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 (sternwheeler) Ptarmigan (sternwheeler) Ptarmigan was a sternwheel steamboat that operated in British Columbia on the Columbia River from 1903 to 1909. "Ptarmigan" was built at Golden, BC and was the last vessel built for the Upper Columbia Navig. & Tramway Co., of which Capt. Frank P. Armstrong was the principal owner and manager. "Ptarmigan"'s engines were over 60 years old, and had been originally built for a ferry crossing the St. Lawrence River. The engines had been previously installed in two other sternwheelers on the upper Columbia River, specifically the first "Duchess", and the second "Duchess". The blunt-ended bow of "Ptarmigan"