448 LAND BIRDS 



to understand and translate into human speech. Mrs. 

 Eckstrom says : " Few birds are easier to tell by their 

 music and harder to tell without it than the Vireos. By 

 all means put their song into words." The song of the 

 Warbling Vireo is a quaint, cheery melody whistled all 

 day long until chill autumn rains drive him to a warmer 

 climate. He is a mountain-lover, choosing the aspens 

 and oaks of the Sierra Nevada rather than the lowland 

 thickets. If he condescends to build in a city park, his 

 nest will swing as near the top of the tallest tree as he 

 can find suitable twigs to hold it. Usually it will be at 

 the edge of a stream or near an open space. In the fall 

 this bird becomes very friendly, coming into the orchards 

 and gardens to hunt busily among the leaves for small 

 caterpillars. At this time he is fond of the cornel ber- 

 ries that grow along mountain brooks, and occasionally 

 condescends to eat mistletoe, though he prefers insect 

 food. 



629 a. CASSIN VIREO. — Lanivireo solitarius cassini. 

 Family : The Vireos. 



Length: 5.00-5*. 60. 



Adults: Top and sides of head dark gray, blending to white on the 

 throat ; clearly defined white eye-ring and loral streaks ; back dull 

 olive-green ; wings with two clear white bands ; under parts clear 

 white, tinged with yellow and olive on sides and flanks. 



Young : Upper parts dull grayish brown ; under parts dull bufFy. 



Geographical Distribution : Western United States, chiefly on the Pacific 

 coast in summer ; east to New Mexico, and south to Mexico in winter. 



California Breeding Range : Along the Sierra Nevada. 



Breeding Season : May, June, and July. 



