We are hearing many sounds of the season right now, some welcome – like the chip notes of yellow-rumped warblers during fall migration and the crunching of dead leaves underfoot – and some not so much, like the scratching of mice that have moved into your walls. With the decreasing temperatures, we receive an increasing number of inquiries about dealing with mice and other rodents that find our homes more appealing than the outdoors. While some situations will need professional help, I wanted to provide a naturalist’s opinion on coping with wildlife in your home in the fall and winter.

It helps to start with the basic acknowledgement that your home, for all the reasons it is ideal for you, is just as ideal for the wildlife that may want to share it with you: It is warm, insulated, and a great place to store food and to sleep.

Without stating the obvious, the best way to keep wildlife out is to not let it in in the first place. Now is a great time to check the exterior of your house for openings, gaps or holes where animals could get in and do your best to seal them up. Caulking small holes and gaps is a good start. Look for larger holes that may need to be filled or covered with hardware cloth. Check in corners, around pipes and especially near fireplaces. I was amazed to find a sizable 2-by-2-inch gap between our chimney and the exterior wall, which might as well have had a “Welcome to Maine” sign next to it with how much traffic it probably got before I sealed it up.

If wildlife is making it inside your house, we strongly recommend you attempt nonlethal methods of removing it first. There are several types and sizes of live animal traps, often known by the now-genericized name Havahart, that are specific to your location and problem animal. It is worth putting in the effort to make sure you are well prepared – get a proper-sized trap, find an attractive bait and make sure you are setting it properly – before starting the endeavor. You don’t want to end up like Tom, with your hand in a mousetrap, while Jerry snickers on the other side of the wall.

Once the animal is trapped, we recommend relocating it back outside but not moving it too far. For the survival of that animal, it is important to keep it within its home range. If you’ve already taken the first step of sealing up the holes and gaps in your home, then there shouldn’t be any problem releasing the animal (or animals) back outside. If they are still getting in, that means you have more searching to do. We strongly discourage the translocation of animals – the capturing and moving them long distances and far from the established territories. Being moved to a new area where they will have to compete with other established animals, potentially new predators and no knowledge of where resources are located typically results in very low survival rates.

Sometimes you will find scenarios where lethal control methods are required. We think it is important that you always begin with addressing the problems, as outlined above, before turning to lethal alternatives, because as long as you are providing a warm home, it will be used. Your house likely has some carrying capacity (some population it can sustain), and as soon as you remove one individual, you are just making room for the next. So start by doing your best at making that capacity is zero.

If you have to use lethal methods, consider those that will be effective and minimize secondary harms. We recommend snap-traps as a more-humane method, but again, make sure you are setting them properly to be most effective. We do not recommend you use pesticides as they are inhumane (most cause brain swelling or are anticoagulants and cause internal bleeding), can lead to secondary poisoning (like an owl catching that poisoned mouse), or the animal can die away from the source site (and now you have a smelly dead rat in your wall).

It is always hard to give blanket recommendations as everyone’s situation will vary, but these should cover the basics. Take advantage of these warm days to patch up holes and get ahead of any problems you might have.

Have you got a nature question of your own? Email questions to ask@maineaudubon.org and visit maineaudubon.org to learn more about birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug and other naturalists lead free bird walks on Thursday mornings, 7 to 9 a.m., at the Gilsland Farm Audubon Sanctuary in Falmouth.

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