Henderson Island (Pitcairn Islands)
Land bird populations appear to be relatively stable. The big problem is that when yachts land on the island without authorization, they introduce new predators, disease vectors or diseases. Introduction of the Eurasian black rat or the domestic cat would be likely to cause almost immediate extinction of the ground-dwelling Henderson crake and possibly other species. The endemic birds may have no immunity to the fatal avian pox which is transmitted by biting flies.