Keep birds and their eggs safe! Here's why a predator guard is a great option for deterring unwanted visitors to backyard birdhouses.
Spring brings much joy to backyard birders across the country: warm weather, the return of long-distance migrants, and — eventually — nesting season and baby birds. With that said, sometimes it’s not as simple as waiting until you see tiny, curious heads peeping out of a birdhouse’s opening. Plenty of predators can threaten baby birds and bird eggs, including those that attack the nest. Here’s what to know about a birdhouse predator guard, and why you need one.
What Is a Birdhouse Predator Guard?
A birdhouse predator guard prevents certain types of predators, such as raccoons or snakes, from taking eggs, baby birds, or even adult birds from their nest. In making it difficult to reach into the house or climb the pole, it encourages those predators to look for food elsewhere. Certain guards also stop less threatening backyard visitors, such as woodpeckers, from widening a birdhouse’s hole.
“Predator guards are a helpful tool to install on or with a birdhouse to keep natural predators from entering the nest box and harming the eggs or young birds,” Megan Oberholzer Hatton, manager at Wild Birds Unlimited Charleston, says. “They work to deter predators, such as snakes, squirrels, and raccoons from pursing a nest as a viable food source.”
What Types of Predator Guards Exist?
Megan mentions three different guards birders can install on their houses: a baffle, a metal mesh snake guard, and a metal entry hole guard.
A baffle attaches to a pole, so it stops critters from climbing to reach into the house. “This is the most effective deterrent for snakes and raccoons,” Megan says. Baffles can also be useful on bird feeders, where they discourage gluttonous critters from stealing birdseed. Many variations of baffle guards exist: it’s best to choose the one recommended for the specific creature you’re trying to deter.
A metal mesh snake guard — also called a Noel guard — attaches outside of the house’s entrance and makes it difficult for snakes to enter the birdhouse. “It has raised, spiky edges facing outward from the entry hole,” Megan says. Other methods of discouraging snakes include specific, targeted baffles (cone-shaped, PVC pipe, or stovepipe), and attaching wire mesh beneath the nest box.
Metal entry hole guards attach to the house itself. “This helps to reinforce the wood to deter squirrels and woodpeckers from widening the entry hole and stealing the nesting space,” Megan says.
The fourth type, a tube hole extender, extends the entrance of the birdhouse outward from a hole-shaped attachment (i.e., a plastic tube). This prevents predators from reaching into the house, but these guards can also pose a problem for birds. While some enter the house without issue, others might find it discouraging and nest elsewhere.
A better alternative is a wooden block extender. This serves much the same purpose as a tube, but it shouldn’t deter nesting birds. Similar to the metal entry hole guard, it attaches over the box’s entrance hole. Its thickness “extends” the entry by the size of the block. On some next boxes available for purchase, especially houses for bluebirds, block extenders may be pre-built into the design. You can also build your own or buy one separately.
How to Use a Predator Guard
Which guard you should use depends on the design of your birdhouse and which predators you’re trying to deter. If your birdhouse sits on a pole, you can try a baffle. If it’s attached to a fence or tree, you can choose the mesh guard or hole extender. These guards can also work on pole-mounted houses. The metal entry hole guard and wooden block extender can be attached to a variety of birdhouse styles and even on swinging wren houses.
“Both the baffle and the snake guard are easy to install for new birders,” Megan says. She mentions that new birders can also stop by local stores to ask experts how to protect the birds in their backyard. Guards are available from a variety of retailers, including Wild Birds Unlimited and Duncraft. Other, more elaborate guards can require a bit of elbow grease or know-how to put together, but guides exist online to help beginners.
When Should You Use a Predator Guard?
Megan recommends keeping the guards up throughout the year, although they’re most crucial during nesting season. “I would suggest keeping them on to deter predators, especially snakes, from using the birdhouse as a wintering home,” she says. “If they know they can access the nest box once, they will continue to try year-round.”
Are Predator Guards Always Effective?
It’s important to understand that no predator guard has a 100% success rate. What works for one birder won’t necessarily work for another. External factors can also affect whether a nest box suffers predation. Location of a birdhouse, weather, availability of food (for snakes, raccoons, etc.), competition from other native or non-native birds such as house sparrows, and region of the country all contribute to the success of a nest.
However, it’s also important not to get disheartened. “Do not let the possibility of predation problems prevent you from putting up a bluebird box,” the North American Bluebird Society writes.
There are plenty of troubleshooting tips that can help you fend off unwelcome guests. With enough time, effort, and out-of-the-box thinking, it’s possible to create an environment where your birds are safe.
