GROUP ORGANIZATION 179 



Then a triangle was encountered in which M pecked 

 Y, Y pecked YY and YY pecked M; and each of these 

 had the peck-right over the remaining members of 

 the flock. 



Such irregularities are by no means uncommon 

 even in well-established flocks. A hen which is 

 otherwise the alpha bird in the pen may be pecked 

 with impunity by some low-ranking member, al- 

 though the latter is in turn pecked by many birds 

 over which the alpha hen has a clearly established 

 social superiority. This inconsistency may result 

 from the low-ranking bird having first met the 

 alpha bird on one of its off days, gained the advan- 

 tage in the first combat and managed to keep it 

 thereafter with the aid of the psychological domi- 

 nance thus established. 



Similar social hierarchies exist also among flocks 

 of male birds. One flock of cockerels, which we 

 studied for seventy days, demonstrated the social 

 order shown in Figure 40 in which there are six 

 triangle situations that run through all the upper 

 part of the social scale, but are especially evident in 

 the middle ranks where B is involved in four of 

 them. 



Cockerels are more pugnacious than pullets, even 

 when they are kept, as these were, on a diet which 

 somewhat restricts the tendency to fight. There were 



