CHAPTER 7 



SOCIAL AND SEXUAL BEHAVIOUR 



BEFORE WE describe their exciting and varied life-histories we ought 

 to review the present state of our knowledge of the social and 

 sexual behaviour of sea-birds, from which a general pattern emerges 

 which enables us to understand the meaning of their fascinating, 

 and often very peculiar, specific ceremonies and displays. 



After normal 'maintenance activities' (as they have to be called) 

 the life of the sea-bird is centred round its reproduction, without 

 which the species cannot continue. From these two activities all 

 sociality (gregariousness, flocking or living together) arises; and sexual 

 behaviour is the most important aspect of social behaviour. 



Pair-formation requires the location of a partner, the attainment 

 of which in the first place involves the breaking down of certain 

 safeguards and habits with which the individual protects itself during 

 the non-breeding period, and the establishment of a state of intimacy 

 between male and female. The mechanism or behaviour by which 

 the individual ring-fence is maintained on the one hand, and by which 

 it is altered in order to secure the sexual bond on the other hand, is 

 a remarkable phenomenon, popularly known as display. 



In sea-birds, which are monogamous, display is mutual. The 

 unilateral display and courtship behaviour of polygamous land-birds 

 (such as the ruff, blackcock and jungle-fowl) hardly concerns this 

 chapter as comparative material. Polygamy is usually associated 

 with a brief but brilliant display or tournament between conspicuously 

 adorned males, which, after mating, leave all the work of incubation 

 and brooding to the dull-coloured females. The polygamist is an egoist 

 occupied solely with the three m's: mating, moulting and maintenance. 

 The male sea-bird, a monogamist, is by human standards a model 

 husband, taking equal responsibility with his mate for nest-making, 

 incubation, and rearing duties. Darwin (1871) overlooked the signi- 

 ficance of mutual display when promulgating his theory of sexual 



