Probably the consumption of other foods, which are classed under "various," and have already been enumerated, varies in the same way chiefly with local relative abundance, as, for example, in Perthshire, where "various" rises to 53 per cent.; Ayrshire, where it reaches 47 per cent.; and Derbyshire, where it reaches 40 per cent, of all foods taken.
Individual taste plays a large share in the food statistics of Grouse. One may find, for example, one bird eating largely of fern leaf, another of bog myrtle buds, another of nothing but rush heads or tormentilla seed. In one case, where two birds were killed with a "right and left" in a Grouse drive it was found that one had filled his crop with heather shoots, the other with blaeberry leaf buds, yet both birds had come off the same beat. Occasionally one finds that even an adult bird has eaten scores of small black gnats. The flower of Calluna is varied occasionally by the flower of Erica tetralix, or ripe cluster berries, or spore capsules of several mosses, or leaves of the cloudberry.
The interest of Table IV. centres on the first item, "Heather Shoots," for the figures prove conclusively, if proof were required, that, except on Heather
shoots the
solo diet
in February
and
March. favoured moors where blaeberry abounds, heather shoots and nothing but heather shoots constitute the diet of the Grouse during February and March — the fact that the February column shows 7 per cent. of March "various" was due to one bird's crop being almost entirely filled with crowberry leaves, a quite unusual diet; the "various" consumed by other specimens examined for that month only amounted to 1⁄3 per cent.
It is obvious, therefore, that in February, March, and April the question of food becomes a critical one, for if the heather fails the Grouse must suffer either by direct starvation, or what is much more dangerous, by being forced to crowd too closely on to the few small areas where good winter heather is to be obtained.
Although we have no evidence from any one of the hundreds of Grouse crops examined that true frosted heather is ever eaten, the heather which actually filled the majority of the winter crops varied greatly in its value as a food. It could often be seen that the birds had been hard put to it to fill their crops at all, perhaps from stress of weather, or possibly because of excessive or deficient burning or an overstock of sheep, or for some other less obvious reason.
The mere fact that the crops of many birds contain old heather is enough
