RAPTOR RESEARCH NEWS Volume 5 Number 4 July- August 1971 Editors: Byron E. Harrell Donald V Hunter, Jr. Raptor Research Foundation, Inc. c/o Department of Biology University of South Dakota Vermillion, South Dakota 57069 U.S.A. NOTES, NEWS, AND QUERIES Publication Plans for 1972 90 New Editor of Raptor Research 106 Special Conference on Captivity Breeding of Birds of Prey 106 Raptor Research Abstracts 107 Notice of Conference on Raptor Conservation Techniques 107 Marked Ospreys 107 PAPERS AND REPORTS Estimations Relative to Birds of Prey in Captivity in the United States of America (Roger Thacker) 108 Research Planning Conference on Peregrines and Other Birds of Prey, Part 2 (Keith Hodson) 123 Sex Determination in Birds of Prey by Laparotomy (Phillip T. Lawson and Earl L. Kittle) 132 NOTES, NEWS, AND QUERIES Publication Plans for 1972. Raptor Research News will undergo further evolution. The changes are designed to make it a more acceptable journal for the publication of high qual- ity research papers while retaining features of informality in information exchange. The following changes are being insti- tuted: 1. Change in title to Raptor Research ', the volume numbers will be consecutive with those of its predecessor. 2. Changes in format: increased page size, more generous margins, trimmed edges, cover, mailing in an envelope, avail- ability of reprint orders. 3. Change to quarterly: the amount of material will be greater but the reduced frequency will increase the probabil- ity of regular undelayed appearance. Publication dates will be the last days of February, May, August, and November. Pap- ers should be in the hands of one of the editors about two months before publication. 4. Articles of opinion or ideas and reports of various sorts will be separated from research papers. New Editor of Raptor Research. We are happy to announce the appointment of the new Editor, Dr. Richard R. Olendorff, 3317 Olympus Dr., Bremerton, Washington 98310. Dr. Olen- dorff, who is currently on a post-doctoral fellowship with the American Museum of Natural History, completed his Ph.D. at Colorado State University. He has done considerable work on raptors and is the author of our Report No. 1 and compiler of an important bibliography. Byron E. Harrell and Donald V. Hunter, Jr. will continue as Associate Editors. Material for Raptor Research may be sent to any of the Editors. Special Conference on Captivity Breeding of Birds of Prey. On November 22 and 23, 1971 Raptor Research Foundation sponsored this conference which was held at Sioux Falls, South Dakota. Over 80 persons attended, coming from many 106 107 states and provinces. It was enormously stimulating and from all reports was considered highly successful. Because of the great interest an extended report is planned. A transcript is well along in preparation and edited sections of the ten panels will be issued as they are completed as a supplement to Raptor Research. Raptor Research Abstracts. The Abstracts will be initiated quarterly beginning in March. More details will appear in the double issue of the News now in press. NOTICE. Conference on Raptor Conservation Techniques. The Raptor Research Foundation in cooperation with the De- partment of Fishery and Wildlife Biology, Colorado State University, is sponsoring a symposium on the status of wild populations and on captivity breeding of birds of prey, to be held at Fort Collins, Colorado, 17-20 November 1972. Papers on the following topics are invited: Population inventories. Productivity studies. Investigations of the effects of biocides and industrial wastes (PCB’s) on raptor populations. Popula- tion management and conservation, and Captivity breeding of raptors by individuals, academic institutions and zoological gardens. The scope of the conference is worldwide and contri- butions from abroad are expected. Anyone wishing to present a paper or to attend should contact Dr. Richard R. Olendorff, 3317 Olympus Drive, Bremerton, Washington 98310U.S.A., or Dr. Byron E. Harrell, Raptor Research Foundation, Inc., c/o Biology Department, University of South Dakota, Vermil- lion, South Dakota 57069 U.S.A. The deadline for submit- ting abstracts is October 15, 1972. Marked Ospreys. Persons sighting Ospreys with a yellow plastic jess attached to the left leg should notify Donald R. Johnson, Department of Biology, University of Idaho, Mos- cow, Idaho 83843, specifying date and location of sightings. Fifteen nestling Ospreys were so marked during the past nest- ing season on Lakes Coeur d’Alene and Pend Oreille in nor- thern Idaho in an effort to determine the time and route of migration in these populations. ESTIMATIONS RELATIVE TO BIRDS OF PREY IN CAPTIVITY IN THE UNITED STATES OF AMERICA by Roger Thacker Department of Animal Laboratories The Ohio State University Columbus, Ohio 43210 Introduction. Counts relating to birds of prey in captivity have been accomplished in some European countries; how- ever, to the knowledge of this author no such information is available in the United States of America. The following paper consists of data related to this subject collected during 1969-1970 from surveys carried out in many different direc- tions within this country. Methods. In an attempt to obtain as clear a picture as pos- sible, counts were divided into specific areas: Research, Zoo- logical, Falconry, and Pet Holders. It became obvious as the project advanced that in some cases there was overlap from one area to another; an example of this being a falconer working with a bird both for falconry and research purposes. In some instances such as this, the author has used his own judgment in placing birds in specific categories; in other in- stances received information has been used for this purpose. It has also become clear during this project that a count of “pets” is very difficult to obtain. Lack of interest, non-coop- eration, or no available information from animal sales firms makes the task very difficult, as unfortunately, to obtain a clear dispersal picture it is from such sources that informa- tion must be gleaned. However, data related to the importa- tion of birds of prey as recorded by the Bureau of Sport Fisheries and Wildlife is included, and it is felt some observa- tions can be made from these figures. Within the specific areas used for count purposes, the fol- lowing methods were utilized: Research — were sent to a total of one hundred and five universities, government agencies, and private organiza- tions. Of this total, seventy-one replies were received. Thirty- 108 109 seven were in the affirmative, but the number of persons holding raptors exceeds this number, it representing mainly agencies and organizations in which individuals are either employed or are members. Zoological Societies— were sent to one hundred and sixty-two public and private zoological societies. One hun- dred and fifteen replies were received of which ninety-one were in the affirmative. Falconry— held for falconry purposes are quite difficult to gauge. Figures used in this count were obtained from state agencies and private organizations expressing interest in birds of prey. The difficulty of a count lies not so much in total numbers as species held. Therefore, over-all numbers will be considered in opposition to individual species. In other re- turns specific numbers were not given, but answers were phrased, “small, medium, or large.” Interpretation of such answers rests entirely with the author. Counts— Birds of Prey in Captivity-Research and Zoolog- ical. The following section tabulates results of counts from surveys. Names for the Order Falconiformes are taken from Eagles, Hawks and Falcons of the World by Leslie Brown and Dean Amadon, and those for the Order Strigiformes from Birds of Prey of the World by Mary Louise Grossman and John Hamlet. ORDER FALCONIFORMES Research Zoos Family Cathartidae Cathartes aura Cathartes burrovianus Coragyps atratus Sarcorhamphus papa Gymnogyps Turkey Vulture Yellow-headed Vulture Black Vulture King Vulture California Condor 7 43 5 3 35 53 California nils Vultur gryphus Andean Condor 9 41 Family Pandionidae Pandion haliaetus Osprey 3 110 Family Accipitridae Elanus leucurus Elanus caeruleus Rostrhamus sociabilis Ictinia mississippiensis Milvus migrans Milvus milvus Haliastur sphenurus Haliastur indus Haleaeetus leucogaster Haliaeetus vocifer Haliaeetus leucoryphus Haliaeetus leucocephalus Haliaeetus albicilla Haliaeetus pelagicus Ichthyophaga ichthyaetus Gypohierax angolensis Neophron percnopterus Gypaetus barbatus Necrosyrtes monachus Gyps bengalensis Gyps africanus Gyps himalayensis Gyps fulvus Sarcogyps calvus Aegypius monachus Trigonoceps occipitalis Terathopius ecaudatus Spilornis cheela Geranospiza caerulescens Circus cyaneus Melierax canorus Accipiter gentilis Accipiter striatus Accipiter fasciatus Accipiter badius Accipiter cooperii White-tailed Kite Black-shouldered Kite Snail/Everglade Kite Mississippi Kite Black/Pariah Kite Red Kite Whistling Eagle White-headed Sea Eagle White-bellied Sea Eagle African Fish Eagle Pallas’ Sea Eagle Bald Eagle White-tailed Sea Eagle Steller’s Sea Eagle Grey-headed Fishing Eagle Vulturine Fish Eagle Egyptian Vulture Lammergeier Hooded Vulture Indian White-backed Vulture African White-backed Vulture Himalayan Griffon Griffon Vulture Indian Black Vulture Cinereous Vulture White-headed Vulture Bateleur Crested Serpent Eagle Crane Hawk Marsh Hawk Pale Chanting Goshawk Northern Goshawk Sharp-shinned Hawk Australian Goshawk Shikra Cooper’s Hawk 11 30 4 4 12 1 1 2 3 5 1 3 17 8 9 5 102 3 4 3 6 32 2 2 2 2 1 14 8 13 2 3 12 6 7 2 3 2 2 2 7 Ill Leucopternis Semiplumbeous Hawk 2 semiplumbea Leucopternis albicollis White Hawk 3 Buteogallus anthracinus Common Black Hawk 1 Buteogallus urubitinga Great Black Hawk 5 Harpyhaliaetus solitarius Black Solitary Eagle 1 Heterospizias Savannah Hawk 19 meridionalis Geranoaetus Grey Eagle-buzzard 4 melanoleucus Parabuteo unicinctus Harris’s Hawk 7 21 Buteo nitidus Grey Hawk 4 Buteo magnirostris Roadside Hawk 3 Buteo lineatus Red-shouldered Hawk 11 9 Buteo platypterus Broad-winged Hawk 6 7 Buteo brachyurus Short-tailed Hawk 3 Buteo swainsonii Swainson’s Hawk 9 19 Buteo solitarius Hawaiian Hawk 4 Buteo ventralis Red-tailed Buzzard 11 Buteo jamaicensis Red-tailed Hawk 41 155 Buteo lagopus Rough-legged Buzzard 9 Buteo rufinus Long-legged Buzzard 1 Buteo regalis Ferruginous Hawk 2 24 Buteo auguralis African Red-tailed 3 Morphnus guianensis Buzzard Guiana Crested Eagle 7 Harpia harpyja Harpy Eagle 17 Harpyopsis novaeguineae New Guinea Harpy Eagle 1 Pithecophaga jefferyi Philippine Monkey- 8 Aquila rapax eating Eagle Tawny/Steppe Eagle 1 5 Aquila heliaca Imperial Ea^e 2 5 Aquila wahlbergi Wahlberg’s Eagle 2 Aquila chrysaetos Golden Eagle 24 173 Aquila audax Wedge-tailed Eagle 14 Aquila verreauxi Verreaux’s Eagle 1 Hieraaetus fasciatus African Hawk-eagle 5 2 Hieraaetus pennatus Booted Eagle 2 Hieraaetus morphnoides Little Eagle 1 Spizastur melanoleucus Black and White 1 Lophoaetus occipitalis Hawk-eagle Long-crested Eagle 1 112 Spizaetus cirrhatus Changeable Hawk-eagle Spizaetus tyrannus Black Hawk-eagle Spizaetus ornatus Ornate Hawk-eagle Stephanoaetus coronatus Crowned Eagle Polemaetus bellicosus Martial Eagle 4 2 5 3 4 Family Sagittariidae Sagittarius serpentarius Secretary Bird 32 Family Falconidae Daptrius ater Yellow-throated 4 Phalcoboenus Caracara Mountain Caracara 3 megalopterus Polyborus plancus Common Caracara 55 Milvago chimachima Yellow-headed 3 Micrastur semitorquatus Caracara Collared Forest Falcon 2 3 Microhierax caerulescens Red-legged Falconet 9 14 Falco sparverius American Kestrel 127 59 Falco chicquera Red-headed Falcon 2 5 Falco columbarius Merlin 22 2 Falco berigora Brown Hawk 1 Falco rufigularis Bat Falcon 2 Falco biarmicus Lanner Falcon 6 Falco mexicanus Prairie Falcon 18 4 Falco cherrug Saker Falcon 4 Falco rusticolus Gyrfalcon 16 Falco deiroleucus Orange-breasted 2 Falco peregrinus Falcon Peregrine Falcon 114 2 TOTALS 510 1,234 Falconry, As was stated in the introduction, state agencies have been the source of much information pertaining to fal- conry. A figure of raptors in possession for falconry purposes is difficult to arrive at; however on information supplied, it is estimated that it is approximately 1200-1300 broken down as follows: 113 State Returns of Raptors Held for Falconry 1969/70 Alabama 1 Alaska 8 Arizona 23 California 450 Colorado 70 Florida 25 Georgia 2 Idaho 18 Illinois 50 Indiana 35 Iowa 11 Kansas 20 Kentucky 20 Louisiana 4 Maryland 40 Michigan 25 Minnesota 35 Mississippi 2 Missouri 25 Montana 5 Nebraska 2 New Mexico 4 Nevada 10 North Dakota 5 Oklahoma 6 Oregon 14 Pennsylvania 59 Rhode Island 1 South Dakota 10 South Carolina 8 Texas 15 Utah 12 Virginia 30 Washington 90 Wisconsin 40 Wyoming 50 TOTAL 1,225 Percentage of Species Held in Relation to Total Numbers 1969/70. These are based on over-all average of states provid- ing actual species counts. Genus Buteo/ Parabuteo Red-tailed Hawk, Ferruginous Hawk, Swainson’s Hawk, Harris’s Hawk, Rough-legged Hawk Genus Accipiter Goshawk, Cooper’s Hawk, Sharp-shinned Hawk, etc. Genus Falco Kestrels, Merlins, Prairie Falcon, Peregrine Falcon, Gyrfalcon, Saker Falcon, Lanner Falcon, Lugger Falcon Others 58% 13 % 28% TOTAL 100% 114 Order STRIGIFORMES Research Zoos Family Tytonidae Tyto alba Barn Owl 14 72 Phodilus badius Bay Owl 4 Family Strigidae Otus asio Common Screech Owl 26 77 Otus choliba Tropical Screech Owl 2 Otus watsonii Tawny-bellied Screech Owl 2 Lophostrix cristata Crested Owl 2 Bubo virginianus Great Horned Owl 14 180 Bubo bubo Eagle-owl 12 Bubo nipalensis Forest Eagle-owl 2 Ketupa ketupa Malay Fish Owl 8 Ketupa zeylonensis Brown Fish Owl 3 Pulsatrix perspicillata Spectacled Owl 7 Pulsatrix koeniswaldiana White-chinned Owl 3 Nyctea scandiaca Snowy Owl 6 45 Glaucidium brasilianum Ferruginous Pigmy Owl 3 Glaucidium gnoma Northern Pigmy Owl 6 Glaucidium cuculoides Cuckoo Owlet 2 Micrathene whitneyi Elf Owl 14 Ninox novaeseelandiae Spotted Hawk Owl 2 Athene noctua Little Owl 5 Speotyto cunnicularia Burrowing Owl 30 47 Ciccaba virgata Mottled Owl 3 Ciccaba huhula Black-banded Owl 2 Strix varia Barred Owl 4 39 Strix nebulosa Great Grey Owl 4 Strix aluco Tawny Owl 6 Strix leptogrammica Brown Wood Owl 3 Rhinoptynx clamator Striped Owl 5 Asio otus Long-eared Owl 4 Asio flammeus Short-eared Owl 14 Aegolius acadicus Saw-whet Owl 16 TOTALS 94 594 Falconry. Bubo virginianus Great Horned Owl 7 Birds of Prey Held for Research, Zoological and Falconry Purposes 115 Falconiformes Research Zoological Falconry Strigiformes Research Zoological Falconry 510 17.17% 1,234 41.56% 1,225 41.25% 94 13.52% 594 85.47% 7 1.00% Final Total 2,969 695 3,664 Birds of Prey Imported into the United States 1968/69 Order FALCONIFORMES Family Cathartidae 1968 1969 Sarcorhamphus papa King Vulture Vultur gryphus Andean Condor Family Accipitridae 28 25 8 5 Henicopernis longicauda Elanus leucurus Elanus caeruleus Ictinia plumbea Haliastur Indus Haliaeetus vocifer Ichthyophaga nana Gypohierax angolensis Neophron percnopterus Gyps bengalensis Gyps indicus Gyps fulvus Aegypius monachus Trigonoceps occipitalis Circaetus gallicus Terathopius ecaudatus Long-tailed Honey-buzzard White-tailed Kite Black-shouldered Kite Plumbeous Kite White-headed Sea Eagle African Fish Eagle Lesser Fishing Eagle Vulturine Fish Eagle Egyptian Vulture Indian White-backed Vulture Indian Griffon Griffon Vulture Cinereous Vulture White-headed Vulture Serpent Eagle Bateleur 25 14 2 1 2 11 4 1 3 1 8 3 10 4 9 2 24 tn CN CO 116 Spilornis cheela Crested Serpent Eagle 5 10 Geranospiza caerulescens Crane Hawk 4 Circus cyaneus Marsh Hawk 2 80 Accipiter gentilis Northern Goshawk 21 22 Accipiter nisus European Sparrow-hawk 3 Accipiter tachiro African Goshawk 10 Accipiter trivirgatus Crested Goshawk 3 Accipiter badius Shikra 30 126 Accipiter superciliosus Tiny Sparrow-hawk 1 1 Accipiter bicolor Bicoloured Sparrow- hawk 3 4 Butastur teesa White-eyed Buzzard 6 67 Kaupifalco Lizard Buzzard 1 monogrammicus Leucopternis albicollis White Hawk 2 6 Buteogallus anthracinus Common Black Hawk 1 6 Heterospizias Savannah Hawk 1 6 meridionalis Buteo magnirostris Roadside Hawk 44 175 Buteo poecilochrous Gurney’s Buzzard 7 Buteo jamaicensis Red-tailed Hawk 6 8 Morphnus guianensis Guiana Crested Eagle 1 Harpia harpyja Harpy Eagle 1 4 Aquila clanga Greater Spotted Eagle 6 2 Aquila rapax Tawny/Steppe Eagle 16 28 Aquila heliaca Imperial Eagle 1 Aquila chrysaetos Golden Eagle 2 Aquila verreauxi Verreaux’s Eagle 1 Hieraaetus fasciatus African Hawk-eagle 1 3 Spizaetus cirrhatus Changeable Hawk-eagle 7 8 Spizaetus nipalensis Mountain Hawk-eagle 3 11 Spizaetus tyrannus Black Hawk-eagle 2 Spizaetus ornatus Ornate Hawk-eagle 8 41 Stephanoaetus coronatus Crowned Eagle 4 Polemaetus bellicosus Martial Eagle 1 Family Sagittariidae Sagittarius serpentarius Secretary Bird 15 19 Family Falconidae Daptrius ater Yellow- throated Caracara 4 117 Polyborus plancus Common Caracara 17 43 Milvago chimachima Yellow-headed Caracara 1 Herpetotheres cachinnans Laughing Falcon 3 Micrastur semitorquatus Collared Forest Falcon 3 Microhierax caerulescens Red-legged Falconet 188 788 Falco naumanni Lesser Kestrel 22 Falco sparverius American Kestrel 12 Falco tinnunculus Common Kestrel 46 15 Falco chicquera Red-headed Falcon 21 30 Falco columbarius Merlin 4 8 Falco subbuteo European Hobby 3 Falco eleanorae Eleanora’s Falcon 1 2 Falco rufigularis Bat Falcon 1 Falco biarmicus Lanner Falcon 2 36 Falco jugger Lagger Falcon 30 364 Falco cherrug Saker Falcon 1 2 Falco rusticolus Gyrfalcon 7 29 Falco peregrinus Peregrine Falcon 138 287 Unknown Unspecified Raptors 44 109 Order STRIGIFORMES Total (Falconiformes) 789 2,527 Family Tytonidae Tyto alba Barn Owl 2 59 Phodilius badius Bay Owl 1 FamUy Strigidae Otus asio Common Screech Owl 3 Otus cooperi Pacific Screech Owl 5 Otus barbarus Bearded Screech Owl 4 Otus guatemalae Vermiculated Screech Owl 7 3 Otus albogularis White-throated Screech Owl 2 Otus scops Common Scops Owl 73 Otus bakkamoena Collared Scops Owl 5 118 Lophostrix cristata Crested Owl 9 Bubo virginianus Great Horned Owl 7 6 Bubo bubo Eagle-owl 32 4 Bubo africanus Spotted Eagle-owl 1 Bubo nipalensis Forest Eagle-owl 1 Bubo sumatrana Malay Eagle-owl 1 Ketupa ketupa Malay Fish Owl 6 2 Ketupa zeylonensis Brown Fish Owl 2 Scotopelia peli Pel’s Fishing Owl 10 Pulsatrix perspicillata Spectacled Owl 148 97 Nyctea scandiaca Snowy Owl 8 1 Glaucidium brasilianum Ferruginous Pygmy Owl 2 2 Glaucidium passerinum Eurasian Pigmy Owl 29 Glaucidium perlatum Pearl-spotted Owlet 7 6 Glaucidium capense Barred Owlet 7 Glaucidium brodiei Collared Owlet 26 Glaucidium cuculoides Cuckoo Owlet 1 Athene noctua Little Owl 200 Athene brama Spotted Owlet 48 Speotyto cunnicularia Burrowing Owl 8 16 Ciccaba nigrolineata Black-and-white Owl 1 Strix aluco Tawny Owl 3 Asio otus Long-eared Owl 3 Unspecified Owls 30 60 Totals (Strigiformes) 272 676 Estimated Grand Totals of Birds of Prey Imported into the United States Falconiformes Strigiformes Total 1968 789 272 1,061 1969 2,527 676 3,203 Discussion. A return of 71% of surveys sent to one hun- dred and sixty-two Zoological Societies shows a total of 1,828 birds of prey on exhibition. There is evidence pointing to the larger species being popular for this purpose, particu- larly Eagles and Vultures. Buteos also form a firm nucleus. In respect to the replies of the surveys only one reference was 119 made to successful rearing of raptors in captivity— in this case, one White-tailed Sea Eagle. One of the purposes of a zoological collection must be re- search endeavors; captive propagation must surely fall in this category. This is particularly true when speaking of a species such as the Philippine Monkey-eating Eagle {Pithecophaga jefferyi). With published figures of a total wild population of under forty-eight left {Last Survivors, Noel Simon) and with an equivalent zoological population in the United States of America alone of 17% of this total, zoological societies should be expected to participate much more strongly in re- search programs in many different directions, both on a national and indeed an international basis. In the Bald Eagle Project (National Audubon Society, 1963) a total wild population of Bald Eagles (excluding Alaska) of 3,547 birds was projected. Returns from this sur- vey show a total of 132 Bald Eagles on exhibition or 3% of the 1963 total; and of course, in many respects the picture has only become worse since the 1963 count was made. Statistically if one expanded the total of 1,828 returns in this survey from 71% to 100%, a total of 2,574 would be arrived at. Whether in practical circumstances this is accept- able can be questioned, as it is felt most of the major socie- ties did participate in the survey. In the research areas the emphasis for investigation at this time appears to be concerned with the American Kestrel, Peregrine Falcon, and Bald Eagle. Breeding projects and pesti- cides investigation are being heavily researched. It is worthy to note here that much of the research being carried out con- cerning birds of prey is being instigated and perpetuated by private organizations and individuals, falconers playing a major role in a large portion of cases. Statistically if the total of 604 birds returned from 67.6% of the survey was expand- ed to 100%, a total of 893 birds would be arrived at. How- ever, as mentioned before, such an expansion is questionable. In the falconry total some interesting points came to light. It is estimated that 58% of all raptors worked with belong to the Biiteo or Parabuteo genera and this percentage may well be too low. These birds are extremely common and if the majority of falconers are indeed working with this percentage then falconry cannot be considered being harmful to the con- tinuance of the birds of prey. Twenty-eight percent, it is esti- 120 mated, work with falcons. Again, however, between 10% to 12% of this 28% is made up by the American Kestrel, a most common raptorial bird throughout the United States of America, the remaining percentage being spread over a fuller spectrum of falcons. Importation figures demonstrate several points. First the total number of raptorial birds entering the United States in 1969 was approximately triple the total number of 1968. However, this vast increase can be practically explained on an individual species basis as demonstrated below (P— Pet; Z— Zoological; R— Research; F— Falconry). Some Individual Species Importation Totals 1968 1969 Increase Bateleur (Z) 3 24 21 Marsh Hawk (Z & P) 2 80 78 White-eyed Buzzard (P) 6 67 61 Steppe Eagle (Z) 16 28 12 Roadside Hawk (P) 44 175 131 Shikra (R&F) 30 126 96 Ornate Hawk-eagle (Z) 8 41 33 Common Caracara (Z) 17 43 26 Red-legged Falconet (P) 188 788 600 Lagger Falcon (F) 30 364 334 Peregrine Falcon (R&F) 138 287 149 Barn Owl (Z) 2 59 57 Common Scops Owl (Z&P) 73 73 Little Owl (Z&P) 200 200 TOTALS 484 2,355 1,871 The most severe increases noted are in raptors that are commonly utilized for the so-called pet trade. The species that this author would include under that heading carry a symbol “P” and as can be seen, the importation of the Red- legged Falconet has apparently increased 319% in one year. Considerable increases are also noted for the Roadside Hawk, the Little Owl and to a lesser degree, the White-eyed Buzzard and the Marsh Hawk. The importation and sale of exotic or indeed any raptorial bird for pet trade purposes is to be condemned, and this author feels that steps should be taken immediately to pre- vent this commercialism expanding further. 121 It will be noted that the use of the Lagger Falcon for fal- conry purposes appears to have increased sharply; however, it must be stated that importation lists are often confused between the Lagger, Lanner and Saker Falcon and it is highly probable that figures shown for the Lagger Falcon should be more evenly spread over the three species mentioned. Again for zoological purposes increases are noted in the larger rap- tors such as the Steppe Eagle, the Hawk-eagles and the Cara- cara. Importation figures are compiled by the Bureau of Sport Fisheries and Wildlife annually from Form 3-177 which must be filed with the U. S. Customs when foreign wildlife is im- ported. The amount of variance as recorded on these forms is in some cases incredible and it is to the credit of the Bureau of Sport Fisheries and Wildlife that any legitimate totals can be compiled. In this paper some differences will be noted in imported species compared to those recorded as be- ing held for zoological, research or falconry purposes. There are several explanations for this as follows. 1 . Zoological Society did not reply or did not partake in the survey. 2. Bird is held by dealer. 3. Bird was sold for pet purposes or to small travelling zoo or circus. 4. Research facilities did not reply or partake in the survey. 5. Bird held for falconry but not recorded. 6. Bird identified incorrectly. On the other hand, however, it must be realized that in the majority of instances importation figures shown here are in- corporated in the surveys earlier in this paper. Conclusions. A series of surveys has been carried out to gather estimations of birds of prey in captivity in the United States of America. These surveys have included zoological, research, falconry, and importation sources. Replies indicate that there could well be a total of between 4,600/5,800 such birds being utilized or held for various reasons. The former figure of 4,600 is taken from this survey including approxi- mately 1,000 birds imported for what is felt to be the pet trade, while the latter figure is an expanded 1 00% replies from this survey plus approximately 1,000 birds imported for the pet trade. 122 Other points of interest are: A. An equivalent of seventeen percent of the estimated remaining wild population of the Philippine Monkey-eating Eagle are in various zoological collections in the United States of America and it is highly likely that on a worldwide basis an equivalent of at least sixty percent or more would be found in captivity. B. Zoological societies can and should provide more ex- perts to meet the challenges of, and to play more aggressive roles in, research endeavors. C. The majority of zoological specimens are single birds; cooperation between various societies for research projects— particularly rare species— should be given immediate and seri- our consideration, D. At least fifty Andean Condors are in captivity. The situ- ation of this species in the wild should be carefully gauged and birds in captivity used not only for exhibition purposes, but also research efforts. E. Over one hundred Peregrine Falcons are being held for research purposes; this total includes many different sub- species both native and exotic, most of which are in captive breeding projects or pesticide studies. F. A considerable number of raptors are imported for pet purposes. This practice is to be condemned and immediate steps should be taken to prevent further growth of this com- mercial marketing. G. Approximately 70% of all birds of prey worked with for falconry purposes in the United States would appear to be very common h'wds—Buteo, Parabuteo, and Falco sparver- iiis—thus falconry in general does not play a detrimental role with regard to wild raptor perpetuation. H. Falconers are deeply engaged in research efforts with birds of prey. Indeed one can say without hesitation that at this time they form the vast majority. Acknowledgments. I wish to thank the many organizations and individuals who have made this survey possible. Included are: Division of Wildlife Research, B.S.F.W., many universi- ties, zoological societies, private research organizations, state wildlife and natural resource agencies, falconers, researchers, and some animal import firms. To all of these go my sincere thanks for providing information so openly and with so much evident interest. RESEARCH PLANNING CONFERENCE ON PEREGRINES AND OTHER BIRDS OF PREY CORNELL UNIVERSITY, ITHACA, NEW YORK, NOVEMBER 7-9, 1969 - Part 2 by Keith Hodson Zoology Department University of British Columbia Vancouver, British Columbia, Canada [Part 1 was published in Raptor Research News 5(3):92- 95, 1971.] Session of November 7, 1969 (continued) Peregrine Falcons— Breeding Populations (continued) Tom Cade (Upper Yukon River, Colville River, Alaska). Table 2 summarizes Cade’s data for the Upper Yukon River and the Colville River in Alaska since 1951. It is noted that in neither area is there any decline in the over-all number of occupied eyrie sites, but a definite decrease in reproductive success is evidenced. If we base a reproductive success on the number of fledglings per total pairs we observe a decrease from an average of possibly 1.25 in 1951 to an average of 0.93 in 1969 along the Yukon and a decrease from an aver- age of 1.40 in 1952 to an average of 0.79 in 1969 along the Colville River. Probably the most meaningful parameter we can look at is the increase in unproductive birds: they in- creased from 36.3% in 1951 to 53.3% in 1969 along the Yukon River and from 34.4% in 1952 to 60.4% in 1969 along the Colville River. Probably the most distressing evi- dence of reproductive failure are the young between two and three weeks of age which were found dead at the nests for no explainable reasons as yet (10 collected, others decomposed). Weather was not felt to be the cause since the only unseason- able bad spell of weather did not occur until after the young had died. Coinciding with the deaths of these young was an increasing awareness of the breakdown of parental care for the young at these nests and in instances they were observed to not brood or feed young for long periods of time. One 123 124 Table 2. Reproductive Data on Peregrines [T. Cade] A. Along the Upper Yukon River (172 Miles) Datum 1951 1966 1967 1968 Total number of pairs 16-19 17 15(min) 17 Unproductive pairs ca.7/19 3/17 ? 8/15 36.3% 17.6% - 53.3% Eggs or downies/laying - 34/13 - 19/5 pairs (Average) 3.09 3.80 Nestlings/hatching pairs — 32/13 14/7 (Average) — 2.46 2.00 “Fledglings’Vsuccessful 20/12 27/12 - 14/8 pairs (Average) 1.67 2.25 - 1.75 “Fledglings’Vtotal pairs 20/16-19 27/15 14/10 14/15 (Average) 1.05-1.25 1.80 1.40 0.93 Total probably fledged 20 30 21-23 16 B. Along the Colville River (183 Miles) Datum 1952 1959 1967 196? ; 1969 Total number of pairs 32 36 27 32 33 Unproductive pairs 11/32 9/27 16/32 20/33 24.4% 33.0% 33.0% 50.0% 60.6% Eggs or downies/laying 54/17 40/18 50/18 76/26 pairs (Average) 3.18 2.22 2.78 2.92 Nestlings/hatching pairs 56/21 — — - (Average) 2.67 — — — “Fledglings’Vsuccessful 35/14 34/18 34/16 26/13 pairs (Average) 2.50 1.89 2.13 2.00 “Fledglings”/total pairs 35/25 34/27 34/32 26/33 (Average) 1.40 1.26 1.06 0.79 Total probably fledged 44 34 34 26 or less young observed in the process of dying was not being brood- ed at all by the parents. It was hypothesized that altered steroid physiology due to the effects of pesticides could per- haps in turn affect parental behavior in this way. In general, data available since 1951 and 1952 up until 1969 indicate there is no reduction in numbers of pairs of falcons along the Upper Yukon River and Colville River, and 125 it is postulated that even though reproductive success has been significantly decreased, production of young is still ade- quate to balance loss of adults from the population. Pesticide levels and egg shell indices from eggs collected in these areas of Alaska are presented in Table 4. Gerald Swartz (Interior, Alaska). Dr. Swartz presented data based on 8 known traditional Peregrine sites in interior Alaska. In 1969, 7 of these eyries were occupied, but only one was known to have hatched eggs; one other pair aban- doned eggs after two weeks. The successful nest fledged 4 young, and in 1966 from the same site 2 young were fledged. The possibility of weather being a widespread cause of repro- ductive failure in interior Alaska was raised since it was an extremely dry year with no rain between February and August. These dry conditions also led to extremely severe fire and smoke conditions over much of this area for much of the summer, and the effects of this on hunting ability and behavior of the adult falcons can only be guessed at. Clayton M. White (Aleutian Islands, Alaska). [This section is an abstract prepared by C. M. White in 1970— Ed.] This re- ports the first detailed study of Peregrines in the Aleutian Islands, Alaska. The studies were made on Amchitka Island which is situated in the North Pacific between 51 and 52TS1 Latitude and is an island of treeless tundra. This report out- lines my data from May to July 1969, January 1970 and May- June 1970, observations by other investigators recently on the island, and specific observations on Amchitka from older literature. Fifteen pairs and two apparently unmated adults defend- ed territories. Mean distance between pairs was about 5.3 straight-line miles. Nesting success could be determined at only 11 eyries in 1969. I have no data for the other four pair. Fledging success for the 11 eyries was about 1.36 per nest. In seven nests, examined during the incubation period, clutch size averaged 3.14 eggs. Most observed nesting mor- tality was apparently caused by human activity. Fledging be- gan near the end of June and there was near synchrony in fledging dates. Where nest loss occurred there were no renest- ing attempts. About 75% of the prey taken, May through July 1969, was small alcids of five or perhaps six species. Land birds 126 become more common as prey shortly before fledging and on into the fall. Perhaps most of the birds remain on the island through the winter. On 10 January 1970 on a 53 straight-shore line mile flight pairs of adults were found at 3 eyries and 7 sub-adults were counted. On 20 January 1970 on 109 mile flight 13 adults (8 eyrie sites occupied by at least one adult) and 5 sub- adults were counted. The 1970 nesting season showed 19 sites occupied by adults and of 1 2 sites climbed there were 40 eggs or young for an average of 3.3 items per nest. I had to leave the island before data of fledging could be obtained. Extrapolations from Amchitka population density, from ecological variables of Amchitkan and other marine Peregrine populations, and from the physiography of the islands could suggest that 300 breeding pairs inhabit the Aleutian chain. Steven Herman (Interior, California). No birds were found at 18 sites which were checked. From other sources and rumors there may have been another 5 known occupied sites, and probably at least 3 pairs laid eggs. One adult bird was known to have died at an eyrie, and an immature female which appeared to be of the subspecies F. p. pealei was shot in late July in northwest California. Robert Risebrough (Coastal, California). Probably the best known Peregrine eyrie in California is located at Morro Rock. Up until 1967 the young birds were always taken by falcon- ers but from 1967 on the eyrie was closely watched by the Audubon Society. In 1967, 2 young were fledged and in 1968, 3 young were fledged. On Easter Sunday, 1969, the female was found dead and the immediate cause of death was determined to be a prolapse of the oviduct. It was interesting to note that despite the coastal situation of this eyrie, all prey species were determined to be land birds, including Mourning Doves (Zenaidura macroura). Yellow-billed Magpies {Pica nuttalli), and passerines. [Robert Risebrough (Baja California). An egg was collect- ed in 1967 with 500 ppm net weight of organochloride resi- dues. In 1968 (nearby site) one egg was hatched and fledged from this nest. The egg shell was 39% thinner than previous shells. In 1969 at the original site there was one small egg 127 lacking a yolk. Also the same year 22 adults and one imma- ture were seen, seven eyries found, and at least three young fledged.— Ed.] Pesticide levels and egg shell data from material collected in California and Baja California are presented in Table 4. James Enderson (Rocky Mountain Region). Thirty-six out of 50 eyries known in Arizona, New Mexico, Colorado, Wyo- ming and Montana were visited in 1969 and 10 sites were found occupied. Eight sites were successful in producing 1 1 downies, and 4 were known to fledge. One Colorado site was not re-checked to determine if young were produced. Clayton M. White (Utah). Two active eyries were observed in Utah in 1969: at one at least 1 young was raised; at the second a pair of adults was observed. Joseph Hickey (European populations). Table 3 summar- izes reproductive data on French Peregrines. In Switzerland all but 1 of 1 5 eyries were deserted. In Great Britain 1969 data were not available, but a gener- al southward trend of reoccupation has occurred since the banning of chlorinated hydrocarbons. In Ireland the situation is reported to be getting worse, coinciding with no reduction in the use of Dieldrin, DDT, etc. No data are available from Finland, Germany, or Spain. Peregrine Falcons— Migrant Populations Robert Berry (Assateague Island, Maryland). For many years Assateague Island has been known to falconers and others as an area where migrant tundra Peregrines could be trapped in numbers, and in past years an average of 37 birds per year have been taken. In 1968, 30 birds were trapped, and in 1969, 34 birds were captured. In 1969 a total of 146 trapper days were spent on the beaches between September 24 and October 18, and 161 sightings of Peregrines were made. The adult to immature ratio was less than 1:5, or approximately 17% adult. 128 Table 3, French Peregrine Data from Jean-Francois Terrasse 25 October 1969 A. Status at 146 territories visited in 1968. Region Bourgogne Jura South of Massif Central Ecology Near important Not far from Very poor cultivation cultivation agriculture % of territories Deserted 17.5 20 0 Single bird 29.5 23 16.7 Pair 53 57 83.3 Pair with young 17.5 32.7 66.7 Young per pair 1 .66 1.93 2.70 B. Trend in Jura Mountains (66 territories known). Year 1967 1968 1 1969 Number visited 57 61 61 Deserted 7 12 21 Single Adult 11 13 18 Single Immature 0 1 3 Pairs (Adult + Immature) 0 1 1 (Both Adult) 39 34 18 With young 25 20 7 Young per eyrie (per pair?) 2.0 1.93 1.66 James Enderson (Texas Gulf). Comparisons were made be- tween 1964 and 1969 on the number of birds seen while driving the beaches, with an average of 4.9 birds per 100 miles travelled on the beaches and 4.7 birds per 100 miles in respective years. In 1964 the adult to immature ratio of 1 : 1 .38 based on 38 birds was almost twice the ratio of 1 :0.64 for 1969 based on 36 birds. Daniel Berger (Cedar Grove, Wisconsin). Twenty years data at Cedar Grove have indicated approximately a 30% drop in numbers of Peregrines sighted from 1953 to 1967, based on five-year running averages to overcome weather differences. 129 It was stressed that one must keep in mind that there are many variables which can affect such data, including weather, different observers, etc. In 1 969 there were 9 adults, 7 imma- ture, and 3 undetermined. A 54% drop in the numbers of Merlins was also noted. Noel Snyder (South Florida). Snyder reported initiating a new 35-mile survey route in November 1949. Discussion Following the presentation of papers on the Peregrine Fal- con, a discussion led by Dr. Hickey ensued in which the sub- ject of pesticides and PCB’s was dealt with. Table 4 presents the levels of pesticides and egg shell indices given by workers with material from their area analyzed. Dr. Hickey indicated that an over-all reproductive success of North American Peregrines based on the papers presented was about 1 .0 young per occupied site, and a need for more early season data was indicated. He also indicated that resi- due levels in some areas are relatively low and cannot be correlated with population troubles as yet. The most reliable parameter for estimating the effects of pesticides (plus PCB’s) on the reproductive potential of Pere- grines seems to be at present the egg shell index used by Rat- cliffe in Great Britain. Correlation between indices and amounts of DDT and DDT derivative residues have been shown in Herring Gulls (Keith), Double-crested Cormorants and White Pelicans (Risebrough), Bald Eagles (Sprunt), and Prairie Falcons (Fyfe). A 19% reduction in egg shell thickness based on indices seems to be critical in the Peregrine. Indica- tions are that at least in northern Canada, interior Alaska, and in California, populations are probably beyond the criti- cal stage where this thinning begins to affect reproductive success, being 21.7% and 34% respectively (Table 4). The problems of PCB’s have only begun to be explored, but there are suggestions that their effects are about equiva- lent to that of DDT and its derivatives. R. Risebrough indi- cated that the ratio of DDT to PCB’s in San Francisco Bay ranges from about 1 : 1 near shore to 1 : 10 far out. DDT:PCB ratios in Pacific coast birds are given as 16 in Slender-billed Shearwaters {Puffinus tenuirostris) and 6 in the Ashy Petrel {Oceanodroma homochroa), while those for Atlantic coast 130 Table 4. Pesticide and Egg Shell Data T. Cade Pre-1947 Post-1947 Thickness Peregrines Reduction Interior Alaska Egg Index 1.79(N=20) 1.49(N=11) 16% DDE(ppm dry) 106 (N=ll) Arctic Alaska-Canada Egg Index 1.89(N=18) I.48(N=23) 21.7% DDE(ppm dry) 194 (N=ll) Rough-legs Egg Index 2.16(N=48) 2.08(N=16) 8.4% DDE(ppm dry) 4.40 J. Enderson DDE(ppm wet), Peregrine biopsy fat Arctic Alaska 599 (N=9) Mackenzie River 1262[?Ed.l R. Fyfe DDE(ppm wet). Peregrine Eggs Barrens 1 966 4.35(N=6) 1967 7.98(N=4) 1968 21.75(N=1) Ungava 1967 13.31(N=10) Q.C.I. 1966 6.77(N=2) 1968 22.83(N=1) C. M. White Pre-1947 Post-1947 Thickness Aleutians Reduction Egg Index 1.92(N=30) 1.74(N=6) 6% Egg Weight 4.23(N=30) 3.96(N=6) 6.4% DDE(ppm dry) 25.1(N=6) DDE(ppm wet) 3.8 (N=6) R. Risebrough, California and Baja California Mono Rock Baja 1967- 1 968- 1969- Female Peregrine, DDE (of lipid content) (fat basis) 700 ppm (subcutaneous fat, 1000 ppm), PCB 300 ppm (subcutaneous fat 400 ppm) DDE 5 mg/ 1 00 mg sample? 1 egg from egg remnants 34% thinning from pre-war average 1 egg— pre-war thickness average 34, post-war thickness .29, DDE 388 ppm, Dieldrin 1 3.4 ppm, PCB greater 1 egg— post-war thickness .28 131 birds are given as 0.86 for Leach’s Petrels (Oceanodroma leucorhoa), 0.29 for Wilson’s Petrels {Oceanites oceanicus), and 0.68 for Audubon’s Shearwater {Puffinus Iherrminieri). This would indicate a much heavier contamination of the Pacific coast with PCB’s than the Atlantic coast. Short talks were given on the physiology of egg shell thin- ning by R. Risebrough and L. Stickel. One of the puzzling aspects of this thinning process is that only a small amount of DDE and/or PCB is required to cause an initial substantial decrease; greater amounts of these chemicals then cause only a much decreased rate of thinning. By the time levels of DDE have reached 2500 ppm the egg shell thickness has decreased to where there is little more than egg membrane left. Most recent evidence suggests that the calcium must be hit at some sensitive site involved with enzymes, perhaps at the point where calcium is absorbed by the gut. This absorption in- volves active transport by certain membrane proteins, and it has been shown that DDE can affect these proteins. Vitamin D is also considered to be essential in this active transport. Another possible sensitive site is the calcium pump of the shell gland where a calcium binding enzyme is found which is affected by DDT. This enzyme is usually found in excess though; therefore small amounts of DDT would probably not cause a rapid change in egg shell thickness via this pathway. Another enzyme induction theory is concerned with the effects of pesticides on hepatic enzymes somehow involved in calcium metabolism. Needless to say, much work has yet to be done on this subject. The discussion period closed with the decision that if pos- sible a continental-wide Peregrine Falcon survey should be undertaken every five years beginning in 1970. R. Fyfe was to be responsible for Ungava, the Maritimes, Ontario, S. Que- bec, Alberta, S. Baffin Island, Interior Barrens, District of Mackenzie, Yukon Territory and the Queen Charlotte Islands or as much as could be feasibly handled; T. Cade was to be responsible for the Aleutians, arctic Alaska, and interior Alaska; S. Herman and J. Enderson were to be responsible for California, Washington, Oregon and the Rocky Mountain region; and M. Kirven was to be responsible for Baja Californ- ia and Mexico. The details of this survey were to be worked out in later discussions. {This report will be continued.) SEX DETERMINATION IN BIRDS OF PREY BY LAPAROTOMY by Phillip T. Lawson and Earl L. Kittle* College of Veterinary Medicine The Ohio State University Columbus, Ohio 43201 Many problems are encountered in breeding projects in- volving birds of prey, not least is knowing that one does have a male and female. Most of the successful breeding experi- ments have been done with American Kestrels. Since these birds are sexually dimorphic, pairing them has been relatively simple. The larger hawks and falcons, however, are sometimes very difficult to sex by external characteristics. The main criterion that most people go by is size difference, the fe- male usually outweighing the male considerably. Notwith- standing, even the most experienced ornithologists and fal- coners must admit that there are weight overlaps in both sexes. Admittedly, if one has observed his bird in nesting activ- ity he can be sure of sex by behavioral characteristics. On the other hand, if wild trapped birds are being used for breeding, sexing is almost impossible. We were faced with this problem in our current breeding project with Red-tails. Two adult Red-tails were trapped at random and according to body weight and foot size both were males. The birds weighed 37 and 38 ounces and there was no difference in foot size. We decided to perform an exploratory laparotomy and examine the gonads macroscopically to determine sex. We found the 37 ounce bird to be a male and the other a female. The surgical technique is relatively easy. The same ap- proach is used as in caponizing roosters. The poultry people use no anesthesia and do not suture the abdomen. The esti- mated mortality rate in their procedure is about 1%. We do *Present addresses: P.T.L.-7013 Hawks Drive, Olympia, WA 98501; E.L.K.— Courrtry Acre Pet Hospital, 4090 Oxford Trent Road, Oxford, OH 45056. 132 133 not boast that there is no risk in this procedure with birds of prey, but if done properly the mortality rate should be close to zero. We have performed laparotomies on about 30 birds of various species and have lost none. Anesthesia can be accomplished by using gaseous or par- enteral anesthetics. Our anesthetic of choice is halothane, which is a volatile anesthetic and requires a gas anesthetic machine. The only parenteral anesthetic we recommend is Equi-Thesin which is usually injected intramuscularly. The dosage is 0.20-0.25 ml. per 100 grams of body weight (Caudal, 1969). The weight-dosage relationship is very criti- cal when using any parenteral anesthetic since a slight over- dose may kill the bird. In view of this danger, it is very important that the bird be weighed accurately and the dosage calculated accordingly. In our procedure we induce anesthesia by placing a cone connected to the gas machine over the nares and mouth of the bird. The halothane vaporizer is turned to 5%. In using a cone for induction, halothane vapor may get into the eyes causing a keratoconjunctivitis. We recommend that 2-4 drops of a suitable wetting agent be placed in the eyes before con- ing which should prevent damage to the cornea. Ideally, a cone should be fashioned that prevents exposure of the cornea. When the bird’s eye lids close and the mouth can be opened with relative ease, one should be able to pass an endotracheal tube into the larynx. For a bird the size of a Red-tail we use an appropriate sized cat endotracheal tube that is commonly used in veterinary surgery. After the bird is intubated the anesthetic vaporizor is turned down to about 1.5%. This is a relative percentage and will vary with different machines and even individual birds. Anesthesia is monitored by respiration rate, color of muc- ous membranes, and heart rate. These parameters, of course, vary with different species of birds which the anesthetist must determine at the time of surgery. Once surgical anesthesia is reached, the bird is placed on its right side. In most birds of prey, except accipiters, only the left ovary develops. After the bird is secured to the oper- ating table, the down feathers are plucked from an area in front of the thigh about the full length of the thigh and half as long. A skin incision is made over the sartorius muscle. The skin is incised starting ventral to the ilium distally to about mid- 134 way down the thigh. Hemostasis is usually no problem and is controlled easily by digital pressure with a 4x4 gauze sponge. The subcutaneous tissue is bluntly dissected until a blunt type retractor can be placed under the sartorius muscle. The entire thigh is retracted posteriorly exposing the 7th and 8th intercostal space. An incision is then made in the intercostal muscles large enough to insert an otoscope speculum which is used to examine the gonad. The otoscope handle is placed on the speculum permitting one to view the abdominal organs. The abdominal air sac is the first structure seen once in the abdomen. Occasionally the air sac is cut when the inter- costal muscles are incised. This is really no problem since the air sac can be sutured with 4-0 chromic gut at the end of the procedure. The posterior border of the lung is then located by directing the speculum slightly anterio-dorsally over the air sac. Lying just caudal to the lung is the anterior lobe of the kidney. The adrenal gland, a bright yellow structure, can be seen at the anterior medial border of the kidney. The gonad is located just ventral to the anterior lobe of the kid- ney. The ovary appears as a cluster of grapes, the grapes of course representing follicles. The color of the ovary is light yellow to white. The testicle is elongated in shape and is quite pendulous and large when the bird is in season, but will be very small and more closely adhered to the kidney and adrenal gland if the bird is in refraction. The color of the testicles in the birds of prey we have examined was light yellow. Once identification of the gonad has been made, one pro- ceeds with closure. As mentioned earlier the air sac if in- cised can be closed with 4-0 chromic gut. The intercostal space can be closed with 1-0 gut, usually one or two inter- rupted sutures placed around the anterior border of the 7th rib and posterior border of the 8th is sufficient. The skin incision is closed with 3-0 chromic gut using a simple con- tinuous suture pattern. Since avian body temperature is relatively high, gross bac- terial contamination of the wound is ^unlikely. No post- operative complications following this procedure should be expected as long as the bird is well cared for. The down feathers that were plucked from the surgical site will grow back within 6-8 weeks. It is also cosmetically 135 acceptable, since the longer breast feathers and wing will cover the incision. Literature Cited Caudal, C.P. (1969). Surgical Techniques and Anesthesia. In Diseases of Cage and Aviary Birds. Philadelphia, Lea and Febiger, p. 219. RAPTOR RESEARCH FOUNDATION, INC. in care of Biology Department University of South Dakota Vermillion, South Dakota 57069 U.S.A. RETURN POSTAGE GUARANTEED Non-Profit Org. U. S. POSTAGE PAID Vermillion, S.D. Permit No. 37 The RAPTOR RESEARCH FOUNDATION, INC. is a non- profit corporation whose purpose is to stimulate, coordinate, direct, and conduct research in the biology and management of birds of prey, and to promote a better public understand- ing and appreciation of the value of these birds. A major activity to date is the publication of Raptor Research News which has appeared quarterly since 1967 and which is bi-monthly in 1970 and 1971. 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