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General Aims - To feed a diet as similar to
the consumers natural prey species that the bird would enjoy in the wild,
whilst at the same time ensuring the correct food quantity, quality,
wholesomeness and storage methods. As most keepers will appreciate, the feeding
of neonates, involves a whole set of different problems, so in order to keep
things simple, we will consider feeding adult birds only. PROBLEMS ENCOUNTERED WITH FEEDING ADULT BIRDS Source of Food - Irrespective of the food
type, it is obviously essential that one is as far as possible 100% certain
as to the quality, source, method of killing, freezing and storage of the
food. Any ex-wild source of food eg. pigeon, game,
etc. must be considered. We always have to ask the question, why did the
animal / bird get run over in the first place? Was it simply bad luck, or was
it unwell that day? Whatever the reason, it failed the test of life that day
and should be considered as being potentially unwholesome. Such birds can
carry bacterial infections such as Tuberculosis, Salmonella or virus
infections such as Paramyxovirus, Adenovirus or Rotavirus, or be contaminated
with a poison e.g. alphachloralose. Any wild sourced food should be in good
body condition, have been caught and killed by physical means, and on
examination of the carcass should look in all respects to be thoroughly
wholesome and free of disease. It is crucial that the abdomen of such birds
is always opened and the surface of the liver checked. If any small white
spots are present on or in the liver, (often indicative of avian
tuberculosis) the whole carcass must be rejected, Rifle shot, ferreted or trapped rabbit, pigeon or other should not be assumed to be free of pathogens or indeed lead. Recently Richard Jones, my falconer colleague, acquired some rifle 'head shot' rabbits for his Harris hawk. For interest we X-rayed these rabbits, prior to feeding. In each case, as the rifle shot had penetrated the |
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base of the skull, it had left a myriad of
lead fragments, any of which would have been plenty large enough to cause
disease and death of the bird. Ferreted or trapped rabbits are the cause of
lead poisoning cases every year. Often it is the time that a rabbit has been
'pricked' by some poor shot on a previous occasion, only to carry on running
around the countryside, with a few pieces of lead on board. We are not
suggesting not to feed such material, but simply to be aware of and quantity
the risks. Most importantly to be aware of the signs of lead poisoning, so
that if they arise, you get the bird to an experienced avian vet immediately
so that the situation can be saved. SIGNS OF LEAD POISONING - ANY NERVOUS SIGNS
WEAKNESS OF LEGS IN PARTICULAR OR WINGS. Any food such as rats, mice, squirrels or
foxes, are less likely to cause any infectious disease to your birds. The
reason for this is that most pathogens will only affect one family of
animals, i.e. a rodent virus is highly unlikely to affect birds. Conversely
feeding any avian derived foodstuff is a potential risk. In recent years we have encountered several
outbreaks, in particular of virus disease, (eg. Adenovirus and Rotavirus),
where perfectly healthy commercially sourced quail, day olds, turkey poults
etc., have been fed to healthy raptors which have then succumbed to disease
and in several cases died. The problem here is that many pathogens including
viruses can be harboured by one species (eg. day old chicks), without causing
it any harm, i.e. the chick looks and is healthy, but when the chick is
eaten, the raptor is infected. Sadly although the virus did not harm the
chick it may conversely be deadly Pigeons form a special risk to raptors on
account of their high incidence of Trichomonlasis (frounce). Many falconers
believe that if they only feed the breast there is no risk. Sadly this is not
true. |
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Stressed, old, young or ill birds will be most
susceptible. Birds in perfect health may avoid the infection, otherwise most
wild peregrines would suffer badly. However no risks should be taken, all
pigeon which is fed should be frozen completely and thawed before feeding.
The duration of freezing is unimportant. Rabbit - Just occasionally when feeding larger
species on rabbit or hare a problem can arise. If the bird is sufficiently
greedy it may take the whole thigh (femur) bone of the rabbit. On many
occasions the bird will cope with this, however sometimes it will wedge
sideways in the crop or proventriculus. This may cause a perforation of the
gut lining or an obstruction. The recommendation for such sized birds is to
break the femur before feeding the carcass if the bone is taken in two
sections no problem will arise Storage of Food - One has to accept that any
food will have a number of bacteria in it, Any delay which occurs between the
death of the food, and its freezing (or feeding), will allow that number of
bacteria to increase. Any excessive food storage (ie. freezing for more than
3 months), will lead to a deterioration in food quality, in particular the
vitamin content. Any delays between thawing the food and its ingestion by the
bird, will again allow the numbers of bacteria to increase. Whilst any bird
is designed to, and is capable of, safely eating food with a certain
bacterial load, if this load is excessive, the bird will not cope, and become
ill. Feeding the Bird which is low in
Condition - Many falconers have an obsession about giving
casting each and every day. As all keepers should be aware it is important
not to feed a bird again until it has brought up the casting from the
previous day. If you have a bird, which is low in condition, you do not want
to have to wait a full day before you give a further meal. In this situation
it is quite permissible, if not essential, that you do not give any casting. |
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Instead you give a small meal of finely
chopped meat, perhaps with a little added saline. As soon as, and not before,
the bird has put its crop over it should be given a further small meal. Sour Crop - 1 would hope that all falconers
would be aware of the condition of 'source crop'. If food has passed from the
crop into the proventriculus (stomach), stomach acids will act upon it,
aiding the digestion as well as preventing any bacterial action on the food.
If conversely the food stays in the crop, it is no longer in your fridge
being kept nice and cold. Instead it is at body temperature (40-41°C), and
yet has no acid acting on it to prevent bactehal decay. In short the food
goes off very rapidly, causing the production of toxins (poisons) which very
rapidly kill the bird. If your bird is slow to put its crop over, then a
small volume (0.5% of the bird's body weight, i.e. 5ml for a 1 Kg bird), of
saline should be given by mouth. This will usually quickly result in the crop
being put over. If it does not, and the bird does not through the crop back
of its own accord, then the food must be removed by milking it back up from
the crop. This can be a risky procedure, as any fluid present in the crop
will return as the meat is brought back up and the fluid may go down the
windpipe causing a fatal pneumonia. Whatever the outcome the bird will need
veterinary care and antibiotics. Sour Crop Prevention - There are certain times
when sour crop is particularly common. Any bird which is off colour,
stressed, underweight, cold, chilled or which has an over full crop is less
likely to put its crop over. In particular this often occurs when a bird is
first entered. The keeper has had to drop the weight, perhaps a little too
low for comfort, in order to encourage the bird to enter. Having made its
first kill, he is so chuffed he rewards her by letting her have a full crop.
However the bird being underweight is very hungry, the bird is pleased, so is
the falconer, so he lets her have a really good fill. The only trouble is,
all too often, too full. The |