112 



THE SOCIAL LIFE OF ANIMALS 



this time the gull chicks that wander from their home 

 nests may be pecked to death by other members of 

 the colony. The toll of the chicks is comparatively 

 less, the shorter the time from the hatching of the 



Survivor) 



Time 



Fig. i8. The "spread" of time in which eggs are laid 

 in a colony of herring gulls affects the percentage that 

 survive. The smaller the colony the longer the spread, 

 and the fewer survivors. [From Darling (39) by permis- 

 sion of The Macmillan Co.] 



first fuzzy young gull until the last one changes to 

 a young fledgling with adult feathers. These relations 

 are graphically shown in Figure 18. 



Darling thinks that the greater success of the larger 

 colonies does not lie in any vague factor of mutual 

 protection, but in the nearer approach to simultane- 

 ous breeding throughout the colony. This is a phase 

 of social facilitation which will be discussed more 

 fully in a later chapter. 



These observations need to be extended and con- 



