Xll 



nests have been carefully studied as to elements of 

 composition and peri6ds of building; and many- 



pairs of the species whose habits are herein des- 

 cribed, have been closely and diligently watched, 

 with the view of determining the details of incu- 



O 



bation, and the early history of the young. The 

 various articles which cqntribute to their main- 

 tenance have been partially derived from repeated 

 observations upon the same species in their 

 natural haunts, and elsewhere; but mainly from 

 examinations of the stomachs of more than seven 

 hundred birds. 



A brief synopsis of the leading items of interest 

 embraced within its scope, cannot be amiss. 

 Herein are found numerous facts which an- un- 

 mentipned in the latest American work on birds, 

 besides corrobo rations of important statements of 

 Audubon and \Yilson which have been entirely 

 i-noivd by its authors. In addition to which, a vast 

 amount of knowledge which has not hitherto been 



* * 



published, ind which may be conveniently ar- 



r:in .1 under the lollowm--*' heads 



._> 



1. Descriptions of nests which show marked 

 deviations irorn normal structures, and the causes 

 \vhich have probably conduced to the -variations 



2. Labor of nidification whether performed by 

 the ivale and female separately, or conjointly. 



