Cocos Booby

How to find it

Boat trips are a good way to see it. Photos have been taken at sea off Punta Marenco, off Playa Hermosa and off the Nicoya Peninsula. From shore, Manuel Antonio National Park is another place where it has been photographed. Look near small islands close to shore, where these boobies are most numerous. A boat that finds feeding flocks is also a good way to see it plunge-diving.

How to recognise it

Adults are brown with a white belly. Males have a white or greyish frosting on the head, sometimes reaching the neck. Bill, face and throat pouch colour also differ between the sexes, so look closely at both birds of a pair.

The species is about 64 to 74 cm long. Males are smaller than females, but only slightly.

A female Cocos Booby has a pinker bill and a paler forehead than a female Brown Booby. That is the clearest way to separate them, because adult females look very much alike.

Young birds look more like dark forms of the Red-footed Booby.

What it sounds like

Recording: Dan MacNeal, CC BY 4.0, source, read 4 Nov 2026.

Behaviour and diet

This is a seabird of colonies. Visitors meet it on small rocky islets off the Pacific coast, where it nests in groups, and one Costa Rican nature blog photographed a Pacific islet colony. Colonies are the likeliest place to see many birds together.

It eats mainly small fish near the surface, caught by diving. It feeds in mixed flocks where upwellings push fish to the surface, especially when dolphins or tuna chase them from below.

Where it lives

Isla del Coco, about 550 km southwest of the Costa Rican mainland, is a breeding site. Large colonies sit along its cliffs and on the northern islets, and a seabird study calls this booby possibly the most abundant of the four boobies breeding there.

Closer to the mainland, Pacific birds nest on islands along the coast, but not in the Gulf of Nicoya. Photographers have also recorded it along the Pacific coast, so the open sea and the islets near shore are where to look.

When to see it

On islands near Costa Rica, breeding happens from October to February. A Costa Rican source written before the split says Pacific birds may breed all year, with a peak from September to April.

Similar birds

The bird most likely to cause doubt is the female Brown Booby, which looks very much like a female Cocos Booby. Check for the pinker bill and paler forehead of the Cocos. Location helps too, since Brown Booby is the one on the Caribbean side. A young Cocos can pass for a dark-morph Red-footed Booby. On the Pacific side and at Isla del Coco almost all Red-footed Boobies are the uniform grey-brown dark morph, and their legs look greenish when immature.

Names and lore in Costa Rica

Costa Rica's Spanish name list gives Piquero de Cocos, with Monjita and Alcatraz as other names, and Piquero Moreno for the Pacific booby that is now the Cocos Booby. Older Costa Rican names for the booby that included this bird are piquero moreno, piquero pardo and alcatraz pardo. Piquero de Brewster is another Spanish name often used for the species.

Status and conservation

The AOCR list marks it as a resident (R), and the 2024 update added it to Costa Rica's list as a species separate from Brown Booby.

Photography tips

It feeds in mixed flocks where upwellings push fish to the surface, especially when dolphins or tuna chase them from below. A boat that finds these feeding flocks is a good way to see it plunge-diving.