president’s address. 
38 
often have to go far, and leave the nest for a considerable 
period, so as a means of protection a covering of twigs is 
placed over the nest, leaving a hole at the side for entrance. 
How came the magpie to adopt this method ? From experience ? 
I think the only schoolmaster employed was “ Instinct, or an 
involuntary stimulus of an innate unknown power,” causing 
such action without any intervention of reason as the result of 
such actions. 
I therefore think we may conclude that (1) colour, both in 
birds and their eggs, is intended as a means of preservation 
of their kind from natural enemies by the adaptation of their 
hues to the colour of their surrounding in their usual habitat; 
a most forcible instance of design, clearly pointing to the 
existence of an “ omniscient great First Cause.” 
Mudie has beautifully illustrated it by comparing “ the 
ptarmigan to lichen rock in summer, hoar frost in autumn, 
snow in winter ; grouse are brown heather ; black grouse are 
peat, bank, and shingle ; partridge, clods and withered stalks 
all the year round.” 
(’2) That any variation from the normal coloration is not 
dun to any action of the birds themselves, but is caused by the 
amount of nutriment obtained, or some speciality in the soil 
or climate they may inhabit, such variation being often only 
slight and hardly ever permanent. 
Alteration in colour is easily obtainable ; the high colour 
in canaries produced by cayenne feeding, the dark bullfinches 
by hempseed, from which unnatural causes (such extreme cases 
not being found in nature) erroneous conclusions are drawn. 
The most remarkable variations are those obtained in 
animals or birds in a state of confinement or domestication, 
consequently not proper or safe examples upon which to found 
theories. 
(8) That in cases where the eggs are not protected by their 
colour, the plumage of the parent assimilates with the sur¬ 
roundings instead, and that in many cases, upon the old bird 
leaving the nest, the eggs are covered up. 
The case of the wood pigeon and turtle dove is most 
puzzling, and I must confess that T am unable to solve the 
mystery, which I put down to my want of knowledge, but at 
the same time cannot accept the theory that having descended 
from hole-breeding ancestors, they have adopted the system 
of nesting in trees and hedges as an improvement; by the 
same argument, they ought to have adopted coloration as a 
means of protection by concealment, which they have not. 
That nests are not constructed by “ imitation or memory,” 
but from instinct inherent, or as it has been expressed, “ an 
