292 PROCEEDINGS OF THE ACADEMY OF 



OBSERVATIONS ON NESTS OF SAYORNIS FUSCTJS. 

 BY THOS. 0. GENTRY. 



It is the commonly received opinion that birds of the same 

 sjDecies uniformly- build their nests of the same materials and in 

 the same form and situation though they inhabit different climates. 

 This, however, is not invariably the case, as a few observations 

 will show. On the north branch of the Susquehanna, some 

 months since, I procured several nests of oiir common Phebe 

 bird, Sayornis fusciis, Baird, which in size, structure, and ma- 

 terials mUrht be taken as nests of species distinct from the one 

 under consideration. As these nests were found upon the hori- 

 zontal beams of a wagon-shed they would not seem to require 

 such compactness of structure as when built in more exposed 

 situations. 



After a careful examination of several nests from different 

 localities, I find that they are usually circular at the top, with a 

 depth externally, differing but little from the average diameter. 

 By measurement I obtain the following dimensions: Diameter 

 from side to side, 3^ in., depth 3 in. ; diameter of cavity within, 

 2^ in., making the thickness of the lateral walls ^ in.; depth of 

 cavity l^ in., indicating a thickness at the bottom of l^ in. These 

 nests are composed of fine roots, grasses, fine mosses, and hairs, 

 which are plastered together, and to the objects upon which they 

 are built, by pellets of mud ; within they are lined with soft grasses, 

 lint, hairs, and sometimes with wool and feathers. 



Number one of deviation is nearly circular, with an average 

 diameter of 4 in. and a depth of 2 in., being considerably de- 

 pressed. Diameter of cavity 2iin., depth 1 in.; thickness of lateral 

 walls I in.; at the bottom 1 in. The nest is constructed wholly 

 of the silk of corn, with a few strings and hairs on the inside for 

 a lining; the absence of moss and clay pellets being a noticeable 

 feature of the nest ; such ordinarily indispensable materials evi- 

 dently not being requisite, if the site of the nest aflbrds any cri- 

 terion of judging. 



Number two of these anomalous forms is circular, with a 

 diameter of .5 in., and a depth of 2^ in. on the outside ; within 2^ 

 in. in diameter, and 2 in. in depth ; lateral walls 1^ in. in thick- 

 ness ; inferior ^ in. The entire nest is composed of the inner 



