Wilson's Warbler
Wilsonia pusilla

Migratory Status: Neotropical migrant

PIF Population Estimate: 36 000 000

Percent of western hemisphere population breeding in boreal forest: >25%

BAM Effective Detection Radius (m) : 61.6

PIF Maximum Detection Distance (m) : 100

Canadian BBS Population trend: -4.2 (-6.8 to -1.6)

Life History

Named after one of North America’s pre-eminent naturalists, Alexander Wilson, the Wilson’s Warbler is perhaps one of the more striking and easily identified wood warblers. Despite its relatively small size, the glowing yellow body plumage and black cap are easily identifiable features of adult males. Females have slightly muted, olive-toned plumage, but can be difficult to distinguish from males in the field.

The species’ breeding range includes almost all of the forested lands within Canada, and the majority of the state of Alaska. South of the border in the United States, the breeding range includes most of the mountainous west, extending south to southern California and northern New Mexico. The winter range includes portions of the upper Texas coast and western Louisiana. The bulk of the winter range extends from northern Mexico, south to west-central Panama.

The Wilson’s Warbler is primarily insectivorous on the breeding grounds and eats a variety of terrestrial invertebrates. Occasional observations of foraging on berries suggest that the species uses a wider range of food items on the wintering grounds. Food items picked directly from branches and leaves, or captured in the air during short flights.

Reference(s)

Ammon, E. M., and W. M. Gilbert. 1999. Wilson's Warbler (Wilsonia pusilla), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/478