WILDLIFE MED - Birds

• Passerines


  • Large diverse order, encompassing almost 60% of all living bird species
  • Dominant land birds globally with 5100 species and 59 families
  • Perching feet—3 forward toes and 1 hind toe = ANISODACTYL
  • Most advanced order, intelligent, and adapted to a wide variety of niches
• Passerines' foraging behavior can predispose them to injuries
• Passerine injuries


  • Wrens caught in glue traps
  • Doves collide with windows, rupturing their distended crops
  • Aerial insectivores/humming birds have shoulder injuries
• Passerines CANNOT modify their behavior to survive with a deficit
• Galliformes


  • Composed of 7 families with 256 species, 4 of which are native to NA
  • Adults are sexually dimorphic; some species have unique skin appendages on their head and neck
• Common Galliformes species


  • Pheasants
  • Quail
  • Grouse
  • Partridges
  • Ptarmigans
  • Praire chickens
  • Turkeys
  • Peafowl
  • Jungle fowl
• Captive management of passerines and galliformes

  • House adult birds individually; social behavior of many species is seasonal or nonexistent, and pecking orders exist even in captivity
  • Don't use wired cages = damage feathers
  • Housing should be large enough that bird can maintain normal posture without injury and feather damage
  • Supplemental heat is required for nestling birds
  • Young birds may be safely housed with conspecifics and/other birds of similar type, size, and age
  • Nests of cavity nesting species should be placed underneath a 'hide box', leaving enough head clearance for easy access
• Examination of passerines and galliformes

  1. Begin observation at a distance; allows you to evaluate respiration, attitude, and posture of the bird

  2. Observe bird's activity and response to noise and motion

  3. Check for abnormal respiration conditions like open-mouth breathing, rapid and shallow breathing, breathing with effort, irregular/gasping patterns, and moist or harsh respiratory noises

  4. Evaluate neurological signs like seizures, head tremors, and abnormal body postures

  5. Check droppings for feces and urates; perform fecal smears and flotations on all underweight birds

  6. After weighing the bird, assess the body condition by palpating the keel
• Keel


  • If you can pinch the keel = lean to underweight
  • If keel is prominent = emaciated
• Mycoplasmal conjunctivitis


  • Causative agent: Mycoplasma gallisepticum
  • Commonly affects immature horse finches, American gold finches, and blue jays
  • Transmission: Vertical and Horizontal
  • Clinical signs: conjunctivitis, periocular inflammation, dyspnea, sinusitis, and ocular discharge from 2ndary bacterial conjunctivitis
  • Diagnosis: PCR and culture
  • Treatment: Rinsing eyes with saline followed by topical application of ophthalmic drops; Systemic Tx – Tylosin tartrate
• Salmonellosis


  • Causative agent: Salmonella typhimurium
  • Spread at winter bird feeders; reported in Pine siskins and finches
  • Clinical signs: sudden death, ataxia, poor flight, ingluvitis, crop abscess, enteritis, weakness, and emaciation
  • Transmission: Feco-oral
  • Diagnosis: Necropsy and culture
  • Treatment: Long-term antibiotic therapy
• Bacterial sinusitis


  • Commonly seen in hand-reared passerines, from food entering the URT
  • Clinical signs: Facial sinuses distend with caseous material and/or mucoid fluid; swelling may distort the face and upper palate
  • Treatment: Systemic antibiotics with nasal flush
  • Note: Right and left nasal sinuses do not communicate, so drops must be applied to both nares if infection is bilateral
• Pox virus


  • Causative agent: Avipoxvirus
  • Commonly seen in doves, crows, thrushes, and finches
  • Present 3 forms: Cutaneous (dry pox), Neoplastic, and Diphtheritic
• Avian influenza rarely causes morbidity or mortality in passerines and wild Galliformes
• Candidiasis or Thrush


  • Causative agent: Candida albicans
  • Normal GI flora of most birds – commensal
  • Clinical signs: Overgrowth in young birds, Beak deformities in hummingbirds, Vomiting, anorexia, weight loss, diarrhea, crop stasis
• Aspergillosis


  • Causative agent: Aspergillus fumigatus
  • Usually, 2ndary to immunosuppressive condition and rarely diagnosed ante-mortem
  • Clinical signs: Weight loss, anorexia, vomiting, diarrhea, large buffy coat, and sometimes dyspnea
  • Diagnosis: Serology and endoscopy
  • Treatment: Terbinafine + Voriconazole
• Ectoparasites of passerines and galliformes

  • Chewing lice (Order Phthiraptera)
  • Ticks (commonly Argas spp.)
  • Flies (Order Hippoboscidae)
  • Scaly leg mites (Knemidokoptes jamaicensis)
  • Skin mites (Ornithonyssus spp.)
  • Feather mites (Dermanyssus)
  • Follicular mites (Harpyrhynchus)
• Trematodes infecting passerines outside GI tract

  • Collyriculum – encyst in the skin
  • Diplosomum – migrate to ocular conjunctiva appearing as conjunctivitis
• Treatments for endoparasites


  • Praziquantel for Cestode and Intestinal trematode infection
  • Loperamide for Acanthocephalan infection
  • Fenbendazole, Ivermectin, Pyrantel pamoate for Nematodes
• Coccidiosis


  • Causative agents: Isospora and Eimeria
  • Clinical signs: Diarrhea (w/ or w/o blood), anemia, emaciation, dehydration
  • Treatment: Sulfadimethoxine, Toltrazuril/Ponazuril
• Trichomoniasis


  • Causative agent: Trichomonas gallinae
  • Results in lesions in the upper GIT of doves; less common in passerines and galliformes
  • Clinical signs: white, caseous exudate on oral and esophageal mucosa; dysphagic birds present emaciated condition with distended malodorous crops
  • Treatment: Carnidazole and other nitroimidazoles
• Tetratrichomonas gallinarum


  • Associated with sinus infection in Turbidae and Mimidae families
  • Clinical signs: Sinus distention, nasal discharge, periorbital inflammation, blepharosis, chemosis
• Cryptosporidium-like disease


  • Reported in Cliff swallows
  • Presents similarly to T. gallinarum and M. gallisepticum infections
  • Treatment: Paromomycin
• Non-infectious reasons for passerine and galliform presentation

  • Predator attacks
  • Head trauma
  • Entrapment of adhesives
  • Toxins (cedar waxwings, invasive berries)
  • Fractures
  • Curled digits
  • Wounds
  • Beak injuries
  • Crop rupture
  • Domestic species
• Phlebotomy


  • Blood collection = right jugular vein, located in the dorsal apteric region
  • Pigeons and doves lack this region = difficult jugular access
  • Brachial vein = best accessed under anesthesia to avoid hematoma formation
• Euthanasia

  • Indicated for birds whose injuries carry a poor prognosis, whose disease may put other birds at risk, or whose injuries will require extended treatment and care
  • Euthanize by IV sodium pentobarbital or IM midazolam
• Release


  • All juvenile and adult birds must be in good feather condition, waterproof, flighted, and capable of foraging
  • Coordinating the release time with the bird's natural diurnal cycle and migratory schedule enhances post-release survival
• Raptor species

  • American kestrel
  • Screech owl
  • Red-shouldered hawk
  • Barred owl
  • Cooper's hawk
  • Red-tailed hawk
  • Great-horned owl
  • Black vulture
  • Turkey vulture
  • Osprey
  • Bald eagle
• Dally food requirements


  • 20-30g mouse
  • 60-75g mouse, rat, chick
  • 80-90g mouse, chick, quail
  • 110-120g mouse, chick, rat
  • 175-200g rat
  • 200-225g fish
  • 250-300g rat, fish
• Birds of prey


  • Very diverse group
  • Natural habitat varies from open fields and dry desert to dense woods and waterways
  • Obligate carnivores and normal prey varies
  • Many species scavenge carrion for a significant part of diet, but majority hunt live prey
  • Most species do well on a diet of thawed frozen prey
• Majority of birds of prey eat rodents, but osprey (sea hawks) are strictly piscivorous (feeds on fish) and accipiters (sparrowhawk or gohawks) primarily eat other birds
• Bald eagles will eat rodents or fish but also scavenge from carcasses
• Supplementation with vitamins is recommended 2-3 times per week and important when feeding exclusively fish diets since many species of fish contain thiaminas
• Raptors


  • Belong to the Order Accipitriformes, which includes hawks, eagles, vultures, and ospreys
  • Generally fall into four major groups: hawks, falcons, owls, and vultures
  • Characterized by hooked beaks and sharp talons, both of which are used for grasping and tearing flesh
• Identification and aging of birds of prey are both difficult and crucial to proper care while in captivity
• Hawks


  • The family Accipitridae includes the majority of the diurnal raptors worldwide with greater than 230 species, from the Buteo hawks, the accipiters, to the kites and eagles
  • Habitat ranges across the globe
  • Usually monogamous and often pair for life
  • Stick nests are typically built or used, oftentimes lined with leaves or other material to protect the eggs
  • Usually one clutch of eggs is laid each year and both sexes will incubate them, although this is typically the responsibility of the female
  • The incubation period ranges from 28 to 35 days depending on the species and clutch size varies widely, with 2-3 eggs being most typical
  • The young are altricial (born helpless) but eyes open quickly after hatching
  • Young of smaller species can fledge (develop feathers) as early as 3-4 weeks of age
  • Male does most of the hunting, Female stays near the nest
  • Most species display reverse sexual dimorphism (female is typically larger than the male)
  • Plumage coloration is designed to blend into the environment
  • Sexual dimorphism (sexes exhibit different morphological characteristics) is rare
• Falcons


  • Includes the true falcons such as the peregrine falcon as well as the caracaras
  • Typically have long pointed wings and are known for very high speeds in level flight
  • Many falcon species have a dark vertical bar in their plumage beneath each eye
  • Have a small "tomial" tooth on the edge of the upper beak
  • Many have a small protuberance in the center of each nare that assist in airflow when flying at high speed
  • Habitat ranges from northern frozen tundra to arid desert
  • Many falcons, such as the peregrine, catch prey in flight and birds can make up a large portion of the diet
• Owls


  • Include the typical owls in Family Strigidae as well as the barn owls in family Tyonidae
  • Mainly nocturnal, although there are several exceptions (short-eared owl (Asio flammeus) which is diurnal
  • Most owls have forward-facing eyes, facial discs surrounding the eyes, zygodactyl (feet 2 toes pointing forward, 2 backward) and feather adaptions that decrease sound during flight
  • Many owls have horn-like feather tufts functions as camouflage
  • Owls are more to swallow their prey whole
  • Owls do not have a crop (ingluvies) and their pellets, unlike those of diurnal birds of prey, contain undigested bones
• Barn owl (Tyto alba)


  • The most widespread owl
  • Morphologically and behaviorally distinct
  • Long, thin legs, heart-shaped facial discs
  • Breed year-round
  • Habitats - Arctic tundra and rainforests to farmland
  • Diet and desired prey vary widely from small insects, rodents, crayfish, and even fish to large mammals
  • Whereas hawks and their allies are mostly visual hunters, owls rely on sound as well as sight
  • Many owls maintain permanent territories
  • Some do migrate, but not to the distance of diurnal (daytime) raptors
• Vultures


  • The New World vultures of family Cathartidae are similar to Old World vultures but are actually more closely related to storks
  • Large, soaring scavengers, wingspan of up to 9 ft (2.7 m) in the California condor (Gymnogyps californianus)
  • Diet consists mostly of carrion, but black vultures (Coragyps atratus) and turkey vultures (Cathartes aura) have been known to take live prey such as nestlings or newborn calves
  • Large groups will often form around a carcass to feed, with black vultures being the more dominant species
  • Head and neck are bare as adults (help keep clean while feeding carcass)
  • The feet are adapted for walking, weak with short talons
  • Vulture feet are not adapted for carrying food
  • Carry food in their crop and regurgitate at the nest site to feed their chicks
  • Fledging takes much longer than in most other raptors
  • These birds are particularly easy to malimprint (too habituated to humans)