Feeding Raptors

Feeding Raptors
Jan 11, 2012 by Admin Falconers.com

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
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.

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.
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.