||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,
- Assistance of experienced personnel should be obtained for release of birds of prey;
a local falconry or bird of prey expert should be consulted for advice.
- Falconry techniques may be used:
- Falconry techniques may be useful for conditioning adults following prolonged
- Falconry techniques may be useful for training and conditioning juveniles, so that they
come to associate hunting with feeding.
- Flying on a creance (the cord which secures the hawk in training) may be useful for
improving condition/ flight capability prior to release.
- Training a bird to fly to a hackboard, lure or kite is required for some
soft release methods.(D53)
- Placing birds in an aviary or building at the proposed release site and with a good view
over the surrounding area for about four to six weeks before release may be used for soft
release from such an aviary or building. (D53)
- 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.
- Birds must be able to walk, fly, see, feed and preen normally on release and
have sufficient fitness for sustained flight.
- A bird with a damaged bill which has not fully mended is not suitable for release.
- Birds of prey must be able to fly well and hunt efficiently.(J3.106.w1)
- There are differences in opinion regarding the exact requirements for release of
raptors. However the principle points are that following release the bird must be
physically able to pursue and catch prey and must be behaviourally suited for life in the
- In general, the bird must have a high degree of flying ability.
- Raptors with permanent damage to the wing limiting joint movement or the movement of the
radius over the ulna (synostosis) should not be released.(J3.106.w1)
- However some authors have indicated that raptors with some degree of
carpal and elbow joint restriction and some restriction of movement (sliding) of the
radius over the ulna may still be able to fly effectively. (J3.106.w3)
- Wing injuries are more likely to preclude release of aerial hunters and
migratory raptor species, which are completely reliant on precise, rapid or prolonged
flight, than sedentary perch hunters or scavengers.(J3.106.w1)
- Adults with flying and hunting experience are more likely to adapt effectively to some
flight impairment than are inexperienced juveniles.(J3.106.w1)
- Flying on a creance (a length of line to which the bird is attached while the other end
is wound round a stick held in the hand so that the bird cannot fly away) may be useful
for assessing flight capabilities, particularly following treatment of severe injuries.(J3.106.w2,
- Birds must have adequate plumage with normal
waterproofing/weatherproofing, and must be acclimatised to outside environmental
conditions at the time of release.
- Release is dependant on satisfactory plumage condition; imping may be used to repair
flight or tail feathers prior to release.(J23.23.w2)
- If feathers cannot be repaired it may be necessary to leave the bird in a
seclusion aviary (solid sides) until it moults out the damaged feathers before release is
- Birds must display appropriate behaviour, interacting with others of
their own species as normal and showing appropriate wariness of humans (neither imprinted
- Birds must be of an appropriate weight for the age, sex, and time of year for the
- Detailed care records noting the weight, feeding/food intake, fitness and
behaviour of the bird are extremely helpful for assessment of release suitability.
- 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
- Birds which have been in care for a short time should be released where they were found
or at the nearest safe point to their site of origin. (D27)
- The release site must provide habitat meeting the nutritional, biological and
behavioural needs of the bird being released and must be in the known distribution of the
- Appropriate prey must be available
- The habitat/terrain must be appropriate for the hunting technique of the species.
- Birds should not be released into a territory containing residents of the same species;
- This may not be possible for the commoner species.
- The relevant landowners and managers must agree to the release on their land and be
- Releasing birds repeatedly from one location should be avoided because
local suitable territories are likely to become saturated.
- Corvid populations in the area, which may mob any released bird of prey, must be
- The different habitat requirements of some species at different time of year must be
Timing of release:
- Release in fine weather.
- Release during the day (diurnal birds) or at dusk (owls).
- Release in winter (poor food availability) or spring/breeding season (intense
territoriality in wild birds) is probably inappropriate (except for birds
which have only been in captivity for a short time) as competition for territory is great
and all local territories will already be occupied.(J3.106.w3,
- Migratory species must be released during the period when that species is normally
present in the UK.
Type of release:
- This is most suitable for adults which have been in care for a short period of time.
- Release takes place back at the point of origin.
- A variety of soft release techniques have been developed for use with birds of prey:
- Traditional "hacking back", a process using falconry
techniques which allows the bird to develop hunting skills while food continues to be
provided, may be most appropriate for the release of hand-reared birds.
- This is best used for a brood or group of birds which have not yet
started to branch or fledge.
- It is less successful for a single bird.
- If the chicks have already started to branch or fledge they may leave
before associating the hack site with food and starve before learning to hunt.
- The chicks are placed in an artificial nest site similar to sites used in
the wild by their species.
- Food is provided daily by means of e.g. a chute or pipe which prevents
the birds associating the food with the human carer; food is ideally deposited at night
for diurnal species and in the day for nocturnal species.
- The birds fledge at the hack site and start exploring the surrounding
area at increasing distances.
- Once the birds have been flying for two weeks the food provided may be
reduced to encourage them to hunt.
- Food must be provided over an extended period following release.
- For barn owls, chicks are placed in a suitable nest box in an appropriate
building at 4-6 weeks old and fed each night.(D55)
- Chicks are likely to start fledging 3-5 weeks later but return to the box
as this is where food is provided.
- Food provision should continue until it is no longer taken; it is
suggested that food provided should not be reduced until the chicks stop eating all that
is provided. (D55)
- Provision of food initially may also be appropriate for adults which have
undergone a prolonged rehabilitation process and are being released away from their
original territory. (P19.1.w12, D24,
- Aviary hack:
- Most suitable for birds which are too old for traditional hacking back and for
scavengers such as kites and buzzards.
- A suitable aviary is erected at the release site and the bird kept in
this for a period prior to release.
- The aviary should have a good view over the surrounding area, and an area
of seclusion as a refuge if the bird(s) is/are frightened.
- One side of the aviary is solid; the carer approaches from this side and
leaves food via a hatch or pipe.
- After 4-6 weeks one side of the aviary or part or all of the roof is
opened (preferably remotely using a long line) quietly to allow the birds to fly out.
- This must be done carefully to avoid frightening the birds.
- Food may be reduced at the period just prior to release. The subsequent
provision of food will then encourage them to stay at the release site.
- Food is provided daily in or on top of the aviary, with a reduction in
food after two weeks to encourage hunting/searching for carrion.
- Suitable for the release of owls.(B203)
- Suitable for the release of kestrels.(B203)
- Hack board:
- May be used for one or several birds at a time.
- Birds may be trained to take food from an elevated board at a particular
- Falconry techniques are used to train the bird to fly to the board for
food, initially only a distance of about two metres, but increasing to about 50 metres, on
a line. The food is tied to the board so the bird has to remain on the board to eat.
- Daily flying to the board is continued until the bird's behaviour
indicates it is comfortable in the area.
- Prior to release the bird is taught to find food hidden under a
three-sided shelter on the hackboard (less vulnerable to scavengers such as corvids).
- The bird is then released but food provided daily, hidden in the shelter
and no longer tied down.
- After a few weeks the amount of food provided is reduced to encourage the
bird(s) to hunt.
- Lure hack:
- This is most useful for mature birds with hunting experience but which have suffered
major physical trauma or for other reasons need to build up muscle.
- The bird is taught to fly to the lure and is then flown to the lure daily to build up
- The bird is released from the site at which the daily flights have taken place and the
carer returns and offers food by calling with the lure daily.
- Calling with the lure should be continued for at least two weeks even if the bird is not
- Kite hack:
- The bird to be released is taught to fly to a kite to which food is attached by a
special device such that the food is released when the bird strikes at it.
- The kite is flown higher each day to reach several hundred feet (check on
restrictions on height of kite flying to ensure the kite does not interfere with aviation
- The bird is then released in the area in which it has been flown and the kite is put up
- Full falconry hack:
- Not suitable for some species.
- Involves full falconry training and hunting the bird by flying it at natural quarry.
- This allows the carer to fully assess the bird's fitness and hunting ability and the
bird to become familiar with the territory in which it is flown.
- The bird is released, once it is taking quarry regularly, where it has been flown.
- "Long release" of barn owls (Tyto
alba - Barn owl):
- This involves introducing a pair of captive-bred, unrelated barn owls into a suitable
building with appropriate surrounding habitat.
- The birds are confined to the building (but preferably have views onto the surrounding
area) for up to six months.
- Food is provided every night on a rat-proof table.
- Once the owls breed and the chicks are half grown the adults are allowed access to the
outside world, with the opening first unblocked at dusk.
- Food is provided as before and the amount eaten is used as one method of monitoring,
along with e.g. inspection of regurgitated pellets to see if the owls have been eating
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