While some birds build nests on tree branches, shrubs, porches, and gutters, others seek an enclosure of sorts. These "cavity nesters" look for—or, in the case of woodpeckers, create—holes in wood to build nests and lay eggs. Unfortunately, there aren't enough holes to go around.
That's where birdhouses (also known as nest boxes) come in. They provide valuable homes for many species of birds and a wonderful opportunity for birdwatchers to enjoy viewing the age-old process of breeding. Here’s what you need to know about birdhouses!
Species That Use Birdhouses
Different birds have different needs when it comes to nest boxes. Download our handy chart for more details!
Among the birds that like a roof over their heads are Eastern Bluebirds, chickadees, woodpeckers, Eastern Screech-Owls, Barred Owls, wrens, and nuthatches.
Different birds prefer different sizes for the hole (or opening), as well as how high that hole is from the birdhouse floor. Be sure to consult our helpful chart to make sure you select the right birdhouse!
Important for Urban & Suburban Areas
If you live in the city or a populated suburb, you'll most likely want a hole no bigger than 1.25." That size is big enough for chickadees and wrens, but too small for House Sparrows—an invasive, non-native species that can be detrimental to bluebirds, chickadees, and other species.
Birdhouse Appearance and Style
Do any search online and you can find birdhouses in all shapes, sizes, and colors, and made of all sorts of materials. They’ve become a bit of a novelty item. But, to have the most success in attracting birds to a birdhouse, we like to keep things simple.
→ Birdhouses should be made of wood. Not only is wood durable, but it's porous enough to allow moisture and heat to escape during the summer, which keeps the young birds from getting too hot inside. Metal and plastic can get too hot, which can cause harm to the birds.
→ Please resist the urge to get creative. Birds avoid bright, unnatural colors since they are too obvious to predators. Use natural, unpainted wood instead and stain the outside with a natural wood preservative such as linseed oil.
→ Stay away from any birdhouse with a perch. Birds don't need them and they only make it easier for predators or unwanted birds to get in.
Placing a Birdhouse
The best time to put up a new birdhouse is in the fall or winter so that birds will have plenty of time to locate them before the breeding season.
What type of bird you want to attract will determine where you place a birdhouse. For example, bluebirds will use houses in open fields; chickadees, titmice, and nuthatches all like the open woods and edges; woodpeckers like forest openings and edges; and so on. For more details, download our nesting chart.
The type of bird may also determine whether you place your birdhouse on a pole or up in a tree. Nuthatches and woodpeckers prefer the latter. Regardless, always mount the house with the entrance hole facing slightly downward to keep wind and rain from entering. And make sure it's secured so that it does not swing or move.
Before you put up birdhouses all over your backyard, keep in mind that a general rule is to place no more than two houses per species per acre of property.
Fending Off Intruders
Like any house, intruders can be a big problem for baby birds. Squirrels, raccoons, snakes, cats, and House Sparrows can all cause harm to eggs and helpless baby birds. Fortunately, there are options to help keep predators at bay.
Many birdhouses now come equipped with predator guards, a metal reinforcement plate or a piece that fits around the opening. Baffles can be placed on poles to keep foes from crawling up.
- To keep House Sparrows out of Eastern Bluebird boxes specifically, keep the birdhouse lower than 5 feet.
- Tree Swallows may also occupy bluebird houses, but this can be alleviated by placing two birdhouses 10 to 12 feet apart. Tree Swallows may use one while keeping other swallows away, leaving the second box open for bluebirds.
How to Care For Birdhouses
Once breeding season is over—usually by mid-August—it's a good idea to clean out the birdhouse. Remove old nesting material and scrub the house with a solution of one part bleach to nine parts water. Rinse well and leave it open to dry completely.
For birds that have multiple broods per season, such as bluebirds, it's a good idea to clean out nesting material between broods. Keep a close watch on the birds to make sure they have completely fledged (left the nest) before attempting to clean.
To make cleaning as easy as possible, look into buying a birdhouse with one side that easily opens. Some even come with a second side the opens to a clear acrylic wall, allowing you to observe the birds without disturbing them.
Once clean, it's fine to put the birdhouse back up for the duration of the year. In fact, it may be used by some birds for night roosting, and it can provide valuable shelter during extremely cold winter nights.