Voles are a rodent species capable of causing a lot of damage because of the their ability to multiply quickly in response to abundant food. Cultivated crops, orchards, and lawns in Utah often feel the burnt of this damage. The damage may be particularly severe in areas experiencing drought conditions.
Population levels generally peak every 2 to 5 years, but these cycles are not predictable. These populations shifts may result in densities ranging from a few to several hundred voles per acre. In rare cases, vole populations may become extremely dense. During the early 1900s, vole populations were estimated at 25,000 per acre in some areas of Nevada.
As I mentioned, voles can cause severe damage to orchards, ornamentals, and tree plantings by girdling seedlings and mature trees, especially when populations are high. Studies in New York have demonstrated that girdling by voles can reduce fruit yield in apple orchards by as much as 66%.
Girdling of woody plants primarily occurs during fall and winter. Field crops, lawns, and golf courses also may be damaged by vole’s extensive runway and tunnel systems.
Fortunately, voles pose no major public health problems because of infrequent contact with humans.
However, they can harbor disease organisms, such as plague and tularemia. For this reason, voles should never be handled. If you have to handle a vole, or any other species of wildlife, you should wear the appropriate protective clothing (e.g., leather gloves).
Girdling damage and gnaw marks caused by voles are similar to that of many other species of wildlife, particularly rabbits. This, coupled with vole’s small size and inconspicuous nature, often leads individuals to believe vole damage is caused by other wildlife species. Vole girdling is characterized by non-uniform gnaw marks which occur at various angles and in irregular patches. In contrast, rabbits clip branches with neat, clean cuts.
Additionally, gnaw marks left by voles characteristically are about 1/8 inch in width and 3/8 inch in length; gnaw marks caused by rabbits usually are larger than this.
Careful examination of girdling damage may be needed to identify the animal that caused damage.
However, perhaps the most prominent sign of vole damage is the presence of their extensive runway system. Runways are 1 to 2 inches in width and vegetation is often clipped close to the ground next to well-traveled routes.
Control usually falls into 3 categories - habitat modification, exclusion, and population reduction. To ensure long-term control all three measures should be implemented simultaneously.
The elimination of weeds, ground cover, and litter around lawns and ornamental plantings can reduce habitat suitability for voles and lead to a decreased likelihood of vole damage. For example, lawns should be mowed regularly and mulch should be cleared 3 feet or more from the base of trees. Additionally, soil cultivation destroys vole runway-systems and may kill voles outright. For these reasons, plots of annual plants often are less susceptible to vole damage than perennial plants.
Cylinders made of hardware cloth (available at most hardware stores) are often effective in excluding voles and protecting individual plants. The mesh size of the hardware cloth used to construct cylinders should be no larger than 1/4 inch in size. The cylinder should be buried at least 6 inches below the ground surface to ensure that voles will not burrow under the hardware cloth and gain access to the plant. Although this technique will protect individual plants, fencing typically is not effective in
3 protecting large areas (e.g., lawns) and probably is cost prohibitive.
There are two chemicals approved for use in By EPA for repelling voles. These two repellents may contain thiram (afungicide) or capsaicin (chemical that makes peppers "hot") and act by altering the taste of plants and making them unpalatable to voles. Although these repellents may provide temporary protection for plants, their effectiveness usually is short-lived. Voles may become accustomed to such repellents and forage on plants even after treatment.
For a more long-term prevention effort, other techniques should be considered.
The EPA also currently approves of two toxicants which may be used to lethally control vole populations. The toxicants are zinc phosphide and anticoagulants. Of these, zinc phosphide is more commonly used. Zinc phosphide
(2%) is available in pelleted and grain bait formulations and typically is broadcast at rates of 6 to 10 pounds per acre. Additionally, zinc phosphide baits may be placed by hand in runways and burrow openings. Occasionally, it may be necessary to prebait (placement of nontreated bait prior to applying toxic baits) an area where voles hive become shy of toxic baits. Although zinc phosphide baits can be highly effective in reducing vole populations, you should be aware that this chemical is also toxic to groundfeeding birds, particularly waterfowl. Hand-placing baits in burrows and runways greatly reduces the risk of birds feeding on zinc phosphide baits. Zinc phosphide is also toxic to humans when ingested and may be absorbed through the skin. For these reasons, you should always wear gloves when handling zinc phosphide baits and dispose of the gloves in a safe manner. Additionally, zinc phosphide baits should be kept away from small children.
Zinc phosphide is considered a restricted-use chemical. As such, to use zinc phosphide baits you must be a certified applicator. If you are interested in becoming a certified applicator, contact your local county extension office.
Anticoagulant baits are also an effective means of reducing vole populations. Anticoagulants often are used to reduce rodent populations in general; approximately 95% of mouse and rat control is performed with anticoagulants.
As with zinc phosphide baits, anticoagulants can be broadcast over an area or placed by hand in runways and burrows. Additionally, anticoagulant baits are often glued to the inside of a water repellent paper tube to make an effective, disposable bait container. Anticoagulants work much slower than zinc phosphide and death is delayed for several days following the ingestion of a lethal dose. This slow action offers an important safety advantage where pets or livestock frequent because it provides time to administer the antidote (Vitamin K1) to an affected animal.
Like zinc phosphide baits, anticoagulants can also be toxic to humans. Therefore, you should take precautions to prevent children from gaining access to anticoagulant baits.
For more information about these toxicants, their use, and how to obtain them, contact your local extension office.
THINGS NOT TO DO
Frightening devices have been shown to be ineffective in reducing vole damage.
Fumigants usually are not effective in controlling voles because the complexityand depth of vole runways and burrows allow the fumigant to escape before voles are exposed to it.
Trapping may be effective in controlling very small vole populations, but, because of vole’s high reproductive rate, the time and labor costs required to eliminate voles are probably prohibitive.
In the event that voles invade your house (which is a rare event), individuals can be removed with snap traps or live traps as you would for house mice. Shooting generally is not regarded as a desirable method of vole population control.
Posted on 1 Aug 2007
Professor & Wildlife Resource Specialist
It's actually very difficult to tell a girl from a boy ladybug. One good way is to get a hand lens and look at the end of the abdomen (or where you think the "butt" might be). If it's rounded, it's probably a girl. If it's pointed, it's probably a boy. There are other general characteristics too, but they would be too complicated to explain over email and maybe too confusing for a 6-year old. The only real way to know for sure is to dissect it and look for reproductive organs (e.g., ovaries/testes).
Posted on 10 Jan 2008
Although squirrels could be the source of your bulb damage, some other culprits may include skunks, raccoons, voles, rabbits, ground squirrels, and birds. The best way to determine the source of the damage is to locate for evidence such as tracks and gnawing or tooth marks on any bulbs that remain.
Squirrels, and the other species listed may entirely remove the bulbs from the area and eat them in another place. However, they may also eat as much as they can at the scene, thus leave evidence of gnawing. If a skuck is your problem, you should be able to catch a hint of their odor.
Voles and rabbits will eat the bulbs at the scene. Additionally, gnaw marks left by voles characteristically are about 1/8 inch in width and 3/8 inch in length; gnaw marks caused by rabbits usually are larger than this.
What to do? Exclusion is probably best.
Protect newly planted bulbs with1-inch mesh poultry wire. Dig a trench slightly deeper than the desired depth of planting and fit the poultry wire inthe bottom. Add dirt and plant the bulbs. Place another strip of poultrywire over the plantings so that thebulbs are completely encased, andfinish covering with dirt.
In the case of a raccoon, rabbits or skunks, they can be live-trapped an removed form the area. This technique does not work well for squirrel however. Research has demonstrated the relocated squirrels quickly find their way back home.
What not to do?
Although there are a number of commercially available repellents on the market, given climatic condition and regular lawn and garden watering schedule they will probably not be effective for you. Also, their are no toxicants registered for use against squirrels, raccoons, skunks, and rabbits. If you suspect ground squirrels of voles, we do have some options.
Posted on 1 Aug 2007
Professor & Wildlife Resource Specialist
We own a cabin in Oakley, Utah, and had a skunk underneath in July of last year. The odor has lingered but
we think the skunk may have died or just left because the smell is going away. We want to prevent more from going underneath again. Is there a barrier type wire mesh that we can have installed or do it ourselves
As one who has done quite a bit of research on skunks, handled dozens of them, and even been sprayed more than once, I can appreciate you dilemma.
The largest and most common skunk in Utah is the striped skunk (Mephitis mephitis).Besides being infamous for spraying when threatened, skunks cause other types of damage. They will raid poultry houses for eggs and dig up lawns, golf courses, and other sodded areas searching for white grubs and earthworms.
Because skunks are the major wildlife vector for rabies, please be careful. This disease is endemic in the skunk population throughout Utah. The incubation period of rabies in infected animals is highly variable but can be extremely long. The length of infected animals is actually transmissible is also variable, ranging from three days to two weeks before the onset of symptoms. Once symptoms appear the disease will normally kill the infected animal within a few days.
Diseased animals may display abnormal behavior such as staggering, blundering walk, aggression toward people or other animals or daylight activity. Skunks displaying such abnormal behavior may be rabid and should be avoided or destroyed.
The best control around buildings is prevention. Do not allow skunks to establish themselves in or under buildings. All holes in foundations or other points of possible entry should be sealed using sheet metal, cement, hardware cloth, chicken wire or bricks. If you use sheet metal or hard ware cloth. Be sure to bury the bottom six inches of the material under the ground to prevent them for digging under it.
If a skunk has already become established under a building, all openings but one should be sealed. Sprinkle a 2-foot square patch of flour in front of the one remaining opening. Check the flour patch two to three hours after dark for tracks. If the tracks show that the skunk has left, seal the openings at once. When the skunk returns and finds that he cannot get back in, he will leave the area. This method should not be used in April, May, or June as there is a chance that young animals may be present and would be sealed in.
Now the about the lingering odor. Skunk odor is one of the most persistent and offensive odors in nature. The odor provides the skunk with it best line of defense. Diluted solution of vinegar or tomato juice can be used to remove most of the odor from pets, people, and clothing. Clothing can also be soaked in weak solutions of ammonia. If the mishap occurs while camping, clothing can be smoked over a juniper fires.
Walls, rooms, or other areas that have been spayed by a skunk can be treated with nuetroleum alpha. If the chemical is not available through local cleaning supplies stores, check on-line. Also, many cleaning stores now have products that can also remove the odor. If you can't find any nuetroluem alpha, let me know. I have some demonstration product I can give you.
Lastly, if you happen to encounter a skunk when enclosing the patio and get sprayed in your eyes, you will most likely experience a burning sensation and some temporary blindness. Your recovery time can be hastened by rinse your eyes with cold water.
Posted on 1 Aug 2007
Professor & Wildlife Resource Specialist
You can bring your spider specimen into the county Extension office and the Agent will be able to tell you if it is likely to be one of the three poisonous spiders that we have in Utah. He may need to forward the specimen to the University for verification if that is important to you. The verification cost is $5 per specimen.
The Extension Agent may be able to identify other spiders, however there are numerous species and he will not be able to identify all of them. Other sources of spider identification are entomology experts at your local colleges and the internet. Health Departments can often identify the poisonous species .
Posted on 10 Oct 2007
Agriculture Agent, Weber County