X 
INTRODUCTION. 
ceal them in holes, are white, because in such situations colour 
would be displayed to no purpose. 
The n um ber of eggs laid by various tribes of birds, as well 
as by the different genera of the same family, vary much. 
The more typical species of these are, however, for the most 
part nearly alike in this respect. In every instance we shall 
find the same beneficent influence acting for our welfare; in¬ 
creasing rapidly those species which are of the greatest use to 
us, and bestowing upon those intended for our more immediate 
benefit, a most wonderful power of ovo-production; and at the 
same time curtailing in their numbers those species which, in 
their greater increase, would soon become injurious to us. Most 
of the Rasores, which, as game, form so agreeable an addition 
to our table, as well as the Duck tribe, lay numerous eggs. 
Some of the Warblers, and the various species of Titmice, 
which render us such essential service in the destruction of 
the numerous insects which would otherwise become a nui¬ 
sance, are unusually prolific. 
In their relative sizes, the eggs of birds differ in a remark¬ 
able degree from each other, as I have shown, when describing 
those of the Guillemot; and this will be seen by comparing 
those of a few species. The Guillemot and the Raven are 
themselves of about equal size; their eggs vary as ten to one. 
The Snipe and the Blackbird differ but slightly in weight; 
their eggs remarkably. The egg of the Curlew is six or eight 
times as large as that of the Rook ; the birds are of about 
the same size. The eggs of the Guillemot are as big as those 
of an Eagle; whilst those of the Snipe equal in size the eggs 
of the Partridge and the Pigeon. The four eggs of the Jack 
Snipe weigh nearly as much as the bird itself. The reason 
of this great disparity in size is, however, obvious ; the eggs 
of all those birds which quit the nest soon after they are 
hatched, and which are consequently more fully developed at 
their birth, are very large, and yet so admirably formed to 
occupy the least possible space, that the Snipe has no more 
difficulty in covering its eggs, though apparently so dispropor¬ 
tionate, than the Thrush or the Blackbird. 
