Setophaga is a genus of birds of the New World warbler family Parulidae. It contains at least 34 species. The Setophaga warblers are an example of adaptive radiation with the various species using different feeding techniques and often feeding in different parts of the same tree. Most Setophaga species are long-range migrants, wintering in or near the New World tropics and seasonally migrating to breed in North America. In contrast, two Setophaga species, the palm warbler and yellow-rumped warbler, have winter ranges that extend along the Atlantic coast of North America as far north as Nova Scotia. The males in breeding plumage are often highly colorful.

Taxonomy

The genus Setophaga was introduced by the English naturalist William Swainson in 1827. The type species was subsequently designated by Swainson in the same year as the American redstart Setophaga ruticilla. The genus name is from Ancient Greek ses, "moth", and phagos, "eating". Traditionally, most members (29 species) of Setophaga were recognized as belonging to the genus Dendroica. The only member of Setophaga was the American redstart. More recent genetic research suggested that Dendroica and Setophaga be merged. This change was accepted by both the North American and South American Classification Committees of the American Ornithological Society and the IOC World Bird List. As the name Setophaga (published in 1827) takes priority over Dendroica (published in 1842), those who accept the merger transferred all Dendroica species to Setophaga.

History

A burst of speciation in Setophaga occurred between 4.5 and 7 million years ago. This time frame roughly corresponds to the transition from the Miocene to the Pliocene period, when an abrupt rise in temperature and the fragmentation of forest habitats in North America may have caused allopatric speciation in the genus. It is widely agreed that this speciation constitutes an adaptive radiation, though recent evidence is mixed, noting that evidence of both adaptive and non-adaptive radiations exists. Up to several Setophaga species coexist in regions such as northeastern North America. Since these species are strikingly similar in both diet and morphology, this was once thought to be a violation of the laws of evolution. Further study concluded that species coexist through subtle feeding differences due to niche partitioning and diffuse exploitative interspecific competition : rather than compete directly for the same food resources, species utilize slightly different feeding strategies to capture a slightly different set of prey species.

List of species

The genus contains 37 species. They are: