behavior in the excreta removal. Thus, we may explain the ap- 

 parently unique behavior of the birds in promptly removing the 

 foreign bodies, such as bits of paper, as a modification of a well- 

 developed instinct of removing the excreta from the nest; and 

 which is adaptive, but not purposeful. 



May we not also explain the behavior of birds toward a foreign 

 egg in the same way? May we not consider the Cowbird's egg 

 to be a foreign body, merely, to the imposed-upon parents? And 

 it is not only unnecessary^ but unwarranted to assume that the 

 foster parents have any knowledge of the potential capacity of 

 this egg to hatch, or to have any conscious knowledge of the past 

 experience by which they may draw judgments? Are the facts 

 of this behavior not sufficiently explained in t^rms of reflex 

 action, as suggested above? 



The capacity for intelligent action, or the actual occurrence of 

 it in birds under other circumstances is not denied or discussed 

 here. 



During the season of 1916 Professor B. Shimek, Director of 

 the Iowa Lakeside Laboratory, generously placed at my disposal 

 the facilities of this institution, and I appreciate the many cour- 

 tesies and kindnesses extended to me. 



37 



