PARENTAL CARE AND NEST-MAKING 315 



combination against attack. Coues reports having seen 

 little cliff-swallows nesting in the immediate neighbourhood 

 of the prairie-falcon. Kropotkin refers to this case in his 

 " Mutual Aid " (1904, p. 35) : " The little peaceful birds had 

 no fear of their rapacious neighbour ; they never let it 

 approach their colony. They immediately surrounded it 

 and chased it, so that it had to make off at once." So wild 

 duck will unite their forces in driving off an eagle, and 

 wagtails a hawk. The bold lapwing will fly close to an 

 intruding enemy and summon its neighbours to its assistance . 

 Brehm writes of the common lapwings : "To see them 

 attacking a buzzard, a kite, a crow, or an eagle, is one of the 

 most amusing spectacles. One feels that they are sure of 

 victory, and one sees the anger of the bird of prey. In such 

 circumstances they perfectly support one another, and their 

 courage grows with their numbers " (quoted by Kropotkin, 

 '* Mutual Aid," 1904, p. 25). The same sort of concerted 

 action is familiar in many other birds, such as gulls and terns. 



The social note becomes more definite among birds which 

 move about together in flocks, like the herds of mammals, 

 for there may be leaders and sentinels and other suggestions 

 of division of labour. This may be illustrated by cranes and 

 flamingoes, by parrots and the crested " American partridge " 

 {Lophornyx calif ornicus). In some cases several sentinels 

 are posted when the flock is feeding, and it is almost 

 impossible to take them by surprise. 



Another less frequent feature is exhibited by pelicans, 

 namely co-operation in the quest for food. Of the pelicans 

 it is said that " they always go fishing in numerous bands, 

 and after having chosen an appropriate bay, they form a 

 wide half-circle in face of the shore, and narrow it by wading 

 shorewards, catching all the fish that happen to be enclosed 

 in the circle. On narrow rivers and canals they even divide 

 into two parties, each of which draws up on a half-circle, 

 and both wade to meet each other " (quoted by Kropotkin, 

 *• Mutual Aid," 1904, p. 23). 



Co-operative sociality is also suggested by the Republican 

 Birds, where there is combination in building a big common 



