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Volume 46 | Issue 2 Article 11

1984 Clinical Management of Injured -of-Prey Susan Z. Barrows Iowa State University

Susan E. O'Brien Iowa State University

Follow this and additional works at: https://lib.dr.iastate.edu/iowastate_veterinarian Part of the Ornithology Commons, and the Small or Companion Medicine Commons

Recommended Citation Barrows, Susan Z. and O'Brien, Susan E. (1984) "Clinical Management of Injured Birds-of-Prey," Iowa State University Veterinarian: Vol. 46 : Iss. 2 , Article 11. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol46/iss2/11

This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Clinical Management of Injured Birds-of-Prey

Susan Z. Barrows, BS, DVM* Susan E. O'Brien, DVM**

Introduction stress. Captive birds are more easily restrained In the ruture, veterinarians will play an im­ than wild ones, as they can be grasped from portant role in the maintenance and propaga­ behind while perched on their owners' fist. tion of predatory birds in captivity. This is par­ "Casting" is the method whereby both hands tially attrilbuted to the fact that the mortality are placed on the wings and breast with flexed rate of first year birds in the wild is very high. 1 legs held up to the body.3 Hoods are useful for Falconers are increasingly demanding veteri­ pacifying nervous birds. For those Accipiters nary attention for their trained birds. Numer­ and Buteos not accustomed to hoods, low-light ous zoological parks display birds-of-prey in conditions are beneficial.:1 Unless severely exhibits that routinely need veterinary care. moribund, all birds will resist handling by clen­ For these reasons, veterinary aspects of reha­ ching the talons and biting. A difficult is bilitating predatory are extremely rele­ effectively restrained on its back. 4 Smaller spe­ vant in applied animal medicine today. cies can be restrained in a stockinette; however, Clinically useful aspects of the literature per­ the talons are not immobilized and the append­ taining to raptors are presented in this paper. ages are inaccessible for examination.:1 Non­ Treatments for specific conditions are generally adhesive tape can be used to secure the wings excluded. Methods of anesthesia, diagnostic to the body and to wrap the talons in a closed procedures and management techniques are position. The inexperienced handler is best en1phasized, as are principles of rehabilitation protected from the talons and the of an and release. aggressive raptor by wearing heavy leather Rehabilitating raptors is a time-consuming gloves. task, and this must ultimately be considered in deciding whether treatment is justified. Re­ Physical Exam lease, captive breeding, and euthanasia are Prior to attempting to examine an injured elective for any case admitted to a veterinary raptor, a complete history should be obtained. practice.2The disposition of any predatory bird An accurate determination of body weight is determined by evaluating the extent of in­ should be recorded. This is an important jury or illness sustained, and the capability of assessment of health when done at regular in­ maintaining the bird in an adequate environ­ tervals. ment. The species' status regarding population The bird's body weight and degree of wast­ numbers is also a key factor in the decision. An ing (as determined by palpating the pectoral endangered species is rarely euthanized if an muscles lateral to the keel bone) are useful in alternative, such as captive breeding, is avail­ determining its overall condition. Unilateral at­ able. rophy of the pectorals may indicate loss of function of a wing. 5 Common weights of some Restraint raptors are given in Table 1. Whether captive or wild, proper restraint of Temperature may2 or may not6 be useful. raptors is important in order to minimize Small raptors normally maintain a tempera­ ture of 105-106°F, while large ones seldom *Dr. Barrows is a 1984 graduate of the College of Vet­ rise above 103-104°P when in good health.2 erinary Medicine at Iowa State University. **Dr. O'Brien is an associate professor of Veterinary Marked increase in body temperature in Clinical Sciences. and other species may indicate shock, fever or

Vol. 46) No.2 123 Table 1. Characteristics of common raptors 17 The feet must be assessed and may be thick­ Body Body Wing Raptor Size Weight Length Span ened and/or characterized by draining tracts or Species Classification (g) (em) (em) localized abscesses. Evaluating their tempera­ Red-tailed Hawk (Buteo jamaicensis) large 1,126 46-63 120 Goshawk (Accipiter gentilis) large 978 51-66 110 ture will indicate the integrity of their vascular Red-shouldered Hawk (Buteo lineatus) medium 701 40-61 100 Coopers Hawk (Accipiter cooperi) medium 470 35-51 70 supply. Lesions may explain the loss of toe Broad-winged Hawk (Buteo platypterus) medium 455 33-38 80 Sharp-shinned Hawk )Accipiter striatus) small 140 25-35 50 function Qr a developing arthritis. 2 American Kestrel (Falco sparverius) small 114 23-30 50 Great Horned (Bubo virginianus) large 1,505 63 140 Examination of the musculoskeletal system (Tyto alba) medium 437 46 110 (Otus asio) small 172 25 54 entails palpation of all long bones of the ap­ ( varia) medium 625 41 96 4 3 6 (Nyctea scandiaca) large 1,659.8 63 161 pendages. . . Fractures as well as dislocations Long-earred Owl (Asio otus) medium 240 33 110 Marsh Hawk (Circus cyaneus) medium 510 40-60 100 are apt to be present. These are most accessible with the bird restrained in dorsal recumbency. depression. 2 Auscultation of the heart and air sacs is important a~d shoul9 !lot be over­ Stabilization looked. Supportive therapy is usually indicated prior A predatory bird must maintain its plumage to a diagnostic work-up or surgery. This may in order to sustain flight and maneuverability. be indicated by a packed cell volume (peV) Broken may occur as a result of un­ below 30% and/or a total protein (TP) below 3 suitable housing conditions for those raptors in grams %.7 Fluids, corticosteroids, antibiotics, captivity. 2,4 vitamins, iron and feeding are generally in­ cluded. The weight of the bird is essential if Noting the bird's ability to stand on its own parenterals are to be given. H and close the talons is essential in performing a physical exam adequately. Inability to do so Dehydration is commonly associated with 2 may indicate neurological and/or musculoske­ severe emaciation in raptors. Rehydration is letal damage, as will an inability to raise both necessary prior to feeding a starving bird be­ wings equally. cause metabolic wastes increase in the plasma post-prandially during conservation of body Excessive ectoparasites are a concern, espe­ t1uids. 2 As blood glucose levels fall, free fatty cially in a debilitated raptor. Red mites (Aego­ acids and ketones increase and acetonemia de­ [ius species) are often found around the ex­ velops, causing collapse. 2 A delicate balance ternal ear, the eyes, the mandible, and the between rehydration and feeding must be 2 cloaca. achieved. A careful ophthalmic and oropharyngeal ex­ Ideally, rehydration is achieved using in­ am is a priority. Free blood found in the vitre­ travenous fluids such as 5 % dextrose in water ous is often indicative of permanent ocular to provide energy, or lactated Ringers solution damage. 2 Light adaptation is often hindered in and electrolytes via a stomach tube. 2 Fluids can birds in shock or in birds that have suffered a be administered as an intravenous bolus at collision. Dilation of the avian eye cannot be 2.5-5% of body weight per day.8 Fluids can be aCCOlIlplished using atropine since there is given twice daily for several days until rehydra­ 7 striated muscle in the sphincter. D-tubocurare tion is evident. Subcutaneous fluids can be is an acceptable mydriatic. The color of the given in the wing web or petagium, in the oropharynx may indicate anoxia if blue, and neck, or in the coxofemoral region. The latter shock or anemia if pale. Vitamin A deficiency route may be less desirable in its effectiveness. 2 5 and Candida or Trichomonas infections may be Fluids should be warmed to body temperature manifested as whitish plaques in the oral cavity. for administration regardless of technique The external ear may be blood-filled, indica­ used. 2 ting gunshot or a heavy parasitic infestation. Oral fluids may consist of essential amino Bloody feathers around the vent may indi­ acids, minerals, glucose and B-complex in dis­ cate a raptor that is prone to hemorrhagic tilled water. Egg yolk and/or broth can be sus­ shock. 2 Fungal, viral or parasitic infections pended in electrolyte and dextrose solutions. A may cause diarrhea. Cloacal and lower abdom­ large-bore feeding tube and a syringe work inal palpation allow detection of urate impac­ well for fluid administration orally if care is tion. 4 This is often a sequela to a collision caus­ taken to avoid inserting the tube into the glottis ing neurological dysfunction. at the base of the tongue.

124 Iowa State Veterinarian Shock may be evidenced by the following Table 2. Commonly used antibiotics in raptors signs: staring, disheveled feathers, pale mem­ Drug Dosage, Rate ampicillin 25 - 50 mg/kg TID PO or branes' drooping posture, slowed respiration, 6-10 mg/kg BID IMI9 amoxicillin 50 mg/kg BID POlO increased skin turgor, increased blood pressure chloramphenicol 4-50 me-/ke- TTD PO or 6-10 mg/kg BID 1M 19 (above 50 mm Hg) and slow filling of the digi­ (hlonllllycetin succinatc 3-5 mg/kg BID IMs gentamicin 4 mg/kg BID IM I9 tal veins of the elbow. 'I Profound shock is irre­ minocycline 5 mg/kg BID P0 19 2 neomycin 15 mg/kg PO l2 versible. Corticosteroids are the drug of choice sulphadimidine 500 mg/kg POl2 for shock therapy. Dexan1ethasone, given once daily at 1.0 mg/kg body weight,+ may be ad­ ministered simultaneously with intravenous For short procedures, ketamine hydroch­ fluids or intramuscularly in the pectorals. loride and combinations of ketamine, acepro­ Fluids, heat and a quiet, non-stressful environ­ mazine, diazepam and xylazine can be used in ment are indicated in combating shock. n10st species.> Doses are dependent on body Trauma accounts for a large percentage of fat. 4 In general, larger birds need smaller doses injuries sustained by raptors presented to reha­ while smaller species require larger doses (ex­ bilitation centers. 10 While fracture fixation cluding most owls). 12 If a bird is overweight, as techniques are beyond the scope of this paper, are many captive raptors, the dosage figure is temporary immobilization of fractures should increased (due to increased fat). This may re­ be accomplished early. Light weight casts and sult in a drug overdose. 12 To avoid using too Thomas-Schroeder splints can be applied to ti­ much of an anesthetic, agents can be adminis­ 12 biotarsal fractures. 21 Alternatively, plastic adhe­ tered in divided doses. sive tape can be used for support on smaller Parenterals are most easily injected intra­ screech owls (Otus asio) , American kestrels muscularly, as venipuncture requires adequate (Falco sparverius) and merlins (Falco columbarius). restraint. The pectoral n1uscles, 1 to 2 cm lat­ A femoral fracture may necessitate supporting eral to the sternum, are the recommended in­ the bird in a sling.:2 jection sites.!O In larger raptors, an acceptable Wing fractures are immobilized in a tubular site for intravenous injections is the cutaneous stockinette or by cling gauze and elastic ban­ ulnar vein as it passes over the medial side of dages wrapped around the wing in a figure-of­ the elbow. 4 In smaller species, venipuncture B position. 21 A stockinette will maintain the should be done more cranially lateral to the wing in its natural flexed position and is readily humerus. removed. A figure-of-8 bandage will suffice for During induction, the bird's body tempera­ fractures distal to the elbow. 4 Fractures proxi­ ture must be maintained. Hypothermia devel­ mal to the elbow joint require further fixation ops during avian general anesthesia resulting ofthe bandaged wing to the body with masking in a decreased anesthetic requirement.7 tape. 4 Local anesthetics must be used cautiously as Open wounds require plumage plucking avian species exhibit increased sensitivity to from the affected site, being careful not to tear these drugs. 1'j Procaine is reported to be the 2 the fragile skin. Flushing of the wound with a n10st toxic to wild birds)3,14 but can be used in dilute antibiotic solution and debridement are small doses in larger birds. Ethyl chloride advised. 4 Topical antibiotics are permissible if spray or lidocaine hydrochloride are also ac­ indicated. Some antibiotics commonly used in ceptable in larger species. 1'j raptors and their dosages are given in Table 2. "Ketamine hydrochloride is the safest, most Anesthesia tried injectable drug for sedation (in low doses) As in any species, a preanesthetic fast four to and anesthesia (in high doses) in birds, if good six hours prior to anesthesia is important8 to clinical judgment is used in its application!'7 ensure an empty crop except in the smaller Used at 20-40 mg/kg, it is safe in all raptors species.7 Careful utilization of fasting is sug­ that are relatively stable physiologically.8 The gested for all birds of prey. 7 Due to an in­ effect of ketamine is dose-dependent and varies

creased susceptibility to hypothermia and with the use of synergists. H Advantages of its blood loss, raptors are generally poor anesthet­ use include its wide margin of safety, relative

ic risks. 11 Supportive therapy, if necessary, potency, reliability and availability. H Also, pha­ should be adn1inistered prior to anesthesia to ryngeal and respiratory reflexes are main­

enhance the bird's survivability. tained. Li Disadvantages include lack of analge-

VOL. 46) No. 2 125 sia, variable effect on members of the same Diazepam can be given with ketamine in 4 H species • and a fairly prolonged recovery time, diurnal species to accomplish general anesthe­ 7 often characterized by violence. ,8,15 Wrapping sia. Dosages include 35 mg/kg ketamine and a bird in a towel during the recovery period 1-1.5 mg/kg diazepam. 12 Owls, in general, re­ will help reduce struggling. quire smaller doses. Barred owls require only half the dose as required for great-horned owls. Synergists used with ketamine will minimize the disadvantages of using the agent alone in Inhalant anesthetic agents are generally raptors. Xylazine hydrochloride, at 0.5 to 2.0 safer than are the injectables. These allow for a mg/kg in combination with ketamine, reduces more rapid induction and recovery in birds a violent recovery.4,8 Differences in these drug than in . [4 Induction can be achieved dosages for various raptor species are given in by an injectable drug combination as described Table 3. Using a ketamine/xylazine combina­ above or by an inhalant. Gaseous anesthetics tion, anesthesia lasts from five to 15 minutes are commonly used for maintenance. Nitrous with recovery generally in 30 to 40 minutes. oxide, methoxyfluorane and halothane are ac­ u s Higher doses can increase anesthesia up to one ceptable inhalants in raptors. , Regardless of hour with proportionately increased recovery the inhalant agents used, an endotracheal tube times. A slight decrease in heart and respirato­ should be used. ry rates is expected using this anesthesia regi­ Atropine, at 0.5 mg/kg intramuscularly, will me. B reduce airway secretions if administered five minutes prior to induction. It will not result in

pupillary dilation in birds. 7 Table 3. Recommended Anesthetic dosages in raptors10 Raptors Amount of ketamine (cc)*/bird Anesthetic emergencies call for oxygen with Kestrel, Saw-Whet Owl 0.03 intermittent positive pressure ventilation and Screech Owl, Boreal Owl 0.05 Short-eared Owl, Long-cared Owl 0.06 respiratory stimulants. Cervical air sac inci­ Broad-wing Hawk 0.06 Merlin, Sharp-shinned 0.06 sions and tracheostomies can be lifesaving Cooper's Hawk, Barred Owl 0.10 Goshawk - Male 0.10 techniques in birds with upper airway obstruc­ Female 0.15 Peregrine, Prairie - Male 0.07 tions. Female 0.12 Great-grey Owl 0.10 During recovery, wrapping the pati~nt loose­ Great , Snowy Owl 0.15-0.25 (marginal)** , Golden eagle 0.15-0.20 ly in a towel and placing it in sternal recum­ Gyrfalcon - Male 0.15 Female 0.15 bency in a semi-dark, quiet room is beneficial. Red-, Swainson's Rough-leg, Ferru- Body temperature can be maintained by plac­ ginous 0.10-0.15 0.15 ing a heating pad under the bird. *Solution containing 100 mg/cc; mix with an equal volume of-Rompun (20 mg/cc). These doses have been empirically derived for each species as indicated. They are expressed as "cc/bird" not "cc or mg/kg:' **for Great Horned owls and Snowy owls use intravenous sodium pento- barbital: Diagnosis - For owls between 1100 and 1400 grams, give 35-40 mg (0.6 cc) - For larger owls up to 2200 grams, give 50-55 mg (0.8 cc) Pentobarbital is supplied as 1 grain (64 mg)/cc solution. Hematology Hematological parameters are useful in Nocturnal raptors metabolize anesthetic assessment of the physiological condition of 3 doses of ketamine/xylazine combinations faster predatory birds. ,5,7 A simple packed cell vol­ than diurnal species. B Hawks, eagles and ume (PCV) and total protein (TP) indicate falcons tolerate 25-30 mg/kg body weight cou­ anemia, as well as the hydration status of a pled with 2 mg/kg xylazine intravenously. 4 raptor. Those birds with a PCV less than 20 % Nocturnal birds-of-prey, including some owls, are considered anemic. 7 Dehydration is evident are best anesthetized with 15 - 20 mg/kg ke­ if the PCV rises above 55 % .7 A pev less than tamine, not exceeding 10 mg/kg in the barred 30% and/or a TP of 3 gm% or less indicate the owl (Strix varia). 4 This allows for approximately need for nourishment or supportive theray. 8 30 minutes anesthesia in these species. Great­ Suggested blood sampling sites in raptors in­ horned owls (Bubo virginianus) and owls clude the cutaneous ulnar vein where it crosses (Nyctea scandiaca) , however, do not tolerate ke­ over the ventral aspect of the distal humerus, tamine/xylazine combinations well. Instead, or the brachial vein at the midshaft of the hu­ intravenous sodium pentobarbital can be used merus. 4 Normal hematocrit values are given in with them at a dosage of 0.8 gm/kg. 10 Table 4.

126 Iowa State Veterinarian Table 4. Packed cell volume (%), total protein (gm/dl), and difIerentialleukocyte count (%) of selected healthy captive raptors*20 # Birds PCV TP gm/dl # Birds Heterophil Lymphocyte Monocyte Eosinophil Basophil Bald Eagle 3 43.3 4.6 4 61 23 8 7 1 (4.5)** (0.4) (4.3) (5.5) (3.2) (2.2) (0.8) Golden Eagle 41. 3 4.4 60 27 7 5 1 (4.6) (0.4) (10.1) (7.5) (2 7) (2.8) (0.6) Red-tailed Hawk 10 44.6 4.3 10 35 44 6 13 2 (2.6) (0.5) (11.1) (8.9) (3.2) (3.8) (1.3) Great-horned Owl 11 43.3 5.1 11 47 27 9 16 1 (2.9) (0.6) (10.7) (7.0) (3.6) (9.3) (1.2) Barred Owl 10 41.3 4.8 10 29 51 11 8 1 (2.2) (0.4) (8.6) (9.7) (3.9) (2.8) (1.3) *Based on duplicate, preprandial samples taken two weeks apart. **Population standard deviation.

Differential counts are good indicators of the Endoscopy health status of a predatory bird but are not Laparoscopy, a form of endoscopy, is the necessarily diagnostic. Normal values are easiest and most practical method used to sex given in Table 4. In general, raptor cell counts predatory birds. Other organs may also be are similar to those of other avian species. 16 viewed. In general, heterophils increase as a result of This is accomplished using an endoscope, stress states, such as infection, riboflavin defi­ such as the kind used in human medical prac­ ciency, and cold.!() Eosinophils increase with tice. A 4 mm and a 2.7 mm diameter telescope parasitic infections, hypersensitivity reactions are adaptable for this use. 6 Reliable anesthesia and frequently increase with sp. is required6 and a light dose of ketamine is gen­ infections in great-horned owls.]b A blood erally adequate. smear should always be evaluated in light of The patient is restrained in right lateral re­ the presence of blood parasites, including cumbency with the legs pulled back and the Leucocytozoon sp., Plasmodium sp. and Haemopro­ wings up. A 1 cm incision is made in the skin teus sp. between the last two ribs, and a small wound retractor inserted to maintain an opening and Radiology reduce hemorrhage. 6 An endoscope with a light Whole body radiographs are most diagnostic source is directed into the caudal thoracic air in accurately appraising the musculoskeletal sac by piercing a thin septum cranioventral to system.4.:i The body wall must be cleaned off the incision site. The abdominal organs can well to avoid misinterpretations. Lateral and then be viewed through the scope. Once the dorsoventral views on ultra-detail cassette film procedure is finished, the skin is sutured with 5 are most conclusive. Anesthesia is often man­ 3-0 catgut and an antibiotic ointment applied. 6 datory if a good radiograph is to be obtained, Some subcutaneous emphysema may occur but must be administered cautiously in a debi­ and is acceptable. 4 litated bird. This quick and simple procedure allows vi­ Radiographs commonly reveal unpalpable sualization of the following: 1) caudal thoracic fractures of long bones, shoulder separations, air sacs: lungs, thoracic cavity, cranial edge of lumbosacral joint injuries, air sacculitis, cloacal the kidneys and adrenals; 2) cranial thoracic impactions, hepatomegaly, Aspergillus granu­ air sacs: liver and stomach; and 3) abdominal lomas, enlarged kidneys, peritonitis, foreign air sacs: kidneys, adrenals, gonads, intestines, bodies, and hernias. 4 Secondary osteoporosis is spleen, oviduct and vas deferens. 6 often evident, especially in young birds main­ tained on a diet with an improperly balanced calcium/phosphorous ratio. Whole bones of a Table 5. Blood chemistry profiles in raptors16 raptor's prey are a normal radiographic finding Golden Bald Red-Tailed Harris # Birds/samples Eagle Eagle Hawk Hawk in the crop and proventriculus. per Bird 5/2 4/2 4/2 3/2 Glucose (mg/dl) 250-408 285-400 312-412 305-400 Total Protein (gm/dl) 2.5-3.9 3.0-4.1 3.3-4.5 3.9-5.2 Serum Chemistries Albumin (gm/dl) 1.0-1.4 0.8-1.6 0.9-1.2 1.0-1.2 SGOT (mU/ml) 95-210 153-370 113-180 As these tests are expensive and often incon­ SAP (mU/ml) 15-36 23-30 45-90 64-130 LDH (mU/ml) 320-690 250-580 470-775 245-400 clusive, they are not routinely used in evaluat­ Uric Acid (mg/dl) 4.4-12.0 5.5-14.8 7.5-17.8 8.8-21.5 Creatinine (mg/dl) 0.6-1.2 0.4-1.0 0.5-1.2 0.7-1.5 ing raptors on admission to a veterinary prac­ T. Bilirubin (mg/dl) 0.3-0.5 0.2-0.5 0.5-0.6 0.5-1.2 Cholesterol (mg/dl) 100-190 150-242 100-150 150-280 tice. Normal values for some species are listed Calcium (mg/dl) 7.4-9.5 8.2-10.6 8.4-10.0 8.5-10.0 in Table 5. Phosphorous (mg/dl) 1.9-3.6 2.4-3.2 1.8-4.1 3.0-4.4

Vol. 46) No. 2 127 Bronchoscopy, another form of endoscopy, is Table 6. Amount of food eaten by raptors in the wild17 Species % BW Consumed/Day Grams Consumed/Day a useful tool in determining the status of trau­ Black Vulture 6- 11 200 matized birds, for monitoring treatments (i.e., Turkey Vulture Coopers Hawk Spring, Summer 16.03 69.5 for aspergillosis) and for eliminating disease Fall, Winter 19.7 80.0 Red-tailed Hawk Spring, Summer 8.6 101 carriers (i.e., of tuberculosis) in early stages of Fall, Winter 10.7 135 Red-'shouldered Hawk Spring, Summer 11.2 65 the disease process. It allows visualization of American Kestrels Spring, Summer 17.0 27 Fall, Winter 25.3 41 the pharynx, glottis, and syrinx in Spring, Summer 7.2 85 Screech Owl Spring, Summer 10.3 14 birds. In larger species such as hawks and Fall, Winter 25.4 eagles, one can visualize the bronchi. Barred Owl Fall, Winter 11.8 67 Barn Owl 10-12 67* Reliable anesthesia is also required for bron­ Long-Eared Owl 10-12 67* $nowy Owl 10-12 67* choscopy. If the bronchoscope is to be passed Goshawk 10 125 Broad-Winged Hawk 11 65 into the large bronchi, the caudal thoracic air Marsh Hawk Spring, Summer 12 6 Fall, Winter 19 42 sac must have been previously opened. Sharp-shinned Hawk 23.3 39 *No data available-these are estimates based on the size of the owl.

Accommodations the diet is kept as close as possible to that in the Raptors, like rnust wild birds, require a wild. Anl0unts of food required by some spe­ warm, semi-dark environment to reduce cies are given in Table 6. In general, rapiors stress. Federal law requires that all wood sur­ eat 10% to 20 % of their body weight in food 4 faces of cages be coated with varnish or shellac per day. ~ Whole mice, chicks') and quail are good food sources. These can be frozen and to prevent disease propagation in the wood. 17 A perch wrapped with sisal rope or Astroturf thawed as needed. A severely debilitated bird should not be given the bones and fur as they should be provided to prevent bumblefoot. 5 The size of the perch n1ust accommodate the may not be regurgitated. Force-feeding can be talons of the bird adequately or pressure point attempted initially; however, the birds should lesions develop on the central tarsal pads. start self-feeding within a few days. A Woodchips can serve as a source of aspergillosis should be regurgitated in 24 hours. 'j Fresh wa­ and are best avoided.·J Cages should be disin­ ter should be made available free-choice to all fected daily in the summer and less frequently raptors whose feet are not in ball bandages. If whole are not available, a suitable in the winter. 17 fat-free diet containing raw beef heart, liver Various species can be housed together pro­ and chicken necks should be given, mixed with vided adequate space and food are available. 17 50 % bone meal, 40 % powdered skim milk, Table 1 provides some size characteristics for 5% iodized salt, and 5% protein powder several raptor species which can be used to de­ moistened with cod liver oil or wheat germ termine the space needed for housing. If trau­ oil. 17 matized' a raptor is best housed individually in a cage. Rehabilitation of recuperating raptors Rehabilitation can be accomplished in layer group pens where In evaluating raptoI's fur potential release, more exercise is possible. Large, cardboard there are three considerations: a bird's health, furniture boxes suffice for indoor cages if its relationship with man, and the locality and wooden ones are not accessible. If no sunlight time of year in which the release will occur. 18 is available, vitamin D 3 should be supple­ The assessment of health must include the 17 mented. A minimum size for enclosing a red­ general condition of the bird. Pectoral mass, tailed hawk (Buteo jamaicensis) or similarly-sized body weight and hematocrit values are useful l7 raptor might be 1.5 m X 1.5 m X 1.5 m. in making the overall evaluation. Injuries pre­ A captive raptor's tail feathers are best main­ viously sustained must be resolved well enough tained in a tail sheath constructed of a manilla so flight capability is not impaired. The ability folder or x-ray film taped to the tail base with to well in a straight line does not guarantee masking tape. This provides excellent protec­ the bird can maneuver properly to capture its tion to those feathers which are essential in prey.5,18 Wing injuries are difficult to assess, normal flight and maneuverability. 4 and they impair maneuverability. 18 Health in birds-of-prey is best maintained if The species under consideration will deter-

128 Iowa State Veterinarian mine the amount of decreased maneuverability coverable loss of neurological function of a permissible. Sedentary birds such as buzzards foot, and total loss of sight are situations that (Buteo buteo) are more tolerant of impaired usually warrant euthanasia. Loss of both first flight capability than aerial hunters and mi­ and hind digits in males of any age (excluding grating species such as the Peregrine falcon endangered birds) generally dictate euthana­ (Falco peregrinus). IH sia.': In arboreal species, especially males, Raptor species also vary in their need for physical adjustment to the loss of a wing distal perfectly maintained feet. In general, birds-of­ to the metacarpus is difficult. ~ Osteomyelitis of prey tolerate foot injuries if they do not lose the the tarsometatarsus of both feet calls for eu­ functional capacity of their first or hind digit. 18 thanasia in most cases. ~ Involvement in one Buzzards are better able to survive with in­ foot of a female may be tolerated if she is to be jured feet than goshawks (Accipiter gentilis) and used in a breeding program. Joint capsule in­ kestrels or the specialized falcons 18 that depend fections subsequent to bumblefoot and septic on their feet to capture and hold their prey arthritis in both feet will not be conducive to while they consume it. survival in any raptor species. 2 Age is also important to survivability of a Raptors exhibiting neurological abnormali­ releasable bird-of-prey.2,18 Older birds are bet­ ties including head tilt and improper balance ter able to compensate for the lack of function should be euthanized if unresolved in eight of an appendage or sense organs and to cope weeks. 2 Failure to regain lost intestinal motility with environmental stress. The sex of the bird in four weeks carries a grave prognosis,2 and plays a role in its survival after the loss of some euthanasia should probably be elected in these facilities. cases. Doubtful prospects should be flown first on a A severe sinusitis, malignant tumors, behav­ tether and flight capabilities evaluated. The ad­ ioral problems and major irreversible nutri­ vice of a trained falconer should be sought in tional deficiencies significantly decrease the these cases. survivability of raptors in the wild. Human relationships and behavior are ex­ Many considerations must be given to the tremely important in judging a candidate for release of raptors undergoing rehabilitation. release. 5 Wild birds that lose their fear of hu­ The decision to euthanize a bird must be based mans are less apt to seek food on their own. 18 on its ability to survive either in the wild or in Imprinting will sufficiently diminish the breed­ captivity or on its adaptability to a breeding or ing potential of a raptor in the wild. "Hacking educational project. back;' the process whereby food is set out for a period of time and gradually withdrawn, may Conclusion

facilitate the bird's readjustment to the wild. 18 Overall, the practitioner must first decide Release early in the day allows the bird plenty whether he or she is capable of adequately of daylight to seek food and shelter in the en­ managing a raptor, then consider if he or she vironment. has the ability to rehabilitate the recovering Some species will not survive well if released bird. Only then can the treatment of birds-of­ in the winter.:J In general, red-tail hawks, prey be undertaken in a meaningful way. eagles, great horned owls and screech owls do well, provided they have been acclimated to outdoor temperatures for approximately two References weeks prior to their release. 4 Locality is an im­ 1. Cooper JE: Veterinary Aspects of Captzve Birds of Prey. portant consideration, especially in releasing England Strandfast Press, 1978. young birds. 1H 2. McKeever K, Rannie WF: Care and Rehabilitation of Captive breeding is an alternative to release, Injured Owls. Canada, WF Rannie, 1979. 3. Halliwell WH: Restraint and Handling of Birds of as is euthanasia. The details of breeding rap­ Prey, in Fowler NIE (ed): Zoo and Wild Animal Medi­ tors in captivity are beyond the scope of this cine. , WB Saunders, 1978. paper. 4. Reoig PT, Duke GE: Raptor Research and Rehabili­ Overall, the decision to treat predatory birds tation Program at the College of Veterinary Medi­ cine. Veterinarian 18(1): 27 -34, 1978. is often species-dependent. There are situations 5. Gilbert TL, Eggar EL: Management of Casualty that mandate euthanizing even the most en­ Birds of Prey. Iowa State University Veterinarian. dangered species. Loss of an entire foot, unre- 44(2):99-103, 1982.

VOl. 46) No. 2 6. Boetcher M: Endoscopy of Birds of Prey in Clinical 14. Klide AM: Avian Anesthesia. Veterinary Clinics of Veterinary Practice, in Cooper jE Greenwood AG 3(2):175-185, 1973. (ed): Recent Advances in the Study of Raptor Diseases. 15 Mattingly BE: Injectable Anesthesia. for Raptors. London, 101-104, 1980. Raptor Research 6(2):51-52, 1972. 7. Hartsfield 8M: A Review of Avian Anesthesia. South­ 16. Ivins GK, Weddle CD and Halliwell Wj: Hematol­ western Veterinarian) 35(2):117-125, 1982. ogy and Serum Chemistries in Birds of Prey, in 8. Haigh jC: Anesthesia of Raptorial Birds, in Cooper Fowler ME (ed): Zoo and Wild Animal Medicine) Phila­ jE, Greenwood AG (ed): Recent Advances in the Study of delphia, WB Saunders, 1978, pp. 286-290. Raptor Diseases. London, 61-66, 1980. 17. Hayes MB (ed): Wildlife Care and Rehabilitation. 9. Schulz T, Sedgwick C: Veterinary Care of Birds of Brukner Nature Center, Troy, 1980. Prey of . California Veterinarian 4: 18-24, 18. Cooper jE: The Assessment of Health in Casualty 1979. Birds of Prey. The Veterinary Record 106:340-341, 10. Redig PI: A Clinical Review of Orthopedic Tech­ 1980. niques Used in the Rehabilitation of Raptors. Annual 19. Sawyer BA: Bumblefoot in Raptors, in Kirk RW Proceedings ofthe American Association ofZoo Veterinarians. (ed): Current Veterinary Therapy VII. Philadelphia, WB 8-11, 1982. Saunders, 614-616, 1983. 11. Paddleford R: Anesthetic Management for Birds of 20. Durham K, Redig, PT: Hematology as a Diagnostic Prey, in Fowler ME (ed): Zoo and WilJ Animal Animal Tool in the Assessment of Injured Wild Raptors. Medicine. Philadelphia, WB Saunders, 1978, p. 244­ Proc. International Symposium on Diseases ofBirds oj Prey. 246. London, 1981. 12. Redig PT, Duke C E: Intravenously Administered 21. Garcelon D, Bogue G: Raptor Care and Rehabilitation. Ketamine Hel and Diazepam for Anesthesia of Rap Alexand<:>r T'lnclsay j r. Museum, Walnut Creek, Ca­ tors. JAVMA 169(9):886-888, 1976. lifornia. 13. Cooper jE: First Aid and Veterinary Treatment of Wild Birdes. Journal of Small Amimal Practice 16:579­ 591, 1975.

130 Iowa State Veterinarian