the rivers and fixing the soil,--he
plays an important part, and if he and the forest had their way with
the water-supply, floods would be prevented, streams would never run
dry, and a comparatively even flow of water would be maintained in
the rivers every day of the year.

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 inst