60 Wizard Cuckoos 



hen cuckoo deliberately places her egg in a nestful 

 chosen from their close resemblance to her own. 

 Cuckoos' eggs vary much in colour, and the colour 

 generally shows a partial approximation to that of 

 the eggs among which they are found. But this 

 resemblance is seldom so thorough that a closer one, 

 or many equally close, cannot be picked out among 

 a score or two of instances. If we examine a large 

 series of cuckoos' eggs together with those from 

 the same nests, and not specially picked for the 

 purpose of bringing out a resemblance, the likeness 

 of the cuckoo's egg to those among which it was 

 found is often no greater than to some nestful 

 of a different species. There are very few cases 

 in which the likeness is close enough to rank with 

 such striking, familiar instances of protective re- 

 semblance as that of the stone curlew's or tern's 

 eggs with their pebbly surroundings. 



None the less, it is a striking fact that the cuckoos' 

 eggs found in the nests of the several species of 

 foster-parents show a distinct similarity among 

 themselves. Cuckoos' eggs from reed-warblers' 

 nests, for example, are suffused with a peculiar 

 bronzy -green, though this is by no means suffi- 

 ciently like the distinct mottlings of the reed- 

 warbler's eggs to deceive for a moment a human 

 eye. From this prevailing likeness between cuckoos' 

 eggs from similar nests, together with their vaguer 

 general likeness to the eggs among which they are 

 found, it is difficult to avoid the conclusion that the 

 cuckoos' dependence upon various species of birds 

 does influence the colour of its eggs in some degree. 



