Blue-winged Warbler

The Blue-winged Warbler, Vermivora cyanoptera, is a diminutive and vibrant New World warbler, measuring a mere 11.5 cm in length and tipping the scales at approximately 8.5 grams. The male is particularly striking during the breeding season with his bright yellow head, breast, and underparts, complemented by a narrow black line through the eyes and light blueish-gray wings adorned with two white wing-bars.

Identification Tips

When attempting to identify the Blue-winged Warbler, look for the following key characteristics: a bright yellow head and underparts with no streaking, a black line through the eyes, and blueish-gray wings with two diagnostic white wing-bars. The female is somewhat duller with less yellow on the crown, while immatures are olive green with wings similar to the adults.

Habitat

The Blue-winged Warbler favors open, scrubby areas for breeding. It is often found in abandoned fields with a mix of shrubs and trees, bordered by taller deciduous trees. These birds prefer habitats at higher elevations with a significant amount of grass and canopy cover.

Distribution

This migratory species breeds in eastern North America, from east-central Nebraska to southern Ontario, and eastward to New England, extending south to parts of the Carolinas, Georgia, Alabama, Tennessee, and Missouri. In winter, they retreat to southern Central America. They have been known to appear as rare vagrants in western Europe.

Behaviour

The Blue-winged Warbler is a migratory bird, showcasing a preference for higher elevation breeding grounds with ample grass and canopy cover. Males typically arrive at breeding sites before females, engaging in continuous song until a mate is found. Post-mating, the length and frequency of their song diminishes.

Song & calls

The Blue-winged Warbler's song is a series of buzzing notes, while its call is a sharp chip. The song plays a crucial role in various behaviors, including territory defense and mating.

Breeding

Nesting occurs on the ground or low in a bush, with the female laying four to seven eggs in a cup-shaped nest. She incubates the eggs for 10-11 days, and the altricial young fledge in 8-10 days. During the breeding season, males sing to attract females and to communicate with other warblers.

Similar Species

The Blue-winged Warbler is closely related to the Golden-winged Warbler, and where their ranges overlap, they can hybridize, producing two hybrid types: the Brewster's Warbler and the Lawrence's Warbler. The Brewster's Warbler resembles the Golden-winged but has a blue wing face pattern and variable amounts of yellow, while the Lawrence's Warbler looks similar to the Blue-winged with a wing pattern akin to the Golden-winged.

Diet and Feeding

The diet of the Blue-winged Warbler consists primarily of insects and spiders, with a particular fondness for those found on apple trees, walnut trees, and water hemlock. Adults may hang upside down to glean and probe leaves, gathering insect larvae to feed their young.

Conservation status

The Blue-winged Warbler is currently listed as Least Concern by the IUCN, indicating that, at present, there are no immediate threats to its population levels.