Worm-eating Warbler

How to find it

Go into the forest interior rather than staying at the edge, because this warbler keeps to closed-canopy forest with plenty of understory. Look low, in dense thickets and tangles of undergrowth. Scan clusters of hanging dead leaves, where it searches for food. Listen for the loud chip, since it often goes unnoticed until it calls. Check mixed flocks in forested habitats. The Caribbean side of the country is a sensible place to start.

How to recognise it

This is a plain olive and buff warbler, and the head is where the interest lies.

Look for:

- bold dark stripes on the crown

- bold dark stripes behind the eye

- plain olive and buff plumage on the rest of the bird

- no difference between the sexes, since males and females look alike

Because the body is so understated, the head pattern is the feature to check when a bird shows itself in the undergrowth. That pattern, together with a low, solitary bird picking at dead leaves, points firmly to this species.

What it sounds like

Recording: annegp, CC0 1.0, source, read 4 Nov 2026.

Behaviour and diet

This is a bird of the lower levels. It stays low to the ground and searches through dense tangles of undergrowth. In the tropics in winter it forages alone, so be ready for a solitary bird rather than a flock.

In winter it mostly searches clusters of hanging dead leaves for food, and on the wintering grounds it takes insects almost only from dead plant material. A Costa Rican birder calls it a professional dead leaf searcher. It is regularly met with mixed flocks in forested habitats.

Where it lives

Costa Rica is one of the countries where northern-breeding Worm-eating Warblers spend the northern winter. The winter range runs from Mexico south through Central America to Panama.

On the wintering grounds the species has been reported in a wide variety of wooded habitats, and in the nonbreeding season it may also turn up in scrub and second-growth forest. It mostly stays in the interior of closed-canopy forest with plenty of understory. Across the region it winters in moist forests, especially on the Caribbean slope. In Costa Rica it has been recorded in the Monteverde cloud forest in Puntarenas and listed at Cloudbridge Nature Reserve.

When to see it

Worm-eating Warblers were seen at Parque Rio Loro in early October, when fall migrants are arriving. There is also a March record from the Monteverde cloud forest, dated 16 March 2004.

Similar birds

It can resemble a Northern Waterthrush, which has a darker brown back, brown head stripes and a streaked breast. At Parque Rio Loro, Worm-eating Warblers shared the forest floor with Northern Waterthrushes, which pump their tails, and with Ovenbirds, which chip as they walk along branches.

Names and lore in Costa Rica

In Costa Rica the bird is called Reinita Gusanera. Other Spanish-speaking countries use different names: chipe gusanero in Mexico, chipe comegusanos in Honduras, and reinita anteada in Nicaragua.

Status and conservation

On the AOCR list it is a migrant (M), a visitor from the north that does not breed in Costa Rica, and BirdLife International rates the species as Least Concern.

Photography tips

Look low and be ready for a solitary bird, since in winter it forages alone in dense thickets or forest undergrowth, usually near the ground. Enter the forest interior and let the loud chip guide you to it.