The Killing Skies of Gomantong.

The Killing Skies of Gomantong.

If you have an afternoon to spare when you are in Sandakan, do take a 2 hours drive out to the Gomantong Caves and see for yourself the natural spectacle of mass exodus of bats leaving the caves in endless streams.

Spirals of Wrinkled-lipped Bats streaming out of the Gomantong Caves at dusk.

Every evening since recorded history, more than a million bats, mainly Winkled-lipped Bats leave the Gomantong Caves in never ending spirals into the night skies. This awesome sight can last well into nightfall. The bats will spend the night feasting on insects all over the countryside before returning to the cave to roost before dawn.

Another drama is waiting to unfold. It will be a life and death encounter over the killing skies of Gomantong.

Meeting the colony of bats side on, the Bat Hawk is built for the kill.

The resident Bat Hawks and the Rufous-bellied Eagles have been spending the day resting up for this moment. It is a buffet not to be missed. The larger Wallace’s Hawk Eagles and smaller Peregrine Falcons will wait nearby for their turn as there is no need to rush and fight for such an abundance of food.

Cropped photo of about 300 bats in a single frame.

The Bat Hawks are specialised bat predators. With folded wings they will slice into the colony of bats, twist their bodies upright, push their talons up front and try to snatch at any of the bats that come close to it. Once in a while it will miss catching one or the bat somehow managed to wriggle out of its grasp. But it will be a matter of time before the Bat Hawk gets its talon on one. It will tear and eat it on the wing to save the trouble to coming back for another.

The Bat Hawk locking on to a bat with its talons by twisting its body backwards.

The Rufous-bellied Eagle is less agile. It will have to fly into the cloud of bats several times before getting hold of one. The smaller Peregrine Falcons are known for their speed and they use it to good effect. They will thermal higher up above the colony of bats and then dive down for the kill. Their success rate is almost 100%.

The adult Rufous-bellied Eagle had to make several dives before catching one.

On the day of observation, the Wallace’s Hawk Eagle was the less interested and did not join in the killing frenzy. It perched nearby watching the spectacle even as the bats were flying directly overhead. Maybe it had its fill or was just waiting for its favourite species to appear.

The Wallace’s Hawk Eagle perch just below the colony of bats waiting for the right time to hunt.

I was ecstatic to be able to witness and capture this life and death drama, mother nature’s wonder, over the killing skies of Gomantong.

Reference: John MacKinnon and Karen Phillipps. A Field Guide to the Birds of Borneo.