Perch Supply
Nest box specification

Tree Swallow house dimensions

The Tree Swallow nests in nest box or tree cavity lined with feathers A box built to its measurements — and no bigger — is what makes it choose yours.

Swallows (Hirundinidae)Tree SwallowTachycineta bicolor

The specifications

Entrance hole
1 1/2 in
Floor (inside)
5 × 5 in
Mounting height
5–10 ft
Bird size
4.7–5.9 in, 0.6–0.9 oz
Clutch
4–7 eggs
Incubation
11–20 days
Time in nest
15–25 days
Broods
1 per season

Build and mounting checklist

  • Drill the entrance to exactly 1 1/2 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 Tree Swallow box, by state

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

PlaceUp byNestingClean out
ArizonaMarchApril–JuneJuly
CaliforniaMarchApril–JuneJuly
ColoradoAprilMay–JuneJuly
ConnecticutAprilMay–JuneJuly
DelawareAprilMay–JuneJuly
IdahoAprilMay–JuneJuly
IllinoisAprilMay–JuneJuly
IndianaAprilMay–JuneJuly
IowaAprilMay–JuneJuly
KansasAprilMay–JuneJuly
KentuckyAprilMay–JuneJuly
MarylandAprilMay–JuneJuly
MassachusettsAprilMay–JuneJuly
MichiganAprilMay–JuneJuly
MissouriAprilMay–JuneJuly
NebraskaAprilMay–JuneJuly
NevadaAprilMay–JuneJuly
New JerseyAprilMay–JuneJuly
New MexicoAprilMay–JuneJuly
New YorkAprilMay–JuneJuly
North CarolinaAprilMay–JuneJuly
OhioAprilMay–JuneJuly
OklahomaAprilMay–JuneJuly
OregonAprilMay–JuneJuly
PennsylvaniaAprilMay–JuneJuly
Rhode IslandAprilMay–JuneJuly
South DakotaAprilMay–JuneJuly
TennesseeAprilMay–JuneJuly
UtahAprilMay–JuneJuly
VirginiaAprilMay–JuneJuly
WashingtonAprilMay–JuneJuly
West VirginiaAprilMay–JuneJuly
AlaskaMayJune–JuneJuly
AlbertaMayJune–JuneJuly
British ColumbiaMayJune–JuneJuly
MaineMayJune–JuneJuly
ManitobaMayJune–JuneJuly
MinnesotaMayJune–JuneJuly
MontanaMayJune–JuneJuly
New BrunswickMayJune–JuneJuly
New HampshireMayJune–JuneJuly
Newfoundland and LabradorMayJune–JuneJuly
North DakotaMayJune–JuneJuly
Northwest TerritoriesMayJune–JuneJuly
Nova ScotiaMayJune–JuneJuly
OntarioMayJune–JuneJuly
Prince Edward IslandMayJune–JuneJuly
QuebecMayJune–JuneJuly
SaskatchewanMayJune–JuneJuly
VermontMayJune–JuneJuly
WisconsinMayJune–JuneJuly
WyomingMayJune–JuneJuly
YukonMayJune–JuneJuly

Full Tree Swallow species guide →

Frequently asked

What size hole does a Tree Swallow need?

1 1/2 in. A hole cut to this size admits the Tree Swallow (4.7–5.9 in) while keeping out larger competitors.

How big should a Tree Swallow house be inside?

A floor of 5 × 5 in. The Tree Swallow lays 4–7 eggs, so the floor has to hold the full clutch plus growing nestlings.

How high should I mount a Tree Swallow box?

5–10 ft. Mount on a pole with a predator baffle where possible rather than a tree or fence.

How long does a Tree Swallow use the box?

Incubation takes 11–20 days and the young stay in the nest 15–25 days. Broods per year: 1 per season.

Sources

  1. Tree Swallow — All About Birds, Cornell Lab of Ornithology
  2. Tree Swallow life history — Cornell Lab of Ornithology
  3. Tree Swallow — 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.