Cerulean Warbler

How to find it

Plan around the migration window and head for the Caribbean foothills, between late August and late September. Look up and scan mixed species flocks moving through the high canopy. Checking Cecropia trees in migration season may help, since one Costa Rica birder spotted a Cerulean searching thick Cecropia foliage. In the Central Valley, two females were once seen foraging low in tall trees mixed with thick low vegetation. Experience with identification helps a great deal, so a guide who knows the flocks is worth having.

How to recognise it

This is a very small warbler, about 11 cm long, with a thin pointed bill. These marks describe the species in general.

Adult males are sky blue above and white below. They have a dark necklace across the breast and streaks on the back and flanks.

Females and young are blue-green above, with a pale eyebrow and yellow below.

All of them have two white wing bars. In Costa Rica the warblers are picked out from mixed species flocks moving through the high canopy, so experience with identification helps.

What it sounds like

Recording: Jonathan Layman, CC BY 4.0, source, read 4 Nov 2026.

Behaviour and diet

The Cerulean Warbler feeds on insects and forages and nests high in the canopy of mature forest, higher than many other warblers. In Costa Rica it moves with mixed species flocks through the high canopy. At Las Brisas it shares habitat with other migrants such as Blackburnian Warbler and American Redstart. Bird banders there call it a hard target, because it spends most of its time foraging in the upper levels of the forest.

Where it lives

Most Cerulean Warblers in Costa Rica use foothill and middle elevation forests on the Caribbean slope. Las Brisas Reserve stands out as especially important, and it sits on the slopes of the Turrialba volcano. Ceruleans can also turn up in the Central Valley, but seeing them there is hit or miss.

Costa Rica is only a passage stop. Wintering birds use Andean forests from Colombia and Venezuela south to eastern Ecuador and southeastern Peru.

When to see it

Las Brisas gets its Cerulean Warblers from late August to mid-September. Prime arrival in the Corredor Azul and Cerúlea Nature Reserve area is the last week of August and the first week of September.

Similar birds

Cornell lists the female or young Blackburnian Warbler and the non-breeding female or young Blackpoll Warbler as look-alikes. Both are migrants that can also pass through Costa Rica. Check the wing bars, the pale eyebrow and the blue-green tone of the back before you call it.

Names and lore in Costa Rica

The name on the Costa Rican bird list is Reinita Cerúlea. Other Spanish names for the species are Chipe Celeste and Chipe Cerúleo.

Status and conservation

The AOCR list marks it as a migrant (M), and worldwide it is Near Threatened, with populations falling because of severe loss of breeding and wintering habitat.

Photography tips

Even in good migration spots, most birders need a few days of searching to find a single Cerulean Warbler, so it is a patience bird for photographers. Check Cecropia trees in migration season, and give yourself several days rather than one.