Bird Watcher's General Store

“A Cape Cod Destination Icon For 40 Years”

When To Clean Your Birdhouse

Dear Bird Folks,

Back in late February, when we had that record-setting warm spell, I saw birds checking out one of my birdhouses. I’m pretty sure I didn’t clean out that particular box last fall. Is it too late to do it now?

– Leon, Avon, MA


Come on, Leon,

You’ve had six months to clean out one little birdhouse and now you’re telling me you haven’t been able to work it into your schedule. What have you been doing all this time, waiting in the wrong line at the DMV? (I’m just teasing you; every line at the DMV is the wrong line.) I shouldn’t be the one to talk about putting things off. Some of our holiday decorations are still up. My wife keeps insisting it’s time to take down the Christmas tree, but as long as there are a few needles left on the branches, I say it stays up. (She can be a little wasteful sometimes.)

No, it is not too late to clean out your birdhouse, but time is running out. I clean my houses the minute the nestlings have fledged, even if it’s in the middle of the summer. That way the box will be ready in case the bird couple decides to have a second brood. A word of caution: When cleaning a box in the summer, you have to be certain birds aren’t still using it. If you aren’t sure, it’s best to wait until fall (late September). In addition, I suggest that you also give your boxes another quick check in early spring (which is now). Why now, too? Occasionally, I’ll find that some creature has filled a box with acorns, or a mouse has turned one of my birdhouses into its winter home. (This is when I trick my wife into cleaning it out.)

When it comes to cleaning out nest boxes, there are a few things to keep in mind. First of all, never blindly reach into any box. One year I climbed up a ladder, removed the cover of a nest box and reached my hand inside to pull out some old leaves. This was not a good idea. In addition to the leaves, I also grabbed a very annoyed grey squirrel. The startled animal ran up my arm and out of the box, while I jumped off the ladder and sprinted into the house…to tell my wife I had another job for her to do.

From a distance birds appear to be sleek and beautiful, but they can carry lots of mites and other itchy things. Consequently, it’s a good idea to wear gloves when handling old nests. (That’s another lesson I learned the hard way) Also, nests often contain a fair amount of fine dirt and dust, so be sure to stand downwind, or you could spend the rest of the day rubbing your eyes and spitting. (Yup, I’ve made that mistake, too.) Another fact about birds’ nests is that they can be surprisingly difficult to remove. You might think pulling a nest out of a bird box is as easy as taking a reheated burrito out of a microwave, but that’s not always the case. I’m not sure why, but a nest can often stick to the inside of the box. I typically use a putty knife to loosen the bottom and sides of the nest, much in the same way a cook might use a spatula to help get muffins out of a muffin pan. (Hmm, burritos, muffins…I think I need to take a break for lunch. I’ll be right back.)

Folks often question why we need to clean out birdhouses in the first place. After all, no one cleans out the natural cavities. Yes, this is true, but natural cavities aren’t always reused and our goal is to have our boxes occupied every year. Some birds, such a chickadees, tend to avoid using cavities that contain old nests. One of my favorite nest boxes has fledged baby chickadees every year since I put it up in 1994. That likely would not have been the case if I (my wife) hadn’t cleaned it annually. And remember those mites I mentioned earlier? Baby birds have a better chance of survival if the mites from a previous nest aren’t waiting for them the minute they hatch out. Some people wonder if nest boxes need to be disinfected. Good question. Usually, after I clean out a box, I leave it open for a few days and let it air dry and allow nature do the disinfecting. Some experts disagree and recommend washing the inside of the box with a mild bleach (or vinegar) solution. Massachusetts Audubon suggests using a solution consisting of nine parts water to one part bleach. I’m sure this is a good idea, but nine parts water to one part bleach is way too much math for me to deal with. I take the lazy, math-free way out and let things air dry.

Ease of cleaning is one of the most important features to look for when buying or building a birdhouse. Unfortunately, many manufacturers and some consumers ignore this important feature. More often people ask for a box that has less to do with the birds’ needs and more to do with yard décor. Birdhouses in the shape of churches, lighthouses or even log cabins are far more popular than they should be. (Those log cabin birdhouses must be for people trying to attract Lincoln’s Sparrows. Get it? No? Fine, but hardcore birders and presidential historians will be LOL…maybe.)

Early March is a good time to double-check your boxes, Leon, but don’t wait too long. Eventually, you’ll run the risk of interfering with early nesting birds. And remember, when you clean your box you should wear gloves and stand downwind. Also, if you find any mice or annoyed squirrels in the box, get your wife involved. It’s a fun way to put the “surprise” back in your marriage.