170 SPRING. 



feeding. We have never seen the carcass of a crow 

 fastened by the bill under the shell of a limpet, and 

 therefore we cannot positively assert that this is ever 

 the fate either of ravens or of rooks ; neither had we 

 ever the means of examining the lever power that a 

 crow can exert with its bill against the adhesive power 

 of the limpet ; and therefore we cannot absolutely deny 

 the fact. The limpet (patella vulgaris) adheres to the 

 rock by the foot ; and the adhesive power is only the 

 pressure of the atmosphere upon that, which, on a 

 pretty large one, may be about fifteen pounds; and 

 possibly that may be more than a crow can, under 

 some circumstances, raise with the bill ; though it may 

 often be seen tugging from side to side, arid ultimately 

 drawing from the ground roots that, by us, would need 

 a greater force. As to the lifting of whelks into the 

 air, and letting them fall upon the rocks, that is a very 

 common operation ; we have seen the rocks thick with 

 the broken shells, so recent that it must have been 

 done during the tide when the crows were at work ; 

 and we have actually seen the shells drop and be dashed 

 to pieces, though the birds that were then fishing were 

 not rooks but crows. It is by no means improbable 

 that some of the tribe, the carrion crow and the raven 

 for instance, may dig in the sand for the crabs and 

 other shell fish that bury themselves there : we have 

 often corns upon them at work within flood mark, where 

 there was nothing upon the surface, for many miles, 

 but sand ; and therefore their object must have been 

 to find out something that burrowed. 



Although, as has been said, the rook be generally 

 the friend and fellow labourer with man in clearing the 



