl’ING RESPONSE OF NESTLING BANK SWALLOWS George W. Fllllc 344 SEASONAL VARIATION IN BILL LENGTH OF HOUSE SPARROWS Gary G. Packard 345 UNUSUAL ACTIVITIES OF A HOUSE SPARROW^ AND A BLUE JAY AT A TUFTED TITMOUSE NEST Kenneth W. Prescott 346 EXTRALIMITAL BREEDING OF PAINTED BUNTINGS IN FLORIDA John G. Ogden and Frank L. Ghapman 347 GOLDFINCH ACCEPT YOUNG AFTER LONG AND SHORT INCUBATION Larry G. Holcomb 348 NEW STATUS FOR THE RUFOUS-CROWNED SPARROW IN UTAH .. Roland H. Waller 348 The President’s Page Aaron M. 350 Ornithological News 351 Ornithological Literature 352 Alfred M. Bailey and Robert J. Niedrach, The Birds of Golorado, reviewed by Olin Sewall Pettingill, Jr.; Desmond Nethersole-Tliompson, The Snow Bunting, reviewed by Margaret M, Nice; Robert S. Arbib, Jr., Olin Sewall Pettingill, Jr., and Sally Hoyt Spofford, Enjoying Birds around New York Gity, reviewed by Geoffrey Carleton; Sberwin Carlquist, Island Life: A Natural History of the Islands of the World, reviewed by Robert I. Bowman; En- vironmental Pollution Panel, Presidents Science Advisory Committee, Restoring the Quality of Our Environment, reviewed by Daniel Q. Thompson. Proceedings of the Forty-eighth annual meeting Pershing B. Hojsluml 358 ECOLOGY OF THE NESTING BIRDS OF THE McCURTAIN GAME PRESERVE, OKLAHOMA' William A. Carter This paper reports an ecological investigation of the nesting birds of a virgin woodland area. Field studies during the summer of 1961 and 1962 were conducted in the McCurtain Game Preserve near Bethel, in south- eastern Oklahoma. The purpose of this paper is to describe the breeding bird populations of the major communities and to point to certain ecological relationships between these populations and their communities. Attention is directed to; (1) estimates of the breeding bird populations, (2) the type of habitats which these populations occupy for breeding and foraging terri- tories, (3) and the community structure at the western fringe of the oak-pine forest. This region is of particular interest since it represents a virgin forested area and is near the western limits of this formation. It is to be regretted that more detailed work has not been done in other biological fields within the river-bottom forests of the Preserve, as this association will soon be inundated by waters of the Broken Bow Reservoir. Construction of big dams, lumbering practices, and over-utilization by cattle and hogs in the river bottom areas of eastern Oklahoma are rapidly reducing the area of this biotic association and leaving the remainder unsuitable for many types of wildlife. THE MCCURTAIN GAME PRESERVE History of the Preserve.— The McCurtain Game Preserve includes 15,220 acres of mountainous land in north-central McCurtain County, Oklahoma. It is the only Okla- homa state-owned area of virgin oak-pine forest. According to P. R. Wheeler, director ot the Southern Forest Experiment Station, New Orleans, Louisiana (in litt.) there is ... no comparable area of virgin timber in the Southeastern (Forest Service) Region." Ins then, is a unique area for scientific research and one of high aesthetic value, e Preserve was placed under the administration of the Oklahoma Game and Fish Uepartment (now the Department of Wildlife Conservation) in 1927. Except for the loun ary fence and maintenance roads, no cultural or management techniques were undertaken on the Preserve until 1950. During that year, a block of 40 acres was enced in the central area of the Preserve to provide a holding pen for a turky restocking program. The Preserve has been protected from all forms of hunting and from fire except for small burns, since 1926. Cattle penetrate the area from the surrounding open’ range when flooding or vandalism damages the fences, however, their nuniliers arc small and they are promptly removed. No attempt is made to remove swine unless they become too numerous. ^ Contribution No. 425 from the Department of Zoology, Oklahoma State University 259 260 THE WILSON BULLETIN September 1967 Vol. 79, No. .3 Predator control, which has been maintained in the Preserve on a limited basis, has been limited to trapping of bobcats, gray foxes, coyotes, and wolves (?). Dogs that may stray into the Preserve are caught and returned to their owners. The U.S. Army Corps of Engineers began survey work in the virgin river-hottom areas of the Preserve for the Broken Bow Reservoir during the summer of 1963. The opening of the Broken Bow Reservoir for public recreation will have a marked effect on the remote Preserve. Inundation will destroy the most unique areas of the Preserve, the virgin river-hottom hardwood forest. Enforcement of trespassing and hunting regula- tions and wilderness protection for the remainder of the Preserve will he made difficult as improvement of roads leading to the lake area increase the number of visitors. Description of the Preserve. -^Jhe Preserve lies in the southern portion of the Ouachita Uplift. The terrain varies from moderately rugged or rather steeply rolling, to precipi- tous. Characteristically it is composed of rough ridges. Elevations vary from 561 feet above sea level along the Mountain Fork of the Little River to 1,363 feet on Pine Mountain in the east central part of the Preserve. Drainage of the Preserve is part of the Mountain Fork River system. The soil materials in the valleys consist of shales and fill material; the ridges are composed of sandstones, shales, and slate. Streams of high gradient are actively cuUing the narrow flood plains. Bottomland soils are leached, poorly drained, and relatively infertile. There are small prairie openings and areas that support savannah on soils with a higher clay content. Much of the mountain area is rough, stony land, with some of the formations dipping 60 degrees or more from the horizontal. The exposed edges of the rocks enable tree roots to grow between the layers. This, together with the high precipitation, results in superior forest sites. By contrast, in areas where shallow soils are on horizontally bedded rocks, very poor forest sites result. Ridges of the White Oak and Little White Oak mountains fall into this classification. Shale hands across the mountain slopes produce open or savannah areas with increased grass ground-cover. The Ouachita Mountains of Oklahoma were first studied geologically by Honess (1923) with more recent detailed work in Beavers Bend State Park (Pitt and Spradhng, 1963) a few miles south of the Preserve. Surface or near surface rocks which influence the soil and vegetative associations within the Preserve include formations from the Ordovician period to the Recent geologic epoch. These include: (1) Alluvium Forma- tion of the Recent characterized by recent stream deposits of sand, silt and clay; (2) Trinity Formation of the Cretaceous; (3) Stanley Shale Formation of the Mississipian ; (4) Arkansas Novaculite Formation, of which the Upper Division is of the Mississippian period, the Middle Division between the Mississippian and Devonian periods, the Lower’ Division of the Devonian; (5) Missouri Mountain Shale Formation of the Silurian; (6) Blaylock Sandstone Formation of the Silurian; (7) Polk Creek Shale Formation of the Ordovician; and (8) Bigfork Chert Formation of the Ordovician. The Stanley Shale Formation is the most extensive formation in the Preserve. The Preserve is located in the area of Oklahoma which receives the highest annual rainfall. Approximately 75 per cent of the rainfall occurs during the growing season. Records for a 10-year (1954-1963) average monthly rainfall are shown in Table 1. Ex- tremes for the 10-year period show a high of 12.42 inches in October 1954 and a low of 0.31 inches in October 1963. Rivers and streams in the area may rise rapidly m response to heavy rainfall during short periods of time, hut the run-off is rapid Ihe 10-year temperature records showed the highest monthly average maximum of 93 1 m July and the lowest monthly average minimum of 28 F in January, as shown in Table . A 24-year record showed an average annual frost-free period of about 233 days with W illiam A. Carter NESTING BIRD ECOLOGY 261 Table 1 Ten-Year Average (1954-1963) OF Climatological Data Precipitation totals Average Monthly Temperature (°F) Maximum Minimum January 2.80 51.48 27.78 February 2.99 57.31 33.19 March 3.96 63.55 38.03 April 4.36 74.02 49.26 May 5.35 81.60 57.75 June 3.08 87.46 64.06 July 4.88 92.66 68.59 August 4.33 92.45 67.17 September 4.29 86.28 60.78 October 4.38 76.13 51.07 November 3.48 63.43 38.10 December 3.36 54.66 32.56 the last killing frost usually occurring the third week in March, and the first killing frost in the fall occurring about the second week in November. Published records of the U.S. Department of Commerce (1954-63) were consulted for all climatic data. The Austroriparian Biotic Province (Dice, 1943), characterized by subclimax pine forests within the eastern deciduous forests, is found within this major climatic area. The Preserve is located in the western limits of this Province. The vegetative units within the Preserve may be delimited according to the topographic and soil character- istics of the site. Lindzey, studying the deer in the Preserve (1950), recognized six game (habitat) types within the Preserve. The steep north slopes and the protected ravines are characterized by white oak iQuercus alba), red oak iQuercus rubra), and flowering dogwood iCornus florida) . The ridges are characterized by mature stands principally of short-leaf pine iPinus echinata) , hut include post oak iQuercus stellata) , white oak iQuercus alba), and blackjack oak iQuercus marilandica) . The south slopes have essentially the same composition as the ridges. A large portion of the Preserve manifests an intermediate condition, with variable sites which show a composite of other upland areas. The virgin river bottom hardwood forests are dominated by holly illex opaca) , white oak iQuercus alba), sweetgum i Liquidambar styraciflua) , hickory iCarya sp.), ash (Fraxinus sp.), and baldcypress iTaxodium distich um) , with cane i Arundinaria gigantea) , spicebush iLindera benzoin), and some panic grasses iPanicum spp.), for ground cover. The stream bottom woodlands typically have a composition similar to that of the north slopes. It is of major importantce to recall that the avian habitats are essentially of the same life-form in all areas of the Ouachita Uplift. Out- side of the Preserve, however, mature virgin stands are found in very limited areas. METHODS The present study is an attempt to obtain the absolute abundance or the actual avian breeding populations of sample areas and to project these figures for an estimate of the total breeding bird populations for the Preserve. As 262 THE WILSON BULLETIN Sc|itcml)er 1967 Vol. 79, .No. :i Table 2 Dominants and Codominants of tup: Rived Bottom Forest* Species Frequency of occurrence ( per cent ) Basal area (sq. ft.) (per cent) American holly (//ex opaca) 34 12.4 19.7 White oak {Quercus alba) 19 11.7 18.5 Sweetgum i Liquidamhar styracijiua) 9 13.2 20.9 Mockernut Hickory iCarya tomentosa) 8 3.7 5.9 Sourgum iNyssa sylvatica) 5 6.1 9.6 A.'ih \Fraxmus sp.) 5 0.9 1.4 Baldcypress (Taxodium distichum) 4 6.8 10.8 Hornheam iOstrya virginiana) 3 - - Ironwood (Carpinus caroliniana) 3 0.6 0.9 Total 63.1 * Plant nomenclature taken from Petrides, 1958. this study was primarily concerned with obtaining the most dependable re- sults possible, a combination of various census techniques was employed. On the basis of field reconnaissance and a review of aerial photos and topographic maps, three areas were selected for intensive study. This selec- tion was based on the following points: areas were (1) representative of the three major plant communities in the Preserve; (2) not disturbed by roads, fence lines, or other maintenance improvements of the Preserve; (3) of uniform life-form and were surrounded by identical community type in order to eliminate edge effect; and (4) of adequate size for uniform plots. The boundaries of these areas were marked. The size of each plot was de- termined by use of steel tape, compass, and aerial photographs. A sketch map of each plot was used each time an area was censused. These maps in- cluded any distinctive landmark which helped pinpoint the exact locality. Field data were noted on the maps to show approximate locations of singing males, active nest sites, young out of the nest, adults carrying food, family groups, or any other behavioral activities or signs that would indieate nesting. The areas were censused from 5 am to about 8 am. I found that the activity of singing males for most species had decreased by 7:30 am to 8:30 AM to the point that counts were invalid. However, observations on other activities associated with breeding could be made after that time. The belt transect sampling method (Weaver and Clements, 1929; Lutz, 1930 ) was used to determine species composition of trees and shrubs in the sample plots. The width of the transect lines was 20 meters for trees and two meters for shrubs. In the upland samples with a large area of uniform com- munity type, the length of the transect line was inereased until the percentage composition was not varied when the last segment was added. The river W illiai Carter A. NESTING BIRD ECOLOGY 263 Table 3 Undekstoky Plants of the River Bottom Forest* Frequency of occurrence Species (per cent) Ironwood iCarpinus Carolinian a) 16 Ward willow {Salix caroliniana) 14 Mockernut hickory iCarya tomentosa) 9 Hornbeam iOstrya virginiana) 9 Buttonbush {Cephalanthus occidentalis) 6 Grape iVitis sp.) 5 Flowering dogwood (Cornus florida) 3 Sweetgum (Liquidambar styraciflua) 2 Red oak {Quercus rubra) 2 Baldcypress {Taxodium distichiim) 2 * d.b.h. less than 4"; 1 m high. bottom and stream bottom plots were sampled by three transect lines running at right angles to the plots. BIRD POPULATIONS AND THE PLANT COMMUNITIES The avian habitats of the Preserve reflect the basic structure of the domi- nant vegetation, rather than the species composition of individual plant as- sociations— a point well demonstrated by Pitelka ( 1941 ) lor the North American bird fauna. Considering the distribution of local bird species, the predominant habitats, preferred for breeding activities, are upland forests, river bottom forests, and stream bottom woodland. The river bottom community. — The study area of this habitat type in- cluded that portion of the river bottom east of the Mountain Fork River from the low-water bridge north to the Preserve fence. The 35-acre study area was located in Section 4, R25E, T3S. Elevation was 560 feet above sea level. One-half mile of edge occurs along the river. The closure of the forest crown cover of this community varies from 50 to 100 per cent. The frequency of occurrence and basal area of the dominant and codominant trees is given in Table 2. The frequency of occurrence of the common understory plants is given in Table 3. The ground cover is sparse, composed chiefly of: Panicurn sp., Smilax spp., spicebush [Liiidera benzoin), and cane { Arundinaria gigantea ) . A high percentage of the river bottom forest floor is open, bare ground, or covered with river drift materials. The river bottom community is the most important one of the Preserve for the study of bird ecology as it supports the greatest total biomass. The floral and faunal composition make this a unique feature of the Preserve. 264 THE WILSON BULLETIN September 1967 Vol. 79, No. 3 Nesting Birds Table 4 OF THE River Bottom Forests Species Pairs/100 acres 1961 Pairs/ 100 acres 1962 Average Projected estimate ( 200 acres ) Turkey Vulture + + + Wood Duck 1 1 1.0 Red-shouldered Hawk Bobwhite 1 + 1 1 2.0 + Turkey + + + Yellow-hilled Cuckoo 5.7 5.7 5.7 11.4 Barred Owl 8.6 2.9 5.7 11.4 Chuck-will’s-widow 8.6 2.9 5.7 11.4 Chimney Swift + + + Ruhy-throated Hummingbird 2.9 2.9 5.8 Belted Kingfisher + + + Pileated Woodpecker 2.9 2.9 2.9 5.8 Red-hellied Woodpecker 5.7 5.7 5.7 11.4 Hairy Woodpecker 5.7 2.9 4.3 8.6 Downy Woodpecker 2.9 2.9 2.9 5.8 Great Crested Flycatcher 8.6 2.9 5.8 11.6 Acadian Flycatcher 14.3 11.4 12.9 25.8 Eastern Wood Pewee 5.7 5.7 5.7 11.4 Blue Jay + + + Common Crow 1 1 1 2.0 Carolina Chickadee 11.4 11.4 11.4 22.8 Tufted Titmouse 5.7 8.6 7.2 14.4 White-breasted Nuthatch 8.6 2.9 5.7 11.4 Carolina Wren 8.6 8.6 8.6 17.2 Wood Thrush 2.9 2.9 2.9 5.8 Blue-gray Gnatcatcher 11.4 2.9 7.2 14.4 White-eyed Vireo 25.7 17.1 21.4 42.8 Red-eyed Vireo 28.5 25.7 27.1 54.2 Blaek-and-white Warbler 8.6 8.6 8.6 17.2 Prothonotary Warbler 1 1 1 2.0 Swainson’s Warbler 1 1 1 2.0 Worm-eating Warbler 3 2 2.5 5.0 Parula Warbler 8.6 11.4 10.0 20.0 Cerulean Warbler 2.9 2.9 2.9 5.8 Ovenbird 5.7 2.9 4.3 8.6 Louisiana W'aterthrush 8.6 8.6 8.6 17.2 Kentucky Warbler 11.4 8.6 10.0 20.0 Yellow-breasted Chat 2 2 2 4.0 Hooded Warbler 14.3 17.1 15.7 31.4 American Redstart 20.0 14.3 17.2 34.4 Cardinal 8.6 5.7 7.2 14.4 Indigo Bunting 2.9 2.9 2.9 4.8 Totals (36 species, +6) 279 219 248 502 William A. Carter NESTING BIRD ECOLOGY 265 Table Dominants and Codominants of 5 THE Stream Bottom Forest Species Frequency of occurrence ( per cent ) Basal area (sq. ft.) ( per cent ) White oak {Quercus alba) 17 11.0 14.1 Shortleaf pine i Pinas echinata) 17 23.1 29.6 Mockernut hickory iCarya tomentosa) 16 11.4 14.6 Sweetgum ( Liquidambar styraciflua) 14 13.0 16.7 Ironwood iCarpinus caroliniana) 7 2.7 3.4 Sourgum (Nyssa sylvatica) 6 4.9 6.3 Red oak (Quercus rubra) 4 2.8 3.6 Red maple (Acer rubrum) 4 1.2 1.6 Hornbeam (Ostrya virginiana) 4 0.7 0.9 Swamp oak (Quercus bicolor) 2 0.7 0.9 Pignut hickory iCarya glabra) 2 1.0 1.3 Winged elm (Ulmus alata) 2 1.5 1.9 Sycamore (Platanus occidentalis) 2 2.9 3.7 Red mulberry (Morus rubra) 2 1.0 1.3 Ash (Fraxinus sp.) 2 0.6 0.7 Red cedar (Juniperus virginiana) 1 0.5 0.6 Total 78.0 Studies in various areas of this community other than the study area show remarkable uniformity in proportions of species. There is very little dis- parity between the counts made during the two summers. The estimates of species in the study area and the projected estimates for the 200 acres of this community are given in Table 4. A plus sign ( + ) is used to indicate species which nested outside the study area in this habitat and species fre- quently observed but not definitely known to breed in the habitat. The figures for the average number of pairs are derived from the populations in the study areas and augmented by data from observations in the same habitat but outside the study area. The stream bottom community. — The stream bottom community study area consisted of a 32-acre plot along Panther Branch in Sections 4 and 5, R25E, T3S. The area averaged 130 yards wide with the stream bed in the center and the outer boundaries more or less paralleling the stream bed. Sufficient width was allowed between these outer boundaries and the slopes to avoid edge effect. The closure of the forest cover ranged from 50 to 75 per cent and was generally uniform. The frequency of occurrence and basal area of the dominant and codominant trees is given in Table 5. The frequency of oc- currence of the common understory plants is given in liable 6. This community 266 I HE WILS()\ BULLETIN Septemher 1967 Vol. 79, No. 3 Table 6 Unuekstoky Plants of tup: Sthp:am IJottom Forest* Frequency of occurrence Species ( per cent ) Ironwood {Carpinus caroliniana) 31 Red cedar (Juniperus virginiana) 16 Sweetgum ( Liquidambar styraciflua) 11 Witch-hazel ( Hamamelis virginiana) 10 Flowering dogwood (Cornus jlorida) 9 Hornbeam iOstrya virginiana) 1 Red oak iQuercus rubra) 3 White oak iQuercus alba) 3 Shortleaf pine iPinus echinata) 2 Sourgum (Nyssa sylvatica) 1 Mockernut hickory iCarya tomentosa) 1 Common spicebush (Lindera benzoin) 1 Winged elm iUlmus alata) 1 * d.b.h. less than 4"; 1 m high. had the best ground cover of the three major habitats of the Preserve. Andropo^on spp. formed about 75 per cent of the non-woody ground cover. Paniciirn spp. and seedlings of the various woody species formed most of the remaining living ground cover. Heavy litter covered most of the space between plants so that very little bare ground was exposed. The nesting bird populations showed a species composition intermediate between those of the moist river bottom and the drier uplands. No birds were restricted to this habitat. The estimate of species in the study area and the projected estimate for the 1,100 acres of this community in the Preserve are given in Table 7. The upland community. — The upland Oak-Pine community study area was located in Sections 2 and 11, R25E, T3S. The 30-acre area was along the section line on the east side of the given sections. Crown closure of this area was from 70 to 100 per cent. The area is typical of the intermediate areas of the Preserve, that is, those with moderate slopes. Lindzey (1950) recognized four game types in the upland community. How- ever, field observations showed no significant variations in the avian species distribution in these four types. Significant divergence of species composition did occur on White Oak and Little White Oak mountains, but the remoteness of these areas made it impossible to adequately sample the bird populations there. The frequency of occurrence and basal area of the dominant and codominant trees are given in Table 8. The frequency of occurrence of the common understory plants is given in Table 9. The ground cover varied Williai Carter A. NESTING BIRD ECOLOGY 267 Nesting Birds Table 7 1 OF THE Stream Bottom Forests Species Pairs/ 100 acres 1961 Pairs/ 100 acres 1962 Average Projected estimate (1,100 acres ) Turkey Vulture + + + Broad-winged Hawk 3.1 + 1 11 Sparrow Hawk + 3.1 1 11 Bobwhite 3.1 + 3.1 34 Yellow-billed Cuckoo 3.1 3.1 3.1 34 Screech Owl 3.1 + 1 11 Chuck-will’s-widow + + + Chimney Swift + + + Ruby-throated Hummingbird 1 1 11 Pileated Woodpecker 1 1 1 11 Red-bellied Woodpecker + + Hairy Woodpecker 3.1 3.1 3.1 34 Downy Woodpecker 3.1 3.1 3.1 34 Great Crested Flycatcher 3.1 3.1 3.1 34 Acadian Flycatcher 9.4 6.3 7.9 87 Eastern Wood Pewee 9.4 9.4 9.4 103 Blue Jay 6.3 3.1 4.7 52 Common Crow + + + Carolina Chickadee 12.5 9.4 10.5 116 Tufted Titmouse 3.1 6.3 4.7 52 White-breasted Nuthatch 6.3 6.3 6.3 69 Carolina Wren 9.4 9.4 9.4 103 Wood Thrush + + Blue-gray Gnatcatcher 6.3 3.1 4.7 52 White-eyed Vireo 3.1 3.1 3.1 34 Red-eyed Vireo 18.8 18.8 18.8 207 Black-and-white Warbler 3.1 3.1 3.1 34 Parula Warbler 9.4 12.5 10.5 116 Pine Warbler 9.4 6.3 7.9 87 Ovenbird 3.1 3.1 3.1 34 Louisiana Waterthrush 3.1 6.3 4.7 52 Kentucky Warbler 3.1 + 3.1 34 Indigo Bunting + 3.1 3.1 34 Totals (27 species, +6) 140 126 136 1,491 from sparse Andropogon in the more open areas to exclusively pine needle and leaf litter in areas with dense crown cover. The virgin stands of mature short-leaf pine are the habitat of the Preserve’s two most unique permanent avian residents, the Red-cockaded Wood})ecker and the Brown-headed Nuthatch. Nice (1931) reported Red-cockaded Wood- peckers in 1925. This species was not recorded from the state again until 268 THE WILSON BULLETIN Septfiiil)er 1967 \ ol. 79, No. ;j 4\ble Dominants and Cooominants 8 OF THE UpLANIJ Forests Frequency of Basal area occurrence Species ( per cent ) (sq. ft.) (per cent) Sliortleaf pine iPinus echinata) 81 69.6 87.0 White oak ( Quercus alba) 10 2.9 3.6 Post oak (Quercus stellata) 7 6.6 8.4 Blackjack oak (Quercus marilandica) 2 0.2 0.25 Total 79.3 1954 (Baumgartner, 1954). The Recl-cockaded Woodpeckers were limited in distribution in the Preserve to areas with stands of large mature pine— d.b.h. 15 inches or more. Nest trees which I was able to locate averaged 17 inches d.b.h. Their habit of scaling the bark from the living pine for two feet above and below the entrance of the nest cavity and of puncturing a series of small holes to allow the pine pitch to ooze to the surface allows the nests to be located easily. The only nesting record for Oklahoma outside of the Preserve was reported in Robber’s Cave State Park near Wilburton in 1961 (Baumgartner, 1961). The Brown-headed Nuthatch was observed in Pushmataha County in 1920 (Nice, 1921) and was not recorded in Oklahoma again until 1953 (Baumgartner, 1954). Tom lessee, then the Preserve man- ager, reported this species nesting in a fence post on the Preserve on 11 March 1954 with young noted in late April. Other species found in the upland habi- tat are considered typical for the region. The estimates of species in the study area and the projected estimate for the 12,000 acres of this community type are given in Table 10. DISCUSSION Eleven species were nesting only in the river bottom habitat within the Preserve. No species were found using the stream bottom habitat exclusively for nesting. However, seven species were limited to the stream bottom and the river bottom — the more moist habitats within the Preserve. A total of eighteen species were limited to the two riparian woodland formations within the Preserve — the river bottom and the stream bottom communities. Of these eighteen species, seven are approaching their western limits of distribu- tion (AOU, 1957). The Wood Duck, Prothonotary Warbler, Louisiana Waterthrush, Swainson’s Warbler, and Cerulean Warbler are typical nesting species of the riparian habitats over their entire breeding ranges. The Oven- bird and the Worm-eating Warbler are typical woodland nesting forms over most of their range and are restricted to the riparian woodlands only in the William A. Carter NESTING BIRD ECOLOGY 269 Table 9 Understory Plants of the Upland Forests* Species Frequency of occurrence ( per cent ) Mockernut hickory (Carya tomentosa) 29 Post oak (Quercus stellata) 20 Blackjack oak {Quercus marilundica) 14 Flowering dogwood (Cornus floridu) 14 White oak (Quercus alba) 6 Shortleaf pine {Pinus echinata) 3 Common spicehush (Lindera benzoin) 2 Red oak (Quercus rubra) 2 * d.b.h. less than 4"; 1 m high. southwestern limits of their nesting distribution (AOU, 1957). Eour species were limited to the stream bottom and upland forests for their nesting activities within the Preserve. The intermediate character of the stream bottom communities was therefore emphasized by the nesting distribution pattern which showed an overlap of species from both the river bottom and the upland forests, as well as a mixed floral composition. The upland habitat was utilized by seven species exclusively for their nesting activities. Twenty-three species utilized all three of the major habitats in the Preserve for nesting activities. This pointed out the fact that a woodland habitat — regardless of its composition — was the only requirement for certain species with less specialized nesting niches. It was also noted that some of these species reached greater densities in one habitat than in the other. Nine species were considered to be rare within the Preserve. The follow- ing reasons are suggested to explain the limited occurrence of these nine species: The Wood Duck and Prothonotary Warbler populations were limited due to the lack of proper nesting cavities in trees along the river; the minimal numbers of Red-shouldered Hawks are attributed to their large territorial requirements and the limited area of suitable river bottom habitat; the Roadrunner, having recently invaded this region (Lowery, 1955), is reach- ing its eastern limits of distribution (AOU, 1957) ; the Red-cockaded Wood- pecker, being intimately associated with mature stands of pines, is limited by their distribution; the Brown-headed Nuthatch, Prothonotary Warbler, Swainson’s Warbler, Worm-eating Warbler, and Cerulean Warbler are ap- proaching the western limits of their nesting range (Griscom and Sprunt. 1957); and the Turkey populations, once extirpated from this area, have been reintroduced. 270 THE WILSON BULLETIN Sc[)tpnil»er 1967 Vol. 79, No. .1 Nesting Table 10 Birds of the Upland Forests Species Pairs/ 100 acres 1961 Pairs / 100 acres 1962 Average Projected estimate (12,000 acres) Turkey Vulture + + + Sparrow Hawk 1 1 1 20 Bobwhite + + Turkey + + + Yellow-billed Cuckoo 6/) 6.6 6.6 792 Roadrunner + + 4 Screech Owl + + + Chuck-will’s-widow + + Chimney Swift + + + Yellow-shafted Flicker + + Red-bellied Woodpecker 3.3 3.3 3.3 396 Red-headed Woodpecker 6.6 6.6 6.6 792 Hairy Woodpecker 3.3 + 3.3 396 Downy Woodpecker + 3.3 3.3 396 Red-cockaded Woodpecker + + 7-10 Great Crested Flycatcher 6.6 6.6 6.6 792 Eastern Wood Pewee 9.9 9.9 9.9 1,188 Blue Jay 3.3 6.6 5.0 600 Common Crow + + + Carolina Chickadee 6.6 6.6 6.6 792 Tufted Titmouse 6.6 6.6 6.6 792 White-breasted Nuthatch 9.9 6.6 8.3 996 Brown-headed Nuthatch + + + Carolina Wren 3.3 6.6 5.0 600 Wood Thrush + 6.6 6.6 792 Blue-gray Gnatcatcher 3.3 6.6 5.0 600 Red-eyed Vireo 9.9 19.9 14.5 1,740 Black-and-white Warbler 3.3 + 3.3 396 Parula Warbler + + + Yellow-throated Warbler + + + Pine Warbler 9.9 13.2 11.5 1,380 Prairie Warbler + + Ovenhird 3.3 3.3 3.3 396 Scarlet Tanager 3.3 3.3 3.3 396 Summer Tanager 3.3 6.6 5.0 600 Indigo Bunting 3.3 + 3.3 396 Chipping Sparrow + + + Total (35 species, +2) 107 130 128 15,262 William A. Carter NESTING BIRD ECOLOGY 271 The densities of a few species within the Preserve were lower than those outside of the Preserve. Among these, personal observations indicated that the Chipping Sparrow, Bobwhite, Cardinal, Blue Jay, and Common Crow were more tolerant of the open areas created by the activities of man. Al- though common outside, the Mourning Dove, House Sparrow, Orchard Oriole, Brown-headed Cowbird, Eastern Bluebird, and Starling were found only in limited numbers in the small disturbed areas around the manager’s home and barns. These species were never recorded in any other part of the Pre- serve. The population of ground nesting species was suppressed by the de- struction of the ground cover, nests, and young by the activities of swine. SUMMARY Field studies of the nesting birds of the McCurtain Game Preserve, McCurtain County, Oklahoma, were conducted during the summers of 1961 and 1962 in the months of June, July, and early August. Intensive studies were made in three areas representative of the major habitats of the Preserve. Data derived from these study areas were aug- mented by less intensive surveys within each of the habitats at various locations over the Preserve. The river bottom community supported the highest population of nesting birds (248 pairs per 100 acres) and the greatest number of species (36, plus six others possible). Eleven species utilized the river bottom habitat exclusively for nesting activities. The stream bottom community supported 136 pairs per 100 acres with 27 species (plus six others possible). The upland community supported 128 pairs per 100 acres with 35 species (plus two others possible). The total projected breeding bird population for the 13,300 acre virgin woodlands of the Preserve was 17,255 pairs composed of 56 species. Two of these species, the Red-cockaded Woodpecker and the Brown-headed Nuthatch are limited to the mature virgin pine areas of the Preserve in Oklahoma. The activities of swine suppress the population of ground nesting birds in the Preserve. The unique attributes of the virgin hardwood forest of the river bottom will be destroyed by waters of the Broken Bow Reservior now under construction. Steps should be taken to assure adequate protection for the remaining virgin woodland areas of the Preserve. ACKNOWLEDGMENTS Appreciation is expressed to my major adviser. Dr. F. M. Baumgartner, who has freely given his time and counsel during the course of this research project. The results reported here represent part of a dissertation submitted in partial fulfillment of the requirements for the Ph.D. at Oklahoma State University. I wish to thank the admin- istration of the Oklahoma Department of Wildlife Conservation for permission to carry out the field study and use the facilities in the Preserve. Special thanks are due Mr. Eugene Woods, Preserve manager, and Mr. Glen Scott, former assistant, and their families for cooperation and courtesies extended during my stay in the Preserve, 1 am indebted to Drs. G. A. Moore and H. W. Reno for reading early drafts of the manu- script. LITERATURE CITED Amkrican Ornithologist’s Union 1957 Check-list of North American birds. 5tb Ed. Baltimore, Maryland. 272 THE WILSON BULLETIN Se])temher 1967 Vol. 79, No. 3 lUuMGAKTNEH, F, M. 1954 Southern Great Plains Region. Audubon Field Notes, 8:260. 1961 Southern Great l^lains Region. Audubon Field Notes, 15:478. Dice, L. R. 1943 The liiotic provinces of North America. Univ. of Michigan J^ress, Ann Arlior. Gkiscom, L., and a. Sprunt, Jr. 1957 The warhlers of America. Devin-Adair Go., New York. Honess, C. W. 1923 Geology of the Southern Ouachita Mountains of Oklahoma. Okla. Geological Survey, Bull. 32, Parts 1 and II. Lindzey, J. S. 1950 The white-tailed deer in Oklahoma. Okla. Game and Fish Dept., Oklahoma City. Lowery, G. H., Jr. 1955 Louisiana birds. Louisiana State University Press, Baton Rouge, Louisiana. Lutz, H. J. 1930 The vegetation of Heart’s Content, a virgin forest in northwestern Pennsyl- vania. Ecology, 11:1-29. Nice, M. M. 1921 The Brown-headed Nuthatch in Oklahoma. Condor, 23:131. 1931 The birds of Oklahoma. Rev. ed. Univ. of Oklahoma Biol. Survey 3:1-224. Petrides, G. a. 1958 A field guide to trees and shrubs. Houghton Mifflin Co., Boston. PiTELKA, F. A. 1941 Distribution of liirds in relation to major biotic communities. Amer. Midland Nat., 25:113-137. Pitt, W. D., and C. B. Spradling 1963 Geology of Beavers Bend .State Park. In Beavers Bend .State Park. Okla. Geological Survey Guide Book XI. U.S. Dept, of Commerce 1954-1963 Climatological Data. Oklahoma Sections. U.S. Gov’t. Printing Office, Washington, D.C. Weaver, J. E., and F. E. Clements 1929 Plant ecology. McGraw-Hill, New York. DEPARTMENT OF BIOLOGY, EAST CENTRAL STATE COLLEGE, ADA, OKLAHOMA, 7 FEBRUARY 1966. OBSERVATIONS ON BIRD DISTRIBUTION AND FEEDING ASSEMBLAGES ALONG THE RIO CALLARIA, DEPARTMENT OF LORETO, PERU Jared M. Diamond and John W. Terborgii This paper presents a summary of bird observations made in late July and early August. 1963, along the Rio Callaria, a small tributary of the Ucayali in the Department of Loreto, Peru. The Rio Callaria flows westward from the Brazilian border region to its confluence with the Ucayali at ap- proximately o°o'S and 74°38'W. From this point we travelled by dugout canoe some 20-30 miles upstream and returned. Observations of birds were made from the river and its banks and on excursions into the flanking forests. The relative abundance of 88 species in each of three distinct vegetational zones is given along with incidental notes and a description of two mixed assemblages of birds observed in feeding trees. ECOLOGICAL ZONATION OF BIRDLIFE So far as we were able to ascertain, the terrain in the vicinity of the Cal- laria had suffered relatively little from the effects of human incursion. Three small Indian villages with their adjacent plantations of bananas and yucca occupied high sections of the bank, thus creating small enclaves of secondary habitat. In addition we were informed by a missionary, who had lived a number of years in one of these villages, that some selective logging for '‘cedar” had taken place in the forests upstream during periods of high water. As “cedar” trees occur uncommonly and singly, the effects of this logging were not apparent. Thus the observations reported here, to a close approxi- mation, should reflect the status of birdlife in an undisturbed primary region. The distinctive feature of the Callaria is that natural habitats replace one another in a succession as one passes upstream. Thus, within a relatively short distance we had the opportunity to relate changes in bird distribution to an evident ecological zonation along the river. In the course of its lower 20 miles, the Callaria flows through three distinct vegetational zones. The first of these is a low-lying flood-plain or matorral formation ( MacBride, 1936 ) which extends upstream from the mouth for about 3 miles. The river runs nearly straight here and at the time of our visit was confined to a shallow channel about 100 feet in width. There was no forest within sight of the river in this stretch, the vegetation along its banks consisting of a dense growth of rangy bushes and tall grass. The second, middle zone, a transitional region, extends for 5-8 miles above the flood-plain. Along this section the river becomes gradually narrower. 273 274 THE WILSON BULLETIN S(‘i)ternl)er 1967 Vol. 79, No. 3 turns more frequently, and flows between progressively steeper banks as one ])roceeds upstream. Concommitantly, the character of the vegetation changes from that of the lower reaches to the high overhanging canopied forest typical of the upper river. In most of this transitional section the forest does not impinge on the banks but lies back somewhat. A bordering strip, up to 50 yards in width, of tall grass and or dense shrubbery and bushes fills the intervening area. In the third zone, further upstream, the forest closes in on the banks of tbe river, the channel becomes reduced to a width of 40-70 feet, and the stream flows rapidly. The overhanging trees are sufficiently tall to shade the water for much of the day. Numerous fallen trunks lying in the channel provide perches for hawks, kingfishers, swallows, and flycatchers. By early August the dry season in eastern Peru is well advanced. Conse- (juently, during our visit the river’s flow was near the minimum for the year. Extensive sandy banks were exposed along most of its course, and in the lower section particularly there were many bars and shoals in mid-stream. During the rainy season, which extends from November to May, the Ucayali and its tributaries fill with water, the annual fluctuation in river level approach- ing forty feet in many places. Although we were told that there had been no rain for more than two months, the vegetation, except for a few species of deciduous trees, showed few signs of desiccation either close to the river or on higher ground. The high humidity, heavy dew each night, and low evapo- ration from the shaded forest floor are probably all important in maintaining the verdant aspects of this region throughout the dry season. Table 1 summarizes our observations on the distribution of birds in the three vegetational zones. The relative abundance in each zone is given for 88 species of birds. Nomenclature follows that of de Schauensee ( 1966 I . Spe- cies that were regularly seen in pairs are denoted by a “p” in parentheses after the name. The only positive evidence of breeding activity that we ob- tained was a nest burrow containing a single white egg attributed to Mouasa ni^rijrons by our Indian guides. A summary of the zonal distribution of the 88 species is presented in Table 2. The species in each zone have been classified according to whether they occurred in all three zones, in two, or only in the zone in question. Those found in all three must occupy niches that all three zones share in common, for example, the air space over the river. The data in Table 2 suggest the following statements regarding the en- vironmental factors controlling bird distribution on the Rio Callaria. (1) The avifauna of the lower zone is by far the poorest in species but nevertheless is distinct to a high degree. Apart from the 11 wide-ranging forms ( two storks, one vulture, one kingfisher, one puffbird, two flycatchers. Diamond and Tert.orgh PERUVIAN BIRD DISTRIBUTION 275 Table 1 List of Bird Species Observed along the Rio Callaria. (Tlie relative aliundance of each species in the three vegetational zones is follows: +5 observations; + + , 4-10 observations; + ++, more 10 observations) indicated as than Zone Lower Middle Upper Ardeidae Pilherodius pileatus + Bii tor ides striatus + + Casmerodius albus + Tigrisoma sp. (p) + Ciconiidae Mycteria americana + + + Jabiru mycteria + + + + + Threskiornithidae Mesembrinibis cayennensis + Anhimidae Anhima cornuta (p) + + + + + Cathartidae Sarcorhamphus papa + Coragyps atratus + + + + + + + + + Cathartes aura + + + + Cathartes melambrotus + Accipitridae Elanoides forficatiis + Buteo magnirostris (p) + + + + + + Buteogallus urubitinga + Busarellus nigricollis + + + + Falconidae Daptrius ater (p) + + + + Daptrius americanus (p) + Milvago chimachima + + Falco rufigularis (p) + Cracidae Ortalis guttata + + + + Rallidae Aramides cajanea + Eurypygidae Eurypyga h el ias ( p ) + + Jacanidae Jacana jacana + + + Charadriidae Charadrius collaris + Scolopacidae Tringa flavipes + + 276 THE WILSON BULLETIN September 1967 Vol. 79, No. .3 Table 1 icont.) Zone Lower Middle Upper Trill ga so/itaria + Act it is macularia + Laridae Phaetusa simplex Sterna siiperciliaris (A)lumhidae Cola m bi gal I i n a tal pa coti Psittacidae Ara ararauna (p) Brotogeris versicolorus Am a zona sp. Cuculidae Piaya cay ana Crotophaga major (p) Crotophaga ani Strigidae Otus choliba Caprimulgidae Nyctidromus albicollis Trogonidae T logon viridis Trogon collar is Alcedinidae Ceryle torquata Chloroceryle amazona Chloroceryle americana (p) Momotidae Mo mot us momota Galhulidae Galbalcyrhynchus leucotis Galbula cyanescens Bucconidae M on asa n i gri jron s Cheiidoptera tenebrosa (p) Capitonidae Eubucco richardsoni Ramphastidae Ramphastos tucaniis Pteroglossus castanotis Pteroglossus inscriptus Picidae Melanerpes cruentatus Phloeoceastes melanoleucos + + + + + +++ +++ +++ +++ + + + + + + + + +++ +++ + + + + + + + + + + +++ +++ ++ +++ ++ + + + + + + + + + + + + + + + +++ +++ + + + + + + + + + + + + + + + Diamond and Terl.oigli PERUVIAN BIRD DISTRIBUTION 277 Table 1 [cont.) Zone Lower Middle Upper Dendrocolaptidae Xiphorhynchiis sp. Furnariidae Furnarius leucopus Formicariidae Pygiptila stellaris Cotingidae Cotinga sp. Tityra sp. Tyrannidae Colonia colonus Arundinicola leucocephula Pyrocephalus rubinus Ochthornis littoralis Tyrannus melanocho/icus (p) Pitangus sulphuratus (p) Hirundinidae Tachycineta al biventer Atticora fasciata Stelgidopteryx ruficollis Corvidae Cyanocorax violaceus Troglodytidae Thryothorus cor ay a Mimidae Donacobius atricupillus (p) Coerebidae Coereba flaveola Dacnis cay ana Dacnis lineata Thraupidae Chlorophonia cyanea Tanagra laniirostris Tangara chi/ensis Ramphocelus carbo Cissopis leveriana Icteridae Psarocolius sp. Cacicus cela Icterus icterus Agelaius icterocephalus Fringillidae Saltator coerulescens Paroaria gularis (p) + + ++ + + + + + + + ++ ++ +++ + + + ++ +++ +++ ++ ++ +++ + + + +++ +++ + + + ++ ++ + + +++ ++ + + + +++ + + +++ + + 4- + + + + + + + ++ + + + + ++ ++ ++ + ++ +++ + + + I 278 THE WILSON BULLETIN September 1967 Vol. 79, No. 3 Table 1 icont.) Zone Lower .Middle Upper Sporophita castaneiventris + + Myospiza aurifrons + Total 26 57 58 Combined Total 88 three swallow s, and one tanager ) w hose distribution was largely independent of the character of the vegetation, the lower zone was found to share rela- tive few species with the middle zone and none at all with the upper zone. It was apparent moreover that the waters of the lower Callaria are ecologi- cally distinct from those of the nearby Ucayali. The most striking evidence for this distinction was provided by the distribution of the river cormorant, Fholacrocorax olivaceus. which occurred on the Ucayali in flocks of thou- sands but was altogether absent from the Callaria. Three other common species of the Ucayali. Casmerodiiis alba, Phaetusa simplex, and Sterna superciliaris, appeared on the Callaria only in the immediate vicinity of its mouth, and there in sparing numbers. 12) As could be expected, the middle zone is faunistically the least distinct of the three. It showed the lowest proportion of characteristic species I 26 per cent ) . Thus our impression that the middle zone is a region of vegeta- tional transition between the flood plain scrub habitat and the upstream forests is confirmed by the distribution of bird species in the three regions. It will be noted in Table I that the middle zone was the only one in which all three species of kingfishers were found. Ceryle torquata, Chloroceryle amazona, and C. americana form a graduated series from large to small, respectively. The distribution of the three species was closely correlated with the width and swiftness of flow of the Callaria. Ceryle torquata was the most abundant form along the lower section, while Chloroceryle amazona was more common in the middle zone where the river is narrower and faster. The smallest kingfisher, Chloroceryle americana, was infrequent in the middle zone but was found with C. amazona in equal numbers on the sheltered and rapidly flowing water of the upper zone. (3) The upper zone, though sharing 43 per cent of its avifauna with the middle zone, nevertheless had the highest proportion ( 38 per cent I of char- acteristic species. Thus, as a natural habitat the forest can be shown to offer more opportunities for ecological specialization than the habitats in the two downstream zones. In fact, apart from the wide-ranging species found over the river the fauna of the upper zone appears to be entirely distinct from that of the lower zone. Diaiiioiiil uiul Torl.orgh PERUVIAN BIRD DISTRIBUTION 279 Zonal Distribution Table 2 OF Bird Species on THE Rio Callaria. Zonal distribution of species Lower zone Middle zone Upper zone No. of species Per cent of total No. of species Per cent of total No. of species Per cent of total Observed in all zones 11 42 11 19 11 19 Only in upper and middle — — 25 44 25 43 Only in middle and lower 6 23 6 11 — — Only in upper and lower 0 0 — — 0 0 Only in one zone 9 35 15 26 22 38 Total 26 100 57 100 58 100 (4) It is evident that overall species diversity is promoted to a much greater extent by the more complex multi-storied vegetational structure of the upper and transitional zones than by the flood-plain scrub of the lower zone. (5) The fact that the three zones shared in common only 11 species of birds suggests that ecological specialization may have played a major role in the development of the strikingly rich neotropical avifauna. Our list of 88 bird species undoubtedly represents no more than 30 per cent of the total number that occur in the vicinity of the Rio Callaria. However, our observation time was fairly evenly divided among the three zones, and there are no outstanding reasons for supposing that any of the faunal samples we obtained are not representative. Thus it seems safe to assume that a more thorough-going study would only strengthen our conclusions, though at the quantitative level alteration of the results would be expected. FEEDING ASSEMBLAGES While on the Callaria we located two fruiting trees in which large and heterogeneous groups of birds had assembled for the purpose of feeding. The birds using each of these trees were observed for several periods of 1-2 hours. The first tree (see Table 3 for list of bird species observed in it) was located about 100 yards from the Rio Callaria in second growth near an Indian village and bore many brown plum-sized fruits. The second tree (see Table 4 for species list) overhung the Rio Callaria from the edge of tall upper-zone forest, and was heavily laden with orange cherry-sized fruits. A striking fact evident from the tables is that these two feeding trees contained no species in common. The first tree (Table 3) had a broad crown about 40 feet high and stood in dense second growth in the transitional zone near an Indian village. A much taller primary forest was less than 100 yards away, however. The second tree (Table 4) was located on the river hank in the primary forest upstream and was more than twice as tall as the first. 280 THE WILSON BULLETIN SojitPiiiber 19()7 \ ol. 7'). No. 3 Table List of Birds ()bseiut:i) in 3 First Fruiting Tree. Ihotogeris versicoloriis Goereha jiaveola l^iaya cay ana Psarocolius sp. G a! ha! cyrh yn ch as leu cot is Gacicus cel a Melanerpes cruentatus Icterus icterus Demlrocolaptidae sp. Tityra sp. S poroph ila cast an ei ventris A second fact apparent from the tables is the large number of families represented in both feeding assemblages. The 11 species found in the first tree represent nine families, while the 17 from the second tree include 10 families. Similarly, Land ( 1963 > recorded members of 11 families of birds taking fruit from a tree in Guatemala. The association of diverse species possessing a wide variety of sizes and bill shapes in feeding trees suggests extensive niche overlap among carpophagous birds in the neotropical forests. It is evident that birds so conspicuously different from one another as cha- chalacas, parrots, toucans, and honeycreepers at least occasionally utilize the same food sources. Though tropical species are usually assumed to be more specialized and less versatile than their counterparts in higher latitudes ( Klopfer, 1962; Margalef, 1963), the congregation of large numbers of disparate species at ephemeral food sources suggests that many of them may have rather flexible feeding habits. In observing the second tree (Table 4), we noticed that the individuals of certain species were distributed in a non-random fashion. Trogons \Trog,on collaris and T. viridis ) kept to the lower branches, while the toucan. Ram- phastos tiicanus. the honeycreeper, Dacnis cayana. and the tanager, Tangara chilensis. were seen only in the upper branches. Other species, e.g., the chachalaca, Ortalis guttata, and the Ptero^Iossus toucans, appeared to feed indiscriminately in the lower, middle, and upper branches of the crown. As MacArthur (1958) has so carefully shown for 5 species of Dendroica war- blers in a Maine spruce forest, interspecific competition for food is greatly reduced in species having pronounced preferences for different locations in the canopy. In general, birds arrived at and left both fruiting trees as individuals or else as groups of several individuals belonging to one species. The majority of species was seen to come and go in this manner. Although the species composition of these assemblages changed gradually with time, the total number of birds in a given tree did not vary by more than a factor of two during the observation periods. The largest movements were the arrivals and departures of small groups of parrots or toucans. Thus the congregation Diamotul and Tcrl)orf;li PERUVIAN BIRD DISTRIBUTION 281 Table 4 List of Birds Observed in Second Fruiting Tree. Orta/is guttata Phloeoceastes melanoleucos Amazona sp. Cotinga may nan a Trogon co/laris Cotinga cayana Trogon. viridis Cyanocorax violaceus Capita sp. Dacnis lineata Ramphastos tucanus Dacnis cayana Pteroglossus castauotis T an gar a ch il ensis Rteroglossus inscriptus Ramphocelus car bo Cissopis leveriana of birds that are attracted to fruit trees for feeding cannot be regarded as flocks in that they do not appear to have any social or temporal integrity. Rather, they may be considered as transient and more or less chance as- semblages of small flocks of several species plus scattered individuals of others. Socially organized itinerant feeding flocks of the kind extensively described by Davis (1916), Short (1961), and Moynihan (1962) are of widespread and common occurrence in neotropical forests. Such true flocks differ from feeding assemblages in the following respects. ( 1 ) They are characterized by interspecific social interactions rather than by the lack of them. ( 2 ) They retain their integrity as social units while progressing through the forest. Feeding assemblages of necessity are stationary. (3) Members of a feeding flock pursue a variety of food sources, both plant and animal, while in a feeding assemblage all individuals are consuming the same food. It can be expected that members of feeding flocks may temporarily join feeding assemblages and that birds initially in feeding assemblages in turn may leave to join feeding flocks. Such exchanges could have taken place in the second feeding tree during our observations, as birds of the genera Daciiis and Tangara are known (Moynihan, 1962) to join feeding flocks. SUMMARY 1. The distribution of liirdlife along a 20-30 mile section of the Rio Callaria (De- partment of Loreto, Peru) has been tabulated with reference to three conspicuously distinct ecological zones, through which one passes in succession when travelling up- stream from the mouth. They are characterized by differences in the width and rate of flow of the stream and by the principal features of the vegetation on the hanks. The ecological character of the zones has been analyzed by considering the proportions of the fauna of each which occurred in only that zone and in the two other zones. The degree of faunal distinctness and the pattern of faunal overlap with other zones was different for each zone. As expected, greater species diversity was found in the zones of greater vegetational complexity. 282 TIIK WILSON nULLLTIN Sciitemhci- 1907 Vol. 79, Ni). 3 2. 1'wo fruiting trees wliieli w(‘re lieing used for feeding by representatives of nine and ten bird families, respectively, have lieen described. The significance of the high diversity of bird sj)ecies using these fe(“ding trees has he<*n discussed. Acconij)anying hehavioral ohservations liave been considered in relation to the problem of interspecific competition. Assemblages of birds using sucli feeding trees have been operationally distinguished, on the basis of three behavioral criteria, from the itinerant feeding flocks, so jirevahmt in neotropical forests, that recently have received much attention from other authors. ACKNOWLEDGMENT We are greatly indebted to Dr. Maria Koepcke of the Museo de Historia Natural in Lima for aid in identifying from our field notes many of the species listed in this report and to Dr. K. A. Paynter, Jr. for (omments on the manuscript. The identific-ations of all species cited here have been checked against specimens in the Museo de Historia Natural in Lima, the Museum of Comparative Zoology of Harvard University, and the American Museum of Natural History. LITERATURE CITED Davis, D. E. 1946 A seasonal analysis of mixed flocks of birds in Brazil. Ecology, 27:168-181. DE SciIAUENSEE, R. M. 1966 The species of birds of South America and their distribution. Acad. Nat. Sci., Philadelphia, Pennsylvania. Kloi’Fek, P. H. 1962 Behavioral aspects of ecology. Prentice-Hall, Inc., Englewood Cliffs, N. J. Land, H. C. 1963 A tropical feeding tree. Wilson Bull., 75:199-200. MacAhthuh, R. H. 1958 Population ecology of some warhlers of northeastern coniferous forests. Ecology, 39:599-619. MacBhide, J. E. 1936 Elora of Peru. PuhL Field Mas. Nat. Hist., Bot. Ser., 13, Part I, No. 1. Mahgalef, R. 1963 On certain unifying principles in ecology. Amer. Nat., 97:357-374. Moynihan, M. 1962 The organization and probable evolution of some mixed species flocks of neotropical birds. Sj?iithsonian Misc. PuhL, 143:1-140. Short, L. L., Jr. 1961 Interspecies flocking of birds of montane forest in Oaxaca, Mexico. Wilson Bull., 73:341-347. DEPARTMENT OF PHYSIOLOGY, UNIVERSITY OF CALIFORNIA MEDICAL CENTER, LOS ANGELES, CALIFORNIA (.J.M.D. ), AND DEPARTMENT OF BOTANY, UNIVERSITY OF MARYLAND, COLLEGE PARK, MARYLAND ( J.W.T. I , 13 JUNE 1966. REPRODUCTIVE SUCCESS OF RED-WINGED BLACKBIRDS IN NORTH CENTRAL OKLAHOMA Stephen V. Goddard and Veryl V. Board The general upward trend in the number of Red-winged Blackbirds {Agelaius phoeniceus ) nesting in Oklahoma can probably be attributed to the large number of farm ponds, flood detention, and flood control dams which have beeen constructed in the last 23 years. During this period an estimated 161,000 farm ponds, flood detention, and flood control dams have been built in Oklahoma, and an additional 1,500 are being constructed every year ( Anon, 1963 ) . Presently, there are more than 4,500 farm ponds and flood control structures in the two north-central counties (Payne and Noble) selected for this study. Many of these do not have good redwing nesting habitat. However, ponds with good growths of cattails { Typha sp. ) have high densities of nesting birds. The major objectives of this study were to examine the phenology of red- wing nesting and to determine their reproductive success in these new habitat situations. The effect on reproductive success of early versus late nesting, type of nesting cover, height of the nest above the surface of the ground or water, and water depth below the nest were considered. METHODS AND GENERAL DESCRIPTION OF AREAS Observations were conducted throughout the breeding season on ten study areas selected on eight ponds and two lakes. Only the larger nesting colonies were studied on the two lakes (Boomer and Yost). Nests were numbered using a “Sanford’s Marker Compact.” The number was written on two or three stems or limbs supporting the nest. Blue was found to be the best color and remained readily visible for two or three weeks, at which time the nest could be re-marked, if necessary. Initially, the following data were recorded: date, area, general weather conditions, time, number of redwings and nests in the area, and type of nesting vegetation. The height of the nest above the surface and the water depth were measured. The number of eggs and/or young were noted when present, and the ages of the nestlings were recorded. The nestlings were aged by the criteria used by Allen (1914). The subse- quent history of each nest was recorded during a series of visits. The number of active nests, those which contained at least one egg and which subse- quent observations indicated were not abandoned, was used to determine the number of females using an area. This was necessary because usually fewer females than active nests were observed around a pond. Occasionally, more females were observed than there were active nests and in these cases, the actual number of females observed was used as a measure of the female population size. The study areas varied in size from 0.2.5 to 7.3 acres (Table 1). 4'he cattails growing around the borders of the ponds varied in stand density and area of cov('ragc. All of 283 284 THE WILSON BULLETIN S<‘|.lcnil)cr 1%7 V(.l. 7<), No. 3 Table 1 Size, Cattail Nesting Covek, AND TeHIUTOHIAL Males Area Area ( acres ) Cattails ( acres ) Average number territorial males Pond 9 0.60 0.03 3 Pond 30 0.60 0.08 2 Pond 51 0.25 0.12 2 Pond 52 1.00 0.90 7 Pond 53 0.40 0.10 5 Pond 63 0.50 0.08 4 Ihnid 64 0.30 0.15 5 Pond 66 0.25 0.25 3 Boomer Lake 4.50 1.00 9 Yost Lake 7.30 1.65 10 Total 15.70 4.36 50 the ponds, except Pond 53, had tall perches available on or adjacent to the pond. Male redwings used the tallest cattails and nearby fence posts for song perches in this area. RESULTS The average amount of cattails available per male varied from 0.01 acres (435 square feet) on Pond 9, which had the smallest amount of nesting cover, to 0.165 acres per male (7,187 square feet) on Yost Lake, which had the largest block of nesting cover (Table 1). A few males already had established territories when the observations were first initiated on 8 April. Their number reached a peak during early May and then slowly declined. One male was still on territory on 29 July. How- ever, it was not in the area on 31 July when observations were terminated. The nesting cycle sequence continues with the arrival of the resident fe- males and pairing behavior. Nero ( 1956 ) reported that the first female arrived at a nesting colony on a marsh in Wisconsin on 8 April. He also indicated that pair formation begins or actually occurs when a female enters a male’s territory. Meanley and Webb ( 1963 ) stated “females usually move into territories and begin pairing after April 1 in Maryland.” By the middle of April in New York, most of the females were paired (Case and Hewitt, 1963 ) . Small flocks of female redwings were observed at various times on the study areas throughout April, which indicated that all females were not paired. There were four known pairs on the study areas by 17 April. The tendency of male redwings to pair with more than one female has been reported by many authors: Wright (1907), Allen (1914), Linsdale ( 1938 ) , Nero ( 1956 ) , Case and Hewitt ( 1963 ) , and Meanley and Webb ( 1963 ) . Similarly, redwings were found to be polygynous in this study. (Mxlilanl arid Boai (I REPRODUCTIVE SUCCESS OE REDWINGS 285 Table 2 Number OF Nests, Active Nests, Eggs Laid, Clutch Size, Eggs Hatched, Young Fledged, and Per Cent Successful Nests for THE Ten Study Areas Number Active Esgs Clutch Ekss Youns Per cent suc- Area of nests nests laid size hatched fled5^ed cessfid nests Pond 9 9 9 28 3.1 8 5 22.2 Pond 30 8 7 23 3.3 1 0 0.0 Pond 51 13 7 25 3.6 10 6 28.6 Pond 52 79 61 207 3.4 71 29 14.8 Pond 53 47 44 153 3.5 68 50 38.6 Pond 63 29 26 92 3.6 42 22 26.9 Pond 64 30 29 105 3.6 69 50 58.6 Pond 66 6 5 19 3.8 14 7 60.0 Boomer Lake 23 15 45 3.0 4 4 6.7 Yost Lake 62 40 124 3.1 42 23 17.5 Total 306 243 821 3.4 329 196 26.7 There were only 0.68 females per male early in the nesting season. This ratio increased to 1.95 by the peak period of nesting, which was in the third week of May. The sex ratio declined homewhat during the next three weeks and then increased to 2.19 during early July, when several females were renesting or attempting to raise a second brood. The average sex ratio for the period from 16 April to the end of July was 1.57 females per male. The first nest, which contained two eggs, was located on 22 April. This coincides with the findings of Allen (1914 ) and Meanley and Webb (1963). Beer and Tibbits (1950) recorded their earliest nests on 25 April and 1 May in their two-year study in Wisconsin. Some females built several nests before starting a clutch. This is illustrated by the fact that although 306 nests were fully completed and lined, only 243 of them were known to have been actively used by the female (Table 2). Early in the breeding season, female redwings appeared to be intolerant of disturbance and readily abandoned their nests. The rate of desertion was low (1.2 per cent) once the female had initiated a clutch or if nestlings were present. Redwings were persistent renesters. Some females on ponds with high predator populations initiated nest after nest only to have them broken up. Generally, females will build a new nest when renesting or attempting a second brood. However, there were five instances where a female laid eggs in a nest in which the original clutch had been destroyed. This was observed early in the nesting season and only occurred once on any pond. No nest was used more than twice. Only one of the five nests mentioned above was successful. 286 THE WILSON RULLEIIN September 1967 Vol. 79, No. 3 Table 3 CoMi*AHis()N OF Numbkh, Clutcii Size, Young Fledged, and Nesting Success BETWEEN EaBLY AND LaTE NeSTS Time of Active Clutch Young Successfid Per cent suc- nesting nests size fledged nests cessful nests Before June 1 155 3.6 135 45 29.0 After June 1 88 3.2 61 20 22.7 There were 821 eggs laid in the active nests for an average clutch size of 3.4. The range was from one to five eggs with four being the most common number. Allen 1 1914 ) reported that incubation began after the third egg and usually 11 days were required for the eggs to hatch. Using this information, incubation time determined during the present study varied from 10-13 days. Three hundred and twenty-nine of the 821 eggs hatched, giving a hatching success of 38.9 per cent. One hundred and ninety-six young were fledged or 23.9 per cent of the total eggs resulted in fledged young. The results of many studies, Perkins (1928), Wood (1928), Wood (1938), Smith (1943), Beer and Tibbits (1950), and Williams (1960) have indicated that young were fledged from 48 per cent or more of the eggs. Nesting success is another measure of reproductive success. A successful nest was one that fledged one or more young. Young fledged from 65 of the 243 active nests, which gave a nesting success of 26.7 per cent. This success was considerably lower than the 42 per cent reported by Wood Nesting Success in Table 4 Relation to Kind of Cover Nesting cover Active nests Number Per cent Nesting success Old Cattails iTypha) 52 21.4 38.5 Old and new Cattails 83 34.2 19.3 New Cattails 89 36.6 29.2 Willows (Salix) 10 4.1 10.0 Dogwood iCornus) 2 0.8 0.0 Buckbrush ( Symphoncarpus) 2 0.8 50.0 Bulrush (Scirpus) 2 0.8 50.0 Lead Plant ( Amorpha) 2 0.8 0.0 Buttonbusli ( Ceph (dan thus) 1 0.4 0.0 Total 243 99.9 26.7 (Mul.lanI an.l Board REPRODUCTIVE SUCCESS OF REDWINGS 287 Table 5 Nesting Success in Relation TO Nest Height above Surface OF Ground or Water Nest height ( inches ) Active nests Nunil)er Per cent Nesting success 0-12 34 14.0 38.2 13-24 125 51.4 27.2 25-36 53 21.8 22.6 Over 36 31 12.8 19.4 Total 243 100.0 26.7 (193o ) and the 57 per cent obtained by Meanley and Webb (1963). How- ever, Young (1963), in a two-year study in Wisconsin, obtained a nesting success of 35 and 24 per cent for 1959 and 1960 respectively. The major losses of eggs and nestlings were due to egg and young removal, probably as a result of nest predation in most cases, and to nests tipping over and the eggs or young falling out. Of 243 active nests, eggs were removed from 105, young from 25; 36 nests containing eggs and eight nests containing young were destroyed when the vegetation or wind tipped the nest. Three nests were abandoned and one was lost to flooding. Similarly, Smith (1943) and Beer and Tibbitts (1950) obtained results indicating that there was a greater loss of eggs than of nestlings. However, Peterson and Young (1950) for Common Crackles {Quiscalus quiscula) ^ and Young (1963 ) for Red-winged and Yellow-headed blackbirds { Xauthocepha- lus xanthocephalus) found that losses of nestlings exceeded those of eggs. In Oklahoma, early nests tended to be more successful than nests started after 1 June (late nests). This date was used as a separation criterion be- cause it fell at the end of the first nesting period and before the initiation of most renesting. On nine of the ten ponds, early nests were more successful. The one exception, Pond 64, had a nesting success of 50 per cent for early nests compared to 85.7 per cent for late nests. Overall nesting success for early nests was 29.0 per cent compared to 22.7 per cent for late nests (Table Table 6 Nesting Success in Relation to Water Depth Water depth ( inches ) Active nests Number Per cent Nesting success 0-10 155 63.8 23.2 11-20 65 26.7 29.2 Over 20 23 9.5 43.5 Total 243 100.0 26.7 288 THE WILSON BULLETIN S<‘|>ternl)er 1967 Vol. 79, No. .3 3). Nesting success among the study areas varied from zero to 62.5 per cent for early nests and from zero to o5.7 per cent for late nests. Lor the entire nesting season, nesting success varied among areas from zero to 60 ])er cent. 3 he average clutch size was larger for early nests (3.6 eggs) than for late nests ( 3.2 eggs ) . 1 here were 0.o7 young fledged per early nest compared to 0.69 young per nest for the later nests, another indication that early nests tended to he more productive. The number of nests found in each type of nesting cover is presented in Table 4. The percentage of the total nests and active nests was independent of the type of supporting vegetation. Lor vegetation types containing at least 10 nests, nesting success was highest (38.5 per cent I in old cattails. This higher nesting success may have been due to old cattails being virtually the only nesting cover available early in the nesting season when nesting efforts were more successful. A summary of the nest height above the surface of each pond is presented in Table 5. Ihe highest nesting success (38.2 per cent) occurred among nests in lower situations. Nesting success decreased as the height of the nest increased. This decrease may be attributed to a majority of the nests’ being constructed in cattails; the higher the nest the greater became the possibility of its tipping over and losing the contents. rhe number of nests constructed above each of the three water depth cate- gories is presented in Table 6. Nesting success increased directly with the depth of the water. SUMMARY During the 1965 breeding season the reproduetive suecess of Red-winged Blackl)irds was studied on eight ponds and two small lakes loeated in two north-eentral Oklahoma eounties. A few males were already on territory when observations were initiated on 8 April. Density of males on the study areas generally varied inversely with the size of the cat- tail nesting cover. Four females were known to he paired by 17 April. The nesting peak occurred during the third week of May. Cattails furnished sites for over 90 per cent of the nests. Generally, redwings built a new nest when they attempted to renest. However, on five occasions, a nest was used for two nesting attempts. This occurred early in the nesting season and only once on any pond. Eight hundred and twenty-one eggs were laid in 243 active nests for an average clutch size of 3.4. Hatching success was 38.9 and young were fledged from 24 per cent of the eggs. Sixty-five nests fledged one or more young, giving a nesting success of 26.7 per cent. Egg or young removal and nests tipping over were the major reasons for nest failure. Egg loss exceeded mortality of the young. The high nest densities in a limited area would make it possible for a single factor to destroy a large number of nests. Nesting success was higher for nests initiated prior to 1 June. Average clutch size (;...l.h.nl and Hoard REPKODUCTIVE SUCCESS OE REDWINGS 289 was greater in early nests. Nests in old cattails were more successful. Over 50 per cent of the nests were constructed less than two feet above the ground or water. Nesting success was higher for nests in lower situations and decreased as nest height increased. Approximately two-thirds of the nests were constructed above ground or aho\e water that was less than 10 inches deep. Nesting success was greater as the depth of the water below the nest increased. LITERATURE CITED Alt.kn, a. a. 1914 The Red-winged Blackbird: A study in the ecology of a cat-tail marsh. /''roc. Linnean Soc. New York, 24-25:43-128. Anonymous 1963 This is Oklahoma. Daily Oklahoman, p. 1-24. 20 October. Bkek, .1. R., AND D. Tihhitts 1950 Nesting behavior of the Red-winged Blackbird. Flicker, 22:61-77. Case, N. A., and 0. H. Hewitt 1963 Nesting and productivity of the Red-winged Blackbird in relation to habitat. Living Bird, 2:7-20. Linsdale, J. M. 1938 Environmental responses of vertebrates in the Great Basin. Amer. Midland Nat., 19:1-206. Meanley, B., and J. S. Webb 1963 Nesting ecology and reproductive rate of the Red-winged Blackbird in tidal marshes of the upper Chesapeake Bay region. Chesapeake Sci., 4:90 100. Nero, R. W. 1956 A behavior study of the Red-winged Blackbird. 1. Mating and nesting ac- tivities. WAIson Bull., 68:4-37. Perkins, S. E., Ill 1928 City park nests of Red-winged Blackbirds. Bird Lore, 30:393-394. Peterson, A., and H. Young 1950 A nesting study of the Bronzed Crackle. Auk, 67:466-476. Smith, H. M. 1943 Size of lireeding populations in relation to egglaying and reproductive success in the eastern red-wing. (Agelaius phoeniceus) . Ecology, 24:183-207. Williams, J. F. 1940 The sex ratio in nestling eastern red-wings. Wilson Bull., 52:267-277. Wood, H. B. 1938 Nesting of Red-winged Blackbirds. Wilson Bulk, 50:143-144. Wood, M. 1928 Mortality of young Red-winged Blackbirds. Bird Lore, 30:262. Wright, M. O. 1907 The Red-winged Blackbird. Bird Lore, 9:93-96. Young, H. 1963 Age-specific mortality in the eggs and nestlings of blackbirds. Auk, 80: 145-155. DEPARTMENT OF ZOOLOGY, OKLAHOMA STATE UNIVERSITY, STILLWATER, OKLA- HOMA. (PRESENT ADDRESSES: DEPARTMENT OF BIOLOGY, WISCONSIN STATE UNIVERSITY, RIVER FALLS, WIS., AND DEPARTMENT OF BIOLOGY, ARKANSAS COLLEGE, BATESVILLE, ARK.), 7 MARCH 1966. BEHAVIORAL STEREOTYPY IN BIRDS Peter H. Klopfer IT has previously been argued that the climatic stability provided by the tropics allows animals to specialize to an extent not possible where cli- matic conditions and the sources of food and other necessities change season- ally, if not daily (see Klopfer, 1962 for bibliography). This permits the coexistence of more species than would be true in a population of “jacks-of- all-trades,” and partially explains the greater faunal diversity of the tropics as compared with temperate zones. I have sought to put this notion to an experimental test by comparing the degree of behavioral stereotypy (which is, in effect, a measure of niche size: the larger the niche the less stereotyped the animal ) in selected representa- tives from the temperate and tropical avifaunas. The demonstration of stereotypy, of course, does not necessarily prove that constancy of available sources of energy explains species diversity. Greater stereotypy in tropical forms would provide collateral evidence for the constancy-diversity relation- ship, however. Specifically, I have sought to measure degrees of stereotypy in foliage preference and motor pattern of individuals of several species of birds. (The ultimate aim, it should be added, is to include several dozen species, repre- senting many families, in this survey, and to include measures other than foliage preferences and movement patterns.) Regarding the relevance of measures of foliage preference, consider the work of MacArthur, MacArthur, and Freer (1963) who studied early serai stages in North America. They predicted the bird species diversity as well as the actual species which would he present in a given area from measure- ments of diversity in foliage height density. They showed that each bird species occurred in habitats with a characteristic proportion of foliage in each of three arbitrarily designated layers. These preferences can reasonably he assumed to be based upon either leaf number, leaf size, or leaf shape, or some correlate of these variables, since they alone determine foliage density. Thus, the work of MacArthur, et al. justifies the use of leaf shape and size as the principal discriminanda in studying perceptual preferences. Of course, there are bird species for whom some other and very particular element of the environment such as an unique nest site or particular food will be more important than the characteristics of the foliage density. In most instances these exceptions can be noted. Nor does the importance of foliage char- acteristics mean that other components of the environment are irrelevant. However, we can at least assert that foliage characters are an important factor in habitat selection. 290 IVUM H. k lopfer BEHAVIORAL STEROTYPY IN BIRDS 291 Other factors than constancy of energy source may influence the degree of stereotypy. Most conspicuous among these is the role of competition, e.g., the numher of potentially competing species. On islands or other geograph- ically or topographically isolated areas the species diversity may he well helow that of comparable areas of large continental land-masses ( see Mac- Arthur, 1965). In the absence of competitors, the ecology of many species is known to change (Crowell, in press, and see van Valen, 1965) generally in the direction of increased plasticity (van Valen, 1965). This increased plasticity may have two different manifestations: each individual of the species concerned may become more plastic, i.e., do more different things, or, the individuals may remain as stereotyped as ever, hut with different individuals specializing for different ways of life, or a combination. This would represent decreased specific ( as opposed to individual ) stereotypy, and might well be regarded as a first stage in the formation of subspecies. It is as interesting to assess the interaction between degree of isolation ( or competition) and climatic stability as to study the latter alone. Thus, our design calls for comparisons between insular and continental birds of the tropics and temperate regions, as diagrammed below: Islands vs Continents temperate Bermuda Eastern U.S. vs tropical West Indies Panama DEFINITIONS AND METHODS “Behavioral stereotypy” refers both to perceptual and motor stereotypy. On the perceptual side, the stereotypy involves a sensitivity to, or an aware- ness of, or preference for, a limited range of a larger complex of stimuli. An animal that responds only to a narrow band of wavelengths, for instance, would be considered perceptually more stereotyped than one responding to a wider band. On the motor side, stereotypy refers to the availability of only a small variety of movements by means of which an animal can accomplish a given act. It reflects an inability to adjust movements in accordance with changes in the form of the substrate. In either instance, the constraints may be peripheral (in terms of muscle attachments or shapes, or sensory filters), or due to central nervous mechanisms. While it is of interest to study the nature of the constraints and to determine whether they differ systematically, this is not considered here. To measure stereotypy in preferences for particular types of foliage the birds were tested in rooms divided by netting into two chambers, alike ex- cept for the foliage with which they were decorated. This foliage was made of a green plastic and consisted of one of I kinds of “leaves” that differed 292 THE WILSON BULLETIN S('|itcml)ei- 1967 Vol. 79, No. 3 Fig. 1. IMiotooraph of artificial leaves. in size or shape or density ( a large and small ”Oak“ and “Elm’* type I ( Fig. 1 I . Movement of the bird from one chamber to the other, and thus the time spent in each chamber, was monitored by a series of photo-cells in the sole connecting passage between the two chambers, which also served as a feeding place. The three test rooms averaged 3 by 3 by 4 meters. Details of the procedure and controls for position preferences have previously been pub- lished ( Klopfer, 1965 i . The four foliage types employed were offered in all possible pairs, though because of escapes or mortality, every bird was not tested with every pair. For each pair of foliage types, the portion of time spent amidst one or the other was calculated and converted to a discrimination index, H. The rationale for the use of the index has been summarized as follows ( Klopfer, 1965 ) : the more stereotyped the preferences of an organism, the more marked will be its preferences among an array of discriminanda. If the discriminanda are paired, a non-stereotyped or plastic individual should select each member of each pair. 50 per cent of that time. A highly stereo- typed individual will tend to select one member of many pairs to the exclusion of the other. The greater the stereotypy the higher the proportion of pairs BEHAVIORAL STEROTYPY IN BIRDS 293 i>. K <-f H. .|.[cr Table 1 Species Rearing conditions 11 of individual birds (11 values are means for tests with 4 pairs of foliage; H are the means of the individual H values) Panamanian tanagers Hand-reared: (Thraupis cana. without sight of foliage 0.06, 0.08, 0.09, 0.14, 0.28 (H = 0.13) and Ramphocelus Hand-reared : (Umidiatus ) with pine needles 0.08, 0.12, 0.28, 0.31 (H = 0.20) Wild-trapped : 0.16,0.17, 0.19, 0.19, 0.20 0.20, 0.21, 0.25, 0.25, 0.28 0.30, 0.32, 0.36 (Tl=: 0.24) Dominican Rananaquits ( Coereba flaveola ) Wild-trapped : 0.12, 0.12, 0.18,0.21,0.27,0.31 (H = 0.20) for which the choice should deviate from 50 per cent. The stereotypy index, //, represents the proportion of choices that deviates from 50 per cent. Of course, if a bird selects its habitat using one clue only, for instance light intensity, it would in fact be stereotyped but not so labelled on the basis of tests with irrelevant discriminanda. Thus far, the extremes of H values recorded have been 0 and 0.8 ( see below ) . Motor stereotypy was assessed in two different ways. First, by slow motion analysis of movie film of foraging movements of birds in their natural habi- tat, taken at varying times throughout the day. Secondly, by observation of the movements of captive birds on artificial “trees.” These “trees,” ca. 2 m high and varying from ca. % m to 2 m in diameter from top to bottom, were constructed of 0.5 cm steel reinforcement rods so as to allow the bird to fly in either a radial, vertical, or horizontal direction without hindrance. ( By radial flight is meant flight along a branch, by vertical movement, across branches and in the vertical plane, and similarly, across the horizontal plane for horizontal or oblique flight. ) Thus, the environmental constraints upon certain kinds of flight that are posed, for instance, by the thick horizontal strata of foliage or an absence of horizontal branches on some large cacti, were eliminated. The degree of motor plasticity of the subjects could be assessed (even though arbitrarily) under conditions where all three com- ponents of the normal flight directions of birds were equally possible. A stereotyped individual, then, would he one which failed to adapt its pattern of flight to this relative absence of physical constraints. Scoring was achieved by simply calculating the proportion of time spent flying in one or other of these planes. The laboratory and some of the field data were obtained from three tro])i- cal species. Blue and Crimsoii-hacked tanagers (Thraupis cana and Rampho- 294 THE \MLSO\ BULLETLN Septemlier 1967 Vol. 79, No. 3 Fig. 2. Habitats in Puerto Rico in Avhich Bananaiiuits are among tlie three most common species (after MacArthur). celus dimidiatus\. and the Bananaquit \Coereba flaveola). Some of these birds were wild-trapped as adults, others were hand-reared, either without sight of foliage or with a particular kind of foliage. ( Comparable data have been previously published for groups of hand-reared and wild-trapped Chipping Sparrows iSpizella passerina) and others, Klopfer, 1962, 1965.) The Bermuda field data are taken from the work of Crowell (1962) on the feeding and behavior of Cardinals \ Richmondena cardinalis ) and Catbirds ( Dumetella carolinensis) and vireos ^Vireo griseus) . The inadequacy of the sampling and our frequent inability to apply statis- tical measures of significance, will be apparent. It is the result of the exces- sive amount of time required for hand-rearing birds from an early age to maturity. The justification for presenting such incomplete data lies (1) in the importance of the general problem and (2) in the desire that this ap- proach may become known to and explored by others. DATA AND CONCLUSIONS Perceptual preferences of tropical mainland (Panama) species. — The data of Table 1 suggest that these tropical birds are not innately stereotyped. If reared for the first 8 weeks of life in a particular type of foliage they become more stereotyped. Wild-trapped adults are yet more stereotyped. Of the hand-reared birds, only three out of nine of the tanagers showed scores overlapping with those of any of the 13 wild-trapped tanagers. 51ost of the hand-reared birds had scores very much below those of the wild birds (i.e., they were less discriminating in their foliage choices ) . BEHAVIORAL STEROTYPY IN BIRDS 295 IVtcr H. K lopfer I007o-| o A X A 507o- RADIAL above limb o = University Park • = La Paquera °= Mangrove Swamps ■ = Casuarina Groves g A J JL below limb A X ■ _Q HORIZONTAL A= Coconut Palms A= Maricao x= El Yunque • ° Q VERTICAL Fig. 3. Movement stereotypy of Puerto Riean Bananaquits. Perceptual preferences of tropical island (West Indies) species. — Eigure 2 indicates the character of the habitats of Puerto Rico in which Bananaquits are among the three commonest birds (the data for this figure were gener- ously provided by R. H. MacArthur ) . Erom the variety of habitats in which they occur, it will be apparent that, if Bananaquits can in any way be considered “stereotyped,” this is not manifested by their restricting them- selves to any particular plant formation. Is it possible that they are re- sponding to some feature common to all of the habitats in whieh they are found, and lacking in those habitats where Bananaquits do not occur? Table 1, which provides the data from foliage preference experiments with Do- miniean, wild-trapped Bananaquits (on Dominica, Bananaquits are also found at all altitudes and in most habitats, as on Puerto Rico) shows a rather low discrimination index (ranging from 0.12 to 0.31). Particular leaf shapes or sizes are apparently no more rigidly preferred than is the case with the relatively “plastic” hand-reared isolates of the other species tested, whether from tropical or temperate zones. In an experiment where the ehoice was between two different densities of the same foliage (artificial bamboo), a similarly low index obtained (0, 0.03, 0.1 I, 0.30, and 0.3<3 1 . indicating that leaf density, per se, was not by itself important for three out of the five birds. Another experiment in which the Bananaijuits could choose 296 THE WILSON BULLETIN Septcmher 1967 Voi. 79, No. 1007o-i 507o- RADIAL HORIZONTAL VERTICAL above limb below limb Fig. 4. Movement stereotypy of Panamanian Ijananaciuits. between articial bamboo and squares of cardboard, arranged so as to afford a similar range of light intensities and “hiding places” yielded scores of 0.06, O.Oo, 0.16, 0.71, 0.71, and 0.80. Thus, for half of the individuals, the pres- ence of leaves was clearly important (scores of 0.71, 0.71, and 0.80) though strong preferences for any given configuration were, as indicated earlier, not evident. Comparable data for Bananaquits from the mainland are not available, though we should note our impression that, in Panama, Banana- (juits are far less ubiquitous than they are in the West Indies. In Panama they appear to be restricted to the forest edge and home gardens. MacArthur (1965) has also suggested this in pointing to the increased “between-habitat” differences on the mainland as compared with nearby islands. Motor patterns of tropical mainland and island species. — Figures 3 and T indicate variations in motor patterns of the Puerto Rican and Panamanian Bananaquits. Despite the variety of habitats in which the former is found, the similarity in its patterning of movements within all these habitats is strik- ing. The timing of movements, however, is less stereotyped, as is seen in Figures 5 and 6, in which are graphed the duration of feeding bouts in dif- ferent habitats. ( By “feeding bout” is meant the period from one flight to the next, during which period feeding occurs more or less continuously. ) IVter H. Klui-fer BEHAVIORAL STEROTYPY IN BIRDS 297 University Park La Paquera Mangrove Swamps • •• • • • • • • • • Casuarina Groves :<:••• ••• Coconut Palms Maricao ••• ••-v./.v: * • El Yunque 0 100 200 300 400 500 600 Fig. 5. Duration of feeding l)outs of Puerto Rican Bananaquits. There are some significant inter-habitat variations in this measure ( spe- cifically, Maricao vs. La Paguera, Median test, Tate and Clelland, 1957), presumably reflecting differences in the kind and amount of food available. Thus, these birds do make certain adjustments to the nature of their habitat. The data for the mainland Bananaquit show a basically similarity to Banana- quits at Maricao, P. R., both with regard to movements and duration of feeding bouts. The Maricao habitat appears, at least superficially, the most similar of any of those on Puerto Rico to the Bananacjuit habitat in Panama. On the artificial trees, neither wild-trapped Bananaquits (Dominica) or Blue Tanagers ( Panama ) adhered to the pattern of movements characteristic in nature. Radial movements were virtually nonexistent; Bananaquits’ move- ments were principally in the horizontal plane ( 68 per cent ) ; those of the tanagers almost evenly divided between horizontal and vertical (54-16 per 298 THE WILSON BULLETIN .S<‘pt<*nil)cr 1967 Vol. 79, No. 3 Bananaquits • ••••• /•• • • ••«•••••• • •• •• •• • •• •• •••• •• •• • • • Blue Tanagers ...... ... . . . . • 0 100 200 300 400 500 600 700 Fig. 6. Duration of feeding bouts of Panamanian liirds. cent). This does not support the notion that these birds are incapable of modifying the pattern of their movements. Motor patterns of temperate mainland and island species. — Ligure 7, taken from Crowell, illustrates in a somewhat different manner, the feeding methods of three species of passerines common both to the eastern U.S. and the island of Bermuda. The differences between island and mainland populations were significant ( Chi square, P < 0.001 ) . Mainland Cardinals and Catbirds showed a greater diversity of feeding methods than did their island counter- parts; the reverse was true for the vireo. It is not yet known whether the increased feeding diversity reflects changes in the behavior of single indi- viduals or different degrees of polymorphism (more strictly, polyethism) in the population as a whole. Since Crowell’s mainland observations were not limited to a small area, this is a point that must be examined. It is premature to interpret these results as either favoring or invalidating our hypothesis concerning the causes of tropical diversity. Samples including far more individuals and species will first be needed to fill gaps in the ex- perimental design. However, a number of interesting, if tentative, conclusions can be drawn from these data. To begin with, given a situation in which the number of potentially com- peting species is reduced, as occurs on islands with an impoverished fauna, at least one tropical species ( specifically, the Bananaquit I apparently has no difficulty expanding into habitats in which, on adjacent mainland, it does not occur. By “habitat” we mean morphologieally defined ( generally in terms of foliage-height diversity ) plant assemblages. On continental land masses such assemblages have particular bird species associated with them DISCUSSION Peter H. Klopfer BEHAVIORAL STEROTYPY IN BIRDS 299 CATBIRD CARDINAL WHITE-EYED VIREO 425 629 Fig. 7. Crowell’s (1962) comparison of the feeding methods (pecking off ground, foliage-gleaning, bark-gleaning, feeding while hovering, hawking) of Catbirds, Cardinals, and White-eyed Vireos in North America and on Bermuda. The numliers show the frequency of the feeding method as observed at 10-second intervals; H is the measure of diversity in feeding methods. ( MacArthur, pers. comm, and 1965). Either these island birds show less selectivity in their choice of habitat or else the features of different habi- tats relevant to them are not associated with foliage-height diversity, as on the mainland. The data here presented ( and those of Crowell, 1962 and MacArthur, 1965) suggest the former to be more likely. Thus, while as a consequence of early learning experiences, tropical birds may in fact prove more “stereotyped” in their actual behavior than temperate zone species (Klopfer, 1965), the responses of these same tropical birds on islands indi- cates they have a tremendous capacity for “plasticity.” That this is a true ontogenetic plasticity is evident from the catholicity shown by the hand- reared birds. Thus, it would appear that while tropical species on tropical mainlands are in fact “stereotyped,” this is more likely an effect rather than a cause of their greater diversity. SUMMARY The foliage preferences of hand-reared tropical birds are relatively broad. Exposure to a particular type of foliage narrows these preferences. Previous experiments ( Klopfer, 1%5) had shown that certain temperate zone birds had narrower preferences whether wild-trapped or hand-reared. The motor patterns of tropical species were shown capable of considtuahh* modification. 300 THK WILSON BULLETIN Scptciiilicr 1967 \ 79, No. 3 ACKNOWLEDGMENTS 'I'liis work was supported in part hy an NIH career Development Award and NIH (irant #04453. Travel supjiort was also provided hy the Chapman Fund of the American Museum. 1 am indebted to J. Potter and j. Reiss for their assistance, and to .). J. Hatch for critical comments. Able assistance in the field was rendered hy Barrie (iilhert and Dr. Wolfgang Schleidt. LITEExATURE CITED CltOVVELL, K. 1962 Reduced interspecific competition among the birds of Bermuda. Ecology. 43:75 87. In press Changes in the ecology of Bermuda birds. Kl()i>feh, P. H. 1962 Behavioral Aspects of Ecology. Prentice-Hall, Inc., Englewood Cliffs, New Jersey. 1965 Behavioral aspects of habitat selection; a preliminary report on stereotypy in foliage preferences of birds. Wilson Bull., 77:376-381. MacAkthuh, R. H. 1965 Patterns of species diversity. Biol. Rev., 40:510 533. MacAhtiilih, R. H., j. MacAuthuh, and J. Pheeh 1963 On bird species diversity; prediction of bird census from habitat measure- ments. Amer. Nat., 96:167-174. Tate, M. W., and R. C. Clelland 1957 Nonparametric and shortcut statistics. Interstate Pub., Inc., Danville, 111. VAN VaLEN, L. 1965 Morphological variation and width of ecologic niche. Amer. Nat., 99:377-390. DEPARTMENT OF ZOOLOGY, DUKE UNIVERSITY, DURHAM, NORTH CAROLINA, 31 MAY 1966. SOME COURTSHIP DISPLAYS OF THE GOLDEN-WINGED WARBLER James Baird Despite the fact that the Golden-winged Warbler ( V errnivora chrysoptera) has been of exceptional ornithological interest for more than 75 years because of its interbreeding with the Blue-winged Warbler (V. pinus), re- markably few ethological observations have been published ( see Ficken and Ficken, 1962 ) . In view of this general lack of behavioral information, it seems worthwhile to publish the following observations on Golden-winged Warbler displays. The terminology, where applicable, follows that of Ficken ( 1963 ) . DISPLAYS Gliding. — On 15 May 1962 a male Golden-wing was observed Gliding at the Cambridge Reservoir, Lexington, Middlesex County, Massachusetts. The context of the Glide was not determined, but briefly what was observed was that the male, which had been singing steadily for a half hour, flew to the top of a tall dead tree, took off, set his wings and Glided to a nearby tree from which he immediately Glided again ( Fig. 1 ) , No other bird was visible. Unlike the Redstart ( Ficken, 1962 ) , the male did not spread his tail during the Glide. Courtship feeding. — In the late afternoon of 14 May 1964 in Lincoln, Middlesex County, Massachusetts, a female Golden-wing was found feeding halfway up a white pine {Pinus slrobus). In order to obtain a closer look, I started “squeaking” and immediately a male Golden-wing appeared in a maple adjacent to the pine, chipped a few times, and flew down to sit about 6 inches away on the same branch as the female. At once the female raised her bill and fanned her tail so that the white flashed conspicuously ( Fig. 2a ) . She then thrust her head towards the male and gaped ( Fig. 2b I . The male. Fic. 1. Male Lolden-winjred War!)ler (diding. 301 302 THE WILSON BULLETIN Sei)teml)er 1967 Vol. 79, No. Fig. 2. Agonistic displays of Golden-winged Warblers, either simultaneously or shortly thereafter, sleeked his plumage and raised his head and pointed his hill upwards at a 45 degree angle ( Lig. 2c I . As far as could be seen, he did not fan his tail. The female flew and the male fol- lowed at once; they then separated, the female foraging low and the male feeding high in an oak. A few minutes later the male flew down to the female, which was perched on a low dead shrub, and fed her a caterpillar. In feeding the female, the male perched beside her with his body and head held high and his bill point- ing down. As the male alighted, the female crouched, turned her head towards him and raised her bill and accepted the caterpillar ( Lig. 3 ) . It was not noted whether she wing-quivered. Fig. 3. Courtship Feeding by male Golden-winged Warbler. James Baird GOLDEN-WINGED WARBLER DISPLAYS 303 Fig. 4. Courtship Display of male Golden-wiiiged Warbler: fluffed display given while following the female. Although a male had been heard singing in this locale earlier in the day, this male did not sing during any of these displays. The female did quite a hit of chipping ( largely in response to my “squeaking” ) ; her most frequent note was a very short tchip and occasionally a dry rattle. During this half-hour observation period, the male Golden-wing was seen to chase a male Prairie Warbler {Dendroica discolor), a male Magnolia Warbler ( Dendroica magnolia ) , a Parula Warbler ( Panda americana ) and a Nashville Warbler {V ermivora rujicapilla) . Courtship display. — On the afternoon of 17 May 1965 in Lincoln, Middle- sex County, Massachusetts, 1 observed a female Golden-wing foraging along the edge of an alder thicket that bordered the road. A male Golden-wing was persistently following her and continually orienting his head towards her 304 THE WILSON BULLETIN Sp|)tonihcr 1967 \ Ol. 79. No. .1 Fig. 5. Courtship Display of male Golden-winged \'i'arl)ler: hovering flight display. (when beneath her, he looked up; when above her, he looked down, when to one side, he looked towards her I . During this following, his crown feathers were raised and his cheek and throat feathers were fluffed. His tail was continually being fanned ( opened and shut ) , thus showing the white mark- ings, and occasionally waved from side to side ( Eig. 4l. The male followed the female in this fashion for a full five minutes. Then he suddenly crouched, raised and spread his tail, raised his wings and started to vibrate them very rapidly, while lifting his head high, and raising his crown feathers ( Eig. 5 I . He then assumed a more normal posture, hopped towards, and resumed fol- lowing the female. Again he raised his tail, spread it, raised his wings, vi- brated them, and this time actually flew to within eight inches of the female, where he hovered briefly, and then, with his wings still upraised and vibrat- ing, made a rapid, sideways flight around the female in an arc of about two feet. He attempted to land either on or near the female but she pecked at James Baird GOLDEN-WINGED WARBLER DISPLAYS 305 him and he flew away in a normal flight. This was repeated again. Although my attention was focussed on the male, I am reasonably certain that the fe- male maintained a “normal” posture during these displays. Because of the fragmentary nature of the above observations, detailed dis- cussion of their ethological significance is not possible, however, since ap- parently none of these displays have been reported in the literature, some comment seems justified. DISCUSSION Although Gliding in warblers has been shown to be an expression of both agonistic and sexual behavior ( Eicken and Eicken, op. cit. ) , it seems likely that the Gliding I observed was a sexual display ( despite the fact that a sec- ond bird was not seen ) , since M. S. Eicken informs me ( pers. comm. ) that she has seen “. . . . Gliding several times in both Golden-wings and Blue- wings,” and that it “definitely seem part of the courtship ceremony (rather than agonistic ) .” The observation on Courtship Eeeding was preceded by displays by both sexes, which were apparently initiated by the male violating the female’s individual distance. The female reacted to the male’s intrusion by Bill Rais- ing, Tail Banning, and then giving a Head Eorward display (including Gap- ing) ; the male responded by Bill Raising and sleeking his plumage. The most unusual aspect of these essentially agonistic displays was the Bill Raising by both the male and the female. Eicken and Eicken ( op. cit. ) considered that Bill Raising is “apparently lacking in warblers (except the Ovenbird (Seiurus aurocapillus ) ) .” Equally interesting was the Courtship Eeeding which was observed witbin minutes after the previous displays. Courtship Eeeding has not been reported for the Golden-wing and is apparently rare among warblers; Nolan (1958) found evidence of Courtship Eeeding in only “three or four” of 21 parulids reviewed. However, incubation feeding has been reported for many warbler species (Nolan, op. cit.), and a male Brewster’s Warbler has been seen to feed his mate, an incubating female Golden-wing, on the nest (Carter, 1941). The actions and the feather postures adopted by the male during the Court- ship display were similar to those reported for other warblers ( Eicken and Eicken, op. cit. — see especially Table IV, p. 115). Particularly noteworthy were the persistent following movements by tbe male during which the head with its striking markings was directed towards the female, and the display flight, whieh emphasized the golden wing bars, and the white in the tail. As Eicken and Eicken (op. cit.) point out such displays as fluffing the ])lumage and moving the wings tend to accentuate the species-typical markings. 306 THE WILSON BULLETIN Se[)teinl)er 1967 Vol. 79, No. .1 SUMMARY Tliree sexual displays previously unreported for the Golden-winged Warbler are described: Gliding, Court.sbip Feeding, and a Gourtship display. The behavior of the male during the Gourt.sbip dis()lay was similar to that of other parulids, involving such (lisjilay components as plumage fluffing, crown raising, wing movements, etc. ACKNOWLEDGMENTS I would like to thank Dr. Millicent S. and Dr. Robert W. Ficken for reading the manuscript and making several helpful suggestions. LITERATURE CITED Garter, T. D. 1944 Six years with a Brewster’s Warbler. Auk, 61 :48-61. Ficken, M. S. 1962 Agonistic behavior and territory in the American Redstart. Auk, 79:607-632. 1963 Courtship of the American Redstart. Auk, 80:307-317. Ficken, M. S., and R. W. Ficken 1962 The comparative ethology of the wood warblers (Parulidae): a review. Liv- ing Bird, 1:103-122. Nolan, V., Jr. 1958 Anticipatory food-bringing in the Prairie Warbler. Auk, 75:263-278. MASSACHUSETTS AUDUBON SOCIETY, LINCOLN, MASSACHUSETTS, 22 APRIL 1966. NEW LIFE MEMBER Mr. Clive Goodwin, of Weston, Ontario, has recently become a Life Member of Tlie Wilson Ornithological Society. A graduate of the University of Toronto, Mr. Goodwin is Executive Director of the Conservation Council of Ontario. He is a member of the AOU, BOU, and British Trust for Ornithology, as well as The Federation of Ontario Naturalists, for which he served as editor of Ontario Natu- ralist and Young Naturalist. He has also served as Regional Editor for Audubon Field Notes. He has published numerous papers in local journals on his principal ornithological interests, bird populations and migrations. Mr. Goodwin’s other in- terests include photography, biophilately, and music. FOOD AND FEEDING HABITS OF AUTUMN MIGRANT SHOREBIRDS AT A SMALL MIDWESTERN POND William S. Brooks Most shorel)ircls in migration traverse so great a distance and so many ecologically different areas that it is improbable that they are able to maintain a very specific diet. Whereas they might feed, for example, mainly on certain dipteran larvae on the breeding grounds, they may not find these available during migration. Thus they must turn to other types of food and broaden their feeding niches. This may cause greater dietary over- lap and competition between species. Although some overlap is to be expected, there are differences in the basic feeding patterns and size differences which preclude total overlap between species. It is the purpose of this study, besides adding to the sparse knowledge of foods of migrating birds, to demonstrate that while there is considerable overlap in the diets of several species of shorebirds during autumn migration, there are differences which indicate at least partial segregation into different feeding niches. The data were gathered in conjunction with a migration study done in 1960 and 1961. Observations were made and sampling was done at a shallow mud- bottom pond approximately % mile north of Champaign, Illinois. This was apparently the only suitable feeding place for shorebirds in the area, and it is probable that the birds collected had consumed their food there. METHODS Varying numbers of nine of the 20 species under observation were col- lected with a shotgun for stomach analysis during the autumn migration: Common Snipe (Capella gallinago) , 5 in October, 1961; Greater Yellowlegs iTotanus melanoleucus) , 2 in October, 1960, one in November, 1961; Lesser Yellowlegs iTotanus flavipes), 4 in September and 2 in October, 1960, 3 in October, 1961; Pectoral Sandpiper [Erolia melanotos ) , 2 in October, 1960, and 1 in October, 1961, 4 in July, 1961; Least Sandpiper [Erolia miniitilla) , 1 in October, 1960, 3 in July, 1961; Dunlin {Erolia alpina) , 2 in October, 1961; Stilt Sandpiper (Micropalama hiinantopus ) , 2 in October, 1960; Semi- palmated Sandpiper (Ereunetes pusilliis), 2 in August, 1961; Wilson’s Phalarope (Steganopus tricolor)^ 1 in July, 1961. The digestive tract was removed no later than one hour after death and preserved in 70 per cent ethanol. The contents of esophagus, proventriculus, and ventriculus were later emptied into a shallow dish and the parts of each type of food organism separated into groups using a binocular dissecting 307 308 THE WILSON BULLETIN Septenil)er 1967 Vol. 79, No. .3 microscope. The number of organisms making up each group and the per- centage that these made up of the total number of organisms in the stomach was then determined. In the cases where it was considered that plant material was jmrposefully ingested the jiercentage by bulk of this material was esti- mated, and the percentage of other organisms calculated on the remainder, as above. The pond bottom was sampled throughout the year to determine the kinds and numbers of benthic organisms available to the birds by pushing a brass cylinder of 0.0077 m“ area into the substrate to a depth of 10-15 cm, washing the contents through a 1.5 mm mesh sieve, and counting the organisms. Sampling locations were randomly selected in water 15 cm or less deep in the general areas where the birds fed. Varying numbers of samples were taken 2 to 4 times a month during migrations, and once a month at other times of the year. Mats of filamentous algae formed over much of the pond’s surface in late summer and autumn, creating a new feeding substrate for the smaller shore- birds in particular. Lree-swimming, algal-mat, and shoreline food organisms were not sampled quantitatively hut relative numbers were established by observation on the days when bottom samples were taken. RESULTS AND DISCUSSION In addition to the benthic organisms (Table 1 ), northern fathead minnows ( Pimephales prornelas: Cyprinidae ) and numerous free-swimming adult aquatic beetles were present. Relative numbers of the fish could not be de- termined but, of the insects, Dytiscidae made up approximately 50 per cent, Haliplidae ( crawling water beetles ) , 30 per cent, and Hydrophilidae, 20 per cent. Their relative numbers did not appear to change significantly during the migration period. Other aquatic insects were present but in very small numbers. Non-aquatic insects made up about 60 per cent of the available shoreline and algal-mat organisms during the entire migration period, stratio- myid (soldier fly) larvae, 30 per cent, and haliplid larvae, 10 per cent. Terrestrial insects of various species were commonly found trapped on the water surface, and wind-blown concentrations were often found against and on the algal mats. Specificity of diet concerns the number of different food items consumed by a species. By these terms the Lesser Yellowlegs would be least, and the Stilt Sandpiper most specific (Tables 2 and 3), but the small and unequal sample sizes do not permit any conclusion here. It is probable that the larger species are less specific than the smaller ones, since they are not as restricted to the shoreline or to relatively smaller organisms. William S. Mrouks SHOREBIRI) FEEDING HABITS 309 Table 1 Dknsitiks^ of Benthic Organisms Jau. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Oryaiiism (3)^ (2) (4) (7) (4) (3) (7) (11) (15) (8) (4) (2) Pliysidae (snails) 130 65 130 334 1,203 650 1,021 1,076 966 748 390 130 Chironomidae (midge flies) larvae, pupae 173 195 111 293 130 111 166 337 211 98 65 Diptera (flies) larvae, pupae 87 228 74 163 216 74 142 57 33 131 65 Corixidae (water boatmen) 163 56 98 43 37 154 61 98 98 Baetidae ( may- flies) naiads 33 43 56 59 132 65 Hydropliilidae ( water scav- enger beetles) larvae 65 43 56 24 20 16 Anisoptera ( dragonflies) naiads 19 65 43 12 1 16 Coenagrionidae ( damselflies) naiads 33 43 12 Dystiscidae ( predaceous diving beetles) larvae 43 24 16 1 Individuals per m^. 2 Number of samples. Selectivity of diet concerns the relation between the quantity of a certain food item available and the quantity consumed. The forage ratio of Hess and Swartz ( 1941 ) , calculated by dividing tbe per cent of a food item in the stomach by the per cent of that item in the fauna, gives a measure of the selectivity of an animal for the components of its diet. A value of less than unity denotes that the item is not selected in relation to its abundance; unity, that it is selected in direct relation to its abundance; greater than unity, that it is selected out of proportion to its abundance or that it is a preferred item. The forage ratios (Tables 2 and 3) show that most of the species were apparently selective for several items in their diets but had at least one item of high preference peculiar to each. Lack (1945) concluded that closely related species differ in one or more of the following: habitat, region, or diet. Two closely related phalacrocora- 310 THE WILSON BULLETIN Sp|itcml)('r 19f)7 Vol. 79, No. 3 cicis, very similar in appearance, habitat, and region “differ markedly in both nesting sites and food.” Dietary selectivity is the major differing factor in the niches of these species which can account for their coexistence without contradicting Cause’s rule. He found ( 1914 ) that in many closely related sympatric passerines dietary differences were important in their ability to coexist. This is now a rather well-known ecological fact, but his and others’ observations have concerned only breeding or permanent resident birds. Lack stated (1944:276) that “closely related species are potential food com- petitors in winter, and so have evolved geographical isolation at this sea- son . . . ,” and suggested that off the breeding grounds ( during migration and on the wintering grounds ) their food may become more similar. The results of the present study, however, indicate that the identities of separate feeding niches may be maintained through migration, or, in light of Holmes’ (1964) finding, that the feeding niches of congeneric species of sandpipers almost completely overlapped during the breeding season, the niches may even become more divergent. Competition should be greater for preferred food items than for others. In cases where two or more species shared a high preference, they usually did not compete, because their feeding areas were different. However, during the peak of migration, in early September both years, competition should have been and apparently was keenest between species which had common pre- ferred food items and common feeding areas. Lesser Yellowlegs and Pectoral Sandpipers (the first and second ranked species at the pond with respective 4-month averages of 14 and 12 birds seen per trip to the area and peak num- bers of 125 and 50) both selected hydrophilid larvae, and aggressive en- counters between these two species were the only ones seen, being most noticeable in early September. Close study was not made of this behavior, and although Hamilton’s (1959) “crouch” and “supplanting” displays by Pectoral Sandpipers were the only ones noticed, there were no doubt other aggressive displays that I did not recognize. This behavior was shown usually between Pectoral Sandpiper individuals, less often between these and Lesser Yellowlegs, with the former being the apparent aggressor. The Least Sand- piper also selected hydrophilid larvae but no aggressive displays were noted involving this species, although less obvious displays, sufficient to cause the smaller species to move away without apparent conflict, could have been em- ployed by the larger sandpipers. No encounters between Stilt Sandpipers and Lesser Yellowlegs were ob- served, although they both selected chironomid larvae and corixids. Either the supply was sufficient or the fact that the former habitually fed in deeper water may have eliminated competition. There was no competition for chironomids between Lesser Yellowlegs and Least Sandpipers, since the Food Habits of the Shoreline-frequenting Shorebirds W illiai Brooks SHOREBIRI) FEEDING HABITS 311 pu: £ £ Qo^ OJ-O hJ c’^ Tt o CM 00 o • ^ O • r-; VO O iro O CO O CO CO O CO t— I c5 o V p _0J ^ ^ 2 ^ -p a g a O Q U ffi Q r-l CM o o CM ^ ^ (N CO lO d d CM CO d d CO LO d d Tt q o ^ - O vOi CO O O CO PH* CM d d o .2 03 s ’O <1^ a s .2 q'w ^ Co •2^1 C3 OJ ^ >1 C3 CO 5 Sample size. 3 Per cent of item in diet. Frequency, per cent of stomachs containing item. 4 Forage ratio, values > 1 in boldface. Table 3 Food Habits of the Shorebirds feeding away from Shore 312 THE WILSON BULLETIN September 1967 Vol. 79, No. 3 a Q> “io 2^ Tf 'O o ^ q ^ L v‘ CO ; o o o V I'- rH O CO 10 ^ 10 lO + -a c n I I £ U Q u P3 X (U a, I S •S s c3 ^ c/j q . ~ “O " ^ I 's o !s ^ ® s .22 q . 7:: ^ P* ?L) - — — — ~ - CO c CJ ^ C X CJ O CO o q _22 “ S ^ i CO Sample size. 3 Per cent of item in diet. Frequency, per cent of stomachs containing item. 4 Forage ratio, ^■alues > 1 in boldface. SHOREBIKI) FEEDING HABITS 313 former generally probed the bottom and the latter took only pupae which had come to the surface and were washed ashore or against the algal mats. It is possible that the aggressive behavior described above was not due to active competition for a food item but to the preservation by the birds of their “individual distances.” Hamilton (1959) reports that when this distance is reached, threatening usually occurs among Pectoral Sandpipers. However, he did not mention that this occurred interspecifically in the general feeding area, and for this reason active competition cannot be excluded as being re- sponsible for the aggressive behavior shown between species in the present study. Several species examined had eaten considerable plant material. Forage ratios could not be calculated for this type of food but the high frequencies and percentages of seeds taken by the Common Snipe and Pectoral Sand- piper, and of algae by the snipe and Semipalmated Sandpiper indicate that they were selecting this over animal food in some instances. Plant material was present in almost all stomachs examined but was usually in very small amounts and was considered to have been taken incidentally with animal food by all except the species mentioned above. Of interest is that while adult haliplid beetles composed about 30 per cent of the free-swimming fauna, not one was found in the stomachs. The reason for their apparent unpalatability may be that they have an extremely thick and hard external covering and are very resistent to crushing. If they can- not be crushed they obviously have little food value. Little correlation can be made between temporal changes in densities of food organisms, number of birds present, and dietary changes of the birds, due to the relatively small number of stomachs examined. Forage ratios should reflect a change of any sort (or no change) when comparing a species of shorebird at different times. The Lesser Yellowlegs, for which the most samples are available, is taken as an example. Of those food items for which the ratio was greater than unity in either September or October (see Table 3) the density of hydrophilid larvae decreased about 20 per cent, mayfly naiads, 50 per cent, and chironomid larvae and pupae, 33 per cent, while corixids increased about 33 per cent. The respective forage ratios decreased about 50 per cent, increased 20 per cent, decreased 100 per cent, and in- creased about 33 per cent. Although the data do not permit a conclusion, it is attractive to speculate that as the density of one preferred organism de- creases, the birds feed more intensively on another preferred organism for which the density has increased. This, of course, follows the established ecological principle that as a population decreases or increases, external pres- sures such as predation tend to decrease or increase with it. The size of the bird, or more accurately, the leg-length, appeared to in- 314 THE WILSON BULLETIN Seplf’ii'l'fr 1967 Vol. 79, No. 3 fluerice the food of the different speeies. The smaller or short-legged species usually did not feed in deeper water, taking organisms available on the shore, the algal mats, or in very shallow water. Greater numbers of free-swimming and terrestrial forms were consumed by them, in contrast to the larger speeies, which took more benthic organisms (see Tables 2 and 3 respectively). It should be mentioned here that the Least Sandpiper collected in October and the Wilson’s Phalarope in July, omitted in the tables, had eaten only non- aquatic insects. On the basis of the food habits, general size of the birds, main feeding sites, and tendency to feed together, the 20 species present at the pond during the study can be placed into three feeding groups: Group I. Larger species which fed exclusively on the shore: Killdeer iCharadrius vocijerus) . American Golden Plover { Pluvialis dominica) , Black-bellied Plover {Squatarola squatarola) ^ Buff-breasted Sandpiper ( T ryngites su hru ficollis ) . Group II. Smaller or short-legged species which fed on or near the shore or on the algal mats: Semipalmated Plover i Charadrius semipalmatus) , Gommon Snipe, Spotted Sandpiper i Actitis macularia) , Pectoral Sandpiper, Baird’s Sandpiper iErolia bairdii) , Least Sandpiper, Dunlin, Semipalmated Sandpiper, Western Sandpiper (Ereunetes mauri), Sanderling (Cro- ce thia alba) . Group III. Larger species which fed most commonly in water up to belly- deep: Solitary Sandpiper [Trin^a solitaria) , Greater Yellowlegs, Lesser Yel- lowlegs. Short-billed Dowitcher { Limnodromiis griseus). Stilt Sandpiper, Wilson’s Phalarope. There were individual exceptions, but as a rule these groups were distin- guishable in the field. A zonation was evident, with Group I at the periphery, Group II near the water’s edge, and Group III located out in the water. The Lesser Yellowlegs was ubiquitous but more often fed in deeper water away from shore. It has been somewhat arbitrarily placed in Group III rather than in Group II. The Wilson’s Phalarope possibly should be grouped by itself. Although it fed with the others of Group III, the specimen collected had consumed 100 per cent non-aquatic insects, as mentioned above. Apparently it took float- ing insects from the surface of the water and from algal mats, unlike the others. SUMMARY The general feeding habits of 20 species of shorehirds at a small pond near Cham- paign, Illinois, were observed and stomach analyses of nine of these species were made William S. llrooks SHOKEBIKI) FEEDING HABITS 315 (luring the autumn migrations of 1960 and 1961. The numbers and kinds of availal)le food organisms at the pond were estal)lished l)y (juantitative sampling of henthic in- vertebrates and estimation of relative numbers of free-swimming and shoreline orga- nisms. Although most species did not show dietary specificity, consuming a rather wide array of organisms, all showed dietary selectivity, in that one or a few of the food items were sought out over the others and out of proportion to their abundance. Competition was probably reduced by this selectivity, and where two species shared high preference for the same item, competition was alleviated by the fact that they usually fed at different sites. Aggressive behavior was observed intraspecifically with the Pectoral Sandpiper, and at the peak of migration, interspecifically between these and Lesser Yellowlegs. They may have been actively competing for a preferred food item common to both. The Common Snipe, Pectoral Sandpiper, and Semipalmated Sandpiper appeared to consume considerable amounts of plant material intentionally. The other species prob- ably took it incidentally with animal food. The size or leg-length of the bird partially determined its diet. Small species were apparently unable to forage in deeper water or ingest large organisms. The 20 species were placed into three groups on the basis of their food, general size, main feeding sites, and tendency to feed together. These groups, when feeding, were distinguishable in the field because of iheir evident zonation. ACKNOWLEDGMENTS I greatly appreciate the help and advice given me by S. Charles Kendeigh during the study. Thanks are due John E. Williams for his aid in obtaining specimens for stomach analysis. For identifications of various food organisms I am indebted to Mrs. Leonora K. Gloyd, John M. Kingsolver, Milton W. Sanderson, and Philip W. Smith of the Illinois Natural History Survey. This report is based on a portion of a master’s thesis in the Department of Zoology, University of Illinois. LITERATURE CITED Hamilton, W. J. 1959 Aggressive behavior in migrant Pectoral Sandpipers. Condor, 61:161-179. Hess, A. D., and A. Swartz 1941 The forage ratio and its use in determining the food grade of streams. Trans. Fifth North Amer. Wildl. Conf., 1940:162-164. Holmes, R. T. 1964 Food overlap in breeding sandpipers in northern Alaska (Abstract). Proc. 14th Alaskan Sci. Conf., Anchorage, 1963:66. Lack, D. 1944 Ecological aspects of species-formation in passerine birds. Ibis, 86:260-285. 1945 The ecology of closely related species with special reference to Cormorant {Phalacrocorax carbo) and Shag (P. aristotelis) . J. Animal EcoL, 14:12-16. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF ILLINOIS, URBANA, ILLINOIS (PRES- ENT ADDRESS: DEPARTMENT OF BIOLOGY, RIPON COLLEGE, RIPON, WISCONSIN 54971), 21 MARCH 1966. CICO.MA MALTHA AND GRIS AMERICAS A FROM THE UPPER PLIOCENE OE IDAHO J. Alan Feduccia Recent paleontological collecting by Claude . Hibbard and his field assistants has yielded a large array of avian fossils from Idaho. The specimens reported herein were collected from the Glenns Ferry Formation. Twin Falls County. Idaho, and constitute part of the Hagerman Local Fauna, which has been assigned to the Upper Pliocene ( Hibbard et al.. 1965 ). The best estimate of the age of this fauna on the basis of potassium-argon dating is considered to be 3.48 = 0.27 million years ( Evernden et al.. 1964. p. 191). Ciconia maltha has been reported previously from the Lpper Pliocene of Idaho I Miller. 1944 » . but the locality from which the specimens were taken, the Bruneau Eormation. has more recently been assigned to the Middle Pleistocene i see 5Ialde and Powers. 1962 1 . This species has also been re- ported from numerous Lpper Pleistocene localities (see Brodkorb. 1963). Grus americana has been reported from the Glenns Eerry Eormation (13 miles NA^ of Grandview. Idaho) on the basis of a tibial fragment (Miller, op. cit. ). and from several Pleistocene localities i see A etmore, 1956 ). In the course of this study I examined Recent specimens of Jahirii mycteria, Eiixenura ma^iiari, Ciconia ciconia, Grus americana, and Grus canadensis in the skeletal collection of the Lniversity of Michigan ^Museum of Zoology. A scapula of Ciconia maltha from the type locality of Rancho La Brea, and skeletal elements of Recent Grus americana were kindly loaned by Theodore Downs of the Los Angeles County Museum of Natural History and Clayton M. A hite of the Lniversity of Kansas Museum of Natural History, respec- tively. All of the specimen numbers refer to the Lniversity of Michigan 5Iuseum of Paleontologv unless otherwise indicated. DESCRIPTION OF M ATERIAL Ciconia maltha. Specimen: Proximal 69 mm of right scapula (4MMP 52540 », from the Hagerman quadrangle, SE ^4 sec. 29. T7S, RISE, 1.850 feet and 1.100 feet A of SE corner of sec. 29. elevation 3.125 feet. Measurement: maximum breadth of head. 26.1 mm. There has been considerable uncertainty in the past regarding the number of species of fossil storks (excluding the Mycteriinae) recorded from Aorth America. Howard ( 1942 > examined all of the then known specimens and concluded that all represented one highly variable species. C. maltha. I have examined scapulae from four sp)ecimens of Jahiru mycteria. a form that closely approximates C. maltha in size and in osteological characters, and have found not only variation in size, but also in osteological characters of the scapulae. It is therefore not surprising to find individual bones that do not conform in all details to the presently known specimens of C. maltha. The fossil re- ported herein differs from the scapula of C. maltha (Los Angeles County Museum of 316 ,1. Alan Fcdiiccia PLIOCENE STORK AND CRANE 317 Natural History B8120) that I examined and from the description of scapulae of C. maltha (Howard, 1942, p. 196) in the following characters: concavity hetween acromion and glenoid facet slightly deeper, and the depression at the base of the dorsal surface of the coracoid articulation somewhat more depressed. However, both of these char- acters vary somewhat in the specimens of Jabiru that I examined. The Hagerman fossil agrees with the scapula of C. maltha in general form, the region of the base of the scapula mesial to the coracoid articulation being straight (in Jabiru the same region is well rounded) and coming to an abrupt end at the furcula articulation. This region of the base in the Hagerman fossil and in C. maltha is perforated by pneumatic foramina. Scapulae of Ciconia ciconia and Euxenura maguari are similar to those of the Hagerman fossil and the specimen C. maltha in general contour of the basal region, hut the de- pression under the coracoid articulation is absent in Euxenura and only slightly de- pressed in C. ciconia. In size, the Hagerman scapula and that of C. maltha overlap with Jabiru mycteria and are larger than either Euxenura maguari or C. ciconia. The differ- ences in osteological characters hetween this fossil and C. maltha are not, in my opinion, sufficient to warrant recognition of a new species. Grus americana. Specimens: (1) Fragment of proximal 53 mm of left coracoid (UMMP 48927), from the Hagerman quadrangle, SW ^ NW sec. 16, T7S, RISE, elevation 3,025 to 3,100 feet. Measurements: least width of shaft, 13.8 mm; least depth of shaft, 9.4 mm. (2) Left quadrate minus orbital process (UMMP 52249), from the Hagerman quad- rangle, SE 1/4 SW lA sec. 5, T8S, RISE, 1,400 feet E and 250 feet N of SW corner of sec. 5. Measurement: greatest distance from squamosal articulation to mandibular articulation, 18.2 mm. (3) Distal 93 mm of left tihiotarsus (UMMP 52541), from the Hagerman quadrangle, NE lA NE 1/4 sec. 32, T7S, RISE, 850 feet S and 1,100 feet W of NE corner of sec. 32, elevation 3,050 feet. Measurements: depth through condyles, 23.2 mm; width of condyles, 23.0 mm. (4) Fragment of distal end of right tihiotarsus (UMMP 52288), from the Hagerman quadrangle, NW lA NE lA sec. 16, T7S, RISE, 800 feet S and 2,600 feet W of NE corner of sec. 16, elevation 3,010 feet. This bone appears to be that of a large crane hut is so fragmentary that specific designation seems inadvisable. (5) Fragment (155 mm) of proximal end of right tarsometatarsus (UMMP 52242), from the Hagerman quadrangle, SE % NE lA sec. 17, T7S, RISE, elevation about 3,225 feet. No useful measurements could he taken from this fragment. (6) Distal 51 mm of right tarsometatarsus minus trochleae for digits HI and IV (UMMP 52243), from the same locality as UMMP 52242. Measurement: greatest antero- posterior distance through trochlea for digit II, 12.7 mm. I have examined the following hones of the Recent form: four coracoids, quadrates from one skull, five tarsometatarsi from four specimens, seven tihiotarsi from four speci- mens, plus six complete skeletons of Grus canadensis. Grus americana, like Ciconia maltha, varies both in size and in osteological characters of hones. All of the specimens reported herein are intermediate in size hetween the largest and smallest of the Recent Cr. americana that I examined, and are well accommodated into the range of variability of osteological characters. Although the possibility exists that the fossils reported herein do not actually represent the same biological species as Recent G. americana, the hones appear to he inseparable from those of the Recamt form. 318 THE WILSON BULLETIN September 1907 Vol. 79, No. ACKNOWLEDGMENTS I am indeltted to Dr. Claude W. Hiltltard for permission to study the fossils and for supervision throughout this study, and to Dr. Robert W. Storer for criticizing the manuscript. Mr. B. G. Murray, .Ir., did considerable work in sorting the Hagerman fossils. LITERATURE CITED Brodkorb, P. 1963 Catalogue of fossil birds. Part 1 ( Archaeopterygiformes through Ardei- formes). Bull. Florida State Mus., 7:180 293. Evernden, J. F., D. E. Savage, G. H. Curtis, and G. T. James 1964 Potassium-argon dates and the Cenozoic mammalian chronology of North America. Amer. J. Sci., 262:145-198. Hibbard, C. W. 1965 Quaternary mammals of North America hi The Quaternary of the United States ( H. E. Wright, Jr., and 1). G. Frey, Eds.), Princeton Univ. Press, Princeton, N.J., pp. 509-525. Howard, H. 1942 A review of the American fossil storks. Carnegie Inst. Wash., Puhl. 530: 187-203. Maude, H. E., and H. A. Powers 1962 Upper Cenozoic stratigraphy of Western Snake River Plain, Idaho. Geol. Soc. Amer. Bull., 73:1197-1220. Miller, L. 1944 Some Pliocene birds from Oregon and Idaho. Condor, 46:25-32. Wetmore, a. 1956 A check-list of the fossil and prehistoric birds of North America and the West Indies. Smithsonian Misc. Coll., 131:1-105. MUSEUM OF ZOOLOGY, THE UNIVERSITY OF MICHIGAN, ANN ARBOR, MICHIGAN, 11 MAY 1966. SEED-SIZE PREEERENCE IN CHICKADEES AND TITMICE IN RELATION TO AMBIENT TEMPERATURE Becky A. Myton and Robert W. Ficken COMPETITION for food between two closely related, sympatric species can be assayed in four ways — differences in feeding habits, feeding loca- tions, nature of food, and size of food ( Hinde, 1959). The original object of this study was to test the seed-size preference of two sympatric species, the Carolina Chickadee ( Parus carolinensis ) and the Tufted Titmouse {P. bicolor). A direct correlation has often been observed between the size of food taken and the size of the bill of the bird ( Lack, 1947; Snow, 1954; Betts, 1955; Morris, 1955) ; hence, we hypothesized that chickadees would prefer smaller seeds while the larger-billed titmice would prefer larger ones. Further, we predicted that both species would be most efficient at husking and eating the size they preferred. It became apparent soon after observations began that the chickadees took more of the larger seeds on colder days. The objective was therefore expanded to test for corre- lation between temperature and seed-size preference. MATERIALS AND METHODS Feeders were attached four feet up on large trees at four well-separated locations in deciduous woods near College Park, Maryland. The feeders were flat plastic trays measuring 12 X 30 inches with a 1 inch rim. Observa- tions were begun on 17 November 1964, and continued through 22 February 1965. Two size groups of sunflower seeds, dyed black with India Ink, were placed on one or the other side of each feeder; the large-seed group was 0.12-0.17 g and the small-seed group was 0.03-0.07 g. The two size groups were shifted randomly in order to minimize the effect of position. To test for randomness of choice on each side of the feeder, observations were ob- tained on mixtures of both sizes. Data taken included seed size (large or small) chosen, the amount of time spent husking and eating, and ambient temperature. RESULTS Control for position effect. — Virtually the same number of seeds of mixed size was chosen from the right side of the feeder (78) as from the left (75) by a flock including several birds of both species, thus indicating no prefer- ence for a particular side. Time spent husking and eating. — The relative efficiency of the two species in dealing with each seed size is presented in Table 1. Chickadees ate the 319 320 THE WILSON BULLETIN Septcml)er 1967 Vol. 79, No. .3 Mean Times Table 1 FOR Chickadees and Titmice to Small Sunflower Seeds (in Husk and Eat Seconds ) Large and Species Seed size Husk Eat Husk plus Eat Chickadees large 14.6 69.0 76.4 Chickadees small 10.1 29.6 39.7 Titmice large 5.3 28.5 33.8 Titmice small 3.3 23.3 26.9 smaller seeds faster than the larger [P < 0.05. Student’s test ) and titmice husked the smaller seeds faster than the larger ( P < 0.05, Student’s test I . A comparison of husking, eating, and husking plus eating in both species shows that titmice were significantly faster with both seed types, except in eating the small seeds. Effect of temperature on size preference. — The observations on size choice were divided into two periods based on temperature ( 32 L and below, “cold,” and above 32 L, “warm” ) . Chickadees showed a very strong preference for small seeds on warm days and a marked shift in preference toward large seeds on cold days ( P < 0.0001, Chi Square for contingency I . The titmice always preferred large seeds and chose a slightly greater proportion of them on the warm days than on the cold days I P < 0.05, Chi Square for contingency) (Table 2). DISCUSSION In general, the titmice preferred larger seeds than the chickadees. This supports the original hypothesis; namely, that the larger-billed titmice would ])refer larger seeds and the smaller-billed chickadees would prefer smaller seeds. The titmice were more efficient than the chickadees as judged by the time spent husking plus eating both seed sizes, indicating an absolute ad- vantage to a larger bill in utilizing sunflower seeds. Table 2 The Numbej^ of Large and Small Sunflower Seeds Taken by Chickadees and Titmice on Warm and Cold Days Chickadees Titmice Temperature Large Small Large Small Above 32 F 98 346 301 83 32 F and below* 333 352 785 331 Total 431 698 1,086 - 414 SEED-SIZE PREFERENCE IN TITMICE 321 Mytoi. aiul Kickon The change in size preference by the chickadees on cold days might he explained by the increased amount of food obtained per unit effort when large seeds were taken. Although there was slightly more than twice as much endoplasm in a large sunflower seed as in a small one, it also took the chickadee approximately twice as long to husk and eat a large seed as a small one (Table 1). However, the chickadee had to make two trips to the feeder to obtain the same amount of food when it chose small seeds, and it would he more efficient for the chickadees to take the large seeds. Because of the stress of cold placed on the chickadees in the cold weather ( Brewer, 1963 ) and the need for greater energy on cold days, it follows that chickadees would benefit by being more efficient on cold days. Thus, it seems that there are two mechanisms in operation. First the chickadee shows a natural preference for smaller seeds; and, second, this preference is modified under conditions of cold stress when efficiency is of overriding importance. SUMMARY Field experiments on seed-size ehoiee revealed that Tufted Titmice preferred larger sunflower seeds and Carolina Chickadees preferred smaller sunflower seeds as pre- dicted from their difference in hill size. However, the chickadees showed a marked shift toward large seeds when the temperature was 32 F or below. Two mechanisms seemed to operate in this species: 1) a natural preference for small seeds, and 2) the modification of this preference toward one of increased efficiency under cold stress. ACKNOWLEDGAIENTS We are grateful to Edward C. Keller for his help with the statistical analyses, and to him and Millicent S. Ficken for their critical reading of the manuscript. This research was supported hy the National Science Foundation (GB-891 and GB-3226). LITERATURE CITED Betts, \I. NI. 1955 The food of titmice in an oak woodland. J. Animal Ecol., 24:282-323. Brewer, R. 1963 Ecological and reproductive relationships of Black-capped and Carolina Chickadees. Auk, 80:9-47. Hinde, R. a. 1959 Behaviour and speciation in birds and lower vertebrates. Biol. Rev., 34:85-128. Lack, 1). 1947 Darwin’s finches. Cambridge Univ. Press, Cambridge. Morris, I). 1955 The seed preferences of certain finches under controlled conditions. Aricul- tural Mag., 61:271-287. Snow, D. W, 1954 The habitats of Eurasian tits ( Parus spp. ) . Ibis, 96:565-585. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MARYLAND, COLLEGE PARK, MARY- LAND (PRESENT ADDRESS ( R.W.F. ) . UNIVERSITY OF WISCONSIN-MIIAVAUKEE, MILWAUKEE, WISCONSIN). 3 MARCH 1966. ADDITIONAT. OP>SEKVATIONS ON THE STRUCTURE OF UNUSUAI. FEATHER TIPS Alan H. Bkusit IN spile of their obvious importance in almost all phases of avian biology there are still some asjjects of feathers which are poorly known structur- ally. Accordingly, interest in feather morphology persists among ornitholo- gists ( Portmann, 1963 ) . One such area is the internal morphology of tipped elements which occur on feathers of widely diverse taxonomic groups of birds. Recently, for example, the relationship between pigment and feather tip structure has been described in the Cedar Waxwing ( Bornbycilla cedro- rum] (Brush and Allen, 1963), and in the Scaled Cuckoo { Lepido }>:r animus cumin^i) (Brush, 1965). These investigations have indicated the existence of at least two different structural arrangements involved in the formation of such tips. The first, as found in the waxwing, involves the expansion and flattening of the terminal portion of the rachis. In these structures, the structured medulla lies between unequal thicknesses of the surrounding amorphous cortex. The carotenoid pigment is deposited in the cortex. This uneven cover produces the shiny ventral and duller dorsal aspect character- istic of these tips. The second mechanism, as found in the cuckoo, involves the fusion of the rachis with a number of barbs and minor structural ele- ments. This produces a flattened structure with an internally segmented appearance. Individual segments are compressed laterally and may fuse. There is a heavy pigment ( melanin ) concentration in the center of the tip. There are no external differences in the appearance of the surfaces in such tips. The latter mechanism is more common than the former. Indeed, Chandler (1916) suggested that the structure in the waxwing may be unique among birds. It should also he noted that there is a weak correlation of one mecha- nism with melanin pigments and of the other with carotenoids. In no case described thus far is the functional aspect of these structures completely clear. It was the objective of the study reported here to investigate further the structural and chemical nature of various unique feather tips not reported previously. Included in this investigation were feathers from the Curl-crested Aracari ( Pteroglossiis beauharnaesii ) ( family Ramphastidae ) . and several species of the genus Rallus. METHODS AND RESULTS Pigmentation. — The coloration of the tips in all feathers described in this study was due to melanin pigments. The techniques of bleaching with hydro- 322 Alan H. Brush FEATHER TIP STRUCTURE 323 RqIIus elegons Fig. 1. Tipped feather from the crest of the Curl-crested Aragari { Pteroglossus heaiiharnaesii) . Actual length, 20 mm. Tipped feathers from several Rails. Lengths range from 7.2 mm iR. elegons) to 1.1 mm iR. longirostris) . gen peroxide or peracetic acid and reduction of ammonical silver nitrate were used for melanin analysis (Brush, 1965). Structure. — Whole mounts of feathers were made with Canada halsam ( Fig. 1 ) . Cross-sections were made by mounting tissues in methacrylate and section- ing with a glass knife. Several other techniques which included embedding and sectioning in high melting point paraffin (Dr. P. Stetlenheim. pers. comm.), diethylene glycol distearate, or gelatin were tried, hut met with less success. 324 TIIK WILSON BULl.KTIiN ScptcmlxT 1967 \ ul. 79. N... Fig. 2. Cross-section of feather tip from R. indicus. Note relatively unstructured cortical layer. Ill cross-section the tips of the feathers from the crest of the Curl-crested Aracari appeared similar in morphology to that of the Scaled Cuckoo, in that the tip consisted of an internal medullary area which was heavily pig- mented and which was surrounded by a relatively clear cortex. The highly keratinaceous cortex when seen in serial section supports the notion that it has developed from the fusion of several barbs or barb-like structures. Cross-sections of the feather tips from members of the genus Rallus ( R. ac/uaticus, R. elec^ans. and R. lon^iroslris I presented a pattern quite different from that described above. Tips generally tended to be oval rather than flattened and the internal structure (Fig. 2) suggested that only the rachis was involved in the formation of the tip. The tips of the rail feathers lacked the regular, repetitive structural units characteristic of the Pteroglossus tip. The cuticle appeared unsegmented and the inner pulp contained pigment FEATHER TIP STRUCTURE 325 Alan H. Bnish X-Section of Tip f Lepidoqrammus. Pteroqlossus X-Section of C£3 Rach i s and Barbs C®3 ® ® Fig. 3. Suggested relationships among various tipped feathers. The generalized structure of the rachis can he modified to produce tip structures of divergent morphology. granules and various structural elements characteristic of the rachis. Gen- erally, the tips of Rallus were considerably smaller than any of those investi- gated previously. Feathers similar to those in Rallus were also observed on the forehead of the Pied-billed Grebe { Podilymbus podiceps). DISCUSSION As was suggested earlier, at least two mechanisms may exist for the pro- duction of feather tips. Both types are found in widely divergent taxonomic groups and are therefore the result of convergent evolution within these group. Bonhote (1912) observed that the external structure of the feather tip of the rails resembled those of the waxwing. There are. however, differences. 1 he waxwing tip contains carotenoid rather than melanin pigments and it is 326 THE WILSON BULLETIN Septi-inluM- iy()T Vol. 79, No. 3 considerably more flattened than is the rail tip. Carotenoid pigments are deposited in the relatively clear, unstructured cortex while the melanin pig- ment of the rails is deposited in the medullular areas. In spite of these dif- ferences in the location and type of pigments it appears the basic internal structure is similar in both forms. Therefore the waxwing tip can no longer he considered an entirely unique structure. The function of the feather tips described here is still somewhat obscure. Bonhote suggested that the tipped feathers on the head of the rails may serve a protective function in preventing the abrasion of the feathers as the bird moved through the underbrush. The small size and the fact that relatively few feathers actually have tips cast some doubt on this interpretation. How- ever, the similarity of the size, structure, and location of the tipped feathers in the rails and the grebe may be a convergent response to similar selective pressures. The larger tips of the aragari and cuckoo may serve a signal func- tion. However, they are dark and their visibility, and thus potential use- fulness, in the animal’s habitat is unknown. The absence of a satisfactory functional analysis of tbe tips in the waxwings has been discussed ( Brush and Allen, 1962) . Regardless of differences in their internal structure and function, the feather tips presumably share a common origin ( Lig. 3 ) . The structural ele- ments of the tips are derived ultimately from modifications of structural elements already present in feathers. The formation of feathers may be one of the most complex developmental processes in vertebrate skin as it involves the alignment of rows of cells which form the shaft, barbs, and barbules 1 Spearman, 1966). Additional studies on the control of development of these structures promise to be of interest. ACKNOWLEDGMENTS I thank Avis Sylvia for technical assistance and Dr. Allen Wachtel for the generous loan of equipment. This investigation was supported in part by a grant from the University of Connecticut Research Foundation. LITERATURE CITED Bonhote, J, L. 1912 On a peculiar type of feather in the Water-rail. Brit. Birds, 5:42-44. BFtusH, A. H. 1965 The structure and pigmentation of the feather tips of the Scaled Cuckoo ( Lepidogrammus cumingi). Auk, 82:155-160. Bhusii, a. H., and K. Allen 1963 Astaxanthin in the Cedar Waxwing. Science, 142:47-48. Chandler, A. C. 1916 A study of the structure of feathers, with reference to their taxonomic sig- nificance. Univ. California Publ. Zook, 13:243-446. FEATHER TIP STRUCTURE 327 Alan H. Brush PoHTMANN, A. 1%3 Die Vogelfeder als inurphologisclies I^rohlem. Verhandl. Nalitrf. Ges. Basel, 74:106-132. Spearman, R. I. C. 1966 The keratinization of epidermal scales, feathers and hair. Biol. Rev., 41:59-96. DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, UNIVERSITY OF CONNECTICUT, STORRS, CONNECTICUT, 25 APRIL 1966. NEW LIEE MEMBER Dr. William A. Carter, Associate Pro- fessor of Biology at East Central State College, Ada, Oklahoma, is a new Life Member of The Wilson Ornithological So- ciety. Dr. Carter holds a bachelor’s de- gree from East Central State, and a Ph.D. from Oklahoma State University. His doctoral research involved an ecological study of the nesting birds of the McCur- tain Game Preserve. Some of the results of this project appear in the paper on page 259 of this issue of The Bulletin. He is a member of the AOU, Cooper Society, National Audubon Society, Okla- homa Ornithological Society, American Society of Ichthyologists and Herpetolo- gists, as well as other scientific societies. His principal ornithological interests are in the fields of ecology and niche posi- tions, and bird populations, and he has pul)lished several papers in this field, as well as in the field of herpetology. THE IXFEUENCE OF VOCAL BEHAVIOR ON THE PERFORMER'S TESTICI EAR ACTIVITY IN BUDGERIGARS ( MEJAJPSITTACI S UM)l LATi S ) B\rbara V. Brockway Astrikinji feature of an aviary containing the Budgerigar is the seem- ingly constant ‘'chatter'' or "singing" which results from many indi- viduals simultaneously performing Loud and Soft Warble. Both of these ‘‘songs'' ( sensu Borror. 19611 contain several components performed in varving sequences and are the most elaborate of all Budgerigar vocal patterns I for description of all vocalizations, see Brockway. 1964a and 196-46 I . It is common avicultural knowledge that Budgerigars ( commonly called parakeets in the U.S.A. ) typically do not breed unless pairs can hear each other. This has been experimentally substantiated by Ficken et al. 1 1960) and Brockwav 1 1964c i . W hen males are able to hear others, individuals commonly spend up to one-quarter of their waking hours performing Loud W arble as a result of inductive mimesis ( Brockway, 19646 and unpublished data ) . If permitted to interact with a homo- or heterosexual partner, such males will also perform three precopulatory vocalizations, namely Soft Warble. Tuks, and W hedelees. These three vocal patterns function in part to stimulate ovarian activity ( Brockway, 1965 ) . Even without a sexual partner, males that are able to hear others maintain their year-long typically high levels of testicular activity and can be milked for motile, unstainable spermatozoa (see Table 1). Males, which are prevented from hearing each other, perform such vocalizations as alarm and location calls in quantities similar to those of males able to hear others. Such isolated males, however, perform significantly little or no Loud W arble or precopulatory sounds, cannot be milked for seminal fluid containing spermatozoa, and possess markedly regressed testes and vasa deferentia after 3 to 5 weeks of isolation ( Brockway, 1964c and Ficken et al.. 1960 ) . To investigate whether it is the hearing of Loud W arble with or without precopulatory vocalizations performed bv other males and/or some factor arising from the performance of these by an individual which stimulates a male's testicular activity, the gonadal conditions of both “devocalized" and sham-operated males able to hear others was studied. MATERIALS AND METHODS Seven males were rendered incapable of performing recognizable budgeri- gar sounds by surgically severing their right and left sternotrachialis muscles and removing a half-inch segment from both the right and left hypoglossal 328 Harhara F. Brockway VOCAL BEHAVIOR AND TESTICULAR ACTIVITY 329 nerves adjacent to these muscles. Such “devocalized’’ birds utter only hoarse mono- and polysyllabic “burp’' or “keek” sounds. Sham operation on seven control birds involved procedures identical to those used in “devocalization except the sternotrachialis muscle and hypoglossal nerves were only gently touched with forceps. For further control, “devocalization” surgery was performed on only the left side of two additional males. At the time of surgery (day 0) and at 21 and 36 days later, all of the sexually mature 9 month old virgin males used for this study were milked for spermatozoa and laparotomized so that their reproductive organs could be measured. Following the initial surgery, all males were returned to the aviary environment in which they had previously lived and where they could hear all budgerigar sounds including the almost continual daily Loud Warble performed by some 60 males in stock cages and 14 males of pairs in breeding cages. Control and experimental males were placed in adjacent cages so that both groups could hear the abnormal utterances of “devocalized” males. The sounds produced by each “devocalized” or control male were qualitatively and quantitatively recorded during 45 minute observation periods three to six times a week for 35 days. Maintenance (e.g. ; preening, eating, etc.) and sexual behavior were noted during these observations and also at other times during the study. French’s Parakeet Seed, French’s Conditioning Food, cuttlebone, quartz gravel, and water were provided ad libitum. RESULTS AND DISCUSSION After three days, all control birds resumed their typical performance of budgerigar sounds including large quantities of Loud Warble. The seven “devocalized” males continued to perform only low-pitched “burp” or higher- pitched “keek” sounds throughout the study. The results, presented in Table 2, show that high levels of testicular activity are maintained only by males performing typical budgerigar sounds. Hearing the vocalizations of other males is not sufficient. No finer correlation was found between the recorded amounts of any vocalization performed by an individual and the size of his reproductive organs within either the control or experimental groups. That surgical trauma did not produce the decreased testicular activity of the “devocalized” males can be seen from data on controls, especially those “half- devocalized” birds which showed no significant changes in testicular ac- tivity and performed Loud Warble and all typical adult non-sexual vocaliza- tions. “Devocalized birds experience two phenomena which control birds do not. I hey suddenh (ll are unal)le to perform normal species-t\ pical vocal 330 Till-; WILSON BLLLE'IIN H ^ z ii < c/3 H ^ 1, i* ^il III III 1^ ^ ir il > = = ■2 s- r? '£ £ li II if Sei»teiiil)cr 1907 Vol. 79, No. 3 Table 2 Stimulation of Testicular Activity by Factors Involved in Performing Vocal Behavior.’ Barliara F. Biockway VOCAL BEHAVIOR AND TESTICULAR ACTIVITY C/5 O ^ N ^ p « 2 !Ll _ 5 c c a 1'^ ^ o .G <2 p (u p S 05+3 >:2 |§ OJ H lO o o O (M o o V A lO o o o cs C5 O V A CO o^ o d i-H r-H CO d d LO o o O CM d d V A ON VO CM CO CM ON P I— H LO o o O CM d d V A r-H CM CM CO CO vd V o o P rH id d ^ A 8 I— I O LO LO vd L-’ ~o ^ * OJ >-i ' * ;o a > * 9 S ^ S 33 2 » ^ C 7. E S rtr-5 W) !m c 0; c4 a ■I-S ? 01 c/, ^ .S3 M'S _o;-p u ^ OJ a o oq 1 O A o 'O QJ fli A- P D ^ bC-G P03 a p LO rH O O o o o V LO CM rH o VO r-H O d d d ' ' V Hf LO VO NO O r-H d d V LO CO o VO r-H o CM d d V LO r-H o CM o o cd r-H d V 03 C3 l; S-i N O a O G o S H G 1) JG C CC G, bc I p ^ p ^ ^5 c a a 33 a cj O OJ a ^ O 2 P rt SQ 'S s .9 C CS 0; a iP cS a p « S J d d (U C3 S I tDa P as 3 > P ^ o r > B En 331 square and analysis of variance tests. ** The day of surgery, 1 day before the start of this study. *** Comparisons between values for day 0 and 36. **** These values are not included in the statistical comparisons between devocalized and control sham-operated males. 332 TIIK WJLSON BULI;ET1^ il.iT 1907 ■9, No. ;i ScpIlMlI \ ol. 7 i)ehavior and (2) produce sounds dissimilar to any they had ])reviously made, rhese experiences cannot, as yet, be separated from each other. Furthermore either, in itself, might he a stress sufficient to prompt the decreased testicular activity observed for “devocalized” males. This possibility might be mini- mized by “devocalizing” young birds well before they ordinarily would perform the elaborate Loud Warble and precopulatory vocalizations and studying their subsequent gonadal development. High blood levels of adrenal hormones (e.g., corticosteroids) are commonly associated with stress, re- sulting in gonadal regression. Unfortunately, methods do not yet exist for measuring these levels in the limited blood volumes of small birds. Accord- ingly, birds were examined for other, grosser indications of stress. The following data suggest that the “devocalized” males were not undergoing reactions to stress as a result of their inability to perform anything but ab- normal vocalizations: (1) the amounts of food and water they consumed did not differ from the amounts consumed by the control group; (2) their body weights were insignificantly different from those of the controls; (3) they showed no abnormal persistently ruffled or sleeked body feather pos- tures; (4) they performed no aberrant visible behavior patterns; (5) some males performed visible precopulatory displays oriented to other males ( a typical event among unisexually caged Budgerigars) ; and (6) 70 days after devocalization, their reproductive organs were in the same conditions as noted 35 days after “devocalization.” Of all the vocalizations in the repertoire of Melopsktacus, only Loud Warble, Soft Warble, Tuks, and Whedelees appear to be associated with gonadal activity ( Brockway, 1964c ) . Not all control birds were heard to perform the three precopulatory vocalizations and yet all non-performers showed spermatozoa when milked and there was no distinguishable difference in their testes and vasa deferentia measurements and those of control males which did perform these vocalizations. Furthermore, the circumstances dur- ing which these three vocalizations are predominantly performed, i.e., pre- copulatory interactions, are not necessary for the full gonadal development or function of either sex ( Brockway, 1962 and 1965 ) . These observations strongly suggest that the performance of Loud Warble promotes the main- tenance of high levels of testicular activity. Whilst hearing the vocalizations of other males appears insufficient, in itself, to maintain full testicular activity, a male’s performance of Loud Warble stimulates and in turn is stimulated by the Loud Warble of others. By so stimulating individual vocal performances, social vocal activity would play an important role in promoting the testicular activity of the flock. This would also help to explain why a male which is isolated from the sounds of others typically shows low levels of androgen secretion and spermatogenesis Ilarl.ata F. Hiockwav VOCAL BEHAVIOR AND TESTICULAR ACTIVITY 333 and why pairs of Budgerigars isolated from the sounds of others typically fail to breed. Other known instances in which the performance of specific behavior patterns stimulates or is required for anterior pituitary gonadotrophin or gonadal hormone secretions in the perjonner seems mainly restricted to parental behaviors (for review, see Lehrman, 1961). Other known examples of a behavior’s stimulation of anterior pituitary or gonadal activity involve sexual or courtship interactions between 2 individuals. In these, the behavior of one influences the endocrine activity of the other (e.g., Brockway, 1965; Burger, 1942 and 1953; Polikarpova, 1940; Matthews, 1939; Shoemaker, 1939; Lehrman et al., 1961, and Warren and Hinde, 1961). Thus, this study on Budgerigars may be the first experiment indicating a self-stimulation of an individual’s gonadotrophin secretion or gonadal activity by the perform- ance of a non-parental behavior. It would be interesting to know if any "‘songs” of other avian species might have, in part, a similar function. Another point of interest stems from the ethological designation of all vocal behaviors as displays. Displays are commonly regarded as those species-typical behavior patterns primarily functioning to provide signals which alter the activity of the nervous or endocrine systems of other indi- viduals (Tinbergen, 1964; and Hinde and Tinbergen, 1958). Budgerigars may possess at least one display which functions not only to stimulate other males to perform it but also stimulates the endocrine activity of the performer. SUMMARY Data on surgically “devocalized’' and sham-operated controls indicates that the gonadal activity of male Budgerigars may he stimulated as a result of their performance of vocal display (s) rather than as a result of hearing such behavior hy others. This may he the first demonstration of the self-stimulation of an individual’s endocrine ac- tivity hy his performance of a species-typical behavior which involves gonadotrophins and non-parental behavior. Since vocalizations are ethologically regarded as displays, the current thinking about the functions of displays may need expansion, ACKNOWLEDGMENTS This study was supported hy Researeh Grant CB-3191 from the National Science Foundation and the generous provision of seed hy the R. T. French Company of Rochester, N.Y. The author also wishes to thank Dr. Alan P. Brockway and Mrs. Marilyn Goodrich for their invaluable help during this study. LITERATURE CITED Bohhoh, 1). J. 1961 Songs of finches ( Fringillidae t of eastern North America. Ohio Jour. Sci., 61:161-174. IhtOCKWAY, B. F. 1962 The effects of nest-entrance, positions and male vocalizations on reproduction in Budgerigars. Living Bird, 1 :93-101. 334 THE WILSON RULLETm Soptenil)er 1967 Vol. 79, No. .3 l%4r/ Etholojiical studies of the Ifudgerigar ( Melopsittacus andulatus) : non- reproduct ive heliavior. Behaviour, 22:193-222. VXAh Etliologieal studies of the Budgerigar (Melopsittacus undulatus) : reproduc- tive heliavior. Behaviour, 23:294 324. 1964c Social influences on reproductive physiology and ethology of Budgerigars i Melopsittacus undulatus) . Animal Behaviour, 12:493-501. 1965 Stimulation of ovarian development and egg laying hy male courtship vocali- tion in Budgerigars (Melopsittacus undulatus). Aninad Behaviour, 13: 575 578. Buhgkk, .1. W. 1942 The influence of some external factors on the ovarian cycle of the female starling. Anat. Rec., 84:518. 1953 The effect of photic and psychic stimuli on the reproductive cycle of the male starling, Sturnus vulgaris. J. Exp. Zool., 124:227-239. EiCKr:N, R. W., A. van Tikniioven, M. S. Fk.ken, and Y. C. Sibley 1960 Effect of visual and vocal stimuli on breeding in the Budgerigar ( Melopsitacus undulatus). Animal Rc/icc/oi/r, 8:104-106. Hinde, R. a., and N. Tinbergen 1958 The comparative study of species-specific behavior. In Behavior and Evolu- tion (A. Roe and G. G. Simpson, ed.), Yale Ihiiv. Press, New Haven :251-268. Leiikman, I). S. 1961 Gonadal hormones and parental behavior in infrahuman vertebrates. In Sex and Internal Secretion; Vol. II (W. C. Young, ed.), Williams and Wilkins Co., Baltimore: 1268 1382. Leiihman, I). S., P. N. Brody, and R. P. Wortis 1961 The presence of the mate and of nesting material as stimuli for the develop- ment of incubation behavior and for gonadotropin secretion in the Ring Dove { Streptopelia risoria) . Endocrinology, 68:507-516. Lr, .1. C. R. 1964 Statistical Inference: Vol. I. Edwards Bros., Ann Arbor, Michigan. Matthews, L. 1939 Visual stimulation and ovulation in pigeons. Proc. Royal Soc., 126B :557-560. PoLIKARPOVA, E. 1940 Influence of external factors upon the development of the sexual gland of the sparrow. C. R. Acad. Sci. U.R.S.S., 26:91-95. Shoemaker, H. H. 1939 Effect of testosterone propionate on behavior of the female canary. Proc. Soc. Exp. Biol. N.Y., 41:299-302. Tinbergen, N. 1964 The evolution of signaling devices. In Social Behavior and Organization Among Vertebrates (W. Etkin, ed.), Univ. Chicago Press, Chicago :206-230. VAN Tienhoven, a., H. C. Thomas, and L. J. Dreesen 1956 The effect of sulfamethazine feeding on the thyroids, combs, and testes of single combed white leghorn cockerels. Poultry Sci., 35:179-191. Warren, R. P., and R. A. Hinde 1961 Does the male stimulate oestrogen secretion in female canaries? Science, 133:1354-1355. DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, THE OHIO STATE UNIVERSITY, COLUMBUS, OHIO, 30 JUNE 1966. AN IMPROVED CAGE DESIGN FOR EXPERIMENTATION WITH PASSERIEORM BIRDS Elden W. Martin ONE of the essential laboratory items needed for experimental studies of the bioenergetics of birds in captivity is a properly designed cage. Cages used at the University of Illinois were first constructed entirely of hardware cloth ( Kendeigh, 1949 ) , but many improvements were made in later years. In the author’s nutritional studies with the Tree Sparrow {Spizella arborea) , begun in 1962, several new modifications were incorporated in the cages in the interest of decreasing food loss, lessening the chance for birds to escape, and increasing the efficiency of separation of feed from accumulated feces. Since there are frequent inquiries concerning these cages, it seemed desirable to publish a set of directions for their construction. DETAILS OF CONSTRUCTION AND DISCUSSION The cage proper measures 31 X 16 X 31 cm, and is built with galvanized sheet-metal walls which extend above the level of the perch (Fig. 1). The upper two inches of the walls and the top of the cage are of one-half inch mesh welded hardware cloth which permits adequate light entry and air circulation. The vertically sliding door reduces chances of escape whenever the birds are handled. The cage, as illustrated, is equipped for recording of bird activity. The switch assembly ( S in Fig. 1) on top of the cage, similar to that used on the older-type cages, consists of an adjustable spring-assisted microswitch that supports a hooked center rod to which the perch and move- able cage bottom are attached. The switch closes whenever the bird jumps onto or off of the perch or cage bottom. The moveable cage bottom is suspended approximately one inch above the excrement-pan floor. The cage is easily modified to a non-activity type. For that purpose, a one-inch mesh screen bottom (less center rod) is supported by four one- eighth inch bolts arranged two on a side about one inch above the floor pan. A centrally positioned one-half inch wooden dowel perch, with ends tooled to fit one-quarter inch holes in the cage sides replaces the rod perch. A handle formed from number nine galvanized wire and attached to the top of the cage aids in the cleaning operations. The simple conversion feature of this type of cage reduces the number of cages necessary for the conduct of studies alternately considering or ignoring activity. Detailed construction plans for the cage and its attachments are shown in Figure 2. The floor pan I Fig. 1 ) consists of a simple one-half inch deep pan with rolled edges except at the open end which extends about two inches in front of the cage to collect any accidentally spilled feed. 335 336 VUE WILSON BULLKTIN S<-ptcml)t‘r 1967 \ ol. 79, No. 3 Fig. 1. A: Cut-away view from the riglit side of experimental eage showing relative positions of feeder (F) and water eup (W), and pereh-liottom unit hooked to aetivity switch assembly (S). B: ('mneral view of eage as placed on the excrement jian, showing feeder attachment and vertically sliding door. The placement of the food source outside the cage prevents, to a large extent, scattering of feed inside the cage. The birds quickly learn to reach through the one-inch diameter hole to feed, being encouraged to do so by purposeful displacement of some feed through the hole onto the cage floor when they are first introduced. Part (Fig. 2 and Fig. lA), in addition to forming the front of the feeder, includes an apron portion which serves j)artially to separate the feeding area and storage area, thus preventing gross scattering of feed. This also serves to encourage the birds to eat most of the feed in the feeding area before fresh unpicked feed falls from the storage area. When food is offered in the form of finely ground mash, it is advisable to release any compressed mash by passing a spatula or similar tool down through the storage area at least once a day so that the feeding area constantly contains food. The portion of the food hopper immediately outside the feeder hole is covered by a fitted lucite strip so that the feeding area is well lighted. In actual use, the cage is usually cleaned at three-day intervals. After cleaning, a labeled, pre-weighed sheet of aluminum foil (both Reynolds Wrap and Kaiser Foil in 12-inch widths have been used at one time or another) is placed under the cage proper so that the floor pan is lined. At the end of the three-day interval, the accumulated excreta is separated from any feed CAGE DESIGN 337 Fig. 2. Scale drawing of composite parts of experimental cage. W — Back side of cage with watering hole over which waterer (Wt>) fastens on clips D. Points e and f are soldered points of attachment for perch (P). W;i is cage side of waterer. F — Front side of cage with feeding hole and door opening. Feeder (Fid has a top front (F;d which attaches at common letter points (a to a, 1) to h, etc.) and a bottom front (F4) which provides extensions (c and d) to hold feeder to the cage hy hooking on clips 1). Sliding door (C) runs in cdiannels formed hy bending strip E double. A & B — identical side pieces for cage. Wire Top — piece cut from V2 inch mesh hardware cloth; to he soldered to main c-age frame formed hy soldering W, F, A, and B. Dotted lines represent break-points for 90-degree bends except for piece E which reipures a bend of about 170 degrees. 338 THE WILSON BULLETIN Soptcmlier 1967 Vol. 79, No. 3 (finely ground I which may have been spilled, with the aid of a draftsman’s brush and a one-sixteenth inch wire screen sieve. The excreta is gathered into the bottom foil, which is then folded loosely (to j^revent loss) and oven- dried. Other investigators that have used the cage have not employed the foil liner, simply allowing excreta to accumulate on the bottom pan. However, the use of foil eliminates the necessity of scraping, and thus fragmenting the excrement. When foil is used, granules of feed readily tap free from the polished surface at the time of cage-cleaning whereas scraping from the excrement pan requires drying of spilled (and uneaten) feed and excrement together, followed by screening and mechanical agitation to dislodge food particles. The latter process would seem to encourage further fragmentation of the excrement with a resultant loss of part of the excrement quantity through the sieve. Where metabolism or bioenergetics studies are in pro- gress, this loss of raw material may result in underestimation of excrement quantity produced, and overestimation of feed not eaten. SUMMARY Several new ideas were incorporated in the design of an experimental cage for passeriform birds. Detailed construction plans are included and some of the design features are discussed. Suggestions for routine application procedures of the cage are offered including the use of aluminum foil as a disposable medium to aid in (juantitative excrement collection and handling. ACKNOWLEDGMENTS I wish to thank August Kosowski for his timely design suggestions and for his skill and care employed in the actual construction of the cages. 1 am indebted to Dr. S. Charles Kendeigh for his encouragement in this endeavor and for his criticism of the manuscript. The project was supported in part by National Science Foundation grants awarded to Dr. Kendeigh. The paper was based on part of a doctoral thesis in the Department of Zoology, University of Illinois, Urhana, Illinois. LITERATURE CITED Kendeigh, S. Charles 1949 Effect of temperature and season on energy resources of the English Sparrow. Auk, 66:113-127. DEPARTMENT OF BIOLOGY, BOWLING GREEN STATE UNIVERSITY, BOWLING GREEN, OHIO, 43402, 25 January 1966. GENERAL NOTES Flightless Green-winged Teal in southeast Missouri. — On 25 September 1963, four adult female Green-winged Teal i Anas carolinensis) were caught in a night drive- trapping operation on the Duck Creek Wildlife Management Area near Puxico, in southeast Missouri. All had recently molted their wing feathers and were flightless. New flight feathers were at various stages of development: in three birds the longest primaries (the ninth primary in each case) were 70-75 mm long; in one bird the longest primary was 48 mm long. The flight feathers all had soft, blood-filled shafts. In con- trast, the full-grown ninth primary is about 120 mm long in adult females, and feather shafts are hard and translucent. This information is reported here because there appear to he no previous observations of flightless Green-winged Teal in Missouri or in other areas so far south of the breeding grounds. No further drive-trapping has been done at Duck Creek so it is not known if such molting occurs regularly here. — John P. Rogers, University of Missouri, Gaylord Memorial Laboratory, Puxico, Missouri, 2 August 1966. Disgorging of food by Wood Ducks. — Malone (1966. Wilson Bull., 78:227-228) reported regurgitation of Chara by Mallards (Anas platyrhynchos) about 45 minutes after ingestion. The Chara was disgorged in loosely compacted balls, each ball being about one inch in diameter. Malone postulated that disgorging resulted from overeating. No comparison was made of the moisture content of the food when eaten and when disgorged. It is the purpose of this note to report somewhat similar behavior by the Wood Duck (Aixsponsa). In Ohio during 1955-57, I trapped and banded some 600 Wood Ducks. Traps were placed at the water’s edge, with the corn on dry soil at the rear of the traps and the funnel entrance of the traps in shallow water. The birds could thus drink water as they fed on the dry corn. An al)undance of corn was kept in the traps, and Wood Ducks regularly entered the traps and ate to the limit of their capacities. Crops and gullets were often crammed so full they literally could not hold another kernel. Feeding was completed in a few minutes. These corn-filled ducks were sometimes kept overnight in burlap bags before work with them could be completed, and corn was often found loose in the bags. In one bag holding 12 ducks, 264 kernels were found, for an average of 22 kernels per bird. The corn was necessarily disgorged by the ducks. Even after such a night in confine- ment, the ducks often had well-filled crops and gullets. The corn presumably did not move through the alimentary tracts sufficiently rapidly to keep pace with the increase in volume resulting from imbibition. In the morning, a total of 190 kernels of corn was removed from the digestive tract of one of these corn-filled ducks, 136 kernels coming from the crop and gullet. In a supplementary test, 158 (136 plus 22) kernels of corn were soaked in water overnight; the increase in volume was such that 46 kernels were displaced. With 22 kernels disgorged per bird and tbe crops and gullets being al)out ecjually well-filled in the morning as the preceding evening, approximately 24 kernels moved from the crop farther into tbe digestive tracts. This ability to disgorge food in excess of capacity may operate to avert rupture of tbe crop wall. If tbe crop is filled to capacity, increase in volume of crop contents i)resumably would be hazardous to the crop wall. Malone ( oj). cit.) commented on tbe possibility of regurgitation of food by ducks o{)crating in the diss<‘mination of j)lant pro{)agules. In this case with the Wood Ducks, :v,v) 340 TWK WILSON BULLETIN S(*pt<‘ml)er 1967 Vol. 79, No. .1 tlu* (lisgorfiino; of food can he .seen as an effective means for transporting vialile propaguh's from the birds’ feeding places to their roosting places. Tlu* observations reported in this note wert* made when I was a Research Fellow of the Ohio (iooiieralive Wildlife Kes<*arch Unit. — Paul A. Stkwaht, Entomology Research Dirision, Agrirnltural Research Service, USDA, Oxford, North Carolina, 13 July 1966. |{ul‘f-hreastetl Sandpiper in northwestern Ohio. — On 11 .June 1%6 I was partici- pating in a state-wid(* breeding bird census. I, accompanied by five of my students, ran a 25-mile transect stopping to make a 3-minute observation every half mile. Approximately half of my transect was in Hardin County and the remainder in Wyandot County. At 10:00 AM we were standing outside the car beside a plowed field on Wyandot County Road 294, five miles west of Harpster, Ohio. While I was listening for bird songs from a nearby woodlot my attention was drawn to a sandpiper moving among the clods in the adjacent field. It was a Ruff-hreasted Sandpiper iTryngites suhruficoHis) . Within a few minutes we located six other individuals. They were exceedingly tame and fed over the plowed field independently. On several occasions they approached within 30 feet and we observed them for 20 minutes. At the end of that time the birds got up as one and flew off to the east. The only previous spring record of this species in Ohio is given as 6 May 1923 hy Borror (1950. Ohio Jour. Sci., 50:1-32). Although the spring record of the Buff-hreasted Sandpiper in Ohio is unusual, the date is not. Oring ( 1%6. Wi/.son Bull., 78:173) had this species in Oklahoma on 3 .June. — Richard S. Phillips, 834 Liberty Street, Findlay, Ohio, 23 July 1966. Egg teeth and hatching methods of the Long-hilled Curlew. — Recent discussions on egg teeth (Wetherhee, 1959. Bird-Banding, 30:119-121; Clark, 1961. Wilson Bull., 73:268-278; Parkes and Clark, 1964. Wilson Bull., 76:147-154) stress the paucity of information on Scolopacidae, so some recent observations on three hand-reared Long- hilled Curlews iNumenius americanus) seem pertinent. The set of four eggs was obtained from a nest west of Brigham City, Box Elder Co., Utah on 24 May 1966. Upon pipping, all four chicks had cream colored egg teeth on both upper and lower hills. The upper tooth was a raised projection 1 mm from the distal tip of the culmen. The lower tooth, on the distal tip of the lower mandible, was smaller, rounded, and barely raised from the surface of the hill. Both teeth were ephemeral and deciduous. In each of the three birds that survived, the lower mandibular teeth were lost on the first day after hatching, and the upper tooth persisted until the second day. The same situation has been described for the American Woodcock (I^hilohela minor) hy Wetherhee and Bartlett (1962. Auk, 79:117), and for the Willet i Catoptrophorus semipalmatus) hy Tomkins (1965. Wilson Bull., 77:151-167). Conflicting data have been reported for other members of the genus Numenius. Willink (cited in Clark, op. cit. ) found only a lower egg tooth in Numenius sp. ; while Parkes and Clark (op. cit.) found only an upper hill tooth in N. tahitiensis. Observations on the hatching method of N. americanus showed that the pip hole was started approximately one third the distance from the large end of the egg. It was progressively enlarged until a circle about 1.5 cm in diameter was formed. The chick then pushed out the large end and emerged hy splitting the remaining shell into three approximately triangular pieces. This method is similar to that utilized hy the September l‘)67 Vol. 79, No. 3 GENERAL NOTES 341 Willet (Tomkins, op. cit.) but different from that of the woodcock (Wetherbee and Bartlett, op. cit.) . I wish to thank K. L. Shirley for cooperation in gathering data and Dr. K. L. Dixon for criticisms of this note. This study was supported by an NDEA Predoctoral Fellow- ship.— Dennis M. Forsythe, Department of Zoology, Utah State University, Logan, Utah, 18 July 1966. Foreign Eggs in Nests of California Gulls. — During a study on the interactions between California (Larus californicus) and Ring-billed gulls (Larus delawarensis) at Miquelon Lake, located at 53°15'N and 112°55'W in Alberta, in 1964 and 1965, three coot, two grebe and two Lesser Scaup (Aythya af finis) eggs were found intact in California Gull nests and were being incubated. Neither coots nor grebes nested on the island or had been seen visiting gull nests. It appears, therefore, that they were ingested whole by the gulls and regurgitated in the nest. On several occasions grebe and duck eggs were observed which were pecked open just outside and over the nest rims. As a rule, when the gulls bring whole eggs back from different localities and regurgitate them outside the nest, they are pecked open and devoured. However, when the eggs are regurgitated within the nest, the drive to incubate these eggs may be stronger than the urge to eat them. Twomey (1948. Condor, 50:97-100) observed California Gulls bringing other birds’ eggs to their nests in Idaho. Sometimes they were carried in the bill, but more often they were swallowed and regurgitated at the nest. The eggs brought were those of Cinnamon Teal (Anas cyanoptera) , Ring-necked Pheasant ( Phasianus colchicus) , American Coot (Fulica americana) , Black-necked Stilt i Himantopus mexicanus) , and Eared Grebe (Podiceps caspicus) . Sugden (1947. Condor, 49:93-96) found Ring-necked Pheasant, Shoveler (Spatula clypeata) and Cinnamon Teal eggs in the California Gull nests in Utah. These data all confirm the suggestion that California gulls swallow eggs whole and regurgitate them later in the nest. — Kees Vermeer, 10177-104 Street, Edmonton, Alberta, 2 August 1966. Bonaparte’s Gull feeding on walnut meat. — The food of Bonaparte’s Gulls (Larus Philadelphia) wintering along the seacoast usually consists of live marine life, mostly taken from the surface of the water (Bent, 1921. U.S. Natl. Mus., Bull., 113:178). During many years of observation of gull concentrations in New Jersey, I have never seen a Bonaparte’s Gull at garbage dumps, pig farms, or the other scavenging areas where the larger gulls congregate. Therefore, I was surprised to find the crop of a Bonaparte’s Gull crammed full of walnut meat. This food was also in the gizzard, whereas no other food was present. The walnut meat was in the form which is commonly used by housewives. The bird, a female in immature plumage, was collected on 22 April 1963 at South Amboy, Monmouth County, New Jersey from a flock of about 200 Bonaparte’s Gulls. This species is common at this time of year at this location. Large numbers are often noted feeding in the tidal rifts in Raritan Bay. I have no idea where this individual could have obtained its unusual meal. The specimen is no. 210605 in the University of Michigan Museum of Zoology. — Robert (7 Froiiling, Howell, Michigan, 6 April 1966. 342 THE WILSON BULLETIN S<*|)teml)er 1967 Vol. 79, No. 3 Predation by the Chuek-v^ill’s-widow upon migrating warblers. — That the Chuck- will’s widow { Caprimiilgus carolinensis) captures birds was known to Audubon <1859. Birds of America, 1:154) who suggested that the species might he “carnivorous.” Suh- secpient reports of bird-capture liave shown Ids supposition to he, to an extent, valid (see e.g.. Bent, 1940. U.S. Natl. Mas. Bull. 176:506.) and have, as Terres 11956. Auk, 73:290) expressed it, indicated that the Chuck-will’s-widow may he “a seasonal if not regular eater of small Iiirds.” Additional evidence of the seasonal aspect of its predatory habits is herewith presented. A Chuck-will's-widow, found dead during the morning of 18 October 1961 in Miami .Shores, Dade County, Florida, was brought to Mrs. Arthur Gasche of that municipality who presented the specimen to me. Wedged tightly into the throat of the caprimulgid, its head well down into the esophagus, was a male Yellowthroat ^Geothlypis trichas) . Death of both birds would seem to have been by suffocation. During preparation of the two as study skins for the University of Miami Research Collections (UMRC), further pertinent information was obtained. The \ ellowthroat, weighing 12.9 grams, contained much suhdermal fat. In its stomach were small insects. The Chuck-will’s-widow, a female, weighed — apart from the fellow- throat — 121.4 grams. It likewise contained considerable fat. In the stomach of the Chuck-will’s-widow was a nearly intact male Cape Warbler i Dendroica striata). Only the warbler’s skull, from which the feathers and skin loosened when the bird was re- moved from the stomach, gave evidence that digestion of it had begun. Remains of this warbler weighed approximately 8.0 grams. (The combined weights of the two warblers, incidentally, are equal to about 17 per cent of the weight of the Chuck-will’s-widow minus its warbler content.) In addition, there were in the stomach two large glassy-winged locusts iStenacris vitreipennis) , these showing but little evidence of digestion. In mid-October, migration down the Florida peninsula is at a peak. That the Chuck- will’s-widow and the Yellowthroat were migrating seems probable from their considerable content of fat. The Cape May Warbler is present in Florida only as a migrant. It seems logical to assume that, under ordinary circumstances, only during the seasons of migration would small birds such as warblers he available to nocturnal predators seeking flying prey. Here then, within the range of the Chuck-will’s-widow, is one more hazard which small night-migrants face. In this instance, however, circumstances allow a certain degree of speculation as to the time of capture of the warblers. Judging from the condition of the three birds, it seems unlikely that they were captured before dusk on 17 October or, for that matter, early that night. Considering the stage of digestion of the insects in the stomach of the Yellowthroat and of that of the diurnal locusts in the stomach of the Chuck-will’s-widow, it seems far more likely that these insects were taken in daylight on 18 October. Thayer (1899. Auk, 16:273-276) presented a fascinating account of Chuck-will’s-widows capturing migrating warblers over the open ocean during daylight. Similarly, this Chuck-will’s-widow at Miami .Shores may be suspected of gathering its warblers at dawn or during early morning hours, both prey and predator, possibly, being engaged in building up or replenishing fat reserves prior to migration beyond the shores of Florida. The fact that the Chuck-will’s-widow can capture small birds in daylight requires emphasis, for as Thayer’s (op. cit.) observations showed, this migrant stands in the unique position of being able to feed while enroute over the ocean, a potential which exclusively terrestrial birds quite generally lack. — Oscar T. Owhe, Department of Biology, University of Miami, Coral Gables, Florida 25 August 1966. Septemlier 1907 Vol. 79, No. 3 GENERAL NOTES 343 Josselyn Van Tyne’s Common Nighthawk nesting return. — Among the notes and files turned over to me for “Fundamentals of Ornithology,” I found three paragraphs of a first draft of a paper which Josselyn Van Tyne obviously intended to finish as a general note on the return of a Common Nighthawk (Chordeiles minor) to its breeding ground. Van Tyne had prepared some bibliography cards on the subject through 1952. The three paragraphs are hand-written on the hack of a page of Conservation News, dated 15 May 1955, so we can only assume that this is the approximate time that he jotted down his first ideas. It is almost certain that he did no further work on the project because, despite his remarkable command of current world literature on birds, he did not include a reference to Dexter’s second paper on Common Nighthawk returns ( 1956. Bird-Banding, 27 :9-16) . Why Van Tyne did not complete the short note is purely conjectural at this time. He spent the period of 10 to 26 June 1955, in field studies: 12-13 and 24-26 June in his Kirtland’s Warbler study area in Crawford County, and the intervening period in Michi- gan’s Upper Peninsula with Dr. L. H. Walkinshaw and Dr. and Mrs. W. Powell Cottrille. He was also devoting a considerable amount of time to the AOU Check-List during this general period. Van Tyne’s hand-written notes read as follows: “While studying Kirtland’s Warblers with us in June, 1942, ten miles southeast of Mio, Oscoda County, Michigan, Frances Hamerstrom found a Nighthawk nest with 2 eggs in a little open area on a hillside among the jack pines that sheltered the Kirtland’s Warblers. “On 20 June 1942, 1 set a carefully concealed bow-net at the nest and caught and banded the incubating female (No. 41-222357). “We studied the same area in 1943 but found no Nighthawk nest. However, on 24 June 1944, I found a nest in a similar habitat 450 feet south of the 1942 nest. Capturing the female with a bow-net, 1 found that 1 again had No. 41-222357.” The area “ten miles southeast of Mio, Oscoda County” was in Section 19, T25N, R4E. Parks (1946. Bird-Banding, 17:168) reported on a Common Nighthawk which returned to lay its eggs on the roof of the same high school in two successive years, in Hartford, Connecticut, and Dexter (1952. Bird-Banding, 23:109-114; 1956. Bird-Banding, 27:9-16) told of the return of a banded bird to the roofs of several buildings of Kent State University in Ohio. Van Tyne, however, appears to have been the first person to make observations on a banded Common Nighthawk returning to the same general nesting area on the ground, the original primitive nesting site for this species. It may he re- called that Van Tyne also was the first ornithologist to show by banding that passerine birds return to the same wintering ground in the tropics (1932. Bird-Banding, 3:110). — Andrew J. Berger, Department of Zoology, University of Hawaii, Honolulu, Hawaii, 14 July 1966. Retarded or arrested cranial development in Myiornis ecaudatus. — A pair of Short-tailed Pigmy-tyrants, i Myiornis ecaudatus) were obtained, 19 August 1966, from rain forest, near Los Guaraunos, Estado Sucre, Venezuela. They were feeding two nestlings that were nearly ready to leave the nest. While preparing the specimens, we observed that both had partially pneumatized or incompletely ossified skulls. The frontals and parietals were almost ('ompletely un- pneumatized (single-layered), thin, transparent and flexible structures. Only the anterior parts of the frontals and posterior parts of the parietals were pneumatized TIIK W1I.S()^ BULLETIN S(‘|ilcml)cr 1967 \ ol. 79, No. ;5 < (louhlf-laycred ) . In jiasscrincs, this condition is usually found only in tlie sexually immature birds wliereas, actually hrcedinjr adults have a comjiletely pneumatized skull. Ihis condition of un{)n('umatized skull has been report«“d in individuals of several jiasseriiK' species whicli were sexually mature or actually rejiroducing. Notewortliy are tlu‘ followiiifi;: Luxia curvirostra (McCabe and .McCabe, 1933, (Condor, 35:136 147); Qiielea quelea (Disney and Marshall, 1956. Proc. Zoo/. Soc. London, 127:379-387); Lepidoco/apfes /achrymi^er, Eu.scarthmorni.s f'ronadensi.s, Eloenia ol)Scura, Mionecles striaticoHis, Myadestes nd/oides, Mo/othrus Itonoriensis, Tanagra xanlhoga.ster (MilU'r, 1963. Univ. (ddifornia l*idd. Zoo/., 66:1-78), Syna//axi.s a//)e.scen.s ( Miller, 1955. Ada XI (,ongr. Intern. Ornith. Base/, p. 495-503). Crant (1966. Arner. Mid/and Nat., 75:142-149) also observed the same {ibenomenon in Myiopagis viridicata and gave a good review of tlie genera and families in which retarded or arrested skull ossification has been reported. According to Dwight (1900. Ann. Netv Yor/c Acad. Sc/., 13:73 360) and Nero (1951. W i/son Bu//., 63:84 88), the skulls of passerine species appear to pneumatize completely at about eight months of age. On the other hand. Miller (1963. op. cit.), indicated that in some of the tody-flycatchers there are single-layered regions in the skull that may prove to he permanent. Concerning the genus Mionectes, Miller (1963) said, “the skull either is slow in attaining adult double-layered condition throughout or never attains this state in some individuals." He also reported (Miller, 1946. Bird-Banding, 27:33-35) that complete pneumatization (doubling) may never he complete in some non- oscine families such as the Furnariidae. Since Ylyiornis ecaudatus is not biologically well known, we can not specify whether or not the incomplete pneumatization is the result of an arrested or a retarded process. Neither can we say that this phenomenon is of usual occurrence in this species. It also seems possible that individuals of this species are sexually mature or actually reproducing while still being very young as indicated by the presence of unpneumatized skulls. We thank Mr. .lames Dale Smith for helping in the preparation of the manuscript, and the Shell Foundation of Venezuela who provided a vehicle for field work. This study is a byproduct of ecological research while the senior author was a Ph.D. student of the Department of Zoology of the University of Montreal. Financial support was given by the University of Oriente in Venezuela anti the National Research Council of Canada. — Raymond McNeil and Aida Mahtinp:z, Departamento de Bio/ogia, Universidad de Oriente, Cumana, Sucre, V enezue/a, {Present Address iMcNeii), Department of Zoo/ogy, University of Montreal, Montrea/, Canada.) P2 Septenii)er 1966. The gaping response of nestling Bank Swallows. — Because of the hole-nesting habit of Bank Swallow^s i Riparia riparia) the liehavior of the young on the nest is difficult to observe. Beyer (1938. If i/son Bu//., 50:122-137) observed Bank Swallows on their nest by digging an observation hole behind their burrow. He reported that the parents gave a high pitched call when entering the nest. If this did not release gaping, the adults would nudge the young. In the summer of 1964 I undertook to study the gaping response of young Bank Swallows from an observation hole similar to that described by Beyer (op. cit.). On 7 .luly 1964 near the W. K. Kellogg Biological Station of Michigan State University, Barry County, Michigan, I found a large Bank Swallow colony and began construction of an observation hole. The nest contained three young estimated from Beyer's fledging dates to he eight days old. Before completion of the hole I observed that the young birds gaped vigorously and gave begging calls when I darkened the nest chamber by placing Soiiteniher l'K)7 Vol. 7'), Nu. 3 GENERAL NOTES 345 my hand over the burrow entrance, as they did when I Ijrightened the nest chamber with a flashlight. The young birds were 10 days old when I was first able to observe them inside the nest. The young gaped when the adults entered the burrow, even if the adults did not walk hack to the nest chamber. Although I could hear the begging calls of the young, in none of the observation periods did I hear the adults give any call upon entering the nest. The nestlings lifted up their heads when a shadow from another bird passed across the burrow entrance, but they did not gape. The next day I noted the same behavior. On the 12th day of the birds’ life it was cloudy and rainy all day. The young were fed at intervals of 15 to 30 minutes. Perhaps due to the infrequent feeding, the young gaped at shadows that passed over the burrow; and once when I shined a flashlight through the glass plate between my observation hole and the nest chamber, they all turned and gaped widely toward it. In all previous observations the nestlings did not move off the nest; on the 13th, 14th, and 15th days, however, two of the nestlings were continually off the nest and about one-third of the way down the burrow. A third nestling remained on the nest. On the 16th and 17th days all three young were fed at the entrance of the burrow. They gaped whenever another bird hovered about them. On the 18th day the nestlings had fledged, and for the next three days I found them on the nest only at night. Nestling Bank Swallows apparently do not gape in response to a call from the parents, hut rather either to a change in lighting or to the approach of another swallow. — George W. Fulk, Department of Zoology, Michigan State University, East Lansing, Michigan, {Present address: Department of Zoology, University of Rhode Island, Kingston, Rhode Island ) . Seasonal variation in bill length of House Sparrows. — In the course of an investi- gation of geographic variation of House Sparrows (Passer domesticus) , data were ob- tained which further demonstrate seasonal variation in bill length of this species. Speci- mens were collected at Kit Carson, Cheyenne Co., Colorado, in mid-October, 1964, and in late August, 1965. Measurements of the bill were taken from the anterior margin of the nostril to the tip of the mandible, and were recorded to the nearest 0.1 mm. Only adult birds (as determined by cranial ossification) were used in the present study so as to ensure that the samples are comparable. Statistical treatment was by analysis of variance (Steel & Torrie, 1960. “Principles and Procedures of Statistics.” McGraw-Hill, New York) . A statistically significant variation in hill length among groups was indicated ( see Table 1). However, no portion of this variation could be attributed either to differences between sexes (P>0.10) or to an interaction component (P>0.10). All of the variation in bill length could be assigned to effects of season of capture (0.025 >P> 0.010), birds obtained in August having longer hills than birds captured in October. The results are in essential agreement with reports by Clancey (1948. Brit. Birds, 41: 115-116) and Davis (1954. Condor, 56:142 149) which indicate that hills of House Sparrows are longer in summer than in autumn and winter. Presumably this variation has as its basis seasonal changes in food habits of sparrows (Davis, op. cit.; Sclander and .Johnston, 1967, Condor, 69:217-258) ; wear to the hill is thought to l)c greater during late autumn and winter when the primary foods are seeds than it is in summer when a substantial part of the diet is soft-hodied insects. MG TIIK WII.SON BULLETIN September 1967 Vol. 79, No. 3 J^AliLE 1 Bill Llngiii ok Hou.sk Sparrows (mkan plus standard krror) Sex Aufiust Octolter Female 9.42 ±0.122 9.27 ± 0.100 (6)* (12) Male 9.44 ± 0.053 9.04 ± 0.104 (7) (9) * Sample size. Furthermore, ul)sence of differences in l)ill length tliat are related to sex supports earlier contentions that North American House Sparrows have not undergone evolutionary change effecting a partitioning of the food niche (Packard, 1967. Syst. Zool., 16:73-89; Selander and Johnston, op. cit. ) . Presumahly, failure of House Sparrows to experience evolutionary change of this sort is related to their exploitation of an abundant and diverse food source, thereby obviating specialization of hill structure for restricted food sources (Selander, 1966, Condor, 68:113-151). — Gary C. Packard, Department of Zoology and Entomology, Clemson University, Clemson, S.C., 9 September 1966. lliiusiial activities of a House Sparrow and a Blue Jay at a Tufted Titmouse nest. — A Tufted Titmouse (Pams hicolor) pair nested in a Bluebird iSialia sialis) nest box in my yard at Pennington, N.J. On the morning of 4 July 1965 the titmouse young were fed by a female House Sparrow (Passer domesticus) on three occasions within a 40-minute period. She was also making frequent feeding flights to her nestlings in a bird house 17 ft. away. The titmouse pair protested noisily by scolding and diving and once successfully drove her away. The following morning (5 July) as I watched closely to see if the sparrow would return, a Blue Jay (Cyanocitta cristata) flew to the titmouse nest box just as an adult titmouse left, perched on the lower rim of the nest hole, pushed its head and neck well into the nest box and pecked eight times at the nest contents. Then it perched a few moments on an adjacent branch, 10 inches away, before returning to peer in the nest box and poke at the nestlings. Once again it perched on the branch, returned, and poked into the nest box. The jay did not taken anything from the nest. Although the titmouse pair protested noisily by scolding and diving at the jay as it perched on and near the nest box, they did not deter the jay. The entire incident took nine minutes. Twenty-nine minutes later a jay (same?) flew to the nest box, thrust its head and neck into the box as before, poking three times at the contents before leaving slowly up through the nest tree, branch by branch. The design of the box was such that it was 8V2 inches deep in front hut only 8 inches at the hack with the almost-square interior 5 inches wide. The nest rim was approxi- mately 3)4 inches below the box entrance hole and it seems possible that the jay could have reached the nestlings. There were ample auditory and visual cues to the nest’s location for a potential predator. The titmouse nestlings were very noisy when fed by the adults and at times the nestlings continued calling after the feedings. Moreover, the adults generally flew directly to the nest box hole with food. Sei)teml)cr 1967 Vol. 79, No. 3 GENERAL NOTES 347 The four titmouse nestlings fledged on 5 July. I was unable to determine if the nestlings were injured by the jay’s thrusts. Inspeetion of the nest and box disclosed no signs of blood. — Kenneth W. Pkescott, New Jersey State Museum, Trenton, New Jersey, 24 May 1966. Exltralimital breeding of Painted Buntings in Florida. — On 8 July, 1966, two singing male Painted Buntings ( Passerina ciris) were found on the northeastern out- skirts of Apalachicola, Franklin County, Florida. The buntings were adjacent to the Apalachicola River, about one-half mile from the Gulf coast, in an open growth of willow {Salix sp.), chinaberry {Melia azedarach) , and wax-myrtle iMyrica cerijera), with a thick understory, predominately of blackberry (Rubus sp.) and sesbania [Sesbania sp.). On a second trip to the area on 29 July, 1966, two males were again singing, and a third male, also in song, was located nearby in similar habitat. Breeding was suspected when two juveniles were located near the third male. They were actively fed by a dull, female-like hunting, showing faint reddish on its underparts. This small colony at Apalachicola is located near the center of a hiatus in the Painted Bunting’s breeding range; a 400 mile break between southern Alabama (Mobile County: Imhof, 1962. “Alabama Birds”) and coastal portions of eastern Georgia and northeastern Florida (Burleigh, 1958. “Georgia Birds”; Sprunt, 1954. “Florida Bird Life”). The absence of breeding buntings in Florida portions of this hiatus has been corroborated at Pensacola by Weston (1965. A Survey of the Birdlife of Northwestern Florida, Bull. Tall Timbers Research Station, No. 5. Tallahassee.), and throughout the interior and Gulf coastal regions of North Florida by H. AI. Stevenson and his workers during recent state-wide field investigations of breeding birds. No Painted Buntings were found at Apalachicola during previous summers (Stevenson, personal communication), however, two summer records near Tallahassee, in 1962 and 1966 (Robertson, 1962. Audubon Field Notes, 16:47; Stevenson, 1966. Audubon Field Notes, 20:564), of single, singing males, are the first known summer occurrences for that area, and suggest that the appearance of the Painted Buntings at Apalachicola may he part of a trend towards occupation of the hiatus. The factors which brought about this wide gap in breeding range are not understood. Suitable breeding habitat appears to exist throughout the range-gap, and migrant Painted Buntings are regularly found in small numbers along the northeast Gulf coast in spring, adjacent to the unoccupied area. The presence of these migrant huntings along the coast may he due to displacement of trans-gulf migrants by weather associated with northwesterly cold fronts crossing the Gulf of Mexico. The possibility that such displacement resulted in the establishment of the colony in Franklin County, Florida, seems good. Several cold fronts did cross the Gulf during April and May, 1966, resulting in eastward displacement of trans-gulf and western migrants ( Cunningham, 1966. Audubon Field Notes, 20:497). An area-wide field count on 22 April, 1966, in Phanklin and adjacent Wakulla Counties, produced 13 Painted Buntings, second highest numl)er in the history of spring counts in these counties, and huntings at Alligator Point, Franklin County, on 7 May, and at Pensacola on 11 May, were the latest or e(jualed previous late spring records for those two areas respectively ( Cunningham, ( loc. cit.); Imhof, 1966. Audubon Field Notes, 20:518). — John C. Ogden and Frank L. (hi \pman. Depart- ment of Biological Science, Florida State University, Tallahassee, Florida, I September 1966. MH TiiK WILSON hulu:tin Sf'|)tpml)pr 1967 \ <.l. 79, No. :i (rolcifilich accept young after long and short incubation. — In the summer of 1%5, in Toledo, Oliio an experiment was carried out in which ejigs of the American Gold- fineh iSpinus Iri.sti.s) from clutelies just laid were exchanged for eggs that were in advane(‘d incubation. On 31 .July I exelianged eggs between nests of 11 day incubation and those where the fifth egg had just been laid. The eggs that had been laid for only the short time were taken by a predator on the following day. The other female Goldfinch continued to ineuhat(; for an additional 12 days until tlu; entire clutch had hatched. .She had been incubating for a total of 23 days. 1 was not able to examine this nest until 10 days later. At that time the nest looked “used” hut since there was no defecated material on the nest it would ap{>ear that the young had not been in the nest for long. On 5 August, I exchanged eggs that were in day four of incubation with a clutch that had two eggs pi{)ed. The eggs hatched in both nests and the young were all fledged. The one female had incubated for about five days and the other had incubated for 19 days. The mean incubation period for this species has been reported as about 11-12 days, (Walkinshaw, 1938. Jack-Pine Warbler, 16:3-11 and 14-15). ITom the preceding experiments it is obvious that at least in some instances, the female will accept young after one-half the length of or twice the length of the mean incubation time. — L.AHtn' C. Holcomb, Department of Biology, (Creighton University, Omaha, Nebraska, 11 July 1966. New status for the Rufous-crowned Sparrow in Utah. — The first record of the Rufous-crowned Sparrow ( Aimophila ruficeps) for Utah (Wauer, 1965. Condor, 67:447) was based on a specimen taken at Oak Greek Canyon, Zion National Park, Washington County, Utah, 5 November 1963. The writer reported the species as wintering in Zion I’ark. He concluded that, “early fall records, in August, in Zion Park indicate a fall wandering tendency for the species, hut the presence of Rufous-crowned .Sparrows throughout the winter months appears to suggest a northerly movement in fall and, per- haps, a return to southerly breeding grounds in spring.” However, an immature Rufous-crowned .Sparrow (deposited at Museum of Vertebrate Zoology, University of Utah), taken by the author at Oak Creek Canyon, Zion National I’ark on 10 August 1965, suggested that the species may he more than a wintering resident there. It, like a specimen collected on 5 November 1963, was of the race scottii, according to Lester L. .Short. The possibility was suggested that the species resides permanently in the vicinity, nesting on the upper slopes of the canyons and moving into the lower canyons after nesting and to winter. In Arizona, the species is a spring to late summer nester; its period of breeding closely tied with summer rainy season. Brandt (1951. “Arizona and Its Bird Life” p. 702) reports a completed nest as early as 24 May, nests as late as 15 August, and that the height of the season for fresh eggs is during the latter half of June. Assuming that the species did reside within the Zion Canyon area, the author searched appropriate habits during May and June, 1966; on 29 June on the west slope of .Steven’s Wash, Parunuweap Canyon of Zion National Park, a lone singing adult was found. 1 watched it for several minutes through 9X binoculars. It moved to several perches within an approximate 100 foot circle singing all the while. Suddenly a second Rufous-crowned .Sparrow, its hill full of grass, flew^ to a perch about two feet from the singing bird. Both remained there for five to ten seconds before they departed, flying up the slope and around a number of large rocks out of sight. I was unable to locate them again. Septt>inl)er 1067 Vol. 70, No. 3 GENERAL NOTES 349 Although I was not able to return to the scene before being transferred from Zion Park, this observation of one singing adult and another carrying nesting material offer good evidence of nesting. The habitat, too, is typical of Rufous-crowned Sparrow nesting grounds. The elevation is about 4,200 feet. Huge sandstone boulders dominate the seven degree slope where Pinus monophyl/a, Jiiniperus osteosperma, and Qiiercus garnbellii are common. The heavy patches of grasses that occurred there were under study as a choice “relict grassland” by LaMar Mason and James Carley of the Soil Conservation Service. Mason’s identifications of the major grasses on the site include needle-and- thread (Stipa comata) as the dominant grass, while Indian rice grass (Oryzopsis hymenoides) , black grama iBouteloua eriopeda), and mutton grass i Poa fendleri) were abundant. A portion of the above data was obtained during field research supported by National Science Foundation Grant No. GB-4035. — Roland H. Wauer, Big Bend National Park, Texas, 12 September 1966. ANNOUNCEMENT The XV International Ornithological Congress The International Ornithological Committee decided, at the close of the XIV Interna- tional Congress, that the next Congress would he held in the Netherlands in 1970 and appointed Professor N. Tinbergen as President. The Netherlands members of the International Ornithological Committee elected Professor K. H. Voous as Secretary- General and formed a Netherlands Executive Congress Committee. The International Committee accepted the Dutch proposal that the date of the Congress would fall within the first week of September, as it was feared that appropri- ate accommodation would not be obtainable earlier in the summer months. No major ornithological excursions will he organized, but in the middle of the congress week a variety of one-day excursions will he held. After full consideration the Netherlands Executive Congress Committee decided that the XV International Congress would he held at ’s-Gravenhage (The Hague), with the provisional date: 30 August-5 Septem- ber 1970. Applications for membership in the Congress will be accepted until 4 months before the opening date of the Congress, viz. till 1 May 1970. Applications for presenting papers and for arranging “Specialists Meetings” should reach the Secretary-General not late than 1 April 1969. Further information regarding the Congress can be obtained from The Secretary- General, XV International Congress, c/o Burgemeester de Monchyplein 14, The Hague, Netherlands. THE PKESJDENT’S PAGE The I’roceedinjis of our excellent 1%7 meeting, lield during 15-18 June at the (irawford House, New Hampshire, app(“ar elsewhere in this issue, as recorded hy Pershing H. Hofslund, who has completed his fifth and final year as the dedicated Secretary of this Society, As I exj)ress to him the grateful appreciation of all of us for the fine work which he has done, I would welcome, with similar gratitude, his successor, Jeff Swinehroad, who was elected Secretary at the June meeting. This specific example of one good man taking over from another illustrates a general point which one of our esteemed l^ast Presidents, Maurice Brooks, has made. Writing to me, shortly after the meeting. Dr. Brooks commented: “The setting was great, the crowd excellent, and the spirit encouraging as always.” He then said: “I never cease to marvel at the viability of this organization; year after year it comes up with devoted people who get the jobs done.” The continuing devotion of Past Presidents, as exemplified hy Maurice Brooks, is a large part of the viability of the Wilson Society. This continuity of devotion also can he seen in the fact that the symposium on nocturnal migration and orientation, which was an outstanding feature of the papers sessions at the meeting, was proposed hy a Past President, Sewall Pettingill, and was organized and chaired hy one of our Vice Presidents, William Gunn. Two Past Presidents, moreover, participated in the Saturday evening program, after the Annual Dinner: Dr. Pettingill as Toastmaster, and Dr. George Sutton as the speaker of the evening. Next year’s meeting, to he held at Southern Illinois University, Carhondale, Illinois, 2-5 May, 1968, will provide still another example of a Past President’s contribution to the viability of the Wilson Society. Roger Peterson will he the Chairman of a sym- {)osium on the preparation of state and regional bird hooks. In writing to say how pleasant the 1967 meeting was. Dr. Peterson said that he will enjoy planning and chairing the 1968 Symposium. The latter will he concerned with a subject of timely relevance. No one who is interested in North American birds can afford to miss it. But the point is that, busy man though he is. Past President Peterson is sufficiently devoted to the Wilson Society to take the time to organize this important symposium for next May’s meeting. Aaron M. Bagg ( As we go to i)iess, we learn that an unexpected commitment will make it impossible for Dr. Peterson to attend the Carhondale meeting, hut we expect to continue with the symposium which he had planned. — Ed.) CORRECTION The following correction should he made in the article, “A new subspecies of the Boat-tailed Crackle from Mexico,” Wilson Bull., 78:129 131 (1966). In Table 1 the weight data for females of the subspecies prosopidicola should read: (6) 117-137.6 (125.2) 350 ORNITHOLOGICAL NEWS FROM THE AOU At its annual meeting in Toronto, Ontario on 21 August 1966 the AOU elected the following officers: Harold F. Mayfield, President L. Richard Mewaldt, Secretary John W. Aldrich, First Vice-President Burt L. Monroe, Sr., Treasurer Eugene Eisenmann, Second Vice-President Oliver L. Austin, Jr., Editor The Brewster Medal was awarded to W. E. Clyde Todd for his hook, “Birds of the Labrador Peninsula.” Mr. Todd, the senior member of the AOU, is the first person to win the Brewster Medal for the second time. The Smithsonian Institution and the United States Department of the Interior have designated part of their page allotment under the National Science Eoundation transla- tion program for the six volumes of Dement’ev and Gladkov: “The Birds of the Soviet Union.” The series is being translated in Jerusalem by the Israel Program for Scientific Translations which holds the copyright. Drs. A. Birron and Z. S. Cole are the translators and Dr. Cole is editor. Volume 1 has already appeared and is available for $3.00, paper- bound, from the U.S. Department of Commerce, Clearing House for Federal Scientific and Technical Information, Springfield, Virginia 22151. The translation for Volume 4 has been completed and page proof has been read. It should appear in late 1967, barring unforeseen problems in the Middle East. Unfortunately, Dr. Cole died this year and translation has been interrupted. Before he died, however. Volume 6 was almost completed, volumes 2 and 3 were each about one third translated l)ut Volume 5 was not yet started. The schedule for issuing the remaining four volumes will Ije announced after a new translator and editor have been found. Royal Terns from coastal Virginia have recently been color banded as part of a study by P. A. and F. G. Buckley on variation in chick color. A total of ten different colors have been used (including light blue, purple and dark blue); three at a time plus one Fish and Wildlife band, have been placed on each bird, in unique combina- tions. Anyone observing such a banded bird is asked to send a postcard to Dr. Buckley, Department of Biology, Old Dominion College, Norfolk, Virginia 23508, with the following information on it: date, location, and observer’s name, plus the hand colors and their positions (upper/lower, right or left leg). Assistance in this project will be greatly appreciated. Joanna Burger and Richard Brownstein of Buffalo, New York, are working on the distril)ution and migratory behavior of the Bonaparte’s Gull. The gulls are dyed a bright color and banded. The color used denotes the date of the marking session. All birds are color marked in Buffalo. If you see any unusually colored Bonaparte’s Gull, please send the following information to Joanna Burger, Department of Biology, State University College, 1300 Elmwood Avenue, Buffalo, New York 14222: Date, Location, Color, Number of marked individuals, and the Number of unmarked Bonaparte’s Gulls with the color marked gulls. Any other data from personal records on the distribution and movement of these gulls would also he appreciated. 351 ORNITHOLOGICAL LITERATURE 'I'liK Him)S OK ( j>i,oK‘\i)o. 'I'wo volunu's. By Alfred \I. Bailey and Rol)ert J. Niedrach. Denver Museum of Natural History, 1965: 9 x 12% in., vol. 1, xxii + 454 pp., vol. 2, X -|- 455 pp., 124 col. pis., over 400 hi. and wli. photos, hack endpaper map in each volume. .Set of two volumes, .$85.00. News that another “state list'’ is about to appear always i)rovokes certain expectations. It will he a monumental piece of hook-makinji, sumi)tuous, an armload, and too his) 25.00 Transfer to Research Fund .. . .58.00 Total Disbursements $12,255.85 360 THE WILSON BULLETIN September 1967 Vol. 79, No. 3 Excess of Receipts over Disliursements for ^ ear 1966 $1,942.69 GENKHAL FI NU CASH ACCOUNTS Checking Account $3,115.95 Savings Account 6,705.00 Balance in Girard Trust Bank, Philadelphia, Pennsylvania, 31 December 1966 $9,820.95 JossELYN Van Tyne .Memorial Library Book Fund Balance as sIiomti hy last report dated 31 Decemher 1965 S 323.95 RECEIPTS .*^ale of duplicates and gifts 89.80 Total Balance and Receipts $ 413.75 DISBURSEMENTS Purchase of hooks and postage 198.40 Balance in Girard Trust Bank, Philadelphia, Pennsylvania, 31 Decemher 1966 S 215.35 Louis .\gassiz Fuertes Research Fund Balance as shown hy last report dated 31 December 1%5 S 132.00 receipts Contributions 31.00 Transfer from General Fund 58.00 Total S 221.00 disbursements .\ward to Douglas D. Dow $ 100.00 .\ward to Ralph W. Schreiber 100.00 Total Disbursements 200.00 Balance in Girard Trust Bank, Philadelphia, Pennsylvania, 31 Decemher 1966 S 21.00 Endowment Fund Balance in Endowment Fund Savings .\ccount as shown hy last report 31 December 1965 $ 225.51 receipts Life Membership payments Cash $1,325.00 Patronship payments Cash 1,100.00 Stock Dividends received (included below) 14 shares Massachusetts Investor's Trust Sale of 3 shares Standard Oil of California 248.12 Legacy from Estate of Frances A. Cook 100.00 Total Receipts 2,773.12 $ 2,998.63 expenditures — none S('pteiiil>er 1907 Vol. 79, No. 3 FORTY-EIGHTH ANNUAL MEETING 361 Balance in Endowment Fund Savings Account, Girard Trust Bank, Philadelphia, Pennsylvania, 31 December 1966 Securities Owned (listed at closing prices 31 Decemher 1966) Bonds 117,133.44 Preferred Stocks 3,427.50 Common Stocks 24,880.57 Total Securities Owned Total Endowment Fund 31 Decemher 1966 $ 2,998.63 $45,441.51 $48,440.14 Respectfully submitted, C. Chandler Ross Treasurer Research Grant Committee Report Secretary Hofslund summarized Chairman Tordoff’s report as follows: “We advertised the Louis Agassiz Fuertes Research Grant for 1967 through notices in the major American ornithlogical journals. Sixteen inquiries resulted in a total of ten completed applications. Once more we are impressed with the quality of the majority of the applications, and dismayed that we have only a single grant to award. “If funds are available for two awards, we recommend that the 1967 award he given to Dennis L. Kalma, Osborn Memorial Laboratory, Room 401, Yale University, New Haven, Conn. 00520, for his study entitled: ‘A Comparison of the Reproductive Ecolo- gies of a Temperate and an Equatorial Sparrow,’ and to Spencer G. Sealy, Department of Zoology, University of British Columbia, Vancouver, B.C., for his study: ‘Timing of Breeding Cycle in North Pacific Auklets.’ “The ten applications are being sent to the Secretary, who can then make them available for inspection by the Council. We suggest that all applicants he sent a letter announcing the results of the competition.” Conservation Committee Report Roland Clement, Chairman of the Conservation Committee, summarized the report for the attending audience. A complete report will appear in the next issue of The Bulletin. Membership Committee Report Chairwoman Hazel Bradley Lory reported that, “because of the chairman’s many other jobs and responsibilities, her membership work for the Wilson Ornithological Society is always done by ‘fits and starts.’ Starting in September, the committee was weeded out by dropping those members who had not secured any new members or who felt they could not continue to do membership work. “Nine of the old members were retained and two new ones were added in the fall. These people were each supplied with names of ten prospective members to whom they were asked to write an invitation to join this society. “Two later ‘fits’ of activity in January and February resulted in the addition of five more members to the committee, bringing the total to 16 plus the chairman. The five, too, were supplied with ten or more names of prospects whom they were to ask to join. “The Treasurer, Chandler Ross, reported as of 15 May, we had 71 dropouts, 28 resigna- tions, 11 deaths — 110 on the debit side as compared with 127 reported last year. We have about 47 new subscriptions and 131 new members on the list to he posted. Thirty 362 TIIK WILSON BULI.ETIN September 1967 \ ol. 79, No. 3 of the new inenihers were enlisted directly by tlie efforts of the membership committee, s(!ven by Secretary Hofslund, five by Georjie Hall, and two by the President. “Again this year, as in previous years, a goodly number of our new members are students (36.7%) or teachers (19%).” Library Committee Report Secretary Hofslund read the following report as submitted by Chairman William Lunk: “The year was marked by no notable events in connection with the Josselyn Van Tyne Memorial Library, and its affairs ran smoothly. Norman Ford, of the Museum of Zoology Bird Division, continued in direct charge of all details; and we learn with regret that by the time another few months have passed be will no longer be here. The value of bis services has been tremendous, during some critical times in the library’s development. “Gifts received during the year total 60, from 43 donors. In all, 34 books, 147 journals, 3,563 reprints, 24 translations, and 7 pamphlets were accepted. “Of the reprints, 3,300 made up the current increment of Mrs. Josselyn Van Tyne’s generous gift of her late husband’s personal library. “Seventy-five out-of-town loans, of 187 items, were made to 57 individuals. This showed an encouraging increase over last year’s total. And, of course, constant use of the collection is made in the building by local and visiting members. “As reported last year, 117 journals are regularly received, 91 of them by exchange for The Wilson Bulletin. “Use of the library by all research-minded members is continually urged, as are the donation of books and other items, and contribution to our New Book Fund.” Endowment Committee Report Endowment Committee did not function as such in 1966. Temporary Committees The following committees were appointed by President Bagg: Auditing Committee Nominating Committee Resolution Committee Edward L. Altemus Maurice Brooks Andrew J. Berger Alan Crawford, Jr., Chairman Roger Tory Peterson Roland Clement, Chairman John H. Foster Phillips B. Street, Chairman Ralph Dexter Second Business Session The Secretary read the report of the Auditing Committee: “On June 2 we conducted our annual audit of the Treasurer’s books and records, including an examination of receipts and expenditures in detail. The exemplary devo- tion to the task of Chandler Ross continues to he evident. All records are in order and the Society remains in excellent financial condition.” Report of the Resolutions Committee Chairman Roland Clement gave the following resolutions whieh were passed without a dissenting vote by members in attendance at the meeting: WHEREAS the officers and members of the Audubon Society of New Hampshire, as hosts to this 48th annual meeting of the Wilson Ornithological Society, have contributed immeasurably to the success and pleasure of all of us in attendance through their advice September 1967 Vol. 79, No. 3 FORTY-EIGHTH ANNUAL MEETING 363 and assistance in attending to the thousand and one details that were quietly taken care of in order to provide the smoothly functioning organization of this meeting, both indoors and afield, THEREFORE BE IT RESOLVED that the Wilson Ornithological Society — its council, officers, and members — do extend a formal and warm-hearted expression of apprecia- tion to President Tudor Richards and all his colleagues in the Audubon Society of New Hampshire for untiring efforts on our behalf. WHEREAS the selection of so happy a meeting place in a lovely natural environment; and the selection of such a stimulating program of papers and films as we have enjoyed at this meeting bespeaks creative leadership and hard work over many months by the Officers of the Society THEREFORE BE IT RESOLVED that The Wilson Ornithological Society and more particularly we members and guests who have been the beneficiaries of these services — do, at this 48th Annual Meeting of the Society held at Crawford Notch, N.H., this 17th day of June, 1967, express our warm appreciation to all the Officers of the Society, and more particularly to its President and committee members, to Dr. W. W. H. Gunn for arranging the productive symposium on bird orientation, and to Dr. George Miksch Sutton and Mr. Stuart Keith for so graciously contributing their fine film programs. WHEREAS the success and rewards of this 48th Annual meeting of The Wilson Ornithological Society owe an obvious debt to the forethought, hard work, and devotion and patience of the Local Committee on Arrangements; and WHEREAS our comfort and physical well-being while in attendance at this 48th Annual meeting on the edge of the northern spruce wilderness is almost equally obviously dependent on the physical and administrative facilities so ably provided us by Craw- ford House and its management and staff, THEREFORE BE IT RESOLVED that The Wilson Ornithological Society assembled in annual meeting at Crawford Notch, N.H., this 17th day of June, 1967, does extend its warm appreciation to Chairman Robert W. Smart and all the members of his Local Committee on Arrangements; and to the Management and Staff of Crawford House, for the exceptional attention they have given to our every need. WHEREAS it is well-known to many of us that Norman I. Ford of the University of Michigan’s Museum of Zoology has contributed many years of dedicated service to the maintenance of this Society’s Josselyn Van Tyne Memorial Library, and WHEREAS Mr. Ford will soon leave the University of Michigan to assume new duties elsewhere, THEREFORE BE IT RESOLVED that The Wilson Ornithological Society, assembled in 48th Annual Meeting at Crawford Notch, N.H., on this 17th day of June, 1967, does express its deep appreciation to Norman I. Ford for his years of devoted service to the Society and does extend its heartiest good wishes in his new undertakings. WHEREAS the Quetzal has for centuries been one of the New World’s most celebrated birds, both because of its striking beauty and its symbolic significance as the national bird of Guatemala, and WHEREAS the habitat of this exciting species is being destroyed rapidly and irrevocably for lack of adequate ecosystem conservation programs within its range, and WHEREAS the very rarity of this bird has augmented demands for its capture as zoo, pet, or other uses, thus further threatening it with extinction. THEREFORE BE IT RESOLVED that the Wilson Ornithological Society, assembled in its 48th annual meeting at Grawford Notch, N.H., on this 17th day of June, 1967, offer its aid and encouragement to the Pan-American section of the ICBP and the Latin 364 THK WILSON HULLETIN Scpteml)pr 1967 Vol. 79, No. 3 American desk of the Nature Conservancy in working for any and all habitat preserva- tion and protec^tive measures that may contribute to the perpetuation of this valuable and beautiful species. WHEREAS it is known, through the field research of the large cooperating group of federal, state, university, and private investigators who have contributed to the National Audubon Society’s cooperative Bald Eagle Research and Conservation Program that our national bird’s decline is due in part to disturbance during the nesting cycle and to loss of habitat — particularly nesting trees — during necessary land uses such as forestry — to wanton shooting, and very probably to food-chain poisoning due to a variety of environmental pollution problems, THEREEORE BE IT RESOLVED that the Wilson Ornithological Society assembled in annual meeting at Crawford Notch, N.H., on 17 .June 1967, does extend a formal expression of appreciation and congratulations to the Northern States Power Company, with headquarters in Minneapolis, Minn., for its leadership in recognizing the conserva- tion needs of our national bird, the Bald Eagle, and having implemented a series of special conservation measures to favor the reproductive success of this great bird along some seventy miles of the St. Croix River, north of Taylors Falls, Minn., and helped publicize the importance of such corporate participation in the conservation program on behalf of the Bald Eagle by the placing of conspicuous advertisements in the W all Street Journal and elsewhere; and BE IT FURTHER RESOLVED that copies of this resolution he communicated to the President of Northern States Power Company and included in the report of this meeting to appear in the Society’s Wilson Bulletin in due time. WHEREAS it is known, through the field research of the large cooperating group of federal, state, university, and private investigators who have contributed to the National Audubon Society’s cooperative Bald Eagle Research and Conservation Program that our national bird’s decline is due in part to disturbance during the nesting cycle and to loss of habitat — particularly nesting trees — during otherwise necessary land uses such as forestry — to wanton shooting, and very probably to food-chain poisoning due to a variety of environmental pollution problems, THEREFORE BE IT RESOLVED that the Wilson Ornithological Society assembled in annual meeting at Crawford Notch, N.H., on 17 June 1967, does extend a formal expression of appreciation and congratulations to the Red Lake Band of Chippewa Indians, who, on 5 April 1967, under the leadership of their Tribal Council, did declare their 564,000 acre reservation in northwestern Minnesota an eagle sanctuary and adopt a nest-protection program as part of the forest management program of this large reservation in cooperation with the Bureau of Indian Affairs and the U.S. Fish and Wildlife Service, and, BE IT FURTHER RESOLVED that a copy of this resolution he sent to the Chief of the Red Lake Band of Chippewa Indians. WHEREAS it is known, through the field research of the large cooperating group of federal, state, university, and private investigators who have contributed to the National Audubon Society’s cooperative Bald Eagle Research and Conservation Program that our national bird’s decline is due in part to disturbance during the nesting cycle and to loss of habitat — particularly nesting trees — during otherwise necessary land uses such as forestry — to wanton shooting, and very probably to food-chain poisoning due to a variety of environmental pollution problems, THEREFORE BE IT RESOLVED, that the Wilson Ornithological Society, assembled in annual meeting at Crawford Notch, N.H., on 17 June 1967, does extend a formal Sfi)tcnil)er 1967 Vol. 79, No. 3 FORTY-EIGHTH ANNUAL MEETING 365 expression of appreciation and congratulations to the Boise-Cascade Corporation, a large timber-holding corporation with headquarters in Idaho, for its leadership in recognizing the conservation needs of our national bird, the Bald Eagle, and having implemented a series of special conservation measures to favor the reproductive success of this great bird on some 325,000 acres under its control and management in Min- nesota, and BE IT FURTHER RESOLVED that a copy of this resolution he sent to the presi- dent of the Boise-Cascade Corporation. WHEREAS it is known, through the field research of the large cooperating group of federal, state, university, and private investigators who have contributed to the National Audubon Society’s cooperative Bald Eagle Research and Conservation Program that our national bird’s decline is due in part to disturbance during the nesting cycle and to loss of habitat — particularly nesting trees — during otherwise necessary land uses such as forestry — to wanton shooting, and very probably to food-chain poisoning due to a variety of environmental pollution problems, THEREFORE BE IT RESOLVED, that the Wilson Ornithological Society, assembled in annual meeting at Crawford Notch, N.H., on 17 .lune 1967, does extend a formal expression of appreciation and congratulations to the National Audubon Society, the U.S. Forest Service, and the U.S. Fish and Wildlife Service for their successful col- laboration in working out cooperative land-use management programs which will mini- mize disturbance of Bald Eagles during their nesting cycle, and otherwise protecting nesting sites in the forested areas of the Great Lakes region, involving not only federal and state lands but corporate and private land holdings as well, and BE IT FURTHER RESOLVED that copies of this resolution he communicated to the President of the National Audubon Society, the Director of the U.S. Forest Service, and the Director of the U.S. Fish and Wildlife Service. Election of Members and Officers The proposed new members as posted by the Chairwoman of the Membership Com- mittee were elected without dissenting vote. The Nominating Committee presented the following slate for the 1968 offices: Presi- dent, Aaron M. Bagg; First Vice-President, H. Lewis Batts, Jr.; Second Vice-President, William W. H. Gunn; Secretary, Jeff Swinehroad; Treasurer, C. Chandler Ross; Elective member of the Council to fill the unexpired term of Jeff Swinehroad, Pershing B. Hofslund (term expires 1968); Elective Member of the Council, Andrew J. Berger (term expires 1970). The report of the Nominating Committee was accepted and the slate was elected without dissenting vote. Papers Sessions 1. Tudor Richards, Hollis, New Hampshire. The Bird Life of the White Mountain Region of New Hampshire, Past and Present. 2. Richard C. Banks, U.S. National Museum. Comments on Variation in the Red- breasted Nuthatch. 3. Elden W. Martin, Bowling Green State University. A Comparison of Bird Pre- serves and Prevailing Attitudes toward Naturalists in Great Britain and the United States. 4. Ralph W. Dexter, Kent State University. Banding and Nesting Studies of Marine Birds at Cape Ann, Massachusetts. 366 THE WILSON BULLETIN Seiitcinher 1967 Vol. 79, No. 3 5. William (i. (ieorge, Southern Illinois University. Feeding' Behavior of Wintering White-winged Crossbills in Southern Illinois. 6, Chandler S. Rohhins and Willet T. Van Vel/.en, Migratory Bird Populations Station, Laurel, Maryland. The Breeding Bird Survey, a Cooperative Program for Measuring Population Changes. 1. Salvatore F. Ihingiorno, Rutgers University. The Use of Marginal Breeding Areas by Laughing Gulls f Larus atricillaj. 8. Ian A. McLaren, Dalhousie University. The Current Status of the Ipswich Sparrow on Sable Island. 9. Kenneth C. Parkes, (iarnegie Museum. Migration, Banding, and Taxonomy. 10. Flight Lieutenant A. U. Herbert, Canadian Forces Base Rivers, Ohodo, Manitoba. Vertigo in Pilots as It Might Be Experienced in Birds. 1 1. Raymond P. Coppinger, Amherst College. Reactions to Novel Stimuli by Hand- reared and Wild Caught Birds. 12. David Krieg, St. Bonaventure University. Courtship Feeding in the Eastern Bluebird. 13. Frank Bellrose, Illinois Natural History Survey. The Physical Nature of Bird Migration. 14. Jeff Swinehroad, Rutgers University. Orientation of Nocturnal Migration over New Jersey. 15. W. John Richardson, McMaster University. Radar Studies of Bird Movements in Canada: an Interim Report. 16. William H. Drury, Jr., Massachusetts Audubon Society. Radar Studies of Song Bird Migration in Massachusetts. 17. Sidney A. Gauthreaux, Louisiana State University. Bird Migration as Simultane- ously Viewed by Telescope and Radar. 18. William W. Cochran, Illinois Natural History Survey. Aerial Telemetric Studies of Nocturnal Migration of Passerines. 19. Charles Walcott, Tufts University. Airplane Tracking of Single Pigeon Homing. 20. Lester Talkington, University of Wisconsin. Helicopter Studies of Pigeon Homing. 21. Richard L. Penney, Institute for Research in Animal Behavior, New York Zoolog- ical Park. Tactics in the Study of Bird Orientation. 22. Douglas James, University of Arkansas. Passerine Orientation in a Planetarium. 23. Stephen T. Emlen, Cornell University. The Ontogeny of Migration Orientation. 24. R. W. Dickerman and G. Gaviho T., Cornell University Medical College. Nesting Studies of the Green Heron in Mexico. 25. Allen Keast, Queen’s University. Bird Adaptations to Desert, with Reference to Australia. 26. William A. Klamm, Lakewood, Ohio. Some Observations on Competition between Lewis’ Woodpeckers and Red-shafted Flickers. 27. Devin A. Garrity, Rye, New York. Antarctic W ildlife. Attendance Members and guests who registered totaled 279 persons. Twenty-eight states, the District of Columbia, four Canadian provinces, and Bermuda were represented. From Arkansas: 1 — Fayetteville, Douglas James. From Connecticut: 13 — Ansonia, Noble Proctor; Bristol, J. Stanley Quickmire; Mid- dlebury, Mr. and Mrs. Newell W. Mitchell; Norwalk, Roland C. Clement; Old Lyme, Dr. and Mrs. Roger T. Peterson; Orange, Phillip R. Sharp; Riverside, Bruce Adams; Simsbury, Mr. and Mrs. Harold S. Peters; Storrs, Mr. and Mrs. David N. Doubleday. Sc[)teinhpr 1967 Vol. 79, No. 3 FORTY-EIGHTH ANNUAL AIEETING 367 From Delaware: 2 — Middletown, Mrs. Richard Herliert; Newark, Warren R. Faust. From Florida: 1 — Winter Park, Mrs. Marjory B. Sanger. From Hawaii: 1 — Honolulu, Andrew J. Berger. From Illinois: 7 — Carbondale, William G. George; Monience, Hazel Bradley Lory; Urbana, Mr. and Mrs. Frank Bellrose, Mr. and Mrs. William Cochran, William J. Francis. From Indiana: 3 — Richmond, Mr. and Mrs. M. S. Markel, J. Schnell. From Iowa: 2 — Grinnell, Helen Treat Stewart, Mildred Stewart. From Kansas: 1 — Emporia, David F. Parmelee. From Louisiana: 4 — Baton Rouge, Mr. and Mrs. William Buskirk, Sidney Gauthreaux, Jr., Robert J. Newman. From Maine: 10 — Brunswick, Dr. and Mrs. Alfred 0. Gross, Mr. and Mrs. Charles E. Huntington, Mr. and Mrs. F. Burton Whitman, Jr.; Orono, Mr. and Mrs. Edward J. Danforth; Portland, Mr. and Mrs. Edward F. Dana. From Maryland: 8 — Baltimore, William Sladen; Beltsville, Orrey P. Young; Chester- town, Mr. and Mrs. Edward Mendinhall; Chevy Chase, Mr. and Mrs. Elting Arnold; Laurel, Chandler S. Robbins; Towson, Gladys Hix Cole. From Massachusetts: 35 — Amherst, Mr. and Mrs. Lawrence Bartlett, Mr. and Mrs. Raymond Coppinger; Andover, Juliet Kellogg; Arlington, Doris Atwater; Athol, Steven Piragis; Boston, Haven H. Speneer; Cambridge, Kimball Elkins, John Minot; Dover, Mr. and Mrs. Aaron M. Bagg; Gardner, Henry F. Howe; Lawrence, Dennis Coskren, Michael Coskren; Lincoln, James Baird, Charles Walcott; Lyn field, Mr. and Mrs. Robert Rathbone; Middleboro, Kathleen S. Anderson; Nahant, Donald C. Alexander; Newtonville, Katherine Curtis, Eleanor B. Riehmond; North Andover, Oscar M. Root; Petersham, Robert A. Clark, Mr. and Mrs. John Eiske; Roslindale, William P. Blakeslee; Salem, Dorothy E. Snyder; Sherborn, Riehard T. Darby; South W ellfleet, Wallaee Bailey; West Medford, Dr. and Mrs. O. Sewall Pettingill, Sr.; West Newton, Mr. and Mrs. Frank 0. Howard. From Michigan: 1 — Ann Arbor, James Howell. From Minnesota: 4 — Duluth, Mr. and Mrs. Joel K. Bronoel, Dr. and Mrs. P. B. Hofslund. From New Hampshire: 49 — Campton, Gordon E. Davis; Concord, Mrs. Robert Dyment, Mrs. Charles Gallagher, David Mann, Betty Steele; Dunbarton, Mrs. Wileox Brown, Jane Grant; Durham, Mrs. May Berry, Constance Casas, Lorus J. Milne, Riehard Yelle; East Andover, L. C. Rising; Greenland, Ruth Gamester; Hanover, Evelyn Hanson, Erika Parmi, Mr. and Mrs. Edwin Sherrard; Hill, Dana Charles; Hollis, Mr. and Mrs. Tudor Richards, Jeff Smith; Intervale, Mr. and Mrs. Stephen Lawrent; Jackson, Jeannette E. Graustein, Mr. and Mrs. James R. Warren, Fern Yates; Jaffrey Center, Mr. and Mrs. Norman Torrey; Laconia, H. Cook Anderson; Lisbon, Harold H. Blanehard; Littleton, Robert Bradley, Harry MeDade, Kathleen McDade, John Mcllwayne; Manchester, Mrs. Robert Booth; Meredith, Alex Lineoln; Monroe, Mrs. Lois Cole; New Hampton, Vera Hebert, Pauline Merrill, Robert W. Smart; Newport, Mr. and Mrs. Sterling Brackett; North Hampton, Sue Fowler; Plymouth, Julia M. Stark; Portsmouth, Irene Garland; Rye Beach, Flope Wright; Silver Lake, Joan A. Watt; Whitefield, Mrs. Walter Bradley. From New Jersey: 16 — Denville, Anne Benton; Jamesbiirg, Jeff Swinehroad; Madison, F. H. Clenny; Maplewood, Otto Brief; Morristown, Jack Stewart; Mountainside, Mr. and Mrs. Albert Schnitzer; Newfoundland, Mr. and Mrs. Frank P. Townsend; Orange, Anne W. Wachenfeld; Ramsey, Eleanor Dater; Roselle Park, Dorothy 368 THE WILSON BULLETIN Sei>temher 1967 Vol. 79, No. .3 lirowne; Tenajly, Dr. and Mrs. Dean Amadon; Trenton, Kenneth W. Prescott; Wenonuh, E. R. Manners. From New York: 26— Allegany, Dr. and Mrs. Stephen W. Eaton; Amherst, Richard Brownstein; Buffalo, Joanna Burger; Center Moriches, Mr. and Mrs. Theodore Chase Jr.; Hopewell Junction, Davis Finch; Ithaca, Stephen T. Emlen, Lawrence Grinnell, William T. Keaton, Douglas A. Lancaster, Dr. and Mrs. O. .Sewall Pettingill, Jr., Samuel Weeks; New York City, Charles T. Collins, Robert Dickerman, C. Stuart Keith, Richard L. Penney, Richard L. Plunkett; Bye, Devin A. Garrit\ , St. Bonaventure, David Krieg; Solvay, Mr. and Mrs. Donald S. McChesne\ ; Tappan, Lester Talkington; W'illiamsville, Mr. and Mrs. Harold D. Mitchell. From Ohio: 18 — Bowling Green, Elden W. Martin; Burton, Robert McCullough; Canfield, Mr. and Mrs. G. William Richter; Chardon, Marjorie Ramisch; Cincin- nati, Rod Crafts; East Liverpool, Mr. and Mrs. John T. Laitsch; Gambler, Robert I). Bevins, E. Ray Heithaus; Girard, Mr. and Mrs. H. 0. Heimerdinger ; Kent, Dr. and Mrs. Ralph W. Dexter, Mr. and Mrs. Alex Warner; Lakewood, Mr. and Mrs. William A. Klamm. From Oklahoma: 1 — Norman, George M. Sutton. From Peiinsvlvania: 26-Chester Springs, Phillips B. Street; Dunmore, Elizabeth A. Taft; Fort Washington, Mr. and Mrs. Edward L. Altemus; Harrisburg, Donald S. Heintzelman; Narberth, Paul A. Livingston; Newton, Mr. and Mrs. Lester S. Thomas; Philadelphia, C. Chandler Ross, Mr. and Mrs. Gene Stern, Mr. and Mrs. W'arren E. Swank; Pittsburgh, Dr. and Mrs. Kenneth C. Parkes; Selinsgrove, Mr. and Mrs. George C. Boone; Sheffield, Mr. and Mrs. Charles A. Neel; State College, Blanche M. Bordner, Dorothy L. Bordner; Trout Run, Mr. and Mrs. Walter K. Bigger; Willow Grove, John Knichen; Wycombe, Mr. and Mrs. Alan Brady. From Rhode Island: 2— Jamestown, Mrs. Allen Davenport; Warwick, Mrs. Kenneth Kinsey. From South Carolina: (,-Chester, Mrs. J. H. McClure, Mrs. ■«'. Cornwell Stone, Sr.; Travelers Rest, Charles Gilreath, Liz Gilrealli, M. Ruth Gilreath, Winnie Gilreath. From Tennessee: S^GatUnburg, Mr. and Mrs. .\rthur Stupka; Maryville, Ralph Zaenglein. From Vermont: 2— Londonderry, Mrs. James R. Downs; Lyndonville, Donald Mdler. From Virgina: Y—Ashburn, Mrs. Herbert M. Church; Scottsville, Caroline L. White- side; Williamsburg, Mr. and Mrs. Paul S. Baker. From West Virginia: 6— Huntington, Ralph M. Edeburn; Morgantown, Mr. and Mrs. Maurice Brooks; Dr. and Mrs. George A. Hall; St. Albans, George F. Hurley. From Wisconsin: 1 — Margarette E. Morse. From Washington, D.C.: 3— Richard C. Banks, Charles A. Ely, Roxie C. Laybourne. From Bermuda: Hamilton, David B. Wingate. From Manitoba, Canada: 1 — Obodo, A. D. Herbert. From New Brunswick, Canada: 2— St. John, Mr. and Mrs. W. Austin Squires. From Nova Scotia, Canada: \— Halifax, Ian A. McLaren. From Ontario, Canada: M-Burlington, W. John Richardson; Guelph, M. I. Dyer; Kingston, J. Allen Keast; Toronto, William W. H. Gunn. Addresses Unknown: 14— Mr. and Mrs. Carlyle Burland, Alexander Davis, Mr. and Mrs. Harold Flanders, Murray E. Haight, Mr. and Mrs. J. Chester Littlefield, Martin Michener, Richard Missellis, Mrs. Ernest B. Neel, Mr. and Mrs. David Ochsner, Lee Snyder. This issue of The W'ilson Bulletin was published on 30 September 1967 n, ■, TIieWlsotiBullettn PUBLISHED BY THE WILSON ORNITHOLOGICAL SOCIETY WEST VIRGINIA U. • MORGANTOWN, W. VA. VOL. 79, No. 4 DECEMBER 1967 PAGES 369-489 The Wilson Ornithological Society Founded December 3, 1888 Named after ALEXANDER WILSON, the first American Ornithologist. President — Aaron M. Bagg, Farm Street, Dover, Massachusetts. First Vice-President — H. Lewis Batts, Jr., Dept, of Biology, Kalamazoo College, Kalamazoo, Michigan. Second Vice-President — William W. H. Gunn, Apt. 1605, 155 Balliol Street, Toronto, Ontario. Secretary — Jeff Swinebroad, Dept, of Biological Sciences, Douglas College, Rutgers-The State University, New Brunswick, New Jersey. Treasurer — C. Chandler Ross, Academy of Natural Sciences, 19th and Parkway, Philadelphia, Pennsylvania. Elected Council Members — Pershing B. Hofslund (term expires 1968) ; Kenneth C. Parkes (term expires 1969); Andrew J. Berger (term expires 1970). Membership dues per calendar year are: Sustaining, $10.00; Active, $5.00. 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 $5.00 per year. Single copies, $1.25. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at $1.25 each) and may be orderd 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. Allen Press, Inc., Lawrence, Kansas LIBRARY JAN 1 9 :2e3 THE WILSON BULLEtM;=,?v A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society Vol. 79, No. 4 December 1967 Pages 369-489 CONTENTS Bird Populations of Bogs Richard Brewer 371 Fall Migration of Sharp-Shinned Hawks Helmut C. Mueller and Daniel D. Berger 397 Selection for a Delayed Simultaneous Wing Molt in Loons (Gaviidae) Glen E. W ooljenden 416 Roosting Behavior of the Herring Gull in Gentral Maine Ralph W . Schreiber 421 Variation in the Breeding Season and Clutch-size of the Robin IN Northeastern United States and the Maritime Provinces OF Canada Deborah V. Howard 432 Care, Food Consumption, and Behavior of Bald Lagles Used in DDT Tests Nicholas J. Chura and, Paul A. Stewart 441 General Notes GOSHAWK PREDATION ON SHARP-TAILED GROUSE IN THE NEBRASKA SANDHILLS Lawrence J. Bias 449 REGURGITATION BY KILLDEER AS A POSSIBLE MEANS OF DISPERSAL OF SEEDS AND AQUATIC ORGANISMS Victor L. de Vlaming 449 MOURNING DOVE EGG IN NESTS OF CATBIRD AND ROBIN Larry C. Holcomb 450 OVERLAPPING NESTINGS BY A PAIR OF BARN OWLS Peter L. Ames 451 A POSSIBLE CASE OF EGG TRANSPORT BY A CHUCK-WILL’s-WIDOW Denzel E. Ferguson 452 NEST SITE MOVEMENTS OF A POOR-WILL Raymond N. Evans 453 THE AMPIIIRHINAL CONDITION IN THE PASSERIFORMES J. Alan Feduccia 453 A COMMON CRACKLE LEARNING TO SOAK BREAD A. L. Rand 455 PREALTERNATE MOLT IN THE SUMMER TANAGER Kenneth C. Rarkes 456 The President’s Page Aaron M. Bagg 459 Ornithological News 460 Annual Report of The Conservation Committee Roland C. Clement 461 Ornithological Literature W. Earl (/odfrey, The Birds of Canada, reviewed l)y Cieorge M. Sutton; Dorotliy E. Snyder, The Birds of Guyana {formerly British Guiana), reviewed by E. Haversclimidt ; Alfred Stefferud (Ed.), Birds in Our Lives, reviewed by (ieorge A. Hall; .James Fisher, The Shell Bird Book, reviewed by Olin .Sewall JAttingill, Jr.; David Lack, Population Studies of Birds, reviewed by Cameron B. Kepler. Index to Volume 79, 1967 Mildred Stewart and Tanya Hall 172 BIRD POPULATIONS OF BOGS Richard Brewer Bogs throughout the glaciated region of the northern hemisphere show considerable uniformity in structure and composition (Curtis, 1959). In the southern portion of this region, bogs form “boreal islands” with a high percentage of species of northern affinities and are regarded as relicts of former conditions associated with Pleistocene glaciation (Bailey, 1896; Transeau, 1903). These statements are fair conclusions based on numerous floristic and vegetational studies. Faunal studies are fewer and, as a con- sequence, such questions as the degree of uniformity of species composition and geographical affinities among bog animals are unresolved. As a con- tribution toward answering such questions, bird populations in two bogs in southwestern Michigan were studied and analyzed in conjunction with the existing published information on avian populations of eastern North American bogs. STUDY AREAS One study area (Portage Bog) consisted of a 16.5-acre tract of sphagnum-leatherleaf- tamarack bog with sides of 600 and 1200 feet. Located south of Portage in Kalamazoo County (NE Sec. 28, R 11 W, T 3 S), it is part of a much larger area of similar peatland about one-quarter-mile wide and one and one-half miles long. The study area is surrounded on all sides by similar vegetation but about 150 feet to the southwest and roughly parallel to one side runs a drainage ditch 12 feet wide. Beyond the ditch is deciduous thicket or forest on thin peat or mineral soil. The study area was located wholly on deep peat (17 feet). Six physiognomic vegetation types occurred in a fairly complex mosaic. Open wet bog made up about 0.3 acre; open dry hog (Fig. 1), 8.7; low thicket, 0.9; high thicket (Fig. 2), 4.7; parkland, 0.8; and tamarack forest, 0.9. The second study area (Sugarloaf Bog, Fig. 3) consisted of a strip 100 X 1000 feet (2.3 acres) in 1965 and 200 X 1000 feet (4.6 acres) in 1966 running down the center of a red maple-yellow hirch-white pine hog forest fringing Sugarloaf Lake southwest of Portage in Kalamazoo County (Sec. 32, R 11 W, T 3 S). The hog forest was 300-600 feet wide and lay between an upland oak-pine forest and an expanse of open hog 100 300 feet wide adjacent to the lake. Elevation of both study areas was 850-60 feet above mean sea level. Botanical features of both areas and a vegetation map of Portage Bog are given in Brewer (1966). METHODS Breeding bird populations were studied by the standard spot-map method (Williams, 1947). Establishment of census plots was careful, using a Brunton pocket transit and steel tape. Because of the strip-like nature of the Sugarloaf Bog plot, virtually no territories lay wholly within it and, therefore, estimation of the fraction included was 372 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Fig. 1. General view in Portage Bog showing expanse of open bog with a narrow zone of high tamarack thicket fringing a strip of tamarack forest (canopy height 20-40 feet). The only noticeable plants are leatherleaf and tamarack. (Sept. 1965) one source of error. This error is also present when using plots of more standard dimensions because, except when plots are very large, most territories include some area beyond the boundaries. At Portage Bog, for example, only about one-third of the total number of Song Sparrow territories touching the plot lay wholly within the 16.5 acres. Coverage of Portage Bog included six breeding seasons as follows: 1961 (9 trips, 1 May-21 August; total hours 17), 1962 (4, 10 April-24 July; 8.5), 1963 (7, 4 May- 17 August; 15), 1964 (7, 20 May-22 July; 10.5), 1965 (9, 22 April-24 August; 17), and 1966 (12, 11 April-30 July; 37). Most censuses were in the forenoon, usually beginning after 6 and before 9 and lasting about two hours. Visits to the tract for other purposes provided corroborative observations beyond the time spent in formal censusing. Although the results for 1962 are believed to he generally correct, less confidence can be placed in them compared with other years because of the sparseness of coverage. Less attention was paid to the area outside the breeding season, hut 20 additional trips totaling 55 hours were made (September, 5; October, 2; November, 3; December, 6; January, 2; February, 1; March, 1), and the same field procedures of mapping locations of birds were followed. Sugarloaf Bog was censused the summers of 1965 (15 trips, 7 June-23 August; total hours 29.5) and 1966 (8, 13 May-30 June; 23.5). Kichanl Brewer BIRD POPULATIONS OF BOGS 373 Fig. 2. The denseness of the extensive high thickets is indicated hy this photograph taken just outside one. The pale spot to the left of center is the jacket worn hy a person standing about six feet inside the thicket. (Sept. 1965) BREEDING BIRD POPULATIONS AT PORTAGE BOG Twenty-four species occurred regularly during at least one of the six breeding seasons; however, the average annual number of breeding species was only about 16 (Table 1). Density was about 170 pairs per hundred acres. In interpreting this and other estimates of density, the limits to the precision of the spot map method (see, e.g., Breckenridge, 1955:410), especially lor species not showing Type A territories (Nice, 1941) and those with very large territories need to be borne in mind. The only species in these groups which seemed of moderately high density here was the Brown- headed Cowbird.^ For this species the largest number of males seen together in June was assumed to represent the number frequenting the area; density was taken as one-half this number on the assumption that most of the cowbirds had some portion of their home range outside the tract. The reader may decide for himself the limits of precision of this estimate. Song Sparrows were by far the most abundant species, having an average density of 9.4 territorial males (57 per 100 acres). The only other species ^ Scientific names of birds are given in Table 3 or, for species not in Table 3, where they are first mentioned. 374 THP: WILSON BULLETIN Docenilx-r 1967 Vol. 79, \o. 4 Fig 3. Sugarloaf Bog, looking toward the lake. Canopy height is 65-80 feet. Cinnamon fern is noticeable on the hummocky surface. The shrub at left is spice liush. ( Sept. 1965) having an average density greater than 10 per 100 acres were Yellowthroat, Field Sparrow, Rufous-sided Towhee and, perhaps. Brown-headed Cowbird. The Yellow Warbler was present the first two years and virtually absent thereafter ( although it continued to occur elsewhere in the bog ) . The Traill’s Flycatcher (evidently Empidonax brewsteri Oberholser, according to Stein’s diagnosis, 1963 ) was absent the first two years and present three of the last four. Both species were birds of the thicket areas, and it may be that between 1961 and 1963 conditions became unfavorable for the warblers and favorable for the flycatchers. The most prominent change was an increase in high thicket at the expense of low thicket. Possibly the same successional trend was responsible for the appearance in 1965 of the Nashville Warbler, a northern species not previously known to nest in southwestern ^lichigan (Brewer and Raim, 1966). Neither Black-capped Chickadees nor Yellow-shafted Flickers had a nest on the study area. Tamaracks were the only dead trees of any size, and they seemed not to decay in a way that rendered them suitable for excavation by cavity-nesting birds. The scarcity of such species is evident. Both chickadees and flickers may have nested in hardwoods adjacent to the bog and used Kil-liard Brewer BIRD POPULATIONS OF BOGS 375 Table 1 Breeding Bird Populations of Portage Bog (Males) Species 1961 1962 1963 1964 1965 1966 Mean, all years Males/100 acres Song Sparrow 9.5 8.0 10.1 9.8 10.2 8.5 9.4 57 Yellowthroat 3.8 5.6 3.8 5.3 3.4 4.9 4.5 27 Field Sparrow ( Spizella pusilla) 1.1 4.0 2.4 3.0 2.4 1.2 2.4 14 Rufous-sided Towhee 2.2 2.1 1.7 4.1 1.6 3.0 2.4 14 Brown-headed Cowbird + + + + + + 2.4 14 Catbird 1.0 1.2 1.2 2.1 2.0 1.5 1.5 9 Am. Goldfinch + + + + 1 1 >0.3 6 Traill’s Flycatcher 0 0 2.0 1.4 1.1 0 0.8 5 Yellow Warbler 2.3 0.8 0 0 0 + >0.5 3 Black-capped Chickadee + + + + + 0.9 >0.2 3 Mourning Dove + 0 + + + + + 3 Cedar Waxwing + + + + + + + 3 Yellow-shafted Flicker + + + + + + + 2 Cardinal 0 0 0 0.8 0.9 0.9 0.4 2 Brown Thrasher 0 0.9 0 + 0.5 0.6 >0.3 2 Ruby-throated Hummingbird {Archilochus colubris) 0 0 0 19 0 0 0.2 1 Nashville Warbler 0 0 0 0 0.9 0 0.2 1 Mallard (Anas platyrhynchos) 1 nest 0 1 nest + 1 nest -f- + + Marsh Hawk + + 0 0 0 + + + Eastern Bluebird iSialia sialis) + 0 0 0 0 0 + + Tree Swallow + 0 0 0 0 0 + + Robin 0 0 0 0 + + + + Whip-poor-will ( Caprimulgus vociferus) 9 9 9 ? + 9 + + Veery 0 0 0 0 0 + + + No. species No. males 16 13 13 16 18 18 16 >25.1 >166 + indicates present on tract but density low or difficult to assess. the tract only as a part of their feeding range. A possible indication of the rarity of suitable nest holes within the bog was the use of the same cavity in a dead pine just off the tract by bluebirds in May 1961 and Tree Swallows in June. I believe that Robins also placed their nests in deciduous areas and came into the bog only for feeding. There were substantial differences in the utilization of different vegetation types by certain species. To place this on a quantitative basis, numbers of territories were calculated for the eastern portion of the bog ( 8.7 acres ) which was predominantly open and for the western portion (5.1 acres) which was predominantly low and high thicket. The year 1962 was omitted because 376 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 the small number of sightings for each territory made approximation of percentages in different vegetation types impossible. The average figures for five years indicate slight preferences by Eield Sparrow for open bog and Song Sparrow for thicket and rather strong preferences by towhee, Yellowthroat, and Catbird, for thicket. The number of species occurring regularly during at least one year in open bog was about 13 and in thicket about 21; densities were less than 100 males per 100 acres in open bog and well over 200 males per 100 acres in thicket. Several differences between 1964 and other years appeared related to a fire which that spring burned areas on each side of the drainage ditch along one edge of the tract, although not reaching the tract itself. The immediate result of the fire was a reduction in woody growth followed by plentiful root sprouting of aspens. Changes in density considering the whole tract between 1963 and 1964 were not particularly striking, but the distribution of territories was. Song Sparrows were virtually absent from the areas ( open bog) adjacent to the burn, with the result that the number of territories in open bog dropped from 6.4 in 1963 to 3.4 in 1964. An increase from 1.2 to 4.0 in thicket compensated for the decrease in open bog. Towhees used the burnt area much more extensively than in other years, so that portions of 3 territories included open bog whereas only the edge of 1 territory did so in most years. Similar trends of increased density in open bog for 1964 were seen in Yellowthroat and Eield Sparrow. Breeding season visitors to the bog were infrequent. Probably most represent birds making an occasional trip beyond their usual limits or adults, young, or family groups that moved away from their nest area following nesting. The only species that visited the bog in numbers were the Blue Jay and the Robin. Blue Jays were frequently seen in the bog until late May; then they were almost entirely absent until early August at which time they again began to visit the bog regularly. Robins were essentially absent from the bog during winter and also during the peak of the breeding season ( except in 1965 and 1966, when one pair included a part of the bog in its breeding territory ) . They were occasionally seen during spring, but it was only during blueberry season that they were common. With ripening of the berries, both adults and young swarmed into the area. On 11 July 1964, I plotted 18 individuals and twice that number would be a conservative estimate of the birds present during the two-hour census. It is my impression that some of the visitors were surplus single birds seeking to set up territories or pairs searching for a suitable area for nesting, possibly following a nest failure. In the latter category might fall Eastern Meadowlarks which I three times saw in the open portion of the bog. On 25 June 1963, I saw two meadowlarks, one with what I took to be nesting Kic-liard i5rewer BIRD POPULATIONS OF BOGS 377 Table 2 Breeding Bird Populations of Sugarloaf Bog (Males per 100 acres) Species 1965 1966 Mean Black-capped Chickadee 39 41 40 Ovenbird 4 72 38 Wood Pewee 24 28 26 Blue Jay 28 15 22 Cardinal 28 13 20 Scarlet Tanager 24 11 18 Downy Woodpecker 22 11 16 Red-eyed Vireo 17 15 16 Great Crested Flycatcher 13 17 15 Song Sparrow 26 0 13 Tufted Titmouse 4 13 8 Rufous-sided Towhee 17 + >8 Wood Thrush 13 0 6 Yellow-throated Vireo (Vireo jlavijrons) 0 11 6 Hairy Woodpecker 9 0 4 Yellow-shafted Flicker 6 2 4 White-breasted Nuthatch + 6 >3 Black-throated Green Warbler 6 0 3 Catbird 4 0 2 Common Crackle + 0 + Veery + + + Ruffed Grouse + + + Yellowthroat + 0 + Owl ( Barred ? ) ( Strix varia ? ) + 0 + Wood Duck (Aix sponsa) 0 + + Brown-headed Cowbird 0 + + Number of species 23 18 20 Number of males >284 >255 >270 + indicates present on tract but density low or difficult to assess. material in its beak, sit for more than 20 minutes on a dead tamarack. The speculation is worth entertaining that the physiognomy of open bog is close enough to that of open fields that in hunting for nest-sites the species may occasionally be misled. It is evident that the avifauna of Portage Bog has little of a boreal nature about it. To provide an objective standard for determining geographical affinities here and in subsequent sections, I have used the analysis of Udvardy (1963) in which he erects 17 faunal groups each composed of North American passerine species “whose ranges are similar and more or less overlapping. Most of them also stand well as ecological entities.” In making 378 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 use of Udvardy’s analysis, two additional categories were necessary: an unanalyzed element, consisting of several species of wide geographical range which Udvardy did not assign to faunal groups and non-passerine species, which also tend to have extensive geographical ranges and which Udvardy did not treat. Eor Portage Bog, the unanalyzed element was hy far the most important, making up 42 per cent of the species; next most important were non-passerine species (25 per cent). This agrees with the frequent observation (e.g., Odum, 1945:198) that geographically wide-ranging species are important in early serai stages. Species of the eastern deciduous forest, boreal forest, and eastern ecotone faunas were all about equally well represented ( 12, 12, and 8 per cent ) . In terms of vegetational affinities, the avifauna is forest edge. The species list is scarcely different from that to be expected on a southwestern Michigan moist thicket area having a wholly different flora of, for example, willows, brambles, and goldenrod. This conclusion supports the view that phys- iognomy or structure of vegetation is important in the community distribu- tion of birds (Odum, 1945; Kendeigh, 1948). BREEDING BIRD POPULATIONS AT SUGARLOAF BOG Twenty-six species occurred as breeding birds during one of the two summers. The average number of species per year was about 20, or four more than at the 16.5-acre Portage Bog, and the density was about 270 males per 100 acres. The Black-capped Chickadee was the most abundant species, with an average of 40 males per 100 acres (Table 2). Ten species occurred at densities greater than 10 males per 100 acres compared with four such species at Portage Bog. Nine species ( 22 per cent ) w ere common to the two tracts. Thirty-eight per cent of the species, including five of the 10 most common, were members of the eastern deciduous forest fauna. Unanalyzed and non- passerine species together made up 46 per cent, eastern ecotone species 12 per cent, and boreal forest species 4 per cent. There were notable changes in abundance between the two years. Partly this was because the tract was small; a territory shifted 200 feet could make a difference of 20 males in the calculations for 100 acres. Two changes were certainly real; these were the decrease of Song Sparrows and the increase of Ovenbirds. In 1965, the territories of five Song Sparrows lay partly on the 4.6-acre strip, mainly centered toward open bog; in 1966 no territories reached the strip. In 1965 territories of four Ovenbirds just touched the strip; in 1966 three territories were centered on the strip and three others included sizable portions of it. There was an interesting dif- Hilliarii Brewer BIRD POPULATIONS OF BOGS 379 fereiice in behavior of the Song Sparrows in Sugar loaf Bog compared with their usual habitats; they were little in evidence past late June. In such areas as Portage Bog. singing and nesting activities continue far into July and beyond. The latest nesting record for Kalamazoo County is 8 September (Batts, 1957). Most of the extension of Ovenhird territories onto the census strip occurred in the latter part of the summer after Song Sparrows had largely disappeared. An explanation for these changes lies in two possible directions: (1) the environment may have changed so that Song Sparrows were favored in 1965 and Ovenbirds in 1966, or (2) a competitive situation may exist in which the presence of Song Sparrows prevented the occupation of the area by Ovenbirds in 1965 ( the reverse, that Ovenbirds in 1966 prevented utilization by Song Sparrows, is also conceivable ) . In favor of the first hypothesis is the fact that the other forest edge species in Sugarloaf Bog were also scarcer in 1966 than 1965. Individually all of the declines were slight (Cardinal, 1.3 to 0.6 males on the 4.6-acre strip; towhee, 0.8 to 0; and Catbird, 0.2 to 0 ) , but the decline of the whole group possibly has significance. There was, however, no evident change in the habitat except that the peat surface was slightly wetter in 1966. This would seem to favor Song Sparrows over Ovenbirds because Song Sparrows do not avoid hydric habitats, whereas Ovenbirds tend to be more common in mesic situations. Standing water also decreases the area available for nests of the exclusively ground-nesting Ovenhird. Relevant to hypothesis 2 are the following points: (a) The two species are similar enough in feeding, nesting, and singing sites that they could be competitors if they occurred together; (b) Their ecological distribution is such that only in a few communities, somewhat marginal for both, are they likely to come into contact; (c) Spring territory establishment of Song Sparrows precedes that of Ovenbirds (in southwestern Michigan mid-April or earlier compared with early May ) . If interspecific territoriality existed. Song Sparrows would have the advantage of possession; (d) Interspecific territoriality is prominent in Song Sparrows (Nice, 1943:158-161; Tompa, 1964), although I am not aware of any instances involving Ovenbirds: (e) Bog forest is probably used by both species mainly by overflow populations from more nearly optimal vegetation. The open hog and thicket areas of Portage Bog, two miles from Sugarloaf, represent nearly optimal conditions for Song Sparrows. In 1965 numbers were the highest in six years and in 1966, the second lowest (Table 1). It is possible that population changes in optimum habitats are only a very subdued reflection of actual population 380 THE WILSON BULLETIN Deceniher 1967 Vol. 79, No. 4 changes (Brewer, 1963; Kluyver and Tinbergen, 1953); it is perfectly feasible that there were substantial surplus sparrows in 1965 and few or none in 1966. It is hoped that observations during territorial establishment will allow a choice between the two hypotheses. In a sense the presence of Ovenhirds and Song Sparrows in Sugarloaf Bog depends on adjacent vegetation types. This was also true of Yellow- throats, which had high populations on the hog mat and occasionally extended their activities as far as the census strip. The Acadian Flycatcher ( Empidonax virescens ) was an interesting contrast. Although quite common in upland forest, including the part immediately adjoining the hog forest, it seemed never to penetrate the hog forest more than five or ten feet, and that only rarely. Estimation of population size was difficult for the Veery. It sang steadily on the border between bog forest and open bog ( about three males ) , rarely on the border between bog forest and upland forest, and almost never within the bog forest. I suppose that territories may extend across the hog forest, hut I have not tried to estimate density. About one-third of the breeding species and individuals were hole-nesters. This is probably related to the large number of dead elms ( of Dutch elm disease) and yellow birch suitable for excavation. OBSERVATIONS AT PORTAGE BOG OUTSIDE THE BREEDING SEASON The mean number of species recorded per visit during June and July was 10. For August it was slightly less, 9; but about the end of August there appears to be a rapid exodus from the bog so that the mean number for September and October is 5. The sparseness of the bird population in the bog at this time compared with the deciduous areas near it is quite notice- able. Most of the prominent birds of the bog, towhee. Song Sparrow, Yellow- throat, Catbird, are still to be found in numbers in the aspens and bog birches along the drainage ditch when they are virtually absent from the census tract. Of several possible explanations, a post-breeding emigration into different vegetation types seems most likely; why this would occur is not evident. Winter populations were low; on two December trips of about an hour each, no birds were seen on the census plot. The average number of species seen per trip was 2 for November, less than 1 for December, and slightly more than 1 for January-March. Only Blue Jay (seen on 5 trips). Black- capped Chickadee (4), and Eastern Goldfinch (2) occurred on more than one of the 13 winter trips. Kicliard Brewer BIRD POPULATIONS OF BOGS 381 The extreme sparseness of the bird population in winter is probably related to a poor food supply, although the flatness of the peatland, resulting in lack of protection from wind, may also be involved. It is evident from an examination of tbe list of plant species present in Portage Bog (Brewer, 1966 ) that fruits and seeds are not likely to be in good supply in the winter. Tamarack, which might be thought to provide a fairly rich supply, sheds its seeds in the autumn. Duncan (1954) found that in Minnesota about 97 per cent of tamarack seeds had fallen before 31 October. I have no direct evidence that invertebrates are scarcer in bogs than elsewhere in winter, but in view of the substantial amount of energy that becomes tied up in peat and thus does not become available to other trophic levels, this seems a reasonable possibility. BREEDING BIRD POPULATIONS OF EASTERN NORTH AMERICAN BOGS Ecological and zoogeographic relationships of bogs were studied by means of compilations including previous studies. Both censuses and studies giving lists of characteristic species for a particular area were used. All such studies that I am aware of were included except those conducted on areas of heterogeneous vegetation or on excessively small and isolated areas. The study areas were grouped into open bog (8 areas), thicket (8), and forest (17) using physiognomic criteria. Forests were further classified into those of pure or nearly pure tamarack, those with spruce as a dominant or co-dominant, those with cedar as a dominant or co-dominant, and those with both coniferous and broad-leaved trees important. Tbe specific areas used were as follows: Open Bog — Martin (1959, 1960), wet bog and dry bog; Jackson (1914), sedge and Cassandra associations; LeFebvre (1959), open sedge mat; Root (1942), bog mat association; Aldrich (1943), Chamaedaphne calyculata consocies; and open wet and dry areas of Portage Bog. Thicket — Buckner and Turnock (1965), Plot II; LaFebvre (1959), bog birch; Root (1942), lowland thicket and dead tree associations; Aldrich (1943), Neinopanthus- Alnus association; Stewart and Aldrich (1952), scrub black spruce bog and bog shrubs; Robbins and Stewart (1951), scrub spruce bog; and high and low thickets of Portage Bog. Tamarack Forest — Buckner and Turnock (1965), Plot I; LeFebvre (1959), tamarack; Goodwin and Jarvis (1964), Fairfield, Jarvis, and Woodford (1960), tamarack swamp; and tamarack forest of Portage Bog. Spruce Forest — Jackson (1914), tamarack-black spruce association; Walkinsbaw (1949), black spruce-tamarack bog; Martin (1959, 1960, and pers. comm.), Picea mariana and P. mariana-Thuja forests; Stewart and Robl)ins (1951), virgin spruce- hemlock bog forest. Cedar Forest — Breckenridge (1955), bog forest habitat; Jackson (1914), cedar- balsam-bemlock association; Root (1942), cedar bog association; Kendeigb (1948), 382 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Table 3 Pkhckntage Fhe(,)uency of Occurrence (and Maximum Density) in Types Bog Vi:getation Species Open bog Thicket Tamarack forest Spruce forest Cedar forest Mixed forest American Bittern ( Botaurus 38 25 0 0 0 0 lentiginosus ) Marsli Hawk (Circus cyaneus) 38 12 25 0 0 0 Ruffed Grouse (Bonasa umbellus) 0 0 25 20 67 40 Virginia Rail (Rallus liniicola) 25 0 0 0 0 0 Sora {Forzana Carolina) 38 0 0 0 0 0 Mourning Dove (Zenaidura macroura ) 12 25 50 20 33(11) 20 Yellow-shafted Flicker (Colaptes 25 62 50 80 50 80 auratus) Pileated Woodpecker {Dryocopus 0 0 0 20 50 40 pileatus ) Yellow-bellied Sapsucker 0 12 25 20 17 20 iSphyrapicus varius) Hairy Woodpecker i Dendrocopos 0 38 0 20 67 60 villosus) Downy Woodpecker i D. puhescens) 0 38 0 0 17 60(16) Eastern Kingbird ( Tyrannus 50 25 25 0 33 0 tyrannus) Great Crested Flycatcher 0 25 25 20 50(14) 80(15) i Myiarchus crinitus) Eastern Phoebe iSayornis phoehe) 0 25 50 0 0 0 Yellow-bellied Flycatcher 0 25 25 60(22) 33(22) 0 ( Empidonax flaviventris) Traill’s Flycatcher (E. traillii) 12 50 50 20 0 0 Least Flycatcher (E. minimus) 0 25 25 0 50 20 Eastern Wood Pewee iContopus 0 0 25 0 33 60(26) virens) Olive-sided Flycatcher i Nuttallornis 12 25 25 40 33 0 borealis) Tree Swallow (Iridoprocne bicolor) 38 25 0 0 0 0 Barn Swallow^ (Hirundo rustica) 25 0 0 0 0 0 Blue Jay iCyanocitta cristata) 12 25 25 60 67 80(22) Common Crow ( Corvus brachy- 0 0 0 40 17 60 rhynchos) Black-capped Chickadee ( Parus 25 75 75(13) 60 100(19) 100(40) atricapillus) White-breasted Nuthatch (Sitta 0 0 0 0 33 40 carolinensis) Red-breasted Nuthatch (S. cana- 0 0 25 60 84 20(12) densis) Brown Creeper (Certhia familiaris) 0 0 25 40 33 20(12) House Wren (Troglodytes aedon) 0 25 0 0 17 20 Kicliard Brewer BIRD POPULATIONS OF BOGS 383 Table 3 [Confd ) Species Open bog Tamarack Thicket forest Spruce forest Cedar forest Mixed forest Winter Wren {T. troglodytes) 0 0 25 80 50 20 Catbird i Dumetella carolinensis) 12 50(11) 50 20 17 60 Brown Thrasher [Toxostoma rujum) 0 25 25 0 17 0 Robin {Turdus migratorius) 0 38(11) 75 0 33 40(14) Wood Thrush [Hylocichla 0 0 0 20 33 80(13) mustelina) Hermit Thrush {H. guttata) 0 38(19) 25 40 17 20(21) Swainson’s Thrush iH. ustulata) 0 25(14) 25 60 17 20 Veery (//. fuscescens) 0 25 25(18) 20 84(18) 80 Golden-crowned Kinglet (Regulus 0 12 25 100(32) 50(15) 40(32) satrapa) Cedar Waxwing iBombycilla 38 62(11) 75(27) 60 67 20 cedrorum) Red-eyed Vireo ( Vireo olivaceus) 12 12(42) 50(16) 0 50 60(16) Black-and-white Warbler (Mnio- 12 25(11) 50 60 67(19) 60 tilt a varia) Tennessee Warbler {Vermivora 0 25(22) 25 0 17 20 peregrina) Nashville Warbler ( V. ruficapilla) 0 62(39) 100(55) 60(28) 100(28) 40 Parula Warbler {Parula americana) 0 0 25 0 50 40 Yellow Warbler {Dendroica 0 50(10) 25 20 0 0 petechia) Magnolia Warbler (Z). magnolia) 0 38(33) 25 100(40) 50(27) 60(40) Myrtle Warbler iD. coronata) 12 38 25 60 50 20 Black-throated Green Warbler 0 0 0 20 33(18) 40(26) {D. virens) Blackburnian Warbler iD. fusca) 0 38(39) 25 60(96) 67(13) 60(96) Chestnut-sided Warbler iD. 12 38 0 20 33 0 pensylvanica ) Ovenbird iSeiurus aiirocapillus) 12 0 0 0 50 60(38) Northern Waterthrush (S. 0 25(33) 25 60(64) 33 60(64) noveboracensis) Yellowthroat iGeothlypis trichas) 75(134) 100(55) 100(32) 60(26) 50(29) 60(13) Canada Warbler ( Wilsonia cana- 0 38(22) 50 60(44) 50(12) 60(44) densis ) Red-winged Blackbird (Agelaius 75(12) 12 25 0 0 0 phoeniceus) Common Crackle ( Quiscalus 25 0 0 0 0 20 quiscula) Brown-headed Cowl)ird i Molothrus 25 25(25) 50 0 17(13) 40 ater ) Scarlet Tanager i Piranga olivacea ) 0 12 25 40 67 80(18) Cardinal i Richmondena cardinalis) 12 12 50 0 0 40(20) 384 THE WILSON BULLETIN December 1967 Vol. 79, No. I Table 3 ( Cont\l ) Species Open bo>^ Tamarack Thicket forest Spruce forest Cedar forest Mixed forest Kose-ljreasted Grosljeak \Fheucti- 0 12 50 0 17 20 cus ludovicianus ) Purple Finch ( (.arpodacus 25 50 50(15) 60 50 20 purpureus} American Goldfinch iSpinus tristis) 25 12 50 20 17 20 Rufous-sided Towhee iPipilo 25 50(24) 25 0 17 20 eryth ro ph th (dm u s ) Slate-colored .lunco ijunco hyemcdis) 0 38(13) 0 80 50 20(14) White-throated Sparrow iZono- 0 38(61) 50(39) 80(62) 100(48) 40(14) trichia albicollis) Swamp Sparrow ( Melospiza 75( 176) 50 50 20 17 20 georgiana) Song Sparrow (17. melodio) 75( 51 ) 88(63) 75 20 50 40(13) cedar-lialsam forest; Martin (1959, 1960, and pers. comm.j, F. mariuna-Thuja forest; Stewart and Aldrich ( 1952 ) , white cedar-tamarack-hlack ash hog forest. Mixed Coniferous-Deciduous Forest — Sugarloaf Bog; Aldrich (1943, also 1939), Larix-Acer Betula association; Stewart and Aldrich (1952), white cedar-tamarack- hlack ash hog forest; Smith (1938, 1941, 1943, 1944, and 1945), halsam-hlack ash hog; Stewart and Robbins ( 1951 ) , virgin spruce-hemlock hog forest. Community relationships. — The categories given above (and in Table 3) are of descriptive value but otherwise have no fundamental significance. The breeding birds of one open bog are not greatly like those of another; the avifauna of one spruce forest is rather like that of another, but it may be equally similar to that of a cedar forest or a spruce thicket. If we attempt to determine in what vegetation types the peaks of occur- rence for various species fall, they appear to be equally scattered through the whole series from open bog to mixed forest (Table 3l. If we pursue the matter, however, by preparing other lists for pure deciduous forest in the same geographical areas, non-bog spruce-fir forest, etc., it becomes evident that the peaks of occurrence tend to fall into four groups correspond- ing to marsh, thicket or forest edge, spruce-fir forest, and deciduous forest. The species which seemingly peak at tamarack forest, between spruce and cedar bog, etc., virtually all have still higher peaks in one of these four types. If we recognize these four ecological groups ( which appear to cor- respond to the biociations and biocies of Kendeigh, 1948 ) we can make the following statements: Richard Brewer BIRD POPULATIONS OF BOGS 385 (1) The avifauna of open wet bogs is not closely related to other bog types, being made up of wide-ranging marsh species such as rails, American bittern. Red-winged Blackbird, and Swamp Sparrow. ( 2 ) Open dry bogs are depauperate forest-edge communities possessing those species able to exist with a minimum of taller woody growth ( e.g.. Song Sparrow, Yellowthroat ) . ( 3 ) The avifauna of thickets is a conglomeration of species, mainly forest- edge (such as Yellow Warbler, Traill’s Flycatcher, Rufous-sided Towhee) but also with species from adjacent forests (e.g.. Downy and Hairy wood- peckers, Hermit Thrush, and several warblers ) . (Tj Bird populations of tamarack forests are likewise conglomerations of thicket and forest species. The species that within the bog sequence reach their peak of frequency in tamarack forest ( e.g., Phoebe, Brown-headed Cowbird, Rose-breasted Grosbeak, American Goldfinch) are probably all still more frequent in some non-bog vegetation. ( 5 I Spruce bog populations are composed primarily of spruce-fir forest species such as Yellow-bellied Flycatcher, Swainson’s Thrush, Golden-crowned Kinglet, Hermit Thrush, Myrtle Warbler, Winter WYen, Magnolia Warbler, Brown Creeper, Purple Finch, and Slate-colored Junco. There are few very striking differences in species composition between spruce bogs and mature spruce-fir forests on non-peat sites. The Olive-sided Flycatcher is perhaps more apt to occur in spruce bogs, and the Solitary Vireo ( Vireo solitarius ) , Cape May Warbler [Dendroica ti^rina), and Bay-breasted Warbler [D. castanea ) are probably more frequent in spruce-fir forests. (6) Cedar forests share species of spruce-fir forest (e.g.. Winter Wren, Yellow-bellied Flycatcher, Slate-colored Junco, Purple Finch) and deciduous forest (e.g.. Hairy Woodpecker, Wood Pewee, White-breasted Nuthatch, Red-eyed Vireo). (7) Mixed forests likewise have birds both of spruce-fir and deciduous forest, with the latter more prominent than in cedar forest. Virtually all of the species in the bog sequence reaching their highest frequency in mixed forest (e.g.. Wood Pewee, Ovenbird, Scarlet Tanager) have still higher peaks in pure deciduous forest. Mixed bog forests and pure deciduous, non-bog forests differ in three ways: (a) The spruce-fir species that persist at vary- ing frequencies in mixed forest are generally absent in deciduous forest. ( b ) Several forest-edge species have rather high frequencies in mixed hog forest but are scarce in pure deciduous forest. I suspect that this is related to the presence of a dense shrubby and herbaceous cover through the summer in mixed bog forest (see Brewer, 1966:44). (c) Many deciduous forest species have higher frequencies in pure deciduous forest than in mixed forest. 386 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 (o) A few species have rather obvious peaks in cedar or cedar-mixed forest and do not seem still more characteristic of pure deciduous forest or pure spruce-fir forest. These include Red-breasted Nuthatch, Black-throated Green Warbler, Parula Warbler, Black-and-white Warbler, and Veery. The first three of these Martin (1960j assigns to a hemlock forest community, ddiis may be correct; nevertheless, in comparing species lists for pure hemlock forests and hemlock-white pine-northern hardwoods forests, I see few dif- ferences other than the absence of a few species from pure hemlock. Such species as Black-and-white Warbler, Black-throated Green Warbler, Black- throated Blue Warbler, and Yellow-bellied Sapsucker appear to reach their peak frequencies in hemlock-pine-hardwood forests. This may also be the case for the Veery. The Red-breasted Nuthatch does not seem to be a member of this group; Fawver (cited in Kendeigh, 1961), in contrast to Martin (1960), found the species to be more common in spruce-fir than in hemlock. Possibly the answer is that this species is, in fact, most charac- teristic of neither of these, but cedar forest instead. A second way of looking at the community relationships of bog bird populations is this: the species present in any given stand of bog vegetation depend not only on the vegetation of that stand but also upon the geographical ranges of species able to utilize the vegetation and further upon adjacent vegetation and the birds occurring there. The latter point is particularly important in bog communities because they generally occur in relatively small patches surrounded by dissimilar vegetation. Examples have already been given in the occurrence of Yellowthroats, Ovenbirds, and Song Spar- rows in Sugarloaf Bog and in the effect of a fire in adjacent vegetation at Portage Bog. To illustrate the geographic effect, the southwestern Michigan bogs have no White-throated Sparrows for the simple reason that the south- ern limit of this species lies well to the north (however complicated the interactions of climate, physiology, etc. that set this limit). Furthermore, when it is stated that the species present in a given stand are, in part, determined by the vegetation of that stand, it is not meant that the birds select marsh, thicket, spruce-fir forest, or deciduous forest as such. Presumably they behave in habitat selection as they do in other areas of their life and tend to establish themselves in areas possessing features that act as a series of releasers for, perhaps, investigation of an area, establish- ment of a territory, etc. (Svardson, 1949). Doubtless these features are those generally associated with the presence of certain environmental factors required for the birds’ existence. In some cases we may see some fairly obvious feature such as the presence of dead trees suitable for nesting cavities with which the occurrence of certain species is correlated. Given this factor, the species may occur in stands of otherwise greatly variable vegetation. Ricliard Brewer BIRD POPULATIONS OF BOGS 387 Such observable features may be the releaser or the requisite, or both, or neither but merely some additional features associated with one or the other. The “typical” birds of a given kind of vegetation are not all of a piece. No two show exactly the same distribution when examined stand by stand. “Deciduous forest species,” for example, may be such for quite dissimilar reasons. Ovenbirds, Kendeigh (1945:428) suggests, may require broad leaves for use in nest building. Scarlet Tanagers, on the other hand, appear to require “deciduousness” rather than “broaddeavedness.” They tend to be present in bog forests with a deciduous element whether provided by broaddeaved trees or by the needledeaved but deciduous tamarack. Their dependence on deciduousness may be related to illumination in the spring. Prescott (1965) has described courtship activities involving display of the red back by males perched near the ground to females in the canopy that seem to demand good light penetration. Because the bird population of a given stand of vegetation is a product of so many factors — the geographical location of the stand, the surrounding vegetation, and a great variety of structural features of the vegetation — we cannot expect to find a given community displaying much unity. This lack of unity is both geographical, in that a given spruce bog is likely to have fewer and fewer species in common with other spruce bogs located at greater and greater distances, and vegetational, in that there is no tendency for “spruce bog” to have a well-defined group of species occurring in about the same relative numbers over the whole variety of vegetational conditions that can be contained in the term “spruce bog.” Rather we find the avian composition shifts as we move from tamarack-spruce to pure spruce to spruce-cedar or from spruce forest with small trees and openings to spruce forest of large trees and a closed canopy. The two foregoing discussions represent, I believe, the organismic and the individualistic views of communities as they can be applied to bog bird populations. Briefly, for those unfamiliar with this controversy (Curtis, 1959; Goodall, 1963; Daubenmire, 1966), the concepts differ as follows: Given a region occupied by biota, the individualistic view holds that each species occurs independently of others in those spots it is able to disperse to and survive in. Further, the conditions under which each species survives and prospers differ from those of every other species. As a consequence, the biota of a given piece of ground is simply a gathering of those species finding it within their tolerances. A usual corollary to the individualistic view is the continuum approach to describing biota: the biota is supposed to vary continuously in time and space, and each point of the continuum is equally probable. In other words, if a certain combination of species is 388 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 termed oak-hickory forest and another comliination, beech-maple forest, every intermediate between these two combinations is possible and, in fact, just as likely to occur as oak-hickory or beech-maple forest. The organismic concept regards the biota as being integrated. The emphasis is upon interactions among community associates rather than upon the responses of a single individual to its environment. As a consequence, proponents of the organismic concept generally adopt a classificatory ap- proach to the description of biota, regarding various combinations of species as being more probable than others, the “others” representing transitions. The greater probability of certain combinations is viewed as the result of activities of the community, such as production of a mature soil, development of a certain level of shading, establishment of food chains, etc. If these are fair statements of the two positions, I believe that both are, to a degree, correct. One possible area of reconciliation in the interpretation of bog bird populations is that of paleoecological history. The broad-leaved deciduous forests of eastern North America are the product of a long period of development, largely from the temperate portion of the Arcto-Tertiary Geoflora ( Braun, 1950 ) . The now extensive boreal forest is probably a product of the Pleistocene (Braun, 1950:511; Mengel, 1964:10) ; at least, there are no known Tertiary floras so heavily dominated by spruce, fir, and similar coniferous forms. The bog sere of glaciated North America is also doubtless a product of the Pleistocene, constituted of plants from a variety of pre-glacial sources. I shall suggest that the number of species typical of a certain kind of vegetation (i.e., having their peak of occurrence there ) is strongly dependent on the opportunity for species to adapt to this vegetation. Three prime con- siderations in this opportunity are (1) time of existence of the vegetation: (2) area occupied by the vegetation; and (3) the number of species already able to use the vegetation. The opportunity for adaptation to eastern decid- uous forests has been extensive because of the long period of their existence and the rather large area occupied. The opportunity for adaptation to spruce- fir forest has also been of large magnitude (as Mengel (1964) has pointed out ) , representing as it did a large area of vegetation of a kind previously unavailable. The bog communities of open wet bog, open dry bog, bog thicket, tamarack forest, and cedar forest offered much less of an opportunity for several reasons: bog communities tend to occur as small patches sur- rounded by different kinds of vegetation. They tend also to be short-lived in any one place, disappearing through successional processes. Finally, open wet bog duplicates in many structural features the ancient marsh vegetation type, and open dry bog, thicket, and tamarack duplicate in many features Kiclianl Brewer BIRD POPULATIONS OF BOGS 389 forest-edge vegetation such as occurred along streams, cliff-edges, etc. throughout the history of the eastern deciduous forest. Thus, many species were probably already available to occupy these types. It seems entirely reasonable then that we may recognize four “clumps” of species corresponding to conditions of the ancient communities of marsh, deciduous forest, and deciduous forest edge and to the new spruce-fir forest community. It seems possible that a few species might find themselves pre-adapted for success in tamarack or cedar forest or in coniferous forest edge (largely provided by bogs) and might fairly rapidly become adjusted in their habitat selection and life history to these communities. The Nashville Warbler appears to come close to such a species for coniferous forest edge- tamarack, and the Olive-sided Flycatcher may represent another coniferous edge species. Possibly the Red-breasted Nuthatch is such a cedar forest species. I suspect that the hemlock-white pine-hardwood forests represent another community to which adaptation of several species has occurred and which has supplied species to mixed bog forests; however, the history of the former vegetation type is not clear (Braun, 1950:528). Both the organismic and individualistic concepts, in their usual practice, have failed to take adequate account of historical and evolutionary factors in community organization. The organismic concept seems to consider all communities as equally well integrated and, by implication, equally ancient. The individualistic concept seems to ignore history, except that of the individual stand, altogether. It is scarcely possible to deny the existence of biotic continua, in the sense that when the abundance of species is plotted against a real or hypothetical environmental gradient a series of curves with differing modes and amplitudes is produced. The existence of continua, however, seems to favor the orga- nismic concept. Given an area of deciduous forest for existence and adaptation, there seems every reason to believe that different species, as they experienced differential success resulting from competition, would become adapted to somewhat different conditions. I see little difference between this form of organization and such forms as stratification and aspection. In all three cases, the environment is divided up in a manner suggesting that the presence of other species has been important in the evolutionary processes producing such partitioning. The view that such organization depends solely on the combination at a particular time and place of species having tolerances and life histories that happen to fit one another and the physical environment is almost perfectly correct if all we are interested in is the instantaneous description of an individual stand; but it is incomplete. 390 THE WILSON BULLETIN Deccnihor 1967 Vol. 79, No. 4 Table 4 ZOOGEOGKAI’IIIC RELATIONS OF THE BkEEIHNG RiHDS OF VaHIOUS BoG VEGETATION Types ( Percent of Species in Each Faunal Group) Vegetation Unanalyzed Non-passerine Boreal Eastern ecotone Eastern deciduous forest Open 50 30 20 0 0 Thicket 26 13 35 22 4 Tamarack Forest 36 9 22.5 22.5 9 Spruce Forest 11 7 54 21 7 Cedar Forest 14 14 31 25 16 Mixed Forest 18 15 12 27 27 Zoogeographic relationships. — All species of at least 33 per cent fre- quency in each vegetation type (Table 3) were assigned to faunal groups (Udvardy, 1964). (Complete species lists for each vegetation type were not used because many species of low frequency may be represented for some nearly accidental reason, such as the presence of some favorable vegetation adjacent to a single study area.) This analysis supports the conclusions drawn in preceding sections. The early successional stages of open bog, thicket, and tamarack forest show high percentages of the wide- ranging species of the unanalyzed element (Table 4). Open bog, by virtue of its marsh birds, has a high percentage of non-passerine species. Spruce bogs are heavily dominated by boreal forest species; cedar forest has fewer boreal species and mixed forest still fewer. Eastern deciduous forest species show the reverse trend, increasing from boreal through cedar to mixed forest. To return to the question of bogs as boreal islands, we may examine the percentages of boreal species occurring on the individual study areas. Given in Figure 4, these show a strong latitudinal trend, northern bogs having high percentages and southern bogs low.“ At the latitude of northern Michigan it is reasonable to regard bog forests as boreal islands because both the actual and the presumed potential general vegetation of the region has a substantially lower percentage of boreal birds. For example, the beech- maple-pine forest in Cheboygan County (45.5° N. lat.) reported on by Kendeigh (1948 ) had only 12.5 per cent boreal species compared with values from 16 to 37 per cent for bog thickets and forests in the area. Farther north, however, the concept has less validity because the region in general is rather strongly boreal. For Aroostook County, Maine, Stewart and Aldrich 2 Some of Udvardy’s eastern ecotone species could be considered “boreal.” I have preferred to use Udvardy’s groups rather than risk the possible circularity involved in constructing my own. In any case, expansion of the boreal category to include group 1 of Udvardy’s eastern ecotone fauna would not change the trends described. 391 BIRD POPULATIONS OF BOGS Brewer Fig 4, Relationship between percentage of boreal species in the avifauna of 31 bog areas and latitude. Open symbols represent open bog, squares represent western areas (Minnesota and Manitoba), and diamonds, Appalachian areas (Maryland). (1952) state that a mixed hemlock-hardwood-spruce-fir forest is probably the climax vegetation. One such forest for which they give census data had 33 per cent boreal species compared with values from 24 to 58 for bog thickets and forests of the area. In Ontario, if hemlock forest is indeed climax (as Martin, 1959, states), the percentage of boreal species in the potential prevailing vegetation of the area is 50 per cent compared with 54 per cent for spruce and spruce-cedar bog forests (Martin, 1960). As one proceeds south from northern Michigan, the percentage of northern species declines. A comparison between Portage Bog and a tamarack bog in Ontario (Goodwin and Jarvis, 1964) illustrates this. The Ontario area has a much higher percentage of tamarack forest and much less open bog, but having allowed for these differences, the dissimilarity of avian populations is still striking. The two areas have 12 species (out of 40; 30 392 THE WILSON BULLETIN Dercmher 1967 Vol. 79, No. 4 per cent ) in common. Present on the Ontario area but absent from Portage Bog are such northern species as White-throated Sparrow, Canada Warbler, Red-breasted Nuthatch, Brown Creeper, Winter Wren, and Purple Finch. No similar array of species replaces these in the south, and as a result Portage Bog has a much less diverse avifauna ( mean number of species per year about 16 compared with about 20 for the Ontario area ) . The entire boreal element of the two southwestern Michigan areas consists of Tree Swallow, Black-capped Chickadee, and Traill’s Flycatcher. All three are widely distributed in non-bog vegetation in southwestern Michigan and farther south. More to the point as boreal, or at least northern species, are the Nashville Warbler at Portage Bog and the Black-throated Green Warbler at Sugarloaf Bog. Both are rare in southwestern Michigan, and the Nashville Warbler probably would not be present if bog vegetation were not present. Black-throated Green Warblers, however, have been reported as summer residents elsewhere in the region in non-bog forests ( e.g., MacArthur, 1964 ) . And finally, such good boreal species as the Brown Creeper (Walkinshaw, 1948) and the Winter Wren (Wallace, 1944) have spent the summer (and nested in the case of the creeper ) in two Michigan localities of about the same latitude as Kalamazoo County. Neither record was from a bog. In sum, the concept of bogs as boreal islands seems to have no validity when applied to bird populations of southwestern Michigan. A few other trends in the percentage of boreal species are also present. Open bogs are not particularly boreal in character whether located north or south. It must be remembered that open bogs have a high proportion of non-passerine and thus unclassified species; however, I do not think the conclusion would be substantially altered if the non-passerines were assigned to faunal groups. There appears also to be a trend toward increased numbers of boreal species in the Appalachians, as might be expected, and a decrease westward such that the Minnesota bogs and even those of Manitoba rate rather low in comparison with others of the same latitude. Succession. — Table 3 lists all species occurring in at least two open bogs, two bog thickets, and four bog forests ( i.e., all species having about a 25 per cent frequency or greater in one of the three types). Frequency and maximum reported density (mean number of males per 100 acres; only values over 10 included ) for each species in each of the six vegetational categories are given. This compilation is of descriptive value for two reasons. First, it is often handy to categorize bog vegetation into these six types and, within the already stated limitations of geographic and local variation, the lists indicate the prevailing avifauna of these vegetational categories. Second, the sequence open bog to mixed forest is a frequent successional pathway in northern Michigan (Gates, 1942 ). The table may be taken as a generalized Richard Brewer BIRD POPULATIONS OF BOGS 393 summary of bird succession in bogs if it is borne in mind that no real bog in northern Michigan or elsewhere is likely to exhibit just such a sequence of species. This is true because ( a ) succession of bird species in a given bog will have a strong local character because of differing geographical ranges of species, the influence of surrounding vegetation, and peculiarities of particular situations as they influence the structure of the vegetation, and (b) vegetational succession is itself highly variable both between and within regions. The sequence given is frequent in northern Michigan, but it often happens that spruce enters without an intervening tamarack stage. In south- western Michigan spruce and cedar are essentially absent and here the suc- cession may be from open bog to tamarack thicket to tamarack forest to mixed forest. Within a restricted geographical area, there appears to be a decrease in number of species from open wet bog to open dry bog and then an increase from open dry bog through thicket and forest. Probably these trends are related to a loss of marsh growth forms followed by the addition of low and then high woody strata. When numbers of species for given vegetation types are examined over larger geographical areas, however, these trends largely disappear; open dry bog is consistently low in species, but otherwise numbers overlap widely. This situation appears to result from the differing distributions of species able to make use of the various vegetation types. Specifically, it seems to be related to the decrease of boreal and eastern ecotone species southward and westward and the extent to which deciduous forest and forest-edge species enter the various vegetation types. Although densities as reported here for southwestern Michigan increased directly from open bog to thicket to mixed forest, this trend was not general. In Ontario, for example, open bogs had 50-100 more males per 100 acres than bog forests (Martin, 1060). Neither were there obvious geographical trends in population size. SUMMARY Bird populations were studied on two l)og areas in southwestern Mieliigan. One, a spliajinuni-Ieatherleaf-taniaraek hog, had an average of about 16 breeding species per year and an average density of al)out 170 males per 100 acres. Song Sparrow was by far th(‘ most abundant s{)ecies; Yellowtbroat, Rufous-sided Towbee, and Field Sparrow w(‘re also numerically important. All but the last showed higher densities in thicket eomi)ared with open {>arts of the hog. Most of the birds were forest-edge specie's of wide g<'ogra{)hical range. Populations were si)arse outside' the' hre'e'eling se'ason, probably he'e-ause' of a poor fe)oel supi)ly. dlu' se'e-e)nd are'a, a ye'llow hire h re'el maph'-while pine' h(»g fore-st, hael about 20 hre'e'el- ing spe'e-ie's a ye'ar. De'nsity was about 270 male's pe'r 100 ae re's. Blae k-e-appe'd ( diie kade'e'. Ove'iihirel, Wexxl Pe'we'e', P>lue' .fay, Carelinal, .Scarh't Tanage'r. anel four otlu'r spe'eies hael ele'usitie's gre'ate'r than 10 pe'r 100 aere's. Be'twe'e'ii 1%.S and 1066, the' numhe'r of Ovenhirels greatly ine-rease'el anel .Song .Sparre>ws gre'ally decline'd. 394 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Two ways of viewing hog bird communities are set forth. The first, classificatory or organismic, recognizes four main ecological groups of birds occurring in bogs (marsh, thicket or forest edge, spruce-fir forest, and deciduous forest), while acknowledging that any given stand may contain elements of more than one group. The second, individualistic, view emphasizes the tendency for each species to he distributed accord- ingly as it encounters suitable habitat within its range of geographic occurrence. The second view is essentially correct for the instantaneous description of a stand, hut it seems not to give sufficient weight to historical and evolutionary factors. The concept of hogs as boreal islands is valid for a certain range of latitudes. North of this, hogs are not much more boreal than surrounding vegetation and southward the number of boreal species rapidly diminishes until in southwestern Michigan there is practically no boreal character to the bird population. ACKNOWLEDGMENTS For assistance with various phases of field work, I am indebted to Frederick Courville, Willard Holley, and especially Jack W. Kammeraad and Arlo Raim. J. R. and B. Morren and C. S. Warren kindly allowed access to the study areas. LITERATURE CITED Aldrich, J. W. 1939 Red maple-yellow birch bog forest. Bird-lore, 41, Suppl.: 20-21. 1943 Biological survey of the hogs and swamps of northeastern Ohio. American Midi Nat., 30:346-402. Bailey, V. 1896 Tamarack swamps as boreal islands. [Reported by F. A. Lucas. Biological Society of Washington, 254th meeting, January 25] Science, n.s., 3:249-251. Batts, H. L., Jr. 1957 A preliminary report on seasonal distribution of birds in Kalamazoo County, Michigan. Jack-Pine Warbler, 35:9-13. Braun, E. L. 1950 Deciduous forests of eastern North America. Blakiston, Philadelphia. Breckenridge, W. j. 1955 Comparison of the breeding-bird populations of two neighboring but distinct forest habitats. Audubon Field Notes, 9:408-412. Brewer, R. 1963 Stability in bird populations. Occas. Papers Adams Ctr. Ecol. Studies, No. 7:1-12. 1966 Vegetation of two hogs in southwestern Michigan. Michigan Bot., 5:36-46. Brewer, R., and A. Raim 1966 Summer observations of Nashville and Black-throated Green Warblers in Kalamazoo County, Michigan. Jack-Pine Warbler, 43:169. Buckner, C. H., and W. J. Turnock 1964 Avian predation on the larch sawfly, Pristiphora erichsonii (Htg.), (Hyme- noptera: Tenthredinidae) . Ecology, 46:223-236. Curtis, J. T. 1959 The vegetation of Wisconsin. University of Wisconsin Press, Madison, Wis- consin. Daubenmire, R. 1966 Vegetation: identification of typal communities. Science, 151:291-298. Richard Brewer BIRD POPULATIONS OF BOGS 395 Duncan, D. P. 1954 A study of some of the factors affecting the natural regeneration of tamarack (Larix laricina) in Minnesota. Ecology, 35:498-521. Fairfield, G., J. Jarvis, and J. Woodford 1960 Tamarack Swamp. Audubon Field Notes, 14:494. Gates, F. C. 1942 The bogs of northern lower Michigan. Ecol. Monogr., 12:213-254. Goodall, D. W. 1963 The continuum and the individualistic association. Vegetatio, 11:298-316. Goodwin, C. E., and J. Jarvis 1964 Tamarack Swamp. Audubon Field Notes, 18:551-552. Jackson, H. H. T. 1914 The land vertebrates of Ridgeway Bog, Wisconsin: their ecological succession and source of ingression. Bull. W isconsin Nat. Hist. Soc., 12:4-54. Kendeigh, S. C. 1945 Community selection by birds on the Helderberg Plateau of New York. Auk, 62:418-436. 1948 Bird populations and biotic communities in northern lower Michigan. Ecology, 29:101-114. 1961 Animal ecology. Prentice-Hall, Englewood Cliffs, New Jersey. Kluyver, H. N., and L. Tinbergen 1953 Territory and the regulation of density in titmice. Arch. Neerland. ZooL, 10:265-289. Lefebvre, j. H. 1959 Preliminary ornithological survey of French Creek Bog. Flicker, 31:106-108. MacArthur, P. a. 1964 Upland beech mixed forest. Audubon Field Notes, 18:549. Martin, N. D. 1959 An analysis of forest succession in Algonquin Park, Ontario. Ecol. Monogr., 29:187-218. 1960 An analysis of bird populations in relation to forest succession in Algonquin Provincial Park, Ontario. Ecology, 41:126-140. Mengel, R. M. 1964 The probable history of species formation in some northern wood warblers (Parulidae). Living Bird, 3:9-43. Nice, M. M. 1941 The role of territory in bird life. American Midi. Nat., 26:441-487. 1943 Studies in the life history of the Song Sparrow. II. Trans. Linnaean Soc. New York, 6:1-328. Odum, E. P. 1945 The concept of the hiome as applied to the distribution of North American birds. Wilson Bull., 57:191-201. Prescott, K. W. 1965 Studies in the life history of the Scarlet Tanager, Piranga olivacea. New Jersey State Mus. Invest., No. 2. Robbins, C. S., and R. E. Stewart 1951 Scrub spruce bog. Audubon Field Notes, 5:325. Root, 0. M. 1942 The hog birds of Chel)oygan County, Michigan. Jack-Pine W'arbler, 20:39-44. 396 THE WILSON BULLETIN I)(M-onil)cr 1967 Vol. 79, No. 4 Smith, W. P. 1938 Balsani-hlack ash hog. Bird-lore, 40:354. 1941 Halsam-hlack ash hog and border. Audubon Mug., 43, Sect. 11:481-482. 1943 Balsam-hlack ash l)og and border. Audubon Mag., 45, Sect. 11:18. 1944 Balsam-hlack ash hog and border. Audubon Mag., 46, Sect. 11:15-16. 1945 Balsam-hlack ash hog and border. Audubon Mag., 47, Sect. 11:58-59. Stein, R. C. 1963 Isolating mechanisms between populations of Traill’s Flycatchers. Broc. Amer. Bhil. Soc., 107:21-50. Stewaht, R. E., and J. W. Aldrich 1952 Ecological studies of breeding bird populations in nf)rthern Maine. Ecology, 33:226-238. Stewart, R. E., and C. S. Robbins 1951 Virgin spruce-hemlock hog forest. Audubon Field Notes, 5:317-318. SVARDSON, G. 1949 Competition and habitat selection in birds. Oikos, 1:157-174. Tomfa, F. S. 1964 Factors determining the numbers of Song Sparrows, Melospiza melodia (Wilson) on Mandarte Island, B. C., Canada. Acta Zool. Fenn., 109:1-73. Transeau, E. N. 1903 On the geographical distribution and ecological relations of tbe bog plant societies of North America. Bot. Gaz., 36:401-420. Udvardy, M. D. F. 1963 Bird faunas of North America. Proc. Xlllth Internatl. Ornith. Congr., 1147- 1167. Walkinsiiaw, L. H. 1948 Brown creeper nesting in Calhoun County, Michigan. Jack-Pine Warbler, 26:157-160. 1949 Birds along the Tahquamenon. Jack-Pine Warbler, 27:91-98. Wallace, G. J. 1944 Winter wren at East Lansing in summer. Jack-Pine Warbler, 22:97-98. Williams, A. B. 1947 Climax beech-maple forest with some hemlock (fifteen-year summary). Audubon Field Notes, 1:205-210. C. C. ADAMS CENTER FOR ECOLOGICAL STUDIES, DEPARTMENT OF BIOLOGY, WESTERN MICHIGAN UNIVERSITY, KALAMAZOO, MICHIGAN, 3 AUGUST 1966. FALL MIGRATION OF SHARP-SHINNED HAWKS Helmut C. Mueller and Daniel D. Berger This paper is an analysis of data on the migration of Sharp-shinned Hawks {Accipiter striatus ) recorded at the Cedar Grove Ornithological Station in the autumns of 1952 through 1964. Particular emphasis is placed on: (1) the time of occurrence of the migrations, (2) the temporal distribu- tion of age classes during migration, (3) weather correlations, including a discussion of the structure of updrafts, and (4) the origins and destinations of the migrants observed at Cedar Grove. The station is located on the western shore of Lake Michigan about 40 miles north of Milwaukee, Wisconsin. A detailed description of the area can be found in Mueller and Berger (1966). A general description and analysis of hawk migrations at Cedar Grove is given in Mueller and Berger (1961). An essentially dawn-to-dusk watch for migrating hawks was main- tained on 915 days in the autumns of 1952 through 1964. Hawk traps were operated on most of these days, and on many days some of the observed migrants were trapped and banded. Observations often became sporadic on days with little or no migration; periodic watches were made with sufficient frequency to insure that few hawks passed unseen on any given observation day. Most of the hawks could be observed easily with the unaided eye, but 7 and 10 power binoculars and a 30 power spotting-scope were used when necessary, both for surveillance and as an aid in identification. In most years observations were conducted at the station on essentially every day from late August until at least late October. In 1952, 1956, and 1957 we sometimes left the station during periods of poor weather. A total of 17,628 Sharp-shinned Hawks was observed and 2,052 were trapped, banded, and released. The species has been recorded at Cedar Grove only as a migrant. Sharp-shinned Hawks occur only rarely in summer or winter in southern Wisconsin. Our earliest “autumnal” record of a Sharp- shinned Hawk at Cedar Grove is 13 August; the latest date on which we have observed this species is 6 December. Most of the hawks were seen in the period between 10 September and 20 October ( Fig. 1 ) . There are three peaks in occurrence within the period: two in mid- to late September and one in mid-October. However, the migrations of all species of hawks are highly correlated with weather conditions, and the temporal distribution of weather conditions must be taken into account in any attempt to determine the periodicity of migration. At Cedar Grove major fall hawk flights usually occur when the weather map has the following characteristics: (1) a low pressure area to the north- 397 398 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 east and high pressure to the southwest of Cedar Grove; (2) the isobars lie across Wisconsin on a northwest-southeast diagonal, and (3j a cold front lies somewhere to the south and east ( Class A weather of Mueller and Berger, 1961). However, Class A weather can occur without a concurrence of a major flight of Sharp-shinned Hawks (Fig. 1). Within the period 10 September through 20 October there is only one marked peak in the weather histogram; this coincides with one of the peaks in the hawk histogram. The remaining two peaks in the occurrence of Sharp-shinned Hawks, as well as the low point in occurrence in early October do not coincide with the peaks and low points in the distribution of Class A weather (Fig. Ij. The occur- rence of major flights, those days on which more than 100 Sharp-shinned Hawks were seen, closely resembles the distribution of the average number of hawks observed; and, similarly, seems to show two peaks which occur semi-independent of the distribution of weather (Fig. 1). The age ratio of birds that were trapped indicates that immature birds predominate early in the season and that adults predominate late in the season. After 30 October very few Sharp-shinned Hawks are seen or trapped; many of these very late birds are immatures. Thus, there appear to be two peaks in the fall migration of Sharp-shinned Hawks at Cedar Grove: one in mid-September, composed mostly of immature birds, and one in mid-October, composed largely of adults. WEATHER CORRELATIONS The four most important meteorological factors associated with the fall migration of Sharp-shinned Hawks at Cedar Grove are probably (1) wind direction and velocity, (2) cold fronts, (3) the decrease in temperature concomitant with frontal passage, and (4) sunshine. The correlations of weather with migration presented in Figures 2, 3, and 4 are based on data from 29 August through 28 October of the years 1958 through 1963, inclusive, a total of 352 observation days. Fig. 1. Temporal distribution of Sharp-shinned Hawks, suitable migration weather, major hawk flights, and age ratio; for the years 1952 through 1964. The abscissa indicates calendar date; the data are grouped in five-day intervals and each bar thus represents five calendar days and from 21 to 64 observation days. Hawks: the mean number of Sharp-shinned Hawks observed per day. Weather: the total number of days having Class A weather (see text). Flights: the total number of days on which more than 100 Sharp-shinned Hawks were observed. The lower histogram indicates the age ratio of the birds that were trapped. SHARP-SHINNED HAWK MIGRATION 399 400 IHE WILSON BULLETIN December 1967 Vol. 79, No. 4 Fig. 2. Sharp-shinned Hawk migration in relation to time The bars indicate the mean number of Sharp-shinned Hawks and line the number of observation days on which each bar of passage seen per is based. of cold day, the fronts. points Cold fronts. — The time of passage of cold fronts at Cedar Grove was estimated by examination of the U. S. Weather Bureau publications, Daily W eather Map, Local Climatological Data, and Local Climatological Data Supplement for Milwaukee, Wisconsin, and from uninstrumented observa- tion at Cedar Grove. The mean time interval between cold fronts was 3.8 days and the maximum interval was 9 days during the six autumn study- periods. More than 39 per cent of all the Sharp-shinned Hawks observed migrated over Cedar Grove within one day after the passage of a cold front, and a total of 72 per cent passed within two days of frontal passage. The mean number of Sharp-shinned Hawks observed per day dropped sharply on the third and fourth days after the passage of a cold front and then increased slightly five or more days after the frontal passage (Eig. 2). This increase in hawks observed when the interval between cold fronts is prolonged is apparently the result of birds crossing a slowly moving or stationary front and therefore occurring before an oncoming front rather than after the preceding one. Thus, most hawks migrate in the relatively cooler air behind Mueller and Berger SHARP-SHINNED HAWK MIGRATION 401 Fig. 3. Correlation of Sharp-shinned Hawk migration with wind direction and velocity. The wind data are the vector means of the 12 hourly readings taken between 0600 and 1700 hours at the U. S. Weather Bureau Station in Milwaukee, Wisconsin. The radial lines enclose 22.5° increments of mean wind vector-directions (e.g. all mean winds between W and WNW ) . The concentric circles enclose five mph increments of the vector-mean velocity. The intensity of shading within a given segment of the graph indicates the mean number of Sharp-shinned Hawks seen per day under the indicated conditions of wind direction and velocity. For example, a mean of more than 100 Sharp- shinned Hawks per day was observed on those days having a mean wind vector lying- bet ween W and WSW in direction and 20 to 25 mph in velocity. a cold front, and a few cross slowly moving or stationary fronts into the relatively warmer air preceding the front. Wind. — More than 93 per cent of the Sharp-shinned Hawks observed at Cedar Grove occurred on days when the mean diurnal wind was westerly. 402 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 The greatest mean number of hawks per clay was seen when the mean diurnal wind was cjuite strong and had a marked westerly component ( Fig. 3). esterly winds drift southbound hawks eastward until they encounter the west shore of Lake Michigan (Mueller and Berger. 1961). Hawks are reluctant to fly out over the lake, and they tend to follow the leading line formed by the shore of the lake. A concentrated stream of migrating hawks results from the interaction of wind drift and the leading line. A detailed discussion of these phenomena can be found in Mueller and Berger ( 1967 I . Few hawks were seen on days when easterly winds prevailed. Easterly winds apparently drift birds away from the lakeshore (Mueller and Berger, 1961). The wind usually has a northerly component after the passage of a cold front, although occasionally the winds are SW, or more rarely SW, after frontal passage. Thus, the occurrence of some massed migrations on S\^ winds is not surprising. However, the occurrence of migrating hawks on SSW, S, and even SE winds as compared with the paucity of migrating hawks on N and NNA\^ winds is interesting (Fig. 3 ) . The action of wind drift in NNW winds may be considerably less than in SS\^ winds. Northerly winds speed the southward passage of the birds allowing less time for drift while southerly winds slow the southward progress permitting wind drift to affect the bird for a longer period. Birds fly higher in a tail wind and exhibit less of a tendency to follow leading lines than in a head wind, when they fly lower ( Mueller and Berger, 1967 ) . hen the wind is southerly at Cedar Grove there is a local tendency for the wind to blow in off of Lake Michigan, giving the wind in the immediate vicinity of the lake an easterly vector. In the warmer air mass usually associated with southerly winds, the air over the lake is often cooler than that over the land. hen this cooler air blows in over the warmer land, displacing the warmer air, a line of updrafts paralleling the lake may be created, and. as we will show later, hawks apparently utilize updrafts. Once a hawk has found these updrafts, it might be induced to stay in the updraft zone, and thus fly along the lake- shore. In the cooler air mass usually associated with northerly winds there is little difference in temperature between the air over the lake and that over the land. Under these conditions we would expect about as many updrafts at any inland locality as we would along the lakeshore and, hence, no con- centrations of hawks. Temperature change. — In view of the correlation of the migration of Sharp-shinned Hawks and the recent passage of cold fronts, it is not surpris- ing to find that the migrations correlate rather well with a recent drop in temperature (Fig. 4). In an earlier paper on the influence of weather on the migrations of all species of hawks (Mueller and Berger, 1961), we Mueller and Berger SHARP-SHINNED HAWK MIGRATION 403 Fig. 4. Temperature change and the migration of Sharp-shinned Hawks. The bars indicate the mean number of hawks observed and the points and line the number of observation days on which each bar is based. attempted to correlate migration with a variety of temperature measurements and changes in temperature. Of these attempts, perhaps the best correlation was obtained by use of the departure of the mean 0030 ( CST ) temperatures for Duluth, Minnesota, Wausau, Wisconsin, and Escanaba, Michigan, from the corresponding data of the previous day. This measurement repre- sents an index of temperature change in the probable area of immediate origin of the migrations observed at Cedar Grove. This temperature change was used in compiling Figure 4 and is the only datum used in temperature analvsis in this paper. More than 69 per cent of the Sharp-shinned Hawks observed at Cedar Grove occurred when the area temperature had dropped during 404 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 PERCENT SUNSHINE Fig. 5. The migration of Sharp-shinned Hawks in relation to sunshine. The incidence of sunshine is expressed in terms of the per cent of the possible sunshine. The bars indicate the mean number of hawks observed and the points and line indicate the number of observation days on which each bar is based. the previous 24 hours. The greatest number of hawks per day was observed when there was a marked decrease in temperature, although many hawks were seen when the temperature dropped only slightly (Fig. 4). The slight increase in the number of birds observed when there was a marked increase in temperature may be attributed, largely, to those birds that crossed slow moving or stationary cold fronts into the warmer air mass preceding the front. Sunshine. — More than 84 per cent of the Sharp-shinned Hawks observed at Cedar Grove occurred on days when the sun was shining at least half of the time between sunrise and sunset (Fig. 5). Insolation heats the ground, and the warmed ground heats the air immediately above. Warm air rises, creating updrafts. The cooler air and the usually partly cloudy or clear skies in the air mass following a cold front provide optimal conditions for updraft formation. UPDRAFTS In the lower layers of the atmosphere updrafts can largely be placed into two classes: (1) mechanical updrafts caused by the vertical deflection of the Mueller ami Herger SHARP-SHINNED HAWK MIGRATION 405 horizontal wind, as on a mountain ridge, and (2j thermal updrafts, the rising of warmer, less dense air through cooler, denser air. The structure of thermal updrafts varies with the temperature difference between the air and the underlying surface, the roughness of the surface, and the wind velocity. The temperature responses to insolation of ground surfaces and their heat capacities also vary widely. Little is known about the structure of updrafts under these varying conditions. Earlier theories held that thermal updrafts were in a columnar form. Later theories held that convection over a terrestrial surface was in the form of discrete bubbles (Ludlam and Scorer, 1953 ). More recently. Cone (1962) theorized, partly on the basis of observations of soaring birds, that updrafts over a terrestrial surface take the form of discrete vortex rings. In addition to the upward movement of such a vortex ring, the air on the surface of the ring circulates in such a way that it moves upward on the inside of the ring and downward on the outside. Birds remain airborne by soaring in circles in the upeurrents on the inside of the ring. Cone (1962:190) observed that individuals of a group of soaring birds always circle at about the same altitude, and he offers this as partial evidence in proof of his vortex ring hypothesis. However, on many occasions we have observed Broad-winged Hawks [Buteo platypterus) soaring in circles in a column, with birds more or less uniformly distributed at all altitudes in the column. On a few occasions the height of the column of circling birds, from the lowest birds to the highest, exceeded 1,000 feet. The updrafts must have been in the form of a column, or in the form of a continuous chain of bubbles or vortex rings. Further systematic observations of circle soaring in various localities and under a variety of conditions are needed. Our observations also suggest that still other forms of updrafts may exist. The great majority of Sharp-shinned Hawks that migrate over Cedar Grove do not soar in circles. The typical mode of flight consists of a few flaps of the wings followed by an extended glide, all in an approximately straight line. The birds appear to be utilizing updrafts since they often rise 25 to 50 feet with little or no flapping of wings. On windy days even the larger hawks and vultures, which normally soar in circles, are seen to pass over Cedar Grove in a more or less straight line. Many of these birds fly for hundreds of feet without flapping and without losing altitude. Hankin (1913) lists many similar observations of rectilinear soaring or gliding by Indian birds of prey. Woodcock (1942) studied updraft structure over the North Atlantic Ocean by watching the soaring of gulls. Gulls soared in circles when the surface water temperature was at least 2 degrees C higher than that of the overlying air and the wind velocity was less than 15 mph. When the air-water tempera- 406 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 ture difference was at least 4 degrees C and the wind velocity was between 15 and 28 mph the gulls soared in straight lines, headed upwind. No soaring was observed at wind velocities greater than 28 mph, presumably because updraft structure was disrupted or updrafts were of insufficient lateral extent to support gulls. He hypothesized that under these conditions of moderate to high winds the thermal updrafts were in the form of longitudinal, vertical sheets, oriented up- and downwind. These updraft sheets are probably the rising portions of horizontally oriented helical vortices, convection cells in which the long axis is parallel to both the wind and the surface of the earth. Similar convection cells have been observed in a lake ( Langmuir, 1938 ) and in the laboratory (Phillips and Walker, 1932; Graham, 1934). An ocean surface is flat and is uniform in temperature. Land surfaces are irregular, and the surface temperature often varies greatly over a distance of a few feet. Convection patterns over a land surface undoubtedly differ from those over the ocean. However, the presence of a strong horizontal wind certainly must affect the structure of updrafts over a land surface. In the absence of evidence to the contrary, we suggested in an earlier paper ( Mueller and Berger, 1961 ) that updrafts over a land surface, under con- ditions of high land-air temperature contrast and winds of 15 to 30 mph, might assume a form similar to that described by Woodcock (1942). 4 he irregularities in topography and temperature of the ground, acting indi- vidually or in combination, might produce a quasi-permanent distribution of updrafts over a land surface in the presence of moderate to high winds. Mechanical updrafts would remain in the same place as long as the wind remained constant in direction and velocity. Areas with high surface temperatures would remain largely unchanged as long as the amount of heat delivered to the surface remained unchanged. Thus, for periods up to a few hours the updraft distribution over a given area might vary only slightly. We have often noted that most of the hawks observed at Cedar Grove in a given period of time appear to be following one or several invisible, three- dimensional paths through the air over the area. Many of the hawks change direction and altitude at the same points where previous hawks have altered course and altitude. Since the hawks do considerable gliding, this suggests that they are “following” an updraft pattern through the area. We do not know to what extent Sharp-shinned Hawks use such updrafts away from a leading line, but once they arrive at the western shore of Lake Michigan in the vicinity of Cedar Grove the hawks definitely appear to be using an updraft pattern that permits rectilinear gliding at low altitudes. Since most of the Sharp-shinned Hawks observed at Cedar Grove occur on days favor- able for the formation of updrafts (Figs. 3, 4, and 5) and when moderate Mueller and Berger SHARP-SHINNED HAWK MIGRATION 407 to strong winds are blowing (Fig. 2) it may be that most Sharp-shinned Hawks migrate when the updraft pattern is somewhat similar to that described by Woodcock (1942). However, Sharp-shinned Hawks occur at Cedar Grove on westerly winds, and increased wind velocities increase the effects of wind drift. With increased drift, increasing numbers of birds arrive at the leading line formed by the shore of Lake Michigan, and larger numbers of hawks are counted at Cedar Grove. Thus, most Sharp-shinned Hawks may migrate on days on which updrafts and strong winds occur, or the correlation of migration with strong winds at Cedar Grove may be purely the result of increased wind drift. We suspect that Sharp-shinned Hawks exhibit a greater tendency to migrate on windy days. Regardless of the structure of updrafts, our data indicate that most Sharp-shinned Hawks migrate on days when the weather conditions are conducive for the formation of updrafts. The cooler air, and the partly cloudy skies in the air mass following a cold front provide optimal conditions for the formation of updrafts. EXTRAORDINARY MIGRATIONS AND WEATHER In the autumns of 1952 through 1964 we have recorded 42 days on which more than 100 Sharp-shinned Hawks were observed at Cedar Grove. More than 400 Sharp-shinned Hawks were seen on only four days: 486 were observed on one day, 676 on another, and on each of two days extraordinary totals of more than 1,200 Sharp-shinned Hawks were seen. The latter two days, 15 September 1952 and 13 October 1955, were associated with a sequence of weather conditions that occurred only during the brief periods prior to and including these two days and not again during the 13 years of our study. The essential feature of the weather map at these times was a cold front extending from east to west, which penetrated into northern Wisconsin, stalled, and then retreated slowly to Lake Superior over a period of two or three days (Fig. 6). A second cold front, extending from north to south swept through the area three to five days after the first front and continued onward to the east and south (Fig. 6j. The extraordinary flight in both cases occurred on the day after the second front passed Cedar Grove. In both of these cases of extraordinary flights, we believe that it is probable that the Sharp-shinned Hawks began to migrate with the southward move- ment of the first cold front. When this front stalled, and subsequently re- treated, a few hawks probably continued to migrate southward, but we suspect that most individuals soon ceased migrating. The weather situation thus deposited great numbers of hawks in northern Wisconsin and upper Michigan. The second cold front again initiated migration, and unusual numbers of hawks passed Cedar Grove. 408 THE WILSON BULLETIN Deceinl)er 1967 Vol. 79, No. 4 Table 1 Wind Direction and Velocity at 1200 iirs. Date Hawks* • U. S. Weather Bureau Station* Dlh LCr SSM GrB Mke 12 Sept. 1952 31 S 10 SSW 8 E 6 SSW 11 ESE 15 13 87 ESE 12 S 12 SE 5 SSW 16 SE 13 14 285 WSW 25 NW 17 SSE 14 SW 16 SW 20 15 1219 WNW 20 WNW 20 NW 6 WNW 23 W 21 10 Oct. 1955 43 SSE 8 SSE 10 WSW 9 SW 20 SW 15 11 16 SSE 21 S 20 S 7 SW 17 SW 18 12 200 WNW 35 NW 22 ESE 12 WNW 22 WNW 23 13 1220 NW 23 NW 20 SSW 7 NW 22 WNW 21 * Duluth, LaCrosse, Sault Ste. Marie, Green Bay, and Milwaukee. ** Number of Sharp-shinned Hawks observed at Cedar Grove. Table 1 presents the noon records of wind direction and velocity recorded by the U. S. Weather Bureau at Milwaukee and four selected points to the north and northwest during the two critical periods which ended with the extraordinary flights. On 12, 13, and 14 September 1952 the winds at noon at Sault Ste. Marie, Michigan, had an easterly component ( Table 1 ) . Birds flying over the isthmus between Lakes Superior and Huron would presum- ably be drifted westward and would have an increased probability of ending up on the western, rather than the eastern side of Lake Michigan. Those hawks that continued southward into Wisconsin encountered winds with a westerly component in the vicinity of Green Bay, Wisconsin, and presumably were drifted eastward to Lake Michigan. A few birds presumably continued to follow the leading line provided by the lakeshore on 12 and 13 September, even though the winds again became easterly in the vicinity of Milwaukee (Table 1). On 14 September the winds were westerly at both Green Bay and Milwaukee, and the daily count of Sharp-shinned Hawks increased accordingly. Noon wind recordings at Duluth, Minnesota, at the western end of Lake Superior, suggest that the winds in this area were not adequate to drift birds toward Gedar Grove until 14 September, when strong WSW winds may have provided for sufficient eastward drift ( Table 1 ) . At LaCrosse, approximately south of Duluth and west of Cedar Grove, winds had either a positive or neutral westerly component throughout the period (Table 1). The weather data thus suggest that hawks were trickling south- ward from the Sault Ste. Marie area toward Cedar Grove from 12 through 14 September 1952. The strong WSW winds at Duluth may have begun to add to this flow on 14 September. On 15 September strong westerly to Mueller and 15ert;er SHARP-SHINNED HAWK MIGRATION 409 Fig. 6. Positions of fronts in the eastern United States at 1200 hours (csx) on each of several days. Left: 9 through 15 September 1952. Right: 9 through 13 October 1955. 410 THE WILSON BULLETIN December 1967 Vol. 79, No. 1 northwesterly winds and optimal conditions for migration quickened the flow, resulting in a record count of Sharp-shinned Hawks at Cedar Grove. The extraordinary flight of Sharp-shinned Hawks on 13 October 1955 was preceded by only slightly different wind conditions than that of Septem- ber 1952. Winds with an easterly component at Sault Ste. Marie did not prevail until 12 October. As a result, hawks entering the Wisconsin area at Sault Ste. Marie may have contributed less to the flight of 13 October 1955 than that of 15 September 1952. The noon wind at Duluth on 12 October 1955 had an extremely high westerly component of more than 32 mph, and it is possible that birds entering Wisconsin in the Duluth area contributed greatly to the record flight observed at Cedar Grove on 13 October 1955. Winds were westerly at Milwaukee and Cedar Grove through- out the four-day period, providing good local conditions for the drift of birds to the shore of Lake Michigan (Table 1). On 12 and 13 October 1955 the westerly component of the wind was particularly high at Milwaukee, and other weather conditions were also optimal for migration. Thus, the spectacular flights of Sharp-shinned Hawks on 15 September 1952 and 13 October 1955 appear to be due to an unusual sequence and movement of fronts and to the temporal and spatial distribution of wind conditions in the area north of Cedar Grove. RECOVERIES OF BANDED BIRDS We know of 57 recoveries of Sharp-shinned Hawks banded in the vicinity of Cedar Grove (Lig. 7). Eighteen birds were recovered before 15 December of the same autumn in which they had been banded (closed circles in Eig. 7). The mean angle from Cedar Grove for this distribution of recoveries is about 10 degrees east of south. Fifteen birds were recovered during the winter (15 December through 15 March ) immediately following the autumn in which they were banded (closed triangles of Fig. 7). The distribution of these recoveries has an average angle of about five degrees east of a line drawn south from Cedar Grove, an angle not significantly different from that of the autumn recoveries. Both the autumn and winter recoveries show a marked change in mean direction with change in latitude. The 17 birds recovered north of the southern border of Tennessee and within five months of the time of banding have a geographic distribution which yields a mean angle of 18 degrees east of a line drawn south from Cedar Grove. The distribution of the 16 similar recoveries from south of the Tennessee border yields a mean angle of 7 degrees west of south, about 25 degrees farther west than the more northern recoveries. The prevailing winds during September, October, and November generally have a westerly component in the north central United Mueller and Berger SHARP-SHINNED HAWK MIGRATION 411 Fig. 7. Distribution of recoveries of Sharp-shinned Hawks banded at Cedar Grove during autumnal migration. Closed symbols indicate birds recovered less than one year after the time of banding; open symbols indicate birds recovered four seasons or more after the time of banding. Circles: autumn recoveries (1 September-15 December). Triangles: winter recoveries (16 December-15 March). Squares: spring recoveries (16 March-31 May). Other symbols indicate localities mentioned in the text. States and an easterly component in the states bordering the Gulf of Mexico (U. S. Department of Commerce, 1964). The apparent tendency for hawks to move south-southeastward from Cedar Grove and then turn somewhat to the west in the southern United States may thus be nothing more than a result of wind drift. The above evidence suggests that the heading, or standard direction, of migration of the Sharp-shinned Hawks observed in autumn at Cedar Grove is approximately due south. The eight birds that were recovered in winter a year or more subsequent to the time of banding add little to the above discussion except: (1) there is one far northern recovery, in the vicinity of Cedar Grove, and ( 2 ) there is one far southern recovery in southeastern Guatemala (open triangles of Fig. 7). 412 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Six of the eight birds recovered in autumn one or more years after the autumn in which they had been banded are of considerable interest ( open circles of Fig. 7). Four of these birds were recovered to the north of Cedar Grove, one at the western end of Lake Superior, two at the eastern end, and one just west of Green Bay. The distribution of these four recoveries suggests that Sharp-shinned Hawks observed at Cedar Grove during autumnal migration enter the Wisconsin area around both ends of Lake Superior, with possibly the majority entering through the Sault Ste. Marie region. Two birds were retrapped at the Cedar Grove Ornithological Station ap- proximately one year after banding, indicating that individual birds occasion- ally occur at the same point on the migratory route in subsequent years. However, the recurrence at Cedar Grove of these two individuals can probably be attributed to a chance distribution of weather patterns which brought the birds to the same point on the migratory route in two consecutive years. We trap about 12 per cent of the Sharp-shinned Hawks we observe at Cedar Grove. If we assume a 50 per cent annual mortality for the combined sample of juveniles and adults, and that all survivors of the group of birds banded at Cedar Grove will recur there during the next autumn, we would expect to catch six birds for every 100 banded the previous autumn. We would expect to have recaptured 104 banded Sharp-shinned Hawks at Cedar Grove in the autumn subsequent to the year of banding. We would further expect additional birds to be recaptured two or more years after banding. The fact that only two birds have been recaptured suggests that individual Sharp-shinned Hawks do not follow the same migratory route year after year. Two of the seven hawks recovered during the time of spring migration (15 March through 31 May) are of interest (squares in Fig. 7). These two individuals were recovered to the east of Lake Michigan, suggesting that migratory routes change with the season or that Sharp-shinned Hawks do not follow the same migratory route year after year. We have obtained only one summer recovery of a Sharp-shinned Hawk. This bird, banded as an adult on 17 October 1964, was found dead on 22 July 1965 at Fawcett, Alberta, about 1,500 miles northwest of Cedar Grove. OTHER OBSERVATIONS OF HAWK MIGRATION IN THE UPPER GREAT LAKES AREA Many of the hawks observed at Cedar Grove probably enter Wisconsin and upper Michigan by passing around the ends of Lake Superior. The spectacular flights at Duluth, at the western end of Lake Superior, are well known (Hofslund, 1954). ( See point A in Figure 7. The parenthetical letters after other locations mentioned below also refer to Figure 7). Great Mueller ami Berger SHARP-SHINNED HAWK MIGRATION 413 numbers of hawks apparently also enter the Lnited States at the eastern end of Lake Superior, but the flights are less well known because often the birds are not found in as concentrated a “flyway” as at Duluth. Some hawks cross Whitefish Bay to Whitefish Point ( B ) some 40 miles west of Sault Ste. Marie (C. Hawkins, pers. comm.). J. M. Speirs (pers. comm.) has observed a broad-front movement through the Sault Ste. Marie area ( C ). Concentrated hawk flights have also been observed on the north shore of Lake Huron (D ) between Detour and the Pine River (K. Slater, pers. comm.). Some hawks may cross Lake Superior. Concentrations of hawks occur in fall at Isle Royale (E) (Peet, 1909). Lesser concentrations occur on the Apostle Islands (L) (J. Keener, pers. comm.) and on the Keweenaw Peninsula ( G ) ( Binford, 1965 ) . The concentrations at the latter two points may be the result of the northbound wanderings of young hawks rather than overwater migrations. In spring hawks do depart in a northerly direc- tion across Lake Superior from the tip of the Keweenaw Peninsula ( Wood, 1933 ) . On the south shore of Lake Superior, the Bayfield County peninsula, the Keweenaw Peninsula, and Whitefish Point all provide leading lines which tend to gather and direct hawks out over the lake. On the other hand, the leading lines of the north shore (except for the islands and peninsulas in the limited area north of Isle Royale ) tend to lead birds to the ends of the lake. We suspect that the majority of the hawks involved migrate around, rather than across. Lake Superior in autumn. We know little of what happens to the Duluth hawk flights after they pass south of Lake Superior. S. Robbins ( pers. comm. ) occasionally has seen hawk movements near Roberts, Wisconsin (H). The Sault Ste. Marie flights are somewhat easier to trace. Hawk movements have been observed both inland (I) and on the north shore of Lake Michigan (J) in Schoolcraft County, Michigan (K. Christofferson, pers. comm.; Beebe, 1933). C. Richter (pers. comm.) has observed hawk flights on the west shore of Green Bay (K) which in some instances correlated rather well with flights seen a day or so later at Cedar Grove. H. Wilson (pers. comm.) once saw migrating hawks at the northern tip of the Door County Peninsula ( L ) . suggesting that some hawks may cross the mouth of Green Bay on the chain of islands stretching from Delta County, Michigan, to Door County, is- consin. Some 20 miles south of Cedar Grove the volume of hawk migration appears to be reduced. Hawk flights are rarely observed in or about the city of Milwaukee, about 40 miles south of Cedar Grove. Near Racine, an- other 20 miles south, some hawk migration is again observed (M. Higgins, pers. comm.). Some migrating hawks are also seen near Zion, Illinois (J. 414 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 \^'eaver. pers. comm. ) , but south of this point we have no information concerning hawk flights. The number of hai\ks ohser\ecl at the last t\so localities is usually not as great as at Cedar Grove. To summarize these observations, hawk flights have been observed at both the east and west ends of Lake Superior. Some hawks may cross Lake Superior. Hawk flights have been observed at a number of points on the west shore of Lake Michigan. The volume of the flight varies as does the direction of the lakeshore, the topography, the incidence of urban and industrial areas, and the distribution of habitat types. Lack of repoits from the areas between known hawk migration points does not imply that flights are lacking; too often it means that adequate observations have not been made. Many of the Sharp-shinned Hawks observed at Cedar Grove probably enter the United States at Sault Ste. Marie. Most of the rest of the hawks seen at Cedar Grove probably enter Wisconsin near Duluth. SUMMARY Daily counts of Sharp-shinned Haivks were conducted on 915 days in the autumns of 1952 through 1964. A total of 17,628 Sharp-shinned Hawks was observed and 2,052 were trapped, banded and released. There are two peaks in the autumnal migration, one in mid-September, composed mostly of immature birds, and one in mid-October, composed largely of adults. Ninety-three per cent of the Sharp-shinned Hawks were observed on days with westerly winds, 72 per cent were recorded within two days of the passage of a cold front, 69 per cent were seen on days when the area temperature had dropped during the previous 24 hours, and 84 per cent were observed on days when the sun was shining for at least one-half of the time between sunrise and sunset. On the basis of these data we suggest that hawks fly when conditions are conducive for the formation of updrafts and that wind drift concentrates migrants along the leading line formed by the western shore of Lake Michigan. The flight behavior of hawks and the structure of updrafts is discussed in some detail. An analysis of two extraordinary migration flights suggests that weather conditions hundreds of miles to the north may affect the numbers of birds seen at Cedar Grove. The recoveries of banded birds, and observations of hawks at other points in the Lpper Great Lakes region suggests that most of the hawks seen at Cedar Grove enter the area at the eastern and western ends of Lake Superior. The distribution of fall and winter recoveries suggest that the birds head approximately southward, are drifted eastward in the north and central portions of the eastern United States, and are drifted westward in the states bordering the Gulf of Mexico. ACKNOWLEDGMENTS Frances Hamerstrom. K. H. Kuhn, H. E. Meinel, N. S. Mueller, J. J. Oar, D. E. Seal, C. R. Sindelar, and others aided in the field work. The study was supported in part by the National Science Foundation (Grant GB-175). The Cedar Grove Ornithological Station is a cooperative project of the University of Wisconsin and the isconsin Conservation Department. We are indebted to J. T. Emlen for frequent aid, counsel, and encouragement. Mueller and Berger SHARP-SHINNED HAWK MIGRATION 415 LITERATURE CITED Beebe, R. 1933 Influence of the Great Lakes on the migration of birds. Wilson Bull., 45: 118-121. Binford, L. C. 1965 Unusual bird records from the upper peninsula of Michigan. Jack-Pine Warbler, 43:144-145. Cone, C. D. 1962 Thermal soaring of birds. Amer. Scientist, 50:180-209. Graham, A. 1934 Shear patterns in an unstable layer of air. Phil. Trans. Royal Soc. London, 232A: 285-296. Hankin, E. H. 1913 Animal flight; a record of observations. Iliffe, London. Hofslund, P. B. 1954 The hawk pass at Duluth. Flicker, 26:97-98. Langmuir, I. 1938 Surface motion of water induced by wind. Science, 87:119-123. Ludlam, F. H., and R. S. Scorer 1953 Convection in the atmosphere. Quart. Jour. Royal Meteorol. Soc., 79:317-341. Mueller, H. C., and D. D. Berger 1961 Weather and the fall migration of hawks at Cedar Grove, Wisconsin. Wilson Bull., 73:171-192. 1966 Analyses of weight and fat variations in transient Swainson’s Thrushes. Bird-Banding, 37:83-112. 1967 Wind drift, leading lines, and diurnal migration. Wilson Bull., 79:50-63. Peet, M. M. 1909 The fall migration of birds at Washington Harbor, Isle Royale, in 1905. Michigan Geol. Surv. Ann. Rept. for 1908: 97-119. Phillips, A. C., and G. T. Walker 1932 The forms of stratified clouds. Quart. Jour. Royal Meteorol. Soc., 58:29-30. U. S. Department of Commerce, Weather Bureau 1964 Prevailing direction, mean speed (m.p.h.), and fastest mile of wind. Sheet of the National Atlas of the United States. U. S. Government Printing Office, Washington, D. C. Wood, N. A. 1933 Birds of Keweenaw Point, Michigan. Papers Michigan Acad. Sci., Arts, Letters, 17:713-733. Woodcock, A. H. 1942 Soaring over the open sea. Sci. Mon., 55:226-232. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF WISCONSIN, MADISON, WISCONSIN, AND CEDAR GROVE ORNITHOLOGICAL STATION, ROUTE 1, CEDAR GROVE, WISCONSIN. (present address: (hcm) department of zoology, university of north CAROLINA, CHAPEL HILL, NORTH CAROLINA), 31 MAY 1966. SELECTION FOR A DELAYED SIMULTANEOUS WING MOLT IN LOONS (GAVUDAE) simultaneous molt of the remiges, with its concomitant flightless period, is a feature widespread in the class Aves. It has been re- corded for members of no less than ten orders of flying birds: Gaviiformes (Palmer, 1962), Podicipediformes (Palmer, op. cit.), Procellariiformes (Murphy, 1936), Pelecaniformes (Palmer, op. cit.), Phoenicopteriformes (Palmer, op. cit.), Anseriformes ( Delacour, 1954), Gruiformes (Van Tyne and Berger, 1959; Witherby et al., 1940), Charadriiformes ( Storer, 1960), Coraciiformes (Van Tyne and Berger, op. cit.), and Passeriformes (Sullivan, 1965). Knowledge of the considerable expenditure of energy required for the replacement of feathers has led to the conclusion that molt is normally a prolonged process and that rapid feather replacement develops only as a result of strong environmental selection (Humphrey and Parkes, 1959). For the remiges the consensus seems to be that simultaneous molt occurs only when it is the sole means by which a species can survive. This is perhaps true for loons as is discussed below, but two reasons suggest it may not be the case for all such birds, namely seasonal fluctuations in the abundance of food, and the extra energy required for flight by birds undergoing a gradual wing molt. It is possible that some of the wide variety of species with a simultaneous wing molt occupy niches in which either method could occur, hut that rapid replacement confers slight advantages and therefore has been A simultaneous loss of the remiges is probably a necessity for loons. D. B. 0. Savile ( 1957 ) states, “The Common Loon ( Gavia irnnier) is a flying anachronism. ... It has an appallingly high wing loading and a very inefficient wing form. Under these handicaps it takes off only with difficulty, after a long run, and climbs shallowly.” It seems likely in a species so poorly designed for flight that the loss of even one remex from each wing would be a considerable handicap. Typically the simultaneous loss and replacement of flight feathers is a post-breeding, late summer or early fall phenomenon — a phase of the prebasic molt. Hornbills, the coraciiform example, are exceptions, for females of certain species are flightless during breeding. The habit of the male sealing the female in the nest cavity provides the ecological opportunity. The three large species of loons are also exceptions. In adults of the Common Loon, Yellow-billed Loon {Gavia adamsii) , and Arctic Loon ( G. arctica) remigial replacement occurs in late winter while the birds are in their winter range. Glen E. Woolfenden selected. 416 (Jlcn E. Vi’oolfciulen WING MOLT IN LOONS 417 Of the more than 40 dead Common Loons I have found along the beaches in Florida from November through June, eight were flightless, and these eight were all February birds. Features of the life history of loons suggest some of the selective forces that may have brought about the delay of the remigial portion of the prebasic molt. The Common Loon will be used to present these ideas since more is known about its biology, primarily through the work of Olson and Marshall (1952), than is known about the other three species. Common Loons reach the breeding lakes in Canada and northern Lnited States from mid-May to the latter half of June. After arriving at least two weeks are required to establish a territory, choose a nest site, build the nest, and lay their one or two eggs. Incubation requires another four weeks. Care of the young, which normally continues until they can fly, requires an additional 10 or 11 weeks. Thus even if a pair of Common Loons were to begin breeding at the earliest possible time, mid-May, they would be caring for young until mid-September. With actual cases it is later; Olson and Marshall (op. cit. ) recorded the first flying young on 9 October in Minnesota, which is near the southern limit of the species range. Throughout this more than four-month breeding period the ability to fly is essential, for there are important aerial components in the territorial and pair-bond maintenance displays of the Common Loon. Data are not available for the time interval between loss of the remiges and the regaining of flight in loons, but assuming it is similar to that of other water birds, ducks for example ( Hochbaum, 1944 ) , it would require three or four weeks. If loons replaced their flight feathers on the nesting lakes following breeding it would be impossible for them to leave before late October. But according to Pleva (1957) the lakes in Canada freeze over between mid-September and mid-November, and Hochbaum (op. cit.) states that ice closes the bays at Delta, in southern Manitoba, in late October or early November. Thus under present climatological conditions loons molting their remiges on the breeding lakes after nesting often would be trapped by ice and eliminated from the population. Occasionally even volant loons are trapped in this manner. Boardman (1874 ) reported the human slaughtering of about 30 Common Loons concentrated in a small area of open water in Big Lake, Maine. From these facts one must conclude that a simultaneous remigial molt after breeding, but before migration, is impossible. The advantages of replacing the remiges immediately prior to spring migration probably brought about further delay once the process was post- poned until after departure from the breeding areas. Movement from the nesting lakes to maritime waters is a lengthy procedure for many individuals ( Palmer, op. cit. ) , and it is not safe for loons to become flightless on any body of water that might freeze over. Trautman (1940), for example, lists 418 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 the first week in December as the time of departure of Common Loons from Buckeye Lake in Ohio. An additional advantage is that late winter molt assures unworn feathers for the flight north and the ensuing aerial displays. A temporary loss of the remiges while in their maritime wintering quarters is probably advantageous to loons. A reduced pectoral appendage benefits wing-propelled divers ( Storer, op. cit. ), and loons occasionally use this means of subsurface locomotion (Townsend, 1924). Furthermore, temporary loss of even a few buoyant feathers, and a slightly reduced cross-sectional area would be of some advantage to a foot-propelled diver. Adult Red-throated Loons (Gavia stellala) and the immatures of all four species replace their remiges in summer or fall. The need for a delayed simultaneous wing molt is not as great in the Red-throated Loon for the reduced wing loading virtually eliminates the chance of their being trapped by ice. A number of observers even have seen the species take flight from land {in Palmer, op. cit.) ! Furthermore, Red-throated Loons are decidedly more coastal than the other species, particularly during migration and in winter. According to Godfrey [in Palmer, op. cit.) the time of the simulta- neous remigial molt in this species is from early August to November. Immature loons of all four species replace their remiges simultaneously in summer (late May to early August in G. imrner). But these non-breeding loons do not fly to the nesting lakes; instead they normally remain on salt water where need for wings is negligible. Thus these exceptions add strength to the hypothesis that factors associated with breeding and migration have caused the winter remigial molt in adults of the three large species of loons. Use of the morphogenetic law would suggest that the primitive condition was one of a summer wing molt, and that selection indeed has delayed the process in adults. The seeming necessity for a post-migratory simultaneous wing molt in loons brings up the question of how other water birds, namely waterfowl and grebes, nesting in the same area are able to survive with a simultaneous wing molt that precedes fall migration. Data obtained at Delta, Manitoba, by Hochbaum (op. cit.) provide the answer for ducks. Males desert the females in mid summer, change into a less conspicuous eclipse plumage and replace their flight feathers well before they are needed for migration. Females continue to care for the young, but only until the first week in August when they desert the broods, no matter how immature, and replace their remiges before freeze-up. Geese undergo their wing molt while caring for the young (Kortright, 1943). Unfortunately little is known about molt in grebes although it seems certain that some forms, Aechomophorus for example, do shed their remiges simultaneously prior to fall migration ( Pal- mer, op. cit.). The apparent absence of display flights ( Storer, 1963) would Glen E. Woolfeiulen WING MOLT IN LOONS 419 allow breeding and wing molt to occur simultaneously, although this is conjecture, and it may be that other factors are involved. SUMMARY It is suggested that adult Common Loons, and probably adults of the two other large species of Gavia, cannot have a gradual wing molt for structural reasons, and cannot have a simultaneous wing molt while on the breeding lakes for behavioral and cli- matological reasons combined. The only remaining possibility is a simultaneous molt of the remiges following fall migration. Additional selective factors have caused further delay until finally the gaining of new flight feathers immediately precedes spring migration. ACKNOWLEDGMENTS I am grateful to Kenneth C. Parkes and Sievert A. Rohwer who read and improved earlier versions of the manuscript. LITERATURE CITED Boardman, G. a. 1874 A loon-atic on ice. Forest and Stream, 3:291. Delacour, J. 1954 The waterfowl of the world. Vol. 1. Country Life Ltd., London. Hochbaum, H. a. 1944 The Canvasback on a prairie marsh. The Stackpole Co., Harrisburg, Penna. Humphrey, P. S., and K. C. Parkes 1959 An approach to the study of molts and plumages. Aak, 76:1-31. Kortright, F. H. 1943 The ducks, geese and swans of North America. The Stackpole Co., Harrisburg, Penna. Murphy, R. C. 1936 Oceanic birds of South America. Vol. 2. The Macmillan Co., New York. Olson, S. T., and W. H. Marshall 1952 The Common Loon in Minnesota. Occas. Paper No. 5, Minnesota Mus. Nat. Hist. Palmer, R. S. 1%2 Handbook of North American birds. Vol. 1. Yale Univ. Press, New Haven and London. Pleva, E. G., ed. 1957 The Canadian Oxford school atlas. Oxford Univ. Press, Toronto. Savile, D. B. 0. 1957 Adaptive evolution in the avian wing. Evolution, 11:212-224. Storer, R. W. 1960 Evolution in the diving birds. Proc. Xllth Internatl. Ornith. Congr., pp. 694^707. 1963 Courtship and mating behavior and the phylogeny of the grebes. Proc. XIII th Internatl. Ornith. Congr., pp. 562-569. Sullivan, J. 0. 1965 “Elightlessness” in the Dipper. Condor, 67:535-536. Townsend, C. W. 1924 Diving of grebes and loons. Auk, 41:29-41. 420 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Thautman, M. B. 1940 The birds of Buckeye Lake, Ohio. Misc. Publ. Mus. Zool., Unit. Michigan, Van Tyne, J., and A. J. Behgek 1959 Fundamentals of ornithology. John Wiley and Sons, Inc., New York. WiTiiEKBY, H. F., F. C. K. JouKDAiN, N. F. Ticeiiuhst, and B. W. Tucker 1940 The handbook of British birds. Vol. 4. H. F. and G. Witherhy Ltd., London. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF SOUTH FLORIDA, TAMPA, FLORIDA. 9 SEPTEMBER 1966. New Brunswick, and upon bird photography. He has been a longtime contributor to Audubon Field Notes. Dr. Edwards is married and has four children. No. 44. NEW LIFE MEMBER w Dr. Kenneth F. Edwards of Collins Bay, Ontario is a new Life Member of the Wilson Ornithological Society. A holder of an M. D. degree from the University of Toronto, Dr. Ed- wards is an anesthesiologist at Kingston General Hospital. He is a member of the AOU, the National Audubon Society, the Canadian Au- dubon Society, and the Federation of Ontario Naturalists. His orni- thological interests have been cen- tered on the study of migration particularly on Grand Manan Island, ROOSTING BEHAVIOR OF THE HERRING GULL IN CENTRAL MAINE Ralph W. Schreiber COMMUNAL roosting and the environmental conditions affecting roosting have long interested ornithologists. This paper investigates the environ- mental factors influencing the roosting of the Herring Gull [Larus arg,entatus) population in the upper tidal reaches of the Penobscot River, near Bangor, in central Maine from July through November 1965. Cullen ( 1964 ) reviews the roosting habit in birds and concludes that roosting affords protection and is a means of maintaining the body tempera- ture. Wynne-Edwards ( 1962 ) feels that the primary function of roosting is to bring together the members of a bird population for a continuous seasonal epidiectic ( “meant for display” ) demonstration, similar to that which occurs during the breeding season, and that as a result of this display, adjustment and regulation of the population density occurs. Environmental conditions affecting roosting are: time and light intensity, of primary importance in controlling roosting, with the time of roosting varying during the year as the daylight period changes; the amount of cloud cover and its effect on light intensity influences the time of roosting in some species; temperature, wind, social interactions, and other factors usually have little direct effect, but may have some indirect influence in certain situations; and, different species may vary in their response to similar environmental conditions. METHODS The roosts were located by observing the direction in which the gulls flew when leaving feeding areas and “clubs.” “Club” is defined here as the gathering of gulls during the day when they are not actively feeding. While in the club, the gulls spent their time preening, sleeping, or otherwise loafing. The major feeding spots in this study region were the municipal refuse dumps of Bangor, Orono, and Old Town. These dumps lie in an irregular line from NNE to SSW with approximately five miles between the Old Town and Orono dumps, and three miles between the Orono and Bangor dumps. Each dump had a clubbing area close by, usually an open field within a half mile. A banding and marking study showed that the gulls frequenting these dumps and clubs make up a relatively discrete population ( Schreiber, 1965 ) . During July and August, this population flew to a small group of rocks and an old grounded raft in the Penobscot River within the town limits of Orono (the summer roost). In September, October, and November the flight lines 421 422 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 from the dumps and clubs led to Pushaw Lake, a small lake five miles west of Orono (the fall roost). Sunset was used as a constant throughout the study and observations were begun daily at two and a half hours before sunset. For recording data, this period of observation was divided into five minute intervals. All birds present at the roost were counted at the beginning of the period and individual birds were counted as they arrived throughout the observation period. Light intensity was measured with a Weston Illumination Meter ( Model 756 with Quartz filter ) aimed directly overhead. Observations were made so that the sky overhead and to the west was not obscured by shadows and so all direc- tions from which the gulls arrived could be observed. Cloud cover was rated as clear (no clouds), partly cloudy, or cloudy (solid cloud cover with no breaks ) . Temperature was recorded in degrees Centigrade. The wind for the day was rated as calm, medium, or strong. The five minute intervals of observation were divided into half-hour groupings for analysis. Using the total number of birds arriving on a specific day, the percentage of birds arriving in each thirty minute interval of that day was calculated. The days were then grouped according to cloud cover and the average percentage of arrivals for each type of day was calculated using the inverse sine transformation. The Orono roost was observed from 10 July to 29 August, on six cloudy, seven partly cloudy, and four clear days for a total of 17 days. The Pushaw roost was observed on 31 days from 19 September to 27 November, consisting of 14 cloudy, 11 partly cloudy, and six clear days. OBSERVATION Number of birds utilizing the roosts. — In Figure 1 are given for the two roosts the average number of arrivals up to dark (the time when I could no longer be accurate in counting arriving birds) for two or three days of observation. A decline in the Orono roost population occurred through July and August until 25 September, after which no birds were seen at this roost. The number of birds utilizing the Pushaw roost steadily increased during September until a peak was attained during the second week of November, but on 27 November and thereafter the Pushaw roost was not used con- sistently. The number of birds feeding in the study area was lowest during the first two weeks of August, when the roosting population was also the lowest. As the feeding population began to increase during the last two weeks of September, the Orono roost was at a minimum while the Pushaw roost enlarged in numbers. From June through Labor Day weekend, Pushaw Lake is highly congested with summer residents and there is much motorboat activity even after dark Ralph w. HERRING GULL ROOSTING BEHAVIOR 423 Schreiber 10 14 1627 59 10 12 1317 2025 2729 14 23 25 19 23 25 30 2 4 511 1219 21 26 28 31 1 2 711 1415 16 20 27 DATE Fig. 1. Seasonal fluctuations in the numbers of gulls using two roosts near Bangor, Maine between 10 July and 27 November 1965. making it an unsuitable roosting site. The Orono roost, on rocks in the swift flowing river, can hold only so many birds per night. During the summer the 300 to 400 gulls in the area can rest comfortably in Orono, but in the fall, when the population is building up to over 4,000 birds, they must move to a place with greater area. After Labor Day weekend, there are few boats on Pushaw Lake and the shores are relatively deserted. The gulls, a gregar- ious species, all go to Pushaw where the entire population can spend the night on the water in relative quiet. No birds were observed during the night on Pushaw in the summer and none came to Orono after 25 September. When the gulls left Pushaw on the morning of 27 November, after a very calm, cold night, there was a thin film of ice on the lake. That night the gulls moved down the Penobscot River to roost. During the following two weeks Pushaw was alternately open and frozen, and, depending on the condi- tion of the water, the gulls either spent the night there or moved to the river. By 6 December the lake was completely frozen and the birds stopped going there at night. 424 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Roosting llip^hls. — Wind velocity and time of arrival had a pronounced effect on the mode of flight to the roost. On still days the gulls arrived at the Pushaw roost from the dumps and cluhs with a direct flajiping flight or with an easy flapping and gliding while overland. When over the edge of the lake, they began a long straight glide to the flock of gulls already on the water. The gulls gathered in a flock about 400 yards out from the southern edge of the lake. If the birds did not glide directly to the flock, they would fly over the flock and then spiral down to the water. At the Orono roost, the birds invariably flew over the rocks and circled back, turning their heads sideways as if picking out a suitable spot for landing. At both roosts on still days, the early flights ( two hours to a half hour before sunset ) were at an estimated height of 50 to 150 feet above the trees. When the wind was blowing in the direction of the roosting flights, the birds tended to glide and soar a great deal. When the wind opposed the direction of flight, the flying appeared labored and was very erratic in its direction. The stronger the wind, the more erratic became the flight. In a strong wind, the gulls flew very close to the tree tops ( 5 to 35 feet ) . During the fall, upon reaching the edge of Pushaw Lake, the gulls would drop quickly down to about three feet above the water and then proceed to the gathering flock. Many of the gulls would fly along the lee shore of the lake until reaching the point of land nearest the flock. During windy weather the gulls flying to the roost in large flocks tended to fly less compactly than on a calm day. During the summer the gulls tended to come to the roost, throughout the arrival period, singly, in pairs, or in small groups of between 10 and 30 birds, with a slight increase in group size near dark. During the fall, with few birds arriving early, the gulls tended to fly to the roost in massed groups, often numbering as many as 600 birds in one flock. The summer roost flights were not as direct as in the fall and the gulls did more circling and towering on updrafts. At both seasons the gulls leaving the dumps and clubs either flew directly toward the roost at about 50 to 150 feet or would circle up to about 500 feet from whence it appeared that they glided and flapped in a straight line to the roost. This roosting flight seemed quite “purposeful” and I felt that I could tell very soon after a bird took off if it was going to the roost rather than just changing places in the dump or moving to the club. Display flights. — During the later weeks of October and through Novem- ber, as the population at Pushaw built up, there was mass circling above the roost site. At this time the early arrivals gathered together at the southern end of the lake. As darkness approached and the number of birds present 425 Ralph w. HERRING GULL ROOSTING BEHAVIOR bchreii)er Fig. 2. Percentages of arrivals during half hour intervals with sunset as a parameter at the Orono roost by gulls between 10 July and 16 September 1965. increased, the whole flock would rise and wheel in circles. Usually, a majority of the birds would then move north to settle farther up the lake. The re- mainder would settle again on the water in the original gathering site. By sunset all of the birds would have moved north and the late arrivals flew directly toward this northern congregation. At the Orono roost there was little movement within the roost once the birds had settled, and no mass display flights were observed unless the gulls were disturbed. P re- flight activity. — The birds leaving the club for the roost also exhibited a type of social interaction. The gulls gathered in the clubs were quite still, either sitting quietly or sleeping, during most of the afternoon. As the light failed, a number of birds would begin to preen, stretch, stand up, and walk around. It appeared as if the birds grouped closer together. The intensity of the movement increased as more birds became active and after about ten minutes of this activity a number of birds would take off and fly toward the roost. The birds which took off first were those which had been more active. Usually several birds which had not been “restless” would fly up and follow the leaders. A period of quiet would ensue and after five to ten minutes the activity would begin again and the sequence would he repeated. The number of birds leaving during each sequence increased as darkness approached until only four or five birds remained. These either left as individuals or as a group when the light intensity was near zero. Each time 426 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Fig. 3. Percentage of arrivals during half hour intervals with sunset as a parameter at the Pushaw roost by gulls between 17 September and 27 November 1965. the club was observed, this type of behavior was noticed. Miskimen (1955 ) also found a distinct pre-roosting activity in ducks. If the birds were disturbed (either while feeding or in the club) early in the day, the flock would take off, circle and the majority would again land and resume their activity. If the club was disturbed, all of the birds took off, circled, and landed again at a “safe” distance. Again, none moved toward the roost. This behavior was observed during the day until about an hour and a half before sunset or until a light intensity of below 900 foot candles was reached. Once this threshold was reached, and the birds were disturbed, a number could be seen heading toward the roost. As sunset approached and/or the light intensity dropped below 900 foot candles, more and more of the flock would go to the roost. It was possible on some days to disturb the birds enough so that they would all leave for the roost well before the usual time. Roost flights and environmental conditions. — The time of roosting by the gulls in this region appears to be controlled by light intensity and the length of daylight. Figures 2 and 3 show the percentage of the total roost population arriving Ralph W. Schreiher HERRING GULL ROOSTING BEHAVIOR 427 Fig. 4. Percentage of arrivals during the two and a half hours before dark plotted against the log. of light intensity measured in foot candles. At the Orono roost between 10 July and 16 September 1965. during half-hour intervals with sunset time treated as a constant throughout the observation period. At the Orono summer roost (Fig. 2) no difference at the 95 per cent confidence level exists between the percentage of birds arriving on cloudy, partly cloudy, and clear days at the respective time intervals. At the Pushaw fall roost (Fig. 3), a significant difference exists between cloudy and clear days, P > 0.05. During the summer at two hours before sunset between 25 and 28 per cent of the arriving birds were already present at the roost. At the fall roost only four to nine percent of the arriving birds were present two hours before sunset. There is a significant seasonal difference between these early arrivals, P > 0.05. Figures 4 and 5 show the percentage of birds arriving during half-hour intervals, plotted against the logarithm of light intensity. At the Orono summer roost (Fig. 4) a slight peak in the arrivals was reached at sunset, but a fairly constant number of birds arrived throughout the period, with a distinct drop after sunset on cloudy days. The clear day arrivals stay quite high at the lower light intensities. A different situation exists at the fall roost (Fig. 5), however. Here, between 80 and 85 per cent of the birds arrive at the roost at light intensities lower than 300 foot candles. On cloudy days the light intensity drops from 300 to zero foot candles over a period of one hour, but on partly cloudy days and clear days the same change occurs over a period of 30 minutes (Fig. 6). The arrival percentages reached a distinct peak at sunset. Again, cloudy day arrivals dropped off distinctly after sunset but the partly cloudy and clear day percentages remained high at the very low light intensities. During July and August the time between sunrise and sunset was 14 to 428 THE WILSON BULLETIN Dec^emher 1967 Vol. 79, No. 4 Fig. 5. Percentage of arrivals during the two and a half hours before dark plotted against the log. of light intensity measured in foot candles. At the Pushaw roost between 17 September and 27 November 1965. 15 hours. During October and November this time was 9.5 to 10.5 hours. In August, twilight lasted for 45 minutes after sunset but by the end of October it was dark within 15 minutes after sunset. As far as I was aware, all birds arrived at the roost before complete darkness and there was a distinct reduction in the number of arrivals at light intensities under two foot candles. DISCUSSION From the above observations we can draw some conclusions about environ- mental conditions and their role in affecting roosting behavior in the Herring Gull in central Maine. Season of the year. — The season of the year has the most marked effect on the time of roosting. During the summer when the days are long and the temperature is moderate to warm, the gulls tend to move to the roost quite early relative to sunset and at times when the light intensity is high ( above 2,000 foot candles ) . During the shorter, cool days of fall, the gulls do not move to the roost until nearly dark, when the falling light intensity causes the roosting flights to occur. There is little seasonal change in the amount of food present in the dumps in this region but with the longer foraging time available during the summer the gulls probably become satisfied more quickly than during the winter and so move to the roost when satisfied rather than remain at the feeding areas until dark. With the shortening day length and the longer, cold nights of fall, the physiological demands involved 1 w. ■iber 2250 2000 1750 1500 1250 1000 750 500 250 IG. 6. clear HERRING GULL ROOSTING BEHAVIOR 429 TIME Changes in light intensity measured in foot candles on cloudy, partly cloudy, days during the two hours preceding sunset from 17 September to 27 430 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 in maintaining the body temperature are more stringent and it seems that there is an increased utilization of available light for feeding. Li^ht intensity. — During the fall the majority of the gulls arrive at the roost when the light intensity falls below 300 foot candles, with a peak of arrivals being reached between 115 and ten foot candles. Summer roosting does not appear to be controlled so directly by light intensity but, with approaching darkness, there is a peak in the arrivals at the roost between 50 and five foot candles. Hiller’s observation (cited by Kellogg and Hutchin- son, 1964) that gulls moved toward the roost during an eclipse in July but returned to feed after the light returned would confirm that light intensity may still be a factor during the summer, even though not as strong a stimulus as during the periods of shorter day length. In the summer there is no difference between clear and cloudy days in terms of rate of arrival. However, during the fall, on cloudy days significantly more birds arrive at the roost early than on clear days. Wind, temperature, and social factors. — Wind velocity and direction appear to have little effect upon the time of roost flights. Schnell (1965 j has recorded the flight speed of gulls at a breeding colony under varying wind velocities, using a Doppler type radar unit. Assuming his data will also hold for gulls away from the colony, the gulls leaving the major dump and club in this study region would take approximately 12 minutes to reach the roost on a still day, 16 minutes flying into a wind of up to 15 mph, and 8 minutes flying with such a wind. Gulls in this study area did not leave any earlier for the roost on windy days than on calm days even though it took them longer to reach the roost on such days. Temperature does not have a direct effect on roosting time but indirectly affects the time of roosting by its effects on maintenance of body temperature. Disturbances at the feeding and clubbing areas tend to cause earlier departure to roosting sites and there is an element of social interaction in the gulls leaving the clubs. The above data suggest that there is a specific light intensity threshold for roosting in the individual gull but that this may be modified by many factors in the environment. This hypothesis cannot be verified in a field experiment but it would be interesting to test it with birds under controlled laboratory conditions. SUMMARY 1. During the summer and fall of 1965 the roosting behavior of Herring Gulls in central Maine was studied with a view of attempting to correlate this behavior with environmental factors. 2. The summer roost was on rocks in the swift flowing Penobscot River within the town limits of Orono. The fall roost was five miles distant on Pushaw Lake. 3. During the summer the Penobscot River roost was used by up to 400 gulls hut Kalpli W. Sclireihor HERRING GULL ROOSTING BEHAVIOR 431 by 25 September no birds roosted there. Beginning in September the roost at Pushaw Lake was used and by the middle of November as many as 4,000 gulls were using this roost. When the ice formed on the lake no gulls spent the night there. These changes in the location of the roost are explained in relation to the numbers of gulls in the area and the human activity on the lake. 4. A significant difference exists between the time of roosting during the summer and fall. During the summer the gulls roost earlier relative to time of sunset than during the fall. These differences are probably caused by changes in the physiological needs of the gulls and by the changes in day length. 5. During the fall the majority of the gulls arrive when the light intensities are under 300 foot candles; a peak movement is reached between 115 and ten foot candles. 6. During the summer the rate of arrival does not vary between clear and cloudy days, but during the fall significantly more birds arrive at the roost earlier on cloudy than on clear days. 7. Wind velocity and direction, and temperature do not have a direct effect on roost- ing time, but may have an indirect effect. 8. Social interaction and disturbances at the feeding and loafing areas of the gulls may hasten roosting flights. ACKNOWLEDGMENTS The results reported here are a portion of a thesis submitted while a candidate for the Master of Science degree in zoology at the University of Maine, Orono. Many people at that institution were helpful to me during this study. I would especially like to thank Dr. Wm. H. Drury, Jr., of the Massachusetts Audubon Society for his interest and many helpful suggestions. This study was partially supported by a research grant from the Massachusetts Audubon Society, a Grant-in-Aid of Research from The Society of the Sigma Xi, and a contribution from the Mae P. Smith fund of the American Museum of Natural History. LITERATURE CITED Cullen, J. M. 1964 Roosting. In A new dictionary of birds, Ed. by A. L. Thomson, T. Nelson Ltd., London. Kellogg, P. P., and C. M. Hutchinson 1964 The solar eclipse and bird song. Living Bird, 3:390. Miskimen, M. 1955 Meteorological and social factors in autumnal migration of ducks. Condor, 57:179-184. SCIINELL, G. D. 1965 Recording the flight speed of birds by Doppler radar. Living Bird, 4:79-87. SCHREIBER, R. W. 1965 Seasonal population fluctuations and roosting behavior of the Herring Gull in central Maine. (MS Thesis, The University of Maine, Orono.) Wynne-Edwards, V. C. 1962 Animal dispersion in relation to social behaviour. Hafner Publishing Co., New York. DEPARTMENT OF ZOOLOGY; UNIVERSITY OF MAINE, ORONO, MAINE (PRESENT ADDRESS: SMITHSONIAN INSTITUTION PACIFIC PROJECT, WASHINGTON, D. C., 10 MAY 1966. VARIATION IN THE BREEDING SEASON AND CLUTCH-SIZE OE THE ROBIN IN THE NORTHEASTERN UNITED STATES AND THE MARITIME PROVINCES OE CANADA' Deborah V. Howard This paper summarizes an analysis of nest record cards of the Robin ( I Urdus migratorius ) for variations in breeding season and clutch-size. Although these variations have been studied in detail for several species of European birds, very little similar work has been done in North America, partly because the available data were widely scattered and difficult to obtain. The North American Nest Record Card Program at Cornell University, organized to make a centralized source of records available to workers throughout the continent, should provide the stimulus for additional work here. Many important variations are apparent only when the number of rec- ords is very large. There are, however, numerous sources of error in data collected by many observers. These are lucidly discussed by Myres ( 1955 ) and Snow ( 1955 a, h ) in their papers on breeding season, clutch-size, and nesting success in three species of thrushes (Blackbird {Turdus meriila). Song Thrush (T . ericetorum) , and Mistle Thrush (T. viscivorus) ). Burton and Mayer-Gross (1965) have recently compiled a list of papers based on records from the British Nest Records Scheme. These have been most helpful and merit careful study by anyone analyzing nest cards. Unless otherwise stated, it should be understood that Robin refers to the American Robin, and not the European Robin (Erithacus riibecula). METHODS A total of 1,605 records, collected in Massachusetts and New York states and the Maritime Provinces of Canada ( New Brunswick, Nova Scotia, and Prince Edward Island) in 1963, 1964, and 1965, were used. The records from New York were loaned by the North American Nest Record Card Program at Cornell and those from the Maritime Provinces by the Maritimes Nest Record Scheme at Sackville, New Brunswick. All the records for Massachusetts (with the exception of 7 from Cornell ) were collected by the Massachusetts Audu- bon Society as part of their Robin Nest Survey. Figure 1 shows the distribution of records by counties. The most heavily represented areas are those nearest the record collection centers: western and southern New York around Ithaca, eastern Massachusetts around Lincoln, and ^ Contribution No. 56 from the Hathaway School of Conservation Education, Massachusetts Audubon Society, Lincoln, Massachusetts 01773. 432 ih V. (1 ROBIN BREEDING SEASON AND CLUTCH-SIZE u H D h-l U ^ S w H-l o <1 < ^ 5 o 0; iz; . _ W) 0) is s C3,C I— , i5 > S o 0) 1| (U c oj a I i s :s F’ 3 m - csi O S 433 Island 3.1 ± 0.07 0.53 52 3.0 ± 0.15 0.71 (73 clutches) 434 I HE WILSON BULLETIN December 1967 Vol. 79, No. 4 Fig. 1. Geographical distribution of nest records from Massachusetts, New ’b;ork, and the Maritime Provinces. the central Maritime region around Sackville. The less populated areas are poorly represented. The criteria used for inclusion and dating of records were a modification of those of Myres and Snow. A total of 1,167 nests were available for analysis of clutch-size. All nests containing eggs were used except that obviously in- complete clutches and all clutches of one were excluded, as were nests con- taining hatched young together with infertile eggs. Those nests found during laying and closely watched until the clutch is complete give the most nearly accurate figures. These comprised one quarter of the cards. The remaining three quarters were nests found during the incubation period. About one fifth of these were visited only once. Because some incomplete clutches and some clutches which had lost eggs were doubtless included, all the figures given for clutch-size are probably low. They are therefore suited for comparative purposes, but caution should be used in drawing conclusions from the ab- solute values. Nests were dated from the day the first egg was laid. For those found during laying, the initial date could be figured most accurately. If the hatch- ing or fledging date or the age of the young was given, the initial date could 435 Deborai. V. RQBIN BREEDING SEASON AND CLUTCH-SIZE Howard be calculated less accurately using an average incubation period of 13 days and an average nestling period of 13 days (Young, 1955; pers. obs.j. Nests visited more than once during the incubation or nestling period with none of the above dates given were dated using the bracketing method of Myres: the earliest and latest dates on which the hatching or fledging could have occurred were calculated from the observations. The date when the clutch was started was then estimated from the median date between them. The largest possible bracket was 12 days, with an error of plus or minus six days from the middle date. Nests visited only once, with no additional information given, were assumed to be in the middle of the incubation or nestling period ( D. Lack, 1946; E. Lack, 1950). Nests could also be dated if the banding date was given, as the young birds are usually banded when they are 7 or 8 days old. Once dated, the nests were grouped into 5-day periods for description of the breeding season. Although 40 per cent of the cards were dated using brackets, most of these were smaller than the maximum of 12 days. There is nevertheless the possibility that some were placed in the wrong 5-day period. CLUTCH-SIZE Robins usually lay a clutch of three or four eggs. Casual description of the clutch-size as three to five is misleading, as only 2 per cent of the clutches in Massachusetts and New York and less than one per cent in the Maritimes consist of five eggs. Most clutches of one and two are probably the result of disturbance or actual predation during laying, although it is probable that clutches of two are more common in the Maritimes (see below). Nests con- taining more than five eggs have been reported, but are apparently the result of multiple nesting or erratic behavior on the part of a single female (Young, op. cit. ; Howell, 1942 ). The Brown-headed Cowbird {Molothrus ater) lays in Robin's nests occasionally, but the Robins customarily remove the egg (Friedmann, 1929; pers. obs. ) . This results in a lower clutch-size, for the cowbird removes a robin’s egg before it lays its own, and this egg is not replaced. Seasonal variation. — Table 1 shows the mean clutch-size in Massachusetts, New York, and each of the Maritime Provinces by months throughout the nesting season. In all but Massachusetts, the clutch-size is higher in May than in April or June, suggesting a peak during that month. Further, the majority of clutches of five reported were begun in May. The rise between April and May is not statistically significant ( using a two-sided T test, with a confidence limit of 95 per cent), nor is the drop from May to June except for Massa- chusetts and New Brunswick. The difference between May and July, however, is significant for all areas but Nova Scotia. The difference in all cases is small, being on the order of half an egg. 436 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Pekcentagk Distribution Table 2 OF Clutch-sizes in Massachusetts-New Maritime Provinces York and the Clutch- Mass. -New York Maritimes size per cent per cent 5 2 1 4 50 38 3 41 45 2 7 15 Total number of clutches 762 405 Lack (1946), Monk (1954), Peakall (1960), and Snow (1955a) using British nest records, have found that clutch-size for the European Robin, the Yellowhammer (Ernberiza cilrinella) , the Greenfinch [Chloris chloris), and the Blackbird and the Song Thrush rises to a peak in May or June and then declines. That of the Robin apparently also follows this pattern, although the initial rise is much less pronounced than the later decline. The Robin does not begin to lay until late April. In contrast, the Blackbird, which lays its first eggs in March in Great Britain, shows a gradual rise in clutch-size from March until mid-May, after which it declines. Lack (1954) has pointed out that the clutch-size of many double-brooded passerines reaches a peak in May or June. He suggests that this seasonal variation in clutch-size has come about through natural selection and results in the production of the most young possible. The proximate factors influencing the variation are changes in day-length and the availability of food for the young throughout the breed- ing season. Geographical variation. — The percentage distribution of clutch-size in Mas- sachusetts-New York and the Maritime Provinces is shown in Table 2. The most common clutch-size in the Maritimes is 3, while that in Massachusetts- New York is 4. Clutches of five are less than half as frequent in the Maritimes and there are twice as many clutches of two. Clutches of two are more or less evenly distributed through the season in Massachusetts-New York, supporting the theory that many of them are due to predation (Snow, 1955a), but there is a sharp rise in the number of clutches of two in the Maritimes late in the season. The overall mean clutch-size for the Maritime Provinces is 3.2 ± 0.04. This differs significantly at 99 per cent confidence limits from the overall mean for Massachusetts-New York, which is 3.5 ± 0.02. Moreover, the mean clutch-size declines steadily from New Brunswick (3.3 ±0.05 ) to Nova Scotia (3.2 ±0.06) to Prince Edward Island (3.0 ± 0.10). This tendency persists on the island of Newfoundland, where, out of more than 70 Robin nest records, only 4 were found to contain 4 eggs or Deborah Howard ROBIN BREEDING SEASON AND CLUTCH-SIZE 437 Table 3 Annual Variation Variation in mean monthly clutch-size each year from the overall in Massachusetts-New York monthly mean. 1963 1964 1965 All years April 3.6 3.5 3.6 3.5 May 3.6 3.6 3.4 3.5 June 3.0 3.3 3.3 3.3 July 3.0 3.1 3.2 3.2 young (Tuck, pers. comm.) while in Labrador, clutches of 4 are more common (Todd, 1963). Howell (op. cit.) and Young (op. cit. ) each calculated an overall mean clutch-size for the Robin which agrees closely with the overall mean for Mas- sachusetts-New York: Howell at Ithaca, New York (42°N lat) — 3.4, 127 nests; Young at Madison, Wisconsin (43°N lat) — 3.4, 146 nests. It has been shown for a number of species in northern Europe that clutch- size increases with increasing latitude. In the case of the Robin in New York— Massachusetts and the Maritime Provinces, any influence of the increase in latitude is apparently overridden by the more maritime climate in the Prov- inces. Lack (1947, 1948a) and others have commented on the fact that clutch-size tends to be lower in maritime or island situations than in a con- tinental environment. Detailed records for the European Robin and Common Swift (Apus apus ) in Europe show that this is true for these species (Lack, 1954; Lack and Lack, 1951) and Tompa (1964) has shown that this variation holds lor the Song Sparrow (Melospiza melodia) in British Columbia. Gen- erally accepted theory suggests that this is an adaptation to a poorer food supply in maritime as compared with continental environments. Annual variation. — Annual variation in clutch-size has been described for several species of European birds (Lack, 19486; Kluijver, 1951; Snow, 1955a). Table 3 shows the monthly means for Massachusetts-New York for each year and the overall monthly means for all years combined. Although there is a slight amount of variation from the overall mean on each month, in no case is the difference statistically significant. BREEDING SEASON Robins raise more than one brood during a season in northeastern United States and the Maritime Provinces. Howell (op. cit.) estimated that a maxi- mum of one out of seven pairs raised a third brood at Ithaca, New York but I suspect that third broods are rare in the Maritimes, as there were only nine 438 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Table 4 Breeding Season Number of clutche.s begun in each 5-day period in Massachusetts-New York and the Maritime Provinces in the years 1963, 1964, and 1965. 1963 1964 1965 Mass. -New York M.P. Mass. -New York M.P. Mass. -New York M.P. 12-16 April 2 3 1 17-21 4 11 14 22-26 14 1 41 2 40 1 27-1 24 6 59 4 74 8 2-6 May 37 8 50 14 75 19 7-11 17 19 34 27 49 15 12-16 19 18 27 30 51 36 17-21 9 23 39 22 31 36 22-26 9 16 31 15 34 23 27-31 9 15 14 12 17 30 1-5 June 4 7 12 6 27 12 6-10 4 17 17 14 15 22 11-15 5 5 13 15 20 16-20 7 3 13 5 14 10 21-25 6 7 6 2 5 26-30 4 8 8 6 4 July 2 8 21 12 23 6 Mean date of completion of first clutches* 3 May 16 May 2 May 15 May 3 May 17 May * Calculated for Massachusetts-New York using aU clutches begun through 16 May; for the Maritimes, all those begun through 31 May. nests out of 405 reported from the three Provinces which were begun late enough to fall in this category. While nests with eggs are commonly found in New York and Massachusetts in late April, they are rather rare this early in the Maritimes. The great majority (80 per cent) of nests reported from all areas were begun in May and June, with a few in July and one from New York in August (omitted from Table 4). Part of the seasonal decline is an artifact, however, because nests are harder to find and less sought after later in the season. Indeed, Peakall (op. cit.) was able to show that, for the Yellowhammer, this bias shifted the nesting season peak forward by about five days. It probably applies equally to all nest records examined in this study, and they can therefore be compared. The breeding season is approximately 14 days earlier in the Massachusetts-New York area than it is in the Maritimes. Although the weather was compatible with a truly earlier season in 1964, there is not enough information to show whether there is an annual variation. Dehorali V. Howard ROBIN BREEDING SEASON AND CLUTCH-SIZE 439 SUMMARY A total of 1,605 nest record cards from New York and Massachusetts and the Maritime Provinces of Canada were examined for variations in the breeding season and clutch-size of the Rohin, In all areas hut Massachusetts, clutch-size is higher in May than in April or June, suggesting a peak during that month. Clutch-size is significantly lower in the Maritimes than in New York-Massachusetts and declines steadily from New Bruns- wick to Nova Scotia to Prince Edward Island. The breeding season is approximately two weeks earlier in New York-Massachusetts than in the Maritime Provinces. ACKNOWLEDGMENTS I would like to thank both Dr. David B. Peakall of the North American Nest Record Card Program and Mr. A. J. Erskine of the Maritimes Nest Record Scheme for loaning me their original data. Dr. John Kadlec gave me helpful advice about the statistical aspects of the paper, and Mr. James Baird, Dr. William Drury, Jr., and Dr. David Snow read and criticized the original manuscript. The work for this paper was supported, in part, by a grant from Sigma Xi. LITERATURE CITED Burton, J. F., and H. Mayer-Gross 1965 The first 25 years of the nest record scheme. Bird Study, 12:100-107. Friedmann, H. 1929 The Cowbirds. Charles C. Thomas, Springfield, Illinois. Howell, J. C. 1942 Notes on the nesting habits of the American Rohin. Amer. Midland Nat., 28:529-603. Kluijver, H. N. 1951 The population ecology of the Great Tit, Parus m. major L. Ardea, 39:1-135. Lack, D. 1946 Clutch and brood size in the Rohin. Brit. Birds, 39:98-109; 130-135. 1947 The significance of clutch-size. Ibis, 89:302-352. 1948a The significance of clutch-size, Part III. Ibis, 90:25-45. 19486 Natural selection and family size in the Starling. Evolution, 2:95-110. 1954. Tlie natural regulation of animal numbers. Clarendon Press, Oxford. Lack, D., and E. Lack 1951 The breeding biology of the Swift Apus apus. Ibis, 93:501-546. Lack, E. 1950 Breeding season and clutch-size of the Wood Warbler. Ibis, 92:95-98. Monk, J. F. 1954 The breeding biology of the Greenfinch. Bird Study, 1:2-14. Myres, M. T. 1955 The breeding of Blackbird, Song Thrush and Mistle Thrush in Great Britain. Pt. I. Breeding seasons. Bird Study, 2:2-24. Peakall, D. B. 1960 Nest records of the Yellowhammer. Bird Study, 7:94-102. Snow, D. W. 1955a The breeding of Blackbird, Song Thrush, and Mistle Thrush in Great Britain. Pt. II. Clutch-size. Bird Study, 2:72-84. 440 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 1955/1 The breeding of Blackbird, Song Thrush, and Mistle Thrush in Great Britain. Pt. III. Nesting Success. Bird Study, 2:169-178. Todd, W. E. C. 1963 Birds of the Labrador Peninsula. University of Toronto Press, Toronto. Tompa, F. S. 1964 Factors determining the numbers of Song Sparrows, Melospiza melodia (Wilson), on Mandarte Island, B. C., Canada. Acta Zoologica Fennica, 109: 4-73. Young, H. 1955 Breeding behavior and nesting of the Eastern Robin. Amer. Midland Nat., 53:329-352. MASSACHUSETTS AUDUBON SOCIETY, LINCOLN, MASS. 01/73, 15 JUNE 1966 NEW LIFE MEMBER A recent addition to the roll of Life Members of the Wilson Orni- thological Society is Dr. Robert C. Stein, Professor of Biology at the State University College, Buffalo, New York. Dr. Stein has a bach- elor’s degree from St. Olaf College, and a doctorate from Cornell Uni- versity. He has specialized in bio- acoustics and the use of sound as a species isolating mechanism. He has published numerous papers in these fields and is perhaps best known for his work in studying the two differ- ent songs of the Traill’s Flycatcher. Dr. Stein is a member of the AOU, the BOU, the Cooper Society, American Society of Zoologists, as well as several other ornithological and zoological organizations. He is married and has one child. CARE, FOOD CONSUMPTION, AND BEHAVIOR OF BALD EAGLES USED IN DDT TESTS Nicholas J. Chura and Paul A. Stewart A ^ r IDESPREAD concern exists over the decline in numbers of the Bald W Eagle {Haliaeetus leucocephalus ) , our national emblem. In the con- tinental United States there were approximately 3,642 Bald Eagles present in 1961, 3,807 in 1962, and 3,547 in 1963, according to January censuses (Sprunt and Ligas, 1963). A study was undertaken to help determine if pesticides may possibly be one of the factors lowering eagle populations. Feeding experiments were conducted with 27 Bald Eagles in 1962 and 1963 to determine the approximate level of DDT in the diet that might cause death, the rates of accumulation and loss of DDT residues in various tissues, and the effects of DDT on reproductive organs. Results of this work have been reported by DeWitt and Buckley (1962), Buckley and DeWitt (1963), Locke, Chura, and Stewart (1966), and Stickel, et al. (1966). The purpose of this paper is to present information on care, food consump- tion, behavior, and symptoms of DDT poisoning of eagles used in the tests. CAPTURE AND HOUSING Bald Eagles were captured in November and December of 1961 and 1962 along the Chilkat River near Haines, Alaska, where they congregate each year to feed on late-spawning chum salmon. Many shallow channels are bordered by extensive gravel bars littered with uprooted stumps and other drift. Eagles coming from roost trees along the shore often perch on these snags before proceeding to the water’s edge for food. Number IV2 steel traps (single spring and jump type) were loosely wired on snags 1 to 4 feet above the ground and camouflaged with leaves and debris. When the birds alighted and were caught by the toes, the traps pulled free from the snags allowing the birds to fall to the ground. Trap chains stapled to the snag or a drag prevented captured birds from flying off. Captured birds were shipped by air to the Experimental Fur Station at Petersburg, Alaska. Ten eagles were housed in a wooden shed, 120 X 12 feet, built along a chain-link fence on the west side of the station. Perches made from sections of tree trunks were supported by pipes driven into the ground and spaced 8-10 feet apart and 3-4 feet from the rear wall. The legs of the birds were jessed (Michell, 1959) and the jesses were connected by swivel to a nylon leash that had one end looped around the pipe so birds had free movement up, onto, and around the perches. Cake pans were nailed on top and to one 441 442 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 side of each perch to hold similar pans containing food. Water was offered in metal bowls nailed to the wall behind the perches. Because of space limitations, several 1963 birds were housed in wire cages ( 12 X 6 X 5 feet high ) which had small logs on the floor for perches. Food and water were offered in containers placed on the wire floors. BEHAVIOR The eagles were visited frequently for care and observation. When first approached, one or more birds gave a cackling warning. Most birds then dropped to the ground and began pulling against their leashes trying to escape. However, one bird usually stayed on its perch even when being fed and another generally stood on the ground in a low crouched position. Trembling and feather erection, signs of distress, varied in intensity according to the type of disturbance, temperament of the birds, and the degree of adjustment to captivity. Newly captured birds trembled the most. Even after months in captivity they trembled slightly when mildly disturbed. Feather erection usually accompanied trembling. A fluffing out of head and chin feathers occurred when the birds were mildly disturbed. Additional distress caused the erection of wing and back feathers (to about a 45° angle) and abdominal feathers (to a 90° angle). Birds were frequently observed shaking out their feathers. Typically, the birds would stand on their perches with wings partly outstretched. The feathers were then erected and shaken vigorously for a few seconds. Actual preening was not observed, but some birds occasionally appeared to scratch their bodies with their bills. The birds usually cleaned their bills by rubbing them vigorously on convenient surfaces such as the top edges of the perches, or food pans. But one bird dug in the ground with its bill and would mouth the soil and debris without swallowing. Another bird rubbed and whittled on the edges of wooden beams behind its perch as high as it could reach. One bird occasion- ally reached down during a meal to take a talon in its beak, setting the point of the talon in the curve of its upper mandible. Then it pulled on the talon with a side-to-side motion of the head. This may have served to cleanse the inside of the bill, the talons, or both. Birds frequently exercised their wings while standing on perches or on the ground. When on the ground they pulled against their leashes in a controlled and deliberate manner. The digging action of the talons in these exercises caused deep circular grooves to form around the perches. When handled, the eagles instinctively attempted to flip over on their backs, and strike with their talons. They were also able to reach up and strike at a hand near their head if the legs were not restrained. In addition, most birds made use of their sharp and powerful bills to defend themselves. ciuua and EAGLE CARE, EOOD CONSUMPTION, AND BEHAVIOR 443 Stewart HANDLING Untethered birds in cages were best caught with a net. A tethered bird could be restrained and then grabbed safely while it was on the ground by walking on the leash up to its immobilized feet. A leashed bird could also be caught by grabbing its outstretched wings, folding them against its body and stepping back away from the perch to keep the legs extended by the leash. The feet could then be tied, or fitted with a snug leather pouch that prevented use of the talons. For further handling, transporting, or force feeding, the bird could be bound in a rectangular piece of cloth which was tied at the chest and around the tail under the legs to hold the wings firmly against the body. It was necessary to approach and work slowly around the birds because fast movements got them too excited. Their rapid heartbeats could sometimes be heard from several feet away. When handled they emitted high-pitched, ear-piercing screams and panted from their exertion of trying to escape. Only by covering their heads with heavy cloth to blind them could they be calmed and kept relatively immobile during handling. Certain recommendations can be made for preventing injury at capture and increasing the comfort of experimental eagles in captivity: (1) Modify the steel traps by using lightweight number 4 jaws, padded, combined with a number V/2 spring to catch and hold the birds around the tarsus, thus preventing toe damage during capture. (2) When possible, use large cages with wire floors and wooden perches; insert an inner wall of nylon net, which gives upon impact, in the cages of the more nervous birds. This has been tried and found successful. (3) If birds must be leashed to perches, ample space should be allowed around each perch. (4) Place a second swivel, just after the loop connection around the perch upright, to help decrease leash twisting. (5) Shorten the leashes of the more nervous birds to prevent their gaining momentum enough to sprain a leg. ( 6 ) Keep birds isolated and relatively free of disturbance, particularly during feeding periods. (7) Handle birds as little as possible, particularly during the critical adjust- ment period, unless they are to be properly manned. (Our eagles were not manned because of the number of birds and time limitations. EARLY ADJUSTMENT AND VOLUNTARY FEEDING The interim between capture and voluntary feeding on a regular basis was a critical period for the eagles. Prior to the 1963 tests four birds died even after they began taking food voluntarily (Table I ). Important problems of confining wild animals, including those of the transition from freedom to captivity, are discussed by Hediger (1950). 444 THE WILSON BULLETIN Deceniher 1967 Vol. 79, No. 4 Table 1 Voluntary Food Intake by 21 Newly Captured Bald Eagles Held at the Experimental Fur Station, Petersburg, Alaska, for the 1%3 Tests Day at station first food taken Day when ground fish taken alone Bird number _ 77“ 1 1 llA, 14A,89" 6 6 14 7 7 17,19 8 8 11,12,18 9 9 13 10 13, 15 20, 11 11,12 22,15 15 19 23 17 18, 23 21", 87- 18 20 16* 19 23 (#86 only) 8F, 86” Died on 6th dav without taking food; ^ Died on 5th day; Successfully force fed on 4th da>4 I Successfullv force fed on 16th day; * Died on 38th day; ^ Successfully force fed on 16th and 18th day; s Unsuccessfully force fed on 16th day but successfully fed on 18th day. Died on 1.5th day; Successfully force fed on 16th and 18th day. Died on 33rd day. Encouraging the eagles to feed on ground fish regularly was accomplished by offering whole or parts of fish and mammals simultaneously with ground fish (usually pink salmon I . Food was left with the birds day and night so they could sample it at will. Once birds began eating, the daily offering of whole food was decreased until the changeover to ground fish was complete. Five birds had to be force-fed to give them nourishment and to encourage them to feed. Strips of fish ( about 6X1 inches ) were forced down the gullet; when the bird began to swallow, its neck was gently massaged until the meal was completely taken. Because of the stress involved, force-feeding was used only as a last resort measure. DIETS AND FOOD CONSUMPTION Fish from local canneries was ground, packaged, and frozen for stor- age, then thawed for use. At various times during the 1962 (March- June) tests the diet consisted of ground salmon, herring, flounder, and supplements. In the 1963 ( January-May) tests the basic food was ground pink salmon waste. With little variation the regular diet consisted of pink salmon (99 per cent), liver meal ( 1 per cent), multiple vitamins ( 1 teaspoon- ful per 10 pounds of food ) used daily, and Terramycin ( 1 gram active ingredi- ents per 10 pounds of food ) used for periods of about / days and omitted for 3 or 4 days. Chura and EAGLE CARE, FOOD CONSUMPTION. AND BEHAVIOR 445 Stewart ’ ' ^ Table 2 Food Consumption of Captive Bald Eagles Bird number Age Sex DDT dosage level ( PPni ) “ Dosage period ( days ) Daily food consumption ( grams ) Mean ± stan- Range dard error 1962: 1 Adult 0 112 314 ± 14 0-700 10 Immature 9 0 112 288 ± 16 0-700 3 Immature 9 10 98^^ 401 ± 17 0-719 6 Adult $ 10 IT 150 ± 19 0-680 2 Adult $ 160 lY 215 ± 18 0-609 9 Adult $ 160 112 335 ± 14 0-700 5 Adult $ 800 6T 213 ± 20 0-546 7 Immature 9 800 59*= 238 ± 25 0-815 4 Adult S 4000 23'= 198 ± 26 8-490 4A Adult S 4000 15" 109 ± 35 0-344 8 Immature $ 4000 18" 215 ± 32 0-530 1963: 15 Adult 9 0 120 324 ± 9 33-467 12 Adult 9 10 120 265 ± 9 0-484 13 Adult $ 10 120 312 ± 8 0-501 20 Adult 9 10 120 229 ± 8 0-657 22 Adult $ 10 120 204 ± 13 0-500 11 Adult $ 10 60 274 ± 14 93-609 14 Adult S 10 60 219 ± 14 0-465 17 Adult 9 10 60 252 ± 15 0-500 23 Immature 9 10 60 303 ± 19 0-500 14A Adult 9 10 60 194 ± 11 0-449 17A Adult S 10 60 254 ± 20 0-492 llA Adult S 10 39" 252 ± 23 0-499 16 Adult $ 10 & 0 60 & 60 2921 258 [ 275 ± 11 0-703 18 Adult S 10 & 0 60 & 60 2321 176/ 204 ± 9 0-504 19 Adult 9 10 & 0 60 & 60 2291 196] 213 ± 11 0-489 21 Adult $ 10 & 0 60 & 60 2871 252/ 269 ± 12 0-490 ® Dietary’ concentration expressed on a dry- weight basis, on the assumption of 70 per cent mois- ture content. Actual moisture content proved to he 65 per cent. Bird escaped, c Bird died. A uniform blend of all ingredients, including technical grade p,p' DDT dissolved in Wesson oil, was achieved by using a motor driven bread mixer. Food was weighed on a beam balance before and after feeding. Birds were fed about 4:00 pm daily and were generally offered all the food they would eat in about an hour. 446 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 In the 1962 tests 11 eagles ate an average of 271 grams per bird day with a range of 109 to 101 grams per day between birds (Table 2). The wide range between birds on 10 ppm DDT (150 to 101 grams ) was caused in part by bird 6 being long off feed because of illness. Birds that died ate little or no food immediately before death. In the 1963 tests 16 eagles ate an average of 254 grams of food per bird day with a range of 194 to 324 grams per day between birds. Average daily food consumption of birds in two 1963 tests was computed as a percentage of average body weight ( based on mean of near-capture and death weights ) . Females on 10 ppm DDT for 120 days ate at the rate of 4.9 per cent of their body weight, whereas the males ate 6.4 per cent. Similarly, females on 10 ppm DDI^ for 60 days ate 5.0 per cent of their body weight, but the males ate 6.2 per cent. Fevold and Craighead (1958 ) reported a similar sex differ- ence in Golden Eagles (Aquila chrysaetos ) and suggested this might result from differences in basal metabolism. WEIGHT CHANGES Eagles in the 1962 tests were first weighed at time of capture. Seven adult males averaged 10.7 pounds (range 9.3-12.4), one immature male weighed 10.8 pounds and one immature female weighed 12.4 pounds. These weights are higher than the averages reported for other Alaskan eagles by Imler and Kalmbach (1955 ). All 1962 birds, except a control, lost weight between capture and death or sacrifice (Table 3 ). Weight losses for the seven birds that died on dosage varied from 23 to 49 per cent and were probably a result of impaired health due to DDT poisoning. General health may also have been poor, however, for a control lost 14 per cent and bird 6 on 10 ppm DDT died of a lingering illness. For this reason Terramycin was added to the diet in 1963. The 1963 test birds were weighed upon their arrival at the fur station 1 to 13 days after capture during which time they ate little and lost an unknown amount of weight. Thus, valid weight comparisons could not be made. MORTALITY AND SYMPTOMS OF DDT POISONING Tremors attributable to DDT poisoning (Rudd and Genelly, 1965, and others) were evident in all but bird 6 of the 1962 birds that died. The intensity of tremors varied. Tremors generally were stronger (jerking wings and general incoordination simultaneous with vigorous feather shaking) in birds receiving higher dosages, but one bird on 800 ppm DDT and one on 4000 ppm DDT had only mild tremors (slight quivering of tail, wing, or erected body feathers). Cliuia and Stewart EAGLE CARE, FOOD CONSUMPTION, AND BEHAVIOR 447 Table 3 Weight Changes of 1962 Test Eagles Weight ( grams ) Bird number Age Sex Dosage level DDT (ppm)“ Dosage period ( days ) At capture At death Per cent change 1 Adult $ 0 112 4,238 4,252 -f 0.3 10 Immature 9 0 112 4,706 3,955 -14 3 Immature 9 10 98*^ 4,649 - - 6 Adult S 10 IT 4,536 2,211 -49 2 Adult S 160 lY 5,642 3,629 -36 9 Adult $ 160 112 5,273 4,423 -11 5 Adult s 800 62^^ 4,295 3,289 -24 7 Immature 9 800 59'= 5,642 4,026 -29 4 Adult $ 4000 23'= 4,777 3,671 -23 4A Adult S 4000 15'= 5,075 3,444 -32 8 Immature $ 4000 18'= 4,904 3,544 -27 “ Dietary concentration expressed on a dry weight basis, on the assumption of 70 per cent mois- ture content. Actual moisture content proved to be 65 per cent. Bird escaped. Bird died. Tremors and death occurred first for the birds on the highest dosage and progressively later in birds on lower dosages. The 4000 ppm DDT birds showed tremors 12-18 days after dosage began and died at 15-23 days on dosage. It took 34-45 days for tremors to appear on the 800 ppm DDT birds and 59-62 days on dosage for death to occur. Tremors appeared on the 160 ppm DDT birds at 55 days on dosage and one of these birds died at 71 days on dosage. The birds on 10 ppm DDT, including bird 6 that died, showed no evidence of tremors caused by DDT poisoning. The influence on tremors or survival of two days in April when no DDT was fed is not known. The only test eagle that died in 1963 had lesions suggestive of a serious respiratory disease. None of the 1963 birds exhibited tremors attributable to DDT poisoning. SUMMARY Twenty-seven Bald Eagles captured in southeastern Alaska were used in feeding tests to determine the effects of DDT in the diet. Trapping and housing of eagles are discussed. Various aspects of eagle behavior and handling techniques are also presented. Recommendations are made for preventing injuries and increasing the comfort of captive birds. The 1962 test birds consumed an average of 274 grams per bird day with a range of 109 to 401 grams per day between birds. Average food intake was 254 grams per bird day for the 1963 test birds with a range of 194 to 324 grams per day between birds. Weight losses varied from 23 to 49 per cent of normal body weight for the 7 birds 448 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 which died in the 1962 tests. Tremors and death occurred first for birds on the highest dosage and progressively later for birds on the lower dosages. ACKNOWLEDGMENTS Eagles were acquired with the assistance of J. Branson and F. Rohards of the Alaska Regional Office of the Bureau of Sport Fisheries and Wildlife. Many facilities were furnished by J. R. Leekley, director of the Petersburg Experimental Fur .Station, Peters- burg, Alaska. L. F. Stickel, Patuxent Wildlife Research Center, Laurel, Maryland, reviewed the manuscript. LITERATURE CITED Buckley, J. L., and J. B. DeWitt 1963 Progress report, pesticide-Bald Eagle relationships. In A Florida Notebook. National Audubon Society, New York. DeWitt, J. B., and J. L. Buckley 1962 Studies on pesticide-eagle relationships. Audubon Field Notes, 16:541. Fevold, H. R., and j. j. Craighead 1958 Food requirements of the Golden Eagle. Auk, 75:312-317. Hediger, H. 1950 Wild animals in captivity. Butterworths Scientific Publications, London. Imler, R. H., and E. R. Kalmbach 1955 The Bald Eagle and its economic status. U. S. Department of the Interior, Fish and Wildlife Service, Circular 30. Locke, L. M., N. J. Chura, and P. A. Stewart 1966 Spermatogenesis in Bald Eagles experimentally fed a diet containing DDT. Condor, 68:497-502. Miciiell, E. B. 1959 The art and practice of hawking. Charles T. Branford Co., Boston. Rudd, R. L., and R. E. Genelly 1956 Pesticides: their use and toxicity in relation to wildlife. California Game Bull. No. 7:1-209. SpRUNT, a., IV, AND F. J. Ligas 1963 Continental Bald Eagle project. Progress Report No. III. In A Florida Notebook. National Audubon Society, New York. 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. Am. Wildl. and Nat. Res. Conj. 31:190-200. U. S. DEPARTMENT OF THE INTERIOR, NATIONAL PARK SERVICE, OFFICE OF NATURAL SCIENCE STUDIES, WASHINGTON, D. C. ( PRESENT ADDRESS OF P. A. STEWART: U. S. DEPARTMENT OF AGRICULTURE, ENTOVIOLOGY RESEARCH DIVISION, OXFORD, NORTH CAROLINA). 18 MARCH 1966. GENERAL NOTES Goshawk predation on Sharp-tailed Grouse in the Nebraska sandhills. — There are few observations of Goshawks i Accipiter gentilis) preying on prairie grouse. Moran (1966. Auk, 83:137) observed a Goshawk kill a Greater Prairie Chicken [Tympunuchus cupido) in Wisconsin; this grouse was preyed upon in an area where it had taken refuge after being flushed from a booming ground. Ammann (1959. J. Wildl. Mgmt., 23: 110-111) found a Goshawk feeding on a freshly killed male Sharp-tailed Grouse i Pedioecetes phasianellus) on a Michigan dancing ground; and Berger, Hamerstrom, and Hamerstrom (1963. /. Wildl. Mgmt., 27:778-791) observed a Goshawk feeding on the hot carcass of a Greater Prairie Chicken on a booming ground in Wisconsin. On 7 April 1966, I witnessed Goshawk predation on a Sharp-tailed Grouse on Display Ground 11 on the Bessey District of the Nebraska National Forest, Thomas County, Nebraska. The National Forest is located in the Sandhills and is described in a previous report (Blus, 1966. Nebraska Bird Rev., 34:23-30). A male juvenile sharptail, which had flown from the display ground when I arrived by automobile at 6:15 am, was taken by an immature hawk 100 yards from the display ground. The Goshawk, flying at an altitude of approximately 4 feet, hit the grouse on the ground. The grouse dragged the hawk for short distances on several occasions in attempting to escape. The hawk began to pull feathers from the breast of its prey about 10 minutes after the strike; the dead sharptail was taken from the hawk at this point. In five years of prairie grouse study on the 90,000-acre National Forest, observations of seven single Goshawks and one pair were recorded; Goshawks were observed in four of the five years. Only two of these birds were seen in the 25,000 acres of planted coniferous plantations. In addition to the spring kill mentioned above, three hawks (a single and a pair) were observed feeding on two sharptail carcasses in winter; one hawk was relieved of a captured sharptail in winter; two were seen harassing sharptails on display grounds during spring; one was observed in late August flying over an area from which I flushed seven sharptails a few seconds previously; and one was not associated with either harassment or kill of Sharp-tailed Grouse. Karl Menzel (pers. comm.) rescued the captured sharptail mentioned above from a Goshawk in a coniferous plantation; the grouse was not seriously injured and was eventually released. Grange (1948. “Wisconsin Grouse Problems,” p. 124) included the Goshawk among the most skillful grouse predators in Wisconsin; this also seems to hold true for Nebraska where Sharp-tailed Grouse are apparently among the preferred prey of this raptor. Appreciation is expressed to Karl Menzel, C. Phillip Agee, and Carl Wolfe for editorial criticisms. This represents a contribution from Nebraska Pittman-Rohertson Project W-33-R “Studies in the ecology and management of prairie grouse.” — Lawrence J. Blus, Nebraska Game, Forestation and Parks Commission, Thedford, Nebraska, 18 October 1966. Regurgitation by Killdeer as a possible means of dispersal for seeds and aquatic organisms. — Gleason and Cronquist (1964. “The Natural Geography of Plants.” Colum- bia Univ. Press, New York) suggest that transport via the external surfaces of waterhirds is the principal dispersal means for seeds of a(|uatic angiosperms. On the contrary, however, Schlichting (I960. Trans. Amer. Microscopical Soc., 79:160-166) has found that mud and debris seldom remain on ducks suspended in air for more than 30 minutes. Resistant disseminules may he carried between atjuatic habitats within the 449 450 THE WILSON BULLETIN December 1967 \’ol. 79, Pso. 4 intestinal tract of birds. Barriers to dispersal possibly exist, then, for aquatic organisms lacking resistance to avian digestive processes. A recent observation indicating that dispersal via the avian intestinal tract might be feasible for seeds and other aquatic organisms deficient in resistant disseminules prompted this note. In the course of an investigation to determine and contrast the effects of avian digestion on disseminules of 23 aquatic angiosperm species, Killdeer < Charadrius vociferus) and Mallards h Anas platyrhynchos) were fed various seeds. Occasionally Killdeer were observed to regurgitate portions of their meal within one hour after ingestion. The small pellets apparently had not entered the proventriculus for they were not altered by digestive processes. Viable seeds of the plant species under investiga- tion were discovered in each of the disgorged pellets. Regurgitation generally followed the feeding of large seeds or occurred when the birds gorged themselves. My observations of disgorgement by Mallards in the present study confirm an earlier report of this phenomenon by Malone (1966. Wilson Bull., 78:227-228). Disgorgement, however, has not previously been observed among waders. Little significance can be attached to this observation with respect to dispersal of aquatic plants since a majority of the species surveyed possess resistant seeds which survive passage through the avian intestinal tract. However, seeds < notably of upland plants) which failed to pass successfully through Killdeer remained viable after disgorge- ment. Seeds of Ratibida columnifera, Samolus parviflorus. Cosmos bipinnatus, and Raphanus raphanistrum each failed to pass successfully through the Killdeer intestinal tract, but were viable after regurgitation. Other aquatic organisms or their disseminules ingested by Killdeer, yet not capable of withstanding avian digestive processes, may also be dispersed by this method. Transport via the crop of birds would be a highly advantageous means of overland transport for seeds of aquatic species, aquatic organisms, or other disseminules destroyed by avian digestion or by desiccation. Nevertheless, the occurrence and frequency of regurgitation are poorly documented. Further research is needed to elucidate this neglected mechanism of dissemination. — Victor L. de Vlaming, Department of Biology, Texas Technological College, Lubbock, Texas. (Present address: Department of Zoology, University of California, Berkeley, California) , 3 October 1966. Mourning Dove egg in nests of Catbird and Robin. — The Mourning Doves iZenai- dura macroura) occasionally utilize nests of other birds and squirrels as a platform for their own frail nest, and they often use old Mourning Dove nests again ( Hanson and Kossack, 1963. Illinois Dept, of Conserv. Tech. Bull. 2). In the spring and early summer of 1966, at Fremont, Nebraska, 1 observed the re-use of old nests several times. In addition, I observed one Mourning Dove egg placed in an old nest. This one egg was never incubated. On 6 May, a Robin (Turdus migratorius) nest had no eggs at 0555. At 0545 on 7 May, a Mourning Dove was sitting on one Robin egg and one dove egg. The Robin laid three more eggs but the dove was never seen at this nest site again. Three of four Robin eggs hatched but the dove egg was unhatched after 17 days. It was opened and appeared to have been infertile. On 30 May, a Mourning Dove was discovered incubating one egg in a Robin nest. She had added no nest material to the Robin nest. The egg hatched and the young bird was fledged on 16 June. Decenihcr 1067 Vol. 79, No. 1 GENERAL NOTES 451 On 5 and 6 June, a single Mourning Dove egg was laid in each of two different Catbird i Dumetella carolinensis) nests. These nests were approximately 200 meters apart and I suspect that the same dove laid both eggs. On 5 June, a dove had laid an egg in one of the Catbird nests just after it was completed. She had added a few twigs of her own to the nest. The dove egg remained in the nest until 8 June when there were two Catbird eggs. I suspect that the Catbird removed the dove egg. On 6 June, a dove egg was laid in a Catbird nest that had just been completed the previous day. It remained there for two days and then disappeared. Catliird eggs were not observed in this nest. It may he that the Mourning Doves that laid these eggs had eggs in the oviduct before they had constructed a nest and used the first convenient site they could find. These observations were made in connection with Red-winged Blackbird research supported in part by the Chapman Memorial Fund. I would like to thank James Linder, a student at Midland College, for bringing the one nest to my attention. — Larry C. Holcomb, Department of Biology, Creighton University, Omaha, Nebraska, 27 September 1966. Overlapping nestings by a pair of Barn Owls. — In February, 1961, a male Barn Owl {Tyto alba) was captured in a church spire in New Haven, Middlesex County, Con- necticut. It was banded and returned to the tower after four weeks in captivity. In April a Barn Owl was incubating seven eggs in a corner of the room over the tower belfry. Five young were reared from this clutch, fledging in mid-August, after which the family left the tower. In 1962 five eggs were laid between 8 and 17 April. Subsequent candling revealed that only three of these were fertile and only two hatched. Between 16 May, when I first saw the two young, and 4 July I made only brief visits. Usually both adults were seen (the male banded) but no attempt was made to capture them, as they invariably flew up inside the spire to perch on a small platform near the top. Light from a small glass window near the platform made them easily seen. On 4 July the older nestling displayed aggressively when I entered the tower. Both were running and jumping about, hut were not able to fly upward. The following day I returned to the tower, accompanied by Mr. Michael Trevor and Rev. Edward L. Duncan. The young were as aggressive as on the previous day, but were easily handled for banding. The only adult present, an unhanded bird which we assumed to he the female, did not fly up the spire but allowed itself to be captured rather easily. In contrast to the struggling, hissing young, this bird was docile when handled. When released, it flew to the perch inside the spire window and remained there. Despite my assurance that his attempts would prove futile, Trevor insisted on searching the tower for possible eggs. To my chagrin, he located a clutch of four warm eggs in a hollow of the wall, eight feet directly over the original nest site. After ascertaining that at least one egg contained an embryo, we left the tower. On II July we returned, finding only a handed adult present. Where the four eggs had been, there was now only the empty cavity. While there is no proof that the same female or even the same male owl was involved in the two 1962 nestings, there is less evidence that more than two birds were involved. 452 THE WILSON BULLETIN December 1967 \'ol. 79, No. 4 If three or four owls were occupying the tower concurrently one would have expected to find more than two birds present on at least some visits. Moreover, one might have expected a greater degree of overlap between the two broods if two pairs or two females were present. Stewart (1952. Auk, 69:227-245) notes that Barn Owls have been found breeding in all months of the year, even in the northern part of their range. He cites a case of a pair in New \ork with young in late July and again in December. In this case the female was banded and was recaptured with the second brood. Wayne (1908. Auk, 25:21-24) pointed out that in South Carolina the eggs are often laid in September. The only case of overlapping broods known to me is that reported by Morejohn ( 1955. Auk, 72:298) from California. The situation was similar to that in the Connecticut birds: the first brood had been reduced, by non-hatching and nestling mortality, to one bird. Of the four eggs in the second clutch, one was opened by Morejohn and found to contain an embryo, and two of the remaining three hatched. The above data suggest that in some parts of the United States individual Barn Owls are in breeding condition in all months of the year and that a pair may retain its breed- ing capability for a period longer than that found in most other large raptors. These characteristics facilitate the production of second broods, despite the four months required from egg laying to fledging in each brood. If the size of the first brood and the availability of food are such that one adult can provide food for both the young and the other adult, the second clutch may occasionally be laid before the first brood is out of the nest. — Peter L. Ames, Museum of Vertebrate Zoology, University of Cali- fornia, Berkeley, California, 27 July 1966. A possible case of egg transport by a Chuck-will’s-widow. — Audubon ( 1821. Orni- thological Biography, I.) reported observing oral egg transport in the Chuck-will's-widow iCaprimulgus carolinensis) . Although Audubon’s account for the Chuck-will’s-widow remains unconfirmed, Truslow (1966. Xatl. Geographic, 130:882-884) has observed and photographed similar behavior in a Pileated Woodpecker ^Dryocopus pileatus) . Ganier (1964. Wilson Bull., 76:19-27) dismissed Audubon’s account as a fabrication, or possibly a ghostwriter’s attempt to inject "novelty” into his writings. Ganier con- cluded that the lack of substantiating evidence for Audubon’s observations was sufficient to refute the story and stated that “future authors should avoid its repetition.” In the late spring of 1966, I witnessed a sequence of events suggesting that efforts to discredit egg transport in Chuck-wilPs- widows may be premature. Unfortunately, I attributed no special significance to the observations (until I read Truslow's paper), and consequently, I failed to record dates and other pertinent details desirable in a published account. My home near State College, Mississippi is adjacent to an 18-acre woods — pre- dominantly pine with a mixture of young deciduous growth in the understory. A number of cleared paths traverse the woods and I walk them almost daily. In 1965, a Chuck- will’s-widow nested near one path. On several occasions the female feigned injury by performing various antics in the path. No nest was observed. In 1966 (about mid-May), I flushed a Chuck-will’s-widow from a nest near the same area. The unprepared nest was 15 to 20 feet off the path on the forest floor which was matted with pine needles and deciduous leaves. I did not touch the two eggs. The next day, the female flew off the nest as I approached, but she remained on the nest when I walked by the following day. On the third day, I took my 5-year-old son to see the nest. When the female was not visible from the path, we approached the nest I December 1967 Vol. 79, No. 4 GENERAL NOTES 453 and found no young, eggs, or eggshells. I suspected that the young had hatched and moved away a short distance, or that a predator had devoured or removed the eggs. As we stood at the nest, my dog flushed a female from a site about 15 feet farther off the path. This nest also contained two eggs, and was similarly located, but partially concealed from the path by a small tangle of vines. The terrain between the nests was level, but leaves, pine needles, sticks, and debris would have made rolling the eggs a difficult task. Although it is possible that there were originally two nests, one of which was destroyed, it seems unlikely that nests would be located only 15 feet apart. Furthermore, only one female was observed and only a single male called in the 18-acre woods during the spring and summer of 1966. I related this incident to several persons at the time and expressed an opinion that the eggs had been moved by some means. The coincidence between my observations and those of Audubon is remarkable, to the extent that his statement provides a logical explanation for my own observations. At any rate, this incident justifies keeping the subject of egg transport in Chuck-will’s-widows open to investigation. — Denzel E. Ferguson, Zoology Department, Mississippi State University, State College, Mississippi 39762, 9 January 1967. Nest site movements of a Poor-will. — On 2 August 1965 the nest of a Poor-will iPha- laenoptilus nuttallii) was found in Little Valley, Nevada at an altitude of 7,300 feet. Little Valley is 25 miles south of Reno in the Carson Range. The nest, which was in a slight depression in pine needles and which contained two eggs, was on an east- facing slope. The dominant tree of the area is Jeffrey pine ( Pinus jeffreyi) , and the most common shrub of the immediate nest area is manzanita ( Arctostaphylos patula) . In the course of taking daily weights of the Poor-wills I found that the nest site was frequently shifted. On 7 August the parent bird flushed, exposing the young, 14 feet west of the original site. On 8 August the young were found 20 feet north of site number two. The nest site was in the same place on 9 August but on 10 August the nestlings were found 35 feet west of site number three. On 11 August they were found 17 feet south of site number four. Because of inclement weather the nest area was not checked on 12 and 13 August, but on 14 August the nest was found 7 feet west of site number five. The bad weather persisted through 15, 16, and 17 August, and on 18 August the young birds could not be found. This study was carried out at the University of Nevada Field Station in Little Valley. — Raymond N. Evans, Biology Department, University of Nevada, Reno, Nevada, 31 October 1966. The amphirhinal condition in the Passeriformes. — The occurrence of the amphi- rhinal condition has largely been ignored by ornithologists. Many of the early avian anatomists mentioned it briefly, usually in reference to the suboscines. For example, Forbes (1881. Proc. Zool. Soc. London, 1881:435-438) stated that in Conopophaga the external nares are divided into an anterior and posterior opening by the ossification of the alinasal cartilages, but he placed little taxonomic importance on the character because of its seemingly spasmodic occurrence in other families. Von Ihering (1915. Auk, 32:150) proposed that the term amphirhinal be used to apply to the “style of skull structure in which instead of one large bony nostril we have two, a posterior and anterior one . . . .” He was referring to the condition of the nostril found in the members of the Formicariidae that he had examined. Since that time very little work has been directed towards documenting the occurrence of this character or determining its functional significance. 454 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 OCCIJKKKNCK Table 1 OF THE AmFIIIKIIINAL CONDITION IN J’assehine Families No. forms examined No. am phirhinal Families Genera Species Genera Species Dendrocolaptidae 10 23 2 2 Furnariidae 29 48 1 1? Formicariidae 26 37 24 33 Conopophagidae 2 2 1 1 Cotingidae 14 24 8 11 Tyrannidae 73 129 21 30 Phytotomidae 1 2 1 2 Corvidae 17 39 2 2 Grallinidae 2 2 1 1 Timaliidae 7 11 1 1 Pycnonotidae 6 13 3 4 Chloropseidae 3 3 1 1 Vangidae 2 2 1 1 Laniidae 8 14 5 8 Prionopidae Ploceidae 2 2 2 2 Buhalornithinae 2 2 2 2 Passerinae 4 8 1 1 Ploceinae 3 17 1 7 Estrildinae 8 26 1 1 Thraupidae 27 69 1 1 While studying the Dendrocolaptidae and Furnariidae I was surprised to find the amphirhinal condition present in the woodhewer Xiphorhynchus erythropygius, hut absent in the six other members of the genus that I examined, especially in view of the fact that the genus Xiphorhynchus las delimited by Peters, 1951. “Check-list of birds of the world.” Vol. VII. Cambridge, Harvard Univ. Press) is a rather uniform group with respect to other details of skull structure. In an attempt to learn the taxonomic distribution of this character I surveyed the passerine birds in the skeletal collection of the University of Michigan Museum of Zoology. In Table 1 are listed the families that I examined that contain amphirhinal members. The sequence of families follows that proposed by Wetmore (I960. Smithsonian Misc. Coll., 139). The following is a list of the families that I examined which contain no amphirhinal members. The first number in parentheses represents the number of genera examined, the second, the number of species. Rhinocryptidae (2,2), Pipridae (6,14), Alaudidae (6,9), Hirundinidae (10,21), Dicruridae (1,4), Oriolidae (1,5), Ptilonorhynchidae (1,1), Paradisaeidae (1,1), Paridae (4,17), Sittidae (2,6), Certhiidae (2,3), Chamaeidae 11,1), Campephagidae (2,4), Cinclidae (1,2), Troglodytidae (9,31), Mimidae (10,20), Turdidae (16,58), Sylviidae (18,34), Muscicapidae (15,19), Prunellidae (1,1), Motacillidae (3,14), Bombycillidae (1,3), Ptilogonatidae (3,4), Dulidae (1,1), Artamidae (1,1), Cyclarhidae (1,1), Sturnidae (6,12), Meliphagidae (6,8), Nectariniidae (2,12), Dicaeidae (1,1), December 1967 Vol. 79, No. 4 GENERAL NOTES 455 Zosteropidae (2,6), Vireonidae (2,17), “Coerebidae” (6,12), Parulidae (21,69), Plo- ceidae: Viduinae (3,4), Icteridae (18,42), Tersinidae (1,1), Fringillidae: Richmondeninae (12,24), Fringillinae (1,2), Carduelinae (14,36), Emberizinae (47,123). The oropendolas and caciques of the Icteridae and the Cracticidae are excluded, for in these massive-billed birds it is impossible at present to state whether or not the condition of the nostril was preceded by the amphirhinal condition. In many cases several specimens of each species were examined, in other cases only one specimen was available. I found that in some species the amphirhinal condition may be present in some specimens, but not in others. I was unable to determine if an age factor is involved, but I suspect it may be, because in certain specimens a partially formed bony plate is present in the nostril that would represent the amphirhinal condition if fully formed. In some specimens preparation of the skull may account for the apparent absence of the amphirhinal condition, especially in soft-billed species. For these reasons, it is likely that some families listed here as lacking the amphirhinal condition will be found subsequently to possess it in some species. Tlie apparent parallel evolution of the amphirhinal condition in diverse passerine families probably indicates a potential for producing the character in all passerines. In fact, all that is necessary is the ossification of a cartilage. Of interest in this respect is one specimen of the ovenbird PhUydor rufus which shows the nostril bounded by a membrane that has become partially ensheathed with bone; if ossification were com- pleted this would represent the amphirhinal condition. Both available specimens of PhUydor lichtensteini lack the condition. One specimen of the cotinga Gymnoderus foetidus shows no sign of the amphirhinal condition; in another specimen one side of the nostril has a condition very similar to that described above for the specimen of PhUydor rufus. The apparent ease with which the amphirhinal condition has arisen in so many passerine families, plus the fact of its occurrence in some species but not in others of reasonably well-defined genera is sufficient recommendation for extreme caution with its use, if any, in passerine taxonomy. Genera in which the amphirhinal condition is present in some species but not in others include Xiphorhynchus, Cyanolyca, Garrulax, Lanius, and Passer. Detailed analysis of foraging behavior and of the forces acting on the bill might give a clue as to the function of the amphirhinal condition. I am indebted to R. W. Storer and H. B. Tordoff for criticizing the manuscript, and to N. L. Ford and J. R. Jehl, Jr. for offering many helpful suggestions. — J. Alan Feduccia, The University of Michigan Museum of Zoology, Ann Arbor, Michigan, 27 September 1966. A Common Crackle learning to soak bread. — ^There is only a little information available on specialized feeding techniques learned by wild birds, and still less data on how these are acquired. This has prompted me to record the following observations made on a lawn in Chesterton, Indiana, in the spring of 1966. In April and May, 1966, when a half dozen pair of Common Crackles (Quiscalus quiscula) were feeding on our lawn, we put out bread and water and grackles came regularly to eat dry bread, and to drink. But, our desultory watching gave no record of “dunking.” Then on 15 May 1966, I noticed a female grackle with white marks acquired from the newly painted wall of a neighbor’s garage against which its nest was placed. The following itemized observations refer to this bird: 456 THE W ILSON BULLETIN December 1967 Vol. 79, No. 4 3:50 I’M White-marked female ate dry bread; flew to nest. 4:00 I’.M White-marked female came, ate dry bread, swallowing with difficulty, and went to water. As she bent to drink, several crumbs fell from gape into water, apparently accidentally. She drank, then picked two crumbs from water and swallowed them; then walked hack to bread, picked up a piece, walked hack to water, dropped it in, and ate the wet bread ; flew to nest. 4:10 I’M Female came, carried a piece of bread to water, dropped it in, and ate it; then flew on to nest. 4:30 I’M Female came, drank, walked over to bread, carried a piece to water, dropped it in, picked off pieces; after eating about one-half of piece, female flew back to nest. 5:00 I’M Female returned to food, ate part of dry bread hut too hard to manage and abandoned it; got another piece, ate it dry; walked to water, drank, flew to nest. There is no doubt what happened. The following interpretation is possible. The grackle was in the habit of feeding on dry bread and drinking. By accident it found dropping bread into the water made it easier to swallow. This association was utilized immediately, and was used in two following periods of feeding, about 10 and 20 minutes apart. At the next feeding period, 30 minutes later, the association had been lost. Some six or eight other grackles, males and females, came to feed on the bread and to drink during this same period and some were there while the white-marked female was “dunking” bread. At 4:35 three grackles found the bread left in the water by the white-spotted female at 4:30 and ate it greedily. But, no other bird dunked its bread. Can it be that the habit of dunking bread, a fairly common, but irregularly used one of grackles is a matter of learning by each individual? Tlie general habits of the birds would make the acquiring of such a specialized feeding technique an easy step. The sporadic use of the technique would support this view that each learns it. — A. L. Rand, Field Museum of Natural History, Chicago, Illinois, 29 September 1966. Prealternate molt in the Summer Taiiager. — One of the most useful qualities of the method of study of molts and plumages introduced in 1959 ( Humphrey and Parkes, Auk, 76:1-31) has proved to be its predictive value. It has been possible to find molts, previously unreported, whose presence in a sequence was deduced from sequences of related forms. For example, we have encountered, thus far, no bird species with two definitive (“adult”) plumages per cycle which does not also have two corresponding plumages in its first year. The discovery of the “missing” first alternate plumage of the Great Blue Heron i Ardea herodias) is described in our later paper ( 1%3. Auk, 80:500). Equally, we know of no species which has a prealternate molt in its first year of life, but never thereafter. A plumage sequence of this type has been alleged to occur in some genera of Icteridae (Cassidix, Molothrus) , but the limited prealternate molt of adults of these birds had simply been overlooked < A. R. Phillips and R. . Dickerman, MS.). Tlie seasonal change of plumages of males of the Scarlet Tanager iPiranga olivacea) is highly conspicuous, with a prealternate molt involving the exchange of greenish for bright red body feathers. Males of its close relative, the Summer Tanager ( P. rubra), however, never lose their pinkish red color once it has been attained at the first prealternate molt. Dwight (1900. Ann. Neiv York Acad. Sci., 13:223) described in detail the “partial prenuptial moult” (= first prealternate molt) whereby the greenish or yellowish “first winter” ( = first basic) plumage of Summer Tanager males is replaced by red feathers of the “first nuptial” (= first alternate) plumage. Dwight, however. December 1907 Vol. 79, No. 4 GENERAL NOTES 457 went on to say that the “adult nuptial plumage” is “acquired by wear which is not very perceptible even on close examination of the feathers. . . There appears to be no second prenuptial moult in this species.” This concept, of a prealternate molt confined to the first year, has been repeated without question in all of the subsequent literature of the Summer Tanager, culminating in the account by Bent (1958. U.S. Natl. Mus. Bull. 211:499-500), who quoted much of Dwight’s description verbatim more than half a century after its original publication. It is perhaps understandable that Dwight, in 1900, had insufficient material available to permit demonstration of the prealternate molt of adult Summer Tanagers. Oddly, no subsequent author seems to have bothered to check the now abundant material of this species taken on the wintering ground (chiefly South America), where the pre- alternate molt does, in fact, take place. The present note is based on a study of the eastern race, Piranga r. rubra, of which ample material was available to me, well distributed both geographically and seasonally. A similar study of the western P. r. cooperi would be more difficult, as the breeding and wintering ranges overlap, and the breeding season of the more southern populations in Mexico may be expected to be rather different from those in the southwestern United States. All specimens mentioned are in the collection of Carnegie Museum. Dwight (loc. cit.) properly emphasized the variability of the extent of the first prealternate molt, by which the male attains his first red feathers. This molt may involve all of the feathers except the primaries, or may be confined to isolated patches on the head, breast, mantle, upper tail coverts, etc. There is, of course, a fundamental misunderstanding involved in the statement by Burleigh ( 1958. “Georgia Birds,” Univ. of Oklahoma Press, p. 606) that “Occasionally an individual will be seen that has failed to acquire this adult plumage after the post-juvenal moult, and presents an odd appear- ance, the back and underparts being patched with rose-red and olive green.” Birds of this aspect are commonly, not “occasionally” seen (as quickly evident by a glance at any museum tray of Summer Tanagers), and the “adult plumage” is acquired at the second prebasic (“first postnuptial”) molt rather than “after the postjuvenal moult.” The patchy appearance of the first-year males seen in the United States in spring is misleading. Although (for example) the figure presented by Eaton (1914. New York State Mus. Mem. 12, pt. 2:pl. 87) is captioned “changing male,” active molting has ceased by the time most migrants have reached the southern United States, in late March or early April. Examination of a series of 38 first-year spring males failed to show any evidence of active molt in the form of sheathed feathers after the end of March. The peak period of molt is probably February to early March. A 27 February and a 17 March specimen, both from Colombia, are superficially similar in appearance with respect to relative amount of red present. The earlier bird, however, has many and the later bird few incoming feathers, suggesting that the February-taken bird would ultimately have become the redder of the two. The prealternate molt of adult males is naturally much less conspicuous than that of first-year males, simply because the incoming feathers are the same color as the surrounding old ones, which are normally relatively little faded or worn. Specimens examined suggest that the prealternate molt of adults is also highly variable in extent but probably never involves as many feathers as in the extreme cases among first-year birds. Dates of collection of eight molting adult males from Costa Rica, Colombia and Venezuela are as follows: 22 December, 12 January, 24 January, 3 February, 6 March, 11 March, 12 March, and 16 March. In none of these is there any sign of molting of flight feathers; pinfeathers are usually most easily demonstrated on the crown, but also 458 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 appear on back, throat, and breast. Even the earliest of these dates is far too late for the incoming feathers to represent the last of the prebasic molt, which takes place principally in August hut may begin as early as 15 July (specimen from Takoma, Mary- land) . Of female Summer Tanagers, Dwight (loc. cit.) states: “The plumages and moults correspond to those of the male, hut the plumage remains similar to that of the male in first winter and the first and only prenuptial moult is mostly suppressed. Adult females may he red tinged, l)ut regularly they are even yellower than the male in first winter dress.” Roberts ( 1932. “The Birds of Minnesota,” vol. 2, Univ. of Minnesota Press, p. 697) even goes so far as to state not only that the “prenuptial” molt of males is confined to the first year, hut that even this first-year molt is absent in females. First-year female Summer Tanagers may he recognized as such by their more pointed rectrices and brownish or grayish rather than greenish tertials. Examination of specimens reveals that, just as in males, both age classes of females undergo a prealternate molt on the wintering ground. Four adult females with sheathed incoming feathers were collected as follows: 20 January (Colombia), 23 January (Venezuela), 24 February (Venezuela), and 5 March (French Guiana). Molting first-year females were collected in Colombia on 22 January, 12 February, and 23 February, and in French Guiana on 26 January. The latter specimen is not only in heavy body molt, but is replacing rectrices. It and several other very reddish females show that Dwight was incorrect in believing that only “adult” females of this species are red tinged; reddish feathers may often be attained at the first prealternate molt. Those females with the most extensive prealternate molt are frequently those with the reddest, or most “masculine” plumage, suggesting a hormonal relationship between these two variables. In summary, in spite of long-repeated statements to the contrary, both first-year and adult birds of both sexes of the eastern subspecies of Summer Tanager (Piranga r. rubra) have a highly variable partial prealternate molt, taking place on the wintering ground between late December and late March. — Kenneth C. Parkes, Carnegie Museum, Pittsburgh, Pennsylvania, 29 September 1966. CORRECTION Vol. 79, page 342, line 19 should read, “. . . . Chuck-will’s-widow was a nearly intact male Cape May Warbler {Dendroica tigrina) . Only . . .” THE PRESIDENT’S PAGE As we reported in the September Bulletin, Roger Peterson found that the scheduling of a trip which he is committed to lead will make it impossible for him to attend the Carhondale, 111., meeting to be held during 2-5 May 1968. Thus, Dr. Peterson will be unable to serve as Chairman of the symposium on the preparation of state bird books, whose organization he was so enthusiastically planning. We shall miss him. Nevertheless, the symposium will go on as planned. And all of us will be delighted to know that an excellent man. Chandler S. Robbins, has agreed to serve as Chairman of this important feature of the Carhondale meeting. Mr. Robbins’ qualifications for this assignment need no elucidation among North American bird students. I will mention one point of particular relevance: the fact that Mr. Robbins is a co-author of the highly esteemed “Birds of Maryland and the District of Columbia.” While we have referred to the proposed discussion of state bird books as a “symposium,” I learned during a conversation with Mr. Robbins that it may not l)e such in the usual, formal sense. Rather, he may organize a panel discussion in which the participants will express their opinions on various aspects of state bird books which are of special interest both to the authors who write them and to the rest of us who read and use them. What this means is that, to a greater degree than is usually the case, all of us can contribute to the success of the symposium, or panel discussion, by suggesting to Mr. Robbins the particular aspects of state bird books which we should like to see discussed. What do you look for, in particular, in such a book? What should be the emphases of future books of a state, provincial, regional, or national nature? This is to urge, therefore, that, between now and next May, members send in suggested topics for discussion, about state bird books, to: Mr. Chandler S. Robbins, Migratory Bird Populations Station, Laurel, Maryland 20810. Here is a unique opportunity for each of us to make a contribution towards the success of an annual meeting of our Society. Aaron M. Bagg LOUIS AGASSIZ EUERTES 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. Recipients 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 additional money. The Council of the Wilson Ornithological Society has added funds as necessary to provide at least one $100 grant annually. Two grants were made in 1966 and again in 1967. Although grantees are not required to publish their studies in The Wilson 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 24 persons, many of whom have continued their research work. Application forms may he obtained from Harrison B. Tordoff, Museum of Zoology, The University of Michigan, Ann Arbor, Michigan 48104. Completed applications must l)e received by 1 March 1968. 459 ORNITHOLOGICAL NEWS On 15 Septeml)er Roger T. Peterson, the immediate Past President of the WOS, was awarded the first Arthur A. Allen Award hy Cornell University for distinguished service to ornithology. First Vice-President H. Lewis Batts was honored with an American Motors Company- Conservation Award for his efforts in establishing the Kalamazoo Nature Center. The Kalamazoo Nature Center won one of the four merit awards given in 1967 hy the Soil Conservation Society of America. Ceorge M. Sutton was one of eight persons honored hy induction into the Oklahoma Hall of Fame on the occasion of the state’s 60th birthday on 16 November 1967. The International Council for Bird Preservation has announced that the Pan-American Section of the Council will meet during the week of 18-24 March 1968 in Caracas, Venezuela. Details about the meeting can he obtained from: Comision Organizadora, Reunion PANAM-CIPO ’68, Sociedad Venezolana de Ciencias Naturales, Apartado 1521, Caracas, Venezuela. The classic ornithological spoof, ‘‘Eodrnis pterovelox gohiensis” by A. C. Fotheringham is once again available for $1.10 post paid in the U.S. and Canada and $1.25 elsewhere from G. E. Watson, 2621 0 Street N.W., Washington, D.C. or R. C. Banks, 3200 Curtis Drive, Washington, D.C. 20031. The Eastern Bird Banding Association is again sponsoring a $100 award for student research (graduate or undergraduate) in ornithology that includes bird banding as a part of the research. Applications must he received prior to 29 February 1968. Details are available from F. R. Scott, 115 Kennondale Road, Richmond, Virginia. It is a pleasure to announce the addition of Dr. Glen E. Woolfenden of the University of South Florida, Tampa, as a new member of the Editorial Board of the Bulletin. Tlie preparation of a volume of a journal such as The Wilson Bulletin is a cooperative effort on the part of many people and the Editor wishes to express his thanks at this time to all those who participated in the production of Volume 79. Besides the authors of the papers and reviews (approximately 100 in number), 21 ornithologists reviewed papers and offered comments or criticisms. The members of the Editorial Board, whose names appear on the hack cover, in addition to reviewing papers served as never-failing sources of information for the Editor. President Aaron Bagg, and Past Secretary P. B. Hofslund contributed help in a variety of ways. Once again the tedious job of preparing the index was carried out by Miss Mildred Stewart. I would like also to add a word of thanks to the many members who took time out to send me comments about the Bulletin. These have been very helpful, and while it has not been possible to answer each of these personally they nevertheless have been greatly appreciated. — G. A. H. 460 ANNUAL REPORT OF THE CONSERVATION COMMITTEE President Aaron M. Bagg’s address at the Crawford Notch meeting stressed the responsibility of ornithologists in the defense of our common environment and was good orientation for the report of the Conservation Committee. As Mr. Bagg said, “what we do to the environment we do to man himself.” This statement is part of a new wave of awareness that the scientist must accept some responsibility for the use of his data, as so well expounded by Dr. Barry Commoner in a small but important book, “Science and Survival,” published in 1967 as an outgrowth of the deliberations of the American Association for the Advancement of Science’s committee on the role of science in human affairs. The Wilson Ornithological Society’s role should, and can be an expanding one in informing citizens and legislators and other groups of the need for studying the interrelationships of living things and their environ- ment and the implications of applying our technology to the out-of-doors. One attempt to make the voice of science effective, in this case through the judicial process, is the legal action brought by Victor J. Yannacone, Jr., to bar the use of DDT by the Suffolk County (Long Island, N.Y.) Mosquito Control Commission, because the use of so long-lived an insecticide leads to poisoning ecosystems and depleting popula- tions, particularly those at the ends of long food chains. A temporary injunction granted on 15 August 1966, has continued in force, a one week trial presented the pros and cons of the scientific evidence, and the court has withheld judgment on the constitutional issue raised although it agreed that the use of DDT should be barred because of its effects in the environment. The National Audubon Society has published the transcripts of this hearing, together with pleas, etc., and copies of this 400-page volume are available for $15.00 each from the Society’s New York office. The Torrey Canyon disaster off the southwest coast of England that loosed 118,000 tons of crude oil in the Atlantic Ocean and the English Channel in March was the most dramatic conservation challenge of the year. Sweeping across the Channel, the oil pollution killed 90 per cent of the nesting alcids of the Brittany Coast in Erance, and no estimate of the loss of British sea birds was possible. Of some 7,000 birds rescued and put through a cleaning process by volunteers in England, less than 500 survived. A great and continuing out-pouring of suggestions for coping with such disasters, whether by detergents or jelling substances, or otherwise, overlooked the fact that present regula- tions lack teeth and the imposition of fines high enough to induce adequate care to prevent a repetition of such blundering, or perhaps even halt the trend to larger and larger tankers which makes accidents increasingly difficult to cope with. Mr. James Baird of the Massachusetts Audubon Society pointed out that a challenge of perhaps similar proportions faced the United States in connection with recent requests for permits to exploit the oil-bearing strata underlying George’s Bank off Cape Cod, Mass., where 70 per cent of our fish food supplies come from. The back-up approach to Whooping Crane conservation got off to a good start this spring. U.S. and Canadian wildlife biologists found eight occupied nests in the Wood Buffalo Park area, took six eggs by a quick descent from helicopters, and flew the eggs in specially designed, heated carrying boxes to the Patuxent Wildlife Research Center, Maryland. One egg hatched en route and the chick died. Another young died shortly afterward, but five young birds now form the nucleus of a new captive flock. Of equal importance, surely, is the return of all parent birds to their nests after having l)een robbed of that one egg of their double clutch which they were unlikely to fledge in any rate. Disturbance thus appears to have been minimal (see editorial of The Threatened Species Program, Audubon Mag., May-June, 1967). 461 462 THE WILSO'N BULLETIN December 1967 Vol. 79, No. 4 In April the Ohio Farm Bureau succeeded in getting the agricultural estahlishment to call a North American Conference on Blackbird Depredation at Columbus. The drive for agricultural efficiency (measured solely in return on dollar invested) is obviously in conflict with birds that are attracted to feedlots and crops grown in the wrong place, and certain of the more aggressive farmers are impatient with the conservative approach of the U.S. Fish and Wildlife Service in providing “control” and would like to see this operation shifted to the U.S. Department of Agriculture. This demand, to suit the convenience of individual producers, is part of that federal-private combination economist Galbraith calls the technostructure and is thus subject to the serious scientific shortcom- ings Professor Commoner warns about. The Congress, fortunately, moderated the dispute by appropriating $800,000 for a program centering on the estahlishment of a field research station in Ohio. As this report went to press, however, at least one Congressman was attacking the appropriation as an unnecessary luxury in view of impending tax increases proposed to counterbalance the Vietnam W ar outputs. Whether or not the research station is built, ornithologists had better keep a wary eye on the control establishment. In March the National Audubon Society spearheaded a civil suit against the U.S. Army Corps of Engineers to prevent the “pulling of the plug,” in Canal 111 where this crosses U.S. Route 1 below Homestead, east of Everglades National Park. It was insisted that this section of Route 1 should not he excavated until suitable barriers have been built in the canal to prevent salt water intrusion into the Park. In May it was learned that the Corps of Engineers had directed its Jacksonville office to provide Everglades National Park with fresh water on “a basis parallel to the require- ments of municipalities, industry and agriculture.” No copies of the directive were provided other agencies or conservation organizations, but if the above paraphrase is at all accurate, the Park has to all intents been assured an equal diminishing share of the water it needs to keep it viable. What must be done is to give the Park priority until its minimum needs have been met. In southwest Florida, the National Audubon Society had to purchase nearly four sections of wetlands, at a price of $650,000, to protect its famous Corkscrew Swamp Sanctuary against drainage by land speculators; and in Texas, conservationists, led by Congressman Bob Eckhardt of Houston, opposed the granting of permits to dredge the oyster reefs of Galveston and Trinity Bays. Legislation < H.R. 25 introduced by Congress- man John Dingell) to prevent wasteful dredging of estuaries was compromised in early July when the Army Corps of Engineers and the Department of the Interior entered into a Memorandum of Understanding which would give Interior the privilege of review- ing all applications for dredging permits in estuarine waters. Conservationists imme- diately pressed Secretary UdalPs office with examples of projects needing review, and the Bureau of Sport Fisheries and Wildlife made the Galveston Bay problem its first test case. Of growing concern to many of us is the burgeoning trade in imported wild species for the pet trade. Hummingbirds from South America bring $50 and up in a Denver pet shop, and hordes of individuals of scores if not hundreds of species seem available to anyone willing to pay the price. This is commercial exploitation that rivals the plume trade of the turn of the century. California, a principal port of entry, is reviewing its laws and regulations, and it is hoped that this review may give the nation a new' perspec- tive on a problem created by the advent of inexpensive air freight. WOS Conservation Committee Roland C. Clement, Chairman, Wm. H. Drury, Jr., Richard L. Plunkett ORNITHOLOGICAL LITERATURE The Birds of Canada. By W. Earl Godfrey. National Museum of Canada Bulletin No. 203, Biological Series No. 73, Ottawa, 1966: 8Y2 X H in., 428 pp., 69 col. pis. by John A. Crosby, many line drawings by Stewart D. MacDonald, 2 endpaper maps, 380 small distributional maps. $12.50. (Checks should be made out to the Receiver General of Canada and order mailed to the Queen’s Printer, Ottawa.) Many of the most exciting days of my life have been lived in Canada. Icebergs, seals, fulmar petrels, and shearwaters “down north” along the Labrador; treacherous “white water,” with long portages to match, along the Abitibi and the Missinaibi; vast mudflats and a skyful of wavies at the south end of James Bay; Eskimos, husky dogs, walruses, and polar bears on Southampton Island; clouds of mosquitoes and brown muskeg water at Churchill; Black Oystercatchers and a dripping jungle of salal at the north end of Vancouver Island; Clark’s Nutcrackers, mountain goats, and hoary marmots in high country near Red Pass, British Columbia; ocean whirlpools in Richmond Gulf and Frobisher Bay; bands of caribou at Amadjuak; cliffs towering above the ocean ice along the north coast of Victoria Island; Solitary Sandpiper eggs in a waxwing nest near Rocky Mountain House, Alberta; recently hatched Knots on Jenny Lind Island; Ross’s Geese circling over their nests in the Perry River district south of Queen Maud Gulf — all these have been part of my experience during the past fifty years. Memories of them are vivid and important. Small wonder that I open so eagerly this new “Birds of Canada” with its eye-catching jacket photograph of an Arctic Tern. The picture itself rouses memories — of a newly hatched baby tern crouched on the sand, of an irate parent directly above me, and of blood enough on my forehead to convince me that I was not wanted there. Except for the somewhat surprising omission of habitat photographs, Earl Godfrey’s book is no disappointment. Most of the 518 species covered are exceptionally well illustrated in color. Three forms considered full species in the A. 0. U. Check-list of North American Birds (1957) — the Blue Goose, Black Brant, and Harlan’s Hawk — are believed by Godfrey to be conspecific with the Snow Goose, Brant, and Red-tailed Hawk, respectively; one form, Thayer’s Gull, which the Check-list considers a race of Herring Gull, Godfrey believes to be a full species. For each of 380 species there is a good map showing breeding distribution in red. Species writeups, each with measurements and a discussion of field marks, habitat, nesting, over-all range, range in Canada, and subspecies found in Canada, cover the ground effectively. Maps prepared by the Surveys and Mapping Branch of the Department of Mines and Technical Surveys in Ottawa serve as endpapers. The map at the front gives the position of hundreds of localities — though I look in vain for Killinek and Indian Harbor on the Labrador, for Masset on the Queen Charlotte Islands, and for Taylor Island, off the eastern end of Victoria Island, place- names which are important ornithologically. The map at the back shows the distribution of forest regions, grassland, and tundra. The treeline merits careful study. The fact that forest extends northward to the mouth of the Mackenzie has long been known and documented; but the “fingers” of forest extending almost to the Arctic Ocean along the Anderson and Coppermine rivers, the “island” of forest along the Thelon River, and the straight, southwestward-pointing “finger” of forest along the Leaf River, between the head of Ungava Bay and the east coast of Hudson Bay, have received comparatively 463 464 THE WILSON BULLETIN December 1%7 Vol. 79, No. 4 little attention in ornithological literature. Maps giving in detail the breeding distribution of such hardy woodland species as the Boreal Chickadee. Ruby-crowned Kinglet, and Pine Grosbeak probably would show some or all of these "fingers" and "islands." The parts of the hook headed "Range in Canada" must have involved a staggeringly large amount of work. I have not gone over much of this material in detail, for checking many records would be impossible without visiting the National Museum of Canada, where "the source of any particular distributional or other data" is available < p. 7 » ; but the records for certain species in which I have long had special interest ” with the problems of artificial arrangements, pieces of branches, patches of forest, etc. The simple profiles are not monotonous because they are profiles of living birds. The way in which water, dead leaves, and hits of debris have been “whisked in” is, in my opinion, remarkable. The engravers and printers deserve much credit for their part in producing these fine plates. I call attention particularly to the Yellow-breasted Chat on Plate 59. Here the yellow of the breast is perceptibly richer in tone than that of the yellowest parts of the other warblers shown in the same plate. The color is precisely as it should he; what is noteworthy is that artist, engraver, and printer have so successfully collaborated as to do this beautiful l)ird full justice. Crosby will not resent my calling attention to certain shortcomings. Heavy birds such as the Band-tailed Pigeon in Plate 37 should not be shown at the very tip of a twig so slender that it would sag, thus forcing the bird to flutter in maintaining a foothold. Woodpecker feet should he drawn with great care, for the functional beauty of the powerful toes is something no artist should miss. In four-toed woodpeckers the hallux (first toe) is, according to my observations, invariably the shortest; the inner is some- what the shorter of the two front toes; and the outer of the hind toes is about as long as, hut never shorter than, the outer front toe. In Crosby’s adult male Yellow-bellied Sapsucker (6a in Plate 42) the hallux is far too long and the outer hind toe far too short; in the Red-bellied Woodpecker on the same plate the inner front toe is much too long and the outer hind toe much too short. In the Horned Lark and Skylark ( Plate 50) the hind claws should he only slightly curved. Straightness of the long hind claw is a dependable family character throughout the Alaudidae. Stewart I). MacDonald’s drawings add pleasing variety. Values in the two meadow- lark heads (Fig. 67) are not consistent. We read as yellow the dark tone of the chin and throat, yet the same dark tone, as used on the top of the head, is restricted not to the yellow forepart of the superciliary, as it should he, hut to brown parts of the crown and auriculars. In all adult Poniarine Jaegers that I have handled, the two middle rectrices “twist” in opposite directions in such a way as to give the tips of the feathers a “roofed” arrangement (Fig. 52). In both the Brown Creeper (Fig. 63) and Bobolink (Fig. 66) the tail has twelve rectrices rather than ten. The line drawings showing the modification of the sternum in the Whistling and Trumpeter swans (Figs. 17 and 18), the drawings of the foot of the Ruffed Grouse in winter and in summer (Fig. 43), and the drawing of the outermost primary in the Whimbrel and the Eskimo Curlew (Fig. 49) strike me as being especially well done. — George Mikscii Sutton. The Birds of Guyana (formerly British Guiana): A Check List of 720 Species, with Brief Descriptions, Voice and Distribution, By Dorothy E. Snyder. Peabody Museum, Salem, Massachusetts, 1966: 5% X 7% in., 308 pp., endpaper map. $6.00. The main value of this small hook is that it gives a complete list of the birds of Guyana. This was long overdue as nothing of the kind has been published since Charles Chubb’s monumental two-volume work, “The Birds of British Guiana” ( London, December 1967 Vol. 79, No. 1 ORNITHOLOGICAL LITERATURE 467 1916, 1921 ) . The records seem to have been compiled carefully and critically and are based mostly on specimens, though this is not always quite clear. We should have liked more definite data — e.g., on the ibises of the genera Theresticus, Cercibis, and Phimosus, as there has been some confusion in their identification by some authors. The lack of regular field observations is apparent in the case of many waders. The records certainly do not give a true picture of the actual situation. The short descriptions will be valuable in identifying the more “easy” species, hut those of certain flycatchers and anthirds, to mention only a few, will hardly help the field observer. However, we cannot blame the author for this because even the experts with specimens before them make sometimes contradictory identifications. There is also a special section on “voice” which will he especially useful for the English-speaking readers of the book. For this reviewer who “hears in Dutch” it was once more evident that the method of rendering bird songs and calls in words or phonetics is impractical. I tried all the songs and calls of the species with which I am familiar, hut I failed to recognize practically all of them as presented in the hook. I fear that it will be even worse for readers who speak the Latin languages. The bibliography at the end of the book contains a number of publications scarcely relevant to the subject. One would have wished for a complete bibliography of the ornithology of Guyana. For such a small book without illustrations, its price is high. — F. Havehschmidt. Birds in Our Lives. Edited by Alfred Stefferud. U. S. Department of Interior, Bureau of Sport Fisheries and Wildlife, Washington, D. C. 1966: 8 X H in., xiii -j- 561 pp., 1 col. pi. and 80 wash drawings by Boh Hines, 372 photos. $9.00 ( for sale by the Superintendent of Documents, Washington, D. C.). This elaborate hook is the second effort of the Bureau of Sport Fisheries and Wildlife to make available for the general public a semi-technical publication on North American wildlife, the first having been the 1964 publication, “Waterfowl for Tomorrow.” Many readers will recognize the ancestry of the present volume in the popular “Yearbooks of Agriculture” sponsored over the years by the Department of Agriculture. The general format as well as the method of presentation of the subject matter are very similar, and it comes as no surprise to learn that Editor Stefferud had also served as editor of the Yearbooks. Following a foreword by Secretary of the Interior, Stewart Udall, and an editor’s preface, the main portion of the hook eonsists of 54 chapters divided under nine topical headings: In Perspective, Literature and Arts, Sports and Recreation, In Nature’s Scheme, Seience and Husbandry, The Hand of Man, For Better or Worse, Answers to Conflicts, and For Their Survival. A total of 61 authors contributed to the work and a listing of their names reads like a Who’s Who in modern ornithology, conservation, and wildlife management. There is hardly a subject that even lightly touches on birds that is not included. The reader is treated to a wide gamut of interesting reading on such things as the use of birds on postage stamps and coins, as well as other artistic representations; the references to birds in the Bible and other literature; aspects of aviculture; falconry, waterfowl hunting, and such bird-watching sports as Christmas Counts, as well as such fundamental topics as bird biology, ecology, conservation, and management. The level of presentation is directed towards the general reader who may wish to learn something about birds. If he is not floored by the encyclopedic nature of the hook this reader 468 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 can learn an awful lot from this hook. It would seem to have attained its general purpose very well, hut one does wonder how many of those for whom the hook was intended will accept the offering. There is some unevenness about the various chapters, and while most of them deal adequately with their topics a few seem hardly worth including. To my mind the most effective chapters are the three introductory ones: ”\^hat Are Birds For?” hy Roger Tory Peterson; "Masters of the Air” hy Olin Sewall Pettingill, Jr.; and ‘‘Birds and Science” hy Ernst Mayr. The chapters on conservation by Roland Clement and John .\ldrich are also effective. As might he e.xpected most of the chapters on management are devoted to some of the specific problems with which the sponsoring Bureau is currently concerned, some of which are only of transitory or minor importance. I have two major criticisms of the hook. Despite the many chapters on conservation I do not feel that the hook gives a balanced ecological picture. While the pesticide problem (Avhich is probably temporary ) and such things as the casualties at TV towers reckenridge, W'. J., review hy, 127-128 474 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Brewer, Richard, Bird i)opulations of l)ogs, 371-396 Broadhill, Banded, 145, 152 Black-and-red, 152 (ireen, 145 Brockway, Barbara F., The influence of vocal behavior on the performer’s testicular activity in Budgerigars ( Melopsittacus undulatus ) , 328-334 Brooks, Maurice, The Appalachians, re- viewed, 123-124 Brooks, William S., Food and feeding habits of autumn migrant shorehirds at a small midwestern pond, 307-315 Brotogeris versicolorus, 276, 280 Brush, Alan H., Additional observations on the structure of unusual feather tips, 322-327 Brush-Finch, Chestnut-capped, 184 Bruun. Bertel, see Robbins, Chandler S. and Bubo virginianus, 39, 159 Bubiilcus ibis, 174, 181, 236, 245 Bucephala albeola, 38 Budgerigar, 328-334 Bufflehead, 38 Bulbul, Ashy, 152 Black-and-white, 152 Black-crested Yellow, 152 Black-headed, 152 Crested Brown, 145 Crested Olive, 152 Finsch’s, 152 Grey-bellied, 152 Hairy-hacked, 139, 152 Lesser Brown, 152 Red-eyed Brown, 139, 145, 152 Scaly-breasted, 137, 145, 146, 152 Scrub, 145, 152 Streaked, 139, 152 Stripe-throated, 152 White-eyed Brown, 145, 152 White-throated, 139, 145, 152 Bunting, Crested, 24 Indigo, 41, 102, 264, 267, 270 Lark, 24 Painted, 347 Rustic, 24 Snow, 23 Busarellus nigricollis, 275 Buteo albonotatus, 174, 181 brachyurus, 174, 181 jamaicensis, 38, 54 I a go pus, 54 lineal us, 38 magnirostris, 173, 275 nitidus, 173 platypterus, 38, 54, 405 Buteogallus anthracinus, 174, 175 urubitinga, 275 Butorides striatus, 275 virescens, 174, 180, 245 Cacicus cela, 277, 280 Cacique, Yellow-l)illed, 178 Calamospiza melanocorys, 24 Caldwell, Larry D., Attack behavior of a Loggerhead Shrike, 116-117 Calorhamphus fuliginosus, 152 Calyptomena viridis, 145 Campephilus principalis, 159 Camptostoma imberbe, 174 Campylopterus curvipennis, 170, 173 c. excellens, 179 hemileucurus, 172 Campylorhynchus, 196 zonatus, 173 Canary, 104, 106, 107 Canvasback, 38, 220, 239 Capella gallinago, 39, 307 Capita, 281 Caprimulgus carolinensis, 342, 452 vociferus, 375 Cardinal, 41, 264, 271, 294, 298, 299, 375, 377, 379, 383, 393 Carduelis carduelis, 91 Carleton, Geoffrey, review by, 355 Carlquist, Sherwin, Island Life: a natural history of the islands of the world, reviewed by Robert I. Bowman, 356 Carpodacus mexicanus, 94 purpureus, 41, 384 Carter, William A., Ecology of the nesting birds of the McCurtain Game Preserve, Oklahoma, 259-272 Caryothraustes poliogaster, 173 Casmerodius albus, 174, 236, 245, 275, 278 Cassidix major, 195 mexicanus, 173, 195 Dereniher 1967 Vol. 79, No. 4 INDEX TO VOLUME 79 475 Catbird, 39, 103, 294, 298, 299, 375, 376, 377, 379, 380, 383, 451 Cathartes aura, 174, 275 melambrotiis, 275 Catharus mexicanus, 172 Catoptrophorus semipalmatiis, 340 Celeus castaneus, 172 Centurus aurifrons, 75, 173 pucherani, 173 Certhia jamiliaris, 382 Ceryle torquata, 175, 276, 278 Chaetura vauxi, 174, 175 Chaffinch, 53, 57, 94, 104, 105, 106, 107 Chalcites maculatus, 152 xanthorhynchus, 152 Chamaethlypis poHocephala, 173 Chapman, Frank L., see Ogden, John C. and Chappell, Janet S. and Robert W. Ficken, Feeding reactions of Myrtle Warblers toward wax-moth larvae dyed various colors, 119 Charadrius collaris, 175, 275 semipalmatus, 314 vociferus, 39, 314, 450 wilsonia, 175 Chat, Yellow-breasted, 40, 118, 264 Chelidoptera tenebrosa, 276 Chen hyperborea, 38 Chickadee, Black-capped, 200-207, 374, 375, 377, 378, 380, 382, 392, 393 Boreal, 204, 205 Carolina, 264, 267, 270, 319-321 Chestnut-sided, 200-207 Oregon, 200 Chloris chloris, 104, 436 Chloroceryle aenea, 175 amazona, 175, 276, 278 americana, 175, 276, 278 Chlorophonia, Blue-crowned, 178 Chlorophonia cyanea, 277 occipitalis, 173, 178 Chloropsis cochinchinensis, 152 cyanopogon, 152 sonnerati, 152 Chlorospingus ophthalmicus, 173 o. wetmorei, 179 Chlorostilbon canivetii, 173 Chondrohierax uncinatus, 172, 181 Chordeiles acutipennis, 174 minor, 343 Chrysocolaptes validus, 152 Chuck-will’s widow, 264, 270, 276, 342, 452-453, 458 Chura, Nicholas J. and Paul A. Stewart, Care, food consumption, and behavior of Bald Eagles used in DDT tests, 441-448 Ciccaba virgata, 172 Ciconia ciconia, 54, 316, 317 maltha, 316-318 Circus cyaneus, 38, 54, 222, 382 Cissopis levariana. 111, 281 Cistothorus platensis, 39 Clangula hyemalis, 239 Cl ar avis pretiosa, 173 Clement, Roland C., Annual report of Conservation Committee, 461-462 Coccothraustes coccothraustes, 105 Coccyzus americanus, 174, 183 minor, 173, 183 Cochlearius cochlearius, 174 Coereba flaveola, 173, 277, 280, 293, 294 Colaptes auratus, 5, 7, 8, 10, 13, 14, 15, 16, 17, 18, 19, 20, 78, 382 «. cafer, 5, 7, 13, 14, 16, 17, 19 a. chrysocaulosus, 5, 10, 11, 13, 14, 15, 18, 19, 20 a. chrysoides, 5, 11, 13, 14, 17, 18, 19, 20 a. mexicanoides, 5, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 a. pinicolus, 5, 9, 18 cafer, 78 c. mexicanoides, 236 (Nesoceleus) fernandinae, 5 Colibri thalassinus, 172, 183, 236 Colinus virginianus, 174 Collins, Henry Hill, Jr. and Ned R. Boya- jian. Familiar garden birds of Amer- ica, reviewed, 127-128 Colonia colonus, 211 Columba flavirostris, 173 nigrirostris, 172 speciosa, 172, 182 Columbigallina minuta, 173 passerina, 174, 182 talpacoti, 173, 276 476 THE WILSON BULLETIN December 1967 \ ol. 79, No. 4 Contopiis cinereus, 173 virens, 382 Comiropsis carolinensis, 158 Coot, American, 39, 221, 341 Copsychus malabaricus, 153 Cociuette, Black-crested, 183 Coracina jimhriata, 152 Coragyps atratus, 174, 175, 275 Cormorant, Olivaceous, 180 Corrections, 350, 458 Corvus brachyrhynchos, 113, 114, 382 corax, 157, 160 cor one, 113 monedula, 113 ossijragus, 161 Cotinga, Lovely, 183 Cotingu, 277 amabilis, 173, 183 cay ana, 281 maynana, 281 Coutlee, Ellen L., Agonistic behavior in the American Goldfinch, 89-109 Cowbird, Bronzed, 175 Brown-headed, 41, 118, 371, 373, 374, 375, 377, 383, 385, 435 Cracraft, Joel, Comparative foraging behav- ior of Myiozetetes similis and Myio- zetetes granadensis in Costa Rica, 115-116 Crake, Uniform, 182 Crane, Sandhill, 157 Whooping, 155, 157 Crax rubra, 172 Creeper, Brown, 382, 385, 392 Criniger bres, 152 tinschi, 152 phaeocephalus, 152 Crocethia alba, 314 Crotophaga ani, 276 major, 276 sulcirostris, 173 Crow, Common, 113-114, 264, 267, 270, 271, 382 Fish, 161 Crypturellus boucardi, 172 cinnamomeus, 174 soui, 172 Cuckoo, Emerald, 152 Mangrove, 183 Scaled, 322, 324 Violet, 152 Yellow-hilled, 183, 264 Culicicapa ceylonensis, 152 Curlew, Long-hilled, 158, 340-341 (^yanerpes cyaneus, 173, 178, 184 Cyanocitta cristata, 39, 346, 382 Cyanocompsa cyanoides, 173 parellina, 174 Cyanocorax violaceus, 277, 281 yncas, 172 Cyanolyca, 455 Cyclarhis gujanensis, 173 Cyrtonyx ocellatus, 236 Uacnis, Scarlet-thighed, 119 Dacnis cayana, 277, 280, 281 lineata, 277, 281 venusta, 119 Daptrius americanus, 275 a ter, 275 Dendrocincla anabatina, 172 Dendroco/aptes certhia, 172 Dendrocopos pubescens, 39, 382 scalaris, 75, 174 villosus, 382 Dendrocygna autumnalis, 43, 174 Dendroica caerulescens, 40 castanea, 40, 65, 385 coronata, 65, 119, 383 discolor, 303 jusca, 64, 383 magnolia, 65, 303, 383 pensylvanica, 40, 71, 190, 383 petechia, 67, 103, 190, 383 pinus, 40 striata, 40 tigrina, 65, 118, 385, 458 virens, 40, 64, 190, 383 Dennis, John V., Damage by Golden- fronted and Ladder-hacked w^ood- peckers to fence posts and utility poles in South Texas, 75-88 de Vlaming, Victor L., Regurgitation by Killdeer as a possible means of dis- persal for seeds and aquatic organisms, 449-450 Diamond, Jared M. and John W\ Terborgli, Observations on bird distribution and feeding assemblages along the Rio December 1Q67 Vol. 79, .\o. 4 INDEX TO VOLUME 79 477 Callaria, Department of Loreto, Peru, 273-282 Dicaeum agile, 153 concolor, 153 criientatum, 145 trigonostigmum, 153 Dicrurus annectans, 152 paradiseus, 152 Distribution, 6, 118, 155-161, 163-186, 236, 241, 242, 245, 273-282, 340, 347, 348, 371-396 Dives dives, 173 Donacobius atricapillus. Til Dove, Common Ground, 182 Mourning, 39, 244, 271, 375, 382, 450, 451 Dowitcher, 221 Short-billed, 314 Drongo, Crow-billed, 139, 152 Large Racquet-tailed, 137, 138, 139, 140, 141, 142, 145, 146, 152 Drongo-Cuckoo, 152 Dryocopus lineatus, 174 pileatus, 78, 382, 452 Duck, Black, 38, 220, 238, 239 Black-bellied Tree, 43-49 Ring-necked, 220 Ruddy, 220 Wood, 38, 237-239, 264, 268, 269, 339, 377 Dumetella carolinensis, 39, 103, 294, 383, 451 Dunlin, 307, 314 Dusi, Julian L., Migration in the Little Blue Heron, 223-235 Eagle, Bald, 155, 441-448 Golden, 38, 446 Ecology, 7, 131-154, 163-187, 188-199, 200- 207, 208-218, 259-272, 273-279, 371- 396 Edeburn, Ralph M., Abnormal tongue in a Robin, 120 Edwards, Ernest P., review by, 123-124 Egret, Cattle, 181, 236, 245 Common, 236-237, 245 Snowy, 181, 236-237, 245 Egretta thula, 236 Einarsen, Arthur S., The Black Brant: Sea Goose of the Pacific Coast, reviewed, 126-127 Elainia flavogaster, 173 obscura, 344 Elanoides forficatus, 155, 275 Elunus leucurus, 174 Emberiza citrinella, 436 rustica, 24 Emerald, White-bellied, 178 Empidonax breivsteri, 374 flavescens, 172 /. imperturbatus, 179 flaviventris, 382 minimus, 39, 382 traillii, 382 virescens, 39, 380 Eremophila alpestris, 208 a. praticola, 210, 212 Ereunetes mauri, 314 pusillus, 221, 307 Erithacus rubecula, 432 Erolia alpina, 307 bairdii, 314 melanotos, 221, 307 minutilla, 39, 307 Eubucco richardsoni, 276 Eucometis penicillata, 173 Eudocimiis albus, 174 Euphagus carolinus, 41 Euphonia, Blue-headed, 184 Scrub, 178 Yellow-throated, 178, 184-185 Euphonia afjinis, 173, 178 gouldi, 173 lauta, 173, 178, 185 musica, 173, 184 Eurylaimus javanicus, 152 ochromalus, 152 Eurypyga helias, 275 Euscarthmornis granadensis, 344 Euxenura maguari, 316, 317 Evans, Raymond N., Nest site movements of a Poor-will, 453 Falco albigularis, 173 jemoralis, 174 rufigularis, 275 sparverius, 38 Feduccia, J. Alan, The amphirhinal con- dition in the Passeriformes, 453-455; 478 THE WILSON BULLETIN December 1967 Vol. 79, .No. 1 Ciconia maltha and Gras americana from the Upper IMiocene of Idaho, 316-321 Ferguson, Denzel E., A possible case of egg transport hy a Chuck-wilFs-widow, 452-453 Ficken, Millicent S. and Roi)ert W. Ficken, Age-specific differences in the breed- ing behavior and ecolog^^ of the Amer- ican Redstart, 188-199 Ficken, Rol)ert W., see Chappell, Janet S. and ; Ficken, Millicent S. and ; My ton, Becky A. and Finch, House, 94, 102, 105 Purple, 41, 384, 385, 392 Fisher, James, The Shell bird hook, re- viewed, 468-469 Flicker, 5-21 Yellow-shafted, 270, 374, 375, 377, 382 Flight, 238-239, 405-406, 423-428 Flight speed, 238-239 Florida caerulea, 174, 223, 245 l lowerpecker. Crimson-breasted, 145, 153 Orange-bellied, 139, 153 Plain, 153 Scarlet-hacked, 145 Thick-hilled, 153 Yellow-throated, 153 Flycatcher, Acadian, 39, 264, 267, 380 Ash-throated, 86 Black-naped Blue, 137, 152 Brown, 153 Brown-crested, 183 Chestnut-winged, 153 Gray-capped, 115 Great Crested, 264, 267, 270, 377, 382 Grey-headed, 137, 139, 142, 152 Least, 39, 382 Olive-sided, 382, 385, 389 Paradise, 137, 138, 139, 140, 141, 145, 146, 148, 152 Scissor-tailed, 236 Sepia-capped, 183 Siberian, 153 Social, 115 Spotted Fantail, 137, 138, 139, 142, 143, 144, 146, 152 TickelTs Blue, 152 Traill’s, 374, 375, 382, 385, 392 Verditer, 137, 139, 142, 146, 152 Yellow-bellied, 382, 385 Flycatcher-shrike, Bar-winged, 137, 139, 140, 141, 142, 143, 144, 146, 152 Black-winged, 139, 152 Flyeater, 137, 138, 139, 142, 143, 144, 153 Food habits, 43-49, 115-116, 119, 200 206, 214, 307-315, 319-321, 339-340, 341, 441_448, 455-456 Forest-Falcon, Barred, 181 Formicarius analis, 172 Forsyth, Billy J., see Bolen, Eric G. and Forsythe, Dennis M., Egg teeth and hatch- ing methods of the Long-hilled Curlew, 340-341 Fossils, 316-318 Fregata magnificens, 174, 175 French, William L., A Sage Thrasher in Massachusetts, 241 Frigatehird, Magnificent, 175 Fringilla coelebs, 94 montifringilla, 107 Frohling, Robert C., Bonaparte’s Gull feeding on walnut meat, 341 Fulica americana, 39, 221, 341 Fulk, George W., The gaping response of nestling Bank Swallows, 344^345 Furnarius leucopus, 277 Gadwall, 220, 221 Galbalcyrhynchus leucotis, 276, 280 Galbula cyanescens, 276 rujicaucla, 173, 183 Gallinule, Purple, 182 Gannet, 38 Garrulax, 455 Gaunt, Abbot S. and Sandra L., Cavity “excavation” hy Cliff Swallows, 110- 113 Gaunt, Sandra L., see Gaunt, Abbot S. and Gavia adamsii, 416 arctica, 416 immer, 38, 416, 418 stellata, 418 Geothlypis trichas, 103, 342, 383 Geotrygon laivrencii, 172, 177, 182 /. carrikeri, 179 December 1067 Vol. 79, x\o. 4 INDEX TO VOLUME 79 479 inontana, 172 Gerygone fusca, 153 Glaucidium brasilianum, 173 Gnatcatcher, Blue-gray, 264, 267, 270 Goddard, Stephen V. and Veryl V. Board, Reproductive success of Red-winged Blackbirds in North Central Okla- homa, 283-289 Godfrey, W. Earl, The Birds of Canada, reviewed, 463-466 Goldcrest, 200 Goldfinch, American, 41, 89-109, 348, 375, 384, 385 Eastern, 380 European, 91, 104, 105, 106, 107 Lawrence’s, 105, 106, 107 Lesser, 104, 106, 107 Goose, Canada, 38, 242, 244 Lesser Snow, 38 Gould, John, Birds of Europe, reviewed, 255-256 Crackle, Boat-tailed, 350 Common, 41, 287, 377, 383, 455 Grallaria guatimalensis, 172, 177 Grant, C. Val, Breeding behavior of an uniquely marked Starling, 243-244 Graybird, Hook-billed, 144, 152 Lesser, 137, 152 Grebe, Eared, 221, 341 Horned, 38 Least, 180 Pied-billed, 180, 221, 325 Red-necked, 221 Greenfinch, 104, 105, 107, 436 Grosbeak, Rose-breasted, 41, 384, 385 Grouse, Ruffed, 28-36, 377, 382 Sharp-tailed, 449 Grus americana, 155, 157, 316-318 canadensis, 157, 316, 317 Gull, Bonaparte’s, 221 California, 341 Franklin’s, 221 Herring, 39, 421-431 Ring-hilled, 39, 221, 341 Western, 242-243 Gymnostinops montezuma, 173, 178 Habia gutturalis, 174 rubica, 173, 185 Habitat, 65-66, 77, 163-180, 188-189, 200- 206, 208-210, 371-396 Haliaeetus leucocephalus, 441 Hall, George A., review by, 467-468 Hanson, Harold C., The Giant Canada Goose, reviewed, 125-126 Harpactes duvauceli, 152 Harpagus bidentatus, 173, 181 Harrison, C. J. 0., The double-scratch as a taxonomic character in the Holarctic Emberizinae, 22-27 Harrison, Thomas P., review by, 255 Harting, James Edmund, The Birds of Shakespeare. Including of Men and Birds: Prolegomena to the birds of Shakespeare by Grundy Steiner, re- viewed, 255 Haverschmidt, F., review by, 466-467 Hawfinch, 105 Hawk, Bicolored, 181 Broad-w inged, 38, 54, 267, 405 Cooper’s, 38 Marsh, 38, 54, 221, 222, 375, 382 Red-shouldered, 38, 264, 269 Red-tailed, 38, 54 Rough-legged, 54 Sharp-shinned, 50, 56-61, 397-415 Short-tailed, 181 Sparrow, 367 White, 181 Zone-tailed, 181 Hawk-Eagle, Black, 181 Heliomaster longirostris, 174 Heliornis fulica, 175 Helmitheros vermivorus, 40 Hemicircus concretus, 152 Hemipus hirundinaceus, 152 picatus, 152 Henicorhina leucostica, 172 Heron, Black-crowmed Night, 221 Great Blue, 456 Green, 180-181, 245 Little Blue, 222-235, 245 Herpetotheres cachinnans, 173 Himantopus mexicanus, 341 Hirundo riistica, 382 Hofslund, Pershing B., Proceedings of the forty-eighth annual meeting, 358-368 480 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Holcoml), Larry C., Goldfinch accept young after long and short incubation, 348; Mourning Dove egg in nests of (iathird and Rohin, 450-451 Honeycreeper, Red-legged, 178, 184 Howard, Deborah V., Variation in the breeding season and clutch-size of the Rohin in the northeastern United States and the Maritime Provinces of Canada, 432-440 Hubbard, John P., Notes on some Chiapas birds, 236 Hummingbird, .Amethyst-throated, 183 Ruby-throated, 264, 267, 375 Hydranassa tricolor, 174 Hylocichia fuscescens, 40, 383 guttata, 40, 383 mustelina, 39, 383 ustulata, 383 Hylomanes momotula, 172 Hylophilus decurtatus, 173 ochraceiceps, 172 Hypomorphnus urubitinga, 174, 175 Hypothymis azurea, 153 Hypsipetes charlottae, 152 criniger, 152 j/avalus, 152 viridescens, 152 Icteria virens, 40, 118 Icterus chrysater, 174 cucuUatus, 173, 184 galbula, 41, 196 gu laris, 174 icterus, 211, 280 mesomelas, 173 prosthemelas, 173 spurius, 41, 193, 196 wagleri, 173, 184 Ictinia misisippiensis, 38 Incubation, 212, 348, 434, 435 lora. Great, 152 Green, 137, 139, 140, 141, 142, 143, 144, 145, 146, 152 Irena puella, 152 Iridoprocne albilinea, 175 bicolor, 382 Ixobrychus exilis, 174, 181 Jabiru mycteria, 275, 316, 317 Jacamar, Rufous-tailed, 183 Jacana jacana, 275 spinosa, 175 Jay, Blue, 39, 264, 267, 270, 271, 346, 376, 377, 380, 382, 393 Crested .Malay, 145 Johnson, A. \\ ., The birds of Chile and adjacent regions of Argentina, Bolivia and Peru. Volume I, reviewed, 124— 125 Junco, Oregon, 106 Slate-colored, 42, 384, 385 Junco hy emails, 42, 384 oreganus, 106 Keith, Stuart, review hy, 251-254 Kenyon, Karl W., review hy, 126-127 Kepler, Cameron B., review hy, 469-471 Kestrel, American, 38 Killdeer, 39, 221, 314, 450 Kingbird, Eastern, 382 Kingfisher, Belted, 236-237, 264 Kinglet, Golden-crowned, 40, 383, 385 Ruby-crowned, 40 Kite, Double-toothed, 181 Hook-billed, 181 Mississippi, 38 Sw^allow-tailed, 155 Klopfer, Peter H., Behavioral stereotypy in birds, 290-300 Kress, Stephen W., A Robin nests in winter, 245-246 Laboratory Equipment, 335-338 Lack, David, Population studies of birds, reviewed, 469-471 Lampornis amethystinus, 172, 183 Lanio aurantius, 173 Lanius cristatus, 152 excubitor, 117 ludovicianus, 40, 116 Lansdowne, James Fenwick, Birds of the Northern Forest, reviewed, 249-251 Lark, Horned, 208-218 Prairie Horned, 210 Larus argentatus, 39, 421 californicus, 341 delawarensis, 39, 341 occidentalis, 242 Laterallus ruber, 174, 182 Laybourne, Roxie C., see Short, Lester L.. Jr. and December 1967 Vol. 79, No. i INDEX TO VOLUME 79 481 Leafbird, Greater Green, 137, 138, 139, 142, 143, 144, 145, 146, 152 Lesser Green, 137, 138, 139, 142, 143, 144, 145, 146, 152 Yellow-headed Green, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 152 Legatus leucophaius, 173 Lepidocolaptes affinis, 172 lachrymiger, 344 souleyetii, 170, 172 Lepidogrammus cumingi, 322 Leptopogon amaurocephalus, 172, 183 Leptotila plumbeiceps, 172 verreauxi, 172 Leucophoyx thula, 174, 181, 245 Leucopternis albicollis, 172, 181 Limnodromus, 221 griseus, 314 Lokemoen, John T., Flight speed of the Wood Duck, 238-239 Lonchura striata, 153 Longcore, Jerry R., Unusual behavior of the Yellow-headed Blackbird, 117-118 Longspur, Lapland, 23 Loon, Arctic, 416 Common, 38, 416, 417, 418, 419 Red-throated, 418 Yellow-billed, 416 Lophodytes cucuUatus, 38 Loriculus galgulus, 152 Loxia curvirostra, 196, 344 leucoptera, 196 Macinnes, Charles D., review by, 125-126 Macronus gularis, 152 Magpie, Black-crested, 145 Malacopteron affine, 152 cinereum, 152 magnum, 152 Malcoha, Chestnut-breasted, 137, 139, 140, 141, 145, 146, 152 Lesser Green-billed, 145, 152 Raffles, 139, 145, 152 Red-billed, 152 Rufous-bellied, 145, 152 Mallard, 38, 220, 221, 222, 239, 339, 375, 450 Manuwal, David A., Observations on a localized duck sickness in the Delta Marsh; summer, 1964, 219-222 Mareca americana, 38, 221 Alartin, Elden W., An improved cage design for experimentation with pas- seriform birds, 335-338 Martin, Purple, 196 Martinez, Aida, see McNeil, Raymond and Mayfield, Harold, review by, 123 McClure, H. Elliott, The composition of mixed species flocks in lowland and sub-montane forests of Malaya, 131- 154 McMillen, Wheeler, Bugs or People? re- viewed, 256 McNeil, Raymond and Aida Martinez, Re- tarded or arrested cranial development in Myiornis ecaudatus, 343-344 Meadowlark, Eastern, 41, 376 Western, 41 Measurements, 8-10, 345-346 Megaceryle alcyon, 236-237 Megalaima australis, 152 chrysopogon, 152 henrici, 152 mystacophanes, 152 Megarhynchus pitangua, 116, 173 Meiglyptes tristis, 152 Melanerpes cruentatus, 276, 280 erythrocephalus, 39 formicivorus, 174, 175 Melanochlora sultanea, 153 Meleagris gallopai o, 239 Melophus lathami, 24 Melopsittacus undulatus, 328-333 Melospiza georgiana, 22, 103, 384 melodia, 22, 42, 192, 384, 437 Merganser, Hooded, 38 Merops viridis, 152 Mesembrinibis cayennensis, 275 Meyerriecks, Andrew J. and David W. Nellis, Egrets serving as “beaters” for Belted Kingfishers, 236-237 Micrastur ruficoUis, 172, 181 semitorquatus, 172, 182 Micropalama himantopus, 307 Migration, 50-63, 223-235, 236, 307-315, 397-415 Milvago chimachima, 275 Mirnus polyg/ottos, 174, 183, 246 482 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Minivet, Ashy, 139, 145, 152 Fiery, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 152 Scarlet, 137, 138, 139, 140, 141, 142, 143, 144, 146, 152 Mionectes striaticollis, 344 Mniotilta varia, 40, 383 M()ckingi>ird, Common, 183, 246 Molothrus (Iter, 41, 118, 383, 435 bonariensis, 344 Molts and plumages, 11-19, 113-114, 189, 214-215, 239-240, 322-327, 339, 416- 420, 442, 456-458 Momotus momota, 172, 276 Monasa nigrijrons, 276 Montgomery, Robert A., Observation of Brant in southern Illinois, 242 Morse, Douglass H., The contexts of songs in Black-throated Green and Black- burnian warblers, 64-74 Mortality, 219-222, 447 Morus bassanus, 38 Mueller, Helmut C. and Daniel D. Berger, \^ind drift, leading lines, and diurnal migration, 50-63; Fall migration of Sharp-shinned Hawks, 397-415 MuUeripiciis pulverulentus, 152 Munia, Sharp-tailed, 153 Muscicapa latirostris, 153 sibirica, 153 thalassina, 152 tickelliae, 153 Muscivora foriicata, 236 tyrannus, 174 Myadestes ralloides, 344 unicolor, 172, 177 Mycteria americana, 174, 275 Myiarchus cinerascens, 86 crinitus, 382 tuberculijer, 173 tyrannulus, 173, 183 Myiobius sulphureipygius, 172 miniatus, 173, 177 m. molochinus, 179 Myiodynastes luteiventris, 173 maculatus, 173 Myiopagis viridicota, 173, 344 Myiornis ecaudatus, 343, 344 Myiozetetes granadensis, 115, 116 simi/is, 115, 116, 173 Myospiza aurijrons, 277 Myton, Becky A. and Robert W. Ficken, Seed-size preference in chickadees and titmice in relation to ambient tempera- ture, 319-321 Necturina hypogrammica, 153 Nellis, David W., see Meyerriecks, Andrew J. and i Nesoceleus) jernandinae, 5 Nesting, 110-113, 211-216, 245-246, 259- 272, 283-289, 346, 341, 348, 432-440, 451^52, 453 Nethersole-Thompson, Desmond, The Snow Bunting, reviewed, 353-354 Nice, Margaret M., review by, 353-354 Niedrach, Robert J., see Bailey, Alfred M. and Nighthawk, Common, 343 Numenius americanus, 158, 340-341 Nuttallornis borealis, 382 Nuthatch, Brown-headed, 39, 267, 268, 269, 270, 271 Red-breasted, 382, 386, 389, 392 Velvet-fronted, 137, 139, 142, 143, 144, 146, 153 White-breasted, 264, 267, 270, 377, 382, 385 N yctanassa violacea, 174 Nyctea scandiaca, 158 Nyctibeus griseus, 173 \ ycticorax nycticorax, 174 \yctidronius albicollis, 173, 276 Nyctiornis amictus, 152 Ochthornis littoralis, 277 Odontophorus guttatus, 172 Ogden, John C. and Frank L. Chapman, Extralimital breeding of Painted Bun- tings in Florida, 347 Oldsquaw, 239 Olrog, Claes Chr., review by, 124-125 Oncostoma cinereigulare, 172 Onychorhynchus mexicanus, 172 Oporornis jormosus, 40 Oreoscoptes montanus, 241 Oriole, Baltimore, 41, 196 Black-headed, 137, 138, 139, 140, 141, 146, 152 December 1967 Vol. 79, No. 4 INDEX TO VOLUME 79 483 Hooded, 184 Orchard, 41, 193, 196, 271 Wagler’s, 184 Orioliis xanthonotus, 152 Ornithion semiflaviim, 172 Oropendola, Chestnut-headed, 184 Montezuma, 178 Or tails guttata, 275, 280, 281 vetula, 173 Orthotomus atrogularis, 153 Otus asio, 39 choliba, 276 guatemalae, 172 Ovenbird, 40, 264, 267, 268, 270, 305, 377, 378, 379, 380, 383, 385, 386, 387, 393 Owl, Barn, 39, 451-452 Barred, 39, 264, 377 Great Horned, 39, 159 Screech, 39, 267, 270 Short-eared, 39 Snowy, 158, 159 Spectacled, 183 Striped, 183 Owre, Oscar T., Predation by the Chuck- will’s-widow upon migrating warblers, 342 Pachyramphus major, 173 Packard, Gary C., Seasonal variation in bill length of House Sparrows, 345-346 Paphosia helenae, 173, 183 Parakeet, Barred, 182 Blue-crowned Hanging, 152 Carolina, 158 Olive-throated, 178 Parasitism, 341, 435, 450-451 Parkes, Kenneth C., Prealternate molt in the Summer Tanager, 456-458 Parmalee, Paul W., Additional noteworthy records of birds from archaeological sites, 155-162 Paroaria gularis, 277 Parrot, Brown-headed, 182 Parula americana, 68, 303, 383 pitiayumi, 173, 184 Paras, 200, 204 atricapi/lus, 200, 382 atricristatus, 174 bico/or, 39, 118, 319, 346 carol inensis, 319 hudsonicus, 204 montanus, 200 prehudsonicus, 205 rujescens, 200 Passer, 455 domesticus, 41, 86, 118, 170, 345, 347 Passerculus sandwichensis, 41, 117 Passerel/a iliaca, 22, 42 Passerina ciris, 347 cyanea, 41, 102 Pedioecetes phasianellus, 449 Pelecanus erythrorhynchus, 221 occidentalis, 174, 175 Pelican, Brown, 175 White, 221 Penelope purpurascens, 172 Pericrocotus divaricatus, 152 jlammeus, 152 igneus, 152 Pesticides, 441-448 Petrochelidon pyrrhonota, 110 Pettingill, Olin Sewall, Jr., review by, 255-256, 352-353, 468-469; see Arbih, Robert S. Jr., and Peucedramus taeniatus, 236 Pewee, Eastern Wood, 264, 267, 270, 377, 382, 385, 393 Phaenicophaeus chlorophaeus, 152 curvirostris, 152 diardi, 152 javanicus, 152 sumatranus, 152 Phaethornis longuemareus, 172 superciliosus, 172 Phaetiisa simplex, 276, 278 Phainopepla, 192 Phainopepla nitens, 192 Phalacrocorax olivaceus, 174, 180, 278 Phalaenoptilus nuttallii, 453 Phalarope, Wilson’s, 221, 307, 314 Phasianus colchicus, 341 Pheasant, Ring-necked, 341 Pheucticus ludovicianus, 41, 384 Philentoma pyrrhoptera, 153 Phillips, Richard S., Buff-breasted Sand- piper in northwestern Ohio, 340 Philohela minor, 340 Philydor lichtensteini, 455 raj us, 455 484 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 l^hloeoceastes guatemalensis, 170, 172, 236 melano/eucos, 276, 281 Phlogothraupis sangiiinolenta, 174 Phoebe, Eastern, 382, 385 Phylloscopus borealis, 153 l^hysiology, 242-243, 328-333 Piaya cay ana, 173, 276, 280 Piculus rubiginosus, 170, 173 Picas mentalis, 152 miniaceus, 152 puniceus, 152 Pigeon, Lesser Thick-hilled Green, 152 Passenger, 157 Scaled, 182 Pigmy-tyrant, Short-tailed, 343 Pilherodius pileatus, 275 Pintail, 38, 220, 221, 222, 239 Pionopsitta haematotis, 172, 182 Pipilo erythrophthalmus, 41, 384 juscus carolae, 238 Pipit, Water, 40, 208 Pipra mentalis, 172 Pipromorpha oleaginea, 172 Piranga leucoptera, 173, 236 olivacea, 41, 383, 456 rubra, 456 r. cooperi, 457 r. rubra, 457, 458 Pitangus sulphuratus, 116, 173, 277 Platylophus galericulatus, 145 Platypsaris aglaiae, 173 Platyrinchus mystaceus, 172 Platysmurus leucopterus, 145 Plectrophenax nivalis, 23 Plover, American Golden, 314 Black-bellied, 39, 314 Semipalmated, 221, 314 Pluvialis dominica, 314 Podiceps auritus, 38 caspicus, 341 dominicus, 174, 180 Podilymbus podiceps, 174, 180, 325 Polioptila caerulea, 174 Polyborus cheriway, 174 Pomatorhinus montanus, 152 Pooecetes gramineus, 42 Poor-will, 453 Populations, 66, 77-78, 259-272, 371-396 Porphyrula martinica, 175, 182 Porzana Carolina, 382 Prairie Ghicken, (Greater, 449 Predation, 116, 236-237, 342, 449 Prescott, Kenneth W., Unusual activities of a House Sparrow and a Blue Jay at a Tufted Titmouse nest, 346-347 l^resident’s Science Advisory Gommittee — Environmental Pollution Panel, Restor- ing the (juality of our environment, reviewed, 357 Prinia rujescens, 153 Prionochilus maculatus, 153 percussus, 153 Progne chalybea, 174 subis, 196 Psarocolius, 277, 280 Psilorhinus morio, 173 Psomocolax oryzivorus, 173 Pteroglossus beauharnaesii, 322, 323, 324 castanotis, 276, 281 inscriptus, 276, 281 torquatus, 173 Pulsatrix perspicillata, 172, 183 Pycnonotus atriceps, 152 brunneus, 152 cyaniventris, 152 dispar, 152 erythropthalmos, 152 eutilotus, 145 jinlaysoni, 152 melanoleucos, 152 simplex, 152 squamatus, 152 Pygiptila stellaris, 277 Pyrocephalus rubinus, 174, 277 Quail, Ocellated, 236 Quail-Dove, Purplish-backed, 177, 182 Quelea quelea, 344 Quiscalus quiscula, 41, 287, 383, 455 Rail, Red, 182 Virginia, 382 Rail us aquaticus, 324 elegans, 323, 324 indicus, 323, 324 limicola, 382 longirostris, 323, 324 Ramphastos suljuratus, 173 tucanus, 276, 280, 281 Ramphocaenus rujiventris, 173 December 1967 Vol. 79, No. 4 INDEX TO VOLUME 79 485 Ramphoceliis carbo, 211, 281 dimidiatus, 293 Rand, A. L., A Common Crackle learning to soak bread, 455-456 Raven, Common, 157, 160 Redhead, 220, 221 Redstart, American, 103, 188-199, 264 Painted, 246 Slate-throated, 177 Regulus calendula, 40 regulus, 200 satrapa, 40, 383 Rhinoptynx clamator, 174, 183 Rhipidura perlata, 152 Rhynchocycliis brevirostris, 172 Richmondena cardinalis, 41, 174, 294, 383 Riparia riparia, 110, 344 Roadrunner, 269 Robbins, Chandler S., Bertel Bruun and Herbert Zim, Birds of North America. Illustrated by Arthur Singer, reviewed, 251-254 Robin, 39, 119-120, 245-246, 375, 376, 383, 432-439, 450 Black, 184 Clay-colored, 178 European, 432, 436, 437 White-throated, 178, 184 Rogers, John P., Flightless Green-winged Teal in southeast Missouri, 339 Rostrhamus sociabilis, 174 Sabrewing, Wedge-tailed, 170 Saltator atriceps, 174 coerulescens, 174, 277 maximus, 174 Sanderling, 314 Sandpiper, Baird’s, 314 Buff-breasted, 314, 340 Least, 39, 221, 307, 310, 314 Pectoral, 221, 307, 310, 314, 315 Semipalmated, 221, 307, 313, 314, 315 Solitary, 314 Spotted, 221, 314 Stilt, 221, 307, 308, 310, 314 Western, 314 Sapsucker, Yellow-bellied, 39, 382, 386 Sarcoramphus papa, 174, 375 Sayornis nigricans, 175 phoebe, 382 Scardafella inca, 174 Scaup, Lesser, 38, 220, 341 Schreiber, Ralph W,, Roosting behavior of the Herring Gull in central Maine, 421-431 Seedeater, White-collared, 175 Seiurus aurocapillus, 40, 305, 383 noveboracensis, 383 Serinus, 104 Setophaga picta, 246 ruticilla, 103, 188 Shama, Common, 153 Short, Lester L,, Jr., Variation in Central American flickers, 5-21 Short, Lester L., Jr. and Roxie C. Lay- bourne, An instance of “white wing- barring” in the Common Crow, 113- 114 Shoveler, 220, 222, 314 Shrike, Brown, 152 Loggerhead, 40, 116-117 Northern, 117 Sialia sialis, 346, 375 Siskin, 105 Black-capped, 236 Sitta canadensis, 382 carolinensis, 382 frontalis, 153 pusilla, 39 Sittasomus griseicapillus, 172 Skinner, Robert W., see Stewart, Paul A. and Skutch, Alexander F., Cape May Warbler in Costa Rica, 118-119 Smaragdolanius pulchellus, 172 Smith, Susan M., An ecological study of winter flocks of Black-capped and Chestnut-backed Chickadees, 200-207 Snipe, Common, 39, 307, 313, 314, 315 Snyder, Dorothy E., The Birds of Guyana (formerly British Guiana): A Check list of 720 species with brief descrip- tions, voice and distribution, reviewed, 466-467 Solitaire, Slate-colored, 177 Sora, 382 Sparrow, Black-throated, 23 Chipping, 103, 270, 271, 294 Field, 374, 375, 376, 393 486 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 Vox, 22, 42 Cirasshopper, 42 House, 41, 86, 118, 170, 271, 345-346 Olive, 23 Kufous-erowned, 348-349 Hufous-naped, 22 Savannah, 41, 117 Seaside, 42 Sharp-tailed, 42 .Song, 22, 42, 192, 373, 375, 376, 377, 378, 379, 380, 384, 385, 386, 393, 437 Swamp, 22, 103, 384, 385 Tree, 22, 335 Vesper, 42 White-crowned, 42, 243-244 White-throated, 23, 42, 384, 386, 392 Spatula clypeata, 221, 341 Sphyrapicus varius, 39, 382 Spiderhunter, Grey-breasted, 153 Lesser Yellow-eared, 139, 153 Little, 139, 145, 153 Long-billed, 153 Spinus atriceps, 236 lawrencei, 105 psaltria, 104, 174 spinus, 105 tristis, 41, 89, 348, 384 Spizaetus tyrannus, 172, 181 Spizella arborea, 22, 335 passerina, 103, 294 pusilla, 375 .Spofford, Sally Hoyt, Tongue deformity in immature Robin, 119-120; see Arhih, Robert S., Jr. and Sporophila castaneiventris, 278, 280 torqueola, 174, 175 Squatarola squatarola, 39, 314 Stachyris maculata, 152 nigricoUis, 145 Starling, 40, 55, 243-244, 271 Stefferud, Alfred, editor. Birds in our lives, reviewed, 467-468 Steganopus tricolor, 307 Steiner, Grundy, see Harting, James Ed- mund and Stelgidopteryx ruficollis, 174, 277 Stereotypy, 290-300 Sterna superciliaris, 276, 278 Stewart, Paul A., Wood Duck ducklings captured by bullfrogs, 2.37-238; Dis- gorging of food by Wood Ducks, 339- .340; see Chura, Nicholas J. and .Stewart, Paul A. and Robert W. Skinner, Weights of birds from Alabama and North Carolina, 37-42 Stilt, Black-necked, 341 Stork, European, 54 Streptoprocne zonaris, 174, 175 Strix varia, 39, 377 Sturnella magna, 41, 174 neglecta, 41 Sturnus vulgaris, 40, 55, 243 Sunbird, Purple-naped, 145, 153 Ruby-cheeked, 153 Rufous-throated, 153 Scarlet, 153 Yellow-backed, 153 Surniculus lugubris, 152 Sutton, George Miksch, review by, 249- 251; 463-466 Swallow, Bank, 110-113, 344-345 Barn, 382 Cliff, 110-113 Tree, 375, 382, 392 Swift, 437 Chimney, 264, 267, 270 Vaux’s, 175 White-collared, 175 Synallaxis albescens, 344 erythrothorax, 173 T achycineta al biventer, 277 Tailorbird, Black-necked, 153 Tanager, Blue, 293, 298 Crimson-backed, 293 Scarlet, 41, 270, 377, 383, 385, 387, 393, 456 Summer, 270, 456-458 Yellow-winged, 178 White-winged, 236 Tanagra laniirostris, 277 xanthogaster, 344 Tangara chilensis, 277, 280, 281 Tangavius aeneus, 173, 175 Tapera naevia, 173 Taraba major, 173, 183 Taxonomy, 5-21, 22-27 Deccinbcr 1967 \'(>1. 79, No. 1 INDEX TO VOLUME 79 487 Teal, Blue-winged, 220, 221, 222 Cinnamon, 341 Green-winged, 220, 339 Telmatodytes palustris, 39 Tephrodornis gularis, 152 Terborgh, John W., see Diamond, Jared M. and Tern, Black, 221 Forster’s, 221 Royal, 39 T erpsiphone paradisi, 152 Thalasseus maximus, 39 Thamnophilus doliatus, 173 Thompson, Daniel Q., review hy, 256, 357 Thrasher, Brown, 39, 375, 383 Sage, 241 Thraupis abbas, 174, 178 cana, 293 Virens, 174 Thrush, Hermit, 40, 383, 385 Mistle, 432 Song, 432, 436 Swainson’s, 383, 385 Wood, 39, 264, 267, 270, 377, 383 Thryomanes bewickii, 86 Thryothorus cor ay a, 277 maculipectus, 173 Tiaris olivacea, 174 Tigrisoma, 275 Tinamus major, 172 Tit, Sultan, 139, 153 Willow, 200 Titmouse, Tufted, 39, 118, 264, 267, 270, 319-321, 346, 377 Tityra, 211, 280 inquisitor, 173 semijasciata, 173 Tolmomyias sulphurescens, 172 Tomer, John S., Cattle Egret nesting in northeastern Oklahoma, 245 Tomlinson, Jack T., Sedatives interfere with walking more than flying, 242- 243 Totanus jlavipes, 221, 307 melanoleucus, 307 Towhee, Brown, 238 Green-tailed, 23 Rufous-sided, 41, 374, 375, 376, 377, 384, 385, 393 T oxostoma rujum, 39, 383 Treron curvirostra, 152 T richastoma bicolor, 145 Tringa jlavipes, 275 solitaria, 276, 314 Troglodytes aedon, 382 musculus, 173, 183 troglodytes, 383 Trogon, Red-rumped, 139, 145, 152 Trogon citreolus, 174 collaris, 172, 276, 280, 281 massena, 172 violaceus, 172 viridis, 276, 280, 281 Tryngites subruficollis, 314, 340 T Urdus assimilis, 172, 178, 184 ericetorum, 432 grayi, 173, 178 injuscatus, 172, 184 merula, 432 migratorius, 39, 119, 120, 245, 383, 450 viscivorus, 432 Turkey, 155, 157, 159, 239-240, 264, 269 Tympanuchus cupido, 449 Tyrannus melancholicus, 116, 173, 277 tyr annus, 382 Tyto alba, 39, 174, 451 Uropsila leucogastra, 174 Van Tyne, Josselyn, 343 Veery, 40, 375, 377, 380, 383, 386 V eniliornis fumigatus, 173 Verbeek, Nicholaas A. M., Breeding biology and ecology of the Horned Lark in Alpine tundra, 208-218 Vermeer, Kees, Foreign eggs in nests of California Gulls, 341 V ermivora celata, 40 chrysoptera, 40, 190, 301 peregrina, 383 pinus, 40, 190, 301 rujicapilla, 40, 303, 383 Violetear, Green, 183, 236 Vireo, Red-eyed, 40, 264, 267, 270, 377, 383, 385 Solitary, 40, 385 Yellow-throated, 377 White-eyed, 264, 267, 299 Vireo jlavijrons, 377 griseiis, 294 488 THE WILSON BULLETIN December 1967 Vol. 79, No. 4 olivuceus, 40, 173, 383 solitarius, 40, 385 Voice. 6V-74, 210-211, 214, 328-333 I'olatina jacarina, 174 Vulture, Black, 175 Turkey. 264, 267, 270 Vi’allace, Gary 0., An aggressive display by a Tufted Titmouse. 118 Warbler, Arctic Leaf, 138, 139. 140, 141, 142, 143, 144. 145, 146, 151, 153 Bay-breasted, 40, 65, 385 Black-and-white, 40, 264. 267, 270. 383. 386 Black-tbroated Blue, 40, 386 Black-throated Green, 40, 64-74. 377. 383. 386. 392 Blackburnian, 64-74, 383 Blackpoll, 40 Blue-winged, 40, 301 Brewster’s, 40, 305 Canada, 41, 383, 392 Cape May, 65, 118-119, 342, 385, 458 Cerulean, 264, 268, 269 Chestnut-sided, 40, 71, 72, 383 Golden-crowned, 184 Golden-winged, 301-315 Hooded, 41, 264 Kentucky, 40, 264, 267 Magnolia, 65, 72. 73, 303, 383, 385 Myrtle, 65, 68, 70, 72, 73. 119, 383, 385 Nashville, 40, 303, 374. 375, 383. 389, 392 Olive, 236 Orange-crowned, 40 Parula, 68, 70. 71, 264, 267, 270, 303, 383, 386 Pine, 40, 267, 270 Prairie, 270, 303 Prothonotary, 264. 268, 269 Swainson’s, 264, 268, 269 Tennessee, 383 Tropical Parula, 184 Worm-eating, 40, 264, 268, 269 Yellow, 67, 71, 72, 103, 374, 375, 383. 385 Yellow-throated, 270 aterthrush, Louisiana, 264, 267, 268 Northern, 383 Wauer, Roland H., New status for the Rufous-crowned Sparrow in Utah, 348- 349 Waxwing, Cedar, 40, 103, 322, 375, 383 Weather, 50-63, 397-414, 430 \^ eights, 37-42, 446, 447 Vi'hip-poor-will, 375 V^’hite-eye, Oriental, 153 Wible, Mary, Wing and tail flashing of Painted Redstart, 246 Widgeon, American, 38, 220, 221 Willet, 340 Williams, Lovett E., Jr., Erythrism in the wild Turkey, 239-240 ilson Ornithological Society, Annual report of the Conservation Committee. 461-462 Josselyn Van Tyne Memorial Library Gifts, 199 Membership, 36, 88, 154, 218, 306, 327. 420, 440 Ornithological News. 122, 248, 351. 460 President’s Page, 121, 247, 350, 459 Proceedings of the Annual Meeting. 358-368 W'ilsonia canadensis, 41, 383 citrina, 41 oodcock, 55 American, 340 oodcreeper. Ivory-billed. 184 oodpecker. Acorn. 175 Banded Red, 145, 152 Checker-throated, 152 Crimson-winged, 139, 152 Downy, 39, 264, 267, 270, 377, 382. 385 Flint-billed, 236 Fulvous-rumped. 152 Golden-fronted, 75-88 Golden-olive, 170 Great Slaty, 152 Grey-and-buff, 139, 145, 152 Hairy. 264, 267, 270, 377, 382, 385 Ivory-billed, 159, 160 Ladder-backed. 75-88 Maroon, 152 Orange-backed, 145, 152 Pale-billed, 170 Pileated, 78, 264, 267, 382, 452 Red-bellied, 264, 267, 270 Red-cockaded, 267, 268, 269, 270, 271 Red-headed, 39, 270 Streak-headed, 170 December 1967 Vol. 79, No. 4 INDEX TO VOLUME 79 489 Woolfenden, Glen E., Selection for a delayed simultaneous wing molt in loons ( Gaviidae) , 416-420 Wren, Bewick’s, 86 Carolina, 264, 267, 270 House, 382 Long-billed Marsh, 39 Short-billed Marsh, 39 Southern House, 183 Winter, 383, 385, 392 Wren- Warbler, Lesser Brown, 153 Xanthocephalus xanthocephalus, 117, 195, 287 Xenops minutus, 172 Xiphorhynchus, 277, 455 erythropygius, 454 flavigaster, 172, 184 \ ellowhammer, 436 Yellowlegs, Greater, 221, 307, 314 Lesser, 221, 307, 308, 310, 313, 314 Yellowthroat, 103, 342, 374, 375, 376, 377, 380, 383, 385, 386, 393 Yuhina zantholeuca, 152 Zarhynchus wagleri, 173, 184 Zenaida asiatica, 174 Zenaidura macroura, 39, 244, 382, 450 Zim, Herbert S., see Robbins, Chandler S. and Zonotrichia alhicollis, 23, 42, 384 capensis, 22 leucophrys, 42, 242 Zosterops palpebrosa, 153 This issue of The Wilson Bulletin was published on 29 December 1967 * * ’ * < V- \ V » . f I fv *. # i» 2’ 1I-’ - r- ' - ■ ■ jfjl 'f ^OOuvdlX^it. , l4b*^ MCZ ERNST MAYR LIBRARY 44 1 8 616 267 Date Due JUt-^^=l993