Buzz And Flutter: bird box entrance hole size

Saturday, 21 March 2020

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Another Spring is here along with yet another attempt to rent the bird house on the old Manitoba Maple tree. Many years ago, I built two oversized boxes in the hope that Eastern Screech owls would nest in them. No dice! Each winter the owls do use them for roosting and as a larder but they are not satisfied with the location for raising a family. Too public, perhaps?

Anyway, White-Breasted Nuthatches always show a keen interest in one box in particular. Unfortunately, every year they are out-competed by squirrels and/or European Starlings. This Spring I decided to lend the nuthatches a hand by customizing the box just for them. I made a new front with a smaller box to fit inside the larger box. All of the books and websites I consulted said that the entrance hole should be 1 1/4 inches wide for White-Breasted Nuthatches. So I drilled to this measurement and attached a squirrel proof metal guard, which was also 1 1/4 inches wide.

Custom built for my White-Breasted Nuthatch friends.

Up the fourteen foot ladder and installation completed.

The metal guard means "Squirrels Need Not Apply".

The small opening means "Starlings Need Not Apply".

The faux-bark is a bit cheesy, but the interior is brand new! Do have a look!

Days went by and I only saw one nuthatch, after much struggle, enter the refurbished box. Shortly after, it struggled equally hard to exit. I took a video of another nuthatch trying and failing to enter. Obviously, my resident 'McNutties' are too large for that diameter.

The following video clearly shows that the recommended entrance size is just too small!

So, up the ladder again, and down with the box for alteration. I enlarged the hole a little and added a 1 1/2 inch center metal guard. I also removed the perch. Bingo! The McNutties love it! I expect they will be moving their furniture (bits of bark) in soon.