154 THE BIRDS OF SHERWOOD FOREST. 
sequently (as a general rule) lays only in the nests of 
one species.” Such is, I believe, a fair outline of the 
theory, and the italics are the Doctor's, not mine. 
The publication of the article in the Zoologist 
elicited a discussion in the Field, in which Mr. 
Hewitson, Mr. Newman, Dr. Bree, Mr. Dawson Rowley, 
and others took part, the weight of opinion being adverse 
to the theory. It is but just that the views of a man 
of eminence like Dr. Baldamus, made in good faith, 
however startling and contrary to our preconceived 
conclusions, should be received with respect, and be 
subjected to a careful examination. I must, however, 
frankly state that I cannot accept his conclusions, be- 
cause I doubt the facts from which they are drawn. 
I never found the eggs of the cuckoo to vary in any 
great degree ; they most resemble in colour and mark- 
ings the light varieties of the skylark’s, and next, those 
of the pied wagtail, and these I believe to be the usual 
types. So eminent and experienced an oologist as Mr. 
Hewitson holds this opinion, and Mr. Rowley, who pos- 
sesses the nests and eggs of fourteen species, with a 
cuckoo’s egg in each, twelve of which he took with his 
own hands, says that out of all these, only two (and 
those the two he did not take himself) display any re- 
semblance between the intruder and its companions, and 
in both to him it is very faint. 1 believe that what Dr. 
Baldamus supposed were cuckoo’s eggs, were only ab- 
normally large ones of the birds in whose nests they 
were found, and this variation in size is well known to 
every oologist and every bird’s-nesting schoolboy. It 
would be strange indeed if the cuckoos laid these varied 
eggs in Germany and not in England, and yet British 
ornithologists have never discovered them. Another 
