Eastern Bluebird nest box
Published dimensions, a cut list for 1×10 (9 1/4 in.), and the placement rules that decide whether the brood survives. The entrance is 1 1/2–1 9/16 in. — cut it to the smaller figure if the range gives you a choice, because a hole bored oversize cannot be made smaller and lets European Starlings in.
Eastern Bluebird
- Entrance hole 1 1/2–1 9/16 in.38–40 mm
- Hole above floor 6–7 in.152–178 mm
- Floor 5 × 5 in.127 × 127 mm
- Cavity depth 9 in.229 mm
- Mounting height 4–6 ft1.2–1.8 m
Habitat and placement: Open country with short grass and scattered perches — pasture edges, orchards, large mown yards, cemeteries. Face the hole away from prevailing wind, ideally toward a shrub or fence 25–100 ft off so fledglings have somewhere to land.
Spacing between boxes: At least 100 yd between boxes (125–150 yd is better). To settle Tree Swallow competition, pair two boxes 5–20 ft apart and space the pairs 100+ yd.
Predator guard: Essential. A stovepipe or conical baffle on a smooth metal pole stops raccoons, cats, and snakes. Avoid wooden posts and fence lines — they are climbing routes.
When to install: Late winter, 4–6 weeks before the first eggs: February in the South, March in the mid-latitudes, early April in the far North. A box put up in June still gets used for second broods.
Notes: Floors of 4×4 in. are also widely used; the 5×5 in. floor gives late-season broods more room. Monitor weekly — House Sparrow nests should be removed, and this box is legal to manage because House Sparrows are nonnative.
Dimensions from: NABS nestbox recommendations; sialis.org spec compilation
No perch. Ever. A perch gives predators and House Sparrows a grip — cavity nesters do not need one.
Cut list
Every board you need, sized so the assembled box matches the published interior above. Pick your stock — the list updates.
1×10 (9 1/4 in.) · about 7 linear feet including waste
| Qty | Piece | Size | Notes |
|---|---|---|---|
| 1 | Floor | 5 × 5 in. | Trim about 1/4 in. off each corner for drainage. |
| 2 | Side | 5 × 11 1/4 in. | Bevel the top edge: 9 3/4 in. at the front rising to 11 1/4 in. at the back. |
| 1 | Back | 6 1/2 × 19 1/4 in. | Runs 4 in. above and 4 in. below the box for mounting screws. |
| 1 | Front | 6 1/2 × 9 3/4 in. | Bore a 1 1/2 in. hole, centred side to side, with its centre 7 3/4 in. up from the bottom edge. |
| 1 | Roof | 9 1/2 × 8 1/2 in. | Overhangs 3 in. at the front and 1 in. each side; butts against the back board. |
Before you cut
- Untreated wood, 3/4 in. thick. Cedar, cypress, or pine. Never pressure-treated, and never paint or stain the interior.
- Score the inside face below the entrance so nestlings can climb out. Smooth plywood traps them.
- Drainage and ventilation. Trim the floor corners; leave gaps or drill holes near the top.
- Make one side or the front open so you can monitor and clean between broods.
- Baffle on a smooth metal pole. This matters more than height, orientation, or anything else on this page.
When and where to put up a nest box — timing by region, habitat matching, orientation, and predator guards that actually work.
Other species
- Western Bluebird 1 9/16 in.
- Mountain Bluebird 1 9/16 in.
- Black-capped Chickadee 1 1/8–1 3/8 in.