Comparative Periods of Nestling Life 



15 



days, an acciiniiilatiou of dirt made it certain that the 

 ■ birds had been working, probably in enhirging the end of 

 the hole for the nest. With a nesting cycle of from two 

 and one-half to three months, this species can hardly be 

 other than single brooded. 



Again to show the fine detailed work of some of our 

 observers, I have assembled a table exhibiting day by day 

 the increase in weight (in grams) of some nestlings taken 

 in 1906 by the late John F. Ferry, Lake Forest, 111. The 

 Cedar Waxwing study (Aug. 20-28) is incomplete, but the 

 development and length of nestling life of the Cowbird 

 (June 11-22), Yellow Warbler (June 21- July 2) and Wood 

 Thrush (June 11-22), exhibit a relatively slower growth, 

 considering size, than the Catbird (June 13-21) and the 

 Brown Thrasher (July 8-lJJ). 



* Found dead. ** Departed. 



[to be continued] 



