--- title: "Nest Box Builder: Birdhouse Plans by Species | Bird Harbor" description: "Pick a bird and get a nest box cut from one 1×6 board: hole size, floor, depth, hole height and mounting from NestWatch, BTO and RSPB, with a cut list." url: https://birdharbor.me/ --- # Build the right nest box for your bird Choose a bird and get a box sized for it: the entrance hole, floor, depth and hole height from NestWatch in North America or the BTO and RSPB in the UK, where to put it, and a cut list for a box made from a single board. ## How the plan works Each bird gets the box its own guidance describes. In North America the entrance hole, inside depth, mounting height, habitat, facing and spacing come from NestWatch, the Cornell Lab of Ornithology’s nest-monitoring project; the height of the hole above the floor comes from Purdue and Nebraska extension guides, because NestWatch’s species pages don’t list it. In the UK and Europe the hole sizes, wood, floor and siting come from the BTO and the RSPB. The plan itself is ours: a simple box from one board, with the front and back at full board width and the two sides fitted between them, a floor set a little way up so it stays dry, and a sloping roof that overhangs the front. The two sides come from one length of board with a single sloping cut. The cut list counts a saw cut between every piece and tells you what is left over. ## Hole size keeps the wrong birds out The entrance is the one measurement to get exactly right. NestWatch notes that House Sparrows can squeeze through a 1 1/4 in (3.2 cm) hole and European Starlings through 1 9/16 in (4 cm), so a smaller hole keeps them out. In the UK, the BTO recommends 25 mm for Blue, Coal and Marsh Tits, 28 mm for Great Tits and Tree Sparrows, and 32 mm for House Sparrows and Nuthatches; a larger hole lets a bigger bird take the box over. ## Ventilation, drainage and no perch NestWatch asks for walls at least 3/4 in thick, two 5/8 in vent holes near the top of each side, four drainage holes or snipped corners in a floor recessed at least 1/4 in, and a roof that overhangs the front. Leave off the perch: birds don’t need it, and the BTO, RSPB and NestWatch all warn that it helps predators. Use untreated wood; in the UK the BTO suggests a water-based preservative on the outside only. ## Sources - NestWatch, Cornell Lab of Ornithology: [Right Bird, Right House](https://nestwatch.org/learn/all-about-birdhouses/right-bird-right-house/) species pages (inside depth, width and length, mounting height, spacing, facing, habitat and tips) for the [Eastern](https://nestwatch.org/learn/all-about-birdhouses/birds/eastern-bluebird/), [Western](https://nestwatch.org/learn/all-about-birdhouses/birds/western-bluebird/) and [Mountain Bluebird](https://nestwatch.org/learn/all-about-birdhouses/birds/mountain-bluebird/), [Tree Swallow](https://nestwatch.org/learn/all-about-birdhouses/birds/tree-swallow/), [House Wren](https://nestwatch.org/learn/all-about-birdhouses/birds/house-wren/), and [Black-capped](https://nestwatch.org/learn/all-about-birdhouses/birds/black-capped-chickadee/), [Carolina](https://nestwatch.org/learn/all-about-birdhouses/birds/carolina-chickadee/) and [Mountain Chickadee](https://nestwatch.org/learn/all-about-birdhouses/birds/mountain-chickadee/); and [Features of a Good Birdhouse](https://nestwatch.org/learn/all-about-birdhouses/features-of-a-good-birdhouse/) (its entrance-size chart, wall thickness, ventilation, drainage, recessed floor, perches and predator guards). - Brian J. MacGowan and Brian K. Miller, [*Size Does Matter: Nest Boxes for Wildlife*](https://www.extension.purdue.edu/extmedia/FNR/FNR-246-W.pdf), Purdue Extension FNR-246-W: hole height above the floor (6–7 in) and floor sizes for bluebirds, chickadees, House Wren and Tree Swallow. - Ron J. Johnson and others, [*Backyard Wildlife: Birdhouses and Shelves*](https://extensionpubs.unl.edu/publication/g2002/na/pdf/view), Nebraska Extension G2002: Mountain Bluebird hole height (6–10 in) and floor (5 × 5 in). - BTO: [Make a nest box](https://www.bto.org/learn/helping-birds/nest-boxes/make-nest-box) (hole sizes, wood at least 15 mm, hinged roof); [*Nest Boxes: Your Essential Guide*](https://www.bto.org/sites/default/files/bto-nest-boxes-essential-guide.pdf) (hole at least 12 cm above the floor, no perch, siting and heights for Blue Tit, House Sparrow and Robin, cleaning between 1 September and 31 January); the [Blue Tit](https://www.bto.org/sites/default/files/blue_tit_nest_box_plan.pdf) and [Robin](https://www.bto.org/sites/default/files/bto-robin-nest-box-plan.pdf) cutting plans (150 mm plank, 175 mm front, 100 mm Robin front, roof groove). - RSPB: [Build a nestbox](https://www.rspb.org.uk/helping-nature/what-you-can-do/activities/build-a-birdbox) (15–18 mm wood, base 150 mm by 150 mm minus twice the thickness, 2–5 m up, facing north to east, hole sizes, open-fronted boxes, rubber hinge); [Our ultimate guide to nestboxes](https://www.rspb.org.uk/helping-nature/what-you-can-do/activities/all-about-nest-boxes) (no perch, 25 mm hole for tits, metal plates, cleaning and the egg-removal dates). ## More from the field journal Every tool names its sources. - [Hummingbird nectar calculator](https://birdharbor.me/hummingbird-nectar-calculator/): Sugar and water for any batch in cups, millilitres and grams, and how often to change it as the weather warms. - [Bird feeder guide](https://birdharbor.me/bird-feeder-guide/): Which birds each food brings in your region, the feeder for it, a cleaning schedule and what never to put out. - [Window collision calculator](https://birdharbor.me/window-collision-calculator/): How many strips or dots a window needs under the 2 × 2 in, 2 × 4 in or Swiss rule, with a printable spacing template. - [Bird count tally](https://birdharbor.me/bird-count-tally/): A backyard count sheet with tap counters, start and stop times and notes, saved on your device, ready for eBird or the Big Garden Birdwatch. - [Bird bath guide](https://birdharbor.me/bird-bath-guide/): Check your bath’s depth, where to put it, how often to clean it and how to keep it safe in winter. ## Recommended Two free services that come in handy for bird watchers online. Disposable email · no sign-up ### CleanTempMail Printable ID charts, nest box plans and bird-festival newsletters often want an email address before you can download. CleanTempMail gives you a free temporary inbox at once: no sign-up, a random or custom address on hundreds of domains, and messages deleted automatically after 3 days. Use your real address for the accounts you keep, such as eBird. [Open a temporary inbox](https://cleantempmail.com/) Disposable cloud browser · domain lookups ### WebTraceCheck Spotted a nest-box camera or bird feeder from a shop you have never heard of? WebTraceCheck’s free DNS and domain lookup shows how old a shop’s domain is, and its disposable cloud browser opens the link on an isolated desktop that is deleted after each session. Nothing to install, with free time every day. [Try WebTraceCheck](https://webtracecheck.com/) ## Questions **Why is the floor smaller than in NestWatch’s plan?** A 1×6 board is only 5 1/2 in wide. With the sides fitted between the front and back, the inside of the box is 4 × 5 1/2 in. NestWatch’s species plans are 5 1/2 in square, which takes wider boards. Purdue Extension lists 4 × 4 in for bluebirds and 4 × 4 to 5 × 5 in for chickadees, House Wrens and Tree Swallows, so the one-board floor is within the sizes extension guides give. **Should I put a perch under the hole?** No. Birds that nest in boxes don’t need a perch, and NestWatch, the BTO and the RSPB all point out that it gives predators and intruders something to hold on to. **When should I put the box up, and when should I clean it?** The RSPB says autumn is best, so birds find the box before spring; many also roost in boxes in winter. In the UK, clean boxes out between 1 September and 31 January, the only time unhatched eggs may be removed (August to January in Scotland). NestWatch advises bluebird hosts to clear out an old nest as soon as a brood fledges, so the box can be used again. **Can I paint or treat the wood?** NestWatch recommends untreated, unpainted wood such as cedar, pine or fir. In the UK the BTO suggests a water-based preservative on the outside of the box only, leaving the inside bare, and the RSPB says to avoid pressure-treated timber and keep paint away from the entrance hole. **Which way should the box face?** It depends on the bird: NestWatch gives east for bluebirds, south or east for Tree Swallows and away from the prevailing wind for Black-capped Chickadees. In the UK the BTO and RSPB suggest between north and east, out of strong sun and the worst of the wind and rain.