BRITISH BIRDS. 
308 
feathers of the back are black, edged with white, 
and thofe of the wing coverts and fcapulars, blue 
grey, bordered with black near their margins, and 
edged with white : the quills black, edged a little 
way from the tips with blue grey : the under parts 
and tail coverts white : the thighs are marked with 
dulky lines or fpots, and are black near the knees : 
the tail is black, and five inches and a half long : 
the legs and feet dufky, very thick and fhort, and 
have a ftumpy appearance. 
In fevere winters, thefe birds are not uncommon 
in this kingdom, particularly on the northern and 
wefiern parts, where, however, they remain only a 
fhort time, but depart early in the fpring to their 
northern wilds, to breed and fpend the fummer. 
The hiftory of the Bernacle has been rendered 
remarkable by the marvellous accounts which were 
in former times related concerning their propaga- 
tion, or rather their growth. Almoft all the old 
naturalifts, as well ornithologifis as others, affert 
that they were produced from fhells which grew out 
of rotten fhip-wrecked timber, and other kinds of 
wood and trees which lay under water, in the fea, 
and that thefe fhells owed their origin to “ fpume 
or froth,” which in a fhort time, afiumed a fun- 
gous appearance upon the wood : others affirmed 
that they were produced from the palms or fruits of 
a tree like the willow, which, when ripe, dropped 
off into the water, and became alive, &c. Trea- 
