The three species are:
- Hooded warbler, Wilsonia citrina
- Wilson's warbler, Wilsonia pusilla
- Canada warbler, Wilsonia canadensis
Wilsonia warblers are 12–13 centimetres (4.7–5.1 in) long. They have yellow underparts and black head markings in at least the adult male plumage. Two species have plain olive green-brown back, but the Canada warbler has grey upperparts and is also migrates much further than the other species in the genus.
The breeding habitat is broadleaved woodlands with dense undergrowth. These birds nest low in a bush or on the ground, laying 3–6 eggs in a cup nest.
Wilsonia warblers feed on insects, often caught by flycatching, and they have distinctive songs and loud chip calls.
Recent genetic research has however suggested that the type species of Wilsonia (hooded warbler W. citrina) and of Setophaga (American redstart S. ruticilla) are closely related and should be merged into the same genus. As the name Setophaga (published in 1827) takes priority over Wilsonia (published in 1838), hooded warbler would then be transferred as Setophaga citrina. Where this is accepted, the other two Wilsonia species are then transferred to their next-most closely related genus, Cardellina. This change has been accepted by the North American Classification Committee of the AOU, and the IOC, however the South American Classification Committee of the AOU continues to keep Wilsonia in use.
This genus was named to commemorate the American ornithologist Alexander Wilson.
- Dunn, Jon; Garrett, Kimball (1997). Warblers. New York: Houghton Mifflin. p. 571. ISBN 0-395-78321-6.
- Lovette, I. J. et al. (2010). A comprehensive multilocus phylogeny for the wood-warblers and a revised classification of the Parulidae (Aves). Molecular Phylogenetics and Evolution 57 (2): 753-770. Abstract
- Chesser, R. T. et al. (2011). Fifty-Second Supplement to the American Ornithologists’ Union Check-list of North American Birds. Auk 128 (3): 600-613 fulltext