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70 Yet the importance of heather in building up the birds for the approach of winter cannot be exaggerated, and there is little doubt that in a bad heather year all the young birds suffer, while even in a good heather year the later broods will be permanently handicapped as regards physique and disease-resisting power if they have missed the best food months.

The most noteworthy fact brought out by Table II. is that Grouse appear to require a larger quantity of food in the winter months from December to March, than in the spring, summer and autumn months from April to November. It is, of course, true that in a bad heather year Grouse may find substitutes for their staple diet. Of these substitutes blackberry is undoubtedly the most valuable, as may be seen by reference to Tables III. and IV.; - but in many districts blackberry does not grow upon the moors, and in no case is it so reliable a winter food as good heather. Other substitutes for heather are rush-heads, crowberry, bog myrtle buds, seeds of P. tormentilla fern leaves, bog cranberry leaves, flowers of Erica tetralix and Erica cinerea, moss spore capsules, sheep sorrel leaves and seeds, insects, and oats. On pp. 83–87 will be found a list of the vegetable foods eaten from time to time by the Red Grouse, with illustrations of some of the plants referred to.

The summer substitutes for heather, while interesting as showing the wide range of the Grouse's diet when many varieties of food are available, cannot be considered of great importance to the health of the adult bird, for if the