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
Ptarmigan (sternwheeler) allowed the vessel to be more capable of pushing barges, which increased the vessel's utility and effective cargo capacity. "Ptarmigan" was placed on the Columbia River route that began at Golden and ran south, at least during high water, to Columbia Lake, the ultimate source of the Columbia River. In 1903, soon after completion, "Ptarmigan" was sold to the Columbia River Lumber Company, which hired Armstrong to manage its steamboat operations. In 1907 "Ptarmigan" hit a snag and sank (A snag is a sunken log jammed in the river bottom but sticking up through the water to just below the