Black-whiskered Vireo (Vireo altiloquus)

Black-whiskered Vireo

Description

The black-whiskered vireo (Vireo altiloquus) is a small passerine bird, which breeds in southern Florida, USA, and the West Indies as far south as the offshore islands of Venezuela. It is a partial migrant, with northern birds wintering from the Greater Antilles to northern South America. This species has occurred as a rare vagrant to Costa Rica. This vireo is 14–15 cm in length, has a 25 cm wingspan and weighs 17–19 g. It has thick blue-grey legs and a stout bill.

Distribution And Habitat

The Black-whiskered Vireo occurs in the Southeastern United States, northern South America, and throughout the West Indies (Raffaele and others 1998). It is a common spring and summer resident in Puerto Rico, very abundant (March–August) in forested or wooded areas on the island (Oberle 2018, Raffaele 1989a), but uncommon in Vieques (Gemmill 2015). It has also been reported from Mona and Desecheo (Ventosa-Febles and others 2005). Most individuals migrate to South America for the winter, although some individuals remain on the island during the non-breeding season. This species inhabits forests of all types and elevations, woodlands, tall undergrowth, mangroves, and gardens (Raffaele and others 1998). The atlas fieldwork yielded a total of 713 records within 355 hexagons or 74 percent of the 479 total hexagons (see map). Of the 355 hexagons where this species was found, breeding met the atlas definition of confirmed in 6 percent (20) of the hexagons, probable in 59 percent (211), and possible in 34 percent (122), while the species was observed in 1 percent (2) of the hexagons but without evidence of breeding (see map). Black-whiskered Vireo distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in Puerto Rico. Note: percentages may not total 100 due to rounding. 217Black-whiskered Vireo/Julián Chiví

Breeding Habits

The Black-whiskered Vireo constructs a cup-shaped nest made of various plant fibers and grasses hanging from the fork of a small branch in the canopy of a tree from May to June, according to previously published reports (Raffaele and others 1998). Atlas results show that this species may breed primarily from March to June, with fewer records later in the year when most vireos have migrated south (see chart). Results suggest that the Black-whiskered Vireo inhabits all forest types as it breeds within the subtropical moist forest life zone (59 percent of the hexagons), subtropical wet forest life zone (23 percent of the hexagons), subtropical dry forest life zone (17 percent of the hexagons), and in one hexagon within the subtropical rain forest life zone (see table and map).

Conservation

The Black-whiskered Vireo population trend is unknown, and due to its large distribution range, it is listed as a species of least concern by the IUCN (BirdLife International 2017). Locally, this species is not listed in any of the threatened categories of PRDNER and USFWS. In Puerto Rico, the Black-whiskered Vireo has a protected habitat in land of about 13 percent or 1071 km2 of the total area covered by the hexagons where evidence of breeding was found for this species (8420 km2).