YOUNG BIRDS IN THE NURSERY 87 



existence, stands the fact that incubation and brooding 

 are impossible after the fashion prevaiUng among birds 

 elsewhere. Each bird lays but a single egg. To incubate 

 this on the ice would obviously be impossible : as a con- 

 sequence, as soon as laid it is transferred to the back of 

 the mother's feet and covered by the overlapping feathers 

 of the abdomen, the formation of the usual " brood-spot " 

 forming a convenient cavity for its reception. But even 

 this singular device affords only a qualified success, for, 

 as Dr. Wilson has shown, a large percentage of brooding 

 birds are without eggs or young, and this loss seems to 

 increase their desire to satisfy the cravings of the parental 

 instinct. As a consequence, every one of these childless 

 birds strives to adopt that of its more fortunate neigh- 

 bours ; leading to a competition which, of its kind and 

 in its keenness, is without parallel. 



" Incubation," Dr. Wilson tells us, " is carried out not 

 by one bird only, or by a single pair, but by a dozen or 

 more, which stand patiently round for a chance to seize 

 either a chicken or an egg as the post of incubation 

 becomes vacant." Not only do the childless females take 

 their turn with the hens that are more fortunate, but the 

 males also help, and so every individual has the same bare 

 patch of skin at the lower part of the abdomen against 

 which the egg is pressed for warmth. 



" What we actually saw," writes Dr. Wilson, " again 

 and again, was the wild dash made by a dozen adults, 

 each weighing anything up to ninety pounds, to take 

 possession of any chicken that happened to find itself 

 deserted on the ice. It can be compared to nothing better 

 than a football ' scrimmage,' in which the first bird to 

 seize the chicken is hustled and worried on all sides by 

 the others while it rapidly tries to push the infant between 



