Removing Squirrels from the Owl Box

One unpleasant chore done: I've removed three very nice fox squirrels from the owl box. It always makes me feel like a bully and a scoundrel, but if the owls are going to nest in the box, the squirrels have to go. It's likely they'll be back in about a week, but the process of making the owl box feel like a dangerous place to be a squirrel is underway. In the meantime, when the owls poke their heads in the box, they'll see that it's available and should return to nest in it again this year.

Longtime readers may recall that I thought I'd solved the squirrel-in-the-owl-box problem a few years back when I placed a dedicated squirrel box in the same tree as the owl nest box. The idea being that a squirrel, or family of squirrels, would occupy the squirrel box, and their natural territoriality would cause them to repel any other fox squirrels that wanted to move into their home tree.

That worked for two years. I think the problem this year is that the squirrel family unit living in the squirrel box has been successful enough over these years that it has exceeded the (comfortable) capacity of the squirrel box, causing various family members to seek lodging in the next best place in the tree: the owl box.

That said, the number of squirrels in the owl box on any given night this winter has varied from zero to three. So, they must have at least one other nest site, presumably the squirrel box. I hope the three I had to pick on tonight will simply move back into that box, and write-off the owl box as a promising, but ultimately failed, experiment. Regrettably, I have no cameras in the squirrel box, so I can only speculate about the goings on in there.

Meanwhile, I encountered one of my owls one night ago, so they're around, just as one would expect. I'm also trying to have some significant upgrades in place for this season. As usual, I've left it a bit late (I was hesitant to spend the money), but I haven't yet fully proved that the new gear will behave as desired, so worst case, it'll be a moot point. Best case, I'll soon be in a flat-out race against time to integrate the new stuff. Wish me luck, and remember that the owl cam' has had to relocate to www.ChrisOwlCam.net.

Keeping Squirrels out of Owl Nest Boxes

I've been lucky this year and had no problems with squirrels in my screech owl nest box. Significantly, I think I know why.

Upper-left: Screech owl nest box in gray.
Middle: Fox squirrel nest box in green.

Though I've seen fox squirrels taking an interest in my squirrel nest box at various times, for lack of built-in video cameras or other instrumentation, I remained unclear as to what, if anything, was going on in there. However, lately, I've seen a good sized female relaxing on the horizontal board that serves the double-purpose of being a stand-off from the tree limb that keeps the nest box hanging vertically from a non-vertical limb, and as a walkway from the tree trunk to the entry hole in the bottom of the box. Around these parts, it's the right time of year for a fox squirrel to have her winter pups (well fed, as I expect my bird feeder ensures, a fox squirrel can produce three litters a year). Taking the afternoon air on that horizontal board, Mme. Squirrel could easily listen to her pups’ activity in the nest, while keeping an eye on everything going on around her, and from a position of complete safety, so it’s a good arrangement for her.

It’s gratifying to see the squirrel box serving its intended purpose, but I’ve also come to a reasonable degree of confidence that it’s serving an additional role: keeping other squirrels out of the screech owl nest box. The way it does this is very simple: fox squirrel territoriality. While they may tolerate each other to varying degrees in foraging encounters, they do not seem willing to allow other fox squirrels to setup a nest in the tree that holds their own nest. (Perhaps in really enormous trees there’s room for “my side; your side”-style compromise, but around here, even when a tree contains multiple squirrel nests, they all seem to be property of the same squirrel or matriarchal family group.) So, having an established squirrel nest more-or-less next door to the screech owl nest box ensures that it has a squirrel preventing all other squirrels from moving in, and you could not ask for a better, or more devoted, defense than squirrel self-interest.

So, if you've been having a problem with squirrels in your screech owl nest box, perhaps building and installing a squirrel nest box (similar dimensions to a screech owl box, but with an entry hole in a rear corner of the floor, and, perhaps, multiple internal levels) nearby is worth trying. And please report your results back here.