FAMILY CARES— BUILDING THE HOME. 123 



build no nest but deposit their eggs on the bare 

 ledges of rocks which go to make the cliff's around 

 our coasts. In these birds the form of the egg is 

 specially modified on account of this habit. Their 

 shape is roughly pear-shaped, so that, when blown 

 by the wind, the egg revolves round on its small 

 end, instead of rolling off into the sea below. As it 

 is, many thousands do meet this fate every year. 

 It used to be a favourite sport of wretches armed 

 with guns to fire a shot from the top of the cliffs 

 on which these birds nested, so as to startle the 

 sitting-birds, and cause them, as they hurriedly 

 left their eggs, to knock them off their ledges in 

 thousands into the sea, in order that they might 

 afford sport, or gratify the hideously morbid 

 curiosity of tourists. 



In all the cases which we have considered, in 

 which birds make little or no provision for their 

 eggs in the shape of a nest, but leave them fully 

 exposed to view, it will be noted that these, for. 

 the most part, so closely resemble surrounding 

 objects as to make further attempt at conceal- 

 ment unnecessary. It is almost certain that origin- 

 ally all birds laid white eggs, as do their cousins 

 germane the reptiles. But as there is at least 

 one reptile in which there is a distinct tendency 

 to produce a coloured, rust-spotted shell, viz., the 

 Taut era-lizard of New Zealand, so there may have 

 been many birds in which the same tendency 

 developed itself. Of these many would produce 

 eggs much more strongly marked or spotted than 

 their neighbour's. If a number of such birds 

 migrated, say, from the forest-land of their an- 

 cestors to the plains or meadows, a process of 



