Males: The male has a gray head with a red crown patch. The eye ring is bold and white. The throat, belly and undertail coverts are yellow. The underparts are olive-green. Colors are duller in fall.
Females and Immatures: The head is grayish-olive and little to no red on the crown. The eye ring is a buffy color. The throat has a white color. Overall colors are duller as compared to the males.
FOOD: insectivorous (Ehrlich et al., 1988).
MATING SYSTEM: monogamous (Ehrlich et al., 1988).
BREEDING SYSTEM:
Where Breeds: The Nashville warbler breeds in saplings and thickets, woodland edges, shrubby parts of open woodland, secondary growth, and bogs (Baicicich and Harrison, 1997).
Nest: The nest is found most often on the ground in moss (sphagnum) or at the base of a shrub or tree (Baicicich and Harrison, 1997). The nest is a small cup made out of rootlets and fibers and is lined with hair (Baicicich and Harrison, 1997). The nest is built by the female in 7-9 days (Baicicich and Harrison, 1997).
Breeding Season: The breeding season begins in early May in the southern part of the range to late May in the northern part of the range (Baicicich and Harrison, 1997). The breeding season ends in late July (Baicicich and Harrison, 1997).
Eggs: There are between 4-5 eggs laid in a clutch (Baicicich and Harrison, 1997). The eggs are subelliptical to short subelliptical and white to creamy-white in background color (Baicicich and Harrison, 1997). The eggs are speckled chestnut-red to reddish-brown which is usually confined to a wreath at the larger end of the egg (Baicicich and Harrison, 1997). The average size of an egg is 15 X 12 mm (Baicicich and Harrison, 1997).
Incubation: The time period is 11-12 days and is done by the female, rarely the male (Baicicich and Harrison, 1997).
Nestling: The young are born altricial and downy, the down is dark brown in color (Baicicich and Harrison, 1997). The mouth is reddish with a yellow gape (Baicicich and Harrison, 1997). The bill and feet of the nestlings are pinkish-buff in color (Baicicich and Harrison, 1997). The nestling period is 11 days, and the young are tended by both parents (Baicicich and Harrison, 1997).
MIGRATION STATUS IN WISCONSIN:
The Nashville warbler is a neotropical migrant.
NESTS AT THE LAND O' LAKES SITE:
There were four nests found at the site, two of them fledged young.
REFERENCES:
Baicicich, P.J. and Harrison, C.J.O. 1997. A Guide to the Nests, Eggs, and Nestlings of North American Birds, 2nd edition. Academic Press: San Diego.
Ehrlich, P.R., Dobkin, D.S., and Wheye, D. 1988. The Birder’s Handbook: A Field Guide to the Natural History of North American Birds. Simon and Schuster, Inc.: New York.
Stokes, D.W. and Stokes, L.Q. 1996. Field Guide to Birds: Eastern Region. Little, Brown and Co.: Boston.
