Barn Swallow eggs
White, spotted with brown, lavender and gray, about 0.63–0.87 inches long — roughly the width of a US quarter. A Barn Swallow lays 3–7 eggs, and they hatch after 12–17 days.
- Color
- White, spotted with brown, lavender and gray
- Length
- 0.63–0.87 in (16–22 mm)
- Width
- 0.51–0.59 in (13–15 mm)
- Eggs per clutch
- 3–7 eggs
- Incubation
- 12–17 days
- Broods per year
- 1–2 per season
- Nest
- Mud cup on beams and ledges under shelter
How to recognise a Barn Swallow egg
- Color: white, spotted with brown, lavender and gray. Markings vary between females and are often heaviest around the wide end; the same female tends to lay a similar pattern every time.
- Size: 16–22 mm long by 13–15 mm wide. For scale, a US quarter is 24.3 mm across, so this egg is roughly the width of a US quarter.
- Where you find it: mud cup on beams and ledges under shelter. Barn swallows do not normally use nest boxes.
- Clutch: 3–7 eggs. A nest with far more eggs than this may hold eggs from two females, or a cowbird egg laid by a brood parasite.
Eggs that look similar
These species lay eggs in the same color group, sorted by how close they are in length. Size and nest site usually settle it.
| Species | Egg | Length |
|---|---|---|
| Barn Swallow | white, spotted with brown, lavender and gray | 16–22 mm |
| White-breasted Nuthatch | creamy white or pinkish, speckled with reddish brown | 18–20 mm |
| Carolina Wren | white or pinkish, speckled with brown | 17–20 mm |
| Dark-eyed Junco | whitish or pale bluish, speckled with brown and gray | 19–21 mm |
| House Finch | pale bluish white, finely speckled with black and lavender | 16–25 mm |
When barn swallows lay eggs, state by state
Laying starts earliest in Alabama (Apr) and latest in Alaska (Jun). Months are estimates from regional breeding data shifted for latitude.
From egg to fledgling
Eggs hatch after 12–17 days and the young leave 15–27 days later. See the full baby Barn Swallow guide for nestling stages and what to do if you find one on the ground.
Found eggs in your yard?
- Leave them. Parents often step away for long stretches, especially before the full clutch is laid, because most songbirds do not start incubating until the last or second-to-last egg.
- A single egg on the ground is usually lost for good. Eggs cannot be hatched at home, and possession of native bird eggs is illegal without a permit.
- If a nest is somewhere inconvenient, wait it out. Most small songbirds are done in three to five weeks.
- Watch from a distance and keep pets indoors. Repeated visits can lead predators to the nest.
Questions
Frequently asked
What color are Barn Swallow eggs?
White, spotted with brown, lavender and gray.
How big is a Barn Swallow egg?
About 0.63–0.87 in long and 0.51–0.59 in wide (16–22 × 13–15 mm) — roughly the width of a US quarter.
How many eggs does a Barn Swallow lay?
3–7 eggs per clutch, usually one egg a day, with 1–2 per season.
How long until Barn Swallow eggs hatch?
Incubation takes 12–17 days. The young then stay in the nest 15–27 days — about 27–44 days from incubation to leaving.
Can I move or touch a Barn Swallow nest with eggs?
No. Native birds, their nests and eggs are protected under the Migratory Bird Treaty Act. Wait until the young have left before removing an old nest.
Sources
- Cornell Lab of Ornithology — All About Birds: Barn Swallow life history
- U.S. Fish & Wildlife Service — Migratory Bird Treaty Act
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.