Bird of the Month: Townsend's Warbler
By Andy McCormick
PC: Mick Thompson (Townsend’s Warbler)
Scientific Name: Dendroica townsendi
Length 5 in
Wingspan 8 in
Weight 0.31 oz
AOU Band code TOWA
This boldly patterned warbler is a Pacific Northwest specialty that inhabits our coniferous forests. Townsend’s Warblers are a bright spot in the northwest’s gray winters and welcome visitors to the lowlands. They can occasionally be seen at suet feeders to the delight of backyard birders. This bird is part of a super-species known as the “virens (green) group” which is also comprised of Black-throated Green, Black-Throated Gray, Golden-cheeked, and Hermit Warblers. All have a distinctive black throat and all but the Golden-cheeked have a green back for which the group is named. Townsend’s Warbler is characterized by a black cheek patch at the auriculars surrounded by yellow, yellow on the chest with black streaks on the sides, and white wing bars. Its closest relative the Hermit Warbler Dendroica occidentalis, with which it often hybridizes near the Oregon-Washington border, has no black on the face and a white chest.
Dendroica ,tree dwelling, is the largest of the warbler genera and is from the Greek, dendron, tree, and oikos, house or dwelling. The species townsendi is for John Kirk Townsend (1809-1851), an ornithologist from Philadelphia who studied birds in the west. Warbler is for the trills and quavers of the song (Holloway).
In the breeding season Townsend’s Warbler prefers denser forests of grand fir, Douglas fir and Engelmann spruce. It forages at the tops of conifers for caterpillars, beetles and leafhoppers and will also sally out for flying insects. Its nest is a shallow cup made of grass stems, mosses and cedar bark and is constructed on the end of a high branch. Because of the height of the nests the breeding habits of Townsend’s Warbler have been difficult to study. Typically 4-5 eggs are deposited in the nest by early June. It is estimated that incubation lasts about 12 days and the birds leave the nest in another 10 days (Kaufman).
In spring Townsend’s Warblers begin arriving at higher altitudes in the northwest during April and settle on the breeding grounds in May. In fall Townsend’s Warblers migrate to lower altitudes and many winter in mixed woodlands close to Puget Sound and along the Pacific coast from British Columbia through California. The majority migrate to Mexico and Central America. In the north it appears that the birds are expanding their breeding range northward into Alaska, which may be similar to other bird species as a result of generalized warming trends. Because of its preference for dense forests Townsend’s Warblers are vulnerable to forest fragmentation. International conservation efforts are needed to protect dense old-growth forests in the north and higher altitude forests in the wintering range (Wright).
Many warblers are identified by sound and Townsend’s Warbler is no exception. Its song is a buzzy weazy weazy weazy dzeee or alternatively a buzzy zi-zi-zi-zi-zi-zi, zwee, zwee.