Template: Building a Barn Owl Nesting Box: Difference between revisions

Revision as of 17:29, 27 February 2023

Building a Barn Owl Nesting Box

There are many plans available on the Internet and if you are reasonable with DIY projects, you should find this fairly simple - getting the box up the tree and fitted will be the challenge!

We have built two Barn Owl Boxes, one based on the plan found on the Barn Owl Trust website; you can download the hi-resolution plan here, the second Barn Owl Box was based on a simpler generic plan, which does not include the essential landing and exercise platform, download the hi-resolution plan here.

Construction materials

Cost obviously a concern nowadays, so unless you can afford 18mm marine ply, which is the ideal wood, but expensive, I would go for Oriented Strand Board (OSB). It's easy to work with and is reasonably water resistant and rot proof.

Screw and glue all panels. Use an acrylic sealant inside the box to seal any poorly fitting joins. Treat the outsides only with a wood treatment such as fence paint. Cover the roof with roofing felt, or if cost is important, a few layers of thick plastic sheeting such as Damp Proof Membrane. Check there are no screws protruding inside of the box.

Do not rely on screws alone to secure mounting bars and external fixings; that's how our original box is so badly tilted, the plank used to level the box was screwed into the base of the box and did not hold up to strong winds. Use coach bolts combined with large washers to ensure any mounting points stay on the owl box forever.

Once your box has been mounted in its tree any changes or modifications, such as adding cameras inside the owl box are likely to be very difficult to make because access can be very challenging. Also, as with our box, it appears to have been constantly occupied!

Drainage and ventilation

You can guarantee that water will get into the box, however well you make it. Our first box even had a large egg-shaped hole in the back panel thanks to our local woodpeckers, so ensure you drill some 15mm holes in the base to enable water to drain out.

I would also suggest some ventilation holes in the sides of the box too. In May last year we had two adult owls and two young fledgling in the box at the same time. It's going to get quite fetid in there if there is not adequate air circulation!

A benefit of our accidental tilt, see pictures below is that it enables the owls to grip the inside of the box and stand and look out of the entry hole. Our camera system shows they do this for hours on end, day and night. It wouldn't take much to modify your box to do this; a few slats inside the box under the entry hole, or maybe even a layer of chicken wire would be enough. The benefits are enormous; both for the owls looking out and for us to be able to see the box is occupied, even from a distance.

Considered wisdom is to have a removable panel to allow for cleaning; however for many reasons I would not worry with this. Firstly our box has been occupied continually from the time we first discovered that owls were nesting in our box. Access to the box is exceedingly difficult as it's above a 30 year old bramble patch and a small dyke and due to the movement of the box, I would not be happy resting a ladder against it, even though this was built into the design. I'm also not the least bit comfortable 6 metres up a ladder trying to unscrew panels on the front of the box. If you think you will be cleaning out your box, I would position a hatch on the side of the box, then you can just rest your ladder on the tree and not have to get to the front of the box.

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  Plan for building a barn owl tree nesting box
  click image to access larger hi-res versions

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  Mark the panels out directly onto your OSB sheet

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  Cut the panels out with a jig-saw or circular saw

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  Almost finished, showing the cleaning panel

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  The completed owlbox ready for treating

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  Being checked by our buildings inspector 😸

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  A much simpler owl box that is very easy to build
  You will need to add an exercise / landing platform for the young