Northern Yellow Warbler

How to find it

Start in lowland to mid-elevation second growth, where a little pishing can bring Yellow Warblers in to investigate. Coffee farms are a good place to look, since birds return to the same plantation each winter. Gardens, farm edges and town trees are worth a scan too. Mangrove and wetland boat tours have given bright flashes of yellow warblers crossing rivers. Listen for the sharp 'seet' first, then look for the restless yellow bird.

How to recognise it

This is the only warbler with yellow flashes in the tail, so watch the tail as it flits.

- Length: about 11.5 cm

- Above: yellowish olive

- Below: yellow

- Face: plain, with no markings

- Wings: no contrasting wing bars

- Northern migrant males: chestnut streaking on the breast

Females look the same as resident mangrove females, so head colour only helps with males.

What it sounds like

Recording: Sydney Gerig, CC BY 4.0, source, read 4 Nov 2026.

Behaviour and diet

It forages actively for insects in foliage and sometimes catches them in short flights.

Wintering birds are usually solitary and defend a territory. On migration they may join other migrant warblers, but they seldom join mixed winter flocks.

That territorial habit fits a long banding study in southern Costa Rica near San Vito, which found the same birds returning to the same coffee plantation each winter.

Where it lives

In Costa Rica it is frequent in secondary forest, scrubby pasture, farmland, semi-open areas, towns, coffee farms, mangroves and gardens.

It is a common winter resident in the lowlands of both the Pacific and Caribbean slopes and reaches up to about 2150 m. The biggest migration waves pass along the Caribbean coast. Across its wider winter range, birds chiefly use mangrove swamps and similar dense woody growth.

When to see it

Northern birds arrive in large numbers in autumn, mostly September to October, with a few in mid-August, and they leave in early to mid May. Late October to early March is a good window to meet them among the winter warbler parade.

Similar birds

Costa Rica also has a resident, endemic Mangrove Warbler subspecies (xanthotera) restricted to mangroves, so look in mangroves for the resident form and elsewhere for the migrant. Resident males have an orange or rust head, while the migrant has only chestnut streaks on the breast. Female Hooded and Wilson's Warblers can also be yellow below and olive above, but neither has yellow edging on the wing feathers, and the Hooded has white tail patches. Many migrants sing variations that sound much like a Chestnut-sided Warbler.

Names and lore in Costa Rica

Reinita Amarilla is the name Costa Ricans use, and it covers both the migrant and the resident mangrove form, which the migrant was split from. The resident mangrove form also goes by cazadora, cazadorcilla and reinita de manglar.

Status and conservation

The AOCR lists it as M, a migrant, and Costa Rica is a wintering and passage area for this form, not a breeding area.

Photography tips

Pishing in second growth can draw the bird into view. Boat tours on mangroves and wetlands give chances as birds cross rivers. Photo colour can mislead, since a streaky, reddish-tinged bird at Sierpe mangroves sparked debate over migrant or resident.