Coloration evidence for natural selection J. Bowler wrote that Darwin's theory In his 1889 book "Darwinism", the naturalist Alfred Russel Wallace considered the white coloration of Arctic animals. He recorded that the Arctic fox, Arctic hare, ermine and ptarmigan change their colour seasonally, and gave "the obvious explanation", that it was for concealment. The modern ornithologist W. L. N. Tickell, reviewing proposed explanations of white plumage in birds, writes that in the ptarmigan "it is difficult to escape the conclusion that cryptic brown summer plumage becomes a liability in snow, and white plumage is therefore another cryptic adaptation." All the same, he notes, "in spite
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