Why do ptarmigans feathers change colour?
To be specific, the feathers don’t change color. Once the feather is made, it has only that one color. There are some birds, like starlings, that appear to be speckled at one time in the year, and they change color as the tip of their feathers are worn away. The bird itself changes colors by changing its feathers. Ptarmigans molt their feathers and the new feathers that come in have a different color, depending on the season. White feathers during the winter conceal the animal from predators, while the brownish patterned feathers are more suitable for concealment when the snow melts.
