It’s fall. What to do about mice?
Not so cute when they’re on the counters.
Image: flickr / Chris Isherwood. Licensed under CC BY-SA 2.0
You’ve likely seen the small black boxes labeled “Do Not Touch – Poison” lurking outside a business or restaurant. Perhaps you’ve even used rodenticides -- rodent poisons -- around your home. No one wants mice in their space, but these poisons carry a heavy price for our natural world. So what’s a thinking person to do? Understanding the alternatives is important for each of us that cares about Coal Creek and our local wildlife.
What’s an anticoagulant rodenticide?
Some mouse/rat poisons contain anticoagulants, meaning the poison works by thinning the blood and causing the victim to bleed to death. The poisoned rodents are weakened and become easy prey for animals up the food chain, such as raptors, coyotes and bobcats.
How do rodenticides hurt wildlife?
The toxic food web, or how rodent poisons end up in coyotes.
Used with permission from Raptors are the Solution.
These same blood thinners accumulate in the blood of predators, and the statistics on predators impacted by anticoagulants in their blood is sobering. The National Park Service reports the following statistics from a 2019 study in the Santa Monica Mountains:
Bobcats: 92% of bobcats exposed to anticoagulant poisons
Coyotes: 83% of coyotes exposed to anticoagulants, which are their 2nd leading cause of death
Tufts Wildlife Clinic reported that 100% of the 43 red-tailed hawks admitted over a two-year period tested positive for anticoagulant rodenticide.
There’s also a link between rodenticides and mange in the coyote population. By eating rodents poisoned with anticoagulants, a coyote’s immune system becomes weakened, making them more susceptible to the parasite that causes mange. These sickened coyotes, which often succumb to slow and painful deaths, have been shown to roam more during daytime hours than would be typical for a coyote, resulting in increased conflict with domestic animals and people.
What are my best options to control rodents?
Prevention is always number one. According to the National Park Service, the following advice can help you manage rodents without anticoagulant rodenticide poisons:
Before you have a rodent problem: Remove food resources and hiding places.
If you have rodents: Use snap and/or electric traps to remove rodents. Remember also that you need to remove food resources and hiding places to prevent rodents from returning.
Reduce food sources for rodents
Remove or prevent rodent access to fruit and nut trees. Trim trees away from fences, roofs, and telephone lines; attach tree guards on tree trunks
Prevent access to vegetable gardens. Cover or enclose with net or wire
Clean up and seal up domestic animal food.
Remove bird feeders.
Clean up and seal up trash.
Seal up compost piles.
Clean BBQ after using.
Reduce hiding places and shelter for rodents
Seal up holes and cracks into house, attic, crawl space, garage, sheds, etc.
Clean up wood/brush/junk piles that provide shelter to rodents
Remove thick vegetation where rats can nest
Remove tree limbs within three feet from roof
If your rodent problem is too big for you to control, contact a pest-exclusion company that uses sustainable practices that don’t involve poisons. Pest control companies that practice Integrated Pest Management should be able to help you get to the root of the problem, i.e., seal up holes and trap rodents without the use of poisons. If you go this route, be sure to ask lots of questions to better understand the approach and the potential impact on wildlife.
Check out this webpage for more information from the National Park Service.
There are also a variety of natural options available, such as:
Spray or sprinkle areas of concern with peppermint, cinnamon, cayenne pepper, or citronella oils, or spray red wine vinegar on hardscapes (avoid plants).
Use humane catch and release mouse traps with peanut butter bait. It’s not legal to relocate rodents in Colorado, so only move the rodent outside your home. Note, however, that mice and rodents that have lived indoors have a low chance of surviving outdoors. The Humane Society of the United States recommends relocating mice to an outbuilding such as a shed or garage, if possible.
Use a natural pest repellent such as Nature’s Mace.
Apply peppermint oil on cotton balls and place them inside a vehicle if rodents are either getting in the vehicle or chewing on wires.
For voles, spread coffee grounds on the lawn, under bushes, and along fence lines.
Spray the thresholds of doors and windows with peppermint oil to keep out unwanted pests.
Will you help our wildlife?
Mice like to live near humans, but wildlife can be our ally. Let them work by avoiding the use of anticoagulant rodenticides and using the ecologically friendly strategies in this article to control unwanted rodents. You might even get to see an owl.