Cocos Finch

How to find it

Start at the Wafer Bay ranger station on Cocos Island, where visitors meet the finch. A few gather on the porch rafters and rails during coffee breaks. They hop closer to food, so they let people get very near. Away from the station, look in the lowlands first, where it is more abundant, though it turns up at all elevations. Because it is the most abundant land bird on the island, it is easy to find once you are ashore.

How to recognise it

Adult male: entirely black.

Female: dark brown above, buff below, with dark streaking.

Bill: slightly curved and pointed, long and thin compared with other Darwin's finches.

Size: adults measure about 12 cm.

Young birds look like the adult female but have a yellow bill. Now and then a black male with a yellow bill is seen, so a yellow bill does not always mean a female-like youngster.

As a beginner you can lean on one reassuring fact: it is the only finch on its island, so there is little to confuse it with.

Behaviour and diet

Cocos Finches move about restlessly in pairs or small groups. Each bird tends to stick to its own favourite feeding method: one may hunt insects while another takes fruit or nectar, and researchers think they learn this by watching each other.

The nest is a loose ball of grass stems, twigs and dry leaves, with a side entrance. It sits at the tip of a branch, usually 2 to 9 m up. Breeding runs from January to May, although some nesting happens all year.

Where it lives

The finch uses every habitat on Cocos Island, including coastal hibiscus thickets, closed forest and woodland. It is seen at all elevations but is more abundant in the lowlands, and it also uses disturbed vegetation.

In Costa Rica it is found only on Cocos Island, in the Pacific. Its whole range is only about 25 square km, and the entire island lies within Isla del Coco National Park.

When to see it

The finch lives on Cocos Island all year and does not migrate. Breeding happens year-round, with a peak from January to May.

Similar birds

The Cocos Finch has no lookalikes on its island, because it is the only finch there. Its long, thin, curved bill sets it apart from other Darwin's finches. It resembles the Galápagos finches, but it feeds as a generalist while those species are specialists, so behaviour tells them apart.

Names and lore in Costa Rica

In Costa Rica the bird goes by Pinzón de la Isla del Coco. Other Spanish names are Pinzón de Darwin de la Cocos and Pinzón de Cocos.

Status and conservation

The AOCR lists it as a resident endemic (R-END), and it is rated Vulnerable because of its very small range, though it is common, with an estimated 6,000 to 15,000 mature birds.

Photography tips

The finches at the Wafer Bay ranger station hop closer to food and let people get very near, so the porch rafters and rails are the place to try. Watch for restless pairs or small groups moving through the trees elsewhere.