THE PERSISTENT BEAVER
I saw a forest fire sweeping down upon the Broken Tree Beaver colony,
and I knew that the inhabitants could take refuge in their earthy,
fire-proof houses in the water. Their five houses were scattered in
the pond like little islands or ancient lake dwellings. A vigorous
brook that came down from the snows on Mount Meeker flowed through the
pond. Towering spruce trees encircled its shores.
The beavers survived the fiery ordeal, but their near-by and
prospective winter food-supply was destroyed. This grove of aspen and
every deciduous tree that might have furnished a bark food-supply was
consumed or charred by the fire.
Instead of moving, the colony folks spent a number of days clearing
the fire wreckage from their pond. With winter near and streams
perilously low for travelling, it probably was unwise to go elsewhere
and try to build a home and gather a harvest.
One night, early in October, the colonists gnawed down a number of
aspens that had escaped the fire. These were in a grove several
hundred feet down stream from the pond. A few nights later they
commenced to drag the felled aspens up stream into their pond. This
was difficult work, for midway between the grove and the pond was a
waterfall. The beaver had to drag each aspen out of the water and up a
steep bank and make a portage around the falls.
The second night of this up-stream transportation a mountain lion had
lain in wait by the falls. Tracks and marks on the muddy slope showed
that he had made an unsuccessful leap for two beavers on the portage.
The following morning an aspen of eighty pounds’ weight which two
beavers had evidently been dragging was lying on the slope. The lion
had not only missed, but on the muddy slope he slipped and received a
ducking in the deep water-hole below.
Transportation up stream was stopped. The remainder of the felled
aspens were piled into a near-by “safety pond.” A shallow stream which
beavers use for a thoroughfare commonly has in it a safety pond which
they maintain as a harbour, diving into it in case of attack. Usually
winter food is stored within a few feet of the house, but in this case
it was nearly six hundred feet away. In storing it in the safety pond,
the beavers probably were making the best of a bad situation.
Two days after the attack from the lion the beavers commenced cutting
trees about fifty yards north of their pond. The beavers took pains to
clear a trail or log road over which to drag their felled trees to the
pond. Two fallen tree trunks were gnawed into sections, and one
section of each rolled out of the way. A two-foot opening was cleared
through a tongue of willows, and the cuttings dragged into the pond
and placed on top of the food-pile.
One morning a number of abandoned cuttings along this cleared way told
that the harvesters had been put to flight. No work was done during
the three following nights. Tracks in the mud showed that a lion was
prowling about.
Pioneer dangers and hardships are the lot of beaver colonists. The
history of every old beaver house is full of stirring interest. The
house and the dam must have constant care. Forest fires or other
uncontrollable accidents may force the abandonment of the colony at a
time when the conditions for travelling are deadly, or when travelling
must be done across the country. A score may leave the old home, but
only a few survive the journey to the new home site.
The Broken Tree colonists continued the harvest by cutting the
scattered aspens along the stream above the pond. A few were cut a
quarter of a mile up stream. Before these could be floated down into
the pond it was necessary to break a jam of limbs and old trees that
had collected against a boulder. The beaver gnawed a hole through the
jam. One day a harvester who ventured far up a shallow brook was
captured by a grizzly bear. During this unfortunate autumn it is
probable that others were lost besides these mentioned.
Harvest-getting ended by the pond and the stream freezing over. It is
probable that the colonists had to live on short rations that winter.
One winter day a beaver came swimming down into the safety pond. I
watched him through the ice. He dislodged a small piece of aspen from
the pile in the bottom of the pond and with it went swimming up stream
beneath the ice. At the bottom of the icy falls I found a number of
aspen cuttings with the bark eaten off. While examining these, I
discovered a hole or passageway at the bottom of the falls. This
tunnel extended through the earth into the pond above. This
underground portage route enabled the beavers to reach their supplies
down stream.
The fire had killed a number of tall spruces on the edge of the pond,
and their tall half-burned mats swayed threateningly in the wind. One
night two of the dead spruces were hurled into the pond. The smaller
one had fallen across a housetop, but the house was thick-walled and,
being frozen, had sustained the shock which broke the spruce into
sections. The other fallen tree fell so heavily upon two of the houses
that they were crushed like shells. At least four beavers were killed
and a number injured.
Spring came early, and the colonists were no doubt glad to welcome it.
The pond, during May and June, was a beautiful place. Grass and wild
flowers brightened the shore, and the tips of the spruces were thick
with dainty bloom. Deer came up from the lowlands and wild sheep came
down from the heights. The woods and willows were filled with happy
mating birds. The ousel built and sang by the falls near which it had
wintered. Wrens, saucy as ever, and quiet bluebirds and numbers of
wise and watchful magpies were about. The Clarke crows maintained
their noisy reputation, and the robins were robins still.
One May morning I concealed myself behind a log by the pond, within
twenty feet of the largest beaver house. I hoped to see the young
beavers. My crawling behind a log was too much for a robin, and she
raised such an ado concerning a concealed monster that other birds
came to join in the hubbub and to help drive me away. But I did not
move, and after two or three minutes of riot the birds took themselves
off to their respective nesting-sites.
Presently a brown nose appeared between the house and my hiding place.
As a mother beaver climbed upon one of the spruce logs thrust out of
the water, her reflection in the water mingled with spruces and the
white clouds in the blue field above. She commenced to dress her
fur--to make her toilet. After preliminary scratching and clawing with
a hind foot, she rose and combed with foreclaws; a part of the time
with both forepaws at once. Occasionally she scratched with the double
nail on the second toe of the hind foot. It is only by persistent
bathing, combing, and cleaning that beavers resist the numerous
parasites which thick fur and stuffy, crowded houses encourage.
A few mornings later the baby beavers appeared. The mother attracted
my attention with some make-believe repairs on the farther end of the
dam, and the five youngsters emerged from the house through the water
and squatted on the side of the house before I saw them. For a minute
all sat motionless. By and by one climbed out on a projecting stick
and tumbled into the water. The others showed no surprise at this
accident.
The one in the water did not mind but swam outward where he was caught
in the current that started to carry him over the dam. At this stage
his mother appeared. She simply rose beneath him. He accepted the
opportunity and squatted upon her back with that expressionless face
which beavers carry most of the time. There are occasions, however, on
which beavers show expression of fear, surprise, eagerness, and even
intense pleasure. The youngster sat on his mother’s back as though
asleep while she swam with him to the house. Here he climbed off in a
matter-of-fact way, as though a ride on a ferry-boat was nothing new
to him.
A few weeks later the mother robin who had become so wrought up over
my hiding had times of dreadful excitement concerning the safety of
her children. If anything out of the usual occurs, the robin insists
that the worst possible is about to happen. This season the mother
robin had nested upon the top of the beaver house. This was one of the
safest of places, but so many things occurred to frighten her that it
is a wonder she did not die of heart disease. The young robins were
becoming restless at the time the young beavers were active. Every
morning, when on the outside of the beaver house each young beaver
started in turn as though to climb to the top, poor Mother Robin
became almost hysterical. At last, despite all her fears, her entire
brood was brought safely off.
During the summer, a majority of the Broken Tree beavers abandoned the
colony and moved to other scenes. A number built a half-mile down
stream, while the others, with one exception, travelled to an
abandoned beaver colony on the first stream to the north. Overland
this place was only half a mile from the Broken Tree, but by water
route, down stream to the forks then up the other stream to the
colony, the distance was three miles. This was an excellent place to
live, and with but little repair an old abandoned dam was made better
than a new one. All summer a lone beaver of this colony rambled about.
Once he returned to the Broken Tree colony. Finally, he cast his lot
with the long-established colony several miles down stream.
Late this summer a huge landslide occurred on the stream above the
Broken Tree pond. The slide material blocked the channel and formed a
large, deep pond. From this dam of débris and the torn slope from
which it slipped came such quantities of sediment that it appeared as
though the pond might be filled. Every remaining colonist worked day
and night to build a dam on the stream just above their pond. They
worked like beavers. This new pond caught and stopped the sediment. It
was apparently built for this purpose.
The colonists who remained repaired only two of the five houses, and
between these they piled green aspen and willow for winter food. But
before a tree was cut they built a dam to the north of their home.
Water for this was obtained by a ditch or canal dug from the stream at
a point above the sediment-catching pond. When the new pond was full,
a low grassy ridge about twenty feet across separated it from the old
one. A canal about three feet wide and from one to two feet deep was
cut through the ridge, to connect the two ponds. The aspens harvested
were taken from the slope of a moraine beyond the north shore of the
new pond. The canal and the new pond greatly shortened the land
distance over which the trees had to be dragged, and this made
harvesting safer, speedier, and easier.
Occasionally the beavers did daytime work. While on the lookout one
afternoon an old beaver waddled up the slope and stopped by a large
standing aspen that had been left by the other workers. At the very
bottom this tree was heavily swollen. The old beaver took a bite of
its bark and ate with an expressionless face. Evidently it was good,
for after eating the old fellow scratched a large pile of trash
against the base of the tree, and from this platform gnawed the tree
off above the swollen base. While he was gnawing a splinter of wood
wedged between his upper front teeth. This was picked out by catching
it with the double nails of the second toe on the right hind foot.
This aspen was ten inches in diameter at the point cut off. The
diameter of trees cut is usually from three to six inches. The largest
beaver cutting that I have measured was a cottonwood with a diameter
of forty-two inches. On large, old trees the rough bark is not eaten,
but from the average tree which is felled for food all of the bark and
a small per cent of the wood is eaten. Rarely will a beaver cut dead
wood, and only in emergencies will he cut a pine or a spruce.
Apparently the pitch is distasteful to him.
One day another beaver cut a number of small aspens and dragged these,
one or two at a time, to the pond. After a dozen or more were
collected, all were pushed off into the water. Against this small raft
the beaver placed his forepaws and swimming pushed it to the food-pile
near the centre of the old pond.
At the close of harvest the beavers in Broken Tree colony pond
covered their houses above waterline with mud, which they dredged from
the pond around the foundations of their houses. Sometimes this mud
was moved in their forepaws, sometimes by hooking the tail under and
dragging it between their hind legs. Then they dug a channel in the
bottom of the pond, which extended from the houses to the dam.
Parallel with the dam they dug out another channel; the excavated
material was placed on the top of the dam. They also made a shallow
ditch in the bottom of the pond that extended from the house to the
canal that united the two ponds.
The following summer was a rainy one, and the pond filled with
sediment to the height of the dam. Most of this sediment came from the
landslide débris or its sliding place. The old Broken Tree colony was
abandoned.
Different from most animals, the beaver has a permanent home. The
beaver has a strong attachment, or love, for his old home, and will go
to endless work and repeatedly risk dangers to avoid moving away. He
will dig canals, build dams, or even drag supplies long distances by
land through difficult and dangerous places that he may live on in the
old place. Here his ancestors may have been born and here he may spend
his lifetime. In most cases, however, a colony is not continuously
occupied this long. A flood, fire, or the complete exhaustion of food
may compel him to move and seek a new home.
In abandoning the Broken Tree pond, one set of dwellers simply went up
stream and took possession of the pond which the landslide had formed.
Here they gathered supplies and dug a hole or den in the bank but they
built no house. An underground tube or passageway connected this den
with the bottom of the pond.
The remainder of the colonists started anew about three hundred feet
to the north of the old pond. Here a dam about sixty feet long was
built, mostly of mud and turf excavated from the area to be filled
with water for their pond. They commenced their work by digging a
trench and piling the material excavated on the lower side--the
beginning of the dam. This ditch was then widened and deepened until
the pond was completed. All excavated material was placed upon the
dam.
Evidently the site for the house, as well as for the pond, was
deliberately selected. The house was built in the pond alongside a
spring which in part supplied the pond with water. The supply of
winter food was stored in the deep hole from which the material for
the house was excavated. The water from the spring checked freezing
near the house and the food-pile, and prevented the ice from
troubling the colonists. Beavers apparently comprehend the advantage
of having a house close to a spring. This spring commonly is between
the main house entrance and the winter food-pile.
Their pond did not fill with sediment. As the waters came entirely
from springs they were almost free of sediment. After eighteen years
of use there was but a thin covering of sediment on the bottom of the
pond. Neither brook nor stream entered this pond. Was this pond
constructed in this place for the purpose of avoiding sediment? As
beavers occasionally and with much labour build in a place of this
kind, when there are other and easier near-by places in which to
build, it may be that this pond was placed here because it would
escape sediment. This was the founding of the Spruce Tree colony. It
is still inhabited.