Western Bluebird
Bluebird Nestboxes
Water & Food for Bluebirds
Bluebird Nesting Behavior
Monitoring Bluebirds
Mountain Bluebird
Bluebird Resources
Abandoned Bluebirds
Bluebird Basics
Creating a Backyard
Wildlife Habitat
Attracting Barn Owls
Cats! Mild to Wild
Photo Credits
Contact
Predators & Pests of Bluebirds
Insect Problems
ANTS & EARWIGS can be controlled by placing a small amount of Tanglefoot on the hook of a hanging box or by placing a strip of cloth covered by a band of duct tape around the tree or pole and smearing the sticky Tanglefoot on the tape. Be very careful to place the band where the birds will not get into it. If the tree bark is rough, silicon sealer can be applied to fill in the gaps under the duct tape. The Tanglefoot needs to be renewed periodically.
WASPS & BEES may move into a nestbox. Wearing gloves, remove the wasp nest with a spatula in the evening or early morning when temperatures are cool and wasps are inactive. Wild honey bees may move in to a large barn owl box, in which case you can either try beekeeping or have them removed by a beekeeper. And if bumblebees move in, you may want to leave them be, as they will only use the box for a short while for nesting and are not aggressive.
POISONS: many pesticides are toxic to birds and should not be used near nestboxes.
Competition from Other Birds
HOUSE SPARROWS are the most undesirable competition for bluebirds. Non-native house sparrows are not protected and can be trapped and their eggs and nests removed. House sparrows can ruin bluebird eggs and young, and may even peck an incubating female to death. Don't feed house sparrows. House sparrows prefer small seeds, such as millet, cracked corn, and milo-- the stuff you find in common birdseed mixes. If you like to feed birds, try offering nyjer (thistle), as house sparrows and ground squirrels are not attracted to it. Or a less expensive way to feed birds is to plant lots of seed bearing plants.
HOUSE WRENS can enter bluebird nests and remove all the nesting material and destroy the bluebird eggs and young. House wrens prefer boxes in dense shrubbery and trees. Placing your nestboxes out in the open, with only a few trees, will attract bluebirds, and be less attractive to house wrens.
JAYS & CROWS can poke their heads into nestboxes and snatch eggs or nestlings. Using a box design with 7 to 8 inches from the bottom of the entry hole to the floor of the box will help keep young out of reach. If the wood of the box is very smooth, it is a good idea to cut grooves into the wood below the inside entrance hole to help nestlings get a foothold as they attempt to fledge.
BIRDS OF PREY such as the Sharp-Shinned and Cooper's Hawks, and American Kestrels have been observed preying on adult, fledgling and juvenile bluebirds. Having nearby dense cover is the bluebirds' best refuge. Avoid placing nestboxes near bird feeders or on tall utility poles where hawks often perch.
Climbing Predators
OPOSSUM, RACCOONS & CATS can be deterred by mounting the box on a pole and adding a stovepipe baffle, or place a 4-foot length of 4-inch diameter PVC pipe (that wobbles) on the pole to keep predators from climbing to the box. Make sure and put a cap on the top of the PVC pipe to prevent bluebirds from entering it. If cats are the only problem, a hanging nestbox works very well when hung 6' high and out on a narrow sturdy tree branch.