The rafted flocks of Razorbills, as well as Puffins and Murres, respond to some unknown signal.
They all lift enmass, just before dark, and pour onto the island in just a few minutes. This
nightly influx slows as the breeding season gets underway and most of the birds are spending more
time on the island. After they get started, most of the birds will also spend each night on the island.