From time to time I post advice on evicting squirrels from screech owl nesting boxes. 

Evicting the squirrels is especially important this time of year, with nesting season around the corner.

My preferred method is to bang on the box to get the squirrel to leave, then remove its nesting materials.  Try to evict the squirrel before it has babies or wait till they have fur.

The drawback to removing the nesting materials, of course, is the need to use a ladder (I had to ask a friend because of my broken ribs).

Here are two other tips.

Mark Madden writes:

Squirrel evicted. Made the hole smaller,  too --  3 inches round. hope this makes it inviting for screech owls.

Thanks for mentioning this!

Another reason to make sure the opening is not too large is to make sure Wood Ducks don't try to nest in the box.

Rob Rollans writes:

Recently a really aggressive squirrel took over my friendly owl (Hoover)’s nesting box in the middle of the night.

I am fortunate in that I can see the owl’s nesting box from my kitchen
window (no owl cam) so it’s easy to know when the squirrel is there because he frequently pokes his heads out.

I tried beating the box with a stick from the top rung of my ladder but this had no effect and I very nearly bit the dust a time or two, then I decided to try to drown him out.

With my sprayer...set to “jet,” I sprayed the water directly into the entrance until the invading squirrel shot out like a rocket!

All it took was two times and he hasn’t been back!