276 IT. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



DENDROICA CASTANEA, B a i r d . 



Bay Breasted Warbler. 



Sylvia casliinea, Wilson, Am. Cm. IF, 1810, 97; pi. x\v, f. 4— Bonap. Obs. Wils. 1826, \o. 139.— Nuttai.i,, Man. 



I, 1832, 382.— Audubon, Orn. Biog. 1, lf-33, 358; pi. 69. 

 Sylvicola castmtFM, " Swainson," Jard. ed. Wilson, 1832.— Rich. List, 1837. — Bon. List, 1838. — Ib. Consp. 1850, 



308.— Add. Syn. IS.SS, 53.— Ib. Birds Amer. II, 1841,34 ; pi. 80. 

 Rhiinanphus castaneus, Cab. Miis. Hein. 1850, 19. 



Sylvia ou(u»ina(is, AVii.son, Am. Orn. Ill, 1811, 65 ; pi. .x.\iii, f. 3.— Bon. Obs. 1826, No. 152.— Aun. Orn. Biog. I, 

 1832, 447; pi. 88 — Nuttall, Man. I, 1832, 390. (Female or young in autumn.) 



Sp. Cii. — Male. Crown dark reddish chestnut ; forehead and cheeks, including a space above the eye, black ; a patch of buff 

 yellow behind the cheeks. Rest of upper parts bluish gray streaked with black, the edges of the interscapulars tinged with 

 yellowish, of the scapulars with olivaceous. Primaries and tail feathers edged externally with bluish gray; the extreme cuter 

 ones with white ; the secondaries edged with olivaceous. Two bands on the wing and the edges of the tertials white. The 

 under parts are whitish with a tinge of buff , the chin, throat, fore part of breast, and the sides, chestnut brown, lighter than 

 the crown. Two outer tail feathers with a patch of white on the inner web near the end ; the others edged internally with 

 the same. Female with the upper parts olive, streaked throughout with black, and an occasional tinge of chestnut on the 

 erown. Lower parts with traces of chestnut, but no stripes. Length of male, 5.00; wing, 3.05; tail, 2.40. 



Hnb. — Eastern United States to the Missouri. South to Guatemala. 



The female appears not to be very constant in her markings ; sometimes the trace of chestnut 

 on the crown is conspicuous ; sometimes it is entirely wanting. The extent, too, of the chest- 

 nut beneath is subject to considerable variation. 



In the young bird and possibly in the adult in autumn, the upper parts and sides of the head 

 and neck are of a bright though light olive green, obsoletely streaked with black, chiefly in the 

 middle of the back, the rump with an ashy tinge. Beneath buff white, the sides tinged with 

 brown, sometimes showing a trace of the chestnut of spring. Sometimes there is a greenish 

 yellow tinge on the throat and breast. There is a pale line over the eye, and the eyelids are 

 yellowish, the eye cut by a faint dusky bar from the base of the bill. 



This species is in many respects very closely allied to D. striata, and although the adults in 

 spring are readily distinguishable, it becomes very difficult to separate them when in autumnal 

 or immature plumage. They are of about the same size ; the upper parts would be almost 

 jirecisely the same, if the chestnut crown of B. castanea were replaced by black ; the back of 

 1 he neck in striata is streaked with white, and the back has a less yellow tinge. The females 

 are still more similar above. The absence of streaks, however, on the under parts of S. castanea 

 would separate them in all cases, but for the fact that these sometimes are obsolete in young of 

 D. striata. The bill of D. castanea is broader at the base and more bristled ; the tails are 

 almost precisely the same ; the inner borders of the quills of D. castanea are abruptly pure 

 white, instead of gradually becoming lighter, as in the other. 



A careful comparison of an extensive series of immature specimens of the two species shows 

 that in castanea the under parts are seldom washed uniformly_on the throat and breast, with 

 yellowish green ; but while this may be seen on the sides of the neck and breast, or even across 

 the latter, the chin and throat are nearly white, the sides tinged with dirty brown, even if the 

 (generally present) trace of chestnut be wanting on the sides. There is a buff tinge to the 

 under tail coverts ; the ([uills are abruptly margined with white, and there are no traces (how- 

 ever obsolete) of streaks on the breast. In D. striata the under parts are quite uniformly 

 washed with greenish yellow nearly as far back as the vent, the sides of tlie breast and some- 

 times of belly with obsolete streaks ; no trace of tlie uniform dirty reddish brown on the si(l( s 



