Abstract
C aptive breeding is usually one of the last methods employed by conservation authorities but internationally it is increasingly used in the fight to save endangered species from extinction. Captivity is regarded by many as undesirable and some even advocating that a species should rather become extinct than be brought into captivity. Nothing brought this home to me more than a visit to the Californian Condor breeding centre managed by the San Diego Zoo. It was explained to me that the fortresslike appearance of the facility was to protect the birds from extremists who had threatened to kill the birds rather than allow them to be held captive.
Fortunately, however, there has in recent years been an ever-increasing number of success stories which have calmed the objections of the critics of captive breeding. Most recently I have just read that the American Peregrine Falcon, re-established from captivebred birds, has been removed from the threatened and endangered species lists in the USA.
Conservation authorities will most often use the option of translocation of individuals from an established, secure wild population to be used as founder members for a new population. When, however, the wild population is already at a low point and can not safely be harvested to provide sufficient individuals for translocations, captive breeding, which can be initialized with a handful of founder members, becomes an option.
Captive breeding is no longer the hit and miss affair it used to be and the goals of most captive programs are decided on by a recovery group. Captive programs are run - often with expert advice from a taxon advisory group (TAG) - in accordance with a
captive management plan, which is part of a species recovery plan and defines the goal of the captive program. The Reintroduction Specialist Group (RSG) is part of the Species Survival Commission (SSC), which is in tum part of The World Conservation Union (IUCN). The RSG have produced guidelines for re-introductions and publish a regular update on some of the re-introduction programs globally.
Single species holdings, high standards of record keeping, husbandry and hygiene, strict disease screening and management protocols, researched release methods, and good post release monitoring are now the accepted code of conduct for captive breeding/release programs.
Captive breeding involves a longterm commitment and is an expensive process. Release sites have to be carefully assessed and seldom is a single
release successful in re-establishing a population. Techniques and protocols are usually refined over a number of years and successive releases. Even once a reintroduced population is looking likely to establish, supplementation with captive-bred birds is often required to ensure long-term success.
Once the captive husbandry techniques have been successfully established and documented in a husbandry manual, the next step, and probably the most challenging is to find sufficient safe habitat and to develop successful release methods for the species concerned. Factors responsible for the initial decline of the species have to be addressed prior to releases. These factors vary significantly throughout the world but the most common factors responsible for species declines are human pressure and the resulting loss or fragmentation of habitat and the introduction of alien plant and animal pests.
Another common denominator when looking at endangered species on a global scale is the high percentage of island species, often endemic, which are in dire straits. New Zealand, for example, has lost about 500/o of its terrestrial species, Hawaii 15 out of approximately 50 species and Guam 10 out of 13 species.
Animal pests, which impact on the native species, vary greatly from feral cattle, goats and pigs to monkeys, mongoose, rodents, and mustelids (stoats, ferrets, and weasels), snakes and introduced birds. Some of these introduced species alter the habitat, others compete with native species for food and nests and some prey directly on eggs, nestlings and/or adult birds. The Pacific Rat is on record as being responsible for more species extinctions in the Southern Hemisphere than any other single species or factor.