The box was occupied by wrens for several years, but the entrance was never closed afterward, and I kept the sparrows from any further interference. In this connection I would say that, at least so far as the English sparrow is concerned, the male selects the site for the nest. When I shot the female the male soon returned with another mate, but when I shot the male the female did not return. The wren builds a very coarse nest, and fills the box nearly half full of sticks three or four inches long. As these sticks are carried in the birds’ bills by the middle, they would naturally strike the hole crosswise and could not enter, so when the birds get near the box they turn sideways and poke the sticks in end first, following in and arranging them afterward. The merganser is a fish duck nearly as large as our common domestic duck, and is known under the names of sheldrake and sawbill duck. The male is considerably larger than the female; he has a jet-black head, and the black extends down the neck for about two inches, where the color changes to a pure white, the line being as regular and distinct as the painting on the smokestack of a steamship. The body is generally white, with black markings on the wings and some black on the body; the breast is a beautiful salmon color when the bird is killed, but if mounted soon fades to a pure white. The male merganser in full plumage is one of our most beautiful birds. The female, besides being smaller, is of a grayish color, and the plumage and general appearance are entirely unlike the male, so that the sex can be easily determined even at a long distance. This bird is common on the Champlain and waters of the Adirondacks. Like all fish ducks, it has a long, sharp bill, which is serrated with sawtooth-shaped notches strongly suggesting teeth, a fact which has given this bird much interest to our evolutionary scientists. I have noticed a habit of this bird that I believe is entirely unique, and one I am surprised that our authorities on birds have not mentioned--that is, that the males are entirely migratory and the females are not. After the lakes and still waters freeze the mergansers go to the rivers which are open in some places on the rapids all winter. For more than twenty years I have seen female mergansers on the Au Sable River all winter, and I have frequently seen them on the other Adirondack rivers; but I have never seen a male merganser in the winter, and in the late fall the males and females gather in separate flocks, and when the male mergansers appear in the spring they are always in flocks by themselves.