468 Birds of Colorado 



medley of calls and whistles, and are very often heard 

 at night, especially if it is moonlight. 



The nest is placed among small saplings or briers at 

 from two to three feet above the ground ; it is constructed 

 of leaves and grasses, and has as a rule no special hning. 

 The eggs, usually four, are clear white with spots and 

 specks, or sometimes large blotches of various shades 

 of brown, and measure about "86 x '66. Fresh eggs 

 should be met mth about the second week in June near 

 Denver, according to Dille. 



Genus WILSONIA. 



Small fly-catching Warblers with a very short, broad and flattened 

 bill, distinctly wider than deep at the nostrils ; rictal bristles con- 

 spicuous ; wing with the ninth (outer) primary longer than the flfth, 

 the sixth to eighth the longest ; tail shorter than the wing and somewhat 

 rounded ; plumage chiefly yellow and green, no red. 



Three species, all breeding in the United States. 



For key, see p. 439. 



Pileolated Warbler. Wilsonia pusilla pileolata. 



A.O.U. Checklist no 685a — Colorado Records — Allen 72, pp. 156, 

 162 ; Aiken 72, p. 197 ; Trippe 74, p. 232 ; Henshaw 75, p. 207 ; Minot 

 80, p. 228 ; Tresz 81, p. 286 ; Allen & Brewster 83, p. 159 ; Stone 84, 

 p. 20 ; Drew 85, p. 15 ; Beckham 87, p. 123 ; Morrison 88, p. 72 ; Lowe 

 94, p. 269 ; McGregor 97, p. 39 ; Cooke 97, pp. 19, 117, 228 ; 04, p. 128 ; 

 Keyser 02, pp. 63, 238 ; Henderson 03, p. 108 ; 09, p. 240 ; Warren 

 06, p. 24 ; Gibnan 07, p. 194 ; Chapman 07, p. 278 ; Rockwell 08, p. 177. 



Description. — Male— Crown glossy black, forehead, eyebrow and 

 cheeks very bright yellow ; above olive-green, dusky on the wings 

 and tail ; below bright yellow throughout ; iris brown, bill dusky- 

 brown, paler on the lower mandible, feet light brown. Length 4-5 ; 

 wing 2-25 ; tail 20 ; culmen -30 ; tarsus -75. 



The female resembles the male, but is usually duller in colour, and 

 the black crown-patch is less glossy and smaller. The male in the 

 autumn is very similar, and the young bird has even less trace of the 

 black cap. 



Distribution. — The species is found breeding throughout western 

 North America from Alaska to western Texas, but only at considerable 

 elevations towards the south. It winters throughout the greater 

 part of Mexico, and as far south as Panama. 



