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Weasels
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Andy's Tracks & Trails
Weasels / Ermine

Short Tailed Weasel-Ermine in winter coat.
My first encounter with a weasel occurred at the age of 10 or 11.  While I don’t remember exactly how old I was, I do remember the event like yesterday.

On my way to check some muskrat traps at a frozen pond in my area, I was crossing a weedy field with a large log/brush pile in the back.  About an inch or two of fresh snow the night before had everything covered in a clean white blanket.  As I approached the brush pile, I noticed small tracks leading in and out of the branches, logs and junk the land owner had discarded over the years.  Curiosity got the best of me and I had to figure it out.  What made the tracks?  

The tracks were very small, a two by two bounding pattern, spread more than a foot apart from the previous track.  Tracks showed where the unknown animal had investigated every hole and hollow log, had gone under every old board and into anything it could crawl into.  While following the tracks I began to stand on some of the branches to get a better view when movement caught my eye.  A dark nose, two beady black eyes and a black tipped tail betrayed the otherwise pure white fur covering the critter responsible for all the tracks.  A weasel, or ermine if you will, stood boldly only three feet away from me, and watching my every move!  It did not appear to be frightened, and hissed at me before diving under the snow as I moved closer.  For the next several minutes the weasel played hide and seek with me, disappearing in a flash when I neared, only to reappear seconds later a few feet away.  I was captivated by its quick movements, boldness, and beauty, and I wanted to catch one!
Male (top) and Female (bottom) Short Tailed Weasels

Since that first encounter years ago, I have trapped many weasels on my traplines, and observed many more while being outdoors.  I haven’t lost the feeling of excitement when I see one, and am always happy each year to add a few to my trapline harvest.

What kind of Weasels are found in Minnesota?
The most common is the Short-Tailed Weasel, called Ermine, when white.  Present in most all Counties of the State, Short Tailed Weasels vary from 7 to 15 inches in length, weighing between 2 and 5 ounces.  Males are larger than females.  The summer coat is tan with white or pale brown underneath and the tail is black tipped.  As days get shorter in the fall, the pelt begins to molt and turn white.  It is said that Short Tailed Weasels have a tail roughly 1/3 the length of their total body.  Short Tails can mate anywhere from late summer to mid-winter.  Like other members of the Weasel family, Short Tails experience “Delayed Implantation” which means that the embryo does not develop right away after mating.  Once the embryo starts to develop, young weasels will be born a month later.  Under ideal conditions, an adult can raise two litters per year.

Long Tailed Weasels are the second most common weasel found in Minnesota.  Although they range throughout the State, numbers may vary significantly and they are usually less abundant.  Adult males may be 15 – 20 inches in length including its tail and weigh 7 ounces.  Female long tails will be somewhat smaller.  It is said that the tail of a Long Tail Weasel will be 40% or more of its body length.  Summer coats are similar to Short Tailed Weasels, dark brown or tan with light brown or white belly.  The tail is also black tipped. Track pattern resembles a female mink, but slightly smaller.  
District 6 Trapper Fran Satnik with a Long-Tailed Weasel in 220 body grip from a Bobcat set.
The Least Weasel is our smallest, averaging between 6 – 7.5 inches in length, including tail.  The tail is much shorter than the other two weasel types, usually no more than 25% of total body length, and is not black tipped.  Summer pelts are similar to the other two weasels in coloration.  An unusual fact about the pelt of the Least Weasel is that its white pelt fluoresces under ultraviolet lighting, while the other two weasel species do not.  Records show the Least Weasel was more often found in the north and west portions of the State, but is now uncommon, and has been listed as a “Species of Concern” by the MN DNR.  I have never seen or trapped one.

What do they eat?  
Weasels are extremely active animals.  Always on the go.  Because of this, they are always hungry and looking for food.  While capable of taking animals larger than themselves such as rabbits, chipmunks and small birds, most weasels are looking for smaller animals, mainly mice and voles.  Think of them as the world champion mouse hunters.  Weasels are known as surplus killers.  When food is easily available, they will kill far more than they can possibly eat.  When a weasel gets into a pen with young chicks or ducklings, a single animal may kill dozens, and eat only a part of one.

Great weasel habitat.  Brush and grass at edge of marsh.
So, where do I find easel sign?
Short Tailed Weasels can be found in a variety of habitats.  First, look for areas with a good population of mice and voles.  Look for the small two by two bounding weasel tracks on the ice in cattail marshes.  Smaller than mink tracks, they often travel from muskrat hut to muskrat hut.  Also, along the marsh edges hunting in and out of the long grass found there.  Most brush piles will show sign of weasels hunting.  Any creek or stream bank that is weedy or has long grass will show tracks, often traveling on the ice.

Bush country, with bogs and willow brush will hold good numbers of weasels.  Check blown down trees, old stumps, trash piles, beaver dams, and abandoned beaver lodges for weasel hunting areas.  In the northern forests, look for thick cover and tall grass.  Areas that have been logged a few years earlier will show good populations of weasels when the willows/poplar start growing back.  Blow downs from storm hit areas will see good weasel populations.  They are very capable of climbing trees and leaning logs.  

In farming and open country, drainage ditches with grass and weeds will show weasels hunting there.  I seem to find Long Tailed Weasels in the more open country.  Set aside fields, weedy fence lines in open fields, Juniper bushes on hillsides with tall grass beneath them, small groves of trees around abandoned buildings, and County ditches with weeds and water.  Look for anything that narrows the weasel’s movements – pinch points, to make sure they travel close to your set.
Fresh weasel tracks along field road and tall grass.

What equipment do I need to trap Weasels?
For those just starting out weasel trapping, two pieces of equipment are most important – a wooden bait box, also called a weasel box, and a snap type rat trap.

Weasel boxes can be a variety of shapes, but generally look like an elongated wooden bird house, with sliding or removable top.  The front will have a hole from 1 ¾ - 2” diameter, situated towards the top of the front panel.  The back panel will be either screened, or with a 2” screened in hole, to allow better scent circulation.  The general outside dimensions are 13” long by 6” wide.  Boxes may have a 2 – 3” front overhang, to keep the opening from being plugged with snow.  A hinged or sliding top, or top with duplex nail fitting into a pre drilled nail hole, will secure the top from larger predators yet allow the trapper to open and rebait or remove a caught weasel.  The general purpose is to have a container for trap, bait, and to protect the weasel once caught, from scavengers.  All these boxes are easily made by the trapper, or purchase a weasel box from numerous trapper’s supply dealers.  If you like making things, building plans are available off the Internet.
Interior of Weasel Box, with bait location, trap placement, and weasel catch.  Catch by District 6 Trapper, Andy Schmidt.

Traps are usually the snap type rat trap, situated on a wooden base, with swing arm striker bar.  Those with the larger plastic pan seem to work best.  Several brands of plastic base rat traps work well too.  The wooden rat trap fits inside the box, just inside the front panel entrance hole, with bloody bait placed in the rear of the weasel box.  Upon entering, the Weasel will usually step down onto the pan and get hit by the striker bar, quickly dispatching it.  Other options include a variety of foot hold traps, including the #0, #1 and 1 ½ long spring traps, and the smaller #1 jump or coil spring traps.  These traps will usually catch a weasel across the body, quickly dispatching it.  
Number one long spring trap inside weasel box.  Perfect catch, quick dispatch.  Muskrat for bait.  Caught by District 6 Trapper, Andy Schmidt.
A word of caution here, if using the foot hold traps, attach wire or cable to the end of the trap chain and run it outside the Weasel box, anchoring it to a solid object.  Raccoons, Mink, Skunks, Opossums, and other larger furbearers can easily reach into the entrance hole and potentially get caught in the foot trap.  Without being anchored properly, a long tracking and search may be necessary to recover your weasel box and trap!    

What about bait and lure?
Many different types of bait can be used for weasel trapping.  Rule of thumb – fresh, and bloody will work best.  Beaver, muskrat, rabbit, and venison scraps have all worked well for me.  So has duck livers saved from waterfowl hunting.  One of the problems with bait, especially at very cold temperatures, is that it’s scent will carry less distance.  I have found that the extra oil in beaver fleshing retains scent far longer than lean meat during extreme cold.  I save all my beaver fleshing for bait purposes for a variety of furbearers.  Beaver fleshing mixed with muskrat, or fresh beaver meat works great.
Mid-winter Striped Skunk caught in foot trap placed inside weasel box set.  Trap was wired to nearby tree, securing it, and keeping the skunk from escaping with the trap.

In regards to lure, mild weather sets can be improved with Weasel Lure.  Many weasel lures are made with Anise Extract, which weasels are attracted to.  In extreme cold weather I will use a louder call lure a foot or two away from the set.  Once close, they will smell the bait.  Salt can be mixed with the bait to help prevent freezing.  I will use table salt mixed in with the bait container contents.  Seems to work well.

Bloody baits can stain the white fur of a caught weasel.  One way to help prevent this is by placing bait into a container inside the weasel box.  Plastic frosting containers from store bought cinnamon rolls or metal cat food containers help keep the bait in one spot, and the box easier to clean once the set is pulled.

A rusty striker bar on a rat trap can also stain a prime Weasel pelt.  Wrap the striker bar in electrical tape, or duct tape, and your weasel will not get a rust stained pelt.  
District 6 Trappers, Gavin and Morgan Herschman, with new weasel boxes they just built, ready for setting!
How can a stained pelt be cleaned up?      
After catching a weasel, I will check the entire pelt for blood or urine stains.  After removing it from the trap, I will gently rub it in clean snow near my catch site, to free up any blood that may be on the pelt.  At home I will use cold water to rinse away any blood stains.  The whole weasel will then be placed into a tub of Borax and I will repeatedly brush the fur, using an old toothbrush, to loosen any remaining dirt or blood.  The Borax powder will also dry the fur by absorbing the water left in it.  This works very well on blood stains.  While it can help with urine stains, it may not entirely remove them.  Upon completing its Borax bath, the cleaned weasel is placed into a small zip lock bag and put into the freezer until ready to skin and stretch at a later date.
Problems and Tips
This one’s occupied!
Mice and Shrews will clean out the bait in a weasel box rather quickly.  As a rule, I plan to rebait at least every week. Remember, fresh bait works best.  Warm weather gets new bait multiple times a week.

I have sometimes been frustrated with snapped traps, but no catch.  I believe this may occur when a weasel enters the box and sees a mouse or shrew.  Rather than stepping down on the pan, a chase ensues inside your weasel box, firing the trap with no catch.  Not much you can do here.  Foot traps will often require a little more pressure to move the pan down, so if you’re convinced mice and shrews are firing the rat trap, try a foot hold.  

When placing weasel boxes on ice, or in freezing/thawing conditions, make sure you put some sticks or dry grass underneath the box so it can be easily removed when pulling the set.  I hate chipping ice in a culvert just to free a set.

I have trapped many weasels in locations prior to seeing tracks in the snow.  Also, some snow conditions do not allow a weasel to leave a visible track!  After a while, you just recognize good habitat.  Given my choice, I prefer to set out boxes in areas with fresh weasel tracks.  Catches come quicker!
Tanned furs, including weasel pelts, just back from the Tannery.
Boxes, once built, will last much longer if painted or stained.  Both inside and out.  Also helps prevent blood from being absorbed into the wood and later giving off a foul odor.  

If possible, I will face my box opening to the south or west.  On sunny days, the box will absorb heat, melting snow which may block the entrance, and warm the bait, giving off more scent.

When building weasel boxes, put the entrance hole up towards the top of the front panel. When a weasel enters, it is dropping with more force, making it more likely to trip the trap pan.

My weasel boxes are often placed on my trails to fisher and bobcat sets.  Winter weasel traplines are also great opportunities to scout for fisher, marten or bobcat sign, and locate travel ways and funnels for the larger predators.  Work on winter track identification and reading animal sign, watch how weather changes affect animal movement, experiment with new bait and lures.

If you’re looking to extend your trapping season in mid-winter, or you’d like to introduce someone new to trapping, consider a weasel trapline!     



©️ Copyright 2020 MN Trappers Assn. All rights reserved.
©️ Copyright 2019 MN Trappers Assn. All rights reserved.
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