66 Life History of Common Cuckoo. 



egf^s in hedge-sparrow's nests, and also two brown 

 blotched cuckoo's eggs in hedge-sparrow's nests. I 

 do wish observers would make careful note of this, 

 that some idea of the proportion obtaining in these 

 matters might be reached, and further inferences as 

 to the cuckoo's power and knowledge carefully drawn 

 from the facts observed. 



In the collection of clutches of eggs in the British 

 Museum, are cuckoo's eggs showing the exact colour 

 and markings of the eggs of the birds victimised : 

 *' pied wagtails, yellow wagtails, blue-headed wagtails, 

 meadow-pipits, tree-pipits, skylarks, chaffinches, reed- 

 warblers, and sedge- warblers, orphean- warblers, etc." 

 So says Dr. Bowdler Sharpe, in effect, and he thus 

 further notices curious points : 



*' The small size of the egg laid by the cuckoo, con- 

 sidering the bulk of the bird, is another peculiar 

 feature in its economy. Great diversity of colour, 

 also is one of its characteristics, and considering the 

 various types of eggs laid by the cuckoo, it is not 

 wonderful that the theory exists that the bird places 

 its eggs in the nest of a species, the eggs of which 

 most resemble its own in colour. That there is great 

 truth in this theory I firmly believe, otherwise, it 

 would be difficult to account for the fact that blue 

 cuckoos' eggs should be placed in the nest of a red- 

 start, which likewise lays blue eggs. In the British 

 Museum are such clutches of eggs, and also blue eggs 

 placed in the nest of a pied fly-catcher, the eggs of 

 which are also blue. The fact of the cuckoo produc- 

 ing a blue egg was for some time doubted in England, 

 though well known in Germany ; but the question 

 was set at rest by two English ornithologists, Mr. 



