Accipitriformes/Falconiformes Flashcards
1
Q
What are the five main groups of accipitriformes and falconiformes birds?
A
- Taxonomy:
- 5 families:
- Cathartidae – New World vultures
- Accipitridae – hawks, eagles, kites, harriers, buzzards, Old World vultures
- Falconidae – falcons, falconets, kestrels, merlins, hobbies, caracaras
- Pandionidae – ospreys
- Sagittariidae – secretary birds
- 5 families:
2
Q
Describe the special senses of falconiform and accipitriform birds.
A
- Special Senses
- Generally diurnal, rely heavily on sight for hunting.
- Perceive UV light.
- Each eye has two foveae – temporal for binocular vision, central for monocular vision.
- Exceptions – Andean condors (Vultur gryphus), black vultures (Coragyps atratus) only have a nasal fovea.
- Pectin is plicated in most raptors.
- Raptors lack consensual pupillary light reflexes.
- Sense of smell is poorly developed, except in vultures.
- Most falconiformes have less developed sense of hearing vs owls, except harriers (similar facial disc).
- Taste buds at base of tongue.
3
Q
What is the name and function of the notch in falcon beaks?
Clinically, why does it matter?
A
- Beak
- Sharply hooked, notch behind tip of the upper beak forms tomial tooth for severing neck of prey.
- Preserve tomial tooth when trimming beak.
- Overgrowth of upper beak seen with day-old chick only diets.
- Sharply hooked, notch behind tip of the upper beak forms tomial tooth for severing neck of prey.
4
Q
Describe the feathers of falconiform birds.
What species are sexually dimorphic?
How long does molt take? How is molt induced?
What are stress marks? What causes them?
A
- In general, plumage is not sexually dimorphic except – northern harrier (Circus cyaneus), American kestrel (Falco sparverius), and merlin (Falco columbarus).
- Integrity of primary remiges and tail retrices important for flight performance.
- Tail guards to protect feathers in rehab.
- Imping may be very beneficial in hastening the return of flight after feather damage.
- Molting typically in symmetrical pairs, one feather from right and one from left once per year in early summer after breeding.
- Takes about 6 months.
- Steppe buzzard (Buteo buteo vulpinis) has a chaotic molt pattern.
- Old World vultures molting may take 2-3 years.
- Goshawks and eagles molt only partially each year.
- Induction of molting via manipulation of photoperiod or oral exogenous thyroid hormone.
- 18-20 hours light per day after 4-6 weeks of 10 hours light per day.
- Molt will start within few weeks.
- Onset and rate of molt with thyroxine tends to be rapid.
- Increased ambient temp may speed molt, corticosteroids may slow progression.
- 18-20 hours light per day after 4-6 weeks of 10 hours light per day.
- Stress marks appear as lines across feathers because of interruption in normal flow of nutrients during growth.
- i.e. cysteine deficiency.
- Pinching off syndrome – normal growth of feather for most of normal growth, then blood supply withdraws and feather pinches off in hour-glass presentation.
- Related to viral dz, genetics, quill mites.
- Integrity of primary remiges and tail retrices important for flight performance.
5
Q
Describe the anatomy and physiology of falcon skin.
Do they sweat?
What is a common neoplasm?
Any unique glands?
Is feather plucking an issue?
A
- Skin
- Sweat glands absent.
- Adenocarcinoma and blockage of uropygial gland reported.
- Savanna hawk (Buteogallus meridionalis) – supraorbital aka salt gland.
- Water and electrolyte homeostasis, paired glandular structure with ducts opening in the nasal cavity.
- Harris hawk (Parabuteo unicinctus) – only species showing psychological feather plucking.
- Temporary beak modification technique to prevent self-mutilation in this spp described.
- Seborrhea sicca in eagles, especially feet of captive birds.
- SQ abscesses caused by staph commonly seen.
- Papillomatosis on feet/eyelids sometimes.
6
Q
Describe the talons of various falconiform species.
What is unique about the tendon anatomy?
What is unique about vulture talons? What about osprey talons?
What is the foot arrangement of typical falconiform species?
How is tendon avulsion controlled?
A
- Feet
- Vultures – talons are blunt, do not capture live prey.
- Digital flexor tendons have unidirectional, interlocking ratcheting mechanisms.
- Ospreys (Pandion haliaetus) – highly curved talons, spicules on ventral surface of feet.
- Ability to swivel their fourth digit to rear (semi-zygodactylous).
- All other falconiformes are anisodactyl and perch with three digits forward and one backward.
- Talon of digit 3 has a specialized sharp edge on the medial side, used for feather grooming.
- Talon avulsion – tx by controlling bleeding and covering with protective material i.e. nail polish, and covering with protection and antibiotic powder or talc powder.
- Regrowth of a talon will take up to 6 months.
7
Q
What is the function of the operculum in the falconiform naris?
A
- Nares
- Buteo spp (falcons) and eagles have a bony baffle or operculum to facilitate air flow in the nostrils during high-speed flight.
8
Q
Describe the GI Anatomy of Falconiform Birds?
Is there a crop?
What is the pH of the stomach?
Are there ceca?
Is there a gallbladder?
A
- Gastrointestinal tract
- All falconiformes except the bearded vulture have an esophageal expansions (different from a true diverticular crop).
- Simple stomach, pH 1 in diurnal raptors, capable of digesting bones.
- Ceca is absent or vestigial lymphoid type.
- GB usually present.
- Ventriculus less muscular and koilin layer is more mucoid vs granuvorous birds.
- Ventriculus has a thick lamina densa.
- Liver is bilobed, does not typically extend past keel.
- E. coli, Proteus, Staph, Micrococcus, Corynebacteriu, Bacillus, Strep, Salmonella isolated from lower intestines, cloaca, and fecal samples of healthy raptors.
- All falconiformes except the bearded vulture have an esophageal expansions (different from a true diverticular crop).
9
Q
Describe the urogenital system anatomy of falconiform birds.
How many ovaries and oviducts?
A
- Urogenital system
- Cathartidae, Accipitridae, and Falconidae have two ovaries and two oviducts.
- Unlikely both ovaries are functional.
- No phallus.
- Some falcons and hawks have two ovaries that may be functional but only one oviduct (left).
- Cathartidae, Accipitridae, and Falconidae have two ovaries and two oviducts.
10
Q
What are some unique musculoskeletal adaptations of the genera Falco, Buteo, & Accipiter?
A
- MS anatomy
- Femur and humerus usually pneumatized.
- Genus Falco – two sesamoids in metacarpophalangeal joint, one sesamoid in interphalangeal joint of major digit.
- Two intratendinous ossifications are present in region of carpometacarpus and major digit.
- Os prominens at cranial margin of carpus in Buteo and Accipiter, articulates with distal radius.
- Falcons – tarsometatarsus has a medullary cavity running entire length of bone.
- Hawks and eagles, medullary cavity absent from proximal third of the tarsometatarsus.
11
Q
Describe the appropriate husbandry for falconiform birds.
A
- Housing
- Indoor (mews) and outdoor facilities should be provided.
- Highly migratory species, small Accipiters, southern temperate zone species (Harris’ hawk) cannot tolerate cold.
- Supplemental heat when ambient temp below 0 deg C.
- Eagles, RTHA, goshawks, and most falcons may tolerate extreme cold if protected from wing.
- Accipiters cannot be housed with other species.
- Sexes of merlins and N goshawks should be housed separately, since larger female may kill mate.
- Table of compatible species published.
- Sexes of merlins and N goshawks should be housed separately, since larger female may kill mate.
- Perches
- Falcons – broad, flat perches with artificial turf.
- Buteos and goshawks – elliptical perch, wrapped with rope.
- Multiple perches may be detrimental if hopping with hard landing instead of flying, feet can become bruised.
12
Q
Describe the proper nutrition of falconiform birds.
How much do they typically eat (% BW)?
What is the typical stomach capacity?
Are there seasonal changes in appetite?
When do they cast?
Are there any food species that should be avoided?
What about feeding chicks?
A
- All raptors are carnivores.
- Smaller raptors eat approx. 20% body weight daily, medium 10-15%, large 6-8%.
- Stomach capacity is 40 ml/kg.
- Reduction in food intake observed in warm weather.
- Breeding females should receive calcium and vit D3.
- Probiotics for raptor chicks will reduce enteritis and bacterial overgrowth in first 14 days of life.
- Casts typically 12-18 hours after ingestion.
- Hawks may eat more than one meal before casting.
- Whole prey required.
- Pigeons are a special risk for feeding raptors because of high prevalence of trichomonas and columbid herpesvirus.
- Should be frozen and thawed if feeding.
- Pigeons are a special risk for feeding raptors because of high prevalence of trichomonas and columbid herpesvirus.
- Buzzards – nonspecialized diet, scavengers.
- May encounter long periods of food deprivation between feedings.
- Most are calcium-deficient because they usually ingest meat and viscera.
- Osprey require fish.
- Supplement thiamine.
13
Q
What are the most common nutritional diseases of falconiform birds?
How do those diseases present?
Are there any age- or species-specific concerns?
A
- Secondary nutritional hyperparathyroidism.
- CS similar to other birds.
- Raptors need vit D3, cannot utilize vit D2.
- C:P should be 2:1.
- Seen in free-flying vultures fed china or plastic by parents instead of bone fragments.
- Thiamine deficiency.
- CS – loss of appetite, star gazing, muscle weakness, tremors, opisthotonus, seizures, death.
- Most common in juveniles consuming all-meat diets or piscivorous birds fed thawed fish.
- Tx – IM thiamine, diet supplementation.
- CS may be permanent.
- CS – loss of appetite, star gazing, muscle weakness, tremors, opisthotonus, seizures, death.
- Vitamin A deficiency.
- Pustules in mouth, esophagus, crop, nasal passages.
- Caseous nodules may block salivary glands, syrinx, or area under eyelids.
- Xerophthalmia.
- Pu/Pd, gout, reduced egg and sperm production.
- Hyperkeratosis of plantar surface of feet, predisposes bumblefoot.
- Reduced immune response leads to diseases i.e. asper.
- Pustules in mouth, esophagus, crop, nasal passages.
- Vitamin E deficiency.
- CS – poor muscle function, muscular dystrophy, spastic leg paralysis, degeneration of pipping muscle in neonates, poor hatchability, spraddle legs, muscle twitching, encephalomalacia, incoordination, torticollis, testicular degeneration, infertility and steatitis.
- Fatty liver-kidney syndrome of merlins from feeding of day-old chicks and inbreeding has been reported.
- Accipiters prone to neuro signs and collapse from hypoglycemia.
- Birds with neuro signs fed all-meat diets should be given glucose, B vit (thiamine), vit A, and Ca.
- Young secretary birds (Sagittarius serpentarius) fed on standard raptor diets may suffer Ca:P imbalance because principal food in wild is snakes (high in calcium phosphate).
14
Q
Describe the signs of capture myopathy in secretary birds.
A
- CS – depression, limb paresia or paralysis, hock-sitting, lateral or sternal recumbency and death.
15
Q
Describe the use of injectable anesthetics in raptorial birds.
Are there any drug combinations or routes of administration that should be avoided?
A
- Injectable anesthetics unreliable.
- Ketamine/xylazine has caused deaths, severe bradycardia.
- IV ketamine may cause convulsions, prolonged apnea, cardiac arrest.
- Xylazine alone results in hypersensitivity.
- Tiletamine zolazepam is suitable for anesthesia via parenteral injection.
- Alphaxalone – death in RTHA, high prevalence of sinus arrest and tachycardia.
- Propofol CRI in RTHA – minimal effects of BP, reduced ventilation.
- Prolonged recovery, excitation observed.
- Ketamine or tiletamine zolazepam have been used orally in bait.
16
Q
How long should falconiform birds be fasted prior to anesthesia?
Have any advserse events associated with inhalant anesthesia?
A
- Fast 6-8 hours prior.
- Arrhythmias with isoflurane have been reported in bald eagles.
17
Q
Surgery in wild falconiforms can deem them irreleasable.
What procedures may deem them nonreleasable or provide the potential for complications that may make them that way?
A
- Limb amputation usually results in bumblefoot on remaining foot.
- Scale established as a guide for digit amputation.
- If missing both second digits, one or both halluxes, or all of these, considered not releasable.
- In males, loss of wing may be problematic as wings are used for positioning on the female during mating.
18
Q
What is the most common cause of clinical herpesvirus infections in raptors?
How is it acquired?
What clinical signs are present?
What lesions are present at necropsy?
Describe the inclusion bodies.
How is diagnosis confirmed?
A
- Alphaherpesvirus.
- Columbid herpesvirus- (CoHV-1) most common cause of clinical herpesvirus infections in raptors.
- Results from ingestion of infected pigeons.
- CS – frequently absent, lethargy and anorexia may occur.
- Gross lesions – pinpoint and variably sized tan foci in liver, spleen, BM, miliary areas of lytic necrosis.
- Cells at junction of necrotic foci may contain eosinophilic, IN viral inclusions with distinct halo and hyperchromasia of the nuclear membrane.
- Viral particles detected in droppings of by electron microscopy.
- Viral isolation frequently unsuccessful.
- PCR can confirm.
- Columbid herpesvirus- (CoHV-1) most common cause of clinical herpesvirus infections in raptors.
Terio
19
Q
What species is most susceptible to faconid adenovirus 1? Are other species affected?
Are there any age groups that are particularly susceptible?
How do these birds present?
What lesions are present on necropsy?
Describe the inclusion bodies.
A
- Adenovirus.
- Fatal infections most commonly reported in falcons, also hawks, kites, and owls.
- Falconid adenovirus-1 associated with mortality.
- Widespread in healthy peregrines based on serology.
- Juveniles particularly susceptible.
- Interspecies infection may occur.
- Epitheliotropic and lymphotropic.
- CS – lethargy, anorexia, or death.
- Lesions – hepatomegaly, splenomegaly with discrete white foci.
- Acute hemorrhage in GIT, lungs, repro tract, renal swelling.
- Histo – widespread hepatic necrosis, intranuclear inclusion bodies. Inclusions may be large and fill entire nucleus or be surrounded by a clear halo.
- Classically basophilic but may be amphophilic or eosinophilic.
- Ventricular epithelial cell inclusions may be present in absence of other lesions in falcons.
- Virus isolation, PCR confirm diagnosis.
Terio
20
Q
Describe avian poxviral infection in birds of prey?
Are wild or captive birds more commonly affected?
Are there any unique presentations? If so, what species?
A
- Avian pox virus.
- More common in captive birds.
- Direct and fly or mosquito-mediated transmission suspected.
- Dry form – unfeathered skin and face.
- Considered self-limiting but may result in secondary infection.
- Exudation and crusting frequent.
- Histo – epidermal hyperplasia with edema and pathognomonic large eosinophilic granular cytoplasmic inclusions (Bollinger bodies).
- Poxviral particles can be seen in BB via EM.
- Inclusions more common in superficial layers of epidermis.
- Wet form – extension of cutaneous lesions to mucosa.
- Systemic pox has also been described in a juvenile TUVU.
- Wet and dry lesions.
- Cytoplasmic inclusions.
21
Q
Describe the typical presentaitons of West Nile infections in accipiter birds of prey.
What are the common clinical signs?
Are there any species specific presentations?
What lesions are present at necropsy?
What is the triad of histologic lesions?
A
- Accipitridae:
- Hatch year birds most likely fatal.
- CS – vision impairment, neuro signs.
- Pinched feathers if acute infection is survived for several molts.
- Other gross lesions – patchy beige discoloration of myocardium, white discoloration (fibrin) in fundus of eye, unilateral or bilateral collapse of cerebral hemispheres.
- BAEA – may present with splenomegaly or cardiac dilation with a rounded, beige discolored apex.
- Triad of histo lesions – myocarditis, endophthalmitis, meningoencephalomyelitis hallmark of WNV dz.
- Lymphoplasmacytic inflammation in all sites.
- Extensive cerebellar necrosis with hydrocephalus ex vacuo and parenchymal collapse most commonly occurs in bald eagles and red tailed hawks.
- Usually bilateral, symmetrical.
- Characterized by rarefaction of the brain parenchyma with infiltration by gitter cell and perivascular lymphoplasmacytic infiltrates.
- Multifocal necrosis of exocrine pancreatic cells may be seen.
- Detecting WNV antibodies in CSF supports diagnosis, even in absence of detectable antigen in tissue or negative PCR.
Terio
22
Q
How does West Nile affect falcons and vultures?
A
- Falconidae:
- Similar lesions and antigen distribution as hawks.
- More common in falcons (kestrels, merlins) – fibrinoid necrosis of medium caliber arteries and arteritis in spleen and heart.
- May result in myocardial necrosis and necrosis of brain parenchyma.
- Cathartidae:
- Although many CA condors seropositive, cause of death in only a single juvenile with nonsuppurative encephalitis and concurrent asper.
23
Q
What is the most sensitive tissue for West Nile Virus surveillance?
A
- Determining raptor spp and tissue sensitivity for improved WNV surveillance.
- Feather pulp most sensitive tissue for WNV RNA, kidney second.
24
Q
What is the most prominent finding at necropsy in falcons affected with high pathogenic avian influenza?
What other lesions are present?
What is a common route of transmission?
Has vaccination been shown to be protective?
A
- Avian Influenza Virus. OIE.
- Hemorrhagic pancreatic necrosis most prominent finding in HPAI infected falcons.
- Pulmonary congestion, focal hemorrhage, catarrhal tracheitis has also been induced. Mild multifocal gliosis.
- Virus found most consistently and at highest conc in brain in H5N1 outbreak in Germany 2006.
- Marked nonsuppurative encephalitis primary lesion and cause of death.
- Vaccination of gyrfalcon x saker hybrid falcons with inactivated H5N2 vx has been shown to prevent clinical dz following experimental infection with HPAI H5N1.
- Transmission – wild birds used as prey for hunting falcons, poultry,
Terio
25
Q
What is the etiologic agent that causes Newcastle Disease?
What strain type most commonly present in raptors? What signs does this result in?
What tissues can the virus be isolated from?
A
- Newcastle Disease Virus. OIE.
- Avulavirus genus; Paramyxoviridae family.
- Avian paramyxovirus serotype 1 (PMV1).
- Lentogenic, mesogenic, velogenic strains based on pathogenicity.
- Velogenic most.
- Raptors usually infected via prey.
- Neurotropic and viscerotropic dz.
- Anorexia, vomiting, paralytic ileus.
- Bloody diarrhea.
- CNS signs – ataxia, head tilt, tremors, wing and leg paralysis.
- Torcicollis develops late in the disease.
- Hemorrhage and congestion in proventriculus and resp tract typical in poultry, rare in birds of prey.
- No gross lesions besides swelling of pancreas detected in raptors with neuro signs.
- Lymphoplasmacytic and histiocytic pancreatitis is the microscopic lesion in falcons with viscerotropic form.
- Neurotropic form – nonsuppurative encephalomyelitis.
- Lentogenic, mesogenic, velogenic strains based on pathogenicity.
- Virus can be isolated from spleen, brain, or lungs.
Terio
26
Q
Vultures appear to be resistant to the pathogens they encounter in carcasses.
Why is this?
A
- Vultures appear resistant to pathogens encountered in carcasses.
- May be result of bald head and neck in carcass feeders, low gastric pH, gut microflora inhospitable to certain pathogens, hypothesized differences in specific molecule patterns in pathogens (toll-like receptors).
- African vultures shown to have Ab to anthrax.
- Intoxication and trauma more significant causes of mortality vs infectious disease in these spp.
- May be result of bald head and neck in carcass feeders, low gastric pH, gut microflora inhospitable to certain pathogens, hypothesized differences in specific molecule patterns in pathogens (toll-like receptors).
27
Q
How does Avian cholera present in raptorial birds?
How is it transmitted?
A
- Pasteurella multocida – Avian cholera.
- Serotype 1, 3, 4 most common isolates from eagles, hawks, falcons, owls.
- Transmitted orally or by inhalation or cat bite.
- Pathogenesis – endotoxemia, hyperemia and fibrinous polyserositis.
- Systemic inflammation with intralesional bacteria in acute form.
- Chronic form – oropharyngeal and esophageal granulomas in Buteo hawks.
- Multinucleated giant cells, intralesional bacteria.
- Cytology – bipolar bacteria, confirm with isolation and serotyping.
28
Q
Aspergillosis is one of the most important causes of death in captive raptors.
What risk factors may predispose birds to disease?
What species are particularly susceptible?
What are the etiologic agents?
What lesions are present at necropsy?
Can additional diseases develop as a sequelae?
A
- Aspergillosis – one of most important causes of death in captive raptors.
- Predisposing factors – ambient and husbandry conditions, esp high humidity and temp or dry air with high amounts of dust, or stress from excessive fasting in falconry.
- Trauma and other chronic debilitating conditions (i.e. lead tox) may predispose.
- Gyrfalcons, Accipiter spp, eagles, merlins, and some owls (barn) appear most susceptible.
- Goshawks, gyrfalcons, immature RTHA, golden eagles more likely.
- Raptors from arctic or subarctic climates and ospreys and rough-legged buzzards also of particular risk.
- Caused by inhalation of spores of A. fumigatus, but A. niger and A. flavus may also result in disease.
- Lesions throughout resp tract and other organs.
- Primary asper lesion often in caudal thoracic air sac – where spores first settle.
- Acute asper – miliary lesions in lungs and air sacs, may be related to aspiration of high number of spores.
- Chronic asper – may be restricted to resp tract or affect other organs.
- Granulomas may be in trachea, nasopharynx, air sacs, lung parenchyma, serosa of other organs.
- May lead to obstruction of resp tract and death from asphyxia.
- Air sac thickening, severe fibrinous air sacculitis with abundant fungal growth on air sacs and in pneumatized bones may be seen.
- Granulomas contain numerous septae, dichotomously branching fungal hyphae, positive with PAS reaction and with the Grocott methenamine silver (GMS) stain.
- Fungal culture, PCR, or IHC recommended for dx.
- Chronic asper may lead to pulmonary parenchymal fibrosis and produce secondary right ventricular dilatation and cor pulmonale.
- Predisposing factors – ambient and husbandry conditions, esp high humidity and temp or dry air with high amounts of dust, or stress from excessive fasting in falconry.
29
Q
What is the difference between acute and chronic aspergillus infections in raptors?
Besides air sacs, are other sights colonized?
What diagnostics may indicate active aspergillosis?
What treatment is recommended?
What prevention can be done?
A
- Infection by inhalation of spores.
- Acute infection following inhalation of overwhelming numbers of spores from the environment.
- Chronic infection usually develops following low-level exposure coupled with compromised immune function caused by recent capture, change of ownership, poor ventilation, neonatal and geriatric conditions, corticosteroids, respiratory irritants, or lead poisoning.
- Localized forms involve granulomas in syrinx oe sinuses.
- Resp tract most often affected, but spores may migrate.
- Ocular and skin infections reported.
- Interclavicular air sac most commonly affected in gyrfalcons.
- By time resp signs or weight loss is apparent, usually extensive disease.
- Alteration or loss of voice pathognomonic for syringeal form of asper.
- Dx – heterophilia, monocytosis, rads, deep tracheal or air sac culture.
- ELISA for Buteo spp available.
- Specific conjugates must be made for use in falcons and Accipiters.
- PCR available.
- Protein electrophoresis may show increase in beta and gamma globulins.
- Endoscopy of trachea and air sacs confirms diagnosis and establishes prognosis.
- Tx – oral itraconazole BID for 5 days then once daily for 1-3 months; nebulization with clotrimazole, two 1 hour sessions per day for 4-8 weeks; amphotericin B intratracheally or injected into posterior thoracic air sacs or applied directly to lesions via endoscope.
- Ampho B may also be administered IV.
- Voriconazole may be given orally.
- Liquid form may also be nebulized.
- Fluconazole is not effective.
- A 1:250 dilution of F10 has been used to nebulize raptors alone or in combo with oral itra.
- Birds with severe resp signs have a poor prognosis, surgical removal of localized lesions is needed.
- Prophylaxis – itra for 3-4 weeks recommended during stressful periods.
- Young gyrfalcons, daily administration of itra or terbinafine is initiated and continued until the onset of cooler weather.
30
Q
Describe the presentation of candidiasis in raptorial birds.
Are there any predisposing factors?
Is it more common in wild or captive birds?
What lesions are present?
A
- Candidiasis – Candida albicans.
- Normal in upper Gi healthy individuals.
- Vit A deficiency, prolonged abx treatment, or concomitant infections that disrupt mucosal barriers predispose.
- More common in captive individuals.
- Lesions in oral mucosa, soft palate, upper esophagus, crop.
- May form pseudomembranes (severe thickening and necrosis of the crop epithelium).
- Histo – hyperplasia of epithelium, lymphoplasmacytic inflammation, intralesional yeast and pseudohyphae.
- Highly elongated filamental structures with parallel walls and septal constrictions.
