The name for the unique patchwork colouration of many herding dogs such as the border collie and Australian Shepherd, as well as a generalized name for dogs of this colouration. In usage, the word is analagous to the use of calico when describing a cat. The American Kennel Club judges some breeds of dog based on the inclusion or exclusion of certain colors from their merle, which can include red, brown, black, sable, grey, and blue(!). Merles that are of unacceptable colouration are still loved and prized all around the world, but particularly in the British Isles, where they are cherished farm dogs and friends. Jimmy Page said it best in Bron-Y-Aur Stomp: "Ain't no companion like a blue-eyed merle!"