434 Birds of Colorado 



primary obvious, longer than the coverts ; iris brown, bill pale 

 horn, legs dmky. Length 4-90 ; wing 2-90 ; tail 2-2 ; culmen -40 ; 

 tarsus -75. 



The sexes are alike ; the young bird has the top of the head bufEy, 

 and buSy tips to some of the coverts. 



Distribution. — Breeding in western North America from British 

 Columbia and Athabasca south along the eastern border of the Rocky 

 Mountains to New Mexico and Lower California ; further south in 

 winter to Vera Cruz and Oaxaca in Mexico. 



In Colorado this species is the commonest of the Vireos, arriving 

 from the south about the middle of May in El Paso co., and spreading 

 up into the mountains, where it breeds up to about 10,000 feet. The 

 earliest date for El Paso co. is May 15th among the Aiken collection, 

 but Warren gives May 3rd for Baca co., and Henshaw the same date 

 for Fort Garland. Other recorded localities are Loveland, May 12th, 

 W. G. Smith (Cooke), Boulder co. (Miiiot), Limon (Aiken), and Pueblo 

 (Beckham), in the plains and foothills ; in the mountains, Estes 

 Park (Kellogg), Graymont, 10,000 feet (Keyser), Breckenridge (Carter 

 apud Cooke), Twin Lakes (Scott), South Park (Allen), Mesa co., 

 common, breedmg at 7,500 feet (Rockwell), San Juan co. (Drew) and 

 La Plata co. (Gilman). 



Habits. — ^The Warbling Vireo frequents deciduous trees, 

 especially cotton-woods and aspens, and also groves 

 and orchards about the dwelling-places of man. They 

 are celebrated for the sweetness of their song, their notes 

 being soft, low and musical ; according to Keyser they 

 sing even while sitting on the nest. They are of great 

 service to man as insect destroyers, devouring large 

 numbers of scale and other insects injurious to fruit 

 and shade trees. 



The nest, hke that of the Red-eyed, is suspended to 

 the slender forks of twigs either of a cotton-wood or at 

 great elevations of a quaking aspen ; it is somewhat 

 smoother and more compact in its make-up. The eggs, 

 four to five in number, are white, sparmgly spotted 

 about the larger end with reddish to dark brown and 

 lilac. They measure about '75 x 55. Fresh eggs 

 may be looked for about July 1st. 



