People love birdhouses as they are a great way to attract birds. But sometimes a unfortunate tragedy develops when a predator is able to attack and kill the baby birds, and sometimes the mama bird. Unprotected birdhouses, or nest boxes can often turn into a take-out meal for raccoons, cats, or snakes. In this article I’ll show you how to make your own entrance hole guard from hardware cloth, step by step.
But this predator guard is very effective at protecting almost any style of nest box or bluebird house. It basically prevents the cat, raccoon, or squirrel from being able to reach into the nestbox through the hole.
- 1/2″ hardware cloth
- #8-1/2″ screws
- #10 washers
- Our Plans (print friendly pdf)
- Leather gloves
- Needle Nose Pliers
- Wire Cutters
- Scrap 2×4 for bending
- Drill & bits
- Screwdriver or wrench
Step by Step Guide to make a Birdhouse Entrance Hole Guard
1 – Unroll some hardware cloth, and weigh it down so you can cut out a 7″x18″ section. Use wire cutters to trim out the rectangle. This takes a couple minutes. And don’t forget to wear your gloves!
2 – Trim a 1/2″ recess that is 3-1/2″ long, two times per the drawing
3 – Use a 2×4 to fold the hardware cloth into a box
4 – Using two sets of pliers, bend the tangs around each other so that the rectangular shape / cage is secure. Also, use the waste from step 2 to wrap around the seam, adding more strength
5 – Use your needle nose pliers to open up the two 6-1/2″ sections. This is the end that will get assembled to the bird house
6 – Install the Noel Guard around the entrance hole, taking care not to obstruct the hole. Drill pilot holes prior to attaching screws, as that will prevent wood from splitting. I find it easiest to hold the guard up to where I would like to install it, and mark where I will drill holes with a pencil.
7 – Attach the guard using #8 screws and #10 washers. I suggest you hand-tighten these screws, as the wood is less likely to split from over-torquing the screws.
Noel Guards are effective against predators
Any protection at all is better than none for birdhouses! Bird-watching societies have been recommending them for decades. And, there is plenty of scientific research to back up these recommendations! 
In particular, the Noel Guard can stop raccoon or cat from entering the hole. Their arms are not long enough to reach into the hole and get the babies.
Also, the sharp tangs may dissuade a snake from trying to get to the hole. But, one should consider using a conical barrier (squirrel baffle) or smooth stove pipe to stop snakes.
Should you protect your Birdhouse?
 – Bailey, R.L. and Bonter, D.N. (2017), Predator guards on nest boxes improve nesting success of birds. Wildl. Soc. Bull., 41: 434-441. https://doi.org/10.1002/wsb.801
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