BIRDS 



471 



derived from the lining of the crop, which undergoes rapid 

 growth during the nesting season. 



When the young bird is fed from the crop it sometimes 

 makes the operation more easy by thrusting its head into the 

 mouth of its parent, as in the case of the Black Cormorant 

 {^Phalacrocorax carbo, fig. 992). 



The sanitation of the nest is sometimes entirely neglected, 

 as in Gannets and Kingfishers, necessarily so in the case of 

 Hornbills (see p. 466). But in probably the majority of birds 

 it is attended to by the parents with scrupulous care, as will 

 have been gathered 

 from the accounts al- 

 ready given of the 

 Skylark and Chaffinch. 

 Sometimes, as in the 

 House-Martin, the old 

 birds teach the young- 

 ones how to avoid foul- 

 ing the nest. 



Young birds which 

 may almost be said 

 to run from the egg 

 are usually protectively 

 coloured, and crouch 

 when alarmed, as al- 

 ready described for the 

 Emeu (see p. 450) and, in an earlier section, for some of the 

 Plovers (see vol. ii, p. 285). Apparently the first case of the kind 

 to attract observation was that of the Stone-Curlew {OEdicnetmis 

 scolopax), described, so long ago as 1768, by Gilbert White (in 

 The Nahiral History of Selborne): — "The history of the stone- 

 curlew ... is as follows. It lays its eggs, usually two, never more 

 than three, on the bare ground, without any nest, in the field; so 

 that the countryman, in stirring his fallows, often destroys them. 

 The young run immediately from the egg like partridges, &c., 

 and are withdrawn to some flinty field by the dam, where they 

 skulk among the stones, which are their best security; for their 

 feathers are so exactly of the colour of our grey-spotted flints, 

 that the most exact observer, unless he catches the eye of the 

 young bird, may be deluded." Another familiar example is that 



Fig. 992. — Black Cormorant {Phalacrocora.x carbo) feeding its Young 



