The downy is not forced to seek the sun and warmth and the inexhaustible food of the Tropics, for the woodlands of New England and southeastern Canada are stored with food that, with a roosting hole, enables the bird to withstand the severest winter. But this food is limited; the insects that have been multiplying all summer, thus adding continually to the woodpeckers’ supply of food, stop multiplying when the frosts come, and will add no more until spring. The downy is not a bird that ranges widely in search of food; moreover, for protection against the weather it is held to the vicinity of its roosting hole. Therefore each bird, in order to be sure of sufficient food for itself during the cold months, must maintain dominion over a territory large enough to support it through the winter. Thus it comes about that in autumn the downy _does_ perforce change its habits, or rather its attitude toward other birds of its species. The families disperse, and until the next breeding season each individual becomes a solitary bird, living in a restricted region, which it defends against trespass, resenting and repelling the approach of any other downy woodpecker. This reversal of attitude or character--the change from a member of a family to an anchorite in fall, and back again in spring--takes place gradually, we may suppose, and not exactly at the same time in every bird. Hence one bird meeting another in autumn, while the change is in progress, may underestimate the degree to which it has drawn away from its fellows, or, in the spring, may overestimate the amount of cordiality that has returned to the wintering anchorite. This lack of understanding may give rise to behavior difficult or impossible for us to interpret. Sometimes the relationship between two downies is clear enough, as when, on September 20, 1910, I saw a male fly repeatedly at a female in a menacing way and drive her off; and when on November 3, 1935, I saw a female bird fly toward a male, which was perched near a hole in an electric-light pole, from which he did not retire, as a perched bird commonly does when approached by a bird on the wing, but held his ground while she flew away; and when Lewis O. Shelley (MS.) tells of a female bird “rushing with antagonistic attitude at her two daughters” and also driving off her granddaughters whenever they invaded her winter territory in autumn, all these birds being identified by bands.