676 Field Museum of Natural History — Zoology, Vol. IX. 



Adult female: Similar to the adult male, but usually (not always 

 with black cap on crown more restricted and more or less obscured 

 by the feathers being tipped with olive. In some adult females the 

 black is entirely absent, the crown being olive green like the back. 



Immature: Similar, but without the black cap. 



The plumage of adults in fall and winter apparently varies but 

 little from that of spring. 



Length, 4.80; wing, 2.25; tail, 2; bill, .32. 



Wilson's Warbler occurs more or less commonly as a migrant in 

 spring and fall in Illinois and Wisconsin, and according to Messrs. 

 Kumlien and HoUister, a few remain to breed in the northern part of 

 the latter state. They say: "A common migrant in southern Wis- 

 consin, passing northward late, often as late as the first week of June. 

 Undoubtedly a few nest in Wisconsin, even as far south as Jefferson 

 County, although there is no actual record. Specimens have been 

 taken near Jefferson, June 16. Young birds are often taken as early 

 as the middle of August in the large tamarack swamps. Principally 

 a frequenter of low lands, and willowy thickets, often in tamarack 

 swamps." (Birds of Wisconsin, 1903, p. iig.) 



336. Wilsonia canadensis (Linn.). 



Canadian Warbler. 



Sylvania canadensis (Linn.), A. O. U. Check List, 1895, p. 286. 

 Distr.: Eastern North America, west to the Plains and north to 

 southern Labrador, northern Quebec, and Athabaska; breeds from 

 Alleghany Mountains, southern New England, Wisconsin, and Michi- 

 gan northward; south in winter to Central America and northern 

 South America. 



Adult: Upper parts, ash-gray; forehead and crown, black; most 

 of the crown feathers edged with gray, producing a streaked appear- 

 ance; eye ring, yellowish or yellowish 

 white ; a short yellow superciliary stripe 

 extending to base of bill; an irregular 

 black streak from below the eye, "ex- 

 tending on sides of neck; throat and 

 under parts, yellow, the breast marked 

 with a band of irregular short black 

 streaks or dashes; wings and tail, plain 

 brownish gray, without white spots; 

 under tail coverts, white. 



Adult female: Similar, but black on head restricted to a few small 



