TECHNIQUE

Feeding of Casualty Birds of Prey (Wildlife Casualty Management)

Summary Information
Type of technique Health & Management / UK Wildlife Casualty Management / Techniques:
Synonyms and Keywords N.B. This information should be read in association with Wildlife Casualty & Convalescent Feeding which contains background information together with links to the Electronic Library and Organisations (UK Contacts). The related Species pages contain similar linkages.
Description This page has been prepared for the "UK Wildlife: First Aid and Care" Wildpro module, and is designed for the needs of the following species: Accipiter gentilis - Northern goshawk, Accipiter nisus - Eurasian sparrowhawk, Aquila chrysaetos - Golden eagle, Buteo buteo - Common buzzard, Buteo lagopus - Rough-legged buzzard, Circus aeruginosus - Western marsh harrier, Circus cyaneus - Northern harrier, Circus pygargus - Montagu's harrier, Haliaeetus albicilla - White-tailed eagle, Milvus milvus - Red kite, Pernis apivorus - European honey buzzard, Pandion haliaetus - Osprey, Falco columbarius - Merlin, Falco peregrinus - Peregrine falcon, Falco subbuteo - Hobby, Falco tinnunculus - Common kestrel, Athene noctua - Little owl, Strix aluco - Tawny owl, Asio otus - Long-eared owl, Asio flammeus - Short-eared owl, Nyctea scandiaca - Snowy owl, Tyto alba - Barn owl.

These species are from the families Accipitridae, Falconidae, Strigidae, Tytonidae.

Fluids (water):

  • Offer a rehydration (electrolyte) solution such as Lectade (Pfizer Limited) to drink on admission.
  • Water should be freely available at all times unless the casualty is unconscious or severely debilitated and unable to hold its head up.
  • Both water and a rehydration (electrolyte) solution, in separate containers, should be made available initially.
  • (V.w5, V.w26)
  • Gavage with rehydration (electrolyte) solution may be required on admission.(B156.15.w15, D24)
  • Birds of prey often do not drink. Food may be moistened with water or rehydration solution, or placed in a water bowl, to increase fluid intake. (B118.16.w16)

Convalescent Diet:

  • Casualties are often anorexic when presented and have an immediate requirement for energy. (B156.15.w15)
  • Hills A/D (Hill’s Pet Nutrition Ltd.); this may be mixed with rehydration solution (50:50 mixture of A/D (Hill’s Pet Nutrition Ltd.,) and rehydration (electrolyte) solution). (V.w5, V.w26)
  • Formula designed by The Raptor Center, University of Minnesota: Prepare 30 % solution of Nutrical (Evsco Pharmaceutical) in electrolyte (rehydration) solution (30ml Nutrical plus 70ml electrolyte (rehydration) solution) and store in refrigerator. Mix with human infant "second food" series meat paste (beef, veal, chicken or turkey) in a ratio of one part solution to two parts baby food ( 30ml of 30% Nutrical solution plus one 60g jar of baby food). Tube feed 40ml/kg three times daily.(B11.4.w17)
  • Proprietary products such as Critical Care Formula (Vetark Animal Health) have been specifically designed as a short term product for anorectic and sick birds. (V.w26)
  • Use of convalescent diets:
  • May be given by crop tube (gavage feeding).
  • Give up to 2% of body weight per feed.
  • Assume 1ml of made-up feed equals 1g, therefore maximum 2ml of feed per 100g of bird.
  • (B156.15.w15)
  • See: Gavage / Tubing of Birds
  • Feeding meat without roughage may be useful short-term to build up condition: since it is not necessary to wait for the casting to be produced before the next feed, several feeds per day may be given (always wait until the crop has emptied before feeding the next meal). (B156.16.w16)

Technique for assisted (force) feeding: 

  • May be required for anorectic birds, and for birds with bill or feet injuries which interfere with food handling. 
  • Chopped up boluses of food should be used, of a size appropriate for easy swallowing for the bird.
  • The bird is held (may be wrapped in a towel with the head visible).
  • Tapping the side of the bill gently may encourage the bird to open its mouth; otherwise gently open the bill.
  • Use tweezers to introduce small pieces of meat into the mouth.
  • Allow the bird to control whether or not it swallows.
  • Do not feed a large quantity of meat at one time.
    • For diurnal raptors, monitor the degree of crop distention during feeding.
    • Do not feed again until the crop has emptied from the previous meal.
    • Convalescence diets given by gavage are required for very weak birds (see above).
  • There is an increased risk of regurgitation if large quantities of food are given at any one time when assisted feeding is used. 
  • Species and individuals vary greatly in their acceptance of assisted feeding. It may not be accepted by flighty individuals and species such as  Accipiter nisus - Eurasian sparrowhawk.
  • (D24)

Short term Maintenance Diet:

Food Presentation:

  • Offer food twice daily, replacing uneaten food.
  • Offer on the floor or in a shallow dish.
  • Offer various presentations initially, e.g. whole day-old chick, day-old chick split so the viscera are exposed, chopped day-old chick in rehydration (electrolyte) solution such as Lectade (Pfizer Ltd.).(D24)

Suggested short term maintenance diets include: 

  • Whole rodents, whole birds or whole fish, depending on raptor species. (B16.20.w20)
  • Dead day-old chicks, quail, rats, mice, guinea pig, rabbit and beef or horse meat; avoid feeding only a single food type for long periods.(D18)
  • Mice, rats, day-old chicks.(P24.233.w9)
  • Provide the natural food for the species if possible.(B118.16.w16)
  • Provide a variety of food items, particularly if the food provided is dissimilar from natural prey, to reduce the risk of the bird learning to concentrate on a single food type, especially one which is unnatural.(J23.23.w2)
  • Food which looks like the natural prey may be eaten more readily that that which does not, for example brown laboratory mice may be taken more readily than white laboratory mice.(J23.23.w1)
  • Fresh road-killed birds may be useful.(B118.16.w16,  B156.16.w16)
  • Young mice and rats are useful for owls and kestrels. (B118.16.w16)
  • Day-old chicks are useful; a vitamin/mineral supplement must be added if they are used for more than a few days.(B118.16.w16, B156.16.w16)
  • Quail, young chicken poults and young turkey poults may be used. (B156.16.w16 )
  • Fresh raw meat such as shin beef may be used. This should be supplemented with vitamin/mineral supplement, sterilised bonemeal for added calcium and roughage in the form of e.g. dog or cat hair, rabbit fur or small chicken or passerine feathers to allow the formation of a pellet (casting) for regurgitation. (B118.16.w16, B156.16.w16, D24)
  • Mice or rabbit may be used to tempt inappetant birds.(D24)
  • For Pandion haliaetus - Osprey fish should be provided, e.g. herring plus fresh water fish as available.(J23.23.w1)
  • Barn owl may only eat rodents.(B203)
  • Barn owl: dead day-old chicks, with occasional small mammals such as domestic mice or "weaner" size rats.(D47)
    • Supplement day-old chicks with small amounts of vitamin-mineral supplement such as SA37 (Intervet UK Ltd.) or Vionate (E.R. Squibb and Sons Limited) if only chicks are used.(D47)
    • Small mammals (mice, voles, shrews, moles, nestling rabbits) and small birds killed and brought home by cats may be used, but not if rodent poisons have been used nearby.(D47)
  • Guidance for amounts:
  • If all the food is eaten, offer more; if food is left, decrease the amount offered.
  • Kestrel: one day-old chick per day. (B156.16.w16)
  • Female goshawk: 4-5 day-old chicks per day.(B156.16.w16)
  • Tawny owl: two or three day-old chicks daily, plus a mouse twice weekly. (B203)
  • Barn owl: 1.5 to 2.5 day-old chicks per night.

In an emergency:

  • Any fresh raw meat such as mince, heart, shin beef, chicken etc.(B156.16.w16, B203, D47)
Appropriate Use (?)
  • Fresh drinking water should always be available in a container of an appropriate size and type for the species concerned.
  • Fluid replacement therapy other than oral fluids may be required for casualties which are extremely dehydrated on admission or are unable to take in and absorb oral fluids.
    • Fluid therapy should continue until the animal is no longer dehydrated, even if it is self feeding.
  • Feeding of convalescents should take into account their requirement for additional nutrients for healing as well as maintenance requirements.
  • Water is rarely drunk by birds of prey, but should be offered as routine and should also be provided for bathing. (B118.16.w16, V.w26)

Notes
  • The required fluid intake for maintenance should be considered when designing convalescent diets.
  • Energy requirements for maintenance and healing should be calculated and used to determine the quantity of food required for both convalescence and short-term maintenance diets.
  • Convalescent diets should be easily absorbed/digested.
  • Care should be taken not to under or over supplement with vitamins/minerals.
  • Diets intended for feeding from a syringe or by stomach tube (gavage) must be of a sufficiently fluid consistency to pass through the syringe nozzle or down the tube without it becoming blocked.
  • The natural diet should be considered when deciding on suitable ingredients, including consideration of taste/smell.
  • Fresh food must be provided daily.
  • Regular cleaning of food and drinking water containers (e.g. daily) is important to reduce the risk of disease.
  • Food and water containers should be sited to minimise the risk of contamination with droppings/faeces/urine. 
Complications/ Limitations / Risk
  • Species and individuals vary greatly in their acceptance of assisted feeding. It may not be accepted by flighty individuals and species such as  Accipiter nisus - Eurasian sparrowhawk.
  • Large meals fed to weak birds may not be digested but sit in the crop and putrify (sour crop), necessitating removal of the rotten food.
  • There is an increased risk of regurgitation if large quantities of food are given at any one time when assisted feeding is used.
  • There is a risk of the presence of lead shot in wild rabbits and birds and of avian tuberculosis in wild birds. (B156.16.w16, B118.16.w16)
  • Pigeons should be used with caution as they carry Trichomonas gallinae, which may infect birds of prey (See: Trichomoniasis (Flagellate Infection) in Birds (with special reference to Waterfowl)). If pigeons are used, removal of the head and crop first will reduce the risk of the disease; preferably the pigeons should be deep frozen before use. (B118.16.w16)
  • Day-old chicks have a poor calcium:phosphorus ratio and an appropriate high calcium supplement must be added if they are fed for more than a few days.
  • Avoid feeding only a single food type for long periods.(D18)
  • Water bowls should not be left in the accommodation of a casualty which is unconscious or is severely debilitated and unable to hold its head up.
  • Dehydrated and malnourished individuals sometimes drink rehydration fluids but refuse plain water initially; others will drink water but not rehydration fluids. Both should be made available.
  • No diet, however well balanced nutritionally, is useful if the animal does not eat it, for example because it is not recognised as food.
  • Ingestion of food should be monitored, not assumed. This may include weighing food before presentation and weighing waste food after removal, and periodic weighing of the animal.
  • Monitoring of weight/body condition is particularly important for group housed/group fed animals, within which some individuals may take more food and others not get the food they require.
  • Diets suggested on this page are intended for short term use for wildlife casualties; they are not necessarily suitable for long-term use or in individuals which are breeding.
  • Diets suggested on this page are not necessarily suitable for feeding chicks; information on appropriate diets for very young individuals are described in the page on hand-rearing.
  • If naturally-available food items are gathered for feeding to casualties it is important to be aware of the possibility of contamination with chemicals such as herbicides and pesticides.
Equipment / Chemicals required and Suppliers
  • Oral rehydration (electrolyte) solutions are widely available from veterinary suppliers and chemists. 
  • A basic oral rehydration (electrolyte) solution may be made by dissolving one tablespoon of sugar and one teaspoon of salt in one litre of water. (B203).
  • Lectade, Pfizer Limited: from veterinary suppliers and agricultural feed suppliers.
  • Critical Care Formula (Vetark Animal Health, PO Box 60, Winchester, SO23 9XN)
  • A/D Hills Science Diet (Hill’s Pet Nutrition Ltd.) from veterinary suppliers
  • Frozen dead day-old chicks, mice (brown as well as white), rats, quail and rabbits are available from some pet stores (e.g. those with an interest in reptiles) and from specialist suppliers. Pet shops may be able to supply smaller quantities that can be bought from specialist animal feed companies, but the price per item may be higher.
  • Whole fish may be bought from fish markets, bait stores and specialist animal feed suppliers.
Expertise level / Ease of Use
  • Experience is required for assisted feeding of birds of prey.
Cost/ Availability
  • Cost may be considerable if birds of prey are to be fed for more than a few days.
Legal and Ethical Considerations
  • Under the Protection of Animals Acts 1911-2000 it is an offence not to provide animals (including captive wild animals) with necessary food and water.(J35.147.w1, B156.21.w21, B223, P19.2.w1)
  • Care should be taken not to let an individual become accustomed to a single food item as this may result in difficulties in feeding the animal if the food item becomes unavailable, and in preparing it for release.
  • Every effort should be made to provide appropriate natural, locally available foods to animals which have been maintained in captivity for prolonged periods before they are released, in order to re-accustom them to a natural diet and reduce the chance of digestive problems following release.(P24.233.w11)
  • The release of animals which, by virtue of an inadequate or inappropriate diet whilst in captivity, are not fit to survive when released may be considered an offence under the Abandonment of Animals Act, 1960.
Author Debra Bourne
Referee Becki Lawson and Suzanne Boardman
References

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