182 Mr. G. D. Rowley on certain Tacts in 



to the Cuckoos* eggs. One would hardly think it necessary for 

 Nature to do this, since we well know that most birds will lay to 

 an egg of another species introduced into their nests, and fre- 

 quently to a round stone, not to say a boy^s marble ; indeed I have 

 observed a Muscicapa grisola, having lost her eggs, sitting hard 

 for two days on an empty nest. The impulse to sit is so strong 

 as to be very difficult to resist. I have frequently, and (so far as 

 sitting goes) with success, changed the eggs of birds. Not long 

 since I substituted three eggs of Fringilla calebs for the same 

 number of a Coccothraustes vulgaris, to which the latter laid two 

 more very contentedly. But I need not cite more examples, for 

 similar instances have probably occurred to most oologists. 



If, then, Cuculus canorus has this strange and (as I think) 

 unnecessary property, does the same gift extend, under a simi- 

 lar necessity, to the equally parasitical C gJandarius ? Unfortu- 

 nately I have only one specimen of the egg of this species, sent 

 with three companions, the property of Corvus comix. One speci- 

 men certainly does not tell us much ; but I see nothing to favour 

 the supposition alleged. Again, does the Australian Scythrops 

 novcB-hollandiiS deposit an egg in colour resembling that of 

 Gymnorhina tibicen^, which, according to Mr. Gould, is some- 

 times its foster-parent ? The more honest habits of the Cuckoos 

 of the New World prevent our getting any help from them. 



The ingenious idea struck out by Dr. Baldamus, and recorded 

 of old time of animals about to produce young, that strong and 

 long-wearing impressions upon the senses affect the female bird 

 with regard to the colour of her eggs, can hardly, I tbink, be 

 entertained. It is true that the colouring is the last stage in 

 the egg-making process ; but how does a Cuckoo know what hue 

 will be suitable, when she deposits her egg in an empty nest ? 

 That this is sometimes the case, I fully believe. I refer again 

 to my nest (already mentioned) of the 5th of May 1862. But 

 it may be said that, in that instance, the Cuckoo turned out all 

 the eggs of the Accentor and only left her own. Now I have 

 very frequently known the Cuckoo turn out some eggs, but 

 never, according to my experience, have the whole been ejected. 



* Dr. George Bennett states (P. Z, S. 1861, p. 183) that the eggs of this 

 species vary among themselves most remarkably. — Ed. 



