Willow ptarmigan complicated changes in plumage several times a year and the differing colour and pattern of the summer plumage: The willow ptarmigan often hybridises with the black grouse ("Tetrao tetrix") and the hazel grouse ("Tetrastes bonasia") and occasionally with the western capercaillie ("Tetrao urogallus"), the spruce grouse ("Falcipennis canadensis") and the rock ptarmigan ("Lagopus muta"). During the Pleistocene, the willow ptarmigan widely occurred in continental Europe. Authors who recognize paleosubspecies have named the Pleistocene willow ptarmigan "L. l. noaillensis" (though the older name "medius" might be the correct one). These marginally different birds are said to have gradually changed from the
USS Ptarmigan (AM-376) USS Ptarmigan (AM-376) USS "Ptarmigan" (AM-376) was an acquired by the United States Navy for the dangerous task of removing mines from minefields laid in the water to prevent ships from passing. She was the only U.S. Navy ship named for the ptarmigan, a grouse with feathered feet, found in northern regions. "Ptarmigan" was laid down 9 March 1944 by Savannah Machine and Foundry Co., Savannah, Georgia; launched 15 July 1944, sponsored by Miss Jeanne Summerlin; and commissioned 15 January 1945, Lt. Alexander B. Barrett in command. "Ptarmigan" departed for the Pacific Ocean 1 May 1945. Following duty off Hawaii