278 PILEOLATED WARBLER 



PlLEOLATED WARLBER 



WILSONIA PUSILLA PILEOLATA (Pallas) 



Subspecific Characters. — Similar to Wilsonia p. pusilla but forehead 

 much more intense, orange rather than yellow; olive-green of back and yellow 

 of underparts deeper, richer; averages slightly larger. 



As with Helminthophila celata orestera, the Rocky Mountain bird, while 

 intermediate in color between Atlantic and Pacific coast specimens, is slightly 

 larger than either. Wing, 2.25; tail, 2.00; bill, .35. 



General Distribution. — Rocky Mountain region. 



Summer Range. — Breeding throughout the Rocky Mountain dis- 

 trict, from western Texas (Chisos Mountains), New Mexico (?) and 

 Arizona ( ?) in higher mountains, northward to Alaska, including coast 

 district (Kadiak, Yakutat, Sitka, etc.) as well as throughout the in- 

 terior, westward to eastern Oregon (Fort Kalmath; Tillamook) and 

 Queen Charlotte Islands, British Columbia; during migration over the 

 whole of western North America (less commonly along the Pacific 

 coast of United States) and eastward across the Great Plains to Min- 

 nesota (Fort Snelling, May), western Missouri (Independence), etc. 



Winter Range. — Southward over whole of Mexico and Central 

 America to Chiriqui (Boquete). (Ridgw.) 



The Bird and its Haunts. — In Colorado, Cooke 3 writes, this bird 

 reaches its summer home just above timber-line by the end of June 

 and is then the most numerous insect-eating bird at that altitude. The 

 center of abundance during the breeding season is about 11,000 feet, 

 but it has been known to breed from 6,000 to 12,000 feet. 



In Alaska, Nelson 2 states that this Warbler is "one of the com- 

 monest of the bush-frequenting species in the north and extends its 

 breeding range to the shores of the Arctic Ocean, where it is found 

 breeding about Kotzebue Sound as well as along the eastern coast of 

 Norton Sound wherever shelter is afforded." 



Song. — "Song, Chee-chee-chee-chee (or this syllable repeated 

 seven times), thus different from their song as I recall it in the East. 

 Certain low querulous notes are indescribable." (Minot 1 ). 



Nesting Site. — A nest found June 22, near Seven Lakes, Colo- 

 rado, by Minot 1 "was sunken in the ground on the eastern slope or 

 border of the swamp, at the end of a partly natural archway of long, 

 dry grass, opening to the southward, beneath the low, spreading 

 branch of a willow." 



Nest. — The nest above mentioned is described as "composed of 

 loose shreds, with a neat lining of fine stalks and a few hairs, and 

 with a hollow two inches wide and scarcely half as deep." 



