176 Bird-Lore corresponds to it. The transition to winter dress is less rapid, however, than the abrupt change from winter to summer, and the parti-colored plumage is most protective when the face of the country is partly brown and partly powdered white by the snow - squalls that herald the approach of winter. We have now followed the adult Ptarmigans in their molts through- out the year, and will find that they differ from other members of the SEASONAL PLUMAGES OF PTARMIGAN From specimens in the American Museum of Natural History. a, summer. ^, postnuptial or autumn c, winter. Grouse family only in their more extensive prenuptial molt and in their peculiar supplementary postnuptial molt. Let us now see what happens to the young birds. The chicks hatching in July or earlier are thickly covered with down. The juvenal plumage which follows the down is not unlike the nuptial dress of the adults, but the wing quills (except the two outer primaries, which are white) and the tail are
