Adelaide's Warbler

Overview

Adelaide's Warbler (Setophaga adelaidae), known locally as reinita mariposera, is a New World warbler endemic to the archipelago of Puerto Rico. It is a year-round resident that is considered common in the western part of the main island and less so in the east, with a stable population assessed as Least Concern by the IUCN.

Identification

• Size: Approximately 12.5 cm (4.9 in) in length.
• Plumage: Adult males display a slate-gray crown with a thin black stripe, a wide yellow supercilium that thins to white behind the eye, slate-gray upperparts, and lemon-yellow underparts fading to paler yellow on the belly.
• Markings: Wings are mostly dull black with two white wing bars; the tail features white ends on the inner webs of the outer three pairs of tail feathers. Females have duller plumage with less white on the tail, while juveniles lack the black crown stripe and have narrower supercilia.
• Song: A loud trill that varies in pitch and speed, with individual birds capable of producing more than 20 variations. Calls include a quiet high-pitched pip, bursts of a loud harsh chit, and a chip.

Habitat

Found on the main island of Puerto Rico (excluding the extreme eastern end) and in the island municipality of Vieques. The species prefers dry forests, such as Guánica State Forest, as well as the Northern Karst Belt, flatter areas of the Cordillera Central, secondary forests, shade coffee plantations, and citrus orchards. On Vieques, it inhabits dry forest on limestone and dry scrublands.

Diet

Feeds on a wide variety of insects and other arthropods, obtaining at least half its prey by gleaning from leaves, but also capturing food from other substrates, during brief hovers, and in mid-air. Foraging occurs from ground level up to at least 10 m (33 ft) above it, and the species often joins mixed-species feeding flocks that may include Puerto Rican todies, vireos, and other New World warblers.

Did you know?

Adelaide's Warbler is named after Maria Antoinette Adelaide Florentia del Carmen Swift (1829–1884), the daughter of collector Robert E. G. Swift, who collected the first specimen of the species in 1865.