Another trip to Khao Yai in the wet season. This time I stayed in Green Leaf for a week and made a number of trips to the park and surrounding bat caves. I also met a wildlife biologist from Western Australia – Tony Start. Tony did his PhD on bats in Malaysia, so we had a lot to talk about and have made some exploratory bat trips together.
Khao Yai was unusually quiet this time around, in terms of wildlife sightings. During the three trips to the park we saw the usual – White Handed Gibbons, plenty of Variable Squirrels, Barking and Sambar Deer and Pig-tailed Macaques.
Birds were also quiet this time. I did see plenty of Great Hornbills though and a flock of Oriental Pied Hornbills. These birds can be heard most of the time, but actually spotting them is quite a challenge. The only other species I spotted in the forest was a Thick-billed Pigeon and a large colony of Hill Myna feeding on the fruiting tree. The small grassland area around Nong Pack Chee wildlife viewing tower was a little bit more productive in terms of birds. There were Bright-capped Cicticola, Red-whiskered Bulbul, Barn Swallow and Hill Myna.
One afternoon we heard the heavy hoof sounds as we were coming out onto the grassland. Gaurs. They must have been sleeping in the tall grass no more than a couple of meters away from us and quickly retreated into the forest, disturbed by our appearance. As hard as we looked we could not spot them.
Reptiles are the only group that does not disappoint during the rainy season. We have spotted two different White-lipped Vipers, Oriental Whip Snake, male and female Scaly Bellied Lizards, Indo-Chinese Water Dragon, Reticulated Python at the bat cave, and two species of frogs. Insects were also abundant particularly crickets.
The bats in various caves around Khao Yai accounted for most of my mammalian sightings on this trip. One afternoon I joined the half day tour to see the local bat spectacle. The first cave we visited was as usual located at a temple. The cave was quite big and housed a few species of bats. The first one we spotted was a Horseshoe “Peter” that had a favorite place to roost in the cave and therefore was easily located. Further into the cave I spotted at least two different species of Roundleaf bats in the roosting colony.
Next stop – the main event – was a few kilometers from the temple. Here each day at dusk two million Wrinkle-lipped Bats emerge from their cave to hunt insects at night. Two million bats spilling out of a cave is indeed a wildlife spectacle. It seemed that the stream of bats would never end. Such high concentration of biomass is bound to attach a suit of predators. We watched Shikras launch into the stream of bats and pick an easy dinner. It took the bats about an hour to exit the cave and dissipate in the surrounding landscape.
Another day we arranged a visit to a different cave. This cave is not on the tourist itineraries as the climb up to it is very steep over uneven rocky ground. The track we were following was practically non-existent which made us feel like real explorers. A group of Long-tailed Broadbills provided a much needed reason for a rest stop during the climb.
Inside the cave itself the bats were wide awake. As a result of them being awake we became covered in their droppings within minutes of entering the cave. Tony managed to catch one of the roosting young and we were able to have a good look at him. The bats turned out to be the Cave Fruit Bats – the species that Tony studied for his PhD in Malaysia. He told us that these guys fly for over 50 km a night in search of food. During their roosting time they congregate in large colonies and take advantage of each individual’s knowledge about the flowering trees. Naturally, some individuals in the colony will be luckier than others at searching for food. These lucky few would have had a very good feed at night and their chests would still be covered in pollen. As they come in contact with other members of the colony, that pollen lets the others know which trees are currently in flower. The bats know where all the trees in their territory are and once they know which species are in flower, they head right to them the following night.