The birds were going down through the broken-off top, and not by a hole through the leathery rind of the sides, for the bark was too tough for their beaks. They would drop into the top of the stub, pick up a wad of decayed wood and fly off to a dead limb of the pine. Here, with a jerk and a snap of their bills, they would scatter the punk in a shower so thin and far that I could neither hear it fall nor find a trace of it upon the dead leaves of the ground. This nest would never be betrayed by the workmen’s chips, as are the woodpeckers’ nest-holes. Between the pair there averaged three beakfuls of excavating every two minutes, one of the birds regularly shoveling twice to the other’s once. They looked so exactly alike that I could not tell which bird was pushing the enterprise; but I had my suspicions. It was Mrs. Chickadee! Mr. Chickadee was doing only part of his duty, and only half-heartedly at that! Hers was the real interest, the real anxiety. To be a Mr. Chickadee and show off! That’s the thing! I sat a long time watching the work. It went on in perfect silence, not a chirp, not the sound of a fluttering wing. The swamp along whose margin the birds were building had not a joyous atmosphere. Damp, dim-shadowed, and secret, it seemed to have laid its spell upon the birds. Their very color of gray and black was as if mixed out of the dusky colors of the swamp; their noiseless coming and going was like the slipping to and fro of small shadows. They were a part of the swamp--of its life, of its color, of its silence. They were children of the swamp, sharing its very spirit, and that sharing was their defense, the best protection that they could have had. It didn’t save their nest, however. They felt and obeyed the spirit of the Swamp in their own conduct, but the Swamp did not tell them where to build. Birds and animals have wonderful instinct, or family wisdom, but not much personal, individual wisdom. It was about three weeks later when I stopped again under the pine and found the birch stub in pieces upon the ground. Some strong wind had come, or some robber had been after the eggs, and had brought the whole house tumbling down. But this is not the fate of all such birch-bark houses. Now and again they escape; yet when they do it is always a matter for wonder.