176 THE SOCIAL LIFE OF ANIMALS 



of birds is amusing, interesting and important 

 enough to warrant more attention than it is receiv- 

 ing at present. 



Studies of the sort I am going to describe were 

 initiated by a Norwegian named Schjelderup- 

 Ebbe. (108) They were made possible by the use 

 of colored leg bands and other markings by which 

 the different individuals could be recognized by a 

 human observer. Apparently the birds themselves 

 knew the individual members of the flock without 

 such artificial aids. 



Not because it is the most important work on the 

 subject, but because I can best vouch for it in de- 

 tail and in general, I shall present certain analyses 

 of group organizations that have been made in our 

 own laboratory. 



The organization of flocks of chickens is fairly 

 firmly fixed. This is particularly the case with hens. 

 The social order is indicated by the giving and re- 

 ceiving of pecks, or by reaction to threats of peck- 

 ing; and hence the social hierarchy among birds is 

 frequently referred to as the peck-order. 



When two chickens meet for the first time there 

 is either a fight or one gives way without fighting. 

 If one of the two is immature while the other is 

 fully developed, the older bird usually dominates. 

 Thereafter when these two meet the one which has 



