OF EASTERN PENNSYLVANIA. 137 



surroundings are favorable, and birds already 

 paired have been noticed under the most sus- 

 picious circumstances. 



Nidification occurs most probably about the 

 1 5th of May, as Mr. Nuttall describes a nest 

 which he observed with a full complement of eggs, 

 highly advanced towards hatching, on the yth of 

 June, which was built about forty feet from the 

 ground, wedged in between two nearly vertical 

 branches of a Virginia juniper tree, in Mt. Auburn. 

 This fabric was composed principally of the wiry 

 stems of Polygonum tenue, circularly interlaced with 

 caterpillars' webs, and linty fibres of Asclepias. 

 Interiorly, there were noticed fine rootlets, a few 

 bristles, down of fern-stalks, and feathers. Several 

 nests were discovered by Mr. Nuttall of similar 

 manufacture. 



Several nests of this Warbler found by George 

 O. Welch, Esq., in Lynn, Mass., differed from the 

 one just described, only in the composing 

 materials. These were built of red cedar bark, 

 the liber of several deciduous trees, dry grasses, 

 and plant-stems, and the exuviae of insects; in- 

 ternally, with feathers, silk of plants, and fur of 

 small mammals, lining comparatively large and 

 deep cavities. There were also some wiry roots 

 noticeable. They measured two and a half inches 

 in height, and three in diameter. 



In Massachusetts but a single brood is reared 

 in a season, whereas at the south it is accredited 

 with being triple-brooded. 



