Mac, an elephant tracked and monitored by Steve and Michelle Henley since 2002, is sharing his dating secrets with more than a million listeners across the globe. Since April 2008, Mac's movements are being broadcast every Tuesday by the BBC radio service. Mac's movements while he is in musth are part of a 40-part series, World on the Move. The series charts the movements of animals around the world as they migrate and disperse. Presenters Brett Westwood and Philippa Forester connect with scientists, conservationists and field workers around the world to get the latest news on a specially selected array of animals.
"We keep our audience in touch with animal journeys all round the planet over an entire year. Amongst other things we aim to reveal how environmental and ecological changes affect the animal journeys and their lives. We look at the relationship between people and animals along the journey routes and explore their cultural and practical importance," says Julian Hector, editor of the BBC's Natural History Unit, Radio.The radio show reaches around 867 000 listeners during its live show and 420 000 listeners with the repeat show on Wednesdays.
Ever since Michelle and Steve first collared Mac in 2002, he has made an annual trek from Shingwedzi in the Kruger National Park to the Associated Private Nature Reserves (APNR) when he comes into musth. "Mac gets his name from Tony McClellan, who first sponsored his satellite collar. The monthly service fee for Mac's collar has kindly been sponsored by the Lowveld Region of the Wildlife and Environment Society of South Africa (WESSA). He moves a distance of approximately 200km in 10 days from the north of Kruger to the south of the Timbavati Private Nature Reserve. Last year we were sorry to hear that he was found in very bad body condition with a serious foot injury. The Kruger National Park (KNP) kindly darted him and treated his wound. Because of his injury and bad body condition he skipped his annual musth cycle and never came down to the private reserves," says Michelle.
This year the Henleys were confident he would make his journey when he came into musth after finding his body condition had greatly improved since his injury. He was still in Kruger at the time of this observation. Mac usually comes into musth between mid-April and mid-May. This year he came into musth at the beginning of April, and "regrettably we missed part of his journey south because of his early musth cycle," says Michelle. The BBC asked the Henleys to track Mac's movement during his musth cycle and the KNP and APNR allowed the couple to track Mac day and night, starting on April 4, 2008.
Mac is also part of another research project conducted by Dr Andre Ganswindt and Stefanie Muenscher to investigate the physiological and hormonal triggers of musth. He is one of eight elephant bulls that were collared on the borders of Mozambique. These eight study animal's collars were provided by the Transboundary Elephant Research Programme. The Kruger National Park kindly fitted the collars. With these additional collars in place the Henleys hope to understand what drives elephant movements into peripheral conservation areas such as the Associated Private Nature Reserves to the west and Limpopo National Park to the east of Kruger.
On April 4, Andre notified Michelle that Mac was already showing signs of musth and the Henleys hastily stepped up their arrangements to track the big bull. With all the arrangements in place and recording and night vision equipment on loan from the BBC, they found Mac in a dense mopane veld in Kruger on April 10. "Although we were at times no more from 30 metres from him, we couldn't see him." They tracked him with the VHF transmitter embedded in his collar, heard him and could even smell him, but he stayed out of sight. The distinctive signs of musth, a Ďproud' posture, swollen temporal glands and dribbling urine were already distinct at the beginning of the month. "It was the distinctive smell of the dribbling urine that we were now picking up."
Another lone bull in musth might be why Mac began moving south the following day passing through relatively remote areas in Kruger. "Elephants are able to communicate for long distances (six kilometres or more) using low frequency sounds and the low rumble made by another musth bull about three kilometres away would almost certainly have been picked up by Mac." On the late afternoon of April 16, the Henleys caught up with Mac in time to determine he had crossed the Olifants River just before midnight and moved out of Kruger at about midday on April 17 when he moved into a dense woodland area in the APNR.
On April 17, the Henleys saw how "another, smaller bull, also in musth, stormed from the bush and gave chase. We followed them for about 300m into a dry river bed where Mac had stopped and turned to confront the younger bull. It was obvious even to us how the other bull slipped from a dominant to decidedly more uncertain disposition. They faced off for about 20 minutes in the river, Mac occasionally thrashing a shrub, the young bull shifting from foot to foot and slowly backing away. As the dynamic shifted in Mac's favour we decided that where we had stopped the Land Rover we effectively blocked an escape route of the younger bull, placing us in a vulnerable position. We started the vehicle to move forward, this broke the tension and the smaller bull bolted. Mac strode around the place he had been standing, clearly the dominant bull," says Steve.
The following day, Mac was in the central Timbavati Private Nature Reserve. His behaviour had changed, in line with him being in his home range. He deviated from his onward southward movement, inspecting places where there was evidence of other elephants. "He is probably scanning for cows that may be coming into oestrous in the near future and bulls that are potential competitors." On April 19, the Henleys scaled back on their observation with Mac, to catch up with the other elephants they track as part of their research project.
Two days later they noticed Mac had moved back into Kruger via the Timbavati River, having reached the southern borders of the APNR and further south than he had been in previous years. He once again entered the APNR where the Henleys observed a relatively large number of bulls in musth at the time. There were obvious changes in Mac's movement during the last week in April.
"He has started to criss-cross the full extent of his musth range. He is still moving relatively rapidly, compared with his typical foraging type movements, but his route now represents a more extensive search pattern, seeking out the breeding herds and other bulls." Much of the Henleys' time during the week had gone into the re-collaring of other elephants in their research project. They re-collared two bulls on Saturday, April 26.
"A number of the collars currently deployed are reaching the end of their lifespan and as we are studying long-lived individuals within a dynamic environment, we want to continue gathering data." South Africans, except the faithful international radio fans, can follow Mac's ongoing mission in musth on the BBC website at www.bbc.co.uk/radio4/worldonthemove.