While we might see this as destructive, it is hard to blame them – it’s exactly what they would be doing with any natural cavity as well. However, if we look at a red squirrel, only a couple of inches larger than a chipmunk, we find a mammal that I think of as being more likely to expand an opening on a birdhouse. Eastern chipmunks typically prefer using underground burrows for most of their nesting and food storage. Mice are small enough that they can usually enter a cavity with ease, which eliminates them as suspects from Stephen’s mystery.Īs we go up in size on the mammal scale, we start to encounter other likely candidates. Some will even gather insulating materials for bedding. In order to stay active, these mice need to have lots of food available to them and will often take over cavities, especially birdhouses, as a place to cache their food. Then we have our deer mouse and white-footed mouse, which will stay active in the winter. They’ll go into a state of significantly lowered metabolism, including lowering the heart rate, body temperature, and respiratory rate. Maine’s two species of jumping mice are true hibernators. We have several species of mice in Maine, and different species use different techniques for making it through the winter. Let’s look at those and see if they may be the culprits behind this behavior. A fairly diverse group of birds will use cavities, but other animals, particularly mammals, are very fond of cavities and all the protections they provide. Primary cavity nesters excavate their own holes for nesting but will only use it for one season, and then leave it to be used by secondary cavity nesters. These can be formed when limbs break off trees, or can be created by primary cavity nesters, like woodpeckers. What is going on?” In the photo he provided, it looks like someone or thing has been chiseling away at the wood an inch or two all around the circular opening.īirdhouses are just a replacement for a natural cavity that occurs in the landscape.
A new question came in this week from Stephen Forrest of Brunswick: “Something has been chipping away at the entrance to my bluebird nesting box, almost as if (it) is trying to widen the opening.
We get a lot of questions about birdhouses in March as we head into the nesting season and people wonder about any maintenance or things they should do ahead of the coming spring.