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Introduction and General Information

After oiled animals have been washed, rinsed and dried, a further period of rehabilitation is required before they are released. The purpose of this part of the rehabilitation process is to prepare the animals for release and to give them the best possible chance of surviving after release. (B188, P62.2.w1)

Note: Final assessment of the suitability of individual casualties for release is considered in Release of Oiled Wildlife - Assessment for Release

It is important to remember that release is a stressful time for the bird, which must therefore be as fit as possible prior to release.

During the rehabilitation period the individual must:

  • Regain full waterproof status and feather structure;
  • Reach an appropriate weight and body condition;
  • Regain fitness;
  • Achieve a normal or near-normal physiological status, particularly regarding PCV (i.e. it must not be anaemic);
  • Return to normal behaviour;
  • Be examined and assessed as being ready for release.

(B363.11.w11, P24.335.w21)

This rehabilitation period may last days to weeks depending on the condition of the casualties. (B363.Intro.w21). On average, birds will remain in care after cleaning for about three to 14 days. (D159.III.w3)

  • Birds which have been in care for a short period (one to two weeks) may require little preparation for release after regaining waterproofing, while birds which have been in care for longer, or were oiled and debilitated for some time before being taken into care, may require longer to exercise and regain fitness. (B363.11.w11)
  • The longer a bird is maintained in captivity the more likely it is to develop captivity-related secondary problems such as keel lesions, bumblefoot, feather damage and bacterial or fungal diseases (e.g. aspergillosis). Birds should be released as soon as they are fit and ready. (D135.7.w7, J313.1.w1)
  • There is a risk of individuals becoming tame and therefore unsuitable for release if kept in captivity for long periods. (D214.2.w2)

Stress reduction

Stress reduction is a vital part of successful rehabilitation. (B23.38.w2, J311.9.w1)

  • Stress may be reduced by minimising disturbance in the form of unnatural sights, sounds and smells and by making an effort to provide surroundings which simulate the birds' normal environment in terms of appropriate housing, social groupings, ventilation and diet. (B23.38.w2)
  • NOTE: for birds which are easily stressed, housing may need to be provided in a restricted area with an absolute minimum of disturbance. (D135.7.w7)
  • Some species, such as mute swans, dabbling ducks and some gulls are relatively easy to keep in captivity. (J313.1.w1)
  • If capture and transport between pens/enclosures is required, this should be carried out gently and quietly. (J311.9.w1)
  • Catching with long-handled nets is recommended. (J311.9.w1)

Cleanliness and hygiene

A high standard of cleanliness and order should be maintained throughout the rehabilitation area. (D135.7.w7)

  • Strict adherence to adequate hygiene and quarantine principles are vital for the success of this stage of the rehabilitation process. The importance of hygiene and appropriate husbandry must be understood by all staff. (B363.Intro.w21)
  • Hygiene and quarantine protocols should be prominently displayed in the bird holding areas and in other appropriate areas such as lunch rooms. (B363.Intro.w21)
  • Washed birds should be handled with clean hands or using powder-free gloves, to avoid disturbing waterproofing. (B363.11.w11, D160.5.w5)
  • Once clean, in order to minimise the risk of re-oiling, birds should not be placed in housing which was previously used for oiled birds. (D160.6.w6)
Published Guidelines linked in Wildpro

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Birds may be moved into post-wash housing once they have been washed and are dry; they are generally moved within 24 hours of being washed (B23.38.w2), often they are introduced to these pools the day after washing. (B11.35.w3)

Post-washing indoor housing

After washing and before being moved to outdoor pens, housing is required separate from birds which have not yet been cleaned, in order to avoid recontamination. (D214.2.w2)

  • Pens for most species may be lined with newspaper. (D214.2.w2)
  • For species such as divers (loons), auks, scoters and others susceptible to developing keel or hock lesions, use of net-bottomed pens is preferred. If these are not available then foam, bubblewrap or crumpled newspaper may be used as substrates. (D214.2.w2)
  • N.B. Substrates which are not absorbent need to be changed frequently to avoid the birds' plumage becoming soiled with droppings. (D214.2.w2)
  • When birds are housed inside, tungsten filament, rather than fluorescent, lighting, in a natural photoperiod, is preferable to decrease stress and encourage feeding. (D214.2.w2)

Outdoor pen construction

Housing outdoors is essential prior to release, to ensure that the casualties are acclimatised to external temperatures (B363.11.w11) and are properly weatherproof. (P62.2.w1)

Knowledge of the normal ecology of the species in care is important to ensure that housing appropriate for each species is provided. (D159.III.w3) 

Regaining fitness is an important part of rehabilitation.

  • Enclosures should allow the occupants to swim, fly and wade, although it may not be possible to provide very large species with sufficient space for flying. (B363.11.w11)
  • Fitness will be increased by birds flapping vigorously at the water surface, even if they do not fly. (B363.11.w11)

Use of wire walls or floors should be avoided; these can damage feathers and bills and cause foot lesions. (D160.5.w5)

  • If wire is used it must be thick (15 gauge or 16 gauge, as rounded as possible, and without sharp edges. (P24.335.w21)
  • Chicken wire or similar is unsuitable. Birds climbing such wire will damage their feet and feathers, and feathers may also be damaged by contact with the wire while stretching their wings, flapping or flying. (P24.335.w21)


Outside enclosures should be designed to ensure that the housed casualties are safe, protected from inclement weather and predators, and cannot escape. (D133.5.w5)

  • Double-doors are recommended to reduce the risk of escape, unless the design of the enclosure (the door being a continuation upward from the pool) makes this impractical. (D133.5.w5)
  • Outside enclosures need to be netted over to prevent animals from escaping. (D159.III.w3, J311.9.w1)

Temperature and Ventilation:

  • An ambient temperature of 20 to 25C is appropriate once birds have completed the washing process. (P24.327.w4, P24.335.w12)
  • Ideally, a temperature gradient is provided. (P24.335.w12)
  • It is important to ensure that birds are acclimatised to the outside temperature before they are released; this must be done gradually. (D135.7.w7, P24.335.w12)
    • Individuals which have been indoors for a prolonged period should not be moved outside during extremes of temperature. (B363.11.w11)
    • Initially birds should be given access to outdoor enclosures only during the day. (B363.11.w11)
    • When first moved into outdoor enclosures, birds should be kept under close supervision and returned to an indoor enclosure if found shivering or showing distress. (B363.11.w11)
      • Such individuals are placed outside then returned indoors as often as necessary until they remain waterproof and appear comfortable in outside temperatures for prolonged periods. (B363.11.w11)
      • Several days are usually required before birds can be left outdoors overnight. (B363.11.w11)
    • It must be appreciated that a bird's adaptation to cold winter or hot summer temperatures may be reduced after only one or two days inside in a different temperature. (P14.1.w16)
  • Pens must be well ventilated. (D135.7.w7, P24.335.w12)
  • Draughts should be prevented. (P24.335.w12)
    • Some shelter should be provided from prevailing winds, particularly in harsh climates. (B363.11.w11)
  • Shaded areas must be provided. (P24.335.w21)

Substrates and Perches:

  • Non-slippery and non-abrasive substrates are required. Soft rubber matting or fine clean sand may be appropriate. (P24.327.w4, P24.335.w12)
  • Substrates must be easily cleaned or replaced. (P24.327.w4, P24.335.w12)
  • Pools should be surrounded by an area of suitable substrate such as pea gravel or pea gravel/sand mixture for marshland species such as herons, egrets, coots and rails. (D133.5.w5)
  • If possible there should be a choice of at least two different substrates and/or perches for all birds to reduce the risk of foot/leg/skin problems. (D135.7.w7)
  • Concrete floors should be avoided. (D135.7.w7)


Perches should be provided as appropriate. (D160.6.w6) 

  • Perches should be chosen/designed depending on the natural history of the bird species. (D133.5.w5, P24.335.w12)
  • Species which will use perches if provided include raptors, marsh birds and shore birds. (D133.5.w5)
  • The diameter of branches or covered poles must be sufficiently large to prevent the bird's foot reaching all the way around and possible self-injury by the talons. (D133.5.w5)
  • Perch surfaces should be uneven, not smooth, and should be of varying diameters, not all of the same diameter. (D133.5.w5)
  • Perches should be placed sufficiently far from the roof of the enclosure, and so that birds can stretch its wings up and out while on the perch. (P24.335.w21)
  • Natural branches may be used or perching surfaces may be covered with sisal rope or astroturf with large curl-shaped bristles. (D133.5.w5)
  • Irregularly-shaped rocks are recommended for alcids. (D133.5.w5)
  • A net platform slanting upward from the water is suitable for ducks, geese, cormorants and grebes. (D133.5.w5)

Importance of water access

  • Access to water for swimming is important for full return to waterproof status for all aquatic and semi-aquatic birds. Once on water, birds will preen and restore the perfect alignment of the feathers which makes the plumage water repellant. (D60.7.w7, B188, D135.7.w7, P24.327.w4, P24.335.w12)
    • Swimming also stimulates appetite and motor activity. (B188)
    • Lack of access to clean water for swimming may lead to faecal soiling of the feathers with resultant loss of waterproofing. (D60.7.w7)
  • Birds on pools should have access to haul-out platforms and perches at all times except when being tested for waterproofing. (B363.11.w11)
  • Not too many birds should be placed on one pool, as some individuals may prevent others from using the water properly. (B188)
  • Waterproof aquatic birds should be housed on outdoor pools all the time from cleaning to release. (D159.III.w3)
Water quality:
  • Maintaining clean water is very important; dirty water will result in decreased waterproofing. (B363.11.w11, B365.75.w75, D214.2.w2)
    • Water may become soiled with food (e.g. oil from oily fish) as well as with bird excreta which contains fish oils. (B363.11.w11, D214.2.w2, P14.5.w5)
    • Pure water has a surface tension of 72 mN/m-1; lowering the surface tension to somewhere in the range 38-50 mN/m-1 will allow wetting of feathers. For birds in moult, water may penetrate at higher surface tension levels (49-58 mN/m-1 for moulting Aythya affinis - Lesser scaup. (J318.24.w1)
    • Food, droppings, and algae can all lower the surface tension of water, leading to wetting of birds. (J311.9.w1)
  • Pools for aquatic birds should have a constant water flow with surface skimming (i.e. water drains out of the pool by overflow from the surface) to ensure that any oil or detergent contamination of the water, and any surface debris, is removed rapidly. (B11.35.w3, B363.11.w11, B365.75.w75, D133.5.w5, D135.7.w7, J311.9.w1)
    • Complete water turnover at least every four hours is suggested. (D160.5.w5)
    • A filtration system may be used instead of or as well as constant overflow. (B23.38.w2)
    • Filtration combined with a pool vacuum cleaner is suggested for keeping large pools clean. (B188)
    • Large debris should be removed at least once daily, using pool cleaning nets. (D159.III.w3)
    • Fine debris should be siphoned from each pool at least once daily. (B363.11.w11, D133.5.w5, D159.III.w3)
    • While small amounts of fish may remain in the pool after feeding, allowing too much fish to remain should be avoided, as this may lead to oiling of the pools, and thus the feathers. (P14.5.w5)
    • For pelagic species in particular the water quality must be impeccable to ensure that feathers of these species do not become contaminated with fish oil either directly or via faeces. (D133.5.w5, D160.5.w5, J29.8.w1)
  • Pool sides should be easy to clean. (B11.35.w3)
  • Water of 2-3 grains hardness (30-50 mg/L) is recommended, at least for the first 24-48 hours after the washing process, to prevent binding of minerals with detergent resulting in the formation of microscopic calcium carbonate deposits on the feathers, which disrupts feather structure and therefore waterproofing. (D133.6.w6, B23.38.w2, J29.8.w1); 2.5-3.5 grains. (D135.7.w7); 2.5-3.5 grains/ 30-50 mg/L. (B188)
  • For marine species, to reactivate the salt glands, the water may gradually be artificially salted, gradually increasing salinity by adding sea salt from aquarium shops, until a salinity of about 3% (similar to sea water) is reached. (B363.11.w11)
    • Alternatively, salt is provided in food. (B363.11.w11) See section below: Feeding, Hydration and Salting
  • Small pools must be cleaned and refilled whenever they becomes dirty; this may require cleaning several times a day. (B188, D135.7.w7, J311.9.w1)
Pool size and depth for aquatic and semi-aquatic birds
  • The depth of the water should be sufficient to allow normal wading, swimming and diving behaviour of the species. (D133.5.w5, P24.327.w4, P24.335.w12)
    • At least 36 inches deep for larger pelagic species and diving birds such as divers (loons), guillemots (murres) and grebes, as well as large geese and swans. (D133.5.w5, J29.8.w1, J311.9.w1 ); more than 30 inches (76cm) may be required for some species. (D135.7.w7) Two feet (60 cm) deep is sufficient for surface feeding ducks and small geese. (J311.9.w1)
  • Pools need to be at least two to three metres square and 0.4 m deep for medium-sized birds such as auks. (D28, D214.2.w2)
    • The pool should have a shelf around the edge. (D214.2.w2)
  • Pools at least 10-12 feet in diameter will be required for the larger pelagic species. (D133.5.w5); at least 12 feet diameter (J29.8.w1)
  • Deep water is required to encourage large birds to flap their wings, swim and dive, increasing their general fitness and muscle tone even if there is insufficient room for large birds to fly. (B363.11.w11)
  • Dabbling ducks, gulls, terns, herons and similar species should be provided with pools such as children's paddling pools (kiddie pools) providing 14-16 inch deep (35-40 cm) water. (D135.7.w7, J311.9.w1)
  • Shallow water should be provided for waders. (D133.5.w5)
Platforms, ramps and haul-out areas
  • Birds must be able to enter and exit the water easily. Gently sloping pool sides allow easy exit for birds which become wet. (B11.35.w3); alternatively pools may be provided with ramps or platforms for birds to haul out onto. (B23.38.w2)
    • Pools within enclosures should be easily accessible via a ramp; easy egress from the pool should be provided similarly. (D135.7.w7)
    • When pools cover the whole enclosure area, haul-out areas are needed within each pool; cushioned platforms or floating boards may be provided as haul-out areas. (D214.2.w2, D135.7.w7, D159.III.w3, J311.9.w1)
  • Most water birds will readily make use of a pool if it is provided and will exit to preen when they start getting wet. (B23.38.w2)
    • Repeated swimming and then preening results in realignment of the feathers and restoration of the normal waterproof surface. (B23.38.w2)

Pools for swimming/waterproofing sessions 

  • If only limited pens with pools for swimming are available, it may be necessary to house birds in outdoor enclosure without full access to pools and transport them to pools daily for swimming. This is not ideal since it requires repeated catching of birds, with attendant stress and risk of feather damage, and also increases the risk of disease transmission between groups of bird. (B363.11.w11)
    • If permanent access to a pool for swimming cannot be provided then access to small wading pools should be provided at all times. Even small pools in which the birds can wade and preen will be beneficial. (B363.11.w11)
    • Birds should be placed on a swimming pool and left until they show signs of water penetration (shivering, loss of buoyancy, attempts to leave the pool), then lifted out with a long-handled net and placed in a warm sheltered area to dry. Each group of birds should be offered as many swim sessions each day as possible, allowing time for drying in between, and constantly supervised while on the pool. (B188)
Warm water pools
  • Warm water pools should be used for birds which need to be maintained on water to avoid problems related to captivity, but are not yet ready for cold water pools. A haul-out area can be provided if the birds are not completely waterproof. (D133.5.w5)

Water provision for terrestrial birds

  • Terrestrial and wading birds should be given access to fresh water for drinking and bathing. (D160.5.w5)
  • A flat pan of water can be provided to allow bathing; the size of the water pan should fit the size of the bird. (J311.9.w1)
  • Misting birds with water e.g. using a spray bottle or a fine mist attachment for a garden hose) two or three times daily will stimulate preening and is also useful for evaluating waterproofing in terrestrial and wading birds. (B23.38.w2, D160.5.w5, J311.9.w1)

Privacy, hiding places and stocking density :

  • Pens should be placed in areas with limited human access, human traffic past pens should be minimised and if possible visual barriers should be present to minimise stress to the birds from seeing humans. (D133.5.w5, P24.335.w12)
  • Hiding places such as boxes or curtained areas should be available in large pens. (D135.7.w7, P24.335.w12)
    • "Hiding places" in the form of bunches of branches placed in corners should be provided for species such as bitterns, crakes and rails. (P24.327.w4, P24.335.w12)
    • Towels or other cloths used to provide hiding areas must not have frayed edges which birds could get caught in. (P24.335.w21)
  • Gregarious species should be group housed, but not overcrowded (suggested area 1 square metre per bird). (B23.38.w2, P24.335.w12)
    • Birds of aggressive or solitary species need to be housed individually. (D135.5.w5, P24.335.w12)
    • Care should be taken not to place natural predators and prey or competitor species, close to one another. (P24.335.w12)
    • Consideration should be given to housing males and females separately from one another, for example if females show stress and reduced feeding behaviour in mixed groups. (P14.5.w5)
  • Note: Aggressive behaviour between occupants is more likely if pens are overstocked. (D135.7.w7)
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Feeding, Hydration and Salting of Birds

During the post-washing rehabilitation period, oiled birds must be provided with the appropriate nutrition to allow them to regain lost weight and fitness.


  • Birds which have been cleaned have access to water in pools for drinking and no longer require additional hydration. (D133.6.w6, J29.8.w1)


  • Once on outside pools birds generally become self-feeding within a few days. (D133.6.w6, J29.8.w1)
Food quantity
  • Birds must be fed enough food to regain lost body weight. (D160.5.w5) 
    • The amount of food required will vary depending on the nutritional value of the food, and the bird's metabolism, body condition and health status. (D160.5.w5)
    • Careful calculation of the daily calorie and specific nutrient needs is required; each individual must then be provided with the required nutrition. (P14.3.w19)
    • Note: Basal metabolic rate of many marine birds is higher than would be predicted from standard allometric equations for non-passerine birds. (J58.137.w1)
    • Some weight loss may occur when birds are first moved outdoors, probably due to increased exercise and to external temperature variations. With adequate, good quality food, this lost weight should be regained in a few days. (B363.11.w11)

Food type and presentation

  • The right type of food must be provided, depending on the bird species and their natural diet. (D160.5.w5, P62.1.w1)
  • Food should be provided in a manner which avoids re-soiling of feathers. (D160.5.w5)
    • Shallow trays of fish may be provided away from the water to reduce contamination of the pool with fish oils. (B11.35.w3)
    • N.B. Fish should not be offered to birds which have been cleaned but are still housed out of pools. (J29.8.w1)
  • NOTE: Presentation of food in a bowl is not normal for wild birds. Stimulation to eat may be required. (D135.7.w7) 
    • Fish (e.g. smelt) is tossed and the birds observed for self-feeding. (D133.6.w6, J29.8.w1)
    • Food may be placed in large, flat clear glass dishes, water may be poured over food to encourage eating or mealworms placed on top of gruel or pellets. In some places a few live fish may provided in water on top of larger thawed fish. (D135.7.w7)
    • Feeding may be encouraged by making the fish move - thrown at the bird or into the water, moved in water using long tongs. (B363.9.w9)
  • Birds on pools should be fed non-oily fish in a manner mimicking their natural feeding method. (D160.5.w5)
  • Smelt is the preferred fish at this stage. (D159.III.w3)
  • Feeding very oily fish (e.g. sardines, tuna, mackerel) should be avoided, to minimise the risk of recontamination of plumage from oily faeces. (B23.38.w2)
  • For dabbling ducks, grains, pelleted foods designed for ducks and gruels of such pellets may be provided. (D135.7.w7)
  • For swans and geese, chopped green food, wheat and appropriate pelleted foods may be given. (D214.2.w2)
  • Live food such as earthworms or mealworms may be used to stimulate feeding of insectivorous or partially insectivorous birds. (B363.9.w9)
Feeding frequency
  • Food should be provided throughout the day; (D159.III.w3) Food should be provided ad libitum, (D135.7.w7, D214.2.w2) freshly prepared and replaced with fresh food as required in each pen, two to four times daily. (D135.7.w7)
  • Spilled food must be cleaned up daily and not left to dry out or become mouldy. D135.7.w7)
  • Care should be taken to ensure that all the birds within a pool or enclosure have the opportunity to feed. (D160.6.w6)
Gavage feeding
  • Gavage-feeding may be required for some birds which do not self-feed, at least for the first few days until self-feeding occurs. (D133.6.w6, J29.8.w1)
    • Assisted feeding must continue until the individual is self-feeding. (P24.327.w4, P24.335.w12)
      • Note that some seabirds may not feed themselves while in captivity. (P24.335.w12)
    • A suggested diet if gavage is required is: 3 cups of Mazuri Flamingo Breeder pellets, 3.5 cups of water, one multivitamin tablet (Centrum vitamin, Lederle Consumer Health), 100 mg thiamine table. The dry ingredients are ground in a blender, then the water added and the mixture blended for five minutes until smooth. This slurry provides approximately 1 kcal per mL of the mixture. The time and date of mixing should be noted and any unused mixture discarded after 24 hours. About 50 mL per kg bodyweight can be given at one time. (J29.8.w1)
Food storage, food preparation and vitamin supplementation
  • Food must be properly stored in airtight containers, refrigerators, freezers etc. as appropriate to avoid spoilage and contamination, and separate from food for human consumption. (D160.5.w5)
  • The temperature of refrigerators, freezers, thawing tubs and food handling areas should be monitored. (D133.5.w5, D160.5.w5)
  • N.B. Cleanliness is essential in food preparation. (D133.5.w5)
    • Personnel handling foods should wash their hands before starting work, at each rest break and when their work shift finishes. (D133.5.w5)
    • All containers, utensils etc. should be thoroughly washed and disinfected between use: (D133.5.w5)
      • Wash in warm soapy water to remove gross contaminants; (D133.5.w5)
      • Then soak in dilute disinfectant solution (e.g. chlorhexiderm or a quaternary ammonium compound) for at least twenty minutes; (D133.5.w5)
      • Rinse all objects after disinfection before reusing. (D133.5.w5)
  • Food should usually be used on the same day it has been prepared. (D133.5.w5)
    • N.B. Gavage mixes should be used on the day of preparation or refrigerated overnight and used within 24 hours. (D133.5.w5)
      • The time and date of mixing should be noted and written on the container, and any unused slurry discarded after 24 hours. (D133.5.w5, J29.8.w1)
  • Frozen fish, stored frozen for at least six weeks, may be preferred to fresh fish, since this treatment kills parasites. (B363.9.w9, P24.327.w26)
    • Fish may be stored frozen for up to three months at -18 C or below. (B363.9.w9)
    • Fish should be used within one month if stored in a domestic freezer; if stored commercially at minus 30 C, then white-fleshed fish may be stored for up to six months while red-fleshed fish (e.g. mackerel, mullet) should be stored for no more than four months. (P24.327.w26)
  • Frozen fish should be thawed before use, preferably slowly in a closed container (to minimise loss of moisture) in a refrigerator. (B363.9.w9)
    • Thawing fish at room temperature or in water, leads to loss of water-soluble nutrients. (B363.9.w9)
    • Personnel involved in food preparation should be trained in the proper procedures for thawing fish. (V.w73)
  • Thawed fish should be kept refrigerated and discarded if not used within one day. (B363.9.w9)
  • Fish diets must be supplemented with vitamins; several commercial tablets designed for this purpose are available. (B363.9.w9, P24.327.w4)
    • Addition of thiamine at 25 to 30 mg/kg fish is recommended, since thiaminases are often present leading to reduced levels of thiamine (vitamin B1) in dead fish. (P24.327.w26)
    • Fish which have not been stored in the correct conditions, particularly oily fish such as mackerel or tuna, may be vitamin E deficient; 100 international units of vitamin E can be added per kilogram of fish if such incorrect storage is suspected. (P24.327.w26)
    • Care should be taken to avoid over supplementation with vitamins A, D or E, and resultant toxicity. (P24.327.w26)
  • N.B. Food for human consumption must be stored separately from animal foods. (D133.5.w5)


  • Food provided and food eaten (or food not eaten) should be recorded on Daily Care Sheets for each pen. (D135.7.w7, D160.5.w5) or for individual birds when dealing with smaller numbers of casualties. (D160.5.w5)

Salting of pelagic birds:

Pelagic birds must be salted prior to release if they have been kept off salt water for more than a week (B365.75.w75) or 10 days. (B363.9.w9, P24.327.w4)

  • If kept in fresh water, the salt gland of these species atrophies and if a birds is released with the gland non-functional the bird will rapidly dehydrate and die. (P24.327.w4, P24.335.w12, J311.10.w1)
  • Natural sea water can be used in pools. (B365.75.w75)
  • Pool water may be salinated, preferably using artificial sea salts from good pet stores. (B365.75.w75)
  • Salt tablets can be given in fish, at 100 mg/kg body weight per day per bird. (B188, P24.327.w4, P24.335.w12)
  • Granular sea salt (100 mg per kg body weight per day) may be added to food. (D135.9.w9)
  • Note: where birds have been maintained on fresh water, salting should be carried out gradually. (B365.75.w75) Suggested methods of salting include:
    • Pool water may be gradually made saline with an increase of 0.5% every three or four days until about 3% is reached. (B365.75.w75)
    • Initially salt supplements should be given at 25% of the maximum dosage, i.e. at 25 g/kg bodyweight, with increases every three to four days if this is tolerated without ill effects. (B363.9.w9)
    • Individuals which are not eating well, or which are anyway being gavaged for other reasons, may be given salt in the liquid feed, at 1% concentration on the first day, 2% concentration on the second day, 3% on the third day and thereafter if gavage must be continued, or moving to salt in the food if the bird is eating. (D135.9.w9)
    • Birds may be tubed with a 1% salt concentration about every three hours on the first day, then if there have been no signs of salt toxicity, with 3% the following day. (J311.10.w1)
  • When salting is started, birds must be observed carefully for signs of salt toxicity (. Signs of toxicity include tremors, convulsions, lethargy and loss of appetite. If such signs are seen the affected bird(s) should be given fresh water orally by gavage or may be given sterile water intravenously. (B363.9.w9, B365.75.w75, J311.10.w1)
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Monitoring and Veterinary Procedures for Birds

  • Washed birds should be handled with clean hands or using powder-free gloves, to avoid disturbing waterproofing. (B363.11.w11, D160.5.w5)
  • Clean, non-contaminated equipment must be used for all assessment of clean birds. (D160.5.w5)
  • Note: birds requiring extra rehabilitative care before release, and kept hospitalised for some time, may need another wash to restore waterproofing before release. (D160.6.w6)

Daily observation

  • It is important that personnel making the observation are experienced in observing bird behaviour and know the signs indicative of hypothermia. (D159.III.w3)
  • Birds in each pen should be observed daily, with condition, activity level, quantity and quality of droppings, amount of food eaten observed. The first observation should take place early in the day. (D135.7.w7)
  • Any bird which appears unwell must be isolated, particularly if a contagious disease is suspected. (P24.335.w12)
  • Birds should be monitored for general behaviour, including feeding activities and social interactions, and for continued waterproof status. (D160.5.w5) 
    • Fit birds should be active and alert, eat well, preen actively, swim, dive (as appropriate for the species) and interact with conspecifics (as appropriate for the species). (B363.11.w11)
    • Stressed or unfit individuals will not show normal behaviour. (B363.11.w11)
    • Confident movement around the enclosure should be seen, without any signs of neurological deficit. (B363.11.w11)
  • Sufficient size and depth of pool are required for observation of diving behaviour, feeding habits and waterproof status. (J29.8.w1)
  • Shivering (which may be seen as ripples in the water out from a bird), tremors/convulsions, head drooping, listing, panting, wings not held normally tight to the body, unusual activity or inactivity and changes in the colour and consistency of droppings should be noted. (D135.7.w7)
  • Records: Observations should be recorded on the appropriate forms, including notes of activities such as self feeding and swimming. Unusual findings should additionally be reported to the shift supervisor. (D135.7.w7)
Failure of waterproofing
  • Excessive preening, shivering, fluffing up, agitated behaviour, reduced buoyancy (low position in the water), tail hanging in the water and attempts to leave the water suggest failure of waterproofing. (B188, B363.11.w11, D133.6.w6, D159.III.w3, J29.8.w1, J311.9.w1)
  • Birds showing such signs need to be removed from the water using a long-handled net. (B188, B363.11.w11, J311.9.w1) and placed in a warm sheltered area to dry. (B188); should be returned to the drying room. (B363.11.w11, D159.III.w3), or onto warm water pools. (D159.III.w3)
    • Once the bird has preened and is dry, it is placed outside again. (B363.11.w11, D159.III.w3, J311.9.w1)
    • Reasons for failure of full waterproofing are provided in Release of Oiled Wildlife - Assessment for Release
  • Predetermined areas (e.g. top of the head, neck, chest, top of wing, underside of wing, sides underneath the wings, back, legs, around the vent, should be checked for signs of wetting. (B363.11.w11)
  • Note: Floating low in the water, generally a sign of inadequate waterproofing, may also indicate diseases such as aspergillosis (see: Aspergillosis in Birds (with special reference to Waterfowl)).
  • Misting birds with water e.g. using a spray bottle or a fine mist attachment for a garden hose) two or three times daily is useful for evaluating waterproofing in terrestrial and wading birds: in waterproof birds the water will run off the feathers in beads, rather than soaking into the feathers. (B23.38.w2, D160.5.w5, J311.9.w1)

Veterinary procedures

  • Antifungal medication may be discontinued since ventilation is good in outdoor enclosures and exposure to fungal spores should be low. (D133.6.w6)
  • Birds should be weighed regularly (e.g. every 4-6 days). (D133.6.w6, D160.5.w5, J29.8.w1); assessment of muscle condition (tone) should be made also. (D160.6.w6)
  • Birds should be blood sampled regularly (e.g. every 4-6 days). (D133.6.w, J29.8.w1); PCV and total proteins should be assessed. (D160.5.w5)
  • Consider anthelmintic therapy for birds, particularly juveniles, which are eating well but failing to gain weight. Note that some species are more likely to suffer from excess parasite burdens than are others. (V.w78)
Note: Handling is an additional stressor for wild birds. It has been suggested that, particularly for species such as guillemots (Uria aalge - Common murre), which are easily stressed, handling after washing and before release should be minimised and if possible eliminated until the birds are caught for transportation to the release site, with progress determined based on visual assessment of the birds. (D184)

Note: Final assessment of the suitability of individual casualties for release is considered in Release of Oiled Wildlife - Assessment for Release

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Post-washing Care of Mammals

As with birds, mammals require a variable period of rehabilitation after washing before they are fit for release. 
  • For Enhydra lutris - Sea otters, studies on energy requirements following oiling and cleaning indicated that, following cleaning, at least one to two weeks should be allowed for the animals to restore fur insulation and recover from the stresses of oiling and cleaning. Longer would be required in individuals with secondary problems such as disease, dehydration or reduced feeding. (J30.66.w1)



  • Enhydra lutris - Sea otters may be maintained, two to a pen, in saltwater pools 4 ft by 4 ft by 2 ft, with haulout areas, until the pelage has regained insulating ability, then in larger pools with other otters, then finally, when stable and foraging, into prerelease pens, at least 12 by 24 by 8 ft, in the sea. (B22.33.w9)
    • Initial post-wash housing for sea otters uses pens with one pool and two haul out areas to house two otters. Water in the pools is chlorine-free salt water with a high exchange rate (five gallons per minute for a 150 gallon pool) and with drain skimmers at water surface level to remove debris. (D208.6.w6)
    • Provision of both water and a haul-out area appears to be extremely important. (B368.8.w8)
    • Monitoring is required 24 hours a day during rehabilitation, by personnel familiar with normal behaviour of sea otters and who therefore are able to recognise signs of distress in the otters. (D208.6.w6)
    • Hypothermia is a common problem due to reduced insulation of the fur. (D208.6.w6)
    • Individuals showing signs of hypothermia, difficulty in hauling out, or seizures, need to be immediately removed from the water for veterinary evaluation. (D208.6.w6)
    • With improving health and fur condition, sea otters can be moved into larger pools or floating holding pens. (D208.6.w6)
  • Maintenance in water with a temperature above 20 C is recommended for several days following oiling and cleaning, since about eight days are required for a return of the normal insulative quality of the fur. (J30.60.w1)
  • N.B. It is essential that otters are housed in a low-stress environment in which they will groom properly and restore the water repellent quality of the fur. (B335.6.w6)


  • Housing should provide sufficient room for the less sociable species to maintain normal distances between individuals. (P14.3.w15)
  • Adult males should not be housed together in the breeding season. (P14.2.w5, P14.3.w15)
  • Observation is recommended when individuals are first put into the same pen, with changes of pen mate if any appear incompatible. (P14.2.w5, P14.3.w15)
  • Access to water, preferably with a depth of at least 1 m, should be provided if possible for swimming and grooming. (P14.2.w5, P14.3.w15)



  • Enhydra lutris - Sea otters (adults) should be fed high quality fish (e.g. herring) and shellfish, with multivitamin supplements plus additional vitamin E. (D208.6.w6)
  • Herring is recommended for feeding, due to its high fat level allowing maximum weight gain. (P14.2.w5, P14.3.w15)
  • Fish should be supplemented with vitamins (multivitamins at one tablet per 70 kg bodyweight once daily, plus additional vitamin E at 400 IU per 150 kg bodyweight, once daily). (P14.2.w5, P14.3.w15)
  • Salt supplements should also be given, at 3 g salt per kg fish, once to three times daily. (P14.3.w15)
  • If an individual is anorexic, gavage feeding may be required, using fish blended with water for adults and appropriate milk formulae for pups. (P14.2.w5)
  • Reduced regularity of feeding may be beneficial in the days just before release to decrease dependence on humans for food. (P14.3.w15)

Daily observation

General health and specific disease screening

  • Prophylactic treatment for internal parasites is recommended in seals. (P14.3.w15)
  • Blood samples may be taken for screening for specific diseases, e.g. in harbour seal (Phoca vitulina - Common seal) pups, for parvovirus and canine distemper virus, as well as for standard haematology and biochemistry panels. (B377.13.w13)

Note: Final assessment of the suitability of individual casualties for release is considered in Release of Oiled Wildlife - Assessment for Release

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Post-washing Care of Reptiles

The following provides an indication of post-washing care which may be required specifically related to oiling.
  • For western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family)) following oiling with diesel, water in the individual aquaria was changed several times daily until the water no longer showed any sheen of oil; after this time it was changed daily. (P14.4.w3)
  • For western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family)) following oiling with diesel, water in outside pens was filtered by a combined biological and mechanical filtration system, and large pieces of food and debris were removed with a net daily. (P14.4.w3)
  • For western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family)) following oiling with diesel, anorexic individuals were force fed by gastric incubation with Hills A/D mixed with warm water at 6.6 to 8.8 mL/kg three or four times daily. (P14.4.w3)
  • The following suggestions were made for care of freshwater chelonia following diesel exposure: (P14.4.w3)
    • Provide flow-through water or very frequent water changes until all signs of diesel have gone. (P14.4.w3)
    • Provide treatment for diesel exposure of the eyes, nares, skin and shell. (P14.4.w3)
    • Ensure the highest standard of supportive care including: (P14.4.w3)
      • a high quality, varied and complete diet; (P14.4.w3)
      • clean environment with correct heat and light provision; (P14.4.w3)
      • individual housing; (P14.4.w3)
      • strict quarantine; (P14.4.w3)
      • daily monitoring and recording of the health status of each individual; (P14.4.w3)
      • injectable vitamin B complex (without vitamin A) and vitamin C, to counteract the effects of stress, toxins and anaemia. (P14.4.w3)
    • Do not use shell notching as a form of identification. (P14.4.w3)
    • Treat any signs of clinical disease aggressively. (P14.4.w3)
    • For sea turtles, supportive therapy such as fluids is suggested, as required. (D228.5.w5)
      • Up to six, low-volume tube feedings per day may be required for individuals with low blood glucose, while those with normal glucose levels may be fed only three or four times a day. Frequency of feeding can be reduced as weight stabilises and increases. Note: Initially, it may only be possible to give 10 ml at a time to a turtle of 3 to 4 kg bodyweight, due to the turtle's anatomy, with a left turn of the oesophagus to enter the stomach. (B413.6.w1)
    • For sea turtles, holding for at least 10 to 14 days in isoosmotic one-third seawater and monitoring the osmolarity of the secretion of the salt glands has been suggested to ensure that this secretion has returned to normal before release. (D228.5.w5)

Veterinary care:

  • Injections of B-vitamins (without vitamin A) and vitamin C were given every three days, into the left and right forelimbs alternatively, for supportive care and to act as an appetite stimulant, in western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family))) every three days following oiling with diesel. (P14.4.w3)
  • Gentamicin ophthalmic ointment was applied to the eyes if these were inflamed, and gentamicin ophthalmic solution to the nares, of chelonia (western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family)) twice daily for about two weeks following oiling with diesel. (P14.4.w3)
  • Gentamicin ophthalmic solution was given intranasally in chelonia (western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family))) showing respiratory distress, twice daily for about two weeks following oiling with diesel. (P14.4.w3)
  • For chelonia (western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family)) showing skin and shell lesions following oiling with diesel, 2% chlorhexiderm mixed 1:10 to 1:50 with water was applied twice daily. (P14.4.w3)
  • Parenteral antibiotics were given to western pond turtles Clemmys marmorata (Emydidae - Pond turtles (Family) with respiratory distress, skin lesions or shell lesions following oiling with diesel. (P14.4.w3)
  • For sea turtles, it has been suggested that serial blood samples should be taken to direct treatment. (B413.6.w1, D228.5.w5)
  • For sea turtles, the output of the salt glands should be assessed. (D228.5.w5)

Further information on husbandry of reptiles may be found in Accommodation of Casualty Reptiles (Techniques) and Feeding of Casualty Reptiles (Techniques)

Note: Final assessment of the suitability of individual casualties for release is considered in Release of Oiled Wildlife - Assessment for Release

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Post-washing Care of Amphibians

No specific information is available on the post-washing care of oiled amphibians. General information on the care of casualty amphibians is provided in:

Note: Final assessment of the suitability of individual casualties for release is considered in Release of Oiled Wildlife - Assessment for Release

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Quarantine and Isolation


The potential for rapid spread of pathogens to large number of animals is increased when large numbers of animals are being rehabilitated in one place a one time. (P24.327.w4)

Quarantine is a major tool for reducing the risk of disease transmission. Routine quarantine measures which may be used to minimise the risk of spread of infectious disease include:

  • Maintaining animals in batches through the whole rehabilitation process, with no new animals introduced into an existing group. (P24.327.w4, P24.335.w12)
  • General hygiene and appropriate use of disinfectants. (P24.327.w4, P24.335.w1224.327.w4)
  • Minimising human traffic. (P24.327.w4, P24.335.w12)
  • Changes of clothing when moving between work areas/pens/buildings. (P24.327.w4, P24.335.w12)
  • Adequate disinfection of utensils such as brooms, rakes and shovels if these are shared between pens. (P24.327.w4, P24.335.w12


Oiled birds are likely to be immunocompromised due to stress and/or the toxic effects of petroleum products, and are therefore more susceptible to infectious diseases. (D133.5.w5, P24.335.w12)

  • Any bird suspected of carrying a contagious infection (i.e. any bird showing signs compatible with an infectious disease) should be isolated. (D32.3.w3, D135.5.w5, P24.335.w12)
  • If a bird with a suspected or confirmed infectious disease is to be treated it must be maintained in isolation, in an area with ventilation separate from that of the other casualties. (D133.5.w5)
  • Euthanasia should be considered for individuals with infectious disease; (B363.8.w8) these may present a potential health risk to other animals. (D32.3.w3)
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Authors & Referees

Authors Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Dr Virginia Pierce (V.w73)

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