Grey-headed warbler  (Basileuterus griseiceps)

The grey-headed warbler is classified as Endangered (EN) on the IUCN Red List (1).

The grey-headed warbler (Basileuterus griseiceps) belongs to a family of birds often described as ‘jewels of the forest’ due to their areas of dazzling, brightly coloured plumage (2). As its name suggests, this species has a grey head, with distinctive white spots above the eyes and white speckling on the ear-coverts. Its upperparts are deep olive-green, and its underparts and throat are a bright yellow colour (3). The grey-headed warbler has tiny, flesh-coloured legs and a black bill (4).

Both the male and female are similar in appearance. The juvenile has a dark grey hood extending down the breast, its body is brown and its underparts and legs are paler (4).

The grey-headed warbler’s song consists of a lively ‘(hu)wee-che-tseew’. A thin ‘tsip’ call is used in communicating with other birds, and a harsher ‘tseck’ or ‘chack’ is used when the warbler is excited (4).

The grey-headed warbler is endemic to northeast Venezuela. This species has a small range, and has recently been recorded in just seven locations in the Cordillera de Caripe, a mountain range in Venezuela (3).

The grey-headed warbler is found in a variety of forest habitats, including undisturbed montane and cloud forest. It also inhabits forest edges and clearings, where the understory is very dense. This species may survive in disturbed forest where the understory remains intact, although its abundance is lower in fragmented forests (3) (4).

Although little is known about the breeding habits of the grey-headed warbler, species in the Parulidae family, also known as New World warblers, are all believed to have similar reproductive behaviours (5) (6). The male and female usually remain pair-bonded throughout the breeding season. Three eggs are typically produced per clutch, although the number of eggs laid varies according to the amount of food that is available. The incubation period usually lasts 12 days, and during this period the female stays with the eggs while the male provides food (2). The breeding season for the grey-headed warbler begins in May and July, and juveniles fledge in August (3).

The nest of the grey-headed warbler is shaped like a domed cup, and has a side entrance. It is built mainly with bamboo leaves and palm material and is usually found approximately 1.5 metres above the ground (4).

Like other species of New World warbler, the grey-headed warbler feeds mainly on insects (2) and other invertebrates (4). Its thin, pointy bill is well adapted to foraging for its small prey, and it may also forage for seeds and berries. This species is elusive, and will flit at high speed from branch to branch (2).

The main threat to the grey-headed warbler is habitat destruction. Large areas of the Cordillera de Caripe have been cleared for agriculture and pasture. Forest clearing and burning for coffee and fruit plantations are degrading the montane forest habitat, reducing the available understory on which the grey-headed warbler depends for survival (3).

Large areas of the grey-headed warbler’s habitat are protected within El Guácharo National Park, and the reserve was recently expanded to include a further 500 square kilometres of largely undisturbed forest. Increasing the area of protected habitat further will help protect the grey-headed warbler (3).

View information on this species at the UNEP World Conservation Monitoring Centre.

More information on the grey-headed warbler:

• BirdLife International - Grey-headed warbler:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=9175