The Yellow Warbler (Dendroica petechia) is a New World warbler. It is the most widespread Dendroica species, breeding in almost the whole of North America and down to northern South America.
Systematics and description
The Yellow Warbler has 35 subspecies, which can be divided into three main groups. Each of these groups is sometimes considered a separate species, or the aestiva group (Yellow Warbler) is considered a species different from D. petechia (Mangrove Warbler):
- The Yellow Warbler proper (aestiva group) breeds in the whole of temperate North America as far south as central Mexico in open, often wet, woodland or shrub. It is migratory, wintering in Central and South America. This form is a very rare vagrant to western Europe. It is 11.5 cm long and weighs 9 g. The summer males of this group are greenish above and yellow below, with red breast streaking. The various aestiva group races vary mainly in brightness.
- The Mangrove Warbler (erithachorides group) is larger at 12.5 cm and weighs 11 g. It is resident in the mangrove swamps of coastal Central America and northern South America. The summer males differ from aestiva group warblers in that they have rufous hoods. The races in this group vary in the extent and hue of the hood.
- The Golden Warbler (petechia group) is resident in the mangrove swamps of the West Indies. The Cuban Golden Warbler (D. p. gundlachi) barely reaches the Florida Keys where it was first noted in 1941, and by the mid-20th century a breeding population was resident. Though individual birds may stray farther north, their distribution is restricted by the absence of mangrove habitat. The summer males differs from aestiva group warblers in that they have a rufous crown or hood. The races in this group vary in the extent and hue of the head patch.
Other plumages of all races are essentially greenish above and a duller yellow below, although young males soon acquire breast and, where appropriate, head colouration. Females are somewhat duller, most notably on the head.
The song is a musical sweet sweet sweet, I'm so sweet, although it varies considerably between races. The call is a soft or harder ship.
These birds feed on insects and spiders, but northern races will also take some berries, namely in their winter quarters.
The migratory populations arrive in their breeding range in late spring - generally about April/May - and move to winter quarters again starting as early as July, when the young are fledged. Most, however, stay a bit longer; by the end of August, the bulk of the northern populations has moved south, though some may linger almost until fall. At least in northern Ohio, Yellow Warblers do not seem to remain on their breeding grounds longer than they did 100 years ago.
Yellow Warblers nest in trees, building a cup nest. Birds of the aestiva group lay 3–6 eggs, but the two other groups, which breed in mangroves, lay fewer eggs, as would be expected for tropical races.
The Yellow Warbler is a regular host of the Brown-headed Cowbird, a nest parasite, and it has evolved strategies to combat such nest parasitism. Upon discovering a cowbird egg laid in its nest, the warbler will often build a new layer to the nest, covering up the cowbird egg (and its own eggs, if they have been laid). In other circumstances, the bird may desert the nest altogether.
- Database entry includes justification for why this species is of least concern
- (1966): A Florida winter specimen of Dendroiva petechia gundlachi. Wilson Bull. 78(2): 232. DjVu fulltext PDF fulltext
- (1994): New World Warblers. Christopher Helm, London. ISBN 0-7136-3932-6
- (2007): The potential of fruiting trees to enhance converted habitats for migrating birds in southern Mexico. Bird Conservation International 17(1): 45-61. PDF fulltext
- (1906): A preliminary list of the birds of Seneca County, Ohio. Wilson Bull. 18(2): 47-60. DjVu fulltext PDF fulltext
- (2004): Annotated Ohio state checklist. Version of April 2004. PDF fulltext