Wonderful Mimicry. 65 



Sharpe assured me, however, that they had in reserve 

 many blue eggs of the cuckoo; which just leads to 

 the question, in what proportion of cases the brown- 

 spotted eggs are intruded into the hedge-sparrow's 

 nests, as in the three cases noted above. 



Here arises a difficulty about the theory of the 

 cuckoo always laying eggs the same colour. For, 

 if the blue-laying cuckoos know the hedge-sparrow's 

 nest, and use it, these facts would indicate failure on 

 the part of the cuckoos who lay brown-blotched eggs, 

 and place them too in the nests of accentors, or lay 

 blue or bluish eggs in the nests of birds which have 

 brown, or brown spotted, or blotched eggs. I myself, 

 in Essex, last year (1898) found two blue cuckoo's 



the cuckoo's egg is the counter-part of the hedge-sparrow in texture 

 and colour, though almost twice as large — a wonderful instance 

 of mimicry. In all the other cases (Nos. 2 — 6), the cuckoo egg 

 is the ordinary dull speckled-brown — a striking contrast. In 

 the case of two other species — the pied fly-catcher (Silesia), and 

 the redstart (Vaalkerstaad) , both of which lay blue eggs — the 

 cuckoo imitates their colour, but the egg is much larger. 

 In the following instances the imitative colouring is very perfect 

 Lesser whitethroat, mottled greenish-grey (Halle, Saxony) 

 Orphean warbler, white pale greenish-blue, spotted (Malaga) 

 garden warbler, buff-speckled (Brandenburg) ; blue-headed 

 yellow wagtail, grey speckled (Frankfort-on-Oder) ; barred 

 warbler, pale mottled green (Alsace) ; meadow pippit, reddish 

 brown (North West Cheshire) ; white wagtail, grey speckled 

 (Germany) ; linnet, white greenish spots (Germany). In the 

 case of the red-backed shrike or butcher-bird (Marne), the resem- 

 blance between the two eggs in size and colouring— cream body 

 colour with reddish cloud at the upper end — is so remarkable 

 that one might be pardoned for imagining that there had been 

 some mistake.'' And yet in spite of the words in this extract, put 

 in italics by me, Dr. Bowdler Sharpe unaccountably says there 

 is no record of a blue cuckoo's egg in a hedge-sparrow's nest ! 



