Redpolls arrive to the forested tundra in two waves: first ones that winter in the forested tundra, then those wandering in the middle latitudes. Considerable oscillations in nesting density are typical of redpolls. High rates of the growth and development of embryos and nestlings are revealed. This allows them to rear two or sometimes three broods. After the brood break up, this being associated with the beginning of molting, adults partly remain within the nesting area, but partly migrate to other localities for the molting period. The species is adapted to the photoperiodic conditions of high latitudes, as redpolls arrive towards the Polar circle with mature gonads, show high rates of molting during a 24-hour daytime, are capable of partly combining the post-nuptial molt with rearing the second brood, and the yearlings acquire migration conditions rather early.