This article will cover the main things to take into consideration when thinking about how to protect birds and bird houses from predators, which is important if you don’t want the birds you would really like to attract to be scared away.
Bird houses most commonly attract species of birds that fall into the category of cavity nesters. These are birds that will find holes, crevices and depressions in which to build their nests. Some examples of cavities, either natural or man-made, that are suitable for this purpose include knotholes in trees, hollow stumps, and the nooks of houses.
Certain species – woodpeckers, for instance – create their own dwellings by using their bills to carve out holes in trees. All others (referred to as secondary cavity nesters) have to make use of any pre-existing spots that they can find.
This creates a situation in which competition over a nesting place, which might include your bird house, is fierce. Consider, also, the threat posed by other animals that might desire the dwelling place, or the bird eggs inside, for themselves.
How To Protect Birds And Bird Houses
To plan for the safety of the birds that you want to attract, first consider the entrance hole to your bird house. This should be no larger than one and nine-sixteenths inches in diameter.
A wider hole will allow in starlings, which are imported and aggressive birds that might claim your nest box and scare away smaller species. Just make sure your hole is still at least an inch and a quarter in diameter, as this will allow the birds that you desire to enter – and without excessively wearing out their feathers while doing so.
Also choose a box with enough depth to allow for a bird’s nest to sit well below the entrance hole. This will make it less convenient for other kinds of predators to peek in.
House sparrows are also aggressive competitors, and they are small enough to fit into any opening that other birds are able to use. One way to deter them is to plug up your box during the winter, as house sparrows tend to claim bird houses early. Another option is to simply remove the nesting material that they bring into your bird house. You may need to do this repeatedly until they give up, as these birds can be persistent.
If you notice that nesting material has been pulled out of your bird house, or there are claw marks on it, these could be signs that at least one raccoon has been visiting. Mounting your box on a metal pole is the best way to make it inaccessible to raccoons.
Coat the pole with a thick layer of grease (automotive or marine grease works well), at least once in the spring. This creates a slick surface that these animals can’t get a good claw hold on. Putting a baffle over the bird house entrance (a wood block with a hole in the middle the same size as the entrance hole) can also make it hard for raccoons and other predators to get their paws into the box.
You can even buy, at pet supply stores, more extensive devices – three inches in length, or longer – that can be attached to the entrance hole. Just be aware that the birds you’re trying to draw with your bird house may not always be able to adapt themselves to such entrances.
The same predator guards that work for raccoons can be effective with cats, also. Cats are typically more active when fledglings, which are birds that are old enough to fly but are still dependent upon their parents for food, have left the nest. It’s a good idea, then, to keep your own cats inside until the fledglings have moved on.
Reinforcing your bird house entrance with a metal plate will make it impossible for squirrels to chew and enlarge the hole. Mice might want to take up residency in your bird house, especially during the winter, so make a habit of cleaning your box out in the spring (if you don’t have it plugged up already) and removing any nests. Mice that have been shooed out of a bird house usually don’t come back.
If you enjoyed this guide on how to protect birds and bird houses from predators and found it useful, you might want to check out some of our other articles including our guide to squirrel proof bird feeders.