The natural ecosystem on Hawadax Island in Alaska was disrupted in the 1780s when brown rats, Rattus norvegicus, swam to the island from a sinking ship and then rapidly increased their population size. The rats occupied a new niche on the island as predators. The rats ate the eggs and chicks of birds such as the black oystercatcher, Haematopus bachmani, and the glaucous-winged gull, Larus glaucescens. These birds make nests, lay eggs and rear their chicks on the beaches of the island.