Discover the Secret Recipe to Bring Bluebirds to Your Yard – It’s All Down to the Right Plants, Food, Shelter and Water
Back from the brink after huge population decline, there is still much homeowners can do to encourage these beautiful birds
Although a year-round native in many parts of the US, the beautiful bluebird and its soothing song, signals spring for much of the north. With its eye-catching plumage and associations with hope and happiness, there are multiple reasons you would want to attract these enchanting birds to your yard.
Wherever you live, with three different bluebird species: eastern (Sialia sialis), western (Sialia mexicana) and mountain (Sialia currucoides), there are similar practices that will lure these charming creatures and support their survival.
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Bluebirds in the US
'Bluebirds are fairly easy to find these days in terms of range and abundance, but they are just uncommon enough that it’s a treat when you spot one,' says Holly Grant, Project Assistant, Nest Watch, Cornell Lab of Ornithology.
'That semi-scarcity aids in their attractiveness, but also, there’s a value afforded them because of the population declines they experienced in the early 1900s.'
Eastern Bluebirds in particular were affected due to habitat loss and fierce competition with European Starlings and House Sparrows for nesting space.
'There was a big push in the 1960s and 70s for installing nest boxes that exclude starlings,' says Holly. 'These nest-box campaigns alleviated much of the competition and allowed bluebird populations to recover.'
Holly Grant is Project Assistant of Nest Watch at Cornell Lab of Ornithology, where she keeps Nest Watch running smoothly. She is passionate about wildlife conservation and has a B.S. in Conservation Biology, SUNY College of Environmental Science and Forestry. Some of Holly's best learning experience have been during fieldwork. She is now able to facilitate the same kind of hands-on learning experiences with people of all ages through participatory science projects.
1. Install a Bluebird Nest Box
Aside from the sheer pleasure of seeing our feathered friends, birds benefit your backyard in multiple ways, so it's always worth attracting them. Bluebirds nest in tree cavities made by larger birds, like woodpeckers. So a nest box is one of the biggest draws for these colorful creatures.
Habitat loss and competition from non-native species (those European Starlings and House Sparrows), makes these cavities scarce, which is why the nest box campaign has been so successful.
This birdhouse from Ace Hardware is especially attractive to eastern bluebirds, due to the shape and size of the entrance.
'Bluebirds are a secondary cavity nester, which means they need an existing tree cavity to nest in,' explains Alexandra Wardwell, Prairie Project Manager with the National Audubon Society. 'They cannot excavate cavities on their own, so they often rely on other birds like woodpeckers.
'Nest boxes are a great way to attract bluebirds to an outdoor space. It’s very important that the bluebird box hole is the right size (about 1.5 inches for Eastern Bluebirds and slightly bigger 19/16 inches for Western Bluebirds) to help deter larger non-native species like House Sparrows or European Starlings.
'Adding a metal entrance hole protector can prevent squirrels from enlarging the opening. Remember to clean nest boxes between broods or before the next nesting season.'
Alexandra Wardwell manages Audubon’s prairie and wetlands restoration and enhancement program in western Minnesota within the globally unique Tallgrass Aspen Parklands region. She lives in northwestern Minnesota with her family where she gardens with native plants and enjoys living close to thousands of acres of public wildlands.
2. Make Nest Boxes Safe and Secure
The best birdhouse for bluebirds is one that competing species and predators can't access. So it's important to choose (or make) one that will keep bluebirds out of harm's way and provide a comfortable home. This can vary according to your region.
'There is no one-best design for a bluebird nest box, and this is mainly because their habitat and threats differ geographically and locally,' explains Holly.
'The nest box plans on the Cornell Nest Watch website include a tall oval-like entrance hole, which has been shown to deter House Sparrows. This would be a good design to use in a space where House Sparrows are common.
'However, if House Sparrows aren’t common in your area, you might instead stick to the standard 1.5” round entrance hole.'
Ornithology organisations, such as Cornell and Audubon, recommend using untreated, unpainted wood for birdboxes, but there are different features that can be helpful too. Audubon also offer advice on how to build a bluebird nest box.
'A slanted roof to facilitate rain runoff and drainage holes are important if you live in a spot that gets heavy rainstorms,' says Holly. 'Ventilation holes are good for boxes placed in areas that get particularly hot in summer.
'Cone baffles, stovepipe baffles, noel guards, and entrance hole extenders/restrictors are all great ways to help ward off predators and/or competing invasive species from accessing the contents inside the box and disrupting the progress of the nest.'
This hanging baffle from Ace Hardware can prevent squirrels, racoons and other predators from accessing a nest box.
3. Put Nesting Boxes in the Best Location
To give these beautiful birds the best chance, it's important to avoid bird box mistakes. The timing and location of your nest box installation can determine whether bluebirds take to it straight away, or wait until the next breeding season to move in. Cornell recommend putting nest boxes up in the fall, well before the start of the following breeding season.
'Not only is the ground easier to dig into, this gives the birds time to get used to the boxes in their environment, and investigate once they're ready to look for nesting space,' says Holly. 'Plus, bluebirds will sometimes use nest boxes as roosting space in the winter.
However, Holly emphasises that it is fine to put next boxes up in spring and summer too. 'If there is a dearth of natural cavities, or there’s lots of competition for nesting space, the birds will be more desperate for any cavity space they can find,' she says.
Made from cedar, this birdhouse from Ace Hardware has all the attributes to make a comfortable home for bluebirds.
If you want to put up a nest box in spring, Nest Watch offers instructions on how to install them on a pole. Mounting nest boxes on a free-standing pole, so that baffle predator guards can be used, is a good way to keep the birds and any subsequent eggs safe.
The nesting season also varies slightly across the bluebird species: 'For the Eastern bluebird it's as early as late February in southern gulf states, but certainly by mid-March over most of their range,' says Holly.
'The Mountain bluebird nests around early April and Western Bluebirds around mid-April in some more temperate areas, but certainly by early May over most of their range.
'Sometimes bluebirds will take to a box immediately, and sometimes it may take until the following spring for them to actually find and use one you’ve installed,' says Holly.
4. Grow their Favorite Plants and Trees
During spring and summer, bluebirds love to feed on bugs, before switching to berries in the fall. Growing the native plants and trees that attract or produce their favorites to feast on will ensure these feathered foragers are regular visitors to your yard.
'Bluebirds prefer forest edges or open lands with scattered trees or shrubs for perches,' says Alexandra. 'They also rely heavily on caterpillars during the nesting season. Native trees like oaks, hickories, maples, and plants in the Prunus genus (cherries or plums) are hosts to many butterflies and moths.'
'Insects are critical for most songbirds during the nesting season, including bluebirds,' adds Holly. 'Bluebirds feed their young mainly insects while in the nest. Those proteins are a major part of what helps the chicks grow strongly and quickly.'
Bluebirds shift to fruits and berries as the insects become less available. Native plants that both encourage the insects – and produce the fruits – that these birds love to eat creates a sustained supply across the seasons.
'Eastern bluebirds feed on caterpillars, beetles, crickets, grasshoppers, and spiders,' says Holly. 'In fall and winter, they eat large amounts of fruit including mistletoe, sumac, blueberries, black cherry, tupelo, currants, wild holly, dogwood berries, hackberries, honeysuckle, bay, pokeweed, and juniper berries.
This white flowering dogwood tree from Fast Growing Trees is native to the eastern US, hardy in zones 5-9 and attracts the pollinators bluebirds feed on.
Mountain bluebirds eat similar bugs, but in winter will eat small fruits and seeds too. 'These include grapes, currants, elderberries, cedar berries, and the seeds of sumac, mistletoe, and hackberry,' says Holly.
Growing this Adams elderberry from Nature Hills would provide ample fruit for bluebirds.
It's a similar diet for Western Bluebirds, who will prey on ants, wasps, pillbugs and snails, as well as grasshoppers, caterpillars and beetles. 'They will also eat many kinds of berries when there are no insects,' says Holly. 'Particularly elderberry, grapes, mistletoe, raspberries and blackberries, serviceberry, sumac, chokecherries, juniper, and poison oak.'
This gorgeous Sumac Tiger Eyes cutleaf from Nature Hills would suit a sunny spot or rock garden and is hardy in USDA Hardiness zones 4-8. It not only produces the berries bluebirds love, it's a spring to fall showstopper too.
5. Add a Bird Bath or Fountain
Bluebirds need to keep their spectacular plumage clean; they also need fresh water to drink, so a bird bath is a good strategy if you'd like to see more of these attractive feathered fellows.
This solar bird bath fountain from Amazon will keep visiting bluebirds very happy, while, not costing you a dime to run.
'Dripping or moving water is very attractive to all birds and a great way to get bluebirds to notice your yard,' says Alexandra. 'There are commercial drippers available, but you can also create your own by securely suspending a metal or food safe plastic container over the birdbath, making a small hole in the bottom of the container, and filling it with water.
'Bird baths should be shallow (1-2 inches deep), elevated off the ground, and located near trees or shrubs that provide perching and cover. If a bath is too deep, add clean stones to create shallower areas. It’s important to clean bird baths regularly to prevent disease.'
'Change the water every day to keep it fresh and clean, especially during the summer,' adds Holly.
This green resin bird bath with a solar fountain from Lowe's offers the moving water bluebirds love.
6. Hang a Feeder
Hanging feeders are not quite the magnet for bluebirds, that they are to other species – unless their natural food sources are scarce. If you don't have the space to grow the shrubs and trees suggested, a hanging feeder can be helpful to these pretty cerulean songsters, but be sure to fill it with the best food for bluebirds.
'In addition to insects and native fruits, bluebirds may sometimes be attracted to supplemental foods like mealworms, shelled sunflower seeds, and suet nuggets,' says Alexandra.
This hanging bluebird feeder from Lowe's has a squirrel guard and can be filled and cleaned easily.
Although bluebirds numbers have increased to healthier levels, changing weather patterns are still a threat, and encouraging these charming birds to your yard will help to sustain them. It's also a delightful activity for you and your family, especially younger generations.
'Providing habitat for bluebirds is a great way to connect with nature,' says Alexandra. 'I especially love the impact that watching a nest box has on children as they watch all the steps it takes from building the nest to the young fledging.
'My grandma was an avid Eastern Bluebird box caretaker in Wisconsin, and tagging along with her to clean and check boxes really had an impact on me.'
If you want to take your conservation efforts one step further, consider joining NestWatch. The general advice to stay away from nests is different with bluebirds. 'NestWatch participants visit bluebird nests about once or twice per week and report what they see – species, how many eggs, when they hatch, when they fledge, etc,' explains Holly.
'Once they submit that data to our website, it joins hundreds of thousands of other anonymized records that are made available to researchers, who help us monitor the nesting success of these birds. It’s free and we offer a short easy training to help participants learn how to keep birds safe during monitoring.'
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