Prothonotary Warbler 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 1/8–1 1/4 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.
Prothonotary Warbler
- Entrance hole 1 1/8–1 1/4 in.29–32 mm
- Hole above floor 6–8 in.152–203 mm
- Floor 4 × 5 1/2 in.102 × 140 mm
- Cavity depth 8–10 in.203–254 mm
- Mounting height 4–8 ft1.2–2.4 m
Habitat and placement: Flooded bottomland forest, cypress swamp, and wooded riverbank. The one warbler that nests in cavities — and it wants the box over or beside standing water.
Spacing between boxes: One box per 100 ft of shoreline works well on a good swamp edge.
Predator guard: Baffle on the pole. Over water, a metal pole plus cone stops both raccoons and rat snakes.
When to install: March, before the first males arrive in April.
Notes: Add a shallow layer of moss or leave it bare — the birds bring their own moss. A box mounted over water gets used far more often than the same box 50 ft inland.
Dimensions from: 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 | 4 × 5 1/2 in. | Trim about 1/4 in. off each corner for drainage. |
| 2 | Side | 5 1/2 × 12 1/4 in. | Bevel the top edge: 10 3/4 in. at the front rising to 12 1/4 in. at the back. |
| 1 | Back | 5 1/2 × 20 1/4 in. | Runs 4 in. above and 4 in. below the box for mounting screws. |
| 1 | Front | 5 1/2 × 10 3/4 in. | Bore a 1 1/8 in. hole, centred side to side, with its centre 8 3/4 in. up from the bottom edge. |
| 1 | Roof | 10 × 7 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
- Purple Martin 2–2 1/2 in.
- American Robin open front
- Eastern Phoebe open front