Monday, August 22, 2011

Investigations continue

Investigations are continuing in the Makgadikgadi area to find the poisoner who killed three globally threatened White-backed Vultures on 9th August, 2011, and likely a Brown Hyaena too (as it dragged off the carcase to its den - see post below on 12/8/11).

Colleagues from the Department of Wildlife and National Parks are following up this and another poisoning incident which took place near Tonota in Central District earlier this month. Obert Gwapela, Park Manager for Makgadikgadi, is still trying to find the perpetrator(s) of the Makgadikgadi incident, and is working on several leads at present. Steven Sekhute, District Wildlife Co-ordinator based in Francistown, despatched one of his officers to the scene of the Tonota incident, but since then the officer has been in the field attending to several cases of human-wildlife conflict, so no information is available yet on how many vultures were killed there.

It looks unlikely that there will be any arrests following the Tonota incident, but we are optimistic that the Makgadikgadi case will soon yield results. As mentioned in the previous blog, an arrest and conviction would go a long way to deterring would-be poisoners, so we will be watching the law take its course with a keen interest.

Thursday, August 18, 2011

Safari companies protect key bird breeding sites

Two of the largest 'heronries' (or 'storkeries' or 'darteries' or 'cormoranteries', whichever you prefer!) in the Okavango Delta are in private concessions, and have been flourishing and attracting ever more breeding birds in recent years.
A pair of Marabou Storks, in nuptial finery, make a plan on their nest.

Lediba la Dinonyane (lagoon of the birds) is the largest and supports a great diversity of waterbird species. It is near Kanana Camp, run by Ker and Downey Safaris, and guides visiting the site always take care not to disturb the birds by approaching them too closely.
The same applies at the heronry at JereJere Lagoon, where there has been an influx of birds due to suitable conditions prevailing here. This heronry is near Xugana Lodge run by Desert and Delta Safaris, and this company is the custodian for this site.

The traditionally spectacular heronries in Moremi Game Reserve, at Xakanaxa and Gadikwe have been diminishing over the past few years, and most of the birds seem to have moved to Lediba la Dinonyane and JereJere. These two sites are well worth a visit as they offer the best of Botswana birding.

Friday, August 12, 2011

One step away from a catastrophe

Crescent Pan is a beautiful freshwater pan in the eastern Makgadikgadi, used by zebras and Wattled Cranes during summer, and by livestock and a variety of birds which come to drink and bathe during winter. On the 9th of August, guides from nearby Jack's Camp counted over 150 White-backed Vultures and 10 Lappet-faced Vultures drinking and loafing around the waterhole - an idyllic scene.

However, they soon noticed that something was amiss - there were three dead vultures among the throng. When they went closer to investigate, they found that the other vultures were all exceptionally lethargic and did not move away - they were sick and apparently dying too.

Fortunately the grapevine works fast, and the BirdLife office in Maun was able to notify Obert Gwapela, Park Manager for Makgadikgadi and Nxai Pan, and he quickly despatched Dr Kebonang Kebonang (DWNP Vet) to the scene.

When the DWNP contingent arrived, many of the sick vultures had recovered and flew off. One of the dead vultures, on examination, was found to have the crop and throat neatly removed, as shown in the photograph below - the rest of the bird was intact.

The dead vulture with crop removed (Photo: John Barclay)

This is most peculiar: the first reaction on hearing of vultures dying at a waterhole is that they have been poisoned with an organophosphate poison since this makes them very thirsty and they go to water where they die - in order to test for the presence of this poison, the best sample to take is the crop with the poisoned meat in it, but here the crop had been removed? This was looking increasingly like another poisoning incident, and perpetrated by someone who knew how to remove some of the evidence!

This led the investigating team to strongly suspect foul play, and a search was initiated for a poisoned carcase in the area. The presence of about 40 Marabou Storks nearby led to a site where a few small remains of a cow carcase were found; unfortunately spoor and drag marks showed that a Brown Hyaena (another globally threatened animal) had dragged off the bulk of the carcase and it is highly likely that it, too, is now dead from the poison.

Miraculously, by late afternoon, most of the vultures had completely recovered - only three had ingested a fatal dose of the poison and died. This is a real wake-up call to the authorities and to all who are concerned about the poisoning of Botswana's wildlife: this could easily have been a major mortality of all 150 White-backed and 10 Lappet-faced vultures, as well as the 40 Marabou Storks and 15 to 20 Black-backed Jackals that were at the site. And this is the real danger of these poisoning incidents: a few cases involving large numbers of vultures, in the middle of the breeding season, could decimate these already globally threatened birds. Currently, the Makgadikgadi is the most important breeding area for Lappet-faced Vultures in Botswana (and probably in the whole of Africa) and if the 10 birds of this species present at the site had been killed, this would have seriously dented the regional population of these magnificent birds.

BirdLife Botswana would like to thank Super Sande from Jack's Camp for reporting the incident so quickly, and Nicky Bousfield and John Barclay from Uncharted Africa for relaying the information, and sending in photos of the incident. Our special thanks go to our colleagues in DWNP who treated the incident with the importance it deserves and who conducted a swift, professional investigation.

Dr Kebonang examines one of the dead vultures (Photo: John Barclay)

Of course, the investigation is not over; samples from the dead vultures are being analysed at the Veterinary Laboratory, and the perpetrator(s) are being tracked down. We urgently need an arrest and prosecution to send a clear message to wildlife poisoners in Botswana that this practice is not acceptable.

Thursday, August 4, 2011

Much fuss about nothing

In recent years, there has been much hue and cry about the spread of avian influenza by wild birds, fuelled in part by the related deaths of nearly 300 people. These deaths caused people to speculate that there could be a new pandemic in the human population, with the virus being spread rapidly by migratory birds which circumnavigate the globe annually. As always, rumours are fuelled by lack of factual information, and in Southern Africa in particular, there has been little information available on the Avian Influenza Virus and its prevalence in the region.

These fears have been shown to be unfounded by work done by Dr Graeme Cumming and colleagues working in Botswana, Mocambique, South Africa and Zimbabwe. They counted, captured and sampled birds at five sites in the four countries, one of which was Lake Ngami, and did not positively identify any highly pathogenic H5N1. They also found that the annual influx of Palaearctic migrants had no detectable influence on this situation i.e. the migrants did not bring the virus into Southern Africa as had been speculated.

Other avian influenza viruses were found at a low frequency in some waterbirds, especially dendrocygnid (whistling) ducks. The White-faced Duck (shown above) and the Fulvous Duck, both have an extensive range across Africa, and individuals from populations north of the equator may mix with Palaearctic duck species, such as the Garganey, that migrate annually to western Europe. However, these two species had no trace of the lethal H5N1 strain.

For more information, read the original paper (see reference below).

Reference: Cumming GS, Caron A, Abolnik C, Cattoli G, Bruinzeel LW, Burger CE, Cecchettin K, Chiweshe N, Mochotlhoane B, Mutumi GL and Ndlovu M. 2011. The Ecology of Influenza A Viruses in Wild Birds in Southern Africa. EcoHealth Journal.