president’s address. 
29 
PRESIDENT’S ADDRESS* 
DY R. W. CHASE. 
( Continued from page 6.) 
Returning to tlie cuckoo. I believe that, being a voracious 
feeder, it requires a considerable tract of country to sustain 
one, and that upon arriving, each bird takes up its abode in a 
certain neighbourhood, and uses such nests as are plentiful 
in that locality. It is the scarcity of suitable nests that 
causes us to hear of a cuckoo’s egg being found in the nest of 
such species as the magpie, &c. 
Concerning the coloration of birds’ eggs in general, these 
beautiful tints and varied markings must at once strike even 
a casual observer. 
I think there is little doubt that the chief use of colouring 
in eggs is protective, or, I may say, entirely so. The means 
by which the various colours are produced is more difficult to 
assign. 
Some writers consider that the colour in eggs is influenced 
by the plumage of the bird, and that the colour, etc., of one is 
dependent upon and analogous to the other; to a certain 
extent this may be so, as food and organic substances intro¬ 
duced into a bird’s system affect the colour of the plumage. 
I see no reason why the colouring matter of the egg shell 
should not likewise be acted upon. It is a fact that the same 
species inhabiting distinct and different localities will differ 
in the colour of their plumage and eggs ; for instance, denizens 
of Fenland will have full and darker plumage and lay more 
richly coloured eggs, whereas those occupying hi gif, dry, 
sandy districts will be pale in comparison. That birds are 
able to control or alter the normal markings upon their eggs, 
at will, I consider absurd, although we find an endless 
variation, both in ground colour and markings, in most eggs, 
but especially so in some species, the tree pipit, for instance. 
At the same time, I am convinced that the bird is quite an 
involuntary agent in the matter. Nor can I agree to the 
supposition that birds who now lay spotted or marked eggs 
in covered or domed nests will ultimately lay white or 
unmarked eggs, because there is no further necessity or use 
for the markings, as the nest affords protection from discovery. 
* Transactions of the Birmingham Natural History and Micro¬ 
scopical Society. 
