Chestnut-sided Warbler— A Study 209 



Be warned to keep from a Chestnut-sided Warbler's nest after the young 

 birds are a few days old, for .hex seem m possess an unusual nervous irritability 

 and gain the fear instinct at an unusually early period. They luvo.no frantic 

 al any disturbance, even when the feathers extend from their tnl.es so little that 



the birds seem covered with minute camel's hair brushes, a. a time when most 



nestlings have an undisturbed, dignified manner because knowing nothing of 



tear. They leap from the nesi and even if caught and returned are likely to refuse 



to stay. Perhaps all Chestnut-sided Warblers do not gain the fear instinct as 

 early as did those oi three broods observed (instead of only one to three days 

 before flight). Hut if they do. it would seem that here natural selection has a 

 handle by which to keep the ranks of this species well reduced. 



ROSE-BREASTED GROSBEAK \.\n WEST 

 Photographed by V. V. in. we. Sterling, III. 



