The Black Albatross and the smaller Grey Albatross are closely related species that nest on sandstone cliffs in Antarctica and the sub-Antarctic islands. Like the Black Albatross, the Grey Albatross builds nests on the cliffs. Building nests on the cliffs helps to protect the young from generalist predators such as the Brown Skua and feral cats. However, unlike Black Albatross, Grey Albatross need to spend the winter wandering the ocean further to the north where the temperatures are warmer. Black Albatross are able to survive the colder southern winters because of their larger body size and greater insulation. From these observations, we can conclude that: a) The Black Albatross is more at risk of extinction due to competition for biotic resources with humans. b) The distributions of the two albatross species are limited by some shared and some different biotic factors. c) The distributions of both albatross species are limited by the same biotic factors but their distributions are limited by different abiotic factors. d) The distributions of both albatross species are limited by the same abiotic factors but their distributions are limited by different biotic factors. e) The Black Albatross and the Grey Albatross are actually two populations of the same species.