Nest boxes · Iowa

Birdhouses for Iowa

20 cavity-nesting birds breed in Iowa. The first starts nesting in January, so the box season opens in December.

Local conditions

Growing zones: USDA 4b–6a
Winter: Cold, windy winters; open farmland makes backyard shelter and feeders a lifeline.
Summer: Hot, humid summers with thunderstorms.
Box nesters: 20 (14 year-round residents)
Hole sizes needed: 15 distinct

Humid continental prairie state, with loess hills in the west and the Driftless Area in the northeast.

Box calendar for Iowa

Bird	Status	Hole	Height	Up by	Nesting	Clean out
Barred Owl	Year-round resident	7–8 in	12–20 ft	December	January–May	June
Hooded Merganser	Year-round resident	4 × 3 in oval	6–20 ft	January	February–May	June
Eastern Screech-Owl	Year-round resident	3 in	10–30 ft	February	March–May	June
American Kestrel	Year-round resident	3 in	10–30 ft	February	March–June	July
Wood Duck	Year-round resident	4 × 3 in oval	6–20 ft	February	March–June	July
Eastern Bluebird	Summer breeder	1 1/2 in round (1 9/16 in for Mountain/Western overlap)	4–6 ft on a baffled pole	March	April–August	September
Black-capped Chickadee	Year-round resident	1 1/8 in round	5–15 ft	March	April–July	August
Downy Woodpecker	Year-round resident	1 1/4 in round	5–20 ft, box packed with wood shavings	March	April–June	July
Hairy Woodpecker	Year-round resident	1 1/2 in round	8–20 ft, box packed with wood shavings	March	April–June	July
Tufted Titmouse	Year-round resident	1 1/4 in round	5–15 ft	March	April–June	July
White-breasted Nuthatch	Year-round resident	1 1/4 in round	5–20 ft	March	April–June	July
Carolina Wren	Year-round resident	1 1/8–1 1/2 in	5–10 ft	March	April–August	September
Red-bellied Woodpecker	Year-round resident	2 1/2 in	12–20 ft	March	April–July	August
Northern Flicker	Year-round resident	2 1/2 in	6–20 ft	March	April–June	July
Prothonotary Warbler	Summer breeder	1 1/8 in	3–6 ft over water	March	April–June	July
Eurasian Tree Sparrow	Year-round resident	1 1/4 in	6–15 ft	March	April–August	September
Purple Martin	Summer breeder	1 3/4–2 1/8 in round, or starling-resistant crescent (3 × 1 3/16 in)	10–20 ft on a telescoping pole, 40+ ft from trees	April	May–July	August
House Wren	Summer breeder	1 to 1 1/8 in round	5–10 ft near shrubs	April	May–August	September
Tree Swallow	Summer breeder	1 1/2 in	5–10 ft	April	May–June	July
Great Crested Flycatcher	Summer breeder	1 3/4 in	8–20 ft	April	May–July	August

Nesting windows are shifted from each species' mid-latitude season by Iowa's latitude; year-round residents may also roost in boxes over winter, so clean them out in autumn and leave them up.

Frequently asked

When should I put up a birdhouse in Iowa?

By December for the earliest local nester, the Barred Owl, which starts nesting around January.

Which birds use nest boxes in Iowa?

Barred Owl, Hooded Merganser, Eastern Screech-Owl, American Kestrel, Wood Duck, Eastern Bluebird, Black-capped Chickadee, Downy Woodpecker, Hairy Woodpecker, Tufted Titmouse, White-breasted Nuthatch, Carolina Wren, Red-bellied Woodpecker, Northern Flicker, Prothonotary Warbler, Eurasian Tree Sparrow, Purple Martin, House Wren, Tree Swallow, Great Crested Flycatcher.

What hole size should a Iowa birdhouse have?

It depends on the bird: the 20 local box nesters use 15 different hole sizes. See the table for each species.

Sources

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.