Oustanding rescue of the giant sable antelope !!

04 September 2009 | News story

Rescue of the giant sable antelope (Hippotragus niger variani) in Cangandala NP, Angola - Contributed by Pedro Vaz Pinto

Background

When the rediscovery of the giant sable antelope in Cangandala NP, supported by trap camera photographs, was announced in 2005, few people could predict the frustration and uncertainty than soon followed. As the photographic record expanded and began to be critically analyzed, a shocking and unexpected reality became evident: the last surviving sable herd in Cangandala lacked a breeding bull and cows were producing hybrid calves with a roan antelope bull.
Over the last three years we witnessed the helpless decline of this breeding group, as three young sable males were pushed away by the roan bull, and the ageing females continued to produce hybrid calves. Since 2005, no pure sable offspring was recorded, and we found the remains of one sable female – presumably due to old age. In the meantime, a hybrid calf had been born approximately every six months, and ironically roan numbers had increased and threatened to replace the last sable group in Cangandala. The hybrids seem to be unfertile as no female hybrids have been recorded with calves.
In 2008, we failed to complete a planned capture operation because of the last minute cancellation by the contracted Namibian capture operator. By early 2009 the situation was totally desperate, and this population without intervention, was doomed to extinction. We had no sable bull in the park, and we were down to less than ten old cows, and similar number of hybrids, including two hybrid bulls. The territorial roan bull was still present in the area occupied by the cows.

The Luando Strict Reserve is the only other protected area where the giant sable is known to occur. Being more than 10 times larger (828,000 ha versus 63,000 of Cangandala) and with prime miombo mosaic habitat, it has long been the stronghold for this subspecies and assumed to be the reservoir from which animals could be found to repopulate Cangandala if necessary. However, the results from camera traps installed in the reserve over the last two years, gave disappointing results. The trap cameras often recorded roan, but no sable, while poaching in the area seemed to be out of control. By mid-2009 we had identified a few promising areas for sable, but we had still failed to localize a sable herd, less alone bulls.

 
Tackling the crisis

An emergency plan for 2009 was devised in consultation with Dr. Richard Estes, Dr Jeremy Anderson and Dr. Peter Morkel. Implementing this plan was considered to be the last chance to save the giant sable in Cangandala NP, and it was presented to and endorsed by the Angolan Government. We started off by building a 400 ha fenced sanctuary in the park, covering a relatively good diversity of habitats and including a drainage line. A capture operation was to follow and the objective was ambitious: first to capture and relocate as many of the pure cows as possible into the sanctuary, thus separating them from the hybrids and roan bull; secondly to capture and introduce a sable bull from Luando. The concerns were that no giant sable had ever been darted before, and an adult bull hadn’t been recorded in decades!

Just a week before we started the capture operation we obtained lab results on mtDNA from Oporto University in Portugal, establishing that one particular dung sample we had collected in June in Luando reserve was, as we suspected, Hippotragus niger variani.

The capture operation took place between July 24th and August 17th, and crucial to the operation was the participation of Barney O’Hara from Botswana with his well-equipped Hughes 500 helicopter and the highly experienced veterinarian, Dr Peter Morkel. This proved to be a winning team from the start.

The animals were to be darted from the air and, when necessary, also air-lifted suspended by their legs 33m below the helicopter. A temporary holding pen using opaque game capture plastic was built inside the sanctuary.

We also acquired several VHF and a couple of GPS/GSM sable collars from AWT.

All the activities were supervised by the Ministry of Environment, as leading Governmental agency in charge of Angolan protected areas, and the official representative on the ground was Cardoso Bebeca as Park Administrator of Cangandala NP.
 

The capture

On the first flight in Cangandala, we located the solitary roan bull and the sable/hybrid group totaling 17 animals, and a hybrid female was darted and collared. Subsequently she would be used to lead us to the herd and pure cows. She proved to be a very cooperative and trustworthy “Judas”, and over the following weeks we managed to catch all the nine pure cows in Cangandala, and transport them successfully to the holding pen.

The females were in excellent physical condition and were all at least relatively old, yet not showing excessive wear of their incisors. Their ages were estimated to range between 8 and 14 years. None of this was a surprise, since the first hybrids had been born in 2002. Finding all the females together and in good condition well into the dry season, was also consistent with reduced breeding opportunities, and only one of the females showed signs of lactation and having produced a calf (a hybrid) earlier in the season.

Once all the pure females had been relocated, we darted and collared a second hybrid female, but failed to find the remaining hybrids or the roan bull. By then, too much disturbance had been done, as the herd without the older females had lost cohesion, and the other hybrids had scattered.

While this was happening in Cangandala, we were also flying on approximately alternate days to Luando reserve, where the results also exceeded our expectations. The prime area was deep into the reserve but on our first flight we spotted and darted a giant sable bull, and the tone was set for the days that followed. In twelve days of flight over the reserve we darted 8 bulls and one cow. One of the bulls was collared and subsequently relocated to Cangandala. Because it was more than 100km away, the bull was transported to Cangandala inside a military Russian chopper MI-8 from the Angolan Air Force.

In total we saw 15 bulls in Luando, but only three females, with two yearlings and two small calves. The reason for this disparity may be due to the season, as the females were calving and more restricted in their movements, while males tended to be isolated and often their black figure were conspicuous under the leafless miombo. Sure enough, the one female had just calved recently when we caught her, and when seen a couple of weeks later, she had joined with a couple other females, two calves and a couple yearlings, plus one bull.
 

Conclusions

The success of this operation means that we can finally get a grip on this magnificent creature’s fate. If we are able to secure the area and manage the sanctuary properly, and if the animals adjust as expected, we may well have rescued the Cangandala giant sable population from the ashes. We have now one pure bull with nine old females, some who haven’t bred at least in years, and some who may have done it once and a while with the wrong species. How this bizarre historical breeding pattern would affect them in the future is uncertain, but first indications are very hopeful. From the first moment, the females accepted and submitted to the giant sable bull, and they have been following him everywhere since. The timing may also work well in our favor, as the bull is expected to induce estrus in the females during September. If everything goes as expected in Cangandala, we should welcome the first pure giant sable offspring in May 2010.

In the meantime, the sanctuary must be strengthened and greatly expanded, as management requirements are expected to increase substantially. In a couple of years time, the introduction of new blood from Luando will also be necessary.

In Luando reserve we were fortunate to have located an apparently healthy breeding nucleus that may comprise up to two giant sable herds, but we flew over large areas with little game and where sable seem to have disappeared. Human encroachment inside the reserve is obvious and poaching is a huge problem, as we saw several active bushmeat camps. An extensive census must be a priority, to define the best strategy and allow us to focus immediately on the most important areas. The hunting of bushmeat in the areas occupied by giant sable must be stopped as soon as possible.

The Angolan authorities are now called upon to conserve the national symbol, and the military are already active in Luando to provide security. While the future of this remarkable antelope is still uncertain, we may have now established a sound base for its recovery.

The Giant Sable Conservation Project is an initiative led by the Angolan Ministry of Environment in partnership with The Research Centre of The Catholic University of Angola and the Provincial Government of Malanje.