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
Ptarmigan Tunnel Ptarmigan Tunnel The Ptarmigan Tunnel was built in 1930 through the Ptarmigan Wall at an elevation of in Glacier National Park, near Many Glacier. The tunnel allows hikers to avoid a strenuous climb over very steep terrain between Many Glacier and the Belly River valley. Two opposing steel jackhammers drilling from either side of the tunnel and a series of ten-hole rounds of dynamite gradually broke through the mountain in less than three months. A wide area, originally for guide and tourist horses, extends from each portal with a masonry retaining wall. Natural rock lines the interior walls. Heavy iron