Cocos Island is a forest-covered volcanic island in the eastern Pacific Ocean, some 500 km south of Puntarenas in Costa Rica of which it is politically a part. It is the point of land nearest to the Galápagos Islands, which lie 630 km to the south-west.

The island comprises primarily a dense forested plateau (at 400-700 m) rising steeply through wooded ravines from sea-level. Closed-canopy forest (cloud forest at 500 m and above) covers c.95% of the island and remains largely undisturbed, although there are some areas of second-growth forest and cleared land. Hibiscus scrub is found along the relatively flat, narrow coastal strip, and other habitats present include Annona swamp.

Three of the four resident landbirds are endemic to the island, all three being distributed throughout in varying abundances: the widespread (non-endemic) Yellow Warbler Dendroica petechia is also resident (Slud 1967). All available habitat types appear to be used by the three endemics, but thickets of Hibiscus seem to be favoured. Coccyzus ferrugineus is widespread but the least common of the native landbirds on Cocos Island, although population data are not available and it seems likely that the species is under-recorded in the interior forests (Slud 1967, Stiles and Skutch 1989). Pinaroloxias inornata, the only Darwin's finch (Geospizini) occurring outside of the Galápagos Islands (EBA 031), occupies every available habitat, being abundant in the Hibiscus thickets along the coast but sparser in the wet highland forest (Smith and Sweatman 1976, Stiles and Skutch 1989). Nesotriccus ridgwayi is common throughout the forest and other habitats including Hibiscus scrub, Annona swamp and wooded ravines (Sherry 1985, Stiles and Skutch 1989).

All three restricted-range species in this EBA are classified as Vulnerable by virtue of their exceptionally small ranges. Although Cocos Island is, in its entirety, a national park (and still covered in forest), it has been the subject of general disturbance from increasing ecotourism, but more importantly, overgrazing and browsing caused by introduced (and now feral) deer, pigs and goats, and predation of the native avifauna by introduced cats and rats (T. W. Sherry in litt. 1985). The impact of these threats on the avifauna is essentially unknown, and studies are clearly needed.

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Cocos Island. Downloaded from https://datazone.birdlife.org/eba/factsheet/21 on 23/11/2024.