A number of beaver establishing a colony made one of the most interesting exhibitions of constructive work that I have ever watched. The work went on for several weeks, and I spent hours and days in observing operations. My hiding-place on a granite crag allowed me a good view of the work,--the cutting and transportation of the little logs, the dam-building, and the house-raising. I was close to the trees that were felled. Occasionally, during the construction work of this colony, I saw several beaver at one time cutting trees near one another. Upon one occasion, one was squatted on a fallen tree, another on the limb of a live one, and a third upon a boulder, each busy cutting down his tree. In every case, the tail was used for a combination stool and brace. While cutting, the beaver sat upright and clasped the willow with fore paws or put his hands against the tree, usually tilting his head to one side. The average diameter of the trees cut was about four inches, and a tree of this size was cut down quickly and without a pause. When the tree was almost cut off, the cutter usually thumped with his tail, at which signal all other cutters near by scampered away. But this warning signal was not always given, and in one instance an unwarned cutter had a narrow escape from a tree falling perilously close to him. Before cutting a tree, a beaver usually paused and appeared to look at its surroundings as if choosing a place to squat or sit while cutting it down; but so far as I could tell, he gave no thought as to the direction in which the tree was going to fall. This is true of every beaver which I have seen begin cutting, and I have seen scores. But beavers have individuality, and occasionally I noticed one with marked skill or decision. It may be, therefore, that some beaver try to fell trees on a particular place. In fact, I remember having seen in two localities stumps which suggested that the beaver who cut down the trees had planned just how they were to fall. In the first locality, I could judge only from the record left by the stumps; but the quarter on which the main notch had been made, together with the fact that the notch had in two instances been made on a quarter of the tree where it was inconvenient for the cutter to work, seemed to indicate a plan to fell the tree in a particular direction. In the other locality, I knew the attitude of the trees before they were cut, and in this instance the evidence was so complete and conclusive that I must believe the beaver that cut down these trees endeavored to get them to fall in a definite direction. In each of these cases, however, judging chiefly from the teeth-marks, I think the cuttings were done by the same beaver. Many observations induce me to believe, however, that the majority of beaver do not plan how the trees are to fall.