In the UK, house and tree sparrows are a native species and unfortunately also happen to be on the conservation red list. This means efforts to conserve what's left of a species is a high priority and that the breeding population has reduced by at least 50% in the past 25 years.

NB: House sparrows aren't native to the US and often out compete native birds that are vital to their own ecosystems so do some research before designing a bird house suitable for a specific species. Conservation charities and bird watching groups are both great resources and can be great communities to be a part of if you get into it.

Creating suitable habitats for birds directly counters the habitat destruction that's causing their population to nose-dive. Additionally, people care about things more when you put that thing in front of them, so drawing native birds to your local area creates the opportunity to introduce people to grassroots conservation efforts and perhaps inspire wider change around your community.

Additionally, we'll be using an ESP32 to create a spy camera so that we can monitor the birds without disturbing the nest. This way we can watch the chicks from egg to first flight. This is fantastic for knowing when it's safe to remove and clean the nest box but mostly allows us to show off pictures of the bird family living inside.

You can use alternative wireless cameras since the enclosures design includes a hollow space that you can easily set to the correct size yourself. Pi zeros have a range of cameras including night vision, so you can watch the birds at night time. Alternatively, you could stick whatever kind of sensor you want in the enclosure and do something totally different.

Step 1: Tools and Parts

Tools

A 3D printer, or access to one through a printing service online.
A screwdriver, drill or hammer

Materials

Filament for your printer, if you have your own
Strong cord or wire, I'm using scraps of 2mm copper wire because I have it to hand.
Optionally, an ESP32 with a camera such as Adafruits ESP-EYE . This is by no means necessary and it is by far the most expensive part of the project. Alternative wireless camera set ups work great too.
Power supply for the camera and wireless board. I'm using 18650s.

Step 2: Adapting the Tinkercad Design for Different Birds - Part 1

Different birds are different sizes, a large bird can't fit through a smaller hole than a small bird and a larger bird can often chase a smaller bird off. This means the size of the entrance allows us to be somewhat selective about which birds we want to live in there.

I'm including a list of some UK and US birds and the smallest holes they can fit through, this information is easy to find for other countries too. Conservation charities and bird watching groups keep this information readily available. Take special note if there are invasive species in your area because it could save you a lot of trouble to target smaller birds than the invasive species are.

Though, once you have the target size for your entrance hole you can click on the tinkercad above to begin editing your own version. You'll see there is a large "hole" cylinder at the front that you can move and edit, stretch or squash to your required size. You may need to reposition it after resizing it. Also, there are 4 holes in the sides of the box towards the rear that allow you to run wires though the box and fix it to a fence post or tree as we will see in a later step. I'm using 2mm wire to fix mine to a tree. If you're using thicker wire you should enlarge those holes.

Lastly, you may want to scale the entire thing up or down depending on the size of the bird you're hoping will move in. Do this before finalizing the size of the entrance and wire holes because the holes will scale with the shape. When everything is set correctly, select all shapes and click "merge" in the top right of the screen.

Step 3: Setting Up the Camera

I didn't actually know how to set up a live stream feed from an esp32 before i took on this project, playing around with how to do it was actually the inspiration for the project. Techiesms is a youtuber who made a great tutorial on how to do it with blynk. I've linked that video on this step and I'm happy to answer any questions about setting it up.

Step 4: Adapting the Tinkercad Design - Part 2

Above are the two pieces that make up the top of the bird house. Now that you have your whole camera set up it's just a matter of measuring how big the space in the lid needs to be and selecting the cuboid "hole" shape, setting it to the correct size and merging all the shapes.

The second tinkercad is a screen that holds your electronics in place. It has an adjustable hole too, except it's for making a space that your camera lens can slide into. You might need to change it's position depending on the board and camera you use so double check your measurements before printing.

Step 5: Hanging the Bird House

A lot of this info comes from the RSPB, it's a UK based conservation charity that exists just to deal with conservation of wild birds in the UK so for UK readers they are a fantastic source, a lot of this information is general but it's always worth researching local species and their requirements.

Your first consideration should be predators such as cats, other birds and snakes. Physical barriers such as baffles and bird box plates might help but it's better if the predator is never able to reach the bird box after you hang it. Watch out for nearby fences that a cat could use to jump to the box and never add a perch to your box as they are unnecessary for the birds but make it easier for predators.

Secondly, different birds look for homes in different locations. For sparrows, tits and starlings that means 2-4 meters up a tree or fence. Most birds will not nest close to other birds however sparrows will happily nest close to other sparrows. Additionally, never place a bird box within line of sight or close proximity to a bird feeder, as this will attract other birds that disturb the nest and possibly cause the nest to be abandoned.

Thirdly, make sure the box is never in direct sunlight. If there is no shade covering the box, face the entrance between north and east if you are in the northern hemisphere or south and east if you are in the southern hemisphere, thus avoiding direct sunlight at it's strongest parts of the day.

Now that you know where your box is going, thread 2 lengths of wire through the holes in the side of the bird box, don't worry that it isn't flush with the bird box, the gap will help the baby birds to climb out when they leave the nest. Ask somebody to hold the bird box in position as you wrap the wire around the trunk of the tree or post and cross the wires at the back, twisting them around each other to secure the wire. Tug on the bird box gently and if it doesn't fall from it's position it's secured and ready.

If you are fixing the bird box to a fence instead of a tree you might prefer to skip the wires and screw/nail the bird box in instead, you're free to edit the bird house model in tinker cad for such a purpose but be wary of drilling/nailing the box to a tree as that could damage the tree.

Step 6: Bonus: Bird Feeder

Step 7: Watching Birds in the Nestbox

I've not yet seen any sparrows in the garden since hanging the box, The picture above is a bird my partner spotted whilst I was hanging the box that I got some quick pictures of.

Be patient though, never open the box unless you are sure there's no bird in there.disturbs nests get abandoned and this often includes the chicks who will starve without care.

Best of luck

Introduction: Smart Sparrow Homes