What you don’t know might not annoy you, but it might kill you. I include this section on rodents which you might encounter while elk hunting in the Rockies, but it is also pertinent to all US hunters who have a hunting cabin or hunt where there are derelict old barns and buildings. Rodent carried diseases can be avoided if you know the dangers and properly clean your hunt camp cabins. Critters will attempt to relocate from fields to human habitation with the advent of cold weather. That is abouit hunting season! This includes house mice, deer mice which can carry the deadly Hantavirus notorou virus, and pack rats which can mess up a camp and cart off possessions. We have been plagued with rodents in our Wyoming antelope hunting cabin. It took quite a while to understand their habits, the ways to discourage them , and how to efectively trap them. I might as well save you some time by passing on our experience. (Photos from Wikipedia) House mice: (Mus musculus) are mostly associated with human habitation. The mice vary in color, but are normally gray in non-laboratory breeding situations. They have a pointed snout, small round eyes and naked ears and tails. The tails are used for precise body temperature contol, so tails of southern mice (as shown) are longer than our northern mice. These mice communicate with high pitch squeaking. Both common mice and deer mice can wiggle through a 3/8 to 1/2 inch opening (depending on age and size) and enlarge holes with gnawing as they grow. Deer mice: (Mus peromyscus) are the most common mammal in the US, and have a range from Canada to Mexico. They are not not noticed much because they generally live scattered outdoors until cold weather arrives. There are seven varieties of deer mice and only mouse experts can distinguish the difference. The western US deer mouse Peromyscus manicalatus typically has a two-toned body, with a gold to mixed gold-gray top, white legs, and a distinct white belly and white tail bottom. The tail has short hair, again with the bottom white and a colored top appearing as a stripe. The snout is more stubby than the house mouse Deer mice usually remain mute, but communicate danger with coded foot thumping. They can jump three feet and are good climbers. They are omnivorous, eating plant and animal matter - insects, worms, seeds, nuts, flowers, fruit and even their own feces (coprophagy) if necessary. In the fall and winter they develop a craving for fat, to the extent they will resort to consume bars of soap – even scented soap! Deer mice move into buildings, sheds, and wood piles with the onset of winter. Favorite places to nest inside are beds and upholstered chairs where they can use stuffing for nests. They are excellent squirmers, the young being able to squeeze through a hole the size of a shirt button. Deer mice may have 5-11 kits 3-4 times a year; young reach puberty in a month. Over population can rapidly occur in warm years with good extended food supplies, delayed early frost kill, and reduced number of predators. Deer mice infected with hanta virus do not show any signs of sickness, being immune to the virus. Some colonies have up to 70% infected mice. Deer mice transmit the hanta virus via their blood, saliva and urine, especially if these liquids are dried and become airborne by natural drafts or human activities like vacuming, sweeping or shaking bedding etc. Eating contaminated food or drinking from cans whose tops have been contaminated by urine is another transmission source. The hanta virus is believed to be viable (contractable) on surfaces for seven to eight days. Packrats (Wood rats, Rafter rats:) There are 17 species of Neotoma, with expected variations in descriptions. They are large (adults one foot or more to tail tip) with hairy tails and somewhat small feet for their size. The bodies are typically paunchy and sort of floppy. Ears are dish-shaped and eyes black. Packrats build elaborate nests (often large) using any materials available. Rats in the wild may use cactus bases for protection, or caves, cliff crevices or even hollow stumps. These rats readily adapt to living around humans where they build nests in sheds, barns, garages and cellars. They love attics and walls if there are entrance opportunities: they are excellent chewers to enlarge holes. While packrats are cute and interesting animals, they can ransack a vacant cabin, neglected home or stored vehicle engine compartment. Packrats are the clowns of the rat family and many consider them as lovable like a hamster. They are nocturnal miscreants, continually messing around and foraging for nest building materials and food; some nests can become enormous with their kleptomaniac habits. They are noisy to boisterous, particularly at night. Their urine is particularly strong and obnoxious. They tend to urinate in the same place to the extent that artificial urine ”rock” can be created in caves over thousands of years. They are attracted to shiny objects and will often leave an item they are carrying for something they encounter that seems better to them, hence their name “trade rats”. (The pictured packrat was caught outside our house when a neighbor rat- proofed his shed, which was somewhat well nested for the upcoming winter.) Climate Historians: Packrats do not drink water, but extract moisture from their food to produce the viscous urine of highly distinctive odor. The urine dries to form crystalline amber-colored “amberat” that crusts the rat middens and can preserve coated vegetation for tens of thousands of years. Study of the packrat middens can reveal climate history back to the ice ages some 50,000 years ago. Climate study in western America is unique, because the rest of the world never had the rat historians. USGS Senior Scientist Julio Betancourt unlocked the utility of packrat urine deposits in the 1970’s. He has shown how vegetation responds to climatic changes by migrating if the changes are slow enough, or dying if there is insufficient transition time. High CountryNews, Marshall Swearington, Feb. 2016 Trapping Mice and Rats Poisons: I strongly recommend you do not use poisons. They enter the food chain when cats, dogs, birds and other animals eat the poisoned rodents. Warfarin-based poisons that make a rodents exit a building to find water are particulary damaging to the ecosystem. Poisons may be eaten by children. Mice and rats decaying in buildings is not sanitary, nor is the aroma appreciated. Deer mouse urine is a lingering danger because of the hanta virus. Bait: Use peanut butter worked well into the trap trigger. Let the peanut butter dry 2-3 days on a paper blotter which removes oil to make a thicker paste. This will prevent small mice and insects from licking away the gooey butter. Packrats like fruit in the fall and winter, especially a small chunk of aromatic apple. A better mouse trap can be devised by placing a vegetable twisty wire around the trap trigger (pull off the plastic – foil-wrapped vegetable twisties work easier). This makes the mouse work harder to get the bait and increases trapping success (see trap photo). Trap placement: Place traps in a protected place or box along walls outside and insides. The box prevents killing birds and squirrels, and reduces rebaiting if wind and rain trips traps, and trap avoidance training of your rodent prey. Mouse traps should be placed on newspaper or cardboard. This prevents soiling of floor with rodent feces, blood and hazardous urine if a deer mouse is trapped. (The hanta virus is transmitted in mouse urine which may be expelled with death and rigor mortis contractions.) Use plastic newspaper bags as gloves and handle the trap cautiously and slowly. Invert the plastic bag and throw out the trap with the deer mouse; do not use it again.) Packrats present a special problem because of their size and their ability to learn to avoid hazards a second time they encounter the hazard (good avoidance learners). You have to get a packrat the first time. I recommend placing a RAT size trap in an enclosure such as this box with an entrance hole cut in one end. This leads the rat to place its head over the trigger when it enters, where the trap spring will instantly kill it. Being curious animals, packrats may circle an open area trap and trigger it with their tail or foot. Wounding a packrat may allow it to escape to its nest, which is probably in the shed or house where you do not want it to rot and smell. For this reason, I also recommend a thin wire (not chewable string) attach the trap to a fixed or heavy object so that the rat does not drag away the trap. Note: if your outside mouse traps are missing, they may have been taken by a cat, fox, or a packrat building a nest. Another problem if you are in packrat country is that they steal mouse traps for their nest. We solved that problem at our cabin by screwing mouse traps to a wooden plank too big for the rat to carry off. We leave several of these planks on cardboard in our cabin when we leave for the winter, in case the mice somehow get in. It is much easier to remove the traps together in the spring. Wiring the bait to the trap trigger is essential. Packrats nimbly use their paws rather than their snouts to test bait. Once again, you do not want the animal to escape and die in your dwelling. Hunting Camps, Sheds, cabins and Barns: It is recommended people open all doors and windows and remain outside a while to let fresh air air into little used buildings to let air and to let dust circulate out. This will reduce the inhalation of dried deer mouse urine virus microcrystals wafted up by air currents. It also allows mice to calmly leave which is very important. Mice commonly urinate when panicked to run fast. (Hawks with UV light sensitive eyes can see mouse urine trails when hunting.) There are six common ways to contract the hanta virus. 1.) Breathing in airborne mouse urine or droppings crystals/dust/particles when cleaning a shed, barn, garage with a broom, vacuum cleaner, pitchfork or shovel which raises dust. Shed cleaning should not be done within 7-8 days (thought to be life viability span of the virus on surfaces) of the last mouse infestation. Cleaning should be with soapy Chorlox water to prevent dust from rising. 2.) Touching the mouth or nose aftter contact with mouse urine, saliva, feces, or blood (such as after handling traps or dead mice. Do not handle live deer mice, since a bite may transmit the virus to you. 3.) Eating food contaminated by urine, droppings or saliva of an infected mouse; dispose of all contaminated food. Wash food can tops and bottles if they were in a contaminated area or if they were in outside storage). 4.) Being bitten by an infected mouse. Never domesticate a wild mouse as a pet, even if it seems a cute thing! 5.) Pets bringing in a mouse that is then handled so there is contact with urine, blood, feces. 6.) Hikers and campers should be careful when seeking shelter in trails helters and old buildings, especially in low altitude areas where mice are not killed by winter cold. How prevalent is Hanta: The hanta virus is thought to be indigenous. It was not recognized until about twenty years ago when the deer mouse was discovered to be the host and and the virus was recognized as the cause for historic, new reports of sporadic occurrences of a strange “new” illness. Recognition of more cases in the US caused the US Center for Disease Control and Prevention to start monitoring cases. In the ten years of monitoring so far, there were 690 recognized and reported cases in 35 states, or about 6.9 per year of Hantavirus Pulmonary Syndrome (HPS)illnesses in Colorado. The fatality rate was 38%. The map below illustrates the range of recognized hanta cases and number of people contracting hanta during the last ten years. Cumulative (10 year) Case Count Per State Valid as of January 8, 2016 US Center for Disease Control and Prevention Hantavirus Pulmonary Syndrome (HPS) Cases, by State of Reporting Total Cases: N=690 in 35 States Not displayed: 2 cases reported with presumed exposure outside the USA Hanta virus symptoms: Early stage symptoms- fever, chills, muscle aches of large muscle groups like the hips, thighs, shoulders and abdomen; dizziness, fatigue, nausea, vomiting, diarrhea, general gut pains. Advanced stage symptoms – progressive shortening of breath, labored breathing, increasingly faster heart and breathing rate (signs of lungs filling with water = Hanta pulmonary edema, resulting in death without treatment.) There are no medical cures for the virus, so hospital life support methods are the only treatments. Closing note on hanta: You may think I over emphasize the hanta virus threat. The chances of contracting it are slim on a statistical basis. However, IF you get the virus the consequences are great. This was “brought home” to us when a friend of our ranch hosts died quickly after cleaning out a shed. A little caution and extra cleaning vigilance are worth preventing a death of a buddy, child or mate; guilt from negligence lasts a lifetime. Packrat Stories Lost and Found Pet: Steamboat Springs, Colorado, is quite a wealthy, elite town and almost anything can happen. A woman found a pet chinchilla and tried to return it to what must have been a grieving young person. No one answered her newspaper ads or postings. In December 2016, she accepted the pet as hers and took it to the veterinarian for a check up, since oddly it still had its short summer fur rather than a luxurious winter pelt. The TV news report was not detailed enough to describe how tactfully the vet was when he declared the valuable chinchilla to be only a lowly packrat. I can understand how the woman fell in love with the critter. They are playful, gentle, and inquisitive and adjust to people. The photo shows a packrat captured at our cabin by teasing it into a bucket with a piece of apple. I did not have the heart to murder the helpless Miss, so I carted it several miles away to old coal mine ruins and released her to find a mate. We need hearts, and we don’t need to kill everything. Careless Hunt Clients: An outfitter near the Flat Tops Wilderness had a license that permitted one raised wood platform for the mess tent. He related that his clients were down right inconsiderate when they took their after dinner and breakfast coffee outdoors. They would bring back their cups, but leave spoons where-ever to get lost. Soon there was a spoon shortage. One day the cook returned after saddling horses to find a something trying to pull a serving ladle through a knothole in the floor. That evening they pried up several boards and found about ten years of hoarded spoons in the rat nest – plus a trove of items that were thought to have been lost afield, or stolen by help or clients. I seems that packrat was enamoured to just spoons, having left forks and knives. What is in the Wall!!! After we refurbished (rebuilt) a settlers cabin we had a bad experience. We arrived for a planned Memorial Day week of relaxation at our remote retreat on a large Wyoming ranch. I did some additional repairs, and set out mouse poison under the woodpile. The weather became very warm. On the third day something arose, and it was not in a biblical story. An odd aroma began to percolate through the plywood, tarpaper and barn wood paneling near the head of my bed. On day five it became unbearable and on day six we were headed home. Evidently, a poisoned packrat had died in the wall and putrefied in the heat. Now you comprehend why I warn trappers to tie the ratt rap to a large object or stake, and not to use poison! .

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