Every fall Ruffed Grouse (Bonasa umbellus) grow skin-like fringes called pectinations on either side of each toe. They serve as snowshoes, helping grouse stay on top of the snow when walking, as well as cling to icy branches while eating the buds of poplars and other trees in the winter. In the spring grouse shed these adaptive fringes.
Ornithological texts describe these growths as appearing in the fall, but usually do not specify exactly when they develop. A recent look at a road-killed grouse’s foot (photo) showed that pectinations have begun to develop, but have not completed their growth. The pectinations shown here will double their length by the time snow flies.