Unit 1 [PDF] - Wisconsin Department of Natural Resources

Common sets for beaver:
• Scent-mound
• Open-water
• Under-Ice Bait
• Runway
• Channel
• Cable snare
Recommended traps and trapping
systems:
• #330 body-grip
• #3 foot-hold
• #4 foot-hold
• #5 foot-hold
• #14 foot-hold
• Cable snares
Chapter 4 - Wisconsin’s Furbearer Resource
Normally, only one female per colony usually gives birth, although multiple
females can give birth in the same year. In the spring, before the young are
born, the two-year-old beaver are normally forced from the colony to disperse
and establish their own colony. It is these dispersers that can be captured quite
easily using scent mounds set in the early spring along larger streams. This
movement continues into early summer.
Beaver are one of a few animals capable of manipulating their environment,
and are an important part of the ecosystem. Their dams create fish and wildlife
habitat, reduce erosion and improve water quality. Conversely, the animal
sometimes damages valuable trees and crops or causes flooding that affect
farmlands, wild rice beds, roads, and residential areas.
They build dams on streams and small flowages to create a pond with a stable
water level. The dam is constructed of sticks and mud, mixed with a few rocks
if available. The upstream, or pond side, is smoothly plastered with mud. Contrary
to popular belief, the beaver does not use its tail as a trowel to apply mud
to the dam. All members of the family, except kits, help keep the dam in repair.
A lodge varies in size from 6 to 40 feet in diameter depending on the number
of beaver in the colony, built of sticks, tree limbs and mud, and contains a nest
chamber which has its entrance underwater. Burrows are often dug into the
banks of the pond and used as resting areas. Some older male beaver, referred
to as “bachelors”, live alone and do not have a dam. When suitable banks are
present, such as on large rivers or drainage ditches, beaver will construct a bank
den instead. The entrance to the den is underwater and the tunnel leading to it
may be 12-15 feet long.
In the spring and summer, beaver feed mainly on small twigs and aquatic
plants such as water lily, cattail roots, sedges, and on corn stalks or other
terrestrial plants found near the waters edge. Beginning in late August, tree
and brush cutting activity increases dramatically, and a food pile, or cache, is
constructed near the lodge by anchoring branches, shrubs and small trees in
the bottom of the pond. This activity peaks at the time of leaf fall. This cache,
which usually consists of aspen, alder, willow, and birch, provides the green
bark which serves as the late fall and winter food supply.
Beaver are very territorial and force away any beaver which does not belong
to the colony. The adults mark their territory by creating scent mounds, or
“castor mounds”, on the bank or dam and depositing their scent, or castor, on
these mounds.
Wisconsin Trapper Education Manual 24