Black-throated Blue Warbler - Taxonomy and Phylogeny

Taxonomy and Phylogeny

The German naturalist Johann Friedrich Gmelin described the Black-throated Blue Warbler in 1789. Its species name is the Latin adjective caerulescens "turning blue".

The Black-throated Blue Warbler is one of the New World Warblers or wood-warblers in the family Parulidae. This species was originally placed under the genus Dendroica. It was recently adjusted to be a member of genus Setophaga along with all other members of the genus Dendroica, based on the findings from a recent phylogenetic analysis of mitochondrial DNA and nuclear DNA in 2010. The old genus Dendroica was then deleted.

The species breeds in North America and winters in the Caribbean. Some studies have observed significant differences in terms of migratory behavior and plumage color between northern and southern populations within the breeding range. The northern population mainly winters in the western Caribbean while the southern population usually spends the winter on eastern islands. Moreover, males in the southern population have darker plumage than those in the northern population. These differences have led biologists to consider them as separate subspecies. However, a recent study in the United States reveals no significant genetic differentiation between northern (samples from Michigan, New Hampshire and New York states) and southern populations (sample from North Carolina). The study results actually show a recent population expansion from a single glacial refugium, therefore the current populations are homogeneous in terms of genetics. The differentiation that is observed between the northern and southern populations should have occurred quite recently.