EARLY LIFE OF THE YOUNG CUCKOO 85 
Although we have accomplished this much, we have not yet 
proved in any way why the egg is so very small in comparison 
with the size of the bird, but my friend, Mr. John Craig, to 
whom I shall shortly refer, has, so far as I am aware, produced 
the best explanation of this by stating that he considers it is for 
the purpose of quick incubation and to allow the egg to be 
deposited in birds’ nests which are smaller than the cuckoo, 
and also to allow the cuckoo to carry the egg in her bill to its 
destination without breaking it. 
As to why the bird does not build a nest for itself, my friend 
also put forward the theory that if it did, and laid four or five 
eggs to the clutch, one on each successive day, the instinctive 
desire implanted in the young cuckoo of clearing everything out 
of the nest in which it is hatched, is so strong that there would 
be a struggle among them for possession of the nest, and the 
weakest would perish, and they would be in a worse position 
than at present for perpetuating their species. Mr. Craig thinks 
that it is incompatible with the perpetuating of their species for 
more than one egg to be deposited in the same nest. I must say 
that so far these observations are the most practical that I have 
as yet seen, and too much prominence cannot be given to the 
fact that Mr. Craig has paid particular attention to the curious 
life-history of this interesting harbinger of summer, and the 
opinions at which he has arrived are the result of several years’ 
hard work in field ornithology. 
I have entitled this article “ The Early Life of the Young 
Cuckoo,” and do not therefore propose to enlarge on the life and 
habits of the adult bird, but to proceed to describe a most inter- 
esting series of experiences and experiments with some young 
cuckoos which Mr. Craig successfully carried out during the 
summer of 1899. 
Up to the date of Mr. Craig’s valuable observations con- 
siderable doubt existed as to how the young cuckoo ejected its 
foster-brothers and sisters or the eggs out of the nest in which it 
happened to be placed. Many theories were expounded, but it 
seemed that although so many were ready to put their theories- 
and experiences into print, very few indeed had actually 
witnessed the occurrence. We had had drawings illustrating 
the young cuckoo in the act of ejection, but these were not 
convincing enough to those of a sceptical frame of mind, although 
those who had actually witnessed the performance readily 
accepted the drawings as correctly representing the mode of 
procedure. 
Controversy in a certain channel reached fever height in 1899, 
and my Ayrshire friend at once set to work and secured a 
wonderful series of photographs revealing, as well as illustrating, 
the young cuckoo in the very act of ejecting an egg and a young 
bird, which photographs and experience have by this time been 
heard of throughout the ornithological world. 
What Mr. Craig has accomplished is a perfect revelation to 
