Tree Swallow birdhouse dimensions & cut list

The exact entrance hole, floor size, depth, and mounting height for a Tree Swallow nest box — plus a cut-list generator for your lumber and a printable diagram.

Quick-answer dimensions

Entrance hole
1.38 in round
1 3/8" round (NestWatch); a common size where bluebirds also nest.
Hole height above floor
6 in
Floor (interior)
5.5 x 5.5 in
5 1/2 x 5 1/2 in (NestWatch).
Interior depth
9 in
Interior height 9 in (NestWatch); entrance ~6 in above the floor.
Mounting height
5-6 ft
Habitat
Open fields, meadows, and shorelines near water; few trees.

Cut-list generator

Printable dimension diagram

Front 5.5 in floor 1.38 in round 6 in Side 5.5 in deep 9 in

Placement & mounting

Mounting height5-6 ft
HabitatOpen fields, meadows, and shorelines near water; few trees.
Placement notesPlace 5-6 ft up in the open near water/fields, facing south or east (NestWatch). Pairing with a bluebird box 20-25 ft away reduces competition. Add a 'fledgling ladder' (kerf cuts or hardware cloth) under the hole so chicks can climb out.

Materials & cautions

Materials checklist

  • 3/4 in untreated cedar or pine (~1x6 board, ~3.5 ft)
  • 1 1/4 in galvanized or exterior deck screws
  • 1 3/8 in spade/Forstner bit
  • Fledgling ladder (kerf cuts or hardware cloth) under the entrance
  • Drainage + vent gaps

Cautions

  • Open-habitat species; will not use boxes set in woods.
  • No perch.
  • Competes with bluebirds and House Sparrows; monitor.
Sources & how the cut list is computed

The biological requirements above (entrance hole 1.38 in round, floor 5.5x5.5 in, interior depth 9 in, entrance 6 in above the floor, mounting 5-6 ft) are taken from the sources below and last reviewed 2026-06-18.

Data basis: NestWatch 'Right Bird, Right House' — Tree Swallow (1 3/8 in hole, 5 1/2 x 5 1/2 in floor, 9 in interior depth, 5-6 ft height, faces south/east, ~35 ft spacing), fetched 2026-06-18.

The interactive cut-list is DETERMINISTIC GEOMETRY, not an official plan. It assumes a simple back-mounted butt-joint box: the front and back panels overlap the two side panels (front/back width = interior floor width + 2x board thickness), the side panels fit between them (side run = interior floor depth), the floor sits inside (interior floor width x depth), and the roof overhangs. Heights come from the species cavity depth; a sloped roof makes the back panel taller than the front by the chosen slope. It is labeled a STARTING cut list; users should verify against the linked official plan and their own joinery.

Hobby-woodworking and backyard-habitat information only. Not wildlife-rescue, veterinary, or medical advice. Follow local regulations; for native cavity-nesters, monitor responsibly and control invasive House Sparrows and European Starlings per local guidance.

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