Beautiful and beneficial, bluebirds were once common over most of North America.
Bluebirds are beneficial in the landscape in that they eat grasshoppers and cutworms that devour garden plants.
Bluebirds have become a relatively rare sight due to pesticides, predators, and loss of habitat.
But you can encourage the return of bluebirds by giving them a place to nest.
Build a Bluebird Nesting Box
Bluebirds lied to nest in cavities in trees, but their bills aren’t strong enough for them to do their own excavating.
Bluebirds depend on abandoned woodpecker nests or decaying trees that are left alone to form natural cavities or nesting boxes built by humans.
Wrens, starlings, and sparrows are fierce competitors for these nesting sites.
You can even the odds for bluebirds by building a bluebird-friendly nesting box.
Bluebirds have some very specific size requirements for their nesting space.
Bluebird nesting box dimensions
Bluebird houses need to be a bit larger than the nesting boxes you might build for smaller birds. Every bluebird nesting box needs at least 5 inches by 5 inches (125 mm by 125 mm) in floor space.
The box needs to be at least 8 inches (200 mm) and preferably 12 inches (300 mm) tall.
There should be an entry hole with a diameter of 1-½ inches (38 mm). Place the entry hole 6 to 10 inches (150 to 250 mm) above the floor.
You may want to add an observation door so you can observe the hatchlings in their nest without disturbing them.
Make sure it has sturdy hinges and a latch so it won’t pop open, exposing the birds.
Bluebird nesting box materials
Once bluebirds find a mate and find a suitable place to nest, they raise large families. Bluebirds raise two to four broods of two to eight young every year.
You will need to provide them with a home-made of durable materials, like cedar, to keep them stable in any kind of weather.
Durable nesting boxes ensure that bluebirds will come back every year.
Male bluebirds attract their mates by displaying nesting materials next to a suitable nesting location in early spring.
By providing a nesting box and nesting materials, you are helping some male bluebirds get lucky in love.
How to mount your bluebird nesting box
You can mount bluebird nesting boxes on fence posts, on poles (check with your power company before putting on a power pole), and in trees.
You can use existing fence posts or go to your home supply center to get new posts for your bluebirds.
Here are some things to think about before you put up your nesting box:
- Be sure you sink any new posts deep enough into the ground that they don’t tip over in the wind or when someone or something runs into them.
- Place bluebird nesting boxes in trees as a last resort. Eggs and young birds in birdhouses in trees may be vulnerable to cats, squirrels, raccoons, and snakes.
- The bottom of the nesting box should be at least 3 feet (about a meter) and preferably 4 to 5 feet (125 to 150 cm) up. Place flashing or baffles (like a squirrel baffle) to deter climbing predators.
- Don’t set out bluebird nesting boxes anywhere you frequently see snakes.
- Face the box so it doesn’t catch the prevailing winds. Avoid facing the box toward the afternoon sun. In most of North America, this means the entry hole needs to be on the east side of the box.
- Whenever possible, mount the box so the entry port faces another post or pole where the bluebird can perch safely. Bluebirds like to make sure it’s safe to enter their nests before they fly in. In most situations, this means you need to provide a safety perch to the east of the entry of the box.
- If you are putting up your nesting boxes on a farm, make sure they are mounted in places where livestock can’t get to them.
Where to place your bluebird nesting box
Bluebirds catch insects in open, grassy areas.
They have good hunting whenever the grass is cut, making insects easier to find.
If you gather up grass clippings for compost, waiting a day for them to be drier and easier to handle also gives bluebirds a chance for a feast.
Bluebirds look for insects to eat from a perch, not by flying overhead like a hawk or a crow. They need shrubs or bushes or fencing around a grassy area so they search for insects from safety.
These birds don’t like foraging for insects in the middle of a large grassy field. But up to 100 feet (30 meters) of open space between perches is fine.
Good areas for bluebird nesting boxes include large lawns, small fields, fence rows, orchards where no pesticides are used, public parks, golf courses, cemeteries, and highway right of way that is kept mowed but not sprayed.
It’s also important to keep bluebirds separated from their competition:
- Bluebird boxes need to be at least 100 feet (30 meters) away from brush or woodland where wrens are common.
- Bluebirds need to nest at least ¼ mile (400 meters) from barnyards where sparrows congregate.
- Don’t expect more than one pair of bluebirds to nest in your yard. If you have swallows in your yard, then put out one box for the bluejays and another for the swallows.
When to put up your bluebird nesting box
The motto for attracting bluebirds to your landscape with nesting boxes is “Be prepared.”
If you live in the southern half of the United States or in coastal British Columbia, it’s best to have bluebird nesting boxes up by the end of February.
In colder climates, it’s OK to wait until April.
If you are ambitious about attracting bluebirds, build a bluebird trail.
A bluebird trail is a series of nesting boxes and safety perches set about 100 yards (more or less 100 meters) apart over a long stretch of continuous grasslands, such as a field, a golf course, or a meadow.
There are bluebird trails that consist of hundreds of boxes — but even one box will help.
Providing bluebirds with a place to nest is the most important thing you can do to attract bluebirds to your yard, but it’s not the only thing.
Here are some other suggestions for attracting bluebirds.
Provide nesting materials
Once you have provided a nesting site, you can also provide nesting materials. Bluebirds in nature build their nests with soft grasses and fresh, scented pine needles.
You can leave out stips of cloth and cotton balls. If you can, place the nesting box next to a stand of conifers (pines, spruce, and so on) to make it nesting-friendly.
Install a hunting perch
Bluebirds scan the grasses around them for insects. When they spot a tasty treat, then they swoop down and grab it.
They do their hunting from perches rather than spending energy flying back and forth, exposing them to their own overhead predators.
Maintaining trees and shrubs next to grass you occasionally mow (disturbing insects so bluebirds can find them faster) helps bluebirds stay fed.
For larger areas of mown grass, install hunting perches.
Wire fences make great hunting perches, as long as they are 3 to 4 feet above the ground. Any kind of pole with a cross-bar on top (making a T) also works.
Old-timey clotheslines doubled as bluebird hunting perches, or you may put up a post with a horizontal perch on top of your own.
Lawn ornaments with enough space for the bluebird to perch will also make serviceable bluebird hunting perches.
Offer live mealworms on a platform feeder
Bluebirds thrive on live mealworms. They add extra protein to the diet of growing chicks.
You can set out live mealworms on a platform feeder or in a dish in a safe location (no cats!) where bluebirds can find them.
If you don’t use a platform feeder, you will need a dish with a rim to keep the mealworms from escaping.
The feeding area needs to be at least 20 feet (6 meters) away from the nest so it does not attract predators.
Mealworms are more nutritious if they are properly maintained before they are fed to your birds.
Place mealworms in a two- to five gallons (10 to 20 liter) bucket you cover with a screen or a perforated lid.
Feed the mealworms a few slices of apple or a little cereal to keep them active until they are fed to the birds.
Keeping the mealworms in a cool location ensures they stay in the larval stage that bluebirds prefer.
You can add a few berries or a little shredded suet to the mealworms you provide your bluebirds. Elderberry, holly, and sumac (whole berries, not the powdered variety) are bluebird favorites.
Use platform feeders specifically designed for bluebirds
The platform feeders that bluebirds prefer to look like a birdhouse with clear plastic walls.
Bluebirds will be able to see the food inside and will know they are not coming in on another pair of mating birds or a predator.
The entry holes should be at least 6 inches (15 cm) above the floor of the feeder. Bluebirds find the color blue (a blue roof, for example) attractive.
When you are choosing a feeder, make sure it can be filled with live mealworms. Bluebirds won’t be able to resist them.
Add a birdbath, preferably a heated birdbath
Bluebirds need water to maintain their feathers. They are attracted to the sound of moving water, and in winter they favor warm water.
You can provide all of the water features bluebirds are looking for in a birdbath in your yard. Install a small dripper or fountain to provide the sound of moving water.
Add a heater to entice bluebirds to stay in your yard after mating season is over.
Bluebirds are intensely territorial when they are nesting, but they are very social the rest of the year.
If you install a heated birdbath, you may attract dozens of winter visitors.
Ornithologists have discovered that dehydration is a major factor in falling ill to parasitic infections in bluebirds. Birdbaths help keep bluebirds healthier.
Play a recorded bluebird song, in early spring
Bluebirds will check out any location where they hear other bluebirds, especially just before mating season.
Playing a recorded bluebird song several times a day in early spring lure bluebirds to your yard.
But you don’t want to do this too often. Female bluebirds sing and chirp in response to the recorded bluebird song. You don’t want them advertising their position to their predators.
Also, you don’t want to distract bluebirds from caring for their babies, getting food, and guarding their nest during nesting season,
Limit performances of bluebird songs to early spring.
Maintain natural cover, but not a lot of it
Bluebirds do their hunting in open grassland. They aren’t naturally drawn to dense forest or thorny thickets.
But bluebirds do recognize the need to be able to retreat to cover when predators are overhead. That’s why they like a few, solitary, mature trees in the grasslands where they feed.
Leave at least a few trees and shrubs to make sure bluebirds feel comfortable feeding on your lawn. If you don’t have trees, then plant a few berry bushes.
Plant berry bushes so bluebirds have a constant food supply
Bluebirds prefer to eat bugs, but they will supplement their diet with berries. The trees and shrubs that produce these berries also provide emergency cover.
What kinds of berries do bluebirds eat? Consider planting these species:
- Hackberry. (In Southern climates, this tree can become invasive.)
- Red cedar.
- Virginia creeper.
Mow your grass regularly
The ideal habitat for bluebirds includes mowed grasses. Occasionally disturbed grasses to release insects make hunting easier.
You need to have a yard you keep trim. Tall grasses attract other competing birds and can conceal predators.
You also need to give your bluebirds room to hunt without feeling threatened.
It’s fine to set up lawn chairs at the edges of your yard so you can watch your bluebirds, but keep a large area of your lawn uncluttered for maximum bluebird activity.
And need we mention that you shouldn’t put out pesticides that kill grasshoppers and grubs in the area where you want to attract bluebirds?
Keep Kitty indoors. Let Fido play somewhere else
Cats are natural predators of bluebirds. Dogs aren’t, but bluebirds aren’t going to take the chance to hunt in your yard while your dog is there.
It’s important to keep cats, dogs, and songbirds separated. Don’t give bluebirds any reason to doubt the safety of your landscape.
Some additional information about attracting different species of bluebirds
There are differences between Eastern, Western, and Mountain bluebirds.
These three kinds of bluebirds are actually different species, and there are subtle differences in what you need to do to make them feel at home.
Eastern Bluebirds (Sialia sialis)
If you live anywhere east of the Rocky Mountains in Canada, the United States, Mexico, or Central America, chances are any bluebird you see is an Eastern bluebird,
These bluebirds are common in the woods-growing back after forest fires. They hang out around beaver ponds. They like golf courses.
Eastern bluebirds prefer to eat bugs and worms.
They feed primarily on crickets, grasshoppers, katydids, and beetles. They will also eat earthworms, sowbugs, spiders, millipedes, centipedes, and snails.
If you want Eastern bluebirds in your yard all year round, feed them mealworms and provide a heated birdbath. Protect them from cats and snakes.
Western Bluebirds (Sialia mexicana)
Western bluebirds are concentrated in California, Arizona, and the western half of Mexico. The males have intensely blue feathers on their backs.
The females have orange breasts.
Western bluebirds pounce down on the ground after they catch insects in midair. Providing adequate space for landing is essential for keeping the birds around.
This means keeping your lawn uncluttered.
More than other species of bluebirds, Western bluebirds like berries, especially in the winter.
They also eat fallen fruit. You can keep them in your yard if you provide mealworms all year round. Dead mealworms, however, can incubate Clostridium bacteria that kill Western bluebirds.
Mountain Bluebirds (Sialia currucoides)
You will encounter Mountain bluebirds in the summer in southeastern Alaska, British Columbia, southern Alberta, and Saskatchewan, Montana, and Utah.
They will fly south for the winter but come back to the same nesting box next year to raise two more broods of young.
If you want to host these birds in the summer, provide them with a regularly mowed grassy habitat for bug catching.
If you want to host them in the winter in Texas or New Mexico, provide them with fruit and berries. But Mountain bluebirds are attracted to mealworms fed from platform feeders any time of year.
Scientists have discovered that at any time of year, Mountain bluebirds will prefer quiet habitats over noisy places.
However, they are especially attracted by playing record bluebird songs in the early spring.
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