Vuture count shows increase
Vuture count shows increase
Birdlife Kasane is monitoring the local vulture population as a key indicator of the health of the ecosystem
Vultures are globally threatened due to human interference as well as a lack of breeding success. One vulture may lay a single egg each year for two consecutive years and then stop for the next four years due to a range of factors. Vultures need protection now before it is too late.
The main reasons for the decline are habitat degradation, powerline electrocutions, and poisoning. Poachers poison carcasses so that vultures will not reveal their activities. Farmers also poison carrion and leave it in the field to reduce the numbers of livestock predators, but the poisoned meat often destroys non-target species such as birds of prey.
Five species of vulture occur in the Zambezi region; the White-headed Vulture, White-backed Vulture, Lappetfaced Vulture, Cape Vulture and the Hooded Vulture. It is important that more work is done in terms of vulture counts and surveys in known breeding sites to quantify the numbers of these birds.
Birdlife Kasane carries out an annual count of the birds and nests at the White-backed Vulture breeding colony in Lesoma Valley. The count was done in August this year and regular checks take place throughout the year. This year 101 active nests were counted in comparison to 92 in 2010. Individual birds totalled 224 vultures.
The increase this year indicates a recovery from poisoning by farmers in 2009. Poisoning of carcasses to kill problem predators is illegal and BirdLife Botswana, together with other organizations and government, aims to tighten legislation to bring this problem under control.
There are still some aspects to the counts that need to be addressed. Although the nests (active / inactive) are recorded together with visible chicks, it is difficult to know without a more intrusive approach, just what the breeding success and survival rate of the colony is. These issues are best addressed by extensive ringing of birds or some other means of individual identification, perhaps even telemetry.
Additional data recorded during counts includes other species of vulture seen, species of the nesting tree, its condition and the number of nests in a specific tree. GPS coordinates are taken at the base of all the nesting trees on the Botswana side of the border, and for the trees in Zimbabwe a GPS estimate using a distance finder is taken.
Vultures are an integral part of a healthy ecosystem, deserving of protection and monitoring to ensure their success and preservation.
Read more from past issues:
Counting heads at top eatery (ZT, December 2011)
Vulture Restaurants Attract International Clientele (ZT, June 2011)
Read more about the region in our destination guide:
Read more articles from this issue:
Zambezi Traveller (Issue 07, Dec 2011)