Nesting season is hazardous for birds, and there are many predators that consider eggs, hatchlings and even brooding adult birds a tempting, tasty meal. By taking steps to protect bird houses from hungry predators, it is possible to help nesting birds raise their families in safety.
Bird House Predators
Many different predators will target bird houses for an easy meal. The most common culprits include:
In addition to these common bird house predators, larger birds will also often threaten other nesting birds. Jays, grackles, crows, starlings, magpies and other large birds are partially avivorous and will happily take advantage of eggs and chicks as an easy food source if they can get into bird houses or nests.
Make Bird Houses Safe From Predators
While it is not possible to make many modifications to create safer nesting areas for birds that nest in trees and shrubs, cavity-nesting birds can be helped with a wide range of tactics. Birds that nest in bird houses are subject to the safety of that house, and by making the houses more resistant to predators, the parents and their chicks are more protected.
Techniques to make bird houses more predator-resistant include:
- Hole Restrictors: Many predators will claw or chew on bird house entrance holes to enlarge the holes for easier access. A hole restrictor is a metal plate that is fastened over the existing entrance hole to prevent that enlargement, thereby permitting only birds of the appropriate size to enter. This also helps prevent larger birds from using the house, either as predators or to usurp the nesting site. Hole restrictors are also a great way to adjust bird houses to have the proper entrance hole size for only the desired bird species.
- Tube Entrances: Another way to make it harder for predators to reach inside a bird house is with an elongated tube entrance. Many cavity-nesting bird species don't mind a longer entrance, but predators lack the extra reach necessary to stretch through the tube and endanger the birds inside. A simple piece of PVC pipe attached over the entrance hole is sufficient, and bird house manufacturers also offer tube entrances fashioned like hollow branches for aesthetic appeal and camouflage.
- Roof Size: Large predators such as squirrels, cats and raccoons may sit on a bird house roof and reach inside to attack the nesting birds or chicks. A longer roof that extends 5-6 inches in front of the house provides a built-in baffle to limit predators' reach and prevent them from accessing the entrance. Longer roofs also provide better shade and rain shelter for the entrance hole to keep the house cooler, drier and more comfortable for nesting birds.
- Baffles: Predators can easily access bird houses by climbing up poles or approaching down trees from above the house. Installing metal baffles both above and below the house as necessary will help minimize predator intrusions. Metal baffles are more difficult for predators to climb, and attaching a bird house to a metal pole will provide even more protection.
- Removing Perches: A perch on a bird house is more than just decorative, it is dangerous. Birds do not need a perch to move in and out of the house, but a predator will use the perch as a convenient handhold to steady themselves when they raid the nest. By removing any perches or similar ornaments that predators could cling to, you make it more difficult for them to access the birds inside the house.
- Safe Mounting: Properly mounting a bird house not only makes the house more attractive to nesting birds, but it can help safeguard the house from predators as well. A properly mounted house will be at least 10 feet above the ground and away from any trees or shrubs predators can use to jump onto the house. Similarly, avoid placing a house near an arbor or trellis that predators can use to climb closer to the house, and avoid locations with heavy shrubbery that can conceal predators.
- Predator Repellants: Different products that can be used to discourage predators from approaching a bird house. Hot pepper sprays or other products with strong smells and tastes can be applied around bird house entrance holes, on bird house poles, on nearby plants or on the roof of the house, wherever predators may come close to the house. Songbirds do not have strong senses of smell or taste and will not be put off by the products, but predators will be.
While there are many ways to make a bird house safer, making the entire area less welcoming to predators can help safeguard nesting birds as well. Easy options include:
- Trim shrubbery to remove cover that can conceal hunting predators.
- Remove foods for predators, such as nuts for jays, so they do not feed nearby.
- Cover compost piles and ensure all trash is disposed of properly so predators are not attracted.
- Take steps to discourage feral cats and always keep pet cats indoors.
- Avoid handling the house as much as possible so as to not leave behind scent that can attract predators.
- Winterize bird houses so small predators don't claim the house each winter for their own use.
It can be disheartening to see a predator invade a bird house and a feathered family torn apart, either figuratively or literally. By taking steps to make bird houses safe from predators, however, it is possible to minimize the risks birds face when they take up residence.
Photo – Snake in a Bird House © Matthew