3724 The Zoologist — October, 1873. 



widely ; and when we come to discuss the probable reasons for 

 such variation in colour, and assimilation of colour to the eggs 

 of the selected foster-parents, there are almost as many theories as 

 disputants. The German writers, indeed, appear to be unanimous 

 in ascribing this peculiarity to the provision of Nature that " the 

 cuckoo's egg, coloured and marked in a very considerable degree 

 like the eggs of those birds in whose nests they are about to be laid, 

 might the less easily be recognised by the foster-parents as substi- 

 tuted ones." ('Zoologist' for 1868, p. 1157.) But this explanation 

 does not seem to be accepted in England, where it has been 

 more than once pointed out that such a provision is wholly 

 unnecessary, inasmuch as the foster-parent willingly accepts the 

 intruded egg, whether with or without such resemblance to its own 

 in colour. The cause above assigned therefore does not seem to 

 our ornithologists to be adequate, and so a variety of conjectures 

 has been hazarded, and a multitude of reasons suggested, but none 

 of them to my judgment in any degree convincing, or indeed so 

 plausible, as the original motive assigned by Dr. Baldamus and his 

 followers. 



And yet, could we but discover it, there must be some sufficient 

 cause for so peculiar a habit. I hardly like to hazard a conjecture, 

 which may in all probability turn out to be a mere fancy ; but it 

 has occurred to my mind many times of late whether it is possible 

 that the young cuckoo can by any means derive from its foster- 

 parent so much of that nurse's nature (whether by the diet on which 

 it has been brought up, on which exclusively the young of the 

 foster-parent would, had ihey survived, have been fed or oliierwise), 

 as when its own turn for breeding arrived, to affect (though un- 

 consciously to itself) the colouring of the eggs it laid. 1 do not 

 offer this as a solution of our difficulty : I merely throw it out as a 

 hint or a fancy which h^s suggested itself to my thoughts; but 

 before it is rejected as far-fetched and ridiculous, let me submit 

 these few considerations to those who care to pursue the enquiry. 



First, however, I would mention in passing, as worthy of obser- 

 vation, that the young cuckoo has been oftentimes declared to have 

 acquired the exact vote of its foster-parents. Of this Mr. Thompson 

 gives decisive evidence in the case of a young cuckoo which was 

 taken out of a titlark's nest, and of which he says, "for several 

 weeks after the cuckoo was placed in confinement it uttered, when 

 in want of food, a note so closely resembling that of the titlark 



