March 2021 - 35

and Fish utilizes a handful of small, portable trailers
to temporarily keep trapped beavers before relocating
them. The concept dates back to the 1990s when Mark
McKinstry studied and conducted beaver transplant
work around the state and had papers published about
his work while he was at the University of Wyoming.
Altermatt isn't the only Game and Fish biologist
doing this work around the state. When first starting
the effort, he borrowed equipment from Travis Cundy,
Game and Fish aquatic habitat biologist in Sheridan.
But when Altermatt got the equipment, he saw a need
for some trailer tweaks.
" When Jerry borrowed my equipment he remarked,
'Boy, there's a lot of room for improvement', " Cundy
said.
Beavers need three things from their temporary
housing until being relocated: water, food and a protective lodge. With these things in mind, Altermatt set
out to design and build his trailer so it would reduce
stress on the animals and make them as comfortable
as possible until they were relocated in the wild.
Altermatt made a few modifications to his 5-by-10foot trailer. Much of it has a cage-like look. The trailer
is made of aluminum, which is expensive but lighter,
more portable and resistant to corrosion. He made
the feeding area level with the top of the 100-gallon
water tank for easier access. The tank is hinged on
one side so that it can be flipped over the side of the
trailer to dump out debris and waste after draining the
water each day. Next to the feeding area is a lodge box
beavers use for shelter. Altermatt said it duplicates a
bank den or stick lodge in the wild, which is enclosed.
That box can be removed and put in the back of his
work truck for relocation.
" It is lower stress for the beaver when you don't
have to handle them as much, " Altermatt said.
Despite the modifications to his trailer compared
to others, there remain some constants with this temporary beaver home such as feeding the beavers and
changing the water each day.
The beavers taught Altermatt some things about
the trailer, too. During a trapping effort along an irrigation canal near Byron in the fall of 2020, Altermatt
captured an adult nuisance beaver. He kept the trailer
at the site overnight and tried to catch more of the
colony, but the beaver chewed through the wire mesh
and got away. Altermatt replaced it with teeth-proof
chain-link mesh instead.
Altermatt said beavers do " fairly well " in trailers
between 10-14 days, which provides time to capture
other members of the family, although it's uncommon
to trap an entire beaver colony.
" Catching the first beaver is usually easy and often
happens the first night of trapping. Catching additional members of the family becomes increasingly
difficult because they get more and more trap shy, "
Altermatt said.

Jerry Altermatt checks a Comstock trap for beavers on a private ranch near Cody. (Photo by Chris Martin/WGFD)

Jerry Altermatt prepares to release a beaver from a Hancock trap into his custom-designed trailer until he can
relocate the beaver to a different area. (Photo by Chris Martin/WGFD)

The best times to trap and relocate beavers are
spring and fall. Midsummer is avoided because beavers raise kits at that time, and high temperatures
can stress beavers when captured. In the fall, beavers
also have to be relocated early enough to build their
dams and cache food for the winter. Altermatt also
curtails trapping in periods of extreme high and low
temperatures to avoid stressing the animals when
they are in traps.

Wyoming Wildlife | 35

March 2021

Table of Contents for the Digital Edition of March 2021