/ REINTRODUCTION TECHNIQUES FOR REHABILITATED AND CAPTIVE BRED BIRDS OF PREY Walter C. Crawford. Jr. Executive Director Raptor Rehabilitation and Propagation Project Inc. Tyson Research Center P. O. Box 193 Eureka. Missouri 63025 The techniques used for the reintroduction and training of rehabilitated raptors are many. Many of these techniques work very efficiently. others don't work at all. The most successful techniques. that have been used by rehabi1itators are generally those that have been developed by falconers. These falconry methods. which basically involve the flying of raptors at game and then returning these birds back to the wild have been in practice for hundreds of years. These techniques work very efficiently; unfortunately. they require a tremendous amount of man hours per bird. The use of these traditional falconry methods is not specifically designed for use on any large scale of reintroduction effort. For programs that handle large numbers of birds every year. the actual reintroduction of every specimen back into the wild using these techniques would not be feasible. But for the special cases. such as endangered species or a bird of special interest that is to be reintroduced into the wild. the following paper will explain the techniques involved in this process. After this particular bird has undergone its rehabilitation and has been deemed physically able to be released by the veterinarian or the individual in charge of this particular aspect of your project. then the training should begin.
Assuming that this is a young bird or an eyass. it has had little or no hunting experience. The following techniques can be employed with a relative good success rate of return to the wild. The birds must first be equipped with jesses. Jesses have been developed through generations of falconers and at present. two types are widely used throughout the world. The traditional jess is simply one piece of leather fitted to the bird's leg. Expansion marks are cut at appropriate intervals to allow for a proper, comfortable and secure fit. Properly fitted traditional jesses will cause no irritation or injury to the bird's leg. Another ~ethod. and perhaps the most widely used today, is the almori jess. This consists of an anklet fitted comfortably around the bird's leg secured with a metal grommet. Through these grommets are placed the jesses and as the traditional jess. at the end of these are fitted a swivel. Through the other end of the swivel is placed the leash. These leashes must be treated periodically to make sure that they remain supple and thus do not cause any irritation to the bird's leg. A jess fitted too tight can result in a foot injury and/or actual breaking of the leg. A jess fitted too loose can result in the escape of a bird that is not properly trained and probably lead to the bird'e demise in the wild. Birds properly fitted with jesses soon adapt to them and allow them to be checked or changed without stress. Any bird that is kept on jesses on a perch must be carefully watched at all times. After installation of the jesses on the bird, it is ready to be introduced to the perch on which it will be kept. It may require some actual training for the bird to learn exactly where it is to sit on the perch and the - 2 -
length which the leash will allow it to move. Bird's that have never before been jessed are extremely nervous. The most efficient way to prevent leg injuries is to fit each leash and perch with a shock absorber. This will allow the bird to leave the perch. reach the end of the leash and be slowed gently and pulled to the ground without any sudden jerk and the possibility of breaking or injuring the leg. Once the bird is fitted with jesses and has become accustomed to the perch. the daily routine of manning can begin. This technique is primarily teaching the bird to sit on the gloved hand and remain so while being carried about by the trainer. This,can be accomplished in as little as six hours or may take as long as a week with some birds. It is a time consuming procedure but extremely important in flying these birds on game. Once the bird has become manned and accustomed to its perch and jesses. it should be fed only on the gloved hand. It is extremely important that the bird associates the gloved hand with food. The rapport between man and bird must be developed. animals. cannot be intimidated into response. Birds. unlike other The correct amount of food and the bird's understanding that it will only be fed when on the gloved hand will allow training to continue. As the bird becomes more and more accustomed to feeding off the gloved hand. you can stand further and further away from the perch. making the bird fly from the perch to the gloved hand to receive its food. Once this is done on a regular basis. the bird is then ready to be flown on a creance line. A creance line is actually a line attached to the swivel at the end of the bird's jess. This line will allow the bird to fly at a predetermined length from its perch to an individual holding food on the - 3 -
glove. It is extremely important that someone who has had experience with working these lines assist during the training period. A sudden jerk and/or too strong a pull from the operator of the creance line could cause injury to the bird's leg. Once the bird has learned to fly capably from the perch to the gloved hand, the time has come to actually begin the hunting process. Large open fields are the optimum areas in which to begin the hunting technique processes. There are many ways this can be done. Live game can be trapped from th~ surrounding woods or the bird can be started out on other domestically raised typ~s of animals~ In no case should domestic chickens be used for the training of a raptor for release. This will develop a bad habit that it may revert to once it is released. It is important that the bird relate the animals to its well being and to its food supply. ~ow these animals are released into the field. At first, you can use a creance line. This will allow the bird to make repeated attempts to capture the game found in this area. The actual hunting process takes many many months to develop in a raptor trained by its parents. So, we cannot expect these birds in captivity to learn any faster. As previously described, countless man hours will be spent during this training period. The bird must be exercised or it won't have adequate flying ability to catch game that will be released for it in the field. This is an extremely important reason for flying birds on a creance line. You must make sure that no obstacles are nearby that might tangle the line and thus, injure the bird. It takes a minimum of two people to perform this training technique. Once the bird has succeeded in catching the game on a - 4 -
creance line, it is then time to remove the line and fly the bird free. There are a number of methods that can be used to facilitate the bird's return to the fist. One is to blow a whistle at feeding time everyday when the bird is fed. The bird then becomes accustomed to associating its food with the whistle and will return to the gloved fist. This will be helpful when in the field because if it should miss its prey and fly up into a high tree, it can be recovered readily. Another method is just a vocal call to the bird from the falconer which will usually call it back to the fist for its food. Once the bird has flown free for quite a few,weeks or even months, and is able to catch wild prey on its own, then the final stage of release can be brought about. The bird should be banded with the U.S. Fish and Wildlife Service band; jesses, anklets and all types of falconry paraphernalia removed and then the bird is flown to game in the field. After it has made a kill, the falconer can get in his car and leave. The bird will revert back to its wild nature within the following seven to twelve days. Another method which is used by some individuals who handle large numbers of birds is the aviary method of introduction of live food. In this case, birds are placed in large flight cages in which live food is introduced. There, they can learn from older residents of the aviary, such as old crippled red-tails and/or other birds of the same species that are kept as residents to help train the younger birds. Some birds should always be kept as residents to help train the younger birds. Some birds should always be kept in the aviary who will kill live prey. Through their exposure of watching the older - 5 -
birds, the younger birds will soon learn to kill live prey on their own. There are many methods for designing an aviary of this type. You can construct a large type of aviary with a metal flange around the entire bottom to prevent the escape of the mice and rats that are enclosed. Another method that has been used successfully is the incorporation of a metal type pool into the chamber where live game is kept. Live food is then placed in this container. This will allow the birds to sit on the side of the container and if so desired, capture prey. It is extremely important when. introducing live prey to any young raptor that you are careful with exactly what kind of prey you offer. The introduction of large rats to young, inexperienced raptors can result in the birds being bitten which may cause foot injuries. It is best to start these young rapt~rs off with mice, guinea pigs, and/or Coturnix quail until their prey capturing techniques have been perfected. In this way, no injury will result to the bird during its training period. It is also important to remember that the number of prey items introduced into an aviary must also correspond with the number of raptors kept in the same aviary. Fighting can result when two birds grab for the same animal. If possible, it is best to introduce live food in perhaps more than one area of the aviary at the same time to prevent competitive fighting among the birds for the animals. It is extremely easy to evaluate damaged birds who have undergone rehabilitation and are holding their own in the aviary condition. It allows you to see the strength, the ability, and the aggressiveness - 6 -
which each bird displays. This is important when trying to determine the amount of time until they are released. By watching the birdls flight, grasping ability, its speed and agility will also be important factors in this evaluation. Once the bird has been evaluated and it has been determined that it is ready to be released, it should be taken out, banded and released as soon as possible. It is best in a crowded aviary condition to enter in the evening after dark and quietly pick out the bird you want to release, thus causing as little disturbance as possible to the other residents of the aviary. You must be very cautious when removing pirds for release to avoid any feather damage or any physical injury. It is very important to be cautious whenever entering an aviary with birds that are being trained for release back into the wild. Owls, eagles and hawks have been known to injure or attack people when they enter these aviaries. Another method of release, in addition to the aviary and the falconry methods, is termed hacking. The hacking method is simply setting up an artificial feeding station for the birds prior to their release. A technique used by our center is primarily teaching the birds to feed off a hack board which is nothing more than a board on which food can be tied down and are taught to eat from. This is placed in the aviary and works very well with young birds such as kestrels and some of the smaller species of buteos. By using this technique, the birds are allowed to feed off the hack board until they become totally dependent on the board for their food, which is supplied fresh twice a day. They can, thus, perfect their hunting skills while in the wild and still be able to have an adequate amount of food - 7 -
available to them if they so desire. Some birds leave the hacking area almost immediately while others may remain for as long as three months. Food is continuously provided until all birds from this vicinity learn to hunt on their own and no longer use the supply of food from the hack board. It is essential to place the hack board up on a post where ground dwelling predators cannot consume the food left for the raptors. Careful monitoring of a hack board is essential. The release of owls into the wild is a completely different procedure than that used for any other species of raptors. Owls, due to their nocturnal habits, have been able to adapt a little bit better to being released in the wild than their diurnal relatives. An owl's natural instinctive hunting abilities are such that they hunt by sight and sound at night. These birds are generally quite readily adapted to the wild after release from captivity. Once they have become proficient in killing prey in an aviary situation, the best procedure is to remove them to an area where they will have a suitable food supply and/or protection during their initiation into the wild; and/or allow them to actually leave the aviary on their own by leaving the door open; food should continue to be supplied should they so desire. By doing so, you have a semi-hacking type of situation. The last technique for reintroducing young into the wild is called fostering. In this particular technique, young birds are placed in an already successful nest of raptors of the same species. Chicks can be added safely to a nest as long as they are downies. Almost all species will readily accept a foster downy chick of their own kind, however, they may recognize foster chicks of other species - 8 -
as intruders and kill them. It is extremely important that you remember you cannot overload the foster nest. The placing of too many foster chicks in one nest will actually lead to the demise of the entire nest, whereas the placing of one chick in perhaps many different nests would be more suitable. The techniques of releasing rehabilitated raptora back to the wild, again, are quite numerous. The options are always open and there is always room for new and improved techniques. It would be up to the individual rehabilitator to decide exactly what techniques are best suited for his/her type of situation. - 9 -