Which bird is the largest member of the grouse family?

The western capercaillie, also known as the wood grouse, heather cock, or just capercaillie, is the largest member of the grouse family. The largest known specimen, recorded in captivity, had a weight of 7.2 kg (16 lb).

Male and female western capercaillie can easily be differentiated by their size and colouration. The cock is much bigger than the hen. It is one of the most sexually dimorphic in size of living bird species, only exceeded by the larger types of bustards and a select few members of the pheasant family.

Found across Eurasia, this ground-living forest bird is renowned for its mating display. The worldwide population is in the category "least concern" of the IUCN, but the populations of Central Europe are declining and endangered or already extinct.