Sooty Grassquit

Overview

The sooty grassquit, Asemospiza fuliginosa, is a small bird in the tanager family, Thraupidae, recognised as a species of Least Concern by the IUCN. It possesses an extremely disjunct distribution across various regions of South America and the Caribbean.

Identification

• Adults are sexually dimorphic, with males displaying a sooty blackish plumage featuring an olive tinge on the back and slightly paler underparts, while females are a rich olive-brown that is darker on the upperparts than the underparts.
• The bird is small, measuring between 10 and 11.4 cm in length and weighing 11 to 16 g.
• Both sexes possess a dark bill, with females having a slightly lighter shade, along with dark irises and dark legs and feet.
• The song is described as a simple, extremely high, and fast variation on 'zizi-tsuur-sjree', or a thin, wiry, and slurred 'ezz'u'da'leé' with a peculiar buzzy quality.

Habitat

The species inhabits the edges of moist to humid forests, grassy areas both within and outside the forest, and regrowing burned areas. It ranges from sea level to 1,500 m in different parts of its territory and is found in Trinidad, Colombia, Venezuela, Guyana, Brazil, Paraguay, and Argentina, with vagrant records in Bolivia.

Diet

It feeds primarily on the seeds of bamboo, including Guadua and Chusquea, and is suspected to consume Merostachys seeds as well. It supplements this diet with smaller amounts of grass seeds and some fruit, foraging singly or in pairs during the breeding season, and in flocks of about 40 individuals outside that period.

Did you know?

Its population numbers are difficult to assess in many areas because its 'eruptive behaviour' makes its true status unpredictable. The species wanders into burned areas and in search of seeding bamboo, with its breeding season tied to the local bamboo seeding cycle.