THE FEATHERS. 
69 
exclusive of these, which may he called natural variations, 
there are occasional departures from the usual rule, of an 
unnatural character. Thus Blackbirds are not unfrequently 
found very considerably mottled with white. Woodcocks are 
now and then shot, of a delicate and uniform fawn colour. 
We have also seen white Swallows, and a few other small 
birds; and amongst Crows and Rooks, one or two inter- 
lopers may he occasionally observed, with more or less white 
feathers peeping out from their glossy wings. Closer obser- 
vations may probably throw additional light upon' this sin- 
gular peculiarity, and we suspect that it will he generally 
found that it extends through several generations of birds 
reared by the same pair. In one instance we know, indeed, 
that this was the case. A pair of Rooks were in the habit 
of building in a wild spot near Ruthin, where there were 
few trees affording shelter for others. The attention of the 
tenant on the farm was soon attracted by the singular 
appearance of two white young ones, and, to his surprise, for 
three or four years, the same phenomenon occurred, two white 
Rooks being the invariable and sole nursery establishment 
of this solitary sable pair of old birds. This year (1837) the 
young ones were taken and reared. A change of plumage 
has also been observed to take place occasionally by limiting 
the bird to a particular sort of food ; thus bird-catchers say, 
that by the use of hemp- seed, Bullfinches and some other 
kinds of birds will frequently assume a darker colour. Fright, 
again, (as in the case of human beings, whose hair has been 
known to change under great excitement or alarm,) it is said, 
will produce similar effects on birds ; in proof of which, we 
have been assured on the authority of a friend, that a Bull- 
finch in his possession turned black in a few hours after 
having been terrified by the approach and attack of a cat upon 
its cage. 
