Oregon · Summer breeder

Tree Swallows in Oregon

When tree swallows are present in Oregon, when they nest, which native Oregon plants feed them, and how to host them in a USDA 4b–9b yard.

Swallows (Hirundinidae)Tree SwallowTachycineta bicolor
Status in Oregon
Summer breeder
Nesting window
May–June
Broods
1 per season
Hardiness zones
USDA 4b–9b
Nest box
1 1/2 in hole, 5 × 5 in floor, 5–10 ft

When to expect tree swallows in Oregon

Tree Swallows are summer residents in Oregon, arriving shortly before nesting begins in May and leaving after the young are independent. Through the season they feed on flies, mayflies and dragonflies.

Marine west-coast climate west of the Cascades; high desert to the east.

Nesting in Oregon

Across Oregon, tree swallows typically nest from May–June. Nest site: nest box or tree cavity lined with feathers. Females lay 4–7 eggs, incubate for 11–20 days, and young leave the nest after 15–25 days.

Dry summers west of the Cascades; hot days in the high desert.

  • Have boxes cleaned and mounted before April — tree swallows begin prospecting ahead of egg-laying.
  • Use a 1 1/2 in entrance on a 5 × 5 in floor, mounted 5–10 ft.
  • Fit a pole baffle or hole guard; ventilation gaps and drainage holes are essential.
  • Clean out old nests after each brood and again after June.

Native Oregon plants that attract tree swallows

Of the regional native plants we track for Oregon, these 8 provide food or cover tree swallows use:

Tall goldenrod
Solidago altissima · Perennial

Insect-rich in fall and seed in winter.

Paper birch
Betula papyrifera · Tree

Catkin seed feeds redpolls and siskins all winter.

Chokecherry
Prunus virginiana · Shrub

Dark summer fruit and heavy caterpillar load.

Ponderosa pine
Pinus ponderosa · Tree

Seeds and bark insects; pygmy nuthatch and woodpecker habitat.

Rabbitbrush
Ericameria nauseosa · Shrub

Late-season bloom supports insects; seed for sparrows.

Oregon white oak
Quercus garryana · Tree

Acorns and a rich insect community in the Pacific Northwest.

Douglas fir
Pseudotsuga menziesii · Tree

Seed for crossbills, siskins and chickadees.

Willow (Bebb)
Salix bebbiana · Shrub

Early catkins draw insects for arriving warblers and hummingbirds.

Feeding tree swallows through the Oregon year

Tree swallows readily take bluebird-style nest boxes; mount boxes in pairs 15–25 ft apart to share with bluebirds.

  • Best foods: Crushed eggshells in spring.
  • In Oregon's summer: offer water and insect foods; natural food is abundant.

Full diet breakdown for tree swallows · Best feeder for tree swallows

Frequently asked

Are tree swallows in Oregon year-round?

No. Tree Swallows are summer breeders in Oregon and leave for the winter.

When do tree swallows nest in Oregon?

Nesting in Oregon typically runs May–June, with 1 per season. Clutches are 4–7 eggs, incubated for 11–20 days.

What native plants attract tree swallows in Oregon?

Tall goldenrod, Paper birch, Chokecherry, Ponderosa pine, Rabbitbrush, Oregon white oak, Douglas fir, Willow (Bebb) are native plants in Oregon that provide food or cover for tree swallows.

What size birdhouse hole do tree swallows need?

1 1/2 in, with a floor of 5 × 5 in mounted 5–10 ft.

Tree Swallows in other regions

Other backyard birds in Oregon

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
  5. eBird region overview and bar charts — Oregon
  6. USDA Plant Hardiness Zone Map (2023)
  7. Audubon Native Plants Database

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.