224 THE ZOOLOGIST. 
Curlew down to the Dunlin,* which abound in this locality. Next to man, 
however, I am inclined to think that the Scoter, or Black Duck, is the worst 
enemy with which the cockle has to contend. A short time ago two of 
these birds were sent to me which had been shot in the neighbourhood 
of Grange, at the head of Morecambe Bay. I had the curiosity to examine 
the contents of their gizzards, and was surprised to find that they were 
both crammed with the shells of cockles, to the exclusion, apparently, of 
any other kind of food. Several of the shells were still entire, and measured 
half an inch in diameter. The rest, some of which had evidently been of 
much larger dimensions, had been broken up by the grinding process they 
had undergone. There could not have been less than the remains of a 
dozen cockles in each of the specimens I examined, and, supposing that 
a Scoter would eat from twenty to thirty in a day, a flock containing a 
thousand of these birds would devour in the course of a season (allowing 
due time for their absence at their breeding stations) not less than seven 
million cockles, amounting in weight to at least sixty tons. And yet a 
flock of a thousand Scoters does not represent a tithe of what may be seen 
in the bay at any time during the winter months. The mode in which 
these ducks procure their food is peculiar, and until I found it out I was at 
a loss to understand why they might so frequently be seen swimming in the 
shallow water at a distance of from fifty to a few hundred yards from the 
water's edge. As the rising tide covers the banks, the sand, for the depth 
of an inch or two, is gradually stirred up until it becomes a semi-liquid 
mass. The cockles, which, unlike mussels, are not attached to any foreign 
substance, lie at about this depth below the surface, and the ducks, swimming 
up on the advancing flood find no difficulty in diving or reaching down and 
extracting them from their sandy bed. ‘The same tidal action tends, 
doubtless, to disperse the spat given off by the parent cockle during the 
breeding season, and explains how they are able to move (whether of their 
own free will or not | am unable to say) from place to place. No doubt, 
too, it is in this way that the shell-fish which live beneath the sand obtain 
their food—a fact which finds support in the evidence of one of the 
witnesses, who alluded to the mortality produced among the cockles by 
severe frosts. Thus far the case against the birds appears as black as 
possible; but, on the other hand, we are met by the unanswerable 
argument that thirty years ago the birds were ten times as numerous 
as they are at present; and yet, according to the evidence of the opponents 
of sea-birds, the shell-fish were also far more plentiful than is now the case. 
These are facts which it is hard to reconcile, and we must be content to 
suppose that in those days there was room enough for the birds, the 
cockles, and their human enemies to live without the weaker species being 
* We have often found cockles, sometimes of large size, in the stomach of the 
Curlew, but never in that of the Dunlin.—Ep. 
