Bird of the Month: Nashville Warbler
By Andy McCormick
PC: Mick Thompson (Nashville Warbler)
Scientific Name: Oreothlypis ruficapilla
Length 4.75 in
Wingspan 7.5 in
Weight 0.3 oz
AOU Band code NAWA
Originally found near Nashville, TN in 1811 by Alexander Wilson the Nashville Warbler is found in nearly every state, but does not breed anywhere near Nashville (Kaufman). It was once considered rare, probably because the eastern half of the U.S. was more heavily forested at the time. The Nashville Warbler prefers semi-open areas. “As cut-over and second-growth areas become more widespread, breeding opportunities for this species increase” (Lowther and Williams). As a consequence of deforestation the Nashville Warbler has expanded its range and has shown an increase in population.
The American Ornithological Union recently regrouped the warblers and created a new genus Oreothlypis, from the Greek oros, mountain or hill, and thlypis, a type of finch, for the Nashville and seven other warblers including the Orange-Crowned O. celata, another of our Northwest warblers. The Nashville has a small rufous crown patch which is hidden most of the time. This is the basis for the species name ruficapilla, Latin rufus, red and capillus, hair of the head (Holloway). There are Eastern and Western subspecies.
The head of the Nashville Warbler is gray with a clear white eye-ring. The head contrasts with the olive back, wings and tail. Sibley notes that the Western subspecies has gray extending beyond the head to the upper back. The underparts are bright yellow, especially in Western birds, and white feathers on the lower belly are more conspicuous in Western Nashvilles. The song is a sweet see-bit, see-bit, see-bit, see see see see see.
Nashville Warblers are early migrants and will be moving along the Pacific Flyway in April arriving in the Washington breeding area on the eastern slope of the Cascades from mid-April to mid-May (Dunn and Garrett). They can be quite secretive in the spring (Bell and Kennedy). They nest on the ground in varied habitats of generally mixed woodland and second growth forests which follow cutting or fire. Usually 4-5 eggs are deposited in a very well-hidden open cup nest made of grass, ferns and strips of bark. Incubation lasts about 12 days. Hatchlings leave the nest in another 11 days. Their diet consists of small beetles, caterpillars, grasshoppers and aphids (Kaufman).
Nashvilles winter in Western Mexico in a wide range of habitats including cloud forest, tropical deciduous forest and second-growth forests, and in thorn forest and pine-oak-fir forest. They also winter in central to southern Mexico to Guatemala (Lowther and Williams). It is an adaptable bird species that is responding to human intervention in the environment.