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| Important key words or phrases. | |
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1. Learning Objectives
This section pulls together many of the diseases already discussed and helps to put them in a species-oriented perspective. In addition some specific captive husbandry, management and rehabilitation issues will be introduced. Students should also be familiar with the following new topics:
- Understand the significance of environmental contaminants on wild waterfowl.
- Understand the pathogenesis and significance of botulism in wild waterfowl
- Be familiar with the emerging condition called avian vacuolar myelinopathy
2. Waterfowl
2.1. Waterfowl Taxonomy
| Order Anseriformes - Anatidae | |
| Anatinae - true ducks | |
| Tadornini | shelducks |
| Cairnini | perching ducks [spur-winged geese, muscovy, wood duck] |
| Anatini | dabblers [mallards, etc.] |
| Aythyini | pochards & allies [scaup, etc.] |
| Mergini | eiders, scoters, mergansers, etc. |
| Oxyurini | stiff-tailed ducks |
| Meranettini | torrent ducks |
| Anserinae | |
| Cygnini | swans |
| Anserini | geese |
| Dendrocygnini | whistling ducks |
2.1.1. Taldorini (Shellducks and allies)
- Somewhere between true geese and ducks
- Long necks and legs
- Some are sexually dimorphic
- Old World ducks
2.1.2. Cairnini (perching ducks)
- Muscovy, mandarins, wood ducks etc.
- Surface feeders
- Nest in holes in trees
2.1.3. Anatini (dabblers)
- Mallards, teal, shovelers, pintails and many others
- Dabble in shallow water for food
- Often upend when feeding
2.1.4. Aythyini (pochards and allies)
- Found worldwide
- All freshwater, except scaup
- Bodies are short and rounded
2.1.5. Mergini
- Mergansers, scoters, goldeneye Inhabit fresh and seawater
- Typically hole nesters
- Eat shellfish and crustaceans
- Mergansers have pointed beaks with toothlike projections
2.1.6. Somateriini (eiders)
- Open sea and coastal waters
- Eider down used to line nests
- Males have conspicuous plumage during breeding season
2.1.7. Oxyurini (stiff tailed ducks)
- Ruddy ducks
- Stiff tail used as a rudder
- Large feet, difficulty walking on land
- Nest on floating platforms
2.1.8. Merganettini (torrent ducks)
- Three species
- Western South America
- Fast flowing rivers
- Swims and dives in rapids
- Sexually dimorphic
2.1.9. Cygnini (swans)
- Mute, trumpeter, tundra, whistling swans
- Longlived
- Sexually monomorphic
- Pair for life
2.2. Anatomy
![]() Prolapsed phallus in a duck
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- Sexing: phallus of males
- Sex specific modifications of the syrinx and trachea
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- Geese and swans molt once a year, ducks twice a year
- Post breeding "eclipse" (postnuptial molt)
- Highly modified and sensitive beak for seeking and processing different food sources
- Webbed feet: anisodactyl/palmate, 3 digits forward, one in back (often vestigial)
- Crop variable
- Large cecae
- Grit present inlarge, thick walled ventriculus , especially in granivores
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2.3. Handling and restraint
- Chief defenses are beaks, wings, and feet
- Grasp neck just below head with one hand
- Place other arm around and under body, hold to handlers body
2.4. Captive management
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- For indoor hospitalization,
- Provide a dry, warm enclosure with nonslip flooring
- Keep quiet, dimly lit
- Try to move outdoors if held longer than 48 hours
- Provide access to water and padded flooring
- Feed high quality ground waterfowl pellets, lots of greens, e.g. duckweed
- Domestic waterfowl
- selected for size, growth rate, carcass quality, egg production
- Not easily stressed
- House indoors at night
- Ornamental waterfowl
- commonly pinioned or kept in netted pens
- Need access to stream or pond
- Easily stressed
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Water quality very important: flow
through vs. filtration (dealing with effluent)
- Routine demudding necessary
- Reed beds can act as purifiers
- Seaducks and diving birds require deep water that is ice-free in winter
- Dabblers require an expanse of shallow water s edge
- Construction of ponds and natural vegetation; tendency of
geese to nibble
- Stone or concrete often used, watch for foot problems
- Vegetation should not be too dense, can lead to crop impactions
- Certain parasites overwinter on grass

- Animal density, species compatability
- Breeding
- Escape and predation
- Fencing works for some species
- Traps
- Bait boxes
- Netting for aerial predators
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2.5. General care
2.6. Nutrition
Wide diversity of natural food habits
2.6.1. Commercially prepared diets
- Starter (19-22% protein) for first 2-3 weeks of life
- Grower (12-17% protein) up to 4-6 months of age
- Breeder (17-18% protein) for the period prior to and running throughout laying
- Maintenance (up to 14% protein) for general nonbreeding use
- Game bird, trout, sea duck chow
- Avoid medicated poultry feed!
- Supplement with greens, grit, and oyster shell especially in young birds
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2.6.2. Nutritional diseases
2.6.2.1. Angular limb deformities
- Perosis, Slipped tendon (bandylegs), Angel wing
- Seen in rapidly growing young
- Diet too high in protein, too low in Ca or Vit D
- Poor flooring substrate contributes to development
- Correct by increasing greens, decreasing commercial diet, supplement with Ca and P, correct caging
- Some attempt to correct with bandaging
2.6.2.2. Thiamin deficiency in fish-eaters
- From feeding frozen fish without B1 supplementation
- Defrosting of fish leads to activation of thiaminase
- Clinical signs are neurologic - ataxia, weakness, opisthotonus
- Responds well to treatment with up to 20 mg/kg thiamin IM weekly
2.6.2.3. Vitamin E deficiency
- Young growing ducks fed "old" feed or inappropriate feed
- Diet with rancid fat, requiring more antioxidant activity
- Encephalomalacia, exudative diathesis, reproductive abnormalities
- Muscle degeneration, capture myopathy
- Steatitis in piscivores fed high fat content fish
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2.7. Infectious disease transmission
Exchange of disease between wild and domestic populations through:
- Direct contact
- Environmental contamination
- Vectors
2.8. Viral diseases
2.8.1. Duck plague - duck viral enteritis (DVE)
- Herpesvirus
- Variation in susceptibility and mortality
- Shed through fecal/oral discharge
- Most often seen in nonmigratory waterfowl
- Acute (sudden death), hemorrhagic, massive outbreaks
- MLV vaccine available for domestic ducks
- Differential diagnosis DVH, Erysipelas
- REPORTABLE
2.8.2. Duck viral hepatitis - picornavirus
- Picorna virus
- Primarily in Pekin ducklings - rapid onset of 100% mortality
- Lethargy, CNS signs, death
- Adult mallards as transport hosts
- Muscovy are resistant
- Vaccination of breeding females
2.8.3. Goose viral hepatitis
- Parvovirus
- Not yet known in US
- Ataxia, diarrhea, coryza
- Goslings < 30 days of age
- Diagnosed with virus isolation
- Vaccinate breeding birds
2.8.4. Avian influenza (fowl plague)
- Orthomyxovirus
- Domestic turkeys and ducks at risk
- Migratory waterfowl may be the viral source (fecal-oral)
- Mortality low in waterfowl
- Conflicts between Poultry industry and waterbird habitat projects
2.8.5. Newcastles disease - paramyxovirus 1
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- Double crested cormorants
- Mostly nestlings and subadults affected
- Highly contagious
- Shed in feces
- CNS signs
- REPORTABLE
2.8.6. Poxvirus
![]() Common Murre with pox
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- Avipoxvirus group
- Songbirds, gamebirds, marine birds susceptible
- Mosquitoes are common vectors
- Wartlike nodules on featherless areas of the body
- Emerging disease - reason unclear
2.9. Bacterial diseases
2.9.1. Avian cholera - Pasteurella multocida
- Many taxa of birds affected varying susceptibility - waterfowl and coots
- Environmental contamination with the organism
- Ingestion most common route of infection
- CNS, GI signs, Acute death, hemorrhagic
- Control with early detection, carcass collection and incineration, habitat management
- Concerns raised about biological costs
- Four major geographic foci - CA, OR, TX, NE
- 2004 outbreaks in ruddy ducks in CA and cormorants in South Africa.
2.9.2. Riemerella anatipestifer
- Iinfectious serositis, fibrinous air sacculitis, pericarditis
- Septicemic disease of young domestic ducklings
- Also seen in young swans and geese in the wild
- GI, respiratory, CNS signs
- Differential diagnosis Salmonella, colisepticemia, Newcastle?
2.9.3. Botulism (limberneck)
![]() Botulism in a gadwall
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- Western duck sickness, alakali poisoning
- Paralytic, often fatal
- C. botulinum toxin, type C in waterfowl, Type E in loons and gulls
- One of most important diseases of migratory birds
- Summer/fall incidence
- Carcass-maggot cycle
- Affects peripheral nerves
- Can sometimes recover with supportive treatment
- ELISA test for type C toxin now available for diagnosis from the National Wildlife Health Center http://www.nwhc.usgs.gov/
2.10. Fungal diseases
2.10.1. Aspergillosis - A. fumigatus
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- Opportunistic organism
- Sensitive species: swans, eider ducks, snow geese, seabirds, etc.
- Acquire through inhalation of spores
- Brooder pneumonia in chicks
- Emaciation, dyspnea, voice change, chronic anemia
- Difficult to diagnose in early stages
- Combination antifungal rx
![]() Aspergillus from a Murre
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2.11. Parasitic diseases
2.11.2. Other protozoans
- Coccidia
- Infection of kidneys is common
- Young birds
- Cryptosporidium
- Replicate in GI and respiratory tracts
- Domestic and wild ducks and geese
- Sarcocystis
- Rice grainlike macroscopic cysts in muscle
- Does not cause obvious morbidity or mortality
![]() Coccidian parasites found in waterfowl
feces
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2.11.3. Ectoparasites
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2.11.4. Trematodes
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2.11.6. Nematodes
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2.12. Miscellaneous diseases
2.12.1. Gout
- Articular or visceral
- Uric acid crystals precipitate in the kidneys
- Can lead to postrenal obstruction
- Rapid and severe rise in uric acid levels
- Precipitation on visceral surfaces, joints
- Hyperkalemia leading to cardiac arrest
![]() Visceral gout in a bird
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2.12.2. Capture myopathy
- Caused by improper handling or stress that causes overexertion
- Striated muscle damage
- Warm temps are a risk factor
- Light colored muscles on necropsy exam
2.12.3. Frostbite
- Dry gangrene of extremities
- Tropical and neotropical species are more susceptible
- Can develop secondary septicemia or bacterial endocarditis
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2.12.4. Amyloidosis
- Commonly seen in Anseriformes, gulls and shorebirds
- Deposition of amyloid A in various organs
- Degradation product of acute phase, reactive protein
- Seen with chronic infections
- Can lead to severe hypoalbuminemia
2.12.5. Environmental contaminants
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- Petroleum
- Heavy metals
- Lead, Mercury
- Arsenic, cadmium, selenium
- Pesticides
- Organophosphates, organochlorines etc.
- PCBs, dioxins
- External effects of oil on waterfowl
- Skin, ocular burns
- Feather contamination leading to Lloss of waterproofing, loss of buoyancy and the inability to fly
- Internal effects of oil on waterfowl
- Gastrointestinal
- Respiratory
- Neurologic
- Hematologic
- Reproductive
- Immune system
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2.12.6. Foreign body ingestion and entanglement
- Fishing gear : lead sinkers, jigs, fish hooks, fishing line
- Plastic trash: six pack rings, cigarette lighters, balloons
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3. Raptors
3.1. Raptor Taxonomy Order Falconiformes
| Order Falconiformes | |
| Cathartidae | New World Vultures incl. Condors |
| Accipitridae | Accipiters: Goshawk, Cooper's, Sharp-shinned |
| Buteos: Red-tail, Red-shouldered, Broad-wing | |
| Harriers: Marsh Hawk | |
| Kites | |
| Eagles: Bald eagle, Golden eagle | |
| Old World Vultures | |
| Buzzards | |
| Pandionidae | Osprey |
| Falconidae | Falcons Kestrel, Merlin, Peregrine Caracaras |
- Generally diurnal
- Spend much of time on land
- Carnivorous
- Molt annually (gradual)
- Some sexual dimorphism
- Young are altricial
- Hooked beak and talons
- Crop present
- Generally no grit in thin walled ventriculus
- Small cecum, no distinct phallus
- Anisodactyl- three digits forward, one in back
3.1.1. Family Cathartidae (New World vultures)
Do not have a grasping foot
Small unfeathered head and hooked bill
Weak talons
Regurgitate as a defensive action
Acute sense of smell
3.1.2. Family Accipitridae (Kites, Hawks, Eagles) Accipiters
Goshawks, Coopers and sharp shinned hawks
Woodland birds
Prey on smaller birds
Short rounded wings with long tails
Highly stressed
3.1.3. Family Accipitridae - Buteos
- Red tail, red shouldered, broadwinged hawks
- Soaring hawks with broad tails and rounded wings
- Feed on small mammal species
3.1.4. Family Accipitridae - Harriers
Marsh hawk (aka Northern harrier)
Long pointed wings, fly close to ground with wings upraised
Long legs
Eat small mammals, frogs
Hover over wetlands and open fields
3.1.5. Family Accipitridae - Kites
Mississippi, swallow tailed, black shouldered, others
Eat insects, mice, lizards, frogs
Eat and drink while in flight
Found in open woodlands and swamps, rangelands
3.1.6. Family Accipitridae - Eagles
- Bald, Golden Large birds
- Goldens feed on medium sized mammals, snakes, birds, carrion
- Balds feed on fish, carcasses
- Large broad wings
- Powerful feet, beaks
3.2. Raptor Taxonomy Order Strigiformes
| Order Strigifiormes | |
| Tytonidae | Barn owls |
| Strigidae | Great horned owl, Barred owl, Screech owl, Sawhet owl, Snowy owl |
- Mainly nocturnal
- Spend much of time on land
- Carnivorous
- Molt annually
- Primary feathers have serrated edges
- Slight sexual dimorphism
- Young are altricial
- Hooked beak and claws
- Triangulate sound
- Crop absent
- Semi zygodactyl
3.3. Handling and restraint

- The weapons - talons and beak
- The hood - decrease visual and auditory stress
- Transport
- Sturdy boxes or crates
- Sufficient ventilation, avoid placing so that circulation is impaired
- Keep darkened
- Do not use perch, use tail wraps
- Cover floor with carpeting
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3.4. Noninfectious diseases
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- Competition pressure among young in the nest or adults in groups in captivity can lead to starvation
- Trauma - interaction with man-made objects (hit by vehicles, flying into windows or buildings, electrocution, barbed wire entanglement, leg hold traps), ocular trauma in owls
- Gout
- Predisposing factors include high dietary levels of protein and calcium, hypervitaminosis D, poor renal function, dehydration, stress
- Correct diet, decrease Ca, P, Mg, and Vit D3, ensure adequate levels of Vitamins A and B
- Rickets - from feeding just meat without intact bone, can be reversed with proper diet and Ca/P supplementation if not too advanced
![]() Metabolic bone disease in a young raptor
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3.4.1. Toxicity
3.4.1.1. Lead
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3.4.1.2. Mercury
- Exposure occurs through accumulation of mercury in the food chain, agricultural use, point source industrial and mining discharge into the environment
- Toxic form is methylmercury
- Neurologic signs, emaciation
3.4.1.3. Pesticides
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3.4.1.4. Asian vulture die-off
- Precipitous population decline in the 1990 s in Gyps sp. in India >95% of vultures have died
- Necropsy findings showed birds with severe visceral gout and acute renal failure
- Diclofenac identified as the toxic agent
- Human NSAID recently used in Pakistan for pain relief in domestic livestock
- Vulture feeding on carcasses ingested diclofenac in lethal quantities
- All vultures with visceral gout had diclofenac in their kidneys
- Experimental exposure trials conducted
3.5. Infectious diseases
3.5.1. Viral diseases
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- Poxvirus - especially eagles
- Herpesvirus - Owl herpes, falcon herpes, eagle herpes
- Transmitted through feeding on infected prey
- Carrier status
- Depression, sudden mortality
- Virus isolation, intranuclear IB in liver, spleen, bone marrow
- Adenovirus - from avian derived food
- Melena, anemia
- High mortality in kestrels with hemorrhagic enteritis
- Two types of intranuclear IB
- Paramyxovirus
- Low to moderate susceptibility
- Have seen anorexia, torticollis, and sudden death in owls
- May show long term fecal viral shedding
- Nonpurulent encephalitis
- West Nile Virus - Raptors moderately susceptible
3.5.2. Bacterial diseases
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Bumblefoot/pododermititis
- Falcons especially
- Initial injury, inappropriate perching surfaces
- Plantar surface of metatarsal pad
- Staph aureus, others
- Antibiotics, bandaging, surgery, correct predisposing conditions
- Avian TB - Widespread problem in raptors, GI form predominant
- Chlamydiosis - chronic form seen in raptors
3.5.3. Fungal diseases
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3.5.4. Parasitic diseases
3.5.4.1. Protozoa
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- Plasmodium
- Haemoproteus
- Leukocytozoon
3.5.4.2. Liver/intestinal trematodes
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3.5.4.4. Nematodes
- Ascarids
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Capillaria
- Very common in raptors
- Oropharynx, esophagus, intestinal tract
- Earthworms play a role in transmission
- Can become infected by ingestion of infected prey
-
Syngamus
- Adult worms live in trachea
- Ingestion of transport hosts (earthworms, snails)
- Eggs are coughed up and excreted in feces
- Upper airway obstruction, sneezing, headshaking
- Seratospiculum
- Mites, lice, Hippoboscid flies
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3.6. Avian Vacuolar Myelinopathy "Coot and Eagle Brain Disease"
- First described in bald eagles in 1994. Also seen in American coots and ducks.
- Restricted to the Southeastern US so far.
- Clinical signs of ataxia, wobbly or uncoordinated flight, swimming in circles
- Birds often found dead
- NO gross lesions; histologic examination shows vacuolization and diffuse spongy degeneration of white matter in the central nervous system.
- Etiology unknown. Toxic exposure is suspected.
4. Ancillary Material
4.1. Readings
4.1.1. Texts and Articles
4.1.1.1. Waterfowl references
Altman, Robert B., et al. Avian Medicine and Surgery. Philadelphia. W.B. Saunders Co., 1997. Chapter 55
Bellrose, FC. Ducks, Geese and Swans of North America. Stackpole Press. Harrisburg, PA, 1974.
Best practices for migratory bird care during oil spill response. U.S. Fish and Wildlife Service, November, 2003. link
Beynon, Peter H. Manual of Raptors, Pigeons and Waterfowl. BSAVA, 1996.
Cottam, C. Food habits of North American diving Ducks. USDA Technical Bulletin #643, 1939.
Ducks, Geese and Swans of the World. University of Nebraska Press. Lincoln, NE, 1978.
Feierabend, JS and Russell, AB. Lead poisoning in wild waterfowl. National Wildlife Federation, Washington, DC, 1986.
Fowler, ME (ed). Zoo and Wild Animal Medicine. 3rd ed. WB Saunders Co. Philadelphia, PA, 1993.
Friend, M. Ed. Field Manual of Wildlife Diseases: General Field Procedures and Diseases of Birds. United States Department of the Interior, United States Geological Survey, 1999. Available on the web in pdf format at http://www.nwhc.usgs.gov/pub_metadata/field_manual/field_manual.html
Hyde, DO (ed). Raising wild ducks in captivity. EP Dutton and Company, NY. 1974.
Johnsgard, PA. Waterfowl: their biology and natural history. University of Nebraska Press. Lincoln, NE. 1968.
LaBonde, Jerry. Private collections of waterfowl. Proceedings of the Association of Avian Veterinarians, 1996, pp. 215-223.
Larsen, R. Scott, et al. Clinical features of avian vacuolar myelinopathy in American coots. JAVMA, v.221 (1), 2002: 80-85.
Martin, RM. Wildfowl in Captivity. John Gifford Co., London, 1973.
Ritchie, Branson W., et al. Avian Medicine: Principles and Application. Lake Worth, Fla., c1994: Chapter 46.
Russell, WC, Choules, DL and Gauthier, DA. Detergents and waterfowl. Journal of Zoo Animal Medicine, 12:10-13, 1981.
Wild Waterfowl and its Captive Management, Vols. 1 & 2. American Gabe Breeder's Cooperative Federation. Salft Lake City, Utah, 1974.
Wobeser, GA. Diseases of wild waterfowl. Plenum Press. NY. 1981.
4.1.1.2. Raptor references
Altman, Robert B., et al. Avian Medicine and Surgery. Philadelphia. W.B. Saunders Co., 1997. Chapter 52
Beynon, Peter H. Manual of Raptors, Pigeons and Waterfowl. BSAVA, 1996.
Heidenreich, Manfred. Birds of prey. Blackwell Science, 1997.
Redig, P.T. et al. 1994. Raptor biomedicine. Univ. of Minnesota Press, c1993.
4.2. Websites
National Wildlife Health Center 6006 Schroeder Rd., Madison, WI 53711. (608) 271-4640.




















































