5 Granite St.
Peterborough, NH 03458
18 February 2011
TO WHOM IT MAY CONCERN
I have read the Hirola Task Force’s proposal and find it very complete and well-reasoned in every respect. The plan for in-situ breeding of the hirola in a fenced sanctuary inside the Ishaqbini Community Conservatory is surely the best of all proposed alternatives for arresting the decline in this critically endangered species’ population.
I find the section on the Founder Population/Background confusing. All the other Alcelaphini (and virtually all antelopes in the Antilopinae), have a territorial social organization. Unless the hirola is different, only territorial males with females on their property are entitled to herd “family groups”, i.e. herds of females and young. That said, nursery herds of topi and hartebeest can remain semi-permanently on specific territories where territories are large and the habitat combines bushed and open grassland. Such is the case with topi in the Serengeti woodland zone near Seronera (author’s unpublished observations; see also topi and hartebeest accounts in Estes 1991). It is also possible, where an antelope lives at such low density that no territorial network exists, males will accompany female herds over a wide area (see roan account in Estes 1991). Assuming that hirola social organization is normal, one would expect the proposed sanctuary to be divided up among mature males in a territorial mosaic. Prime males would occupy the best habitat, as defined by female home ranges; old males would occupy suboptimal territories on the periphery, as do hartebeest in Nairobi NP (see account).
It is also unclear whether hirola reproduction in its natural range is seasonal or perennial. It is noteworthy that topi in eastern Kenya north of the Tana River are perennial breeders, though strictly seasonal in most of their range, calving at the beginning of the rains (Duncan 1975, cited in Estes 1991). This may be an adaptation to the irregularity of rainfall in the Nyika and coastal savanna mosaic. The same applies to sable (Hippotragus niger roosevelti) of the region (see account in Estes 1991). Of course, hartebeest reproduction is naturally perennial, at least in East Africa (see account). The question of seasonality is relevant to “harvesting” of hirola bred in the sanctuary. If the pattern follows the hartebeest system, then offspring will stay in the maternal herd, even to the sub-adult stage in the case of males. If seasonal, there will be a peer group of yearling females that can be released into the conservancy together. Similarly, there should be bachelor herds of sub-adult and young-adult males.
In-situ breeding inside a secure sanctuary and restocking of the Ishaqbini Conservancy are essential first steps in saving the hirola from extinction. Long-term, the success of the hirola in-situ breeding program will depend on whether a substantial portion of its historic range can be repopulated and protected.
The Kenya population, estimated at 16,000 animals in the late 1970s, ranged an area of ca. 17,900 sq km. The natural range of the Somalia population, of unknown numbers and now considered extinct, was about 20,500 sq km (Butynski 2000). “Today”, as the proposal notes, “Beatragus . . . exists only in the Ijara and Garissa Districts of Kenya’s North Eastern Province, between the Tana River and the Kenya–Somalia border. . . an area no more than 1,500 sq km.” The authors of the proposal promise that, “Continued survey work to identify the extent, distribution and status of hirola outside of Ishaqbini will be on-going.” Saving some substantial part of the hirola’s Kenya range from human overpopulation and habitat degradation promises to be the greatest challenge.
Submitted by R. D. Estes, PhD
Antelope Specialist Group chairman
Butynski, T. 2000. Taxonomy and distribution of the hirola antelope. Antelope Specialist Group Gnusletter 19(2):11-17
Estes, R. D. 1991. The Behavior Guide to African Mammals. University of California Press, Los Angeles and London.