194 USEFUL BIRDS. 



The food of the Chestnut-sided Warbler is such that the 

 bird must be exceedingly useful in woodland and shrubbery, 

 and in orchard and shade trees as well, whenever it frequents 

 them. It is probable that at times it destroys considerable 

 numbers of parasitic hymenoptera, as it is rather expert as a 

 flycatcher ; but it is very destructive to many injurious beetles 

 and caterpillars, being one of the most active consumers of 

 leaf-eating insects. Small borers or bark beetles, plant bugs 

 and plant lice, leaf hoppers, ants, and aphids are eaten. 



In seasons of great want it eats a few seeds. Audubon 

 says that he once shot several birds in Pennsylvania during a 

 cold spell and snowstorm in early spring, and that the only 

 food in their stomachs was grass seeds and a few spiders, but 

 the birds were emaciated and evidently half starved. This 

 Warbler is almost entirely insectivorous, and for this reason, 

 perhaps, as soon as its young are well able to travel both 

 young and old begin their southern journey. In September 

 a few birds, probably from farther north, may be seen in 

 autumnal dress, gleaning insects from the tree tops, and no 

 more are seen until the following spring. 



Yellow Warbler. Blue-eyed Yellow Warbler. Yellow Bird. Summer 

 Yellow Bird. "Wild Canary." 



Dendroica aistiva. 

 Length. — About rive inches. 

 Adult Male. — Yellow; "back a rich yellow-olive, occasionally streaked with 



orange-brown ; breast also streaked narrowly with the same color. 

 Adult Female. — Similar, but duller ; breast generally unstreaked. 

 Nest. — A deep, soft cup five to ten feet from ground, in a bush, or higher up in 



orchard or shade tree, or in a fork of small sapling or shrub. 

 Eggs. — Either bluish-white or greenish- white, with obscure lilac markings, and 



brown spots grouped around the larger end. 

 Season. — May to September. 



The Yellow Bird is the most familiar of all our Warblers, 

 for it has forsaken the woodlands for orchards and shade 

 trees near dwelling houses. It arrives in May, when the first 

 young leaflets begin to clothe the trees with verdure, and 

 plays about like a rich yellow flame among the pink of the 

 apple blossoms. It is often confused in the popular mind 

 with the Goldfinch, which is also called the Yellow Bird, 

 but which may be distinguished at once by the black of the 



