274 WILSON'S WARBLER 



(3) J. P. N[oi!Ris], A Series of Eggs of Myhrdwctes mtratus, Orn. and 061., 

 XII, 200. (4) A. B. Blackmore, The Hooded Warbler (in La.), Oologist, XII, 

 1895. (s) E. P. BiCKNELL, A Study of the Singing of Our Birds, Auk, I, 1884, 



2l6. 



WILSON'S Warbler 



WILSONIA PUSILLA PUSILLA (Wils.) Plate XXII 



Distinguishing Characters. — The (? and generally also the ?, may be known 

 by its black cap, entirely yellow underparts, and absence of white in the wings 

 and tail. Females in which the cap is lacking (young?) resemble the young 

 Hooded Warbler but are smaller and have no white in the tail. Length (skin), 

 4.25; wing, 2.10; tail, 2.00; bill, .32. 



Adult (S, Spring. — Crown shining black, forehead, cheeks, including line 

 over eye, bright yellow ; rest of upperparts bright olive-green ; wings and tail 

 narrowly edged with same color and without white marks ; underparts entirely 

 bright yellow ; upper mandible brownish black, lower, flesh color. 



Adult d. Fall. — Similar to adult c? in Spring but black cap narrowly tipped 

 with olive. 



Young c?, Fall. — Similar to adult c? in Fall but cap more widely tipped with 

 olive, yellow of forehead and above eye duller. 



Adult S, Spring. — Sometimes not distinguishable from adult c? in Spring 

 but usually with black cap less sharply defined and conspicuously tipped with 

 olive-green; yellow duller. In this plumage closely resembles young tS in Fall. 



Adult 2, Fall. — Similar to adult ? in Spring but crown more widely tipped 

 with olive-green. 



Young ?, Fall. — Similar to adult S in Fall, but black cap absent, or if 

 present, so broadly tipped with olive-green as to be concealed. 



Nestling. — Above hair-brown, breast lighter, belly yellowish white, the sides 

 brownish, lesser and median wing-coverts tipped with brown-tinged white 

 forming two well-marked wing-bars. 



General Distribution. — Eastern North America. 

 Summer Range. — Principally in Canada, a few nesting in northern 

 Maine (casually south to Pittsfield, Me., and accidentally at Lancaster, 

 N. H.), central Ontario (Ottawa, Madoc, Lansdowne), northern Min- 

 nesota, Manitoba and Hudson Bay region. Casual in the Rocky Moun- 

 tain region during migrations. 



Winter Range. — Mexico to Panama ; accidental once in the West 

 Indies. 



Fall Migration. — Some dates of the last one seen are at New- 

 port, Ore., August 30, 1900; Berkeley, Cal., September 17, 1888; 

 Columbia Fails, Mont., September 14, 1894; Cheyenne, Wyo., Septem- 

 ber II, 1888; Cooney, New Mex., October 9, 1889; Aweme, Man., 

 average six years September 8; Lanesboro, Minn., average of four 

 years September 20, latest September 25, 1887; Grinnell, la., average 

 four years September 21, latest September 25, 1888; Ottawa, Ont., 



