224 
HAVENS* 
usually do in returning to their rookery; and about 
a week afterwards, twenty-six were observed by the 
same party flying to the southward. There is reason, 
however, to believe that these assemblages of Ravens 
ought not to be admitted as proofs of their being, 
under any circumstances or seasons of the year, really 
gregarious ; that is, naturally disposed to associate in 
flocks, but is rather to be attributed to the attraction 
of distant food, which, if beyond the reach of vision, 
they can, by some unknown faculty, discover at great 
distances. It can scarcely be by scent, for in those 
northern regions, when all is calm and quiet, and 
the severity of frost rapidly destroys all the effluvia 
of dead matter, still troops of Ravens, within an in- 
credible short time after the slaughter of an animal, 
will be seen advancing from all points to this common 
centre of attraction, like the Vultures of which we 
have before spoken, though, at the time, not a single 
bird was to be seen on the wing. This sagacity in 
discovering their prey is, indeed, too well-known in 
some less favoured spots, where food is scarce for man 
as well as beast or bird, and the Raven’s presence is 
looked upon as a perfect nuisance. Thus, in the He- 
brides, Shetland, Ferroe Islands, and Iceland, they are 
sadly destructive. Nothing escapes them; they watch 
the Wild Duck to her nest, and drive her from her 
eggs ; they pounce upon fish like the Fishing Hawks ; 
they attack the ewe as well as the lamb, and fixing 
on a galled horse, feed on his flesh even while living. 
It is not, therefore, surprising, that laws are made for 
their extirpation. Accordingly, in the Ferroe Islands, 
every man, who is in a condition to catch fish, must 
deliver, annually, the bill of one Raven, or those of 
