BIRDS OF PREY. , 27 
in the destruction of various kinds of vermin more or less 
injurious to game; but it has been a fruitless task, and 
one instance which he may be able to adduce of either 
one or the other having dined or supped on game (for I 
do not deny that they sometimes vary their diet in this 
way), fairly outweighs with him all their good qualities, 
and makes them outlaws at once. 
Their labours are, indeed, highly beneficial to the 
farmer and the forester, their chief food being field mice, 
of which they destroy vast numbers, and various kinds 
of beetles, especially the cockchafer; birds are some- 
times preyed upon, though I believe not so frequently 
as by others of the family—at least, I have observed 
that the kestrel is less subjected to the noisy pursuit of 
small birds, and I have often watched it hunting where 
no notice of its presence has been taken. 
It is plentiful with us throughout the year, al- 
though I have no doubt that it is partially migra- 
tory, as we certainly receive an accession of numbers 
in the spring, which again gradually leave us in the 
autumn. 
I have known the nest placed in the hollows of some 
of the blasted tops of the old oaks, and sometimes a 
deserted nest of the crow or jay bas been made use of. 
I have an egg in my collection which, instead of being 
blotched and marbled in the usual manner, is of a uni- 
form chestnut colour. 
What I have said of the kestrel cannot, however, be 
applied to the Sparrowhawk (Accipiter fringillarius). 
Its appearance is the signal for a general commotion, 
and the cries of alarm which are uttered when first the 
presence of the enemy is detected are well understood 
by various species, and swallows, linnets, chaffinches, 
