by Michel Saint Jalme Pictures by Xavier Eichaker |
During recent decades populations of houbara are believed to have declined drastically throughout the entire distribution range. Over-hunting and severe habitat degradation appear to be the main causes of the decline. While the species has been able to survive a long tradition of falconry in Saudi Arabia, the widespread availability of modern fire-arms and four-wheel-drive vehicles has made even the most remote populations vulnerable to hunting, and contributed significantly to the alarming decline over the last twenty years. Overgrazing of the fragile desert flora by domestic livestock has also caused massive loss of habitat for houbara. Of all the bustard species, the houbara is the one most adapted to the desert environment. Separated in three subspecies, the houbara of the genus Chlamydotis is distributed over a wide range. The nominate subspecies Chlamydotis undulata undulata inhabits the north African range. Chlamydotis u. fuertanturae occurs only on the Canary Islands and Chlamydotis u. macqueenii, of interest to Saudi Arabia, ranges from Sinai to western Mongolia. The houbara is thought to be resident in North Africa and the Canary Islands whilst the populations breeding in central Asia are migratory, wintering from Pakistan to Arabia where they overlap with the local breeding populations. The official IUCN category for the houbara is Vulnerable, which includes populations that are seriously depleted, or decreasing due to over-exploitation or other factors, and which are at risk of becoming Endangered if causal factors continue unchecked. The great cultural value of houbara in Saudi Arabia, and concern about the possible extinction of local populations, prompted the National Commission for Wildlife Conservation and Development (NCWCD) to take conservation measures. These include the identification of suitable habitat, habitat protection, studies of free-ranging populations, the foundation of a captive breeding population, and studies on feasibility of eventual reintroduction and restocking. In 1986 Harrat Al Harrah Protected Area was established around the last known houbara breeding area in Saudi Arabia. This reserve (12,000 km2) of sand, wadis and black basaltic rocks, is located in the northwestern part of Saudi Arabia, near the border with Jordan. Hunting is forbidden and grazing livestock is restricted to camels. In 1989 a second protected area was established at Mahazat As Said and the entire 2200 km2 area was fenced to assure complete protection against hunting and grazing. In Harrat Al Harrah, between 1987 and 1991 searches for evidence of breeding were undertaken. The population was found to be small and patchily distributed, and only six houbara breeding attempts were recorded in the reserve between March 1987 and July 1990. Two researchers of the NWRC, P.Seddon and Y. van Heezik began field studies at Al Harrah in November 1991, focussing on habitat utilization and documentation of seasonal changes in houbara density. The identification of specific habitats utilized by houbara may assist in the location of suitable areas for protection, and possible new release sites for reintroduction of captive-reared dirds. Surveys showed seasonal changes in the numbers of houbara. The population of houbara resident in the reserve in spring is probably less than 100 birds and only eight breeding attempts were recorded in 1992. Given that Harrat Al Harrah was set aside as the possibly the last breeding location of houbara in Saudi Arabia, these figures are very low indeed. Several questions remain to be answered: where do the houbara that over-winter in Saudi Arabia come from, and is there a clear distinction between resident and migratory populations? To answer these questions satellite and conventional radio tracking studies are planned, but progress depends upon the ability of biologists to trap these cryptic and wary birds. A captive breeding programme based at the National Wildlife Research Centre in Taif, managed by P.Paillat and P. Gaucher , began in 1986, utilizing breeding stock from Baluchistan and Algeria. As the species is known to lay a replacement clutch, authorization was obtained from the two governments concerned to collect eggs from breeding populations at the beginning of the reproductive season in order to minimize possible detrimental impact on the wild populations. One hundred and three chicks of the Asian subspecies Chlamydotis undulata macqueenii and 129 chicks of the African subspecies Chlamydotis undulata undulata contributed to the breeding stock. At the beginning of the project very little was known about the reproductive biology of the species. In North Africa eggs are usually laid between February and May but, occasionally, eggs were found in Algeria as early as November or as late as June. In Syria one can find eggs between March and May and in southern Russia between April and June. Some authors believe that rainfall is an important trigger for breeding and that this does not occur in dry years. It was believed that sexual maturity was achieved at two years old and the houbara was known to lay a single clutch of one to four eggs. Our captive brood-stock provided an opportunity to take a closer examination of the houbara's breeding biology. One of the first results was that when plentiful food was available throughout the year, the birds showed a seasonal breeding pattern with the laying period extending from January to July. We developed the hypothesis that an endogenous rhythm may have evolved to regulate the annual reproductive cycle. Synchronising factors are most likely to be seasonal temperature changes with rainfall acting as a secondary factor, perhaps leading to a lengthening of the reproductive period and thus allowing second clutches to be laid. Although captive, well-fed houbara are able to lay from one year old (6% of females), most undergo delay of maturity until they reach three or even four years old. As one might expect, older birds tend to lay more eggs. Records derived from egg removals and stimulation of replacement clutches showed that the mean number of eggs laid by C.u. macqueenii ranged from 1.7 for one year old birds to 11.8 for those older than 3 years. Nevertheless there is considerable variability in clutch size within each age class with the maximum eggs laid by one female in a single breeding season being 30 for C.u.macqueenii compared with 20 for C.u.undulata. Reproductive parameters for these two subspecies are rather similar although macqueenii generally displays greater reproductive capacity; larger clutch size and smaller inter-clutch intervals. Several natural management techniques were tested during the course of developing a successful breeding strategy: isolated pairs; heterosexual groups of various sizes and selective access to the male via doors allowing only female passage. The search for an optimal system continues since all of these methods yielded relatively poor results with only 20% to 50% of the eggs being fertile. Problems with natural breeding techniques led to the adoption of artificial insemination. Sperm are collected using a dummy female presented to a displaying male. When the unsuspecting male attempts to copulate with the model-female, the manipulator collects the sperm. Immediately after collection sperm is diluted and analyzed for concentration and motility and then inseminated directly into the entrance of the vagina of a receptive female. By improving the insemination techniques the level of fertility increased from 50% in 1989 to 85% in 1993. The release programme of the Asian subspecies, macqueenii, began in 1992, under direction of Olivier Combreau. Since the programme is still in its early stages relatively few results are available. For re-introductions to be successful the actual release techniques are a vital element in the programme. Even in suitable habitats, captive bred birds may experience difficulties in adapting to their new environmental conditions. Difficulties they encounter include locating food, spatial orientation, avoidance of predators, and resistance to infection. Both age and composition within social groups are also factors that have a bearing on the ability of released birds to survive in the wild. In order to examine these aspects in more detail release experiments were conducted in a 4 km2 mammal predator-proof pre-release enclosure situated within the much larger 2200 km2 fenced and protected area of the Mahazat As Said reserve. Pre-release cages were located within alfalfa plots in the protected compound. Different techniques were then tested with birds from one month to several years old, all of which were subsequently tracked through solar powered radio-transmitters with which they had been fitted. Trackers following the birds from ground vehicles and light aircraft gather information concerning their survival, dispersion, habitat utilization and social behaviour. An earlier attempt at such a release programme, conducted in 1991, failed when, within five days of their release, all of the captive reared houbara were eaten by foxes. In 1992 coveys of two chicks and a foster mother held for fifteen days in the cages and then set free within the pre-release protected enclosure, also gave disappointing results. The coveys showed a very high dependence upon supplementary food and the hoped for apprenticeship in wild feeding techniques, natural food selection, habitat utilization and predator avoidance by the adult females did not live up to expectations. On the other hand, sub-adult release, using birds of around one and a half months old which were translocated from the breeding unit to the pre-release cages gave somewhat better results. Out of 31 sub-adults thus released, approximately 50% were still alive inside the reserve six to ten months after their release. It is too early to draw any conclusions about the release experiments but the results obtained so far with sub-adults are certainly the most encouraging. In the forthcoming breeding season we shall be trying a variety of chick-rearing techniques aimed at enhancing the birds' ability to survive later in the wild. In September 1993 an international workshop was organized by the NCWCD in Saudi Arabia with the aim of reviewing progress and mapping future directions of the houbara programme. Workshop participants drafted recommendations that have formed a basis for a conservation strategy. The recommendations include measures to improve houbara habitat in Saudi Arabia, maintenance of a captive breeding programme, development of techniques for captive rearing and release of captive bred birds, promotion of public awareness and fostering of public support for houbara conservation and, finally, taking a lead in initiating cooperative conservation efforts between houbara range states. Captive propagation of the houbara has proven to be a difficult task. After a disheartening year of infertile eggs, the first breeding success was achieved in 1989 with the reproduction of 17 chicks. Fifty-five chicks were produced in 1990, 49 in 1991, 138 in 1992 from 60 laying females, and a record 283 chicks in 1993 from 75 laying females, allowing the release experiments to begin in earnest. |
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