Two conflict situations between raptors and farmers in southern Namibia.
In the first week of November 2008 a commercial sheep farmer in southern Namibia reported that a flock of about 40 vultures were harassing and killing livestock on a 9000 hectare farm divided into about 45 camps. The farmer was neither able to identify the actual species nor give the ages of the birds but from the report it is assumed that both Whitebacked and Lappetfaced Vultures were implicated. At the time of the report the birds had been on the farm for 10 to 14 days and that they were so intent on the feeding that only after making serious attempts to chase the birds and then firing at them did the birds realize the danger posed by the farmers’ approach.
Most fortunately for vulture conservation this farmer clearly did not want to kill the birds. Although he reported predation of lambs and attacks on adult ewes and that his losses were in the order of two animals per day. The farmer did admit that the livestock are not in very good condition, being the end of the dry winter season through which some ewes had carried lambs. This commercial farmer manages two farms, about 18 000 hectare with six employees.
Just two weeks later another bird lamb conflict was reported. This time a pair of Black Eagles were predating on sheep lambs and occasionally on springbok lambs. These birds were reported to be taking more than one lamb a day and only eating a little off each carcass. The nearest mountains are kilometres away, so suggesting to the farmer to move the flock from the eyrie view was of no value. The farm is 5000 hectare and with 800 sheep is grazed at 1 head per 6 hectares. The entire farm is electric fenced and no labor is employed for the sheep.
In southern Namibia
the carrying capacity of the land ranges from around 20 kg per hectare
or 1 small livestock unit per 2.5 to 3 hectare in the Kalahari Gochas
and Aranos areas, down to 15 kg per hectare or 1 small livestock unit
per 4 hecatre in the Stampriet and Kalkrand area. The carrying capacity
can be as low as 5,5 -7,5 kg per hectare or 1 animal per 6 to 7 hectare.
On the farm where the vultures were reported predating the carrying capacity
is at 1 small livestock unit per 5 hectares. This means that in the camps
of around 200 hectares carry about 40 sheep.
During the vulture breeding season food requirement for the population is at its highest. By November most breeding Whitebacked and Lappetfaced Vultures will have completed their 2 month incubation of eggs, their 4 – 5 month period of nestlings and be somewhere in the 6 month post fledging dependence period. Birds newly fledged will remain in the vicinity of the nests, older fledglings will start foraging with the adults. Large nestlings will be consuming maximum amounts in the last pre-fledging growth spurt and young fledged birds pre or just post dependence will be out in nursery groups. In southern Namibia these birds may be on the extensive commercial small-stock-predator-free farms.
The problem for vultures is that without any predators on the land there is little for scavenging birds to forage on. Natural deaths of domestic stock in a well managed flock will be limited by the attention to herd health through disease, parasite and grazing management and strategic marketing strategies. A farm maximizing the graze and browse for domestic livestock will not leave much for wild antelope and those populations will not be able to thrive. The problem for eagles might be that there are few small prey species because of extensive changes in the landscape from years of intensive grazing.
Ideas and methods
to solve the numerous conflict issues between humans, their livestock
and wildlife rely on cooperation and innovation from farmers. For the
issue of predation there is the possibility of traceable wildlife-friendly
lamb or sheep, of insurance of stock and of course there is always room
for improvement of the herd/livestock management as well as the veld management.
In the northern Cape innovative methods to deter eagles from predating
on lambs include the use of balchatri trapping and the use of electric
shock sheets. However both methods can be dangerous to the birds and therefore
require dedicated raptor conservators who can spend the necessary hours
that may be required for either technique to work.