Imitators of Nightingale. 269 



He has found four spotless eggs and one normal one 

 in the same nest. The occurrence of the eight eggs 

 together, apparently laid by two hen birds, is inter- 

 esting, as it is known that occasionally the birds 

 build two nests in conjunction." Everyone knows 

 that pheasants will often lay eggs in partridges' nests 

 and in effect sometimes share the brooding with 

 them. 



It is a notorious fact that building in the same tree 

 or near to each other disarms egg - suckers ; thus 

 pigeons have been found building on the same trees 

 as magpies and jays, and in most of these cases it 

 was found that the pigeons' eggs escaped the natural 

 marauder so near to them. So, with birds, not dis- 

 tantly related, building close to each other might well 

 lead in time to the sharing of one nest. 



All, however, bears more or less directly on the 

 central question of birds' song, whether instinctive, 

 hereditary or imitative and learned by listening to 

 other birds' notes : a whole lot of birds imitate the 

 songs of other birds, and by it very materially modify 

 their own — thus thrushes and yet more blackbirds and 

 starlings imitate the song of the nightingale, and 

 sometimes so perfectly up to a certain point that their 

 song might well be mistaken for the nightingale's. 

 Light is much needed on this point, and it can only 

 be secured by ornithologists in one part taking up 

 special lines of enquiry and observation, and corres- 

 ponding with those in other parts ; so that, from a 

 wide range of observations, general laws may be 

 reached. 



One experiment I propose to myself on the first 



* Dr. Bowdler Sharpe's British Birds, p. 266. 



