Cats, whether they belong to you or your neighbors, should be kept away from birdhouses. Just the sight of a cat might cause adult birds to abandon their young.
Cats can be discouraged from using a birdhouse by mounting a 2 by 2 foot broad board of plywood on top of the birdhouse, leaving enough room for the cats to walk around without sitting on the plywood and upsetting the birds. The original roof can be pierced with spikes, the birdhouse can be enclosed in a cage, or the entrance can be guarded with wire.
Preventing cats from getting into contact with the birdhouse in the first place is the most effective method for keeping cats out of birdhouses.
To begin with, having a cat permanently perched on top of or nearby a birdhouse can cause the adult birds to become fearful and abandon the nesting box altogether. So, if there are any unhatched eggs or young birds in the box, they will be abandoned.
Because of this problem, you shouldn’t ever hang a birdhouse from a wall or fence where cats frequent.
A Bluebird house, for example, might only need one wooden pillar in order to stand.
Cats won’t be able to get into a birdhouse if you hang it from a thin wire, but it will be more difficult for birds to find it.
If you know for sure that cats will be drawn to the birdhouse the moment it is operational, you should probably forget about it and instead concentrate on attracting birds using feeders.
Protection from cats who like to perch on the roof of a birdhouse is the best approach to ensure that the cats don’t move in.
A broad plank of wood would be mounted over the birdhouse to prevent cats from getting inside. If you really want to keep cats from perching atop your birdhouse, you should nail spikes into the original roof or onto this wooden plank.
Cats shouldn’t be able to access the birdhouse through the entrance hole, as they might try to grab the birds that occasionally use it as a perch.
A ground squirrel resistant bird feeder cage can be used as a protective enclosure for a birdhouse. However, if you merely want to protect the birdhouse’s entrance hole from predators, you can do so with minimal effort.
Mount wood plank on top of birdhouse
Placing what I’ll refer to as a “cat baffle” on top of a birdhouse prevents cats from climbing onto the roof in the first place.
By inserting this plank of wood between the birdhouse and the sheet of wood mounted above it, you can keep the cat from reaching the birdhouse from the extra board of wood, but the cat won’t be able to reach the birdhouse itself.
Making a new backing piece of wood for the birdhouse is the first step in putting a 2 by 2 foot board above it.
Attach this backing to the birdhouse with screws, and utilize the protruding section to securely fasten the wooden cat baffle.
While you might need to install brackets to keep the birdhouse at a 45-degree angle, no additional support or footing is required to make room for cats to enter the structure.
A bottom or below the birdhouse wood plank guard to keep cats from getting on the birdhouse is not effective, so don’t bother with it.
Cats can be tolerated on top of a birdhouse because they waste time there, but if a bottom plank is used, the cat will use that to get access to the birdhouse by clawing through the opening.
Nail in multiple spikes on roof
Having a cat around is a surefire way to drive away any nesting birds, so I won’t blame you if you choose to keep your feline friend off the birdhouse roof.
Because of this, it’s not a bad idea to construct a roof that prevents cats from getting inside.
To prevent cats from settling on the roof of the birdhouse, you need just hammer in the sharp ends of dozens of nails upside down; the cats will injure themselves trying to get off the roof.
Using an electronic grinder or hand-held cable cutters to remove the points of tiny galvanized nails is not a straightforward task.
The next step is to evenly distribute the spikes around the ceiling, perhaps every half an inch, so that cats can’t sneak their paws in between them and make the method worthless.
It all depends on where you put the birdhouse in your yard or outside your property, as a cat may choose an alternative perch, such as a fence or branch, instead.
Then, if you’re not too worried about safety, hammer in a pile of nails with the pointed end facing up; the cats won’t get wounded since they won’t bother, and nobody else is likely to get hurt because normal nail tips are dull.
Cloak birdhouse in cage
The other way to prevent cats from entering birdhouses is to keep them at least a foot away, in whatever direction they may approach from.
This plan necessitates installing a caged bird feeder, designed to deter squirrels, directly on the ground. The only difference is that we plan to repurpose this rather large cage by placing it atop the birdhouse.
The birdhouse is attached to a wall, fence, or even a strong tree trunk at an angle, rather than directly above.
The cage will be fixed on the backing of whatever the birdhouse is bolted into, such that the birdhouse is centered within it.
It’s not too heavy, but you might want another set of hands just in case.
The backing that the birdhouse is attached to must be large enough to accommodate a potential 2 by 2 foot cage.
Easy peasy if you first fasten the birdhouse to a board of similar or greater dimensions, preferably one of treated exterior plywood.
With the birdhouse hooked or screwed onto the plywood’s dead center, you can next mount the squirrel resistant cage onto the board using stables or nailing in comparable galvanized staples with a hammer.
The inhabitants of the birdhouse can come and go as they want with the help of a cage that has spaces large enough for them to sneak through.
Affix long wire guard to entry hole
The final option is to install what amounts to a predator guard over the opening of any birdhouse.
Steel metal plates or a substantial piece of wood can be used as predator guards, but either way, an opening of comparable size is maintained.
Because of this, the range of any predator attempting to enter the home and cause harm is increased by a factor of two.
However, this type of predator guard will not be used in my plan.
No, this time we’ll employ the effective — though unattractive — deployment of an expanded wire cage guard encircling the entry hole.
This long cage of wire will look like a repurposed suet cage feeder, and its square or rounded shape will deter any predator from climbing onto the roof of the birdhouse.
It would be challenging to create such a gadget, but purchasing one would allow you to quickly attach it to the front of the birdhouse.
Keep in mind that there is no standard size for a birdhouse entry hole, so make sure that this metal wire cage is placed far away from the entrance.
When a decent distance is all that stands between a cat and your house, the cat can’t just claw at the entry hole.
Cats won’t be able to perch on the end of the wire guard outside the birdhouse, but birds will have no trouble flying in and out.
To sum it all up
Birds will abandon their young if cats are allowed near their nests, therefore it’s important to find a technique to keep them out of birdhouses.
Cats shouldn’t be allowed near birdhouses at any time.
Keep your cat far away from your birdhouse since birds won’t nest in a box if there are any cats around.
Also, birds that currently nest in birdhouses won’t tolerate a predatory cat lurking nearby to prey on them or their young.
The best way to deter cats from the birdhouse while also keeping them at bay is to install what is known as a cat baffle in the area just above the birdhouse.
It would be up to you to fashion this board out of wood and figure out how to attach it half a foot above the birdhouse. The board should be at least two feet broad and should measure in at least that many inches.
Not too low that birds can’t fly out of harm’s way, and not too high that a cat can’t jump up and knock it over.
Leave the cat baffle as-is, but please do your best to prevent cats from climbing on top of this do-it-yourself cat baffle and thereby defeat its purpose of keeping cats away from birdhouses.
In order to prevent cats from standing atop this sheet of plywood, the sharp ends of galvanized nails should be snipped off and the nails should be hammered in with the upturned side facing down.
If you’d rather not build your own birdhouse predator-proof, you may always attach a wire metal cage to the opening.
Alternatively, you could install the same thing that hides ground-level bird feeders inside a cage, which would then obstruct views of the birdhouse you’ve installed at its center.