Archive for March, 2008
One of the pitfalls to avoid with training sniffer dogs is that the dog mustn’t be following the handlers scent to the hidden scent article. We may not like the idea of it, but to our canine friends, we smell very strong and it is very easy for them to follow where we have been. I first held Snoopy in the palm of my hand when he was about 24 hours old, and he is very much my dog. For the first year of his life, it was just the two of us, and we formed a very strong bond. We now live in a far more social setting, with my husband, daughter and four other dogs, but our bond remains. He could find my scent anywhere. He has been doing very well with finding the scat samples, and in his first open field trial, he found all the samples as well as the containers that I had brought them in. In order to test that he is looking for the cheetah scats, and not looking for something with my scent on, I set him up with a trial where I placed two identical pots out, one containing a scat sample and one without. I then sent him into the area to search for the scent. In 11 out of 12 replications, he went straight to the pot containing the sample, and with the remaining one, he quickly ignored the empty pot and continued on to find the real sample without any further prompting from me. This is all the confirmation I need to show that he is indeed looking for the right scent. As our bush is very thick, I wanted Snoopy to work with a bell on his collar to help me keep tabs on him, but for some reason he absolutely hates it, and so as a compromise, he wears an alarmingly red collar which shows up well in the field. Barclay is a little slower off the marks, due almost in entirety to his age. At about 7 months old, he is still very much a puppy and has a very limited attention span at the moment. I am giving him space to grow up, learn about the bush, and learn some basic obedience. He is passionate about tortoises and finds them often on our walks, so I have no doubt that his nose works. His other big passion is Nightjars, a small nocturnal bird, that has a dog-enticing habit of flying off only a short distance when startled before resettling on the ground. His nose works, and his will to search is there, so I don’t doubt that he will grow up to be a great dog. For the next month or so though, he will be busy just being a puppy.
Two cool still nights provided perfect conditions for our call ups. Too much wind can disrupt the distance the call carries and in the past we have had to postpone our survey last minute because the wind was too high. The first site didn’t bode well for a productive night with no visual or vocal response, but spirits soon picked up at site number two where we were rewarded with two Spotted Hyaenas coming in. While they are more familiar to most people that their brown relatives, they seem to be more scarce here, and we certainly see them much less often. This may be due their being persecuted more heavily by farmers before the land was protected, due to their more predatory nature and due to the ease of locating them as a result of their vocalisations. It may be that they were more easy to wipe out by poisoning, which was commonly used in this area in the past, due their tendency to forage together. Brown Hyaenas are more likely to forage alone, and so a poisoning incident would maybe kill only one clan member than several. Happily, Brown Hyaenas seem to be doing very well here and all evidence points to the Spotted Hyaenas making a comeback. In total, we called in six Spotted Hyaenas, four Black-backed Jackals, four Lions and five Brown Hyaenas. Of the Brown Hyaenas, four came into one site at the same time, which is very unusual. As it was the first site of the night, just after dark, I suspect that we were calling near their den site and that they were all still nearby at the beginning of their evenings foraging. The site was near a dry riverbed, which is known to be a preferred choice for Brown Hyaena den sites. This week we will be taking our speakers up to Mapungubwe National Park to carry out our surveys there. Call-ups we have carried out there in the past have shown good numbers of Spotted Hyaenas, and there have been reports of more lions moving into the park, so we are very excited to see what comes in.
One of the ways of determining population density of some species of carnivore is to take advantage of their opportunistic nature and play calls of a distressed prey animal over loud speakers to attract them to the area. By working out how far the call can be heard, we can work out the area that is covered by the call, and so calculate the density of animals in the area. This must, of course, take into account that not all target animals will respond. Due to the differences in vegetation and topography, calibration onsite is essential, as the response distance here on Venetia may be quite different from in other places where the work has been carried out. Earlier this week, we tested this by sitting one vehicle with Tsotsi and Tsala, two lionesses at Venetia, and their cubs and another vehicle taking the call-up equipment (a public address system with loud speakers) to 5km away. In radio contact with the team sitting with the lions, Wendy and Azwafarwi moved closer until the lions pricked their ears up in the direction of the call. They responded at 3.5kms, and so this is the distance we use as the radius for locating our call-ups stations to ensure there is no overlap. To minimise the chance of counting the same animal twice, all the call-ups will be done as close together as possible. Watch this space to see what comes to the calls!
Just recently we had Dr Peter Brothers, a wildlife vet, on the reserve and so took the opportunity to change some of the collars that were approaching the end of their lives. Two male lions, Blade and Subipe, had their collars changed, along with one of the subordinate female wild dogs. We maximise the opportunity of having the lions and wild dogs under anaesthetic and take blood samples and check on the general condition of the animals. There has been an outbreak of suspected rabies in the area, so we took the precaution of vaccinating the wild dog pack. Due to their highly social nature, wild dogs are susceptible to infectious diseases and whole packs can be wiped out. There is another pack of wild dogs just over the border in Northern Tuli Game Reserve, Botswana, where some of the suspected cases of rabies have been reported, which has also been vaccinated against the disease. In order to anaesthetise the lions to allow us to change their collars, we need to approach them in a vehicle to a distance of about 20m, then a dart filled with the drug is shot from a specially designed air-gun into the rump of the animal. There is quite a skill in shooting the dart hard enough to be accurate, and softly enough not to have more of an impact than is necessary. The rump is the target as it is the biggest muscle mass with the least chance of hitting bone. After the dart has found its mark, we wait until we can see the lion has gone to sleep (then wait a little more just to be sure), and approach carefully from behind it to check it is fully out. The heart-rate is monitored, and the eyes covered for protection while the necessary work is carried out. On hot days such as we have been having recently, we spray water over the sleeping animal in order to prevent them from overheating. When everything is completed, an anti-dote to the anaesthetic is injected and we wait from the safety of our vehicles to see that the lion comes round and walks off. They usually look a little dazed and confused to begin with but are back to their normal selves very quickly. Darting of animals should only be carried out by skilled vets and so we offer our sincere thanks to Dr Peter Brothers for his help. |
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