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BULLETIN 1355, TJ. S. DEPARTMENT OF AGEICULTUKE 



When the mating season arrives, from the middle of May to the 

 last of June, the nest is started in a convenient fork of a branch, often 

 near the ground; and, when finished, this is suspended by the rim 

 rather than supported from below. The nest is a trim aflfair, about 

 the size of a small teacup, woven of fibrous matter, among which 

 may be instanced such substances as bits of birch bark, grapevine 

 bark, or flax. Diligent search is required to disclose a nest when the 

 leaves are green, but the number visible in fall is surprising. The first 

 egg may be laid even before the nest is finished, and when this is the 

 case the female remains at the nest while her niate searches for 

 additional building materials. During the season of rearing the 

 young, the patience of the red-eye is taxed to the utmost by the cow- 

 bird. Brewer has reported a case of this form of parasitism where 

 the vireos reared three young cowbirds without laying eggs of their 

 own, and other records show that one or two cowbirds' eggs are not 

 uncommonly found in a vireo nest. 





Fig. 2. — Monthly proportions of the various items in the food of the red-eyed vireo ( Vireosylva olivacea) > 

 based on the analysis of the contents of 569 stomachs, with the average of each item for the year 



The annual food of the red-eyed vireo is composed of 85.28 per 

 cent animal matter and 14.72 per cent vegetable. (See fig. 2.) The 

 vegetable matter is taken more often late in summer and in fall and 

 consists of the berries and fruits of such plants as wild cherry, sassa- 

 fras, cornel (or dogwood), wild grapes, and woodbine. Of a total of 

 653 stomachs available, 569 contained sufficient food for the correct 

 estimation of percentages, and it is on the examination of the latter 

 that the present report is based. This material was collected during 

 the months April to October, inclusive, over the greater part of the 

 range of the species in North America. 



