304 KEY TO VIEEOS 



Besides being pleasing birds from their ready 

 response to our friendliness, the Vireos are of 

 great value to our trees. They may be found 

 from morning till night searching among the leafy 

 treetops for insects both in our forests and in our 

 villages and towns. They probably rank next to 

 the Cuckoo in the destruction of caterpillars, and 

 are also of great value from their fondness for 

 bugs and weevils, May beetles, inch-worms, and 

 leaf-eating beetles. 



With the Vireos we finish the tenth family 

 of Perching Birds. 



I. Flycatchers. II. Larks. III. Crows and 

 Jays. IV. Blackbirds and Orioles. V. Finches 

 and Sjtarrows. VI. Tanagers. VII. Swallows. 

 VIII. Waxwings. IX. Shrikes. X. Vireos. 



Key to Vireos. 



1. With wing bars ; upper parts bright olive-green. 



2. Throat bright yellow. 



p. 301. YELLOW-THROATED VIREO. 



2'. Throat white or whitish. Song, " Now, who are you', 

 eh?" p. 302. WHITE-EYED VIREO. 



1'. Without wing bars ; upper parts dull olive-green. 



3. Head with gray cap, bordered by black and white lines. 



Song, broken triplets . . p. 120. RED-EYED VIREO. 



3'. Head without gray cap. Song, a continuous flowing 

 warble, heard from elm-tops. 



p. 126. WARBLING VIREO. 



