Coexistence, Coevoluation and Convergent Evolution in Seabird Communities

摘要: Ecological isolating mechanisms based on differences in size or breeding season operate many groups of related sympatric seabirds, but not the alcid species (Aves: Fam. Alcidae) found together Washington State. At least three six coexisting have similar diets, and all breed at same time year. They differ, however, their foraging zones sea appear to reduced interspecific competition by this means. Diverse aspects biology, behavior morphology ecology these alcids can be explained reference two sets selective factors–interspecific for food predation upon eggs, chicks adults. Species that fish inshore guard exposed cliff sites grouped into ubiquitous small colonies. carry singly frequently throughout day. These young develop rapidly about one—third adult weight, which they quit nest site. other extreme, feed far offshore provide burrows chick large colonies only a few off—shore islands. Chicks are visited night adults whose bills adapted carrying fish. grow slowly reach close weight before leaving nest. patterns repeated with considerable fidelity six—species community Northern Iceland, southern hemisphere seabirds are, general,differently organized.