Few things are more heartbreaking than finding a bluebird nest destroyed by house sparrows. If you’ve put up nest boxes hoping to attract these gentle native birds, only to see aggressive sparrows take over, you’re not alone.

The good news? With a few strategic changes, you can protect your bluebirds and give them a safe place to raise their young.

Why House Sparrows Push Out Bluebirds

House Sparrows engage in behaviors that displace native species from the areas where they live. For example, they will take over birdfeeders and nesting boxes, driving out other birds like Eastern Bluebirds.

This makes them unpopular with naturalists and some birders. Unlike most native sparrows, house sparrows are sedentary birds that don’t migrate.

This causes problems for local bird species because house sparrows often dominate the nesting grounds that would have otherwise been used by native birds. House Sparrows are an invasive species.

You can find them everywhere, even at amusement parks competing with native birds for everything. They’ll fight other birds over food and nests.

More often than not, they’ll win.

Choose the Right Nest Box Design

Bluebirds typically nest in cavities that are 1-1/2 inches in diameter, so make sure the entrance hole on the birdhouse is this size. If it’s too small, other birds may try to take over the house, and if it’s too big, predators could get inside.

No, bluebirds do not require a perch on their nest box. In fact, perches can actually be dangerous, as they can give predators a place to perch while they reach into the box to steal eggs or young birds.

Location – The first thing you’ll need to do is choose the location for your nesting box. Bluebirds prefer open areas with little or no vegetation, so avoid placing the box near trees, bushes, or tall grass.

You’ll also want to ensure the box is placed in an area where it will get plenty of sun during the day.

Monitor and Remove Sparrow Nests Quickly

Here’s the truth about managing house sparrows: you need to check your boxes regularly. Passive monitoring won’t cut it.

Plan to inspect your nest boxes at least twice a week during nesting season—more often if you’re dealing with persistent sparrows.

House sparrow nests are easy to identify. They’re messy, bulky constructions made mostly of dried grasses, feathers, and often bits of trash like string or paper.

Unlike the tidy, cup-shaped nests bluebirds build with fine grasses and pine needles, sparrow nests fill the entire box with loose material and have a domed or rounded appearance. If you spot one starting to form, remove it immediately.

Don’t hesitate—house sparrows are not protected under the Migratory Bird Treaty Act because they’re an invasive species. You’re legally allowed to remove their nests, eggs, and even the birds themselves if necessary.

Toss out any nesting material you find, and if eggs are present, remove those too. The key is consistency.

If sparrows keep finding their nests destroyed, they’ll often move on to find an easier location.

Keep boxes empty between removals. An empty box is less appealing to sparrows trying to rebuild than one with even partial nesting material.

Some bluebird landlords check boxes daily when sparrows are particularly persistent, and that vigilance pays off. Once bluebirds claim a box and start laying eggs, your monitoring becomes even more critical—but you’ll also have more options for deterrents.

Use Simple Deterrents Like Fishing Line and Spookers

Sometimes the simplest solutions work best. Two of the most effective house sparrow deterrents require nothing more than fishing line or a few household materials, and they won’t bother your bluebirds at all.

The fishing line method is surprisingly effective. Attach monofilament fishing line (about 10-12 pound test) across the roof of your nest box in a crisscross pattern, or dangle short lengths from the roof overhang so they hang just in front of the entrance hole.

House sparrows are wary of anything touching their backs or wings as they enter, and these nearly invisible lines make them uncomfortable. Bluebirds, on the other hand, seem unbothered and slip right past.

You can also try the “Van Ert” trap design, which uses fishing line in a specific configuration to catch sparrows while leaving bluebirds alone—though this requires more setup.

Sparrow spookers are even more dramatic. Wait until your bluebirds have laid at least one egg—this is important, because spookers can sometimes deter bluebirds if installed too early.

Once eggs are present, bluebirds are committed and won’t abandon the nest. At that point, you can add a sparrow spooker: a device that sits on top of the box with long arms extending outward, decorated with metallic Mylar tape or reflective streamers that flutter in the wind.

House sparrows are deeply suspicious of the movement and flash, while nesting bluebirds quickly learn to ignore it. The shimmering, unpredictable motion is enough to keep sparrows from entering the box to attack eggs or nestlings.

You can build a simple spooker from a wire coat hanger, zip ties, and Mylar party streamers for just a few dollars. Install it as soon as you confirm bluebird eggs, and leave it up until the babies fledge.

Both methods work because they exploit house sparrows’ cautious nature around unfamiliar movement or texture. They’re not foolproof, but combined with regular monitoring, they significantly reduce the risk of attack.

Set Up a Dummy Box Trap

If you’re dealing with a particularly stubborn pair of house sparrows, a decoy box can work wonders. The concept is simple: give the sparrows what they think they want, somewhere away from your bluebird boxes.

Place a dummy box—also called a “sparrow trap box”—at least 50 to 100 feet away from your active bluebird boxes, ideally closer to buildings or structures where sparrows naturally congregate. This box should look appealing to sparrows: mount it on a pole or fence near human activity, use a standard 1.5-inch entrance hole, and let the sparrows discover it.

Here’s where monitoring becomes essential. Check the dummy box frequently.

If sparrows start building, you have a choice: you can continuously remove the nest to frustrate them, or you can use the box as a trap. Sparrow traps (which fit inside nest boxes) are legal and humane when checked regularly, and they allow you to remove house sparrows from the area entirely.

This is the most effective long-term solution if you have repeat offenders.

The key is never to ignore a dummy box. If you let sparrows successfully nest in it, you’ve just created more sparrows for next season.

Used correctly, though, a decoy box draws attention away from your bluebird houses and gives you a centralized place to manage the problem. Some bluebird trail operators use multiple dummy boxes to create a “sparrow sink” that protects dozens of bluebird boxes across a property.

Adjust Feeders to Favor Bluebirds

You can also buy one specific seed in order to attract your favorite birds and skip other types of food. For example, if you only want to feed a pair of bluebirds that you know lives in your backyard, you can buy mealworms and stick to them.

Many birds won’t care for them, but you can still enjoy those bluebirds at your feeder while saving a few bucks. Mealworms are the most common food provided to bluebirds at backyard feeders, but they have also been known to eat suet.

It’s also not impossible to see bluebirds at a traditional seed bird feeder if feeding conditions have been poor, but it’s unlikely. House sparrows visit backyard feeders, usually feeding on sunflower seeds, millet, and corn.

The birds also feed on seeds, livestock feed, and discarded food. In summer, House sparrows feed on insects and feed them to their young.

Make Your Yard Bluebird-Friendly

If you don’t already have bluebirds in your yard regularly, but you’re hoping to attract them, place the feeder out in the open where bluebirds can easily see it. There’s no guarantee that you’ll attract a backyard full of bluebirds, but it’ll give you the best possible chance.

Avoid using pesticides – Pesticides can kill the insects that bluebirds rely on for food, so it’s best to avoid using them in your yard. If you must use them, be sure to apply them only to the areas that are affected and not to the entire yard.

Pesticides are also linked to lowered rates of reproduction in bluebirds. Bluebirds nest in cavities, so you’ll need some trees that can provide nesting opportunities.

Bluebirds don’t create their own nest cavities, instead relying on decaying trees or holes made by other animals, such as woodpeckers. That dead tree in your backyard may not be the prettiest, but if a bluebird is using it, make sure you don’t remove it if you want to keep the bluebirds around.

Bluebird box and feeder checklist

Spec	What our writers say
Entrance hole	1-1/2 inches
Perch	None; a perch helps predators reach in
Box site	Open ground, little vegetation, plenty of sun
House sparrow habit	Sedentary; they stay and take boxes year-round
Bluebird food	Mealworms first; suet sometimes; seed only if food is scarce
Sparrow food	Sunflower, millet, and corn
Feeder site	Out in the open where bluebirds can see it
Pesticides	Kill the insects bluebirds eat and are linked to lower reproduction
Natural nest	Decaying trees or old woodpecker holes; leave a used snag

Keep reading

• How to Attract Bluebirds to Your Yard
• How Big Should a Nest Box Hole Be?
• How to Attract Bluebirds to Your Backyard – No Big Field Required