WARNING: Before you'll eagerly start to read and also to prevent you'll feel like cheated at the end I just want to warn everybody who doesn't live in Eurasia or North Africa that this nest box Instructable is custom design for the Little Owl (Athene noctua) - a tiny owl that only lives in that part of the world.
You'll not find it in North or South America, Indonesia & Australia. Weird enough you might spot it in New Zealand since it's being introduced there some hundred years ago.
If you're living in the New World you can keep on reading. You might find some general nest box building knowledge as well.
So let's talk about that bird & the reason why someone would build a box around it.
The Little Owl is - guess - a very small owl - like the size of a Blackbird. Don't know the size of a Blackbird? In that case I'm pretty sure you'll know the size of a 'Big Mac'. Well, our Little Owl and your Big Mac are almost the same size, with that important difference that the owl has a slightly less fat percentage. Kiddiiing!!!
Athene noctua is quite common in our agricultural landscapes and keeps performing well in the more urbanised areas. We call it 'stone owl' because it often breeds in wall cavities of old farms. Other breeding spots are natural holes in old trees and once I even found a bunch of chicks in an abandoned car. It's an all-eater: insects, worms, amphibians, mice & even small birds - everything goes inside this little warrior.
Owls swallow their prey intirely - opposite to raptors who tear their prey apart and eat just a part of it. Once digested they spit the non-digestible parts like bones, hairs and exoskeletons out in the form of pellets. Each owl species has its own type & style.
When I was younger I took hundreds of those balls apart to learn more about the owls diet. Yes, that's what we did when we were young. There was no internet, no facebook and no Instructables. And life was funny, anyway.
Like I said, Little Owls use natural cavities to breed - stuff that's more & more difficult to find in our 'clean' landscapes. Trees don't grow old anymore, when they're damaged by storms they are removed, old walls are repaired etc. Our world is losing a lot of authenticity...
So if we want to keep this small guardian of our pastures alive it's not a bad idea to provide them some help.
An artificial way to keep the populations healthy? Of course. But it was also artificial to destruct their environment. So let's do something back by providing them some artificial nests - they'll love it!
The pictures were taken by Steven Deridder during a monitoring program about ten years ago. Hundreds of volunteers checked every square kilometer in Flanders during wintertime, puttting every single Little Owl on the map. Combined with breeding data this gave us a detailed view on the distribution of the species in the country.
Step 1: Choosing the Spot
How do you know if there are Little Owls in your region? Keep your ears open. From november to april they're quite loud, defending their - rather small - territories, searching a partner, renewing old bands and having a lot of fun.
How do you recognise their sounds? Google & compare! You'll hear them sooner then you see them because they melt easily in the landscape. They often start yelling after sunset and go all night through.
Wanna know more? Contact local birders where you live, there's surely at least one owl specialist who can help you further.
Little Owls are often spotted in what we call 'small scaled landscapes' - a mix with pastures, fields, hedgerows, solitary trees & orchards. A high structural diversity often results in a high biodiversity and in such man-made environments we find the highest concentrations of that species, sometimes with several couples per square mile.
Last year we moved in a small old farm, and the past months we hear those owls almost every day. Past week we were lucky to see a couple in our pasture and so we decided to present them an artificial nest - in case they didn't decide yet where to drop their eggs. I managed to make a picture of both - surely the best 'rotten shot' I ever made - when they were squatting an old cherish tree.
Since that tree provides a good view to a mice-rich pasture next to it we decided to put the box in that tree.
Some put boxes in trees, some prefer to fix it to the wall of a building. It's not rocket science, rather common sense. Good to know is that those owls like to have a good view from their nesting spot. Easy to spot potential predators & potential stuff to eat.
If you want to help this species and you don't have a garden, you can contact local farmers and ask them if they don't mind that you'll put a nesting box somewhere on their property. Again, contact local birders and ask them if there are running nest box programs. Better to communicate a bit too much than not enough.
Step 2: Building a Balcony
So we chose to put the box in that famous tree.
The best way to fix a box in a tree is to fix it to a platform. Young owls love to observe the world from a distance and providing them a balcony is doing them a huge favor - it's also nice to see those chicks staring at you. It also prevents them to fall on the ground when they leave the box for the first time. Young owls climb before they fly and a fallen chick is an easy prey for cats & predators.
Building a platform in a tree is basic survival enginieering. Start building a triangle with some branches between existing forks, 3 or 4 meter from the ground. A triangle is a solid structure that won't move once fixed in place between the branches of the tree. Solidify it with screws or rope, but don't screw in the tree! You can use inner tubes to secure it to the mother tree but in theory you'll even don't need to. Use a piece of plywood or some planks to make the platform and screw it to the structure.
1/2 square meter (2x2 feet) is largely wide enough.
Step 3: Birds in Da Box
No nest box without a box. No need to have a plan - in nature not two natural holes are the same either.
Here's some advice:
- use non threated wood
- keep it simple & sturdy
- make the interior something like 30cm wide & 60cm long (1x2 feet)
I build it from scratch and the result is not worthy a woodworker, I know. But it's a nice design and it's rock solid, so I'm pleased with the work done. This kind of build is very nice when you're in a hurry. Nu glue no screws, only a bunch of raw planks and a fistful of nails.
Most people use plywood, but my experiece with plywood is that it has the bad reputation of releasing toxic vapors for a long time, making it less favorable to use in nest boxes. Unthreated wood is best. No need to make it a masterpiece. Function before beauty. Don't worry if the planks don't fit watertight together, a bit of ventilation in the babyroom is necessary to avoid condensation or overheating.
I made it maybe a bit too simple - with no removable flanks or roof - because I don't feel the need to look inside the box every day.
If they really start breeding you'll see it. The male will fly over & out to feed his wife and once there are chicks the hauling frequency will boost. Those chicks will start yelling for food, yelling to each other and yelling for more. After a month or so they will leave the box and you'll be able to observe them all day.
No need to disturb them before. Minimal interference.
Most people make the roof removable 'to clean the box every year'. Natural holes aren't cleaned neither, so I made the box in one piece. Less is more.
Best is to place the box during wintertime to give the owls the time to discover, explore & evaluate. Mid march is maybe too late, we'll see.
Step 4: ... and the Chicks for Free
Make the entrance at the side of the box and use a clock drill to make an opening with a diameter or 60-70mm (2-3 inch).
Little Owls like to drop their eggs in complete darkness, so you'll have to avoid that daylight enters by the entrance. Making a separation with a second hole in it is an option, I provided just a half separation. Most of the time this is enough.
I drilled a second hole in the roof - just a peep hole in case of - and fixed a plywood sheet on the roof to prevent that rain would drop inside the box.
The bottom was closed with a piece of alubond - inert stuff that won't rot when the owls will drop their excrements & pellets on the bottom of the box. Owls are dirty creatures, believe me.
My wife put a handful of wood scrapings in the box. If they like it they'll use it, if they don't they'll remove it.
Don't paint it, don't oil it. Let it raw. It will last 10 or 20 years. Make a new one once the old starts to fall apart.
Step 5: Box Meets Platform
When the box is done it's time to fix it to the platform. The orientation is simple: the nest entrance must be on the opposite side of the prevailing wind aka precipitation direction. No ones likes it when the rain poors in the box, the owls neither (that's also the reason why the roof has to go over the sides).
Screw it tightly to the platform & get out of that tree.
I know it's very tempting to look inside the box once it's been accepted. Try to limit this curiosity to a minimum - or install a remote controlled camera. Every time you'll open the box energy will be lost and when you peep a bit too much the parents will leave their nest, leaving the eggs behind...
Step 6: Exit Cats
To prevent cats or other predators to climb in the tree & have a good meal one last measure needs to be taken: making a no-pass zone.
With some sticky branches you can make a painful barrier that will keep every predator at a distance. Fix them with a rubber band to the mother tree and start admiring your work.
Thanx for watching & good luck with your project!