NORTH AMERICAN BIRDS. 371 



contained three eggs of the Warbler and one of the Cowbird ; sizes, 

 .64X.50, .63x49, .64X.50. 



659. Dendroica pensylvanica (Linn) [99.] 



Chestnut-sided "Warbler. 



Hab. Eastern United States and Canada. Breeds north of 40^ except in higher mountain ranges. In 

 winter, south to Bahamas, Eastern Mexico, and Central America to Panama. 



This well-known Warbler breeds abundantly in the Middle and 

 Northern States within its range. Mr. Mcllwraith gives it as a com- 

 mon resident of Ontario, breeding in suitable places near Hamilton 

 and throughout the country, raising two broods in a season. Breeds, 

 but not commonly, in Central Ohio, more abundant in the northern 

 portion. Nests in the latter part of May and in June. 



The nest is commonly built in a low bush, shrub or sapling from 

 two to eight feet above the ground. The situations chosen are the 

 " scrub-lands " or open woods in low grounds, with a growth of bushes, 

 vines, etc. The nest is generally coarser than the Yellow Warbler's, 

 and contains fewer woolly materials. It is composed of narrow strips 

 of thin bark or dried grasses, mixed with plant-down, fine bleached 

 grasses, and lined with hairs. 



The eggs are four, rarely five, in number, and vary from clear- 

 white to creamy-white in ground-color, speckled with rusty-brown and 

 chestnut, often tinged with lilac -gray, chiefly at the larger end, where 

 they frequently form wreaths. A set of four offers the following sizes: 

 .68X..50, .65X.47, .67X.49, .68X.49; average .68X.50. Eggs of the 

 Cowbird are commonly found in nests of this species. 



660. Dendroica castanea (Wils.) [100.] 



Bay-breasted "Warbler. 



Hab. Eastern North America. Breeds from Northern New England and Northern Michigan north- 

 ward to Hudson Bay; south in winter through Eastern Mexico and Central America. 



The Bay-breasted Warbler is known to breed from Northern New 

 England and Northern Michigan northward. Mr. William L,. Kells 

 found it breeding in the vicinity of Listowel, Ontario, in low, swampy 

 woods, where there is a mixture of evergreens, ash, birch, elm and other 

 trees. 



The nests are compact, cup-shaped structures, usually placed 

 in coniferous trees from five to fifteen or even twenty feet 

 above the ground. Mr. Kells found a nest placed between a slender 

 limb and the trunk of a small cedar about five feet up ; another was 

 found in a hemlock at an elevation of fourteen feet. The nest is com- 

 posed of fine shreds of bark, small twigs, fibrous roots and pine 

 hair ; the interior is a little more than two inches in diameter by one 

 in depth. 



