Perch Supply
Nest box specification

Barn Owl house dimensions

The Barn Owl nests in barn lofts, silos, tree cavities and large nest boxes A box built to its measurements — and no bigger — is what makes it choose yours.

Barn owls (Tytonidae)Barn OwlTyto alba

The specifications

Entrance hole
6 in
Floor (inside)
16 × 24 in
Mounting height
10–20 ft
Bird size
12.6–15.8 in, 14.1–24.7 oz
Clutch
2–18 eggs
Incubation
29–34 days
Time in nest
50–70 days
Broods
1–3 per season

Build and mounting checklist

  • Drill the entrance to exactly 6 in — oversized holes let in European Starlings and larger predators.
  • No outside perch: cavity nesters don't need one, and it helps House Sparrows and predators.
  • Unpainted interior, 3/4-inch untreated wood (cedar or pine) or poly-lumber for insulation.
  • Drainage holes in the floor corners and ventilation gaps under the roof.
  • A side or front panel that opens so you can monitor and clean the box.
  • Rough or grooved inner front wall so nestlings can climb out.
  • Pole mount with a stovepipe or cone baffle to stop snakes, raccoons and cats.

When to put up a Barn Owl box, by state

Boxes should be up and clean a month before local nesting starts. Dates shift with latitude:

PlaceUp byNestingClean out
British ColumbiaJanuaryFebruary–DecemberJanuary
North DakotaJanuaryFebruary–DecemberJanuary
AlabamaNovemberDecember–DecemberJanuary
ArizonaNovemberDecember–DecemberJanuary
CaliforniaNovemberDecember–DecemberJanuary
FloridaNovemberDecember–DecemberJanuary
GeorgiaNovemberDecember–DecemberJanuary
LouisianaNovemberDecember–DecemberJanuary
MississippiNovemberDecember–DecemberJanuary
South CarolinaNovemberDecember–DecemberJanuary
TexasNovemberDecember–DecemberJanuary
ArkansasDecemberJanuary–DecemberJanuary
DelawareDecemberJanuary–DecemberJanuary
IllinoisDecemberJanuary–DecemberJanuary
IndianaDecemberJanuary–DecemberJanuary
KansasDecemberJanuary–DecemberJanuary
KentuckyDecemberJanuary–DecemberJanuary
MarylandDecemberJanuary–DecemberJanuary
MissouriDecemberJanuary–DecemberJanuary
NebraskaDecemberJanuary–DecemberJanuary
New JerseyDecemberJanuary–DecemberJanuary
New MexicoDecemberJanuary–DecemberJanuary
North CarolinaDecemberJanuary–DecemberJanuary
OhioDecemberJanuary–DecemberJanuary
OklahomaDecemberJanuary–DecemberJanuary
OregonDecemberJanuary–DecemberJanuary
South DakotaDecemberJanuary–DecemberJanuary
TennesseeDecemberJanuary–DecemberJanuary
VirginiaDecemberJanuary–DecemberJanuary
WashingtonDecemberJanuary–DecemberJanuary
West VirginiaDecemberJanuary–DecemberJanuary

Full Barn Owl species guide →

Frequently asked

What size hole does a Barn Owl need?

6 in. A hole cut to this size admits the Barn Owl (12.6–15.8 in) while keeping out larger competitors.

How big should a Barn Owl house be inside?

A floor of 16 × 24 in. The Barn Owl lays 2–18 eggs, so the floor has to hold the full clutch plus growing nestlings.

How high should I mount a Barn Owl box?

10–20 ft. Mount on a pole with a predator baffle where possible rather than a tree or fence.

How long does a Barn Owl use the box?

Incubation takes 29–34 days and the young stay in the nest 50–70 days. Broods per year: 1–3 per season.

Sources

  1. Barn Owl — All About Birds, Cornell Lab of Ornithology
  2. Barn Owl life history — Cornell Lab of Ornithology
  3. Barn Owl — Audubon Guide to North American Birds
  4. NestWatch nest box plans and species requirements — Cornell Lab

Timing reflects typical patterns for the region as a whole; local dates vary with elevation and year. Check the linked eBird bar charts for your county.