TRAILING THE SPOTTED ONE
de Silva Wijeyeratne, G. (2010). Trailing the Spotted One. November – December 2010. Pages 32-33. Volume 5, Issue 7. ISSN 1800-0746.
Two leopard cubs fend off an enraged mother buffalo, a sounder of wild pig and a crocodile to regain possession of a carcass. Also a comment on how GPS encoding will make it easier to establish the density of leopard’s in Yala.
The morning procession of safari, curved past the Uraniya Plain which sloped away into the Southern Indian Ocean. A tall line of sand dunes bordered by thorn scrub forest interspersed with tall Palu trees, interrupted what was otherwise an unbroken stretch of grassland and sea, leading to Antarctica. “Nothing to see here’ echoed one jeep after another as they anxiously scanned the plains for a sign of a leopard. There was a carcass or at least what seemed to be a bit of a leg, left over from one feasted upon in the night by the highly desired spotted one.
I spied a pair of Brahminy Kites and Large-billed Crows and an image of the ecology of dry lowlands took shape in my mind. The hunters hunt and the scavengers clean up, nothing is left to waste. ‘Ermm.. maybe we should pull over and photograph the scavengers” I suggested to my host Chitral Jayathilake of John Keells Hotels. Chitral was also hosting marine biologist Dr Charles Anderson of Blue Whale watching fame. I had been speaking to Charles about combining Blue Whales with Leopards since 2003. Since Charles was not due to arrive in the park until the next day, I felt I could take the foot off the pedal and indulge in a bit of dry zone ecology.
I sensed Chitral would rather press on with Spotted Fever. But he was too gracious a host to decline the suggestion and asked Ajith Kumara to pull over. Whilst I set up, Chitral borrowed my Swarovski 7 x 42 and scanned the line of trees. I had barely got the tripod up when he triumphantly announced he had found a leopard. Not to be out done, Ajit Kumara snatched the bins and after a quick scan of the trees announced that there were two.
Well, what a start. Two cubs whose age we estimated at around 12-15 months were on the Palu trees. Before long a sounder of Wild Pig, around sixteen in number came and pulled out the carcass from behind a pile of rocks. What we had thought was just a leg left over turned out to be a barely eaten buffalo calf, on which the unruly and ill tempered pigs feasted upon.
We returned in the evening and parked in view of the cubs along with a many other vehicles. News of another leopard drinking water just a short distance away took us there. We photographed what was possibly a sub-adult, or a very young female, perhaps barely three years old which had mothered the two cubs. We felt that the action would lie with the hungry cubs approaching the kill. We headed back followed in another vehicle by who had spent the last eight years producing wildlife documentaries with Tigress Productions in London.
What unfolded next was sheer drama. A crocodile was now scavenging on the carcass. The female cub, muck more plucky and aggressive than her male sibling, climbed down and confronted the crocodile. After much snarling and intimidation, she pulled the carcass away. But before the cubs could feed on it, the mother of the buffalo calf, accompanied by another female chased the female cub away. After a while she returned to the carcass. She was unlucky. The sounder of wild pig which had claimed possession of the carcass happened to saunter back. One broke into a trot and then into a run and faced off with the snarling cub.
Out numbered, the leopard cubs had to back off and the female broke into a run and headed for a small tree. A wild boar chased her and reared up on its hind legs attempting to gore her. After a while she jumped down and ascended to the safety of the canopy of the tall Palu trees. We knew that after such a confrontation the cubs would not risk descending with the pigs around and drove off to investigate the alarms calls of Spotted Deer. A few hundred meters away, a large male leopard crossed a clearing. Another vehicle pulled up and commented about the two leopards on the road. It then struck us that whilst we watched the male crossing the clearing, another two males were seated on the road in front of our vehicle.
Back in the office I measured the distance and found that on what was a 600m line of road, we had six leopards. The leopards in Yala are increasingly become unusually tolerant of each other at carcasses. Wildlife photographer Namal Kamalgoda had told me how on one occasion photographers had observed six leopards at the Palugas Wala waterhole where dead buffalos lay, victims of the seasonal drought.
I also knew that in this area was another adult mother with two sub-adult cubs, aged around 18-24 months as at July 2010. So potentially, there were at least 9 individuals leopards within a 2-3 km radius. Although some of the individuals we had seen may have crossed from their home ranges into where the carcass was.
Later I explained some of the leopard arithmetic to Dr Charles Anderson. The late Ravi Samarasinha had individually identified leopards using photographic identification over eight years. He had always insisted to me that in this area of the park, the average density was one leopard per square kilometer. This is probably not rivaled anywhere else in the world. The average density is not to be confused with home ranges. There is a general acceptance that the home range for an adult female is 2-4 square kilometers. Say, the average is 3 square kilometers. A female has on average two cubs. That would make 3 leopards in 3 square kilometers. That is one leopard per square kilometer. When you consider the dominant male whose home range of 16-20 square kilometers encompasses the ranges of a few adult females and transient leopards (sub adults in search of territories), it is not hard to see why Ravi’s claim is justified for certain areas of the park. Leopard numbers are in a sense artificially high as the waterholes in the park are man made and were used over a thousand years ago to water agricultural land which has now converted to wild grassland. The combination of water and grassland creates a super abundance of Spotted Deer which form a deep prey base supporting a large number of carnivorous leopards,
There are already many photographers sharing their leopard images on Facebook and Flickr. In a few years time, almost all digital images will be encoded with GPS data. It will not be difficult for an armchair leopard researcher to study these images and establish how many individual leopards are being seen in the leopard rich areas of Block 1 of Yala National park. We will then see whether the late Ravi Samarasinha and I are exaggerating our claims of the density of leopards in Yala or is Yala truly the world’s top site for leopard density.