RAPTOR RESEARCH Volume 16 Number ] Spring 1982 RAPTOR RESEARCH Spring 1982 Volume 16, Number 1, Pages 1-32 CONTENTS SCIENTIFIC PAPERS Analysis of Nesting Materials from a Great Basin Ferruginous Hawk Nest— Neil D. Woffinden and Joseph R. Murphy 1 A Survey of Raptors in Northern Utah— James A. Gessaman 4 Winter Roadside Raptor Survey in El Paso County, Colorado, 1962-1979— Elizabeth N. Bauer 10 Helping at the Nest by Yearling Mississippi Kites— James W. Parker and Mark Ports 14 Breeding Biology of Raptors in the Central Appalachians— Cynthia A. Janik and James A. Mosher 18 Unusual Behavior of the Spot-winged Falconet— Roberto Straneck and Guillermo Vasina 25 A Possible Hunting Relationship Between Two Raptor Species— Steven Merchant 26 Food of the Spotted Owl in Utah— Phillip W. Wagner, Carl D. Marti, and Thomas C. Boner 27 THESIS ABSTRACTS 29 BOOK REVIEWS 29 ANNOUNCEMENTS 30 RAPTOR RESEARCH Published Quarterly by the Raptor Research Foundation, Inc. Editor Dr. Clayton M. White, Dept, of Zoology, 161 WIDB, Brigham Young University, Provo, Utah 84602 Editorial Assistant Sandra J. Fristensky, 136 WIDB, Brigham Young University, Provo, Utah 84602 Editorial Staff Dr. Frederick N. Hamerstrom, Jr. (Principal Referee) Dr. Byron E. Harrell (Editor of Special Publications) The Raptor Research Foundation, Inc., welcomes original articles and short notes concerning both diurnal and nocturnal birds of prey. Send all papers and notes for publication and all books for review to the Editor. Most longer articles (20 or more typeset pages) will be considered for publication in Raptor Re- search Reports, a special series for lengthy and significant contributions contain- ing new knowledge about birds or new interpretations of existing knowledge (e.g., review articles). However, authors who pay page costs (currently $36.00 per page) will expedite publication of their papers, including lengthy articles, by ensuring their inclusion in the earliest possible issue of Raptor Research. Such papers will be in addition to the usual, planned size of Raptor Research whenever feasible. SUGGESTIONS TO CONTRIBUTORS: Submit all manuscripts in duplicate, typewritten, double spaced (all parts), on one side of 8V2 X 11 inch paper, with at least 1 inch margins all around. Drawings should be done in India ink and lettered by lettering guide or the equivalent, if possible. Photographs should be on glossy paper. Avoid footnotes. Provide an abstract for all papers more than four double-spaced typed pages in length, not to exceed 5 percent of the total length of the paper. Keep tables at a minimum, and do not duplicate material in either the text or graphs. For advice concerning format refer to the Council of Biological Editors’ Style Manual for Biological Journals or to previous issues of Raptor Research. Proofs will be sent to senior authors only. Major changes in proofs will be charged to the authors. Reprints should be ordered when proofs are returned. MEMBERSHIP DUES: (U.S. funds) $11— US student $13— US regular and foreign student $15— Foreign regular $25— Contributing membership $100— Sustaining membership ow Add $2 to the first three categories if paying after February 15. ANALYSIS OF NESTING MATERIALS FROM A GREAT BASIN FERRU- GINOUS HAWK NEST by Neil D. Woffinden Division of Natural Sciences University of Pittsburgh at Johnstown Johnstown, PA 15904 and Joseph R. Murphy Department of Zoology Brigham Young University Provo, UT 84602 Abstract A newly constructed Ferruginous Hawk (Buteo regalis ) nest was dismantled to deter- mine the species origin, length, diameter and weight of each of the sticks of which it was constructed. Sagebrush (Artemesia tridentata) and juniper (Juniperus osteosperma ) sticks composed 75.58% and 23.26% of the total. No significant deviation existed be- tween sagebrush percent composition of the nest and that of vegetation surrounding the nest. The mean size of juniper sticks in the nest differed significantly from those on the ground in the vicinity of the nest. A possible explanation for the inclusion of rubbish in Ferruginous Hawk nests is offered. Introduction The Ferruginous Hawk ( Buteo regalis ) builds large bulky stick nests, and if available includes items such as paper, plastic sheeting, bones and manure (Weston 1969). In fact, nests have been described composed almost entirely of bleached buffalo bones (Williams and Matteson 1947). The nest cup is usually lined with strips of bark and grass. A new nest may be constructed each year or an old one refurbished and used for sev- eral nesting seasons. The latter practice may result in nests of considerable dimensions. Behle, Woodbury and Cottan (1944) described nests measuring 2 m in height and 3 m in diameter, while Tavener (1919) estimated the height of a nest that had been used for a number of seasons to be 4-5 m. Weston (1969) found that the mean diameter of 24 new- ly constructed nests was approximately 1 m. He also noted that both members of the pair engaged in nest building and once started, worked continuously until the nest was completed. We initiated this study in conjunction with one on nest site selection, in order to de- termine the types and sizes of sticks used in Ferruginous Hawk nest construction. We particularly wanted to know if the birds were selecting a specific type or size of stick or simply using what was conveniently available. Study Site and Methods A newly constructed Ferruginous Hawk nest was located in central Utah (N. latitude 40°00’ and W. longi- tude 111°55’) during June 1980. The area is typical cold desert habitat (Murphy et al. 1969). The nest did not 1 Raptor Research 16(1): 1-4 2 RAPTOR RESEARCH Vol. 16, No. 1 show any signs of use although a single male Ferruginous Hawk was present in the area during each of several nest visits. As the nest was dismantled, the length, diameter, weight and species of each stick were recorded. In addi- tion, the juniper bark lining the nest cup was weighed. The vegetational composition of the area around the nest was determined by counting the number of woody plants in 2 randomly chosen transects, 2 m by 50 m. They originated at the nest tree and extended outward to the north and east along ordinal lines. Two trans- ects were considered sufficient because of the scarcity and uniformity of the existing vegetation. We also ran- domly selected dead juniper sticks, scattered within a radius of 25 m of the nest, and recorded the length and diameter of each. Mean length, diameter and weight were calculated for the juniper and sagebrush sticks of the nest. The mean length and diameter of juniper nest sticks were compared to the means of those found around the nest, using F-tests (P = 0.05). We compared sagebrush percent composition of the nest to that of the surrounding area with a chi-square test (P = 0.05). Results The nest we dismantled was in the top of a juniper 3.2 m in height and as is typical, located at the edge of an open stand (Woffinden 1975). The nest measured 70 X 90 cm, while the nest cup was 30 cm in diameter and lined with 130 g of juniper bark. Mean lengths, diameters and weights of the 258 sticks included in the nest are given in Table 1. Total weight of the nest was 11.13 kg. Sagebrush and juniper sticks were the major constituents; 75.58% and 23.26% respectively. Snakeweed (Xanthocephalum sa- rothrae ), mustard ( Erysimum osperum ) and horsebrush ( Tetradymia canescens) made up the remaining 1.16%. Table 1. Type, Length, Diameter and Weight of Sticks Comprising a Ferruginous Hawk Nest. Type of Stick N Mean Length mm Range SD Mean Diameter mm Range SD Mean Weight g Range SD Juniper 60 481.57 180-1430 246.21 19.65 5-40 8.00 68.00 1-320 64.15 Sagebrush 195 302.41 110-930 111.59 24.45 8-54 7.92 35.35 6-140 28.89 Snakeweed 1 230.00 - - 2.00 _ _ 1.00 _ _ Horsebrush 1 300.00 - - 18.00 - _ 6.00 _ _ Mustard 1 610.00 - - 10.00 - - 26.00 - - Sagebrush was the most commonly occurring woody plant in the area surrounding the nest tree, comprising 62.58% of the total. Snakeweed, horsebrush and juniper were less common with a frequency of 34.4%, 2.79% and 0.23% respectively. No mustard was found in the immediate vicinity, although it grew commonly along the roads in the val- ley. The nest tree was an isolated individual, but 33 other junipers of similar size were counted within a 125 m radius. There was no significant deviation between sagebrush percent composition of the nest and that of the surrounding vegetation (X 2 = 2.31, P = 0.05). Significant differences were noted when mean lengths and diameters of juniper nest sticks were compared to that of those in the surrounding area (F = 18.50, length; F = 69.91, width; P = 0.05). Spring 1982 Woffinden and Murphy— Ferruginous Nest Analysis 3 Discussion The typical Great Basin Ferruginous Hawk nest is a large bulky structure constructed primarily of sagebrush and juniper sticks. Paper, animal dung, plastic, bones, grass and strips of bark are often included. Many raptor species add green leaves and twigs to their nest throughout the nesting season. The purpose of this behavior is not currently understood (Brown and Amadon 1968), although Newton (1979) suggests that it may serve to indicate an occupied nest or territory. Bent (1937) and Lokemoen and Duebbert (1974) described Ferruginous Hawk nests that contained greenery. We have not ob- served this behavior by them in our study area and find literature accounts of such to be quite rare. However, there are numerous descriptions of various types of rubbish being included in Ferruginous Hawk nests (Weston 1969, Bent 1937, Olendorff 1973, Smith and Murphy 1973, Thurow et al. 1980, Williams and Matteson 1947). Perhaps the in- corporation of these atypical materials into the nest of this prairie species satisfies the innate urge of decorating the nest with greenery. The absence of green vegetation in Ferruginous Hawk nests in areas where it is readily available and routinely added to the nests of other sympatric raptors, supports this hypothesis. Nest building is a time and energy demanding activity which undoubtedly would be compounded by active selection of a unique set of materials. The major constituents of Ferruginous Hawk nests differ throughout the range of the species, but it appears that in each area the bulk of the nest is composed of materials that are most readily available. The sagebrush percent composition of the nest we studied did not deviate statistically from that of the vegetation around the nest. Thus, we assumed that there was no spe- cies-specific selection of nesting materials, but choice was a function of availability. However, the juniper sticks in the nest were significantly smaller than those in the sur- rounding area, suggesting that size selection was occurring. Imler (1937) lists the weight of adult male Ferruginous Hawks as 1,237 g (2 individ- uals) and of adult females as 1,983 g (3 individuals). The heaviest juniper stick from the nest weighted 320 g, which is approximately 26% of the male or 16% of the female weights listed above. We have found entire jackrabbit ( Lepus califomicus ) carcasses in Ferruginous Hawk nests; the calculated weight of these was at least 825 g (Haskell and Reynolds 1947). It seems unlikely, then, that a stick of 320 g represents the maximum manageable size for this large raptor. Rather, it appears that the pair of hawks we stud- ied were selecting nesting materials that were most readily available but within a given size class, even though this behavior could increase the energy cost of nest construction. In addition we suggest that Great Basin Ferruginous Hawks are substituting rubbish of various types for greenery in the decoration of their nests. A cknowledgment We thank D. M. and L. W. Woffinden for valuable field assistance. The University of Pittsburgh at Johnstown provided financial support. Literature Cited Behle, W. H., A. M. Woodbury, and W. P. Cottam. 1944. Further light on the fossil bird nests of the Great Salt Lake Desert. Proc. Ut. Acad. Arts, Sci. & Letters, 21:23. Bent, A. C. 1937. Life histories of North American birds of prey. (Pt. 1). U.S. Natl Mus. Bull 167:1-409. Brown, L., and D. Amadon. 1968. Eagles, hawks, and falcons of the world. McGraw-Hill Book Co., New York. 4 RAPTOR RESEARCH Vol. 16, No. 1 Haskell, H. S., and H. G. Reynolds. 1947. Growth, developmental food requirements, and breeding activity of the California jackrabbit. J. Mammal. 28:129-136. Imler, R. H. 1937. Weights of some birds of prey of western Kansas. Bird-banding 8:166-169. Lokemoen, J. T., and H. F. Duebbert. 1976. Ferruginous hawk nesting ecology and rap- tor populations in northwestern South Dakota. Condor 78:464-470. Murphy, J. R., F. J. Camenzind, D. G. Smith, and J. B. Weston. 1969. Nesting ecology of raptorial birds in central Utah. Brigham Young U. Sci. Bull., Biol. Ser. 10(4): 1-4. Newton, I. 1979. Population ecology of raptors. Buteo Books, Vermillion, S.D. Olendorff, R. R. 1972. The large birds of prey of the Pawnee National Grassland, U.S.I.B.P. Grassland Biome, technical report No. 151. Smith, D. G., and J. R. Murphy. 1973. Breeding ecology of raptors in the eastern Great Basin of Utah. Brigham Young U. Sci. Bull., Biol. Ser. 28(3): 1-76. Tavener, P. A. 1919. The birds of Red Deer River, Alberta. Auk 36:1-21. Thurow, T. L., C. M. White, R. P. Howard, and J. F. Sullivan. 1980. Raptor ecology of Raft River Valley, Idaho. E. G. & G. Idaho, Inc., Idaho Falls, ID. Weston, J. B. 1969. Nesting ecology of raptorial birds in central Utah. Brigham Young U. Sci. Bull., Biol. Ser. 10(4):25-34. Williams, R. B. and C. P. Matteson. 1947. Wyoming hawks. Wyoming Wildlife 11:38. Woffinden, N. D. 1975. Ecology of the Ferruginous Hawk ( Buteo regalis ) in central Utah: Population dynamics and nest site selection. Unpublished Ph.D. dissertation, Department of Zoology, Brigham Young University, Provo, Utah. A SURVEY OF RAPTORS IN NORTHERN UTAH, 1976-79 by James A. Gessaman Department of Biology Utah State University Logan, Utah 84322 Abstract A roadside survey of raptors was conducted in Cache Valley, Utah during 3 (1976-77, 1977-78, and 1978-79) non-nesting seasons (November to mid-April). The Rough-legged Hawk (Buteo lagopus) was most numerous, followed in abundance by the Red-tailed Hawk (Buteo jamaicensis). Marsh Hawk (Circus cyaneus) and American Kestrel (Falco sparverius). Thirteen other species of raptors were observed. Male Kestrels were 2 to 3 times more abundant than females in December through March. Light phase individuals were 3 to 5 times more numerous than dark phase birds among Red-tailed Hawks and Rough-legged Hawks. Introduction The present study was undertaken to provide information on the relative numbers of raptors during the non-breeding season in Cache Valley, Utah. Surveys of raptors taken over several months from roads can provide information on distribution and seasonal changes in abundance of birds of prey. Raptor Research 16(1):4-10 Spring 1982 Gessaman— Northern Utah Raptor Survey 5 Study Area Cache Valley is bordered on the west by the Wellsville Mountains and Clarkston Mountains and on the south and east by the Bear River Range. The northern boundary of the study area was the Utah-Idaho border (Figure 1). Average elevation of the valley is 1,341 m. The area is a mosaic of agricultural lands (irrigated pasture and hayland, and dry cropland), urban areas, river floodplains, foothills, marshlands and open water. Figure 1.— A map of Cache Valley, Utah showing the 8 census areas included in the raptor survey. 6 RAPTOR RESEARCH Vol. 16, No. 1 Methods About 95% of the total surface area in Cache Valley, Utah was divided into 8 census areas. These 8 areas ranged from 8,080 to 10,664 hectares. The total area censused was 77,024 ha (770.3 km 2 ). The location of each area and its identification number are shown in Figure 1. The area of each habitat type is given in Table 1. Table 1. The surface areas of seven major habitat types within eight census areas in Cache Valley, Utah SURFACE AREA (HECTARES) OF MAJOR HABITAT TYPES IN EACH CENSUS AREA 1 2 3 4 5 6 7 8 Urban Area 157 236 2,788 189 583 677 661 3,182 Irrigated Pasture and Hayland 3,497 8,576 2,928 6,710 7,760 3,750 5,325 6,490 Dry Cropland 4,678 - 772 457 803 - 1,166 992 Native Grazingland 1,528 - 3,355 268 - 2,551 1,967 - Open Water 63 - - 63 457 472' - - River Floodplain - 1,355 - 882 205 - - - Marshland - 64 315 267 630 205 Total Area 9,923 10,231 9,843 8,884 10,075 8,080 9,324 10,664 '189 hectares is an open sewage treatment lagoon Eight censuses of the total area were conducted between November and mid-April over a period of 3 win- ters; 1976-1977 (3 censuses), 1977-1978 (2 censuses), and 1978-1979 (3 censuses). The censuses, except for 20 January 1979, were completed over a period of 2 to 7 days. Usually each area was censused by a different group of observers. The number of observers in each group ranged from 2 to 6 (av. 2.4). The number of ob- servers and total observer hours involved in each of the 8 censuses is reported in Table 2. Each group tried to drive all of the paved and gravel roads in their census area. Sometimes snow made some gravel roads impassable. In addition, ungraveled roads that led to otherwise inaccessible areas were driven when road conditions permitted. The distance driven during each census is shown in Table 2. Mean temperature, precipitation and snow on the ground for each census is given in Table 2. Wind during the censuses was less than 12 km/hr. Censuses were not taken during conditions of snow or rain that impaired visibility. Table 2. A summary of kilometers driven, number of participants, and weather for each raptor census Participants Weather During Census Period Dates of Censuses Month Day(s) Year Total Km Driven Number of Observers Total Observer Hours Temperature (°C) Mean Mean Max Min Snow On Ground (cm) Precipitation (cm) Nov 3-7 1977 933 20 96.1 15.0 0.6 .38 on Nov. 6 Dec 2-8 1978 756 24 101.5 1.7 -7.2 .48 on Dec. 5 Dec 5-10 1976 825 11 - 5.0 -8.3 .20 on Dec. 5 Jan 20 1979 789 16 80.0 -2.2 -10.0 28 Trace Feb 11-18 1978 805 17 75.0 2.2 -7.2 Everyday, total 1.9 Feb 19-23 1977 889 24 128.5 10.6 -3.3 .63 on Feb. 22 March 3-4 1979 686 20 83.5 1.1 -13.3 .66 on March 3 April 9-15 1977 784 18 90.0 17.8 1.1 .69 on April 15 Mean 810 93.5 Spring 1982 Gessaman— Northern Utah Raptor Survey 7 Results and Discussion Relative Abundance Rough-legged Hawks, Red-tailed Hawks, March Hawks and American Kestrels were abundant. Counts of 25 or more /day/ 1,000 km driven were usual for each species, and on average, they comprised 81% of the raptors in Cache Valley (Table 3). None of the raptors was categorized as common although the Prairie Falcon ( Falco mexicanus) was fairly common. An average of 8.1 was observed in the Valley/ 1,000 km driven. A rank- ing of 10 uncommon raptor species (i.e., average counts of less than 4/ census) from the most numerous to the least numerous is shown in Table 3. A few Osprey (. Pandion haliaetus ) migrate through Cache Valley in April on their way to northern nesting grounds. The one observation of a Harris Hawk ( Parabuteo uni- cinctus ) was probably a semi-tame individual released by or escaped from a falconer. It was approachable at close range and was unmistakenly identified. Craig (1978) conducted a car survey over a 187 km route in southeastern Idaho dur- ing non-nesting seasons from November 1974 to May 1976 and found that Rough-legged Hawks were the most numerous, followed in abundance by the American Kestrel and the Golden Eagle (Aquila chrysaetos ) l Seasonal Changes in Abundance The Rough-legged Hawk and Prairie Falcon are winter residents (WR) in Cache Val- ley, but do not nest in the Valley nor in surrounding mountains. In the early March cen- sus, Rough-legged Hawks were still as numerous as in the mid- winter censuses and Prairie Falcons were still present (Table 4). In the mid-April census only 3 Rough- legged Hawks still lingered in the Valley but Prairie Falcons were absent. American Kestrels increased dramatically from March to April as individuals mi- grated into the Valley to establish breeding territories. The Swainson’s Hawk (Buteo swainsoni) appears in April as individuals arrived from their southern wintering grounds. Distribution in the Valley The 4 abundant species were observed in all 8 census areas, but were more abundant in areas 5, 6 and 7 in the central part of the Valley. The Prairie Falcon was the only other species observed in all 8 areas. The average number of individuals observed per census ranged from 0.4 in area 3 to 1.9 in area 5. The Sharp-shinned Hawk (Accipiter striatus) was absent in areas 2 and 8 where 87% and 94%, respectively, of the area is in urban development and irrigated pasture and hayland. The Short-eared Owl (Asio flammeus ) was most numerous in census area 6. They were concentrated along a strip of old field that bordered the east side of the Lo- gan sewage treatment lagoon. The Goshawk (Accipiter gentilis) was observed in the 4 areas that bordered the mountains (areas 1, 3, 7 and 8). Sex and Color Phase Differences From the census data of 3-7 November 1977, 20 January 1979 and 11-18 February 1978 where the color phase was identified for at least 75% of the birds observed, light 'Ed. Note: Several people who have done similar roadside counts suggest one should use caution in using data from different years to show changes in seasonal abundance. MEAN NUMBERS OF BIRDS OBSERVED PER CENSUS' IN EACH CENSUS AREA RAPTOR RESEARCH Vol. 16, No. 1 U C £H S § Q go | a s f® ns 3 ^ 1 'H'tflO©O>''ta0CD cO oQkOodcDi— !o>ioco oi co to Tf cq COOOONCDt'O o^roG^c^t^Trc-i PC £ N CD CO C b O! O CO O O i-h O © O O HoioioidHod © © © © © © © d tj o- 1« s ,2 cj -t- a - 2 -1 I- t O I l Z w « H 03 O - t>o5edidc3ii-5c cm in eg t-i •NHegcoincorrcMHMrtOH ( H T# « —I K 3 _ £ i £ o * ^ g o « -g I l J 7 ^ B rt , 9 £ !l W O "So^ id ¥ S U * ^ o o™ s® 2 j® "9 ^ J= 9 8 4 $ is I if 1 2 u . CD .£ __ 1 ‘ t; ■* cS O B E-i 10 RAPTOR RESEARCH Vol. 16, No. 1 phase was more common than dark phase among both Red-tailed and Rough- legged Hawks. For Red-tailed Hawks 22 were dark phase, 116 were light phase and the color phase of 19 was not identified. Among Rough-legged Hawks 23 were dark phase, 76 were light phase and the color phase of 30 was not identified. Acknowledgments I thank the following people for helping with censuses: Keith Archibald, Lloyd Ben- nett, Kathryn Denne, Keith Dixon, Kathryn Fite, Ann Gessaman, Anthony Graves, Steve Hayes, Lucinda Haggas, Steve Hoffman, Lee Jones, John Kirkley, Peter Landres, Sue Linner, Tom Lyons, Jan Lyons, Mary Murphy, Antoinette Pepin, Wayne Potts, Mark Riesataris, Gary Ritchison, Joseph Russin, Ron Ryel, Steve Shope, Kim Smith, Tex Sor- dahl, Mark Stalmaster, Ben Steele, Steve Vander Wall, Rick Vetter, Gene Washington, Mary Washington, and Eric Zurcher. Literature Cited Craig, T. H. 1978. A car survey of raptors in southeastern Idaho 1974-1976. Raptor Res. 12:40-45. WINTER ROADSIDE RAPTOR SURVEY IN EL PASO COUNTY, COLORADO, 1962-1979 by Elizabeth N. Bauer 2S60 N. Park Avenue Tucson, Arizona 85719 Abstract A fixed-route car survey was conducted from October to February 1979-80 on a 103- km strip of predominantly rangeland east of Colorado Springs, Colorado. Comparison of these data with past relative density data from 1962-1979 shows fairly steady numbers for 7 of the 8 species. Rough-legged Hawks showed a slight decline. Most raptors were seen perched on REA poles. Cropland was used most by all species considering its avail- ability to the area. Introduction Car surveys are a convenient method for sampling raptor populations which are con- spicuous yet thinly distributed over large areas. Previous car surveys on rangeland in eastern Colorado have been conducted showing estimates of raptor abundance (Ender- son 1965, Johnson and Enderson 1972, unpublished data) and behavioral data of perch- site preference (Marion and Ryder 1974, Stahlecker 1978). The purpose of this study was to compare relative abundance and behavioral patterns with past data to investigate possible trends. Perch-site preference could be important in management of raptors on rangeland. Materials and Methods The 166 km 2 area about 12 km east of Colorado Springs, Colorado is a 103-km circuitous strip 1.6 km wide. It is predominantly (90.9%) rangeland comprised mainly of blue gramma ( Bouteloua gracilis ) and sandhill Raptor Research 16(1): 10-13 Spring 1982 Bauer— Roadside Raptor Survey 11 bluestem (Andropogon hallii). The remainder is 4.0% cropland (primarily winter wheat, Triticum anetivum), 3.5% residential (where most trees occur), and 1.6% cottonwood ( Populus sargentii) and willow (S alix exigua) riverbottom. The lack of tall vegetation makes the prairie ideal for spotting large birds at great distances. Fenceposts are predominant perches available to raptors, running along both sides of almost the entire road and spaced about 5 m apart. Next are Rural Electrification Administration (REA) poles usually occurring along one side of the route about 0.1 km apart. Other potential perches include windmills, trees, large trans- mission line towers, and irrigation sprinkler towers (about 3.5 m high). Censuses began 4 October 1979 and ended 1 February 1980. Thirty-one counts, totalling 3,194 km, were made between 3 and 6 h at a rate averaging 48 km/h. Fourteen surveys were made in October, 4 in Novem- ber, 7 in December, 5 in January and 1 in February. All days of censusing were clear to partly cloudy and with winds no greater than 15 knots. Species, location, activity and sex (when possible) of raptors seen were recorded. I tried to avoid recording the same bird twice by noting the direction it flew. Because I was both driving and observing, my sightings were necessarily biased to the vicinity of the road. However, the roads traveled were virtually traffic free and because I made a conscious effort to scan the sky, the results are not strongly biased to perching birds. Results and Discussion In all, 358 raptors of 8 species were seen. Most birds were perched (87%) (Table 1), Table 1. Perching of raptors on 103-km route, Colorado, 1979-80 Species flying or soaring REA poles fence posts Number of observations (percent) ground wire power poles other total seen Red-tailed Hawk 2 21 1 4 - - 7 35 (Buteo jamaicensis ) (60) (11) (20) Rough-legged Hawk 11 35 8 4 - - 12 70 ( Buteo lagopus) (16) (50) (11) (17) Ferruginous Hawk 7 25 6 3 - 1 5 47 (Buteo regalis ) (15) (53) (13) (11) Golden Eagle 11 19 3 2 - 3 11 49 (Aquila chrysaetos ) (22) (39) (22) Marsh Hawk 17 4 3 11 - - - 35 (Circus cyaneus ) (49) (11) (31) Prairie Falcon 8 44 5 1 1 2 1 62 (Falco mexicanus ) (13) (70) American Kestrel 5 11 7 - 30 - 5 58 (Falco sparverius ) (19) (12) (52) Merlin 2 1 3 contrary to the findings of Marion and Ryder (1974), but in agreement with those of Craig (1978). Roadside REA poles were the most common perch for all species except the Golden Eagle (Aquila chrysaetos). Marsh Hawk ( Circus cyaneus) and American Kes- trel (Falco sparverius). Stahlecker (1978) found a significant usage of 230kV transmission line towers in areas where they occur. I saw only 8 raptors, mostly Golden Eagles, on these towers even though I gave particular attention to them. A seasonal change in abundance was noticed for 7 species in the study area (Table 2). The Red-tailed Hawk ( Buteo jamaicensis ) was seen in October but completely left the area by December. Of 35 recorded, 32 were identified as mature, 3 immature. The Fer- ruginous Hawk ( Buteo regalis) was common in October and then decreased to a fairly 12 RAPTOR RESEARCH Vol. 16, No. 1 Table 2. Raptors seen per month on the 103-km route October November December January Species no. seen birds 100 km no. seen birds 100 km no. seen birds 100 km no. seen birds 100 km Red-tailed Hawk 29 2.2 2 .32 - - - - Rough-legged Hawk 14 1.0 . 8 1.3 16 2.6 31 5.0 Ferruginous Hawk 26 1.9 4 .65 4 .65 6 .97 Golden Eagle 15 1.1 6 .97 8 1.3 14 2.3 Marsh Hawk 17 1.3 4 .65 5 .81 6 .97 Prairie Falcon 34 2.5 14 2.3 6 .97 8 1.3 Kestrel 41 3.1 8 1.3 5 .81 4 .65 Merlin - - - - 1 .16 2 .32 km per month 1,340 618 618 618 ’Total number of raptors seen is less than in Table 1 due to the omittance of data taken on days of variable weather. constant number throughout the remaining months. These 2 species of hawks apparently migrate through the plains in October. The Rough-legged Hawk ( Buteo lagopus) was the most common winter raptor; their population increased as winter progressed. Golden Eagle population was steady until January when there was a noticeable increase. Of 49 sightings, 21 were identified as mature, 17 immature. Marsh Hawks dropped in number after October. Of the 35 individuals seen, 23 were identified as males and 10 as females. The Prairie Falcon ( Falco mexicanus) was common the first 2 months, but decreased in numbers in December and January. Of 62 seen, 25 were identified as adults, 8 imma- ture, 14 males and 20 females. American Kestrels, most abundant in October in migra- tion, showed a decrease in numbers throughout the winter. Of 58 seen, 38 were identi- fied as males and 10 as females. Only 3 sightings of the Merlin ( Falco columbarius) occurred. Relative to its availability, cropland was the favored habitat (Table 3). Wakely (1978) found a preference by Ferruginous Hawks for areas dependent upon the amount of veg- etational cover rather than on prey densities. Similarly, I found Ferruginous Hawks only in open areas of low vegetation density (pasture and cropland). Open areas appeared to be favored by Rough-legged Hawks, Golden Eagles and Prairie Falcons. Red- tailed Hawks, Marsh Hawks and Kestrels were found in a variety of areas. Table 3. Percentage of times raptors seen in habitats to the total times seen Habitats (percent of the area to the total roadside area) Species Pasture (90.9) Cottonwood/ willow (1.6) Residences/ trees (3.5) Cropland (4.0) Red-tailed Hawk 71.4 8.6 5.7 14.3 Rough -legged Hawk 84.8 1.3 1.3 12.6 Ferruginous Hawk 78.8 - - 21.2 Golden Eagle 83.7 - - 16.3 Marsh Hawk 65.7 5.7 5.7 22.9 Prairie Falcon 76.2 - - 23.8 Kestrel 77.6 1.7 3.5 17.2 Spring 1982 Bauer— Roadside Raptor Survey 13 Raptors seen/ 100 km traveled in earlier studies in the same area have been compiled by two-year periods to obtain a significant number of kilometers, in each time period (Table 4). The data are subject to biases because of variations in methods used. The ma- jority of censuses were made by one observer, routes were fairly similar to mine and were made in winter on clear days. Table 4. Raptors (individuals/km) recorded in car censuses in El Paso County, Colorado, 1962-80 Species 62-64 69-70 71-72 72-74 74-76 76-78 78-80 Red-tailed Hawk .15 1.8 6.8(h) 1.5 3.8 1.6 Rough-legged Hawk 6.9 6.1 2.6 3.9 5.5 2.5(1) Ferruginous Hawk .55 1.3 .26(1) 2.1 2.8(h) 1.4 Golden Eagle 1.2 2.7(h) .52 2.5 .69 1.4 Marsh Hawk 2.8 1.6 .52(1) 1.8 4.5(h) 1.4 Prairie Falcon 2.3 2.1 1.3(1) 2.8 5.2(h) 1.9 Kestrel 1.2(1) 3.0 3.6 3.5 4.1(h) 2.5 Merlin .33 .38 - .38 .35 .08(1) Total kilometers 674 782 386 1,065 290 3,540 Values are marked high (h) or low (1) if they vary significantly by t-test analysis for a 90% confidence interval using data from all years per species. Past data from published works of Enderson (1965), Johnson and Enderson (1972) and unpublished works of Enderson, R. Beidleman, J. Craig, P. Kennedy and B. Winternitz. Merlins have the lowest density figures. Density was steady from 1962 until the last two-year period of 1978-80 when they reached a low. Prairie Falcons and Kestrels show fairly low variation in numbers throughout the years if the data for 1972-74 and 1976-78 periods are discounted because of the low numbers of kilometers traveled in these periods. In fact, these periods show most of the significant deviation. In view of this variation the populations of hawks and eagles appear steady throughout the years. The Rough-legged Hawk is an exception and showed a decrease (disregarding the two low mileage periods). Acknowledgments I thank J. Craig, P. Kennedy, R. Beidleman, J. H. Enderson and B. Winternitz for un- published data. I also thank J. H. Enderson and B. Winternitz for criticism of previous drafts. Literature Cited Craig, T. 1978. A car survey of raptors in southeastern Idaho, 1974-76. Raptor Res. 12:40-45. Enderson, J. H. 1965. Roadside raptor count in Colorado. Wilson Bull. 77:82-83. Johnson, D. and J. H. Enderson. 1972. Roadside raptor census in Colorado— winter 1971-72. Wilson Bull. 84:489-90. Marion, W. R. and R. A. Ryder. 1975. Perch-site preferences of four diurnal raptors in northeastern Colorado. Condor 77 :350-352. Stahlecker, D. W. 1978. Effect of a new transmission line on wintering prairie raptors. Condor 80:444-446. Wakely, J. S, 1978. Factors affecting the use of hunting sites by Ferruginous hawks. Condor 80: 316-326. HELPING AT THE NEST BY YEARLING MISSISSIPPI KITES by James W. Parker Biology Department University of Maine Farmington, Maine 04938 and Mark Ports Department of Biological Sciences Fort Hays State University Hays, Kansas 67601 Abstract Helping at the nest by a yearling Mississippi Kite ( Ictinia mississippiensis ) was con- firmed at 3 nests and strongly indicated at 15 others from nests studied during 1969-79. Helpers incubated, brooded and, most frequently, defended nests. For this species we believe that nest defense is a significant form of helping because predation on nests is a major source of mortality. Circumstantial evidence suggests that helping increases nest success and possibly benefits helpers, but more study is needed. Introduction Cooperative breeding is uncommon in raptors (Skutch 1961, Rowley 1976, Wiley 1975, Wegner 1976). It appears regular, in the form of polyandry, in only two species of falconiformes, the Galapagos Hawk ( Buteo galapagoensis, Vries 1973, Faaborg et al. 1980) and the Harris’ Hawk ( Parabuteo unicinctus, Mader 1975, 1979). Here we present the first evidence of helping at the nest by Mississippi Kites, a locally common, often co- lonial species undergoing a major population expansion in the United States (Parker and Ogden 1979). Methods and Study Areas Ports intermittently observed a nest from a nearby blind for 20 hr from 8 to 26 June, 1976 in Woodland Park, a suburban area in Oklahoma City, Oklahoma. Parker made incidental observations during repeated vis- its to about 900 Mississippi Kite nests at 55 breeding colonies in western Kansas, Oklahoma and north-central Texas during 1968-73 and 1976-79 (Parker 1974, unpubl. data). Most colonies were in shelterbelts (wind- breaks) or similar vegetation. All or most kites in most colonies were observed simultaneously during flocking, but conclusive identification of 2 or more kites at a nest was made only for 209 nests. Observations (i.e., of nesting behaviors, size and plumage color) and banding experience with kites enabled us to sex adult kites if they were seen repeatedly or together. Adult males are lighter and smaller than females (Sutton 1944, Eisen- mann 1963, Brown and Amadon 1968), and although the characters overlap, the two in combination are usu- ally conclusive. Yearlings differ from adults by their barred rectrices and the occasional juvenal contour feath- ers on the abdomen, breast and wing linings. The sex of yearlings is difficult to determine unless a careful size comparison can be made. Results Yearling kites were present at about half the colonies studied by Parker. Although not all yearlings bred, most adults did. Yearlings were present at 52 of the 209 nests where 14 Raptor Research 16(1): 14-17 Spring 1982 Parker and Ports— Nest Helping 15 all kites were identified. A yearling appeared pair bonded to an adult for at least 35 (17%) of the 209 nests. At 2 other nests, a yearling helped an adult pair by incubating, brooding, or defending the nest against potential predators. Observations at 15 other nests suggested a similar alloparental yearling helper. The kites’ behavior at 2 nests with confirmed helpers is of greatest interest. The nest observed by Ports was attended by an adult male, an adult female and a large yearling female. During the first observation period, the 2 adults were perched near the nest and allowed the yearling to approach the nest, arrange nesting material, and incubate one egg for at least 90 min. The yearling incubated 2 eggs for 74 min. during the next obser- vation period 5 days later and then sat alone near the nest for 90 min. Fifteen days later (the fourth observation period), the yearling perched near the nest for a minimum of 3V2 hr while the adult female incubated. On one occasion, the adult male replaced the year- ling on the nest. The yearling did about 15% of the observed incubation (164 of 1100 min.), the adult female about 84%, and the male very little. Two adult kites were present during 6 of Parker’s 11 visits to another nest in a short, lone black locust ( Robinia pseudoacacia ) about 13 km north of Englewood, Clark Co., Kansas. On 29 June, 1979 during the third visit to the nest, a yearling was frightened from this nest containing one egg and one very small nestling. No adults were present, and the yearling left the nest area as adults sometimes do when disturbed. The yearling was next and last seen near the nest on 6 July when it perched with one adult while the other soared nearby. At the 15 nests where a helper was suspected, yearlings were often seen with 2 adults. At these nests yearlings were not observed to incubate or brood, but this was probably the result of inadequate observations because yearlings often perched at or near nests, were as disturbed by our presence as were the paired adults, and showed more alarm than other adults nesting nearby in the same colony. Typically the yearlings soared with 2 adults low over us and the nest, occasionally made low passes, and sometimes uttered alarm calls. They did not behave this way when we visited other nearby nests. In 1971 in a mesquite grove near Jones County, Texas, 2 adults fledged 2 young at a nest where helping could not be confirmed except in terms of nest defense. During our last visit, a yearling was seen at the nest with one full-grown nestling. In 1972, this same nest (probably the same 2 adults based on Parker’s experience with reuse of nests by kites) produced 2 fledglings. On 1 August 1972, 2 yearlings and 2 adults were present and all showed equal alarm and defense behavior when the fledglings were approached. Twice later a fledgling was seen flying with one yearling. At no nests, including the pre- ceding, did adult kites show any aggression toward yearlings. Discussion Observations by other workers suggest that yearling Mississippi Kites help at nests (Seibel 1971, pers. comm, for Kansas, R. Glinski and R. Ohmart pers. comm, for Ari- zona). Hardin et al. (1977) observed yearlings with each of 4 breeding pairs of adults in southern Illinois, and S. Evans (pers. comm.) made similar observations at each of 6 ac- tive nests in the same population in 1980. Our observations are the first to confirm the existence of helping in the forms of incubation, brooding of nestlings, and nest defense. Whether or not helping is frequent is uncertain, but nest defense was the most observed form of helping by yearlings. Nest defense is frequently important in other species with helpers (Wilson 1975, Lack 1968, Brown 1978). For instance, predation is a major prob- lem for the Florida Scrub Jay (Aphelocoma coerulescens ), one of the most thoroughly 16 RAPTOR RESEARCH Vol. 16, No. 1 studied cooperative nesters (Stallcup and Woolfenden 1978, Woolfenden and Fitz- patrick 1978). This also seems true of the Mississippi Kite. Its predators, especially other raptors and large climbing mammals, kill adults on nests as well as many eggs and nest- lings (Parker 1974, unpublished data). It is reasonable, then, that increased vigilance and nest defense against nest predators might represent a significant benefit and probably in- creased nest success. We believe the repeated presence of a yearling kite near a nest of 2 adults can be interpreted as a form of helping when the yearling defends the nest against predators. In only a few bird species is helping actually shown to increase nest success (Rowley 1965, Woolfenden 1975, Brown 1978). Indeed, this is so for the Harris’ Hawk (Mader 1979, 785). Our data, although circumstantial, suggest the same for the Mississippi Kite. Thirteen (72%) of the 18 nests with attendant yearlings raised at least one nestling to fledging age. This is significantly greater (PC.05, t-test comparing arcsin transforma- tions of percentages) than a 48% nest success for 396 nests in 1969-1971 (Parker 1974) at which no helpers were detected. A possible bias is that 3 of the 18 were lone nests, and lone kite nests are statistically more successful than nests in colonies (Parker 1974). However, it seems unlikely that this could account for the considerable difference in success rates. Fry (1972), Woolfenden and Fitzpatrick (1978) and Brown (1978) stressed that helpers may benefit from helping by learning and improving behaviors they will use in the fu- ture. Woolfenden (1975) demonstrated the benefits of helping for male Scrub Jay help- ers, and Brown (1978) noted that for colonial species there seem to be few selective ad- vantages for helpers except the acquisition of experience in the breeding situation. A helper kite would probably accept a minimal risk for its minor effort compared to the risks experienced by breeding adults, but it might enhance its familiarity with specific nesting and foraging areas, the locations and behaviors of predators, and adaptive re- sponses to predators. Curio et al. (1978) showed that inexperienced European Blackbirds (' Turdus merula ) quickly learned to recognize and mob avian predators after observing mobbing of the predators by experienced blackbirds. This strongly supports the hypoth- esis that kite helpers benefit from association with breeding adults by observation of the adults’ adaptive behaviors. It is not surprising that the Mississippi Kites in the Great Plains exhibit nest helping because they show many characteristics often associated with group-breeding species (Woolfenden and Fitzpatrick 1978, Brown 1978, Wilson 1975, Fry 1972). They live in stable, small and somewhat isolated units and often forage in groups on patchily- distributed insects. They show relatively little sexual dimorphism (Snyder and Wiley 1976) and have a low reproductive rate coupled with a long life expectancy (Parker 1974). Their sex ratio apparently favors males 1.4 to 1 based on a sample of 120 adult specimens collected from throughout the species’ breeding range. The kites’ nesting en- vironment is hot combining predictable elements, such as abundant nesting habitat, and unpredictable elements, such as local predation rates, the occurrence of storms, and in- sect food. In general its life history suggests a K-strategy. Clearly, additional detailed study at individual nests is needed before helping by yearling Mississippi Kites can be understood. We thank W. Mader, J. Faaborg, J. Grier, K. Meyer and N. Synder for suggestions on early drafts of the manuscript. We also thank Jane and Douglas Parker and a number of students for field assistance. Parker received financial aid from an NSF Traineeship at Spring 1982 Parker and Ports— Nest Helping 17 the University of Kansas, the State University of NY Research Foundation, the Frank M. Chapman Memorial Fund, the Eastern Bird-Banding Association, the Kansas Academy of Sciences, and the Environmental Resources Center at Fredonia College. The Kansas Fish and Game Commission provided living quarters and other aid. Literature Cited Brown, J. 1978. Avian communal breeding systems. Ann. Rev. Ecol. Syst. 9:123-155. Brown, L. and D. Amadon. 1968. Eagles, hawks and falcons of the world. Vol. 2. McGraw-Hill, New York. Curio, E. U. Ernst and W. Vieth. 1978. The adaptive significance of avian mobbing. II. Cultural transmission of enemy recognition in blackbirds: effectiveness and some constraints. Z. Tierpsychol. 48:184-202. Eisenmann, E. 1963. Mississippi kite in Argentina; with comments on migration and plumages in the genus Ictinia. Auk 80:74-77. Faaborg, J., Tj de Vries, C. B. Patterson and C. R. Griffin. 1980. Preliminary observa- tions on the occurrence and evolution of polyandry in the Galapagos Hawk ( Buteo galapagoensis). Auk 93:581-590. Fry, C. H. 1972. The social organization of Bee-eaters (Meropidae) and cooperative breeding in hot-climate birds. Ibis 114:1-14. Hardin, M. E., J. W. Hardin and W. D. Klimstra. 1977. Observations of nesting Mis- sissippi kites in southern Illinois. Trans. III. State Acad. Sci. 70:341-348. Lack, D. 1968. Ecological adaptations for breeding in birds. Methuen, London. Mader, W. J. 1975. Extra adults at Harris’ hawk nests. Condor 77:482-485. Mader, W. J. 1979. Breeding behavior of a polyandrous trio of Harris’ hawks in southern Arizona. Auk 96:776-788. Parker, J. W. 1974. The breeding biology of the Mississippi kite in the Great Plains. Ph.D. dissertation. Univ. Kansas, Lawrence. Parker, J. W. and J. C. Ogden. 1979. The recent history and status of the Mississippi kite. Amer. Birds 33:119-129. Rowley, I. (Convener). 1976. Cooperative breeding in birds. Symposium No. 10. Proc. 16th Int. Ornithol. Congr. Australian Acad. Science, Canberra. Scutch, A. F. 1961. Helpers among birds. Condor 63:198-226. Seibel, D. 1971. The Mississippi kite. Ks. Ornithol. Soc. Bull. 22:6-7. Snyder, N. F. R. and J. W. Wiley. 1976. Sexual size dimorphism in hawks and owls of North America. Ornithol. Monogr. 20:1-96. Stallcup, J. A. and G. E. Woolfenden. 1978. Family status and contributions to breeding by Florida scrub jays. Animal Behav. 26:1144-1156. Sutton, G. M. 1944. The kites of the genus Ictinia. Wilson Bull. 56:3-8. Vries, Tj. de. 1973. The Galapagos Hawk: an eco-geographical study with special refer- ence to its systematic position. Free University Press, Amsterdam, Netherlands. Wegner, W. A. 1976. Extra-parental assistance by male American kestrel. Wilson Bull. 88:670. Wiley, J. M. 1975. Three adult Red- tailed hawks tending a nest. Condor 77:480-482. Wilson, E. O. 1975. Sociobiology: The new synthesis. Harvard University Press, Cam- bridge, MA. Woolfenden, G. E. 1975. Florida scrub jay helpers at the nest. Auk 92:1-15. Woolfenden, G. E. and J. W. Fitzpatrick. 1978. The inheritance of territory in group- breeding birds. Bioscience 28:104-108. BREEDING BIOLOGY OF RAPTORS IN THE CENTRAL APPALACHIANS by Cynthia A. Janik and James A. Mosher Appalachian Environmental Laboratory University of Maryland Frostburg, Maryland 21532 Abstract We have summarized the breeding chronology, productivity and food habits of the principal diurnal raptors of the Central Appalachian region from 1978-1980. Nest suc- cess varied from 53% for Red-shouldered (Buteo lineatus) to 86% for Broad-winged (Buteo platypterus) hawks. The average number of young fledged per nest attempt was 1.4, 1.8, 1.7 and 2.0 for Red-tailed ( Buteo jamaicensis), Red-shouldered, Broad-winged and Cooper’s Hawks (Accipiter cooperi), respectively. The principal prey species for this raptor community is die eastern chipmunk. Introduction Recent declines of a few raptor species demonstrate their sensitivity to ecosystem per- turbations and the need for substantial baseline data. Little research on raptor populations has been conducted in the Appalachian region. Studies of the breeding biology of populations provide data important for monitoring the future status of these populations and for establishing population norms against which effects of environmental changes may be assessed. In this study, nesting Broad- winged (Buteo platypterus ), Red-tailed (B. jamaicensis). Red-shouldered (B. lineatus ) and Cooper’s (Accipiter cooperi) hawks were studied to determine the status of the raptor community in the central Appalachian region and to describe their nesting biology, chronology and food habits. Study Area and Methods Ground surveys for nests were conducted on two principal areas: Green Ridge State Forest and Savage River State Forest (Figure 1). Green Ridge State Forest, in eastern Allegany County, encompasses 10,522 ha (26,000 acres) of woodland ranging in eleva- tion from 340 to 485 meters. Tree species include oak (Quercus spp.), ash (Fraxinus spp.), maple (Acer spp.) and hickory (Carya spp.). In bottom sites, white pine (Pinus strobus ), poplar (Populus spp.) and mountain ash (Sorbus americana) are present. Some forest areas formerly converted to orchard plots now support Virginia pine (Pinus virgi- niana), pitch pine (P. rigida ), short leaf pine (P. echinata) and table pine (P. pungens). Savage River State Forest, in central and eastern Garrett County, totals 21,355 ha (52,770 acres) and ranges from 454 meters on the Savage River to 912 meters. Pre- dominant vegetation is wild cherry (Prunus serotina), red (Acer rubrum) and sugar maple (A. saccharum ), black (Betula lenta) and yellow birch (B. lutea), beech (Fagus grandi- folia ), basswood ( Tilia americana), white pine and hemlock (Tsuga canadensis). Oak, tu- lip poplar (Liriodendron tulipifera) and hickory are characteristic trees of lower elevations. 18 Raptor Research 16(1): 18-24 Spring 1982 Janik and Mosher— Central Appalachian Raptors 19 Sections of both areas were systematically searched for stick nests during the 1978, 1979 and 1980 breeding seasons. Intensive searches were concentrated in February, March and April when breeding birds arrived and continued through leafing out of the trees. Vocalizations, aerial displays and sighting frequency were used to aid in locating nests. All nests were plotted on l l A min U.S.G.S, maps. Nests were checked periodically for activity during each spring. Active nests were checked prior to egg hatching and during the first week thereafter to obtain clutch and brood sizes. Nest success was deter- mined about the time of fledging. Several nests were observed from ground blinds prior to hatching. During the first week after hatching, tree blinds were constructed 20 to 30 meters away at selected nests of each species for intensive observation with a 15-60X spotting scope. Food habits were determined by observations of items brought to nests and from regurgitated castings found in or near nests. Castings were dissected following the meth- ods of Mathiak (1938), Williams (1938) and Stickel (pers. comm.). Results and Discussion Breeding Population Eighty-four active raptor nests were located in western Maryland during three breed- ing seasons. Nineteen were used by Red-tailed Hawks, 17 by Red-shouldered Hawks, 36 20 RAPTOR RESEARCH Vol. 16, No. 1 Table 1. Raptor breeding activity and productivity in the Central Appalachians 1978-1980. Red- tailed Hawk Red- shouldered Hawk Broad- winged Hawk Cooper’s Hawk Number of active nests' 15 17 36 11 Number of successful nests 10 (67) 2 9 (53) 31 (86) 9 (82) Clutch size 2 (1)' 3.1(6) 2.7(15) 3.6(8) Average number hatched 1.8(12)' 2.4(8) 2.1(29) 2.9(9) Average number fledged 1.4(14)’ 1.8(10) 1.7(34) 2.0(11) ‘Includes only those active nests for which the outcome was known, i.e., failed or fledged some number of young. -Percent of active nests that fledged at least one young. ‘Number of nests which contribute to the mean values. by Broad- winged Hawks and 12 by Cooper’s Hawks. Table 1 includes a summary of ac- tivity and productivity for those active nests for which the outcome was known. Nesting Chronology Nesting chronology is presented in Table 2. The dates presented are generally con- sistent with those previously published for each species (Burns 1911, Bent 1937, Stewart 1949, Hagar 1957, Rusch and Doerr 1972, Henny et al. 1973, Matray 1974, Portnoy and Dodge 1979). Cooper’s Hawks were by far the most variable in the timing of their breeding cycle, with 28 days between the earliest and latest hatching dates for the three years. Nest Success and Productivity Raptor reproduction parameters are summarized in Table 1. Of 15 Red-tailed Hawk nests, 67% successfully fledged young. Nestling mortality was greatest during the second and third week after hatching, attributed to inclement weather and predation by Great Horned Owls. A total of 22 nestlings were produced averaging 1.8 young per active nest and 1.4 fledged. This compares to 66% nest success and 1.35 young per nest attempt de- rived from literature sources reporting a total of 930 nests (Fitch et al. 1946, Orians and Kulhman 1956, Hagar 1957, Roosa 1964, Harris 1971, Luttich et al. 1971, Seidensticker and Reynolds 1971, Gates 1972, Smith and Murphy 1973, Johnson 1973, Wiley 1975, Bohm 1978, Howell et al. 1978, Mader 1978, Adamcik et al. 1979 and Bednarz 1979). Henny and Wight (1972) estimated that the northern Red-tailed Hawk populations must produce between 1.33 and 1.38 young per breeding attempt to maintain a stable population. Of 17 Red-shouldered Hawk nests, 53% fledged young. Eggs from two nests were found crushed, and a third nest contained two addled eggs. Reasons for these failures cannot be determined. Human activity was determined to be a principal cause of Red- shoulder nest failure in California (Wiley 1975). Henny et al. (1973) found the most crit- ical period for nestlings to be the first two weeks post hatching which is between late April and early May. A majority of the nestling mortalities in our study occurred during the first three weeks and in most cases involved the smallest nestling of the brood. Spring 1982 Janik and Mosher— Central Appalachian Raptors 21 Mean clutch size was 3.1 with 1.8 young fledged per nest attempt. This compares to 1.7 young per nest attempt and 2.3 young per successful nest derived from literature sources (Craighead and Craighead 1956, Henny et al. 1973, Portnoy and Dodge 1979, Campbell 1975, Wiley 1975 and Bednarz 1979.) Thirty-one of 36 Broad-winged hawk nests (86%) successfully produced young. Fifty- nine successfully fledged, averaging 1.7 per active nest (see Table 1). Nestling mortality for Broad-winged hawks was also greatest during the first three weeks. Of the 11 Cooper’s hawk nests, nine (82%) produced young. Twenty-six fledged, aver- aging 2.0 young per active nest. The number of Cooper’s hawks to fledge per nest at- tempt in Maryland is about the same as that observed in Michigan (Craighead and Craighead 1956) and in Oregon (Reynolds and Wight 1978), but substantially higher than that observed by Hennessy (1978) in Utah. Table 2. Raptor breeding chronology in the Central Appalachians 1978-1980 1 . Egg Laying Hatching Fledging Red-tailed Hawk - 0 - 4/27(11) 6/9 (3) 4/18-5/7 6/7-6/10 Red-shouldered Hawk - 0 - 5/7 (7) 6/16 (5) 4/22-5/18 6/13-6/20 Broad-winged Hawk 5/1 (1) 6/10(31) 7/13 (13) 5/27-6/20 7/6-7/24 Cooper’s Hawk 5/4 (1) 6/19(7) 7/18 (5) 6/7-7/5 7/2-7/19 'Values given are the mean dates (sample size) over the range. Only nests for which these dates are known to be accurate within 1-2 days are included in the table. Food Habits We studied food habits in 1978 and 1979. For all species, mammals comprised the largest portion of the hawks’ diet (Table 3). The eastern chipmunk ( Tamias striatus) oc- curred most frequently in the diet of Cooper’s, Red-shouldered and Broad-winged Hawks. Juvenile fox squirrel ( Sciurus niger) comprised a major portion of the Red-tailed Hawk diet as determined through pellet analyses. We observed 57 items delivered to nests by adult Cooper’s Hawks 70% mammals and 30% small birds. This is quite different from the diet determined for Cooper’s Hawks in New York and Pennsylvania (Meng 1959) in which avian species comprised a major por- tion of the diet. However, small numbers of avian species were also reported by Fitch et al. (1946) in California but in that study, lizards made up a majority of the food items. Twenty-nine food deliveries were observed at Red-shouldered Hawk nests 79% mam- mals, 14% amphibians (frogs and salamanders) and 6.9% reptiles. This is similar to the food habits of Red-shoulders found in Massachusetts (Portnoy and Dodge 1979). A total of 31 items were brought to nests by adult Broad- winged Hawks, 52% mam- mal, 10% birds and 6% reptiles. These proportions are similar to those found by Rusch and Doerr (1972) in Alberta and by Mosher and Matray (1974) in New York. Small mammal activity patterns were being monitored on the same principal study areas during the two breeding seasons. Results from this study (Ladino 1980) show an early summer peak in activity of small mammals, particularly the eastern chipmunk and 22 RAPTOR RESEARCH Vol. 16, No. 1 Table 3. Food habits of raptors in the Central Appalachians 1978-1979'. Cooper's Hawk Broad-winged Red-shouldered Red-tailed Hawk Hawk Hawk PREY ITEM Observ. Pellet Observ. Pellet Observ, Pellet Observ. Pellet Mammal Tamias striatus 28 3 6 18 11 4 3 Microtus sp. 2 3 6 2 2 1 Peromyscus sp. 1 1 4 Blarina brevicauda 1 2 7 1 3 Sylvilagus floridanus Cleithrionomys gapperi 2 1 3 1 Parascalops breweri Tamias hudsonicus S ciurus niger 1 1 3 6 Sciurus carolenensis Soricidae sp. Unidentified 9 4 4 3 1 1 Total (%f 40 (70) 6(46) 16 (52) 35 (61) 23 (79) 10 (67) 15 (94) Cooper’s Hawk Broad-wit iged Red-shouldered Red-tailed Hawk Hawk Hawk PREY ITEM Observ. Pellet Observ. Pellet Observ. Pellet Observ. Pellet Avian Bonasa umbellus Meliagris galhparo 1 2 2 1 Colaptes auratus 2 Pipilo erythrophthalmus Dryocopus pileatus 1 1 Unidentified 16 7 1 10 1 Total 17 (30) 7(54) 3(10) 15 (26) 1 2(13) 1(6) Reptile Thamnophis sirtolis Unidentified 2 5 2 3 Total 2(6) 5(9) 2(7) 3 (20) Cooper’s Hawk Broad-winged Red-shouldered Red-tailed Hawk Hawk Hawk PREY ITEM Observ. Pellet Observ. Pellet Observ. Pellet Observ. Pellet Amphibian Unidentified frog - 0 - - 0 - - 0 - - 0 - 3 - 0 - - 0 - - 0 - Unidentified salamander - 0 - - 0 - - 0 - - 0 - 1 - 0 - - 0 - - 0 - Total - 0 - - 0 - - 0 - - 0 - 4(14) ,0- - 0 - - 0 - Miscellaneous Coleoptera - 0 - 1 - 0 - - 0 - - 0 - - 0 - Snail - 0 - 1 - 0 - - 0 - - 0 - - 0 - Unidentified 10 - 0 - - 0 - - 0 - - 0 - - 0 - Total - 0 - - 0 - 10 (32) 2(4) - 0 - - 0 - - 0 - - 0 - 'As determined by nest observation and analysis of casting. -Percent of total diet by observation or pellet analysis. Spring 1982 Janik and Mosher— Central Appalachian Raptors 23 white-footed mouse (Peromyscus leucopus) in June and July for 1978 and 1979. The fre- quency of hawk predation on these species may be related to their abundance and avail- ability at this particular time of year. Acknowledgments We wish to thank the following individuals for their assistance in various aspects of this field research: D. Lyons, F. Presley, M. Presley and K. Titus. This research was sup- ported in part by contracts with the U.S. Fish and Wildlife Service (FWS 14-16-0009- 77-960 and 14-16-0009-80-007). This is Contribution Number AEL-1220 of the Appala- chian Environmental Laboratory, University of Maryland and Technical Report-4 of the Central Appalachian Raptor Ecology Program. Literature Cited Adamcik, R. S., A. W. Todd and L. B. Keith. 1979. Demographic and dietary responses of Red-tailed hawks during a snowshoe hare fluctuation. Can. Field Nat. 93:16-27. Bednarz, J. C. 1979. Productivity, nest sites and habitat of Red-shouldered and Red- tailed hawks in Iowa; status of habitat utilization and management of Red-shoul- dered hawks in Iowa. M.S. Thesis. Iowa State University. 85 pp. Bent, A. C. 1937. Life histories of North American birds of prey. Part I. U.S. Natl. Mus. Publ. No. 167. 409 pp. Bohm, R. T. 1978. A study of nesting Red-tailed hawks in central Minnesota. Loon 59:129-137. Burns, F, L. 1911. A monograph of the Broad-winged Hawk (Buteo platypterus). Wilson Bull. 23:139-320. Campbell, C. 1975. Ecology and reproduction of Red-shouldered hawks in the Waterloo region of southern Ontario. Raptor Res. 9:12-17. Craighead, J. J. and F. C. Craighead, Jr. 1956. Hawks, owls and wildlife. Stackpole Co., Harrisburg, Pennsylvania, and Wildlife Management Institute, Washington, D.C. 443 pp. Fitch, H. S., S. Freeman and D. Tillotson. 1946. Behavior and food habits of the Red- tailed hawk. Condor 48:205-237. Fitch, H. S., B. Glading and V. House. 1946. Observations on Cooper’s hawk nesting and predation. California Fish and Game 32:144-154. Gates, J. M. 1972. Red-tailed hawk populations and ecology in east central Wisconsin. Wilson Bull. 84:421-433. Hagar, D. 1957. Nesting populations of Red-tailed hawks and Horned owls in central New York state. Wilson Bull. 69: 263-271. Harris, W. 1971. Red-tailed hawk nesting success. Blue Jay 29:203. Hennessy, S. 1978. Ecological relationships of accipiters in northern Utah with special emphasis on the effect of human disturbance. M.S. Thesis. Utah State University. 66 pp. Henny, C, and H. Wight. 1972. Population ecology and environmental pollution: Red- tailed and Cooper’s hawks. In: Population Ecology of Migratory Birds: A Sym- posium. Patuxent Wildlife Research Center. U.S. Department of Interior. Wildlife Report 2:229-250. 24 RAPTOR RESEARCH Vol. 16, No. 1 Henny, C., F. Schmid, E. Martin and L. Hood. 1973. Territorial behavior pesticides and the population ecology of the Red-shouldered hawk in central Maryland. 1943-1971. Ecology 54:545-554. Howell, J., B. Smith, J. Holt and P. R. Osborne. 1978. Habitat structure and productivity in Red-tailed hawks. Bird Banding 49:162-171. Johnson, S. L. 1973. Post-fledging activity of the Red-tailed hawk. Raptor Res. 7:43-48. Ladino, A. 1980. Animal utilization of herbaceous and shrubby transmission line corri- dors and adjacent forest habitats. Unpublished M.S. Thesis, University of Mary- land, Appalachian Environmental Laboratory. Forstburg, Maryland. Luttich, S. N., L. B. Keith and J. D. Stephenson. 1971. Population dynamics of the Red- tailed hawk in Rochester, Alberta. Auk 88:75-87. Mader, W. 1978. A comparative nesting study of Red-tailed hawks and Harris hawks in southern Arizona. Auk 95:327-337. Mathiak, H. 1938. A key to hairs of the mammals of southern Michigan. J. Wildlife Mgt. 2:251-268. Matray, P. F. 1974. Broad-winged hawk nesting and ecology. Auk 91:307-324. Meng, H. 1965. Food habits of nesting Cooper’s hawks and Goshawks in New York and Pennsylvania. Wilson Bull. 71:169-174. Mosher, J. A. and P. F. Matray. 1974. Size dimorphism: a factor in energy savings for Broad-winged hawks. Auk 91:325-341. Orians, G. and F. Kuhlman. 1956. Red-tailed hawk and Horned owl populations in Wis- consin. Condor 58:371-385. Portnoy, J. W. and W. E. Dodge. 1979. Red-shouldered hawk nesting ecology and be- havior. Wilson Bull. 91:104-117. Reynolds, R. T. and H. M. Wight. 1978. Distribution, density and productivity of aecipi- ter hawks breeding in Oregon. Wilson Bull. 90:182-196. Roosa, D. M. 1964. Nesting of raptors in western Wright County. Iowa Bird Life 34:88-90. Rusch, D. and P. Doerr. 1972. Broad- winged hawk nesting and food habits. Auk 89:139-145. Seidensticker, J. C. and H. V. Reynolds. 1971. The nesting reproductive performance and chlorinated hydrocarbon residues in the Red-tailed hawk and Great Horned owl in south central Montana. Wilson Bull. 83:408-418. Smith, D. G. and J. R. Murphy. 1973. Breeding ecology of raptors in the eastern Great Basin in Utah. Brigham Young University. Biol. Sci. Bull. 18:1-76. Stewart, R. E. 1949. Ecology of a nesting Red-shouldered hawk population. Wilson Bull. 61:26-35. Titus, K. and J. A. Mosher. 1981. Nest site habitat selected by raptors in the central Ap- palachians. Auk 98:270-281. Wiley, J. 1975. The nesting and reproductive success of Red-tailed hawks and Red- shouldered hawks in Orange County, California. Condor 77:133-139. Williams, C. 1938. Aids to the identification of mole and shrew hairs with general com- ments on hair structure and hair determination. }. Wildlife Mgt. 2:239-249. UNUSUAL BEHAVIOUR OF THE SPOT-WINGED FALCONET ( SPIZIAPTERYX CIRCUMCINCTUS) by Roberto J. Straneck and Guillermo Vasina Museo Arg. de Ciencias Nat. Bernardino Rivadavia Av. Angel Gallardo 470 Buenos Aires 1405 Republica Argentina The following observations were made in Chulume, Rio Tercero, Province of Cordoba, Argentina (32°20’ S, 64°50’ W). The region is one of low hills, with native trees, dominated by Acacia caven, Celtis tala, Geoffroea decorticans, Lithraea molleoides. Average vegetation height is 4 m. The area is typical of half-open southern chaco forest. S piziapteryx circumcinctus is a little known species in a monotypic genus found in the chaco region of cen- tral-northern Argentina and extends slightly into the chaco of Paraguay (Olrog 1959). The first known nest and eggs were presumably found as recently as 1947. The falconets were using an old stick nest of an oven- bird (Furnariidae) (Dean 1971). Its relationship to other members of Falconidae is not clearly understood and while Brown and Amadon (1968) consider it to be related to the Pigmy Falcon ( Polihierax sp.) of Africa and south-western Asia, recent anatomical studies show that it is not related to Polihierax but rather the “aberrant Neotropical falcons,” especially the caracaras (Olson 1976) (See Figure 1). Figure 1.— Spot-winged Falconet in northern Argentina. Note this species’ similarity to the Pygmy Falcon, with regards to its posture, short wings and long tail. 25 Raptor Research 16(l):25-26 26 RAPTOR RESEARCH Vol. 16, No. 1 On 20 August 1980 we were recording Monk Parakeet ( Myiopsitta tnonachus ) calls in front of a solitary nest near a colony of about 20 nests located close to a more densely wooded area. We chose this nest in order to record single voices of M. monachus and then to evaluate their relationship with parakeet behaviour. At 18:10 hrs, while the sun was setting behind the hills, a pair of Spiziapteryx arrived and began making vocal displays which we recorded for half an hour using play-backs. The male came toward us, repeated its vocal display and flew toward the nesting colony of M. monachus. When we approached the colony, doing play-backs of his voice, he started emitting alarm calls. Despite the fact that it was getting dark, we could see him clearly emerging from a parakeet nest continuously emitting alarm calls. Simultaneously we could also hear the alarm calls of the parakeets. After perching for a few minutes about 10 m. from us the falconet flew towards another parakeet nest and entered it. To our great surprise, 4 parakeets left this nest, flew around it emitting alarm calls only to re-enter it a few minutes later. In the same nest were now the falconet and 4 parakeets together. We repeated the play-back of the falconet’s voice and the same procedure occurred again, namely, the male falconet left the nest, emitting a few high pitched alarm calls, perched only 6 m. from us, and then en- tered a third parakeet nest, out of which flew 6 parakeets, circled excitedly around the nest and entered it later with the falconet still inside. We did not use the play-back again and all birds remained where they were. It was obvious that the falco- net was to spend the night in a nest together with the 6 parakeets. It is worthwhile to note that due to the play-back work to which we submitted this individual we were able to make him leave and enter three differ- ent nests, all of them habitated by parakeets. This episode lasted about 45 min. We left the area at about 18:55. The female falconet was nowhere to be seen, and presumably left the area while we concentrated on our work with the male. We feel that this behavior of S. circumcinctus deserves more studies and detailed data, but we also believe that our observation of this particular individual should not be considered rare. On another occasion, while Straneck was recording voices of M. monachus in exactly the same place, he saw another falconet flying to- wards the colony. As long as the falconet was flying, the parakeets in the colony were excited, emitting alarm calls. However, as soon as the falconet perched on a tree in the middle of the colony, the parakeets quieted down and normal activity resumed. Only when he took wing, and showed the typical raptor silhouette did the colony become excited again. The behavior of this falconet around bulky stick nests with hole-type entrances is of particular interest in light of the fact that the African Pigmy Falcon ( P . semitorquatus ) nests and roosts in the nests of weaver finches (Ploceidae) (Maclean 1970). Weaver finch nests that are particularly used by the falcons are those of the Sociable Weaver ( Philetarius socius) and have the general configuration of a large Monk Parakeet colonial nest. While these two falcons may not be particularly related they may prove to have shown a similar evolu- tion of behavioral traits perhaps in response to the environment. For this work we used a Uher 4000 report IC recorder and Dan Gibson P 200 parabolic microphone with BASF DP 26 tapes. All recordings are in the possession of Straneck. Literature Cited Brown, L. & D. Amadon 1968. Eagles, Hawks and Falcons of the World. McGraw Hill, New York. Dean, A. 1971. Notes on Spiziapteryx circumcinctus. Ibis 113:101-102. Maclean, G. L. 1970. The Pygmy Falcon Polihierax semitorquatus. Keodoe 13:1-21. Olsen, S. L. 1976. The affinities of the falconid genus Spiziapteryx. Auk 93:633-636. Olrog Claes Chr. 1959. Las Aves Argentinas. Una guia de Campo Inst. M. Lillo. Tucuman, Argentina. A POSSIBLE HUNTING RELATIONSHIP BETWEEN TWO RAPTOR SPECIES by Steven S. Merchant Department of Wildlife Sciences Box 4901, New Mexico State University Las Cruces, New Mexico 88003 The high plains of eastern New Mexico provide a wintering area for numerous raptors, including the abun- dant Northern Harrier ( Circus cyaneus) and the less abundant but conspicuous Prairie Falcon ( Falco mexi- canus). While studying the Lesser Prairie Chicken ( Tympanuchus pallidicinctus ) in Roosevelt and Lea Coun- ties, New Mexico, a possible relationship between these 2 raptor species was noted. Raptor Research 16(l):26-27 Spring 1982 Merchant— Hunting Relationship 27 On 6 occasions throughout January and February 1980, I saw Prairie Falcons apparently hunting close to actively hunting Harriers. On these occasions, I saw a Harrier hunting over open grassland and cultivated grainfields in their typical low flying manner, while a Prairie Falcon flew approximately 30-50m above and 50- 100m behind. As the Harrier coursed across the fields, the accompanying falcon stooped on rising birds which were flushed by, the hawk. Although I saw neither species take prey, the association appeared deliber- ate. Bourne (1960) and Watson (1977:92) observed similar relationships between the Hen Harrier (C. c. cyaneus ) and Merlin (F. columbarius). These incidents may be an example of a behavioral symbiosis. Prairie Falcons often capture prey that flushes out in front of them (Enderson 1964). However, potential prey in good cover is often hesitant to flush due to the falcon’s flying ability. Conversely, the Harrier’s low flight pattern and long legs enable it to most effectively capture prey on, or very close to, the ground (Watson 1977:87). For avian prey, the apparent re- sponse to a Harrier overhead would thus be to flush ahead of the hawk. It is apparent then, that a Prairie Fal- con could facilitate its own hunting by utilizing a hunting Harrier as a flusher. By hunting in association with a Harrier, a Prairie Falcon may actually increase its encounter rate with prey items. The benefit which the Harrier receives from this relationship is less apparent. Perhaps the hawk benefits by taking birds which are hesitant to flush in the presence of the falcon. Literature Cited Bourne, W. R. P. 1960. A hunting partnership between two birds of prey. Ibis: 102:136. Enderson, J. H. 1964. A study of the prairie falcon in the central Rocky Mountain region. Auk 81:332-352. Watson, D. 1977. The Hen Harrier. T. and A. D. Poyser, Berkhamsted. 307 pp. FOOD OF THE SPOTTED OWL IN UTAH by Phillip W. Wagner Utah Division of Wildlife Resources Salt Lake City, Utah 84116 Carl D. Marti Department of Zoology Weber State College Ogden, Utah 84408 and Thomas C. Boner Utah Division of Wildlife Resources Salt Lake City, Utah 84116* In this paper we report a sample of prey of the Mexican Spotted Owl (S trix occidentalis lucida) from south- ern Utah. Food habits of this species are poorly known compared to many other North American owls (Ear- hart and Johnson 1970). Diet of the Mexican race is least well known. A few casual records are available from Arizona and New Mexico (Huey 1932, Ligon 1926) but only seven prey individuals were previously reported for Utah (Kertell 1977). Forsman (1976) and Barrows (1980) have reported the only comprehensive analysis of Spotted Owl foods from Oregon (S. o. occidentalis ) and California (S. o. caurina), respectively. Reports of other, mostly very small collections of prey, were reviewed by Barrows (1980) and Zarn (1974). The Spotted Owl is listed as a rare permanent resident in Utah (Behle and Perry 1975) and is found in habi- tats very different than the dense, old growth forests occupied by other races. Kertell (1977) felt that cool re- treats were necessary for roosting and nesting in the hot summers of southern Utah; these are found in nar- row, steep-walled canyons. "Present address; 2215 S. Latah, Boise, Idaho. Raptor Research 16(l):27-28 26 RAPTOR RESEARCH Vol. 16, No. 1 On 20 August 1980 we were recording Monk Parakeet ( Myiopsitta tnonachus ) calls in front of a solitary nest near a colony of about 20 nests located close to a more densely wooded area. We chose this nest in order to record single voices of M. monachus and then to evaluate their relationship with parakeet behaviour. At 18:10 hrs, while the sun was setting behind the hills, a pair of Spiziapteryx arrived and began making vocal displays which we recorded for half an hour using play-backs. The male came toward us, repeated its vocal display and flew toward the nesting colony of M. monachus. When we approached the colony, doing play-backs of his voice, he started emitting alarm calls. Despite the fact that it was getting dark, we could see him clearly emerging from a parakeet nest continuously emitting alarm calls. Simultaneously we could also hear the alarm calls of the parakeets. After perching for a few minutes about 10 m. from us the falconet flew towards another parakeet nest and entered it. To our great surprise, 4 parakeets left this nest, flew around it emitting alarm calls only to re-enter it a few minutes later. In the same nest were now the falconet and 4 parakeets together. We repeated the play-back of the falconet’s voice and the same procedure occurred again, namely, the male falconet left the nest, emitting a few high pitched alarm calls, perched only 6 m. from us, and then en- tered a third parakeet nest, out of which flew 6 parakeets, circled excitedly around the nest and entered it later with the falconet still inside. We did not use the play-back again and all birds remained where they were. It was obvious that the falco- net was to spend the night in a nest together with the 6 parakeets. It is worthwhile to note that due to the play-back work to which we submitted this individual we were able to make him leave and enter three differ- ent nests, all of them habitated by parakeets. This episode lasted about 45 min. We left the area at about 18:55. The female falconet was nowhere to be seen, and presumably left the area while we concentrated on our work with the male. We feel that this behavior of S. circumcinctus deserves more studies and detailed data, but we also believe that our observation of this particular individual should not be considered rare. On another occasion, while Straneck was recording voices of M. monachus in exactly the same place, he saw another falconet flying to- wards the colony. As long as the falconet was flying, the parakeets in the colony were excited, emitting alarm calls. However, as soon as the falconet perched on a tree in the middle of the colony, the parakeets quieted down and normal activity resumed. Only when he took wing, and showed the typical raptor silhouette did the colony become excited again. The behavior of this falconet around bulky stick nests with hole-type entrances is of particular interest in light of the fact that the African Pigmy Falcon ( P . semitorquatus ) nests and roosts in the nests of weaver finches (Ploceidae) (Maclean 1970). Weaver finch nests that are particularly used by the falcons are those of the Sociable Weaver ( Philetarius socius) and have the general configuration of a large Monk Parakeet colonial nest. While these two falcons may not be particularly related they may prove to have shown a similar evolu- tion of behavioral traits perhaps in response to the environment. For this work we used a Uher 4000 report IC recorder and Dan Gibson P 200 parabolic microphone with BASF DP 26 tapes. All recordings are in the possession of Straneck. Literature Cited Brown, L. & D. Amadon 1968. Eagles, Hawks and Falcons of the World. McGraw Hill, New York. Dean, A. 1971. Notes on Spiziapteryx circumcinctus. Ibis 113:101-102. Maclean, G. L. 1970. The Pygmy Falcon Polihierax semitorquatus. Keodoe 13:1-21. Olsen, S. L. 1976. The affinities of the falconid genus Spiziapteryx. Auk 93:633-636. Olrog Claes Chr. 1959. Las Aves Argentinas. Una guia de Campo Inst. M. Lillo. Tucuman, Argentina. A POSSIBLE HUNTING RELATIONSHIP BETWEEN TWO RAPTOR SPECIES by Steven S. Merchant Department of Wildlife Sciences Box 4901, New Mexico State University Las Cruces, New Mexico 88003 The high plains of eastern New Mexico provide a wintering area for numerous raptors, including the abun- dant Northern Harrier ( Circus cyaneus) and the less abundant but conspicuous Prairie Falcon ( Falco mexi- canus). While studying the Lesser Prairie Chicken ( Tympanuchus pallidicinctus ) in Roosevelt and Lea Coun- ties, New Mexico, a possible relationship between these 2 raptor species was noted. Raptor Research 16(l):26-27 28 RAPTOR RESEARCH Vol. 16, No. 1 In view of the difference in habitat, comparative studies of the 3 races of Spotted Owl could prove valuable in terms of trophic divergence. Accordingly, we present here additional food data for the Mexican race. Even though this sample is limited in size and locality, some interesting comparisons are possible with diets of Spotted Owls from other areas. Spotted Owl pellets were collected in 1977 from below roosts in Capitol Reef National Park, Utah, where Spotted Owls were observed. The collection site was a deep, narrow sandstone canyon. Water in this, and the main canyon it adjoins, was ephemeral. Vegetation in the canyon bottom was a mixture of grasses, forbs, cacti and sparsely scattered boxelder ( Acer negunda), cottonwood ( Populus spp.) and bigtooth maple (A. grandi- dentatum ) trees. Vegetation on the plateau above the canyon was dominated by Utah juniper (. Juniperus os- teosperma), Colorado pinyon ( Pinus edulis) and mixture of shrubs (S hepherdia, Cercocarpm and Ephedra spp.). Prey identified are presented in Table 1. Table 1. Prey of the Spotted Owl from southern Utah. Prey species Number Percent frequency Antrozous pallidus 1 0.9 Peromyscus spp. 16 15.2 Neotoma cinerea 14 13.3 Neotoma lepida 53 50.5 Neotoma spp. 9 8.6 Orthoptera 1 0.9 Arachnida (scorpion) 1 0.9 unidentified invertebrates 10 9.5 Total 105 100.0 In California (Barrows 1980) and Oregon (Forsman 1976), nearly all prey was characteristic of forest habi- tats. Interestingly, even though the habitat in southern Utah is very different, consisting of desert canyons and plateaus, the major prey was woodrats ( Neotoma spp.) as it was in California. Woodrats ranked second overall in diet biomass of Oregon Spotted Owls and were the most important prey in drier habitats there. Fewer mammalian species occurred in the Utah diet and no birds were found. These differences could be attribu- table to the smaller sample size from Utah. Obviously, much more study is needed to elucidate the feeding ecology of this species in the distinctly different areas of its distribution. We thank Jerry Hoddenback for collecting some of the pellets. LITERATURE CITED Barrows, C. 1980. Feeding ecology of the Spotted owl in California. Raptor Res. 14:73-78. Behle, W. H. and M. L. Perry. 1975. Utah birds. Utah Mus. Nat. Hist. Salt Lake City. Earhart, C. M. and N. K. Johnson. 1970. Size dimorphism and food habits of North American owls. Condor 72:251-264. Forsman, E. 1976. A preliminary investigation of the Spotted owl in Oregon. M.S. Thesis, Oregon State Univ,, Corvallis, Huey, L. M. 1932. Note on the food of an Arizona Spotted owl. Condor 34:100-101. Kertell, K. 1977. The Spotted owl at Zion National Park, Utah. Western Birds 8:147-150. Ligon, J. S. 1926. Habits of the Spotted owl. Auk 43:421-429. Zarn, M. 1974. Spotted Owl. Habitat Manage. Series Unique Endangered Species No. 10, Bur. Land Manage., Denver. Spring 1982 Abstracts 29 ABSTRACTS OF THESES AND DISSERTATIONS PREY SIZE SELECTION BY WILD AMERICAN KESTRELS ( FALCO SPARVERIUS) WINTERING IN SOUTHCENTRAL FLORIDA In order to test prey size preferences, free ranging American Kestrels ( Falco spar- verius ) hunting from roadside perches were each offered a pair of white laboratory mice ( Mus musculus ), representing two of four size categories (7-14 g, 15-22 g, 23-30 g, 31-38 g). Female kestrels were observed significantly more often than males in the study area. The larger mouse of a pair was selected significantly more often than the smaller mouse. Electivity indices showed that mice of the smallest size category were selected below their availability and that the greatest proportional number of attacks was directed towards mice of the largest size category. Mouse activity, determined by the number of 10 cm grid crossings, was directly proportional to mouse size. Thus either differential size or activity may have functioned as a stimulus for prey size selection. These results support an energy maximizing model of predator choice and are in direct opposition to results obtained from laboratory studies of owl and shrike prey size selec- tion. A new technique for testing preferences of roadside hunting raptors for variable prey characteristics is described. Smallwood, John A. 1981. Prey size selection by wild American Kestrels ( Falco spar- verius) wintering in southcentral Florida. M.S. Thesis, Miami University, Oxford, Ohio. BOOK REVIEWS The Birds of Prey of Southern Africa. C. G. Finch-Davies and A. C. Kemp. 1980. Win- chester Press, Ltd., Johannesburg, South Africa. 339 pp. This is an exceptional book that unfortunately is limited to 1726 volumes. Therefore, if you don’t have a copy by now you may not get one. The book certainly merits a re- view because of the significant contribution to the history of ornithological art and biol- ogy of African raptors it presents. Basically the book contains the art work of the late Lt. C. G. Finch-Davies (1875-1920) with commentary on each species by Alan Kemp, Curator of birds at the Transvaal Museum. Finch-Davies grew up in British colonialist tradition and like so many 19th century British ornithologists lived in both India and Af- rica. He had a varied and controversial career and if he takes a place in history it will be because of his art work and not his career and achievements as a military man. While the late and legendary Leslie Brown has often been said to be the authority on African raptors his only edge on Alan Kemp has been his age. Alan’s intimate knowledge of rap- tors, his keen ability as an observer and his intuitive common sense about raptors biolo- gy have been manifest throughout his narrative species accounts. The book contains 141 color plates, including the frontispiece; 124 plates of diurnal raptors and 17 of owls. Of the 59 species of diurnal raptors shown all but 15 depict adult and juvenile plumage and in all but a handful of cases there are more than one plate per species. The 12 species of owls shown are all adult but one. While most of the art work 30 RAPTOR RESEARCH Vol. 16, No. 1 is of a similar quality it spans a 10 year period from 1910 to 1919. Some plates show ex- cellent fidelity, eg. the cream-backed form of the Bateleur ( Terathopius ecaudatus ) while others have some minor problems with body proportions such as the juvenile Black Sparrowhawk {Accipiter melanoleucus). Plates that I particularly like are the male Jackal Buzzard ( Buteo rufofuscus ), immature Tawny Eagle (Aquila rapax) and the adult female White-faced Owl ( Otus leucotis ). Several species, eg. Smaller Banded Snake- eagle ( Circaetus cinerascens ), and Long-legged Buzzard ( Buteo rufinus ) have occurred in southern Africa since Finch-Davies’ time and although not illustrated they are nonethe- less mentioned by Kemp. While not a trained ornithologist Finch-Davies became an excellent observer and clarified the fact that the immature of the Red-headed Falcon (now named Falco chi- quera ) was just that and not a different species that had been named ( Falco horsbrughi). He also clarified a similar adult-immature confusion with a hawk-eagle (Hieraaetus). Dr. Kemp’s background is thoroughly zoological and African; born in Zimbabwa of British ancestry. While he has a keen interest in raptors, his Ph.D. work was on hornbills (Tocus sp). Much of the earlier nomenclature of raptors is preserved by Kemp and differs from that preferred in the most recent Peters Check-list of Birds of the World. Many of the forms Kemp calls full species are referred to as “megasubspecies” in Peters; forms approaching full species status. For example, Kemp places the Tawny Eagle (. Aquila rapax) as a species apart from the Steppe Eagle {Aquila nipalensis ) and two dis- tinctive African buteos {Buteo rufofuscus and B. augur) are treated as different species rather than both subspecies of the former as preferred in Peters. I do not know what bird is called the Mountain Buzzard {Buteo tachardus ) by Kemp but I presume it to be the African Mountain Buzzard {B. oreophilus) of other check-lists. Dr. Kemp’s intuitive knowledge of raptors is superb. He has included new data in the book from his own ob- servations, for example, data on the Dickinson’s Kestrel {Falco dickinsoni) behavior. When my family and I visited the Kemps in Pretoria in 1981, I watched the Dickinson’s Kestrels in a large cage in his backyard and one need only watch them and their fast parrot-like movements for a short period to realize how different they are from other “kestrels”. Through studies like Dr. Kemp is doing he should help clarify the more accu- rate affinities and relationships of many of the aberrant African raptors such as this kestrel. I heartily recommend that one familiarize himself with this book and glean the new knowledge of the remarkable diverse and abundant African raptor fauna that is scat- tered throughout the text. This book will stand for some time to come as the most com- plete of its kind on birds of prey of Southern, if not all, Africa. C. M. White ANNOUNCEMENTS THE WILLIAM C. ANDERSEN MEMORIAL AWARD 1. THE AWARD An award for the best paper presented by a student at each Raptor Research Founda- tion Annual Meeting. 2. THE MAN Although his profession was chemistry professor at Otero Junior College, La Junta, Colorado, Bill Andersen’s first love was raptors. He established the Ornithology Re- Spring 1982 Announcements 31 search Center at Otero Jr. College as a medium for fund-gathering for the raptor field investigations he and his students conducted. His interest in the raptors utilizing the grasslands of southeastern Colorado naturally evolved into developing a solution to the almost universal problem of public misunderstanding and persecution of birds of prey. Bill established a rehabilitation facility to treat injured raptors which were brought to him by the public and he tirelessly lectured to service clubs and school groups about the benefits of raptors. Success of his efforts was apparent from the re- duction in shot raptors encountered there in the wild. He was a strong supporter of the Foundation, and a number of his students accompanied him to the Foundation’s Annual Meetings. Bill’s enthusiasm, sincerity, and humor sparked an interest in rap- tors among many of his students and associates. While participating in the 1980 North American Peregrine Falcon Survey Bill and a partner were canoeing on the hazardous Churchill River in northern Manitoba. Owing to a severe drawdown in the water level, they unexpectedly encountered ex- tremely turbulent water and capsized. Bill disappeared, and presumably drowned, while engaged in two of the activities he most enjoyed. Raptors and raptorophiles have lost a strong ally. 3. PROCEDURES a. When submitting an abstract of a paper and applying for a place in the paper ses- sions of a RRF Annual Meeting, a student wishing to be considered for this award must include the following note on the abstract: “to be considered for the Ander- sen Student Award.” b. Eligibility: (i) the student must be a registered full time or part time student at a recog- nized educational institution. (ii) the information contained in the paper must have been collect- ed/synthesized primarily by the student. (iii) the paper must have been organized and written by the student with (at most) only relatively minor editorial assistance from faculty and colleagues. (iv) if necessary the paper may carry the names of supervisor(s) and col- league^) as joint authors. c. A committee of three RRF officers and/or directors (or their appointees) will in- dependently evaluate all eligible papers as presented, and will meet to determine the award winner. d. The award will be presented before the close of each RRF Annual Meeting and will be announced in Raptor Research and other journals and ornithological newsletters. e. The award will consist of an inscribed plaque. Criteria for evaluation should include, where applicable, these categories: —the presentation 30 —ease of delivery —quality of AV aids —adherence to time limit —the organization of topics within the paper 20 —ease of following the logic and steps involved 32 RAPTOR RESEARCH Vol. 16, No. 1 —the information presented —thoroughness of background explanations —quality of the investigation —quality of interpretation of findings 50 100 STUDENT INTERNSHIPS IN RAPTOR RESEARCH AT McGILL UNIVERSITY , MONTREAL For the summer of 1982, the Macdonald Raptor Research Centre of McGill Univer- sity is offering four student internships to university students interested in raptor re- search, rehabilitation and public awareness. The Centre maintains a colony of 400 cap- tive hawks, falcons and eagles and also conducts field studies in the surrounding area. Each student will gain experience in raptor care and management, public tours of the Centre, rehabilitation of sick and injured raptors, and each will be assigned to a specific research project. Free university residence is available within walking distance of the Centre. Please submit a resume of previous experience with a letter of recommendation to: Dr. David M. Bird Raptor Research Centre Mcdonald Campus of McGill University 21,111 Lakeshore Road Ste. Anne de Bellevue, Quebec H9C ICO 1-514-457-2000, ext. 345 MRRC RAPTOR RESEARCH AVAILABLE A compendium of all research projects either completed or in progress during the years 1974 to 1981 at McGill University’s Raptor Research Centre has been published. Abstracts of 27 projects dealing with birds of prey are included. For a copy of the re- port, please send $2.00 for handling charges to Dr. David Bird at the above address. ABSTRACTS OF 1981 RRF CONFERENCE AVAILABLE The 1981 Raptor Research Foundation conference in Montreal was a resounding suc- cess in spite of a modest turnout (300 participants) compared to previous years. Federal restrictions on travel prevented many U.S. federal officials from attending. Abstracts of approximately 50 papers presented at the RRF meeting are presently available. If you wish copies, please send your request along with $2.00 per copy to: Ms. Toni Bird Raptor Research Centre Macdonald Campus of McGill University 21,111 Lakeshore Road Ste. Anne de Bellevue, Quebec H9X ICO THE RAPTOR RESEARCH FOUNDATION, INC. OFFICERS President Dr. Jeffrey L. Lincer, Office of Environmental Management, P.O. Box 8, Sarasota, Florida 33578 Vice-President Dr. Joseph R. Murphy, Department of Zoology, 167 WIDB, Brigham Young University, Provo, Utah 84602 Secretary Ed Henckel, RD 1 Box 21, Rose Hill Farm, Phillipsburg, New Jersey 08865 Treasurer Dr. Gary E. Duke, Department of Veterinary Biology, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota 55108 Address all matters dealing with membership status, dues, publication sales, or other financial transactions to the Treasurer. See inside front cover. Send changes of address to the Treasurer. Address all general inquiries to the Secretary. See inside front cover for suggestions to contributors of manuscripts for Raptor Research , Raptor Research Reports , and special Raptor Research Foundation publications. BOARD OF DIRECTORS Eastern Dr. Mark R. Fuller, Migratory Bird Lab., U.S.F.W.S., Patuxent Re- search Center, Laurel, Maryland 20811 Central Dr. Patrick Redig, Department of Veterinary Biology, College of Vet- erinary Medicine, University of Minnesota, St. Paul, MN 55101 Pacific and Mountain Dr. Joseph R. Murphy, Department of Zoology, 167 WIDB, Brigham Young University, Provo, Utah 84602 Canadian Eastern Dr. David Bird, Macdonald Raptor Research Center, Mac- donald College, Quebec, H9X ICO, Canada Western Dr. R. Wayne Nelson, 6307-41 Ave., Camrose, Alberta T4V 2W6, Canada At Large Dr. Richard R. Olendorff, Division of Resources (C-932), B.L.M., 2800 Cottage Way, Sacramento, California 95825 At Large Dr. Stanley Temple, Department of Wildlife Ecology, Russell Labo- ratory, University of Wisconsin, Madison, Wisconsin 53706 At Large Dr. Thomas Dunstan, Biology Dept., Western Illinois University, Macomb, Illinois 61455