Getting rid of voles

Asked July 28, 2018, 12:36 PM EDT

Hello, we live in the country adjacent to a field, and have always had field mice or voles in our yard. This year however they are crazy, running amok and creating holes all over the front and backyard. I am considering using zinc phosphide in the holes. Do you think that's a good idea? Thank you

Benton County Oregon vertebrate pest management horticulture

2 Responses

Hi and thanks for contacting Ask an Expert.
It certainly is the year for moles, voles, mice, ground squirrels, etc. Since you asked for an opinion, I will say no, I do not think it is a good idea. This chemical produces phosphine gas which can damage all mammals if inhaled or eaten. The chemical is activated by a low pH or stomach acid and water when the animal eats it and can cause cardiac edema and kidney failure, thus killing the mammal however, another animal that decides to eat it may also die or become extremely ill. While most predators (foxes, cats, owls, hawks, etc.) of these rodents do not eat the digestive tract (where the chemical is activated) they may puncture it and breathe in the chemical. It is also injurious to fish and can move through the soil to water.
Aside from that if you have pets that roam free; they may become ill or die.
This chemical comes in a powders and pellet form. It is particularly poisonous to waterfowl and if you are going to use it, wear gloves when placing it as it is poisonous to humans as well, causing nausea, possible kidney damage or edema.
I suggest using mouse traps with peanut butter. These work extremely well, from my own experience. I caught 11 mice in 11 days by re-setting one trap every evening and placing it out after dark. Voles would also be attracted to peanut butter too.
Cats are also advantageous if left out at night and of course there are mole/vole/gopher traps that can be purchased. Some that go right in the tunnel with prongs or shoot an arrow-like prong when jarred. If you keep the grass short, it discourages voles as they like the cover of brush to roam around.
Poisons have a way of getting into the environment and damaging unintended victims. As I said earlier be very careful not to get this poison on you, your skin or inhale it and keep your pets out of the area for extended periods. Pelleted poisons will be eaten by birds and since they are so small, cause death.

A quick PS to Sheryl's thoughtful response, with a few other helpful resources:

To more effectively trap voles using snap traps, you can drill holes in wooden mouse traps and use nails stuck through the holes to secure traps right at the entry to burrows.

If you opt to do your own pest control, the National Pesticide Information Center is a very useful resource to help evaluate the pros and cons of the many products and techniques available. Look for methods that limit risk to non-target wildlife and pets which might feed on poisoned rodents.

If you hire a professional to deal with your rodent situation, check out Choosing a Pest Control Company: IPM Is the Key.

If you have the right location, part of your solution could be attracting raptors like kestrels and owls. Attracting Birds of Prey for Rodent Control has more details. Many birds of prey can actually see UV light emitted by vole urine and are attracted to vole runs.