A Bit About Bluebirds
There are entire websites devoted to the care of bluebirds, so we'll just get you started with the basics here. We have links at the bottom for much more detailed information and instructions on housing, feeding, and protecting the bluebirds in your care.
North America is the native home to three species of these graceful and uniquely colorful thrushes: Eastern, Western, and Mountain Bluebirds. Similar in many ways, all three are a delight to observe in their natural habitat of mostly-open countryside. Bluebirds eat primarily insects and berries, and are frequently seen perching on fence posts or branches, ready to dart down for a cricket or caterpillar.
In recent decades, native bluebirds have seen their numbers drop steeply due to competition and aggression from invasive non-native birds, particularly European Starlings and House Sparrows. Bird enthusiasts all over the United States have been working to re-establish their population by installing bluebird nest box trails and committing to monitoring them year after year.
How You Can Help Bluebirds with Nest Boxes
Housing and protecting the nests of bluebirds is a commitment that should not be taken lightly. During breeding season, aggressive House Sparrows are quick to take over a bluebird nest, killing nestlings and sometimes trapping and killing the parent as well. House wrens and tree swallows are happy to take over a nest as well, though at least tree swallows are less violent about it. It's important during nesting season to check the nest boxes frequently and remove nests of other birds before they lay their own eggs. Some preventative measures should be taken to help prevent bluebird deaths.
- Mount the nest box on a metal pole with a baffle. This is extremely important! Mounting on a tree or fence post will allow predators such as snakes, raccoons, and cats easy access to eggs and birds. A metal pole with grease will keep ants out, and a long baffle placed up near the bottom of the house will stop climbing predators. A predator guard or copper portal can also be added to help keep larger birds from enlarging the opening.
- Place nest box at least 100 ft from tree line or shrubs. House wrens are less likely to venture that far from cover. Add a house wren nest box with a 1" opening near shrubbery. House wrens are protected as a native species, so if you find a nest with wren eggs in your bluebird house, it must be left alone.
- If tree swallows are interested in your bluebird house, a good solution is to add a second bluebird nest box 15-25 feet away. Tree swallows are beneficial to bluebirds as they will help defend the nests against wrens, sparrows, and other swallows. Bluebirds and tree swallows don't mind being neighbors.
- Nest boxes should be opened once or twice a week during nesting season to ensure a house sparrow has not taken over. Stop once the nestlings are 12-14 days old to prevent premature fledging. You'll need to learn what each bird's nest and eggs look like to ensure you're not removing eggs and nests of native species, as they are protected by law. House sparrows are not native and not protected by law. An informational sheet with illustrations of the different nest types is included with every bluebird nest box we ship to you.
- Avoid anything that attracts house sparrows. Bluebird nest boxes should not be placed anywhere near buildings or sources of sparrow food. Don't use bird food that includes milo, millet, or cracked corn at your bird feeders.
A single bluebird nest box that is left to house sparrows will result in up to 20 more (aggressive) house sparrows every year. If you're unable to monitor your nest box, it would be far better to take it down or block the entrance for a season than allow it to be used by house sparrows!
Can I Feed My Bluebirds?
Definitely! Bluebirds primarily eat insects, and supplement their diet with berries (especially in the winter). They don't need a feeder, but offering live mealworms (actually the larvae of a beetle) is helpful in attracting bluebirds to your nest site, providing easy nutrition for tired parents, and when food is scarce during the winter. It's also a fantastic way to see these beautiful birds up close!
A good rule of thumb is to offer ~15 worms per day per bird. They're not a complete source of nutrition so it's good for bluebirds to not depend on mealworms for the majority of their diet. Many other birds (tufted titmice, robins, jays, orioles, Carolina wrens, nuthatches, and chickadees, etc) love mealworms too, so if you end up with an excess supply you can make a lot of other birds really happy.
Bluebirds naturally eat from the ground, but if you don't want robins eating everything you'll need to offer the mealworms in a feeder. Platform and cup feeders are ideal. Our hanging bluebird feeder is an enclosed platform feeder with 1-1/2" openings on the ends and viewing windows on the side, which offers bluebirds protection from larger birds. Cup feeders are another great option, and are great for feeding bluebirds, as well as orioles, cardinals, and woodpeckers! (Please note: A bluebird feeder should be placed at least 100 feet from any bluebird nest boxes so as to not draw unwanted attention of predators or competitors for the nest box.)
What Else Should I Know?
There is so much more information out there! The above information is just a quick-start guide. We recommend checking out the North American Bluebird Society's website for the official guides on nest boxes, bluebird trails, and how to deal with predators and pests. We also recommend sialis.org as an extremely thorough source of everything you'd ever need/want to know about bluebirds!