Hornbills perched outside of a cave pick off bats as they exit

Every evening at dusk, millions of tiny bats pour out of Borneo’s Gomantong Caves in a thick, living river that stretches across the sky for over an hour. Local oriental pied hornbills have figured out that this is the easiest all-you-can-eat protein buffet they’ll ever find. Instead of trying to chase the bats in open flight (which they’re terrible at), the hornbills simply pick a good branch right in the flight path, perch quietly, and wait.

National Geographic