There are few of our land-birds that flock together in summer, and few that are solitary in winter,--none that I recollect, except birds of prey. And not only do birds of the same kind associate, but certain species are almost always found together. Thus, the chickadee, the golden-crested wren, the white-breasted nuthatch, and, less constantly, the brown creeper and the downy woodpecker, form a little winter clique, of which you do not often see one of the members without one or more of the others. No sound in nature more cheery and refreshing than the alternating calls of a little troop of this kind echoing through the glades of the woods on a still, sunny day in winter: the vivacious chatter of the chickadee, the slender, contented pipe of the gold-crest, and the emphatic, business-like _hank_ of the nuthatch, as they drift leisurely along from tree to tree. The winter seems to be the season of holiday enjoyment to the chickadee, and he is never so evidently and conspicuously contented as in very cold weather. In summer he withdraws to the thickets, and becomes less noisy and active. His plumage becomes dull, and his brisk note changes to a fine, delicate _pee-peh-wy_, or oftenest a mere whisper. They are so much less noticeable at this season that one might suppose they had followed their gold-crest companions to the North, as some of them doubtless do, but their nests are not uncommon with us. Fearless as the chickadee is in winter,--so fearless, that, if you stand still, he will alight upon your head or shoulder,--in summer he becomes cautious about his nest, and will desert it, if much watched. They build here, generally, in a partly decayed white-birch or apple-tree, excavating a hole eighteen inches or two feet deep,--the chips being carefully carried off a short distance, so as not to betray the workman,--and lining the bottom of it with a felting of soft materials, generally rabbits' fur, of which I have taken from one hole as much as could be conveniently grasped with the hand.