Blue-black Grosbeak

How to find it

Listen first for the descending whistles, then work slowly toward the sound in shaded understory. Try humid lowland forest, forest edges and tall second growth. Watch mixed flocks at the forest edge, since one joined Carmiol's Tanagers at Arenal for a rare open view. Early morning walks on forest trails in the southern Pacific region near Corcovado have turned one up in late January or early February. At Carara, one tour group only heard it at first and then finally got a clear look.

How to recognise it

The adult male is dark blue-black, blackest on the wings, tail and lores, with a short, faint, brighter blue forehead and brow. He is about 16.5 cm long.

The bill is the feature to look for: very thick, dark and cone-shaped, massive and triangular, nearly as thick at the base as the head.

The female is deep brown above and slightly paler below, with a darker breast. Her bill is black with a silvery base to the lower half.

A young male is brownish with only patches of blue-black, mostly on the head. Birds that are entirely brown are females or possibly young males.

What it sounds like

Recording: Rajan Rao, CC BY 4.0, source, read 4 Nov 2026.

Behaviour and diet

This is a secretive bird that normally stays hidden in deep cover, which is why it is heard far more often than seen. It eats fruits, seeds and insects such as beetles, roaches, ants and caterpillars, and it crushes seeds before eating them.

It also enters lower second growth and grain crops to feed. Now and then one joins a mixed flock at a forest edge: at Arenal, birders watched one perch in the open with a flock of tanagers, which the guides called unusual.

Where it lives

In Costa Rica it ranges from sea level up to about 1200 m. It lives in the understory of humid forest, dark ravines, and tall, partly open, shaded second growth.

It is a common resident on the Caribbean slope and the southern Pacific slope. It is locally common in gallery forest and damp ravines on most of the Nicoya Peninsula and around the Gulf of Nicoya, including the lower Tempisque valley. It is absent from northern Guanacaste and from the Central Valley.

When to see it

In Costa Rica it breeds from March to September, mostly in July and August, and raises two or three broods a year.

Similar birds

The female looks like a female Nicaraguan Seed-Finch (Oryzoborus nuttingi), but she is slightly larger and lives in denser habitat. The male's massive, triangular black bill separates it from the similar Blue Bunting, which shares its habitat in Central America.

Names and lore in Costa Rica

Besides the official Costa Rican name Picogrueso Negro Azulado, the species is also called realejo negro, picogrueso negriazul and picogordo negro in other Spanish-speaking places.

Status and conservation

It is a resident (R) on the AOCR list, and the IUCN lists the species as Least Concern.

Photography tips

Expect to hear it long before you see it, and plan for patience. A mixed flock at a forest edge offers the best chance of an open view. Birds that strike windows are a recorded source of photos in Costa Rica, a reminder of how secretive the species is.