148 THE CHESTNUT-SIDED WARBLER. 



the breast pulsing with the earnestness of expression. It is not easy to recog- 

 nize amid tlie May medley of song. 



The nest is lashed upon a horizontal branch, or bound into a horizontal 

 fork, well out from the tree, and always well up from the ground.* Two nests 

 which I have found in the famous South Woods were in a beech and rock 

 maple tree respectively, one thirty, the other sixty feet from the ground. These 

 nests resemble the nest of Redstart more than the nest of any other bird, both 

 in composition and construction, but they were stuccoed with cobwebs out- 

 wardly. The material was mostly shreds of bark and horse-hair, with a little 

 milkweed bark. The birds are very solicitous for their nest and young, utter- 

 ing the sharp chip of alarm and distress, and venturing within a few feet of 

 the intruder, but they do not show a disposition to fight. I have found nests 

 only near small streams in the woods, or depressions where temporary 

 streams form after severe rains or in spring. 



The eggs are hardly distinguishable from other warblers' eggs. The 

 markings incline to darker, or to less reddish in the browns. Four is the usual 

 number for a complete set. It appears that this warbler builds too high for 

 the Cowbird, or else the nest is too small to accommodate the sneaking 

 creature. Lynds Tones. 



No. 66. 



CHESTNUT-SIDED WARBLER. 



A. O. U. No. 659. Dendroica pensylvanica (Linn.). 



Description. — Adult male : Extreme forehead ashy white ; crown bright 

 yellow (gamboge); hind neck streaked black and ashy white; back and rump 

 bright olive-green, with partially concealed black stripes ; upper tail-coverts black, 

 edged with ashy and olive ; wings and tail black, primaries and rectrices edged 

 with ashy ; secondaries and tertials edged with yellowish green ; two irregular 

 wing-bars light yellow ; three outer pairs of tail-feathers extensively white on 

 inner webs ; a black patch on the side of the head including eye ; an irregular 

 white patch behind this; below white; sides of breast and sides with large chest- 

 nut patches, irregular or interrupted; bill black; feet dark. Adult female: Like 

 male but duller; chestnut of sides much restricted; black face blotch divided by 

 ashy, etc. No autumnal change in either sex. Immature : Quite different ; 

 above bright olive-green ; below ashy or sordid white ; wing-bars and tail-blotches 

 as in adult; rectrices in unworn plumage quite acute; bill light below. Length 

 4.75-5.25 (120. 6-133. 3) ; av. of six Columbus speciments: wing 2.36 (59.9) ; tail 

 1.91 (48.5); bill .36 (9.1). 



Recognition Marks. — Smaller; white under parts and chestnut sides of 

 adult; light yellow wing-bars of young. 



