Birdhouse Plans, Types, Placement and How to Build One by Species

Entrance hole sizes: matching the birdhouse to the bird

A House Sparrow can squeeze through a hole 1 1/4 inches across. A European Starling needs 1 9/16 inches. Those two figures, both from Cornell Lab NestWatch, explain most of what a birdhouse is: a box sized so that one native species can enter and the two introduced competitors cannot. Every set of bird house plans starts with the hole, and the rest of the box (depth, floor, height on the pole) follows the bird that hole admits.

The table below takes the four common backyard nesters from NestWatch’s species pages, where each figure is given for its own downloadable plan. The bluebird hole comes from NestWatch’s entrance-size chart, which matches the 1 1/2 inches in the North American Bluebird Society and New York State plans.

Species	Entrance	Inside depth	Box width x length	Height from ground	Facing
Black-capped Chickadee	1 1/8 in	8 in	5 1/2 x 5 1/2 in	5 to 15 ft	Away from prevailing wind
House Wren	1 to 1 1/8 in	8 in	5 1/2 x 5 1/2 in	5 to 10 ft	Any
Tree Swallow	1 3/8 in	9 in	5 1/2 x 5 1/2 in	5 to 6 ft	South or east
Eastern Bluebird	1 1/2 in	9 in	5 1/2 x 5 1/2 in	4 to 6 ft	East, toward open habitat

NestWatch’s own pages give the House Wren two figures: 1 inch on the species plan, 1 1/8 inches on the entrance chart. Either keeps sparrows out. The chart also covers birds that use the same kind of box at other sizes:

Entrance	Species (NestWatch entrance chart)
1 1/4 in	Tufted Titmouse, Red-breasted Nuthatch, Prothonotary Warbler
1 3/8 in	White-breasted Nuthatch, Violet-green Swallow
1 1/2 in	Bewick’s and Carolina Wren
1 9/16 in	Mountain Bluebird, Ash-throated and Great Crested Flycatcher
2 1/2 in	Northern Flicker
3 in	Eastern and Western Screech-Owl, American Kestrel

Anyone working out how to build a birdhouse for a particular bird should settle this number first. A hole one size too big is an easy mistake on a decorative birdhouse, and a costly one for the birds. At 1 1/2 inches a box is open to sparrows; at 1 9/16 it is open to starlings, which NestWatch describes as birds that destroy nests and eggs and kill nestlings and adults while taking over a site. Measure before mounting.

Artistic and architectural birdhouses

Searches for artistic bird houses, an architectural birdhouse or decorative birdhouses turn up miniature cottages, lighthouses and painted gourds. Oregon State University Extension puts the problem plainly: “There are many kinds of decorative birdhouses for sale. But they might not be right for use.” A house shaped around its looks is often meant to be displayed rather than occupied, and the nest box guidance from extension services and Cornell Lab NestWatch shows where such designs usually go wrong.

• Perches. Decorative houses often add a perch or porch. NestWatch calls a perch “unnecessary for the birds” and says it can help predators gain access to the box. The University of Nebraska-Lincoln Extension gives the same reason.
• Entrance hole. Nebraska’s guide says birds can be particular about hole size, so measurements should be fairly exact. Oregon State gives 1 1/2 inches for most songbirds. NestWatch lists a different size for each species, and a hole sized for looks fits no particular bird.
• Paint and finish. NestWatch calls for untreated, unpainted wood, and Oregon State warns that toxic fumes from treated, stained or painted lumber may harm the birds. Nebraska says not to paint the interior or the entrance hole.
• Ventilation and drainage. NestWatch specifies four 5/8 inch ventilation holes near the top of the side walls and at least four drainage holes of 3/8 to 1/2 inch in the floor.
• Cleanout. NestWatch recommends a hinged side for cleaning and monitoring. Nebraska notes that old nesting material, eggs and dead nestlings should be removed to keep parasites down, so a house that cannot be opened cannot be maintained.

Before one goes up, a short check helps:

1. Pick the bird first. NestWatch’s Right Bird, Right House tool sorts species by region and habitat.
2. Measure the hole and the interior against that species’ dimensions.
3. Look for a perch, interior paint or sealed seams, and remove or reject any that are present.
4. Confirm that the house has drainage, ventilation and a side or front that opens.

A house that fails the check can still serve as garden art, kept on a shelf or a wall. The chart of entrance hole sizes above and the parts of a good nest box below give the working dimensions.

Birdhouse types beyond the single box

Most birdhouse types share one layout: a single cavity with a hole in the front board, a sloped roof and a side or front that opens. What changes between them is scale. A chickadee box in NestWatch’s plan measures 5 1/2 by 5 1/2 inches, a flicker needs a 2 1/2 inch hole, and screech-owl and kestrel boxes take a 3 inch entrance and, at that size, non-pressure-treated exterior plywood becomes an acceptable material, according to NestWatch. Duck boxes are deep enough that NestWatch recommends a strip of 1/4 inch hardware cloth stapled inside from the floor to the hole, so ducklings can climb out.

Colonial housing is a different type altogether. Purple martins nest in groups, in multi-room houses or in strings of gourds raised on a pole, and the purple martin guide covers those houses, gourds and their poles in detail, with compartment sizes on the martin housing page. The Purple Martin Conservation Association recommends at least four cavities, and between six and twelve as a good start for a colony.

A third group uses no cavity at all. American Robins and Eastern Phoebes are listed in NestWatch’s Right Bird, Right House tool with nest structures that attach to a building. The tool sorts every species by region and habitat, with free plans, which makes it the quickest way to check what can realistically nest in a given yard.

Gourds deserve a short side note. A hollow gourd may be the oldest birdhouse type on the continent: Native Americans hung empty gourds for Purple Martins before Europeans arrived, according to the Cornell Lab’s All About Birds. Martin landlords still use natural and plastic gourds. Of all these types, the single box gives the most control over inside dimensions for small songbirds, which is why the rest of this page deals with boxes.

Two searches that look like birdhouse questions have their own pages. Hummingbirds do not use nest boxes, and the hummingbird house page explains what helps them instead. Woodpecker houses covers which woodpeckers take a box and how roost and nest boxes differ, and wood duck houses covers the large over-water box. Two makers that readers ask about, Heartwood and Lazy Hill Farm, are described on their own pages.

The parts of a good nest box: floor, roof, walls, holes

NestWatch’s checklist for a good birdhouse is short and specific, and it is the same whether the box is bought or built.

The walls should be untreated wood (cedar, pine, cypress or fir) at least 3/4 inch thick. A board sold as “1 inch” is 3/4 inch in practice, so ordinary 1x6 lumber meets the standard. Assemble with galvanized screws; nails loosen and let rain in, and staples are out.

The roof slopes and overhangs the front by 2 to 4 inches and the sides by 2 inches, which keeps driving rain off the entrance and makes it harder for a predator to reach in from above. NestWatch adds a refinement that most store boxes skip: 1/4 inch deep cuts under the roof on all three edges act as gutters.

The floor sits recessed at least 1/4 inch up from the bottom of the walls and carries at least four drainage holes of 3/8 to 1/2 inch, or the corners of the floorboard are simply cut off. The North American Bluebird Society plan recesses its floor 3/4 inch and uses the cut-corner method.

Ventilation is two 5/8 inch holes near the top of each side wall, four in total, per NestWatch. The bluebird society plan uses three 1/2 inch holes per side, drilled at an upward angle under a wide roof, and notes that in colder areas less ventilation may be needed.

Inside, the wall below the entrance should be rough, sanded coarse or cut with shallow horizontal grooves, so nestlings can climb to the hole. NestWatch singles out swallows as needing that help most. Outside, there is no perch. A hinged side with a latch lets the box be opened for monitoring and cleaning, and a few extra inches on the back board make mounting on a pole easier.

That list sounds fussy. It is also short enough to check against a store-bought box or a diy birdhouse in a few minutes.

Birdhouse placement: height, facing and spacing

Placement decides whether a well-built box gets used. The height ranges in the table above are NestWatch’s: 4 to 6 feet for an Eastern Bluebird, 5 to 6 feet for a Tree Swallow, 5 to 10 feet for a House Wren, 5 to 15 feet for a Black-capped Chickadee. The New York State Department of Environmental Conservation bluebird plan puts the base of the box about 4 to 5 feet up and prefers boxes at least 100 feet from woods or thick brush, because bluebirds hunt ground insects over short grass.

Habitat matters as much as height. NestWatch lists the Eastern Bluebird for grassland and open woodland, the Tree Swallow for grassland, lakes, marshes and shores (ideally high unmowed grass near water), the chickadee for forest, open woodland and towns, and the House Wren for forest, woodland, shrub and towns, within 100 feet of woody vegetation but with open flight space around the box.

Spacing is where the sources start to argue, and the disagreement is instructive. Bluebirds and Tree Swallows often compete for the same boxes. NestWatch suggests pairing boxes 15 to 20 feet apart, with each pair about 300 feet from the next, so that each species can take one box of a pair. The New York DEC plan suggests two boxes about 5 feet apart for the same purpose. Both aim at the same outcome, one box for each species, and the spread between 5 and 20 feet suggests that having the second box matters more than the exact distance. NestWatch’s Tree Swallow page adds a third number: if a bluebird wants a swallow’s box, put another one 20 to 25 feet away.

House Wrens need the opposite treatment. Males fill several cavities with twig “mock nests,” and both sexes may destroy the eggs or young of nearby cavity nesters, so NestWatch advises keeping boxes meant for other species at least 100 feet from a wren box, in more open habitat that wrens find less attractive.

Facing varies too: east toward open ground for bluebirds, south or east for Tree Swallows, away from the prevailing wind for chickadees, and any direction for wrens.

Predator guards and the metal pole

NestWatch’s quick checklist ends with two items that matter more than anything about the box itself: a predator guard, and a metal pole. Birdhouses are less hidden than natural nests, and some predators learn to raid them.

Snakes climb unguarded poles easily; the ones most likely to enter birdhouses are generally non-venomous species such as racers and rat snakes. Raccoons remember box locations from year to year. Chipmunks both raid nests and compete for boxes. Cats jump, so a box has to be high enough and far enough from trees that a cat cannot reach the roof in one leap. For raccoons and chipmunks NestWatch’s advice is direct: use a metal pole with a baffle and avoid trees and fence posts. An unguarded fence post is, on that evidence, the weakest common choice for a bluebird house.

Three baffle designs come up again and again. A cone baffle is a metal collar about 3 feet across under the box. A stovepipe baffle, generally 8 inches in diameter and 24 to 36 inches long, is the most complex to make and perhaps the most effective. A Noel guard is a wire-mesh tube fixed to the front of the box around the entrance, useful with another guard or on a box that has to go on a tree. The same principles scale up for purple martin poles, and the page on pole guards for martin housing deals with that larger setup.

House Sparrows and European Starlings

Both species were introduced to North America in the 19th century, live year-round near people, and readily take nest boxes. Neither is protected by the Migratory Bird Treaty Act. That legal line is the key fact for any box owner: removing a House Sparrow nest is allowed, while harming any native bird, its nest or its eggs is illegal, as NestWatch stresses at the top of its guidance.

Starlings are the easier problem. Any entrance under 1 1/2 inches keeps them out of small-bird boxes, NestWatch says. House Sparrows fit through 1 1/4 inches, so a bluebird house cannot exclude them by size, and NestWatch is candid that no completely sparrow-proof box exists.

What does work, in order of effort: place boxes away from houses, barns and farmyards, where sparrows concentrate. Avoid feeding them; millet, cracked corn and milo in cheap seed mixes draw sparrows, and the bird feeder guide covers feeding choices in more detail. Keep entrances plugged until migratory species return, because sparrows do not migrate and otherwise get first pick. Once sparrows start building, remove the material every few days, for at least a week; NestWatch notes this works best with a single backyard box, since evicted sparrows may move into a neighboring box with an active bluebird or swallow nest. Egg oiling and trapping are the active methods NestWatch describes for heavy sparrow pressure, with the condition that traps are checked hourly and the operator can identify a House Sparrow with certainty.

NestWatch’s bluebird page offers one more trick: drill a second, identical entrance beside the first, which helps bluebirds defend the box.

Bluebird house plans from one 1x6 board

The North American Bluebird Society’s 2020 Eastern Bluebird plan is the clearest of the free bluebird house plans because the whole box, apart from the roof, comes from one standard 1x6 board 4 feet long. The cuts add up exactly to 48 inches: floor, two sides, front and back laid end to end.

Part	Size (from the NABS 2020 plan)	Stock
Floor	4 x 5 1/2 in	1x6
Side (2)	5 1/2 in wide, 12 in on the long edge, 10 in on the short edge	1x6, one 22 in length split on a 70 degree cut
Front	5 1/2 x 10 in	1x6
Back	5 1/2 x 12 in	1x6
Roof	10 x 12 in	1x10
Fasteners	about 20 x 1 3/4 in galvanized nails or 1 5/8 in deck screws; 2 pivot screws or nails, 1 3/4 in; 1 double-headed (duplex) nail for the latch

The plan’s other numbers: a 1 1/2 inch entrance, or 1 9/16 inches where Western or Mountain Bluebirds are the target (that size also suits Eastern Bluebirds); three 1/2 inch ventilation holes in each side just below the roof; a floor recessed 3/4 inch with its corners cut for drainage; a roof sloping 20 degrees from back to front, overhanging the front by about 6 to 6 1/2 inches and the sides by about 2. An optional oval entrance is made by drilling two 1 3/8 inch holes one above the other and chiseling the sides flat, giving an opening 2 1/4 inches tall.

These bird house plans differ from NestWatch’s in one detail worth knowing. NestWatch lists a 5 1/2 by 5 1/2 inch box width and length for bluebirds; the bluebird society’s floor piece is 4 by 5 1/2 inches, fitted between the sides. Each plan is internally consistent, so a builder should keep one plan’s numbers together rather than mixing them.

Cedar or redwood is best for this bluebird house, the society says; exterior plywood works too, but never pressure-treated. Pine or plywood boxes should be sealed or painted a light color, white being ideal, on every face except the front with the hole.

How to build a birdhouse from the cut list

Start cutting at the floor end of the board and work toward the back piece, the plan advises, because the back’s length is the least critical and absorbs any small error. That order is the first practical lesson in how to build a birdhouse from a single board: the forgiving part goes last.

Drill the entrance and the ventilation holes before assembly, while the boards are flat. Sand the entrance smooth. On the inside of the front board, below the hole, cut a few shallow saw kerfs as a ladder for the fledglings. The NABS plan suggests drilling 3/16 inch clearance holes for the outside screws and 1/8 inch pilot holes into the inner board, so the screws do not split the wood.

Fasten the front, back and fixed side to the floor, set 3/4 inch up from the bottom edges. The second side is the door: in the plan’s drawing it hangs on two pivot screws near the top, one through the front and one through the back, so its lower edge swings out. A hole drilled through the front board and into the edge of the door takes the double-headed nail that holds it shut. Fit the roof last, with its long overhang to the front.

A DIY birdhouse built this way costs one board, a roof scrap and a handful of screws, and it covers the construction items on NestWatch’s checklist; the predator guard and the metal pole belong to the mounting. For anyone learning how to build a birdhouse, the plan has another advantage: every cut but one is square. NestWatch’s Tree Swallow figures differ from its bluebird figures in the hole (1 3/8 inches) and in height and spacing, not in depth or width, so the same box can be drilled for swallows.

A diy birdhouse for chickadees or wrens follows the same construction principles with a 1 1/8 inch hole and NestWatch’s 8 inch depth, and it goes where those birds live: closer to trees and shrubs, as the placement section above describes.

Plan sheets for the bluebird, chickadee and house wren

Three dimensioned plan sheets sit one level down. Each gives the front panel and the side section with dimension lines, a cut list that can be read in inches or millimeters, and the sources behind every figure. The eastern bluebird plan, the black-capped chickadee plan and the house wren plan are collected on the plan sheets page, which also compares the three boxes side by side. They follow NestWatch’s dimensions, so a builder using the bluebird society’s one-board plan above should keep that plan’s numbers together rather than mixing the two.

When to put a birdhouse up, and when to clean it

The best season to put up a birdhouse is fall or winter. NestWatch suggests having new boxes built and installed before the ground freezes and well before spring breeding, so birds can find them before they decide where to nest. The New York DEC asks for bluebird boxes to be mounted by mid-March. Where House Sparrows are common, mount early but keep the entrance plugged until the migrants arrive, accepting that resident chickadees, titmice and nuthatches will have to wait too.

Cleaning has a firm rule and a soft one. The firm rule, from NestWatch: clean only when there is absolutely no sign of breeding activity; if in doubt, come back another day. The soft one is timing. Some monitors clean after every brood, which NestWatch’s bluebird page encourages, because a cleaned box can host a second nesting attempt. Waiting until fall is also fine.

The research NestWatch summarizes does not give a single answer. In North Carolina, researchers who cleaned half of 100 boxes after a first brood found that 71 percent of Eastern Bluebirds moved to a clean box for the next attempt (Stanback and Dervan, 2001). A Kentucky study found the reverse, bluebirds preferring boxes with old nests, possibly because parasitic wasps there kill blowfly pupae over winter (Davis and colleagues, 1994). In Illinois, removing old nests from House Wren boxes made no real difference to mite numbers (Pacejka and Thompson, 1996), and male House Wrens clear old material between clutches on their own. Bluebirds do not; they build on top, and a box left uncleaned for years can fill until the nest sits close enough to the hole for a predator to reach.

Mice change the calculation. A box that hosted a rodent nest over winter should be cleaned in spring with a soapy solution, wearing gloves and a mask.

Checking a nest box without doing harm

A box that is never opened is a box nobody knows anything about, but checks done badly cost nests. NestWatch’s code of conduct sets the pace at a visit every 3 to 4 days, with weekly checks still worthwhile. Most successful songbird nests last about 30 days, so a season means five to ten visits per nest, each under a minute.

Timing rules out several windows. Not early morning, when most birds lay and eggs chill fast if a parent leaves. Not during the first few days of incubation. Not in cold, wet weather. Not at dusk. Tap the box before opening it, and tap again once it is open, so a sitting bird can slip away. Leave by a different route than the one you came in on, so there is no dead-end trail for a predator to follow. Never handle eggs or young; under United States, Canadian and Mexican law, NestWatch notes, it is in most instances illegal to touch or otherwise disturb an active native nest or its contents.

Native plants around the box feed the insects that nestlings eat, a point the butterfly garden pages take up from the planting side, and the main index lists the other guides on this site.

The hardest rule is the last one: once the young are fully feathered and alert, stop opening the box. NestWatch warns that nestlings disturbed at that stage may leave early, and that young which fledge prematurely usually will not stay in the nest even if put back.