Seabirds of Cocos Island, Costa Rica, and their conservation.

Seabirds of Cocos Island, Costa Rica, and their conservation. The marine avifauna of Cocos Island includes 32 species, 17 genera and nine families. Eight of these species are reproductive residents and 25 are visitors. Among visitors, eight are Nearctic migrants, 11 are tropical species and 13 correspond to the Eastern Pacific geographic range. According to presence/abundance observations, six species are abundant (18.75%), one, common (3.13%), three, uncommon (9.37%), ten, casual (31.25%) and twelve, accidental (37.50%). I recommend a study of human impact, the establishment of an official checklist and periodical monitoring of this avifauna, and a better spatial definition of the coastal marine belt. Rev. Biol. Trop. 56 (Suppl. 2): 133-149. Epub 2008 August 29.