Red Grouse This is another species that has diminished in number throughout Wales over the latter half of this century. Factors attributed to this include the lack of heather moorland management since World War II. Reserve numbers have increased slightly over the last ten years. During this time we have been carrying out an extensive cutting and burning programme on the moorland, creating a vast mosaic of heather stands of differing ages and structures, thus providing a good mixture of nesting places and food sources. Their main food sources are heather shoots, bilberry and insects. This bird is endemic to Britain, i.e. it is found nowhere else in the world. Across the entire reserve there are between 100 and 150 pairs, but due to their wile and elusive nature, they are very hard to see.