10 BRITAIN'S BIRDS AND THEIR NESTS. 



an obvious purpose — the eggs ' pack ' into smaller space. 

 Where one or two, or half-a-dozen or more, are laid, the 

 eggs tend to be oval — for example, in game-birds — and it is 

 sometimes impossible to say which end is which. To this 

 the Guillemofs egg is an exception ; but its shape is of 

 use in another way. If the wind, or the departure of the 

 incubating bird, sets the egg in motion on its narrow 

 ledge, it is often saved by its tendency to rotate without 

 rolling. It moves, and yet remains in one place. This can 

 be demonstrated experimentally ; but a blown egg will not 

 answer. It is true that the eggs often fall ; when startled 

 by a gunshot the birds often leave with such haste that 

 they precipitate a shower of eggs into the sea. 



The nesting habits of the various kinds of Auks are on 

 the whole much alike. Little difference exists between 

 those of the Guillemot and those of the Razorbill. In 

 speaking of Auks generally, a German naturalist-traveller, 

 of half a century ago, gives an amusing account of these 

 habits. 'During the brooding season their social virtues 

 reach an extraordinary height,"* he says. The males out- 

 number the females, according to his observations ; but 

 whilst among other birds such a disproportion gives rise 

 to ceaseless strife, yet among these Auks peace is not dis- 

 turbed. Not only do the ' bachelors "" share in the duties 

 of incubation, sitting when both parents are at sea, but 

 their presence ensures that there will be no orphans on the 

 cliffs. ' Should the male of a pair come to grief, his widow 

 immediately consoles herself with another mate, and in the 

 rarer cases of both parents losing their lives at once, the 

 good-natured supernumeraries are quite ready to finish 

 hatching the egg and to rear the young one.' Needless 

 to say, these statements must be received with considerable 

 reserve. 



The young bird emerges from the egg covered with 



