& Management / UK
Wildlife Casualty Management / Techniques:
information should be read in association with Wildlife Casualty Release which contains
background information together with links to the Electronic Library and Organisations (UK
Contacts). The related Species pages contain similar linkages.
||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: Aix
galericulata - Mandarin duck; Anas
acuta - Northern pintail, Anas
clypeata - Northern shoveler, Anas
crecca - Common teal, Anas
penelope - Eurasian wigeon, Anas
platyrhynchos - Mallard, Anas
strepera - Gadwall, Anas
querquedula - Garganey, Anser
albifrons - Greater white-fronted goose, Anser
anser - Greylag goose, Anser
brachyrhynchus - Pink-footed goose, Anser
erythropus - Lesser white-fronted goose, Anser
fabalis - Bean goose, Aythya
ferina - Common pochard, Aythya
fuligula - Tufted duck, Aythya
marila - Greater scaup, Branta
bernicla - Brent goose, Branta
canadensis - Canada goose, Branta
leucopsis - Barnacle goose, Bucephala
clangula - Common goldeneye, Clangula
hyemalis - Long-tailed duck, Cygnus
columbianus - Tundra swan, Cygnus
cygnus - Whooper swan, Cygnus
olor - Mute swan, Melanitta
fusca- White-winged scoter, Melanitta
nigra - Black scoter, Mergellus
albellus - Smew, Mergus
merganser - Common merganser, Mergus
serrator - Red-breasted merganser, Oxyura
jamaicensis - Ruddy duck, Somateria
mollissima - Common eider, Tadorna
tadorna - Common shelduck.
These species are from the family Anatidae.
It is important to consider the natural history of the species of waterfowl being
released. There is a great deal of difference between releasing waterfowl back onto lakes
in urban ponds or similar relatively sheltered situations, and releasing seaducks back to
the sea or migratory species to continue their migration.
- No pre-release preparation is required if these birds have been in care for a short
period of time.
- Birds which have been in care for more than a few days should be reacclimatize by
housing in an outside enclosure with an appropriate pool for a period of time (generally
about two weeks) before release.
- In dry summer weather, daily spraying of birds with water may be used to encourage
preening and ensure plumage is returned to normal waterproofing .
- Appropriate health checks should be carried out prior to release. A careful
assessment (risk analysis) must be made as to the risks of released animals introducing
novel pathogens (disease agents) into the wild population/environment.
- These pathogens may have been acquired from domestic animals, other wildlife casualties
or humans whilst the animal was in captivity.
- The health checks should be designed to
minimise the risk that pathogens posing a threat to wild populations of this or other
species will be introduced into the environment when the animal is released.
- Waterfowl must have adequate plumage with normal
waterproofing/weatherproofing, and must be acclimatised to outside environmental
conditions at the time of release.
- For most adult waterfowl waterproof status may be ascertained by maintaining the bird
outside with constant access to a pool of an appropriate size for swimming for one to two
weeks. The bird should not look wet or bedraggled at any time nor avoid the water nor swim
lower in the water than others of the same species.
- Hand-reared juveniles must not be released until after they have grown their first set
of proper feathers.
- It is particularly important to assess the waterproof status of birds which have been
in care due to oiling, and of seaducks presented for any reason.
- It may be possible to release swans with small areas of feather loss on the neck
(e.g. at a surgical site), but not if large areas of feathers are missing.(D3)
- Waterfowl must be capable of acquiring flight and sustaining flight at the time of
release, unless in moult.
- This is particularly important for migratory species but less important for sedentary
individuals released back to a habitat such as a park lake with safe islands for roosting.
- Waterfowl should be able to walk normally at the time of release.
- Leg injuries resulting in permanent lameness may prevent swans reaching sufficient speed
- Amputees of any waterfowl species are not suitable for release.
- Waterfowl must be able to swim normally at the time of release.
- Waterfowl must be able to feed normally on release.
- A bird with a damaged bill which has not fully mended is not suitable for release.
- Waterfowl must be able to preen normally at the time of release.
- Waterfowl being released must be at and maintaining an appropriate weight
for their species, age, sex and time of year.
- Birds being released during or immediately before the migratory season
must have sufficient reserves for migration (appropriate, higher-than-average weight).
- Birds released prior to the moult (during which waterfowl lose all their
flight feathers and are unable to fly) must have sufficient reserves for moulting and be
released at an appropriate safe site for the species during the moulting period.
- Birds must display appropriate behaviour, interacting with others of
their own species as normal and showing appropriate wariness of humans (neither imprinted
- The release of species listed in Schedule 9 of Wildlife
and Countryside Act 1981, including Canada geese (Branta
canadensis - Canada goose) and ruddy ducks (Oxyura
jamaicensis - Ruddy duck), and any other species
not normally resident in or visitors to Britain is prohibited (see below).
- It is important to remember that some of these species are migratory
or disperse following breeding.
- Individuals of migratory species released during or just before migration
must have sufficient body (fat) reserves for migration.
- The ability to sustain flight for long periods is particularly important for migratory
- Most casualties can be released back where they were found, if it is safe to do so (e.g.
not on a main road where the bird crash-landed).
- For non-sedentary waterfowl which have been maintained for more than a short time it is
important to consider whether the site at which the bird was found is an appropriate site
at a different time of year, related to e.g. migration, moulting grounds, breeding
- Release adult mute swans (Cygnus
olor - Mute swan) back into their own territory as soon as possible;
however, problems may arise if another swan has taken over the territory.(B203)
- Release juvenile mute swans (Cygnus
olor - Mute swan) into a non-breeding flock if possible.(B203)
- Avoid releasing female ducks such as mallard (Anas
platyrhynchos - Mallard) which have presented due to excessive mating
("gang rape") back to a site with a high density of drakes during the breeding
- Permission must be sought from the owner before birds are released onto
- The site must not make landing and/or take off difficult; this is
particularly important to assess for swans which require a relatively long run up to
- The site must not be adjacent to obvious hazards such as power lines or
- The site must provide an adequate natural food supply for the species
being released. For waterfowl this varies from grass for grazing species to fish for e.g.
mergansers. See the individual natural history pages for further details.(D3,
- A full investigation into the suitability of the site should be
undertaken if releasing onto a site not already inhabited by the species, in order to
determine that it is a suitable habitat. (D3,
- Release back into a habitat in which there is a consistent hazard (e.g. a
stretch of water which is frequently contaminated with oil, a water with a known lead
problem or a site with vandals shooting at birds) should be avoided. (P19.3.w6,
Timing of release:
- For migratory species which have been kept beyond the time of migration
from Britain it may be necessary to wait until the flocks are returning. If the bird has
spent more than a short time in care release should ideally take place a month
before migration in order to allow the bird to regain sufficient fitness for migration.(P24.233.w11)
- Consider the time of year related to risk of territorial conflict. (B203)
- Avoid releasing on a day when the release site is subject to excessive
disturbance such as an angling match or for public parks, weekends.(D3,
- Release on a fine day in a period of good weather if possible. (P19.3.w6,
- Release in the early morning to give the full day for the released bird
to orientate itself. (D3)
Type of release:
- Waterfowl are normally released by hard release.
- For waterfowl being released back to e.g. park lakes or similar areas, it is possible to
ensure that supplementary feeding is provided daily at the release site.
- If the casualty is naturally individually recognisable or has been marked (e.g.
with a ring or with a temporary colour mark on the feathers) it is possible to observe the
|Appropriate Use (?)
- Waterfowl being released into e.g. a park lake where they are fed by the public will
effectively have a soft release as they will be fed following release.
- Soft release is particularly important for hand reared animals, particularly of species
which need to learn about their surroundings (e.g. food sources) and/or learn survival
skills such as hunting.
- Soft release is also suitable for animals which have been in care for prolonged periods.
- Soft release may compensate for difficulties of newly released animals finding food and
shelter, particularly in a new environment and/or at a time of reduced physical
- Hard release is most appropriate for animals which have been held in captivity for only
a short time, for adult animals and for animals being released back into their own
- The individual animal must, at the the time of release, be healthy, have a reasonable
level of fitness and be able to fend for itself in the wild.
- Diurnal species should be released in the morning, giving them a full day to explore and
look for food and shelter before night fall.
- Nocturnal species should be released at night.
- Release should preferably take place during a period of fine weather.
- Preferably have all birds ringed before release - contact the British
Trust for Ornithology for details of local licensed bird ringers.(B156.15.w15,
- Observe following release, both immediately in the hours after release
and in the days following release if possible; individual identification makes this
|Complications/ Limitations / Risk
- Waterfowl should not be released back to their site of origin if this is clearly
hazardous or unsuitable, e.g. when an individual has presented after crash-landing on a
road or having been shot by vandals, or if the site of origin would encourage the bird to
take off into power lines. (D3,
- Hard release is least appropriate for juveniles which have been hand reared,
particularly species for which learning about their environment and/or social skills are
- Hard release may also be inappropriate for adults which have been maintained in
captivity for prolonged periods and/or are being released at a site distant from their
- Released animals may be at risk of contracting disease if there is an ongoing disease
problem in the wild population at the time of release.
- The wild population may be at risk from novel pathogens (disease agents) carried by a
rehabilitated animal. These pathogens may pose the greatest threat to free-ranging
populations if the animal is to be released at a site distant from its original location
therefore increasing the likelihood of spread of disease. It is important to remember that
the casualty wild animal may have acquired disease from domestic animals, other wildlife
casualties or humans whilst in captivity.
|Equipment / Chemicals required and Suppliers
|Expertise level / Ease of Use
- Knowledge of natural history including migration times and routes and sites used at
different times of year is required for correct decision making regarding release of
non-sedentary waterfowl being released after a long period in care.
- Local releases are not expensive, however release may be more expensive if the bird
needs to be transported some distance to an appropriate release site.
- Costs of appropriate health screening.
|Legal and Ethical Considerations
- The potential risks to the individual being released and to the wild population into
which it is being released (also to domestic animals) must be considered before release is
- The potential risk to humans and pets from habituated/tame individuals must be
- An offence may be committed under Section 1 of the Abandonment
of Animals Act 1960 if a released rehabilitated animal does not have a
reasonable chance of survival (i.e. a chance similar to its non-rehabilitated peers).
- This may include release at an unsuitable site, in the wrong territory, unfit, not
having learned to hunt, at the wrong time of year etc.
- Under the Wildlife
and Countryside Act 1981 Section 14 it is an offence for any person to
release without a licence or allow to escape into the wild any species which is
listed in Schedule 9 of the Act (including Canada geese (Branta
canadensis - Canada goose), ruddy ducks (Oxyura
jamaicensis - Ruddy duck), Carolina wood duck (Aix
sponsa - Wood duck) and Mandarin duck (Mandarin duck - Aix
galericulata)) or is not ordinarily resident in and is not a
regular visitor to Great Britain in a wild state. (W5.Jan01,
- In Britain bird ringing must be undertaken by someone with a British
Trust for Ornithology (BTO) ringing licence. (B118.20.w20,
||Becki Lawson and Suzanne Boardman
Sanctuary Code of Practice - full text incorporated), D27, V.w5,