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Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease description:

Starvation in Waterfowl and Seabirds (with notes on Hedgehogs and Bears) 

INFORMATION AVAILABLE

GENERAL INFORMATION

CLINICAL CHARACTERISTICS & PATHOLOGY

INVESTIGATION & DIAGNOSIS

TREATMENT & CONTROL

SUSCEPTIBILITY & TRANSMISSION

ENVIRONMENT & GEOGRAPHY

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General and References

Disease Summary
Severe weight loss and death associated with lack of food availability, inability to ingest food, or unwillingness to ingest available food.

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Alternative Names (Synonyms)

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Disease Type
Miscellaneous / Metabolic / Multifactorial

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Infectious/Non-Infectious Agent associated with the Disease
Lack of available food. Unfamiliar food.

Infective "Taxa"
  • --

Non-infective agents

 --

Physical agents

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References

Disease Author

 Debra Bourne MA VetMB PhD MRCVS (V.w5)
Click image for main Reference Section

Major References / Reviews

Code and Title List

 B9.6.w1, B10.26.w1, B15, B197.15.w15
J5.18.w4
J7.15.w2, J7.15.w3, J7.15.w5, J7.15.w7, J7.40.w2, J7.50.w1
J30.49.w1
J40.17.w1, J40.48.w1
J50.95.w1

Other References

Code and Title List

 J1.28.w2
J7.15.w1, J7.15.w4
B48.20.w20
P4.1992.w1

Hedgehogs:
B151, B259.w9, B284.2.w2, B337.3.w3, V.w56

Bears
B144, B406.35.w35, 
D245, D252.w27, D248.w9,
P5.29.w5, P85.1.w4

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Clinical Characteristics and Pathology

Detailed Clinical and Pathological Characteristics
General Loss of body fat, emaciation, death.

Clinical Characteristics
  • Loss of body fat and body weight, loss of muscle mass and emaciation, weakness, death.
WATERFOWL
  • Severe loss of weight and condition, emaciation - 35-58% weight loss reported, weakness, death (J5.18.w4, J7.40.w2, B15).
  • N.B. starvation predisposes to various diseases (B9.6.w1).
SEABIRDS 
  • Emaciation.
HEDGEHOGS
  • The skin at the hind end may look "too big" for the hedgehog and may be in folds following rapid weight loss. (B337.3.w3)
BEARS
  • Very poor body condition. (J17.119.w1)
  • Emaciation. (J1.41.w4)

Incubation

 Time to starvation varies depending on the animal's size and initial energy reserves. Small animals generally starve faster than larger animals. Birds generally starve faster than mammals of a similar size, due to higher metabolic rate.
WATERFOWL
  • Deaths from starvation are usually reported at least nine and usually 14 to 21 days after the onset of severe weather restricting food supplies (J7.15.w1)
BEARS
  • In northeastern Minnesota, where food is unavailable for about seven months and bears hibernate for five to seven months, it was noted that while no Ursus americanus - American black bears died of starvation while hibernating, some died in spring after emerging from the den. (D248.w6)

Mortality / Morbidity
  •  
WATERFOWL Not usually high in waterfowl as a percentage of the population (B15).
BEARS --

Pathology

 --
WATERFOWL Absence of subcutaneous and body fat, muscle atrophy, liver and gastro-intestinal tract atrophy, gall bladder dilatation; may be slight atrophy of heart, spleen and kidneys. Total fat may be reduced to less than 1% of total body mass (J7.15.w5, J7.40.w2, J40.17.w1, B15).
BEARS

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Human Health Considerations
--

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Susceptibility / Transmission

General information on Susceptibility / Transmission
Animals are susceptible to starvation if food is unavailable or contains insufficient nutrients. This may occur associated with:
  • Seasonally or associated with adverse weather conditions (e.g. foods under snow in winter, lack of vegetation during drought).
  • Due to failure of normal food sources (e.g. failure of the mast/fruiting season, crash in prey population due to disease).
  • Inability of a predator to hunt due to illness, injury or inexperience.
  • Inability to obtain food due to becoming trapped.
  • Oral, oesophageal, gastric or intestinal obstruction.
  • For neonatal mammals and altricial chicks, if the mother does not care for and suckle the neonate (mammals) or does not provide food (mammals and birds).
  • For animals under human care, if food is not provided, or is insufficient for the animal's needs.
  • Note: 
    • More food is required in cold weather or other situations in which metabolic demands are increased.
    • Hibernating species may die during or soon after hibernation if they did not build up sufficient reserves prior to hibernation.
    • Individuals with a large parasite burden may be more susceptible to starvation.
    • Neonates and juveniles are generally more susceptible than adults.

(B36.51.w51, P24.204.w2, J1.23.w8, J57.8.w1, V.w5)
BIRDS

 
  • Chicks, particularly altricial chicks, are susceptible to starvation if one or both parents, on whom they rely for food, are killed or otherwise unable to provide food.
  • Birds which hunt their food, including raptors and piscivorous (fish-eating) birds, are susceptible to starvation if they do not learn to hunt and catch their prey effectively. They are more susceptible if food supplies are low during the initial period when they are learning to forage properly.
  • Adult and immature birds are susceptible to starvation following Oiling.
    • Oiled birds with disrupted feather structure (see: Oiling) may be unable to forage effectively. They therefore have reduced food intake and at the same time have a greatly increased loss of heat to the environment in cold ambient temperatures than do birds with intact plumage. Therefore they rely on stored energy to maintain body temperature, and may show "greatly accelerated starvation." (J40.31.w2)
    • It is possible that the metabolic rate may also be increased temporarily following ingestion of small amounts of oil, for example while trying to preen fouled plumage, or by consuming contaminated food). In an experiment using double-labelled water in adult Oceanodroma leucorhoa - Leach's storm petrels, birds dosed by intubation with 0.1 mL of Prudhoe Bay crude oil showed significantly higher (P<0.001) higher standard metabolic rate than did control birds which were not given oil. (J55.88.w1)
    • A study of Cerorhinca monocerata - Rhinoceros auklets (Laridae - Skuas, Terns, Gulls, Puffins, Auks (Family)) in the Southern Japan Sea found that dead oiled birds had lost one third of body, muscle and general organ masses, 60% of liver mass, more than 90% of subcutaneous fat and more than half of all fats stored in muscles and other organs, including bone marrow, which was almost entirely replaced with water. It was considered that these birds died not from the oiling per se but from "emaciation caused by starvation and nutritional exhaustion, accelerated by increased energy loss." (J313.40.w3)
      • Oiled birds may suffer energy exhaustion within one or two days of becoming oiled. (J313.40.w3)

WATERFOWL

  • Different studies have variously suggested greater susceptibility to starvation in males or in females (J7.15.w3, B15).
  • Species with more restricted food preferences, and/or preferences for foods more likely to be affected by inclement weather, may be more susceptible to starvation (J7.15.w2).
  • Cold weather increases susceptibility to starvation (B9.6.w1, B15).
  • Also associated with Oiling as oiled birds have lost buoyancy and insulation, may be reluctant to enter the water to feed and require more food for maintenance of body temperature (B15).
SEABIRDS
  • Immature birds which are not yet proficient hunters. (B197.15.w15)
  • Parasitism may increase susceptibility particularly of immature birds. (B197.15.w15)
  • Population pressure may increase susceptibility particularly of immature birds. (B197.15.w15)
  • Inclement weather may reduce opportunities of birds to feed. (B197.15.w15)
  • Failure of local fish stocks. (B197.15.w15)
  • Long migration. (B197.15.w15)
  • Oiling. (B197.15.w15)
HEDGEHOGS
  • Starvation may occur after a hedgehog falls into a steep-sided pit from which it cannot get out (e.g. under a cattle grid, empty outdoor swimming pools etc.) or gets trapped in a shed, or similar. (B259.w9, B337.3.w3)
  • Weight loss due to lack of food may occur also in drought conditions. (B284.2.w2); individuals may be presented thin and dehydrated in hot dry weather. (V.w56)
BEARS
  • In captivity, cubs may die of starvation if abandoned by their mother. (P85.1.w4)
  • In the wild, Ursus americanus - American black bear may cubs die from starvation if their mother is not in good enough body condition to provide them with adequate milk. (B406.35.w35, D245)
  • Young bears may starve to death if food sources disappear due to adverse weather conditions. (B144)
  • In Minnesota, some yearling Ursus americanus - American black bear starved to death after bears emerged from hibernation. (D245)
  • In northeastern Minnesota, where food is unavailable for about seven months and bears hibernate for five to seven months, it was noted that while no Ursus americanus - American black bears died of starvation while hibernating, some died in spring after emerging from the den; those dying generally are those of low body weight for their age. (D248.w6)
    • Of 15 yearlings weighing less than 10 kg at the end of their first hibernation, all died within the next four months, as did two of 13 weighing 10-13 kg, but none of 15 which were heavier than this. A two-year-old female also died of starvation (bone marrow non-fatty) in late spring/early summer having weighed 12.7 in spring as a yearling and only 17 kg in spring when two years old. (D248.w9)
  • In Ursus arctos - Brown bear, mortality in cubs of the year often occurs during denning or in the first month after emergence, probably due to malnutrition. (B406.36.w36)
  • Starvation is recognised as a cause of mortality in wild Ursus arctos - Brown bear. (D243)
  • Helarctos malayanus - Sun bear may die from starvation when the mast (fruiting season) fails. (J17.119.w1, Th9.IV.w4)
  • Young bears are more susceptible than adults; in Ursus arctos - Brown bear in Sweden, in a study of 89 deaths, the three bears which died due to starvation were all under one year old. (J1.41.w4)
  • Ursus americanus - American black bears cubs presenting for rehabilitation in autumn are often starving. (D252.w27)

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Disease has been reported in either the wild or in captivity in:
[N.B. Miscellaneous / Traumatic Diseases tend to be under-reported and the majority are likely to affect all waterfowl species, given exposure to the related disease agents/factors.]
  • Canada geese Branta canadensis, lesser snow geese Anser caerulescens caerulescens, mallard Anas platyrhynchos, King eiders Somateria spectabilis, eiders, white-fronted geese Anser albifrons, American black ducks Anas rubripes, tufted ducks Aythya fuligula (B15).
  • Common shelduck Tadorna tadorna, Brent geese Branta bernicla, Eurasian wigeon Anas penelope (J7.15.w2).
  • European wigeon Anas penelope and Common shelducks Tadorna tadorna, possibly other species including mallard Anas platyrhynchos (J7.15.w3).
  • Mute swans Cygnus olor (J7.15.w4).
  • White-fronted geese Anser albifrons (J7.15.w5).
  • Tufted ducks Aythya fuligula, common pochard Aythya ferina (J7.40.w2)
  • Downy (possibly abandoned) and immature (in winter) mute swans Cygnus olor in Scotland, UK (J7.50.w1).
  • Mallard Anas platyrhynchos (J1.28.w2)
  • Canada geese Branta canadensis (J5.18.w4).
  • Female blue goose (lesser snow goose) Chen (Anser) caerulescens, during incubation, Northwest Territories, Canada (J30.49.w1).
  • Mallard Anas platyrhynchos, experimental (J40.17.w1).
  • Black ducks Anas rubripes, brant geese Branta bernicla (J40.48.w1).
  • Female lesser snow goose Anser caerulescens (Chen caerulescens caerulescens) during incubation, Northwest Territories, Canada (J50.95.w1).
  • Mute swans Cygnus olor in severely cold winter in the UK (B9.6.w1).
  • Ursus maritimus - Polar bear cubs in a zoo, abandoned by their mother. (P85.1.w4)
  • In Ursus arctos - Brown bear, mortality in cubs of the year often occurs during denning or in the first month after emergence, probably due to malnutrition. (B406.36.w36)
  • Ursus arctos - Brown bear in Sweden; three of 98 deaths were due to starvation. (J1.41.w4)
  • Starvation is recognised as a cause of mortality in wild Ursus arctos - Brown bear. (D243)
  • Helarctos malayanus - Sun bear may die from starvation when the mast (fruiting season) fails. (J17.119.w1, Th9.IV.w4)
  • In Minnesota, some yearling Ursus americanus - American black bear starved to death after bears emerged from hibernation. (D245)
  • Wild Ursus americanus - American black bear may cubs die from starvation if their mother is not in good enough body condition to provide them with adequate milk. (B406.35.w35, D245)
  • Starvation was considered the main cause of death in one six-day-old Ursus arctos - Brown bear at Rostock Zoo, in which necropsy revealed an empty stomach. (P5.29.w5)
  • When Ursus americanus - American black bear families were closely monitored after cubs had been fostered into litters, in one litter which consisted of four cubs after adoption, all four cubs died the following spring after emergence from hibernation. (J59.14.w1)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

 BIRDS MAMMALS

(List does not contain all other species groups affected by this disease)

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Disease has been specifically reported in Free-ranging populations of:
  • Canada geese Branta canadensis, lesser snow geese Anser caerulescens caerulescens, mallard Anas platyrhynchos, King eiders Somateria spectabilis, eiders, white-fronted geese Anser albifrons, American black ducks Anas rubripes, tufted ducks Aythya fuligula (B15).
  • Common shelduck Tadorna tadorna, Brent geese Branta bernicla, Eurasian wigeon Anas penelope (J7.15.w2).
  • European wigeon Anas penelope and Common shelducks Tadorna tadorna tadorna , possibly other species including mallard Anas platyrhynchos (J7.15.w3).
  • Mute swans Cygnus olor (J7.15.w4).
  • White-fronted geese Anser albifrons (J7.15.w5).
  • Tufted ducks Aythya fuligula, common pochard Aythya ferina (J7.40.w2).
  • Downy (possibly abandoned) and immature (in winter) mute swans Cygnus olor in Scotland, UK (J7.50.w1).
  • Mallard Anas platyrhynchos (J1.28.w2)
  • Female blue goose (lesser snow goose) Chen (Anser) caerulescens, during incubation, Northwest Territories, Canada (J30.49.w1).
  • Brant (brent) geese Branta bernicla (J40.48.w1).
  • Female lesser snow goose Anser caerulescens (Chen caerulescens caerulescens) during incubation, Northwest Territories, Canada (J50.95.w1).
  • When Ursus americanus - American black bear families were closely monitored after cubs had been fostered into litters, in one litter which consisted of four cubs after adoption, all four cubs died the following spring after emergence from hibernation. (J59.14.w1)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

 Bears (Ursidae - Bears (Family))

(List does not contain all other species groups affected by this disease)

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Environment/Geography

General Information on Environmental Factors/Events and Seasonality
  • Starvation is most common in the winter; food supplies for most birds are lowest from January to June (Northern hemisphere temperate zone). (B203)
  • Starvation is more likely in severe winters. (J1.23.w8)
  • In wild birds, starvation is primarily seen associated with prolonged severe winter weather. Foods may be made unavailable by freezing (e.g. mud flats), or by being covered by frozen snow (e.g. grass). Weather preventing birds moving to other areas in search of food may increase starvation risk. Weight loss is faster in colder weather and a combination of starvation and hypothermia may kill waterfowl before fat reserves are totally exhausted (J7.5.w1, J7.15.w3, J7.15.w5, J7.40.w2, B15).
  • Starvation also occurs in summer in some incubating birds with insufficient fat reserves (J30.49.w1, J50.95.w1, B15).
  • May be associated with period of migration (B197.15.w15)
  • Birds may starve following Oiling, since they are unable to fly, swim etc. and find food. (B36.42.w42)
HEDGEHOGS
  • May be seen associated with drought conditions when invertebrates are scarce. (B284.2.w2, V.w56)
BEARS
  • Young bears may starve to death if food sources disappear due to adverse weather conditions. (B144)
  • Helarctos malayanus - Sun bear may die from starvation when the mast (fruiting season) fails. (J17.119.w1, Th9.IV.w4)
  • Bears may survive hibernation but starve in the following weeks after emergence in the spring. (J59.14.w1)

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Regions / Countries where the Infectious Agent or Disease has been recorded
  • In waterfowl: USA, Canada, UK, Switzerland. (J7.40.w2, B15)
  • In bears: North America, Asia, (B406.35.w35, D245, D248.w6, J17.119.w1, Th9.IV.w4)

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Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

  • In waterfowl: USA, Canada, UK, Switzerland (J7.40.w2, B15)
  • In bears: North America, Asia, (B406.35.w35, D245, D248.w6, J17.119.w1, Th9.IV.w4)

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General Investigation / Diagnosis

General Information on Investigation / Diagnosis
  • Emaciation, lack of lesions suggesting other causes of emaciation and death.
WATERFOWL Emaciation, lack of lesions suggesting other causes of emaciation and death. Measurement of medullary fat content in ulna: normal level may be 30%, remains until total body lipid reduced below 5%, then falls rapidly (J40.48.w1, B15).
BEARS
  • Emaciation, low body weight (D248.w9, J1.41.w4)
  • Bone marrow non-fatty. (D248.w9)
Related Techniques
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Similar Diseases (Differential Diagnosis)
Weight loss and emaciation may be seen in association with various infectious or non-infectious diseases. (B284.2.w2)
WATERFOWL 
  • Emaciation is part of the terminal stage of many diseases. Other likely explanations of emaciation (other diseases) must be eliminated before starvation is diagnosed as the cause of death (B15). (See also: Caloric Exhaustion.)
  • Starveout is a form of starvation peculiar to neonates, which sometimes fail to learn to feed adequately (B10.26.w1).
  • Echinuriasis (Acuariasis) may cause inappetance and blockage of the proventriculus in waterfowl, leading to death through starvation (B48.20.w20).
HEDGEHOGS
BEARS
  • --

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Treatment and Control

Specific Medical Treatment
--
BEARS
  • --
Related Techniques

 
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General Nursing and Surgical Techniques
--
WATERFOWL
  • Providing a warm environment and plentiful food allows rapid recovery of body mass. Lost weight may be recovered in as little as two to three weeks (J7.15.w4, J40.17.w1).
  • Force-feeding may be required initially in very weak birds or birds failing to eat despite available food (J5.18.w4).
SEABIRDS
  • Careful nursing required for emaciated birds which have been starving for some time. (B197.15.w15)
  • High-energy diet may be given by gavage:
  • Convalescent diet, to be given at 10% body weight per day, by gavage, split into two to four feeds:
  • Avoid overfeeding as this may lead to collapse and death, apparently as a result of circulatory failure precipitated by the physiological demands of a full proventriculus. (B197.15.w15)
HEDGEHOGS
  • An easily digested diet should be offered initially. Provide small amounts of tempting foods repeatedly. (B151, V.w5)
  • Hand feeding with a convalescent diet may be required if starvation has occurred associated with mouth injury. (B337.3.w3, V.w5)
  • Administer vitamins (particularly B-vitamins and D-vitamins) and calcium supplementation to weak and underweight hedgehogs at the time of admission. (B291.12.w12)
BEARS --
Related Techniques
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Preventative Measures
Vaccination --
BEARS --
Prophylactic Treatment

Ensure appropriate food is available and accessible, particularly when animals are hospitalised and may have reduced mobility. (V.w5)

WATERFOWL

 Ensure food availability, increase energy in diet in cold weather. Food should be provided ad lib after a week of severe weather and extra feeding continued for three weeks after the end of a cold spell. Providing warm drinking water may increase feed intake (J7.15.w7, P4.1992.w1).
BEARS Ensure appropriate food is available and accessible, particularly when animals are hospitalised and may have reduced mobility. (V.w5)
Related Techniques
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Environmental and Population Control Measures
General Environment Changes, Cleaning and Disinfection --

WATERFOWL
  • Providing shelter such as windproof screens, by decreasing heat loss may decrease use of energy reserves and thus risk of starvation (J7.15.w7).
  • Prohibition of wildfowl hunting during most severe weather, particularly when inter-tidal flats are frozen (J7.15.w3).
BEARS
  • --
Population Control Measures --
BEARS --
Isolation, Quarantine and Screening --
BEARS --
Related Techniques
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