MR. .1. H. GURNEY ON THE ECONOMY OF THE CUCKOO. 367 
received in ‘ The Times,’ of its being heard elsewhere, for a Cuckoo 
is not very likely to be in song in December. 
The chief points in Cuckoo lore to which I should like to invite 
the further attention of Norfolk naturalists, because there is still 
some more to be learnt about them, are : — 
The colour of Cuckoo’s eggs. 
The removing of eggs. 
The eating of birds’ eggs. 
The removing of nestlings. 
The watching of their own eggs. 
The habits of the young Cuckoo. 
'file anatomy of the Cuckoo. 
The dimorphism of its hepatic plumage. 
Cuckoo’s Eggs. 
Cuckoo’s eggs, and all that appertains to them, is an inexhaustible 
subject when naturalists meet in conclave, and it is one which has 
a fascination for every oologist. Even now we do not seem to 
have fathomed it in spite of the German assistance quoted at 
the head of this article, but the subject is concisely treated in 
1 baiting's ‘ Our Summer Migrants.’ Our Cuckoo lays blue 
eggs oftener than is thought, and Corey sirs jaeobinus , a Cuckoo 
inhabiting Africa and India, always lays them : to say blue Cuckoo’s 
eggs have never been met with in England is quite incorrect, for 
they have been found on four or five occasions. In one nest we 
learn the blue egg was very little larger than a Hedge Sparrow’s, 
but it produced a Cuckoo, which only shows how easily they may 
be passed over. Dr. Key, considered a great authority, says Cuckoo’s 
eggs vary more in colour than those of any other bird, and that is 
a fact, and they are comparatively hard and thick, which abnormally 
large eggs are not. Dr. Key says that each Cuckoo lays twenty 
eggs a year, and several writers are of opinion that each individual 
Cuckoo keeps to its own district. If this be so, probably only 
about a third of the twenty eggs result in young Cuckoos, consider- 
ing how scarce, comparatively speaking, they are ; and the rest of 
the eggs must be lost from one cause or another, of which more 
later on. Cuckoo’s eggs often, but by no means always in this 
country, whatever may be the case on the Continent, bear a curiously 
protective resemblance to the eggs of the foster-bird. To the late 
August Baldamus belongs the credit of this discovery, though 
