Its true song, heard only in spring, consists of two or three loud sweet whistles, sometimes slurred, followed by several continuous notes, resembling chir-r-r, in a wiry but clear tone. Their notes are of great power for the size of the bird. It also has another and quite different song, which Dr. Coues thought greatly resembled the notes of the common American Redstart.
As all the birds he noticed had mated by the first of May, he has no doubt that they raise two broods in a season; and the fact that he found newly fledged young as late as the middle of August seems to corroborate the correctness of his supposition. In regard to the eggs, nest, or breeding-habits of this species, we have as yet no information.
Dendroica pennsylvanica, Baird.
CHESTNUT-SIDED WARBLER.
Motacilla pennsylvanica, Linn. Syst. Nat. I, 1766, 333, No. 19. Gmelin. Sylvia p. Lath.; Wilson, I, pl. xiv, fig. 5. Dendroica p. Baird, Birds N. Am. 1858, 279; Rev. 191.—Sclater & Salvin, Ibis, 1859, 11; 1860, 273 (Coban, Guat.; November).—Samuels, 231. Sylvia icterocephala, Lath. Ind. Orn. II, 1790, 538.—Vieill.; Bon.; Aud. Orn. Biog. I, pl. lix. Sylvicola ict. Swains.; Jard.; Aud. Birds Am. II, pl. lxxxi. Dendroica ict. Sclater, P. Z. S. 1859, 363 (Xalapa), 373 (Oaxaca).
Other localities: Bahamas, Bryant, Pr. Bost. Soc. VII, 1859. Costa Rica, Cab. Jour. 1860, 328. Panama, winter, Lawr., Ann. N. Y. Lyc. 1861, 322. Yucatan, Lawr. Veragua, Salv.
Sp. Char. Male. Upper parts streaked with black and pale bluish-gray, which becomes nearly white on the forepart of the back; the middle of the back glossed with greenish-yellow. The crown is continuous yellow, bordered by a frontal and superciliary band, and behind by a square spot of white. Loral region black, sending off a line over the eye, and another below it. Ear-coverts and lower eyelid and entire under parts pure white, a purplish-chestnut stripe starting on each side in a line with the black mustache, and extending back to the thighs. Wing and tail-feathers dark brown, edged with bluish-gray, except the secondaries and tertials, which are bordered with light yellowish-green. The shoulders with two greenish-white bands. Three outer tail-feathers with white patches near the end of the inner webs.
Female like the male, except that the upper parts are yellowish-green, streaked with black; the black mustache scarcely appreciable. Length, 5.00; wing, 2.50; tail, 2.20.
Hab. Eastern Province of the United States; Bahamas; Guatemala to Costa Rica and Panama R. R. Not recorded from Mexico proper or West Indies, except Bahamas.
The young in autumn is very different from either male or female in spring. The entire upper parts are of a continuous light olive-green; the under parts white; the sides of the head, neck, and breast ash-gray, shading insensibly into and tingeing the white of the chin and throat. No black streaks are visible above or on the cheeks, and the eye is surrounded by a continuous ring of white not seen in spring. In this plumage it has frequently been considered as a distinct species.