In spite of the exposure this must be a warm bed. The walls are thick and well plastered with mud, and are packed inside with fine, shredded bark which the mouse himself has pulled from the dead chestnut limbs, or, more likely, has taken from a deserted crow's nest. The whole is thatched with a roof of shredded bark, so neatly laid that it sheds water perfectly. The entrance is on the side, just over the edge of the original structure, but so shielded by the extending roof that the rain and snow never beat in. The thrushes did their work well; the nest is securely mortised into the forking branches; and Whitefoot can sleep without a tremor through the wildest winter gale. Whenever the snow falls lightly a high white tower rises over the nest; and then the little haycock, lodged in the slender limbs so far above our heads, is a very castle indeed. High over the nest of the white-footed mouse, in the stiffened top of a tall red oak that stands on the brow of the hill, swings another winter bed. It is the bulky oak-leaf hammock of the gray squirrel. A hammock for a winter bed? Is there anything snug and warm about a hammock? Not much, true enough. From the outside the gray squirrel's leaf bed looks like the coldest, deadliest place one could find in which to pass the winter. The leaves are loose and rattle in the wind like the clapboards of a tumble-down house. The limb threatens every moment to toss the clumsy nest out upon the storm. But the moorings hold, and if we could curl up with the sleeper in that swaying bed, we should rock and dream, and never feel a shiver through the homespun blankets of chestnut bark that wrap us round inside the flapping leaves. Be it never so cozy, a nest like this is far from a burrow--the bed of a fat, thick-headed dolt who sleeps away the winter. A glance into the stark, frozen top of the oak sends over us a chill of fright and admiration for the dweller up there. He cannot be an ease-lover; neither can he know the meaning of fear. We should as soon think of a sailor's being afraid of the shrieking in the rigging overhead, as of this bold squirrel in the tree-tops dreading any danger that the winter winds might bring. There are winters when the gray squirrel stays in the hollow of some old tree. A secure and sensible harbor, this, in which to weather the heavy storms, and I wonder that a nest is ever anchored outside in the tree-tops. The woodsmen and other wiseacres say that the squirrels never build the tree-top nests except in anticipation of a mild winter. But weather wisdom, when the gray squirrel is the source, is as little wise as that which comes from Washington or the almanac. I have found the nests in the tree-tops in the coldest, fiercest winters. [Illustration: "From his leafless height he looks down into the Hollow."]