40 
U. S. P. R. R. EXP. AND SURVEYS-ROUTE TO CALIFORNIA. 
DENDROICA AESTIVA, G m e 1 i n .-Yellow-Poll Wood Warbler. 
Sylvicola aestiva, Rich. & $w. F. Bor. Am. vol. II, p. 211.— Aud. B. of A. Oct. vol. II, p. 50, pi. 83. 
Dendroica aestiva, Baird, Gen. Rep. IX, 232. 
Abundant over tbe entire country. 
DENDROICA NIGRESCENS, Towns .—Black-throated Gray Warbler. 
Sylvicola nigrescens, Aud. B. of A. Oct. Vol. II, p. 62, pi. 114. 
Sylvia nigrescens, Aud. Fol. pi. 395.— Townsend, Jour. Acad. N. Scien. Phil. vol. VII, p. 191. 
Sylvia Italseyii, G. P. Giraud, 16 New Species of N. A. Birds, fig. 1. 
Dendroica nigrescens, Baird, Gen Rep. IX, 270. 
I obtained, in 1852, a few specimens of this species near Sacramento City and also on the range 
of mountains which divide the Calaveras and Mokelumne rivers. During this expedition, 
in the month of October, I met with but a single individual in the mountains adjoining the 
summit of the Tejon Pass. It was then migrating southward with several other small species 
of birds and gleaning its insectivorus food from the topmost branches of some tall oaks. The 
notes of this bird closely resemble those of a locust. 
TRICHAS TOLMIEII, Towns.—Tolmie’s Warbler. 
Irichas macgillivrayii, Aud. B. of A. Oct. vol. II p. 74, pi. 100. 
Sylvia tolmieii, Towns. Jour. Acad. N. Scien. Phil. vol. VIII, p. 149_ Ib. Townsend’s Narrative, p. 343. 
Geothlypis macgillivrayi, Baird, Gen. Rep. IX, 244. 
A beautiful and somewhat rare species, affording but few opportunities for the study of its 
habits, as it retires amidst the deep shady swamps and brushwood, from whence it seldom makes 
its appearance. 
TRICHAS DELAFIELDII, Aud .—Delafield’s Yellow-throat. 
Trichas delafieldii, Aud. B. of A. Oct. vol. II, p. 81, pi. 103 .—Ib. Synop. p. 65. 
Sylvia delafieldii, Aud. Oru Biog. vol. V, p. 307. 
Geothlypis trichas, Baird, Gen. Rep. IX, 241. 
Abundant and like its closely allied species, the Trichas marilandicus , haunts the low thickets 
in the vicinity of water, in which localities it seeks its food on the ground, seldom appearing 
above the tops of the bushes. It incubates in the country, for though I was not fortunate 
enough to discover its nest, I shot on several occasions the bird in its young plumage. 
IIELMINTHOPHAGA CELATA, Say.—Orange-crowned Warbler. 
Htlinaia celaia, Aud. B. of A. Oct. vol. II, p. 100, pi. 112. 
Sylvia ceLata, Aud. B. A. Fol. pi. 178.—Bonap. Am. Orn. vol. I, p. 45, pi. 5, fig. 2. — Say, Long’s Esped. to Rocky 
Mts. vol. I, p. 169.— Nutt. Orn. vol. 1, p. 413. 
Helminthophaga celaia, Baird, Gen. Report IX, 257. 
This bird is plentiful all over the country, having procured it in northern California, in the 
Tejon valley, and on the Colorado river, near Fort Yuma. It is migratory in its habits, but 
some few pairs incubate near the summits of the highest mountains in the mining regions. 
CERTHIA AMERICANA, Bon.—Brown Tree Creeper. 
Certhia Jamiliaris, Wils. Am. Orn. vol. I, p. 122, pi. 8, fig. 1.— Aud. B. of A. Oct. vol. II, p. 109, pi. 115.— Ib. Fol. 
pi. 415. 
Certhia americana, Bonap. Compar. List. p. 11.— Baird, Gen. Rep. IX, 372. 
Abundant in California, especially in the mountainous districts. 
