Distribution and abundance of the tick Ixodes uriae in a diverse subantarctic seabird community

At Bird Island, South Georgia, we surveyed the distribution and abundance o f ticks on the vertebrate fauna and found only 1 species Ixodes uriae. We c lassified all seabird species into 3 groups: (1) seabirds nesting on the su rface of the ground solitarily, in dispersed groups of a few nests, or in c olonies with well-spaced nests; (2) seabirds nesting on the surface of the ground in dense colonies; and (3) seabirds nesting in dense colonies in bur rows or rock crevices. We detected I. uriae only on 3 species of the second group that nested in large, dense, persistent colonies, i.e., black-browed albatross (Diomedea melanophrys), gray-headed albatross (Diomedea chrysost oma), and macaroni penguin (Eudyptes chrysolophus). Ticks were found on the undersides of the feet on albatrosses but not on the undersides of the fee t on penguins. We hypothesize that the coarse pebble nests of penguins, com bined with the fact that their young walk around more than albatross young, make the environment on the underside of penguin feet more harsh and hosti le for ticks than the underside of albatross feet. Despite the great abunda nce of Antarctic fur seals (Arctocephalus gazella) on the island, we found no ticks on them.