Eastern Bluebird eggs
Pale blue, occasionally white, about 0.71–0.83 inches long — roughly the width of a US quarter. A Eastern Bluebird lays 2–7 eggs, and they hatch after 11–19 days.
- Color
- Pale blue, occasionally white
- Length
- 0.71–0.83 in (18–21 mm)
- Width
- 0.63–0.67 in (16–17 mm)
- Eggs per clutch
- 2–7 eggs
- Incubation
- 11–19 days
- Broods per year
- 1–3 per season
- Nest
- Secondary cavity nester — old woodpecker holes and nest boxes in open habitat
How to recognise a Eastern Bluebird egg
- Color: pale blue, occasionally white. There are no markings on a fresh egg, though eggs pick up stains from the nest as incubation goes on.
- Size: 18–21 mm long by 16–17 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: secondary cavity nester — old woodpecker holes and nest boxes in open habitat. Bluebirds also use nest boxes with a 1 1/2 in round (1 9/16 in for Mountain/Western overlap) entrance, so eggs in a box are a strong clue.
- Clutch: 2–7 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 |
|---|---|---|
| Eastern Bluebird | pale blue, occasionally white | 18–21 mm |
| Chipping Sparrow | pale blue-green with sparse dark brown and black marks, mostly at the large end | 16–19 mm |
| American Goldfinch | pale bluish white, sometimes with faint spots | 15–17 mm |
| Gray Catbird | turquoise or greenish blue, unmarked | 21–26 mm |
| Wood Thrush | pale blue or blue-green, unmarked | 24–28 mm |
When bluebirds lay eggs, state by state
Laying starts earliest in Alabama (Mar) and latest in Maine (May). Months are estimates from regional breeding data shifted for latitude.
| State / province | Nesting season |
|---|---|
| Alabama | Mar–Aug |
| Arizona | Mar–Aug |
| Arkansas | Apr–Aug |
| Connecticut | Apr–Aug |
| Delaware | Apr–Aug |
| Florida | Mar–Jul |
| Georgia | Mar–Aug |
| Illinois | Apr–Aug |
| Indiana | Apr–Aug |
| Iowa | Apr–Aug |
| Kansas | Apr–Aug |
| Kentucky | Apr–Aug |
| Louisiana | Mar–Aug |
| Maine | May–Aug |
| Manitoba | May–Aug |
| Maryland | Apr–Aug |
| Massachusetts | Apr–Aug |
| Michigan | Apr–Aug |
| Minnesota | May–Aug |
| Mississippi | Mar–Aug |
| Missouri | Apr–Aug |
| Nebraska | Apr–Aug |
| New Brunswick | May–Aug |
| New Hampshire | May–Aug |
| New Jersey | Apr–Aug |
| New York | Apr–Aug |
| North Carolina | Mar–Aug |
| North Dakota | May–Aug |
| Nova Scotia | May–Jul |
| Ohio | Apr–Aug |
| Oklahoma | Apr–Aug |
| Ontario | May–Aug |
| Pennsylvania | Apr–Aug |
| Quebec | May–Aug |
| Rhode Island | Apr–Aug |
| Saskatchewan | May–Aug |
| South Carolina | Mar–Aug |
| South Dakota | Apr–Aug |
| Tennessee | Apr–Aug |
| Texas | Mar–Jul |
| Vermont | May–Aug |
| Virginia | Mar–Aug |
| West Virginia | Apr–Aug |
| Wisconsin | May–Aug |
From egg to fledgling
Eggs hatch after 11–19 days and the young leave 15–20 days later. See the full baby Eastern Bluebird 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 Eastern Bluebird eggs?
Pale blue, occasionally white.
How big is a Eastern Bluebird egg?
About 0.71–0.83 in long and 0.63–0.67 in wide (18–21 × 16–17 mm) — roughly the width of a US quarter.
How many eggs does a Eastern Bluebird lay?
2–7 eggs per clutch, usually one egg a day, with 1–3 per season.
How long until Eastern Bluebird eggs hatch?
Incubation takes 11–19 days. The young then stay in the nest 15–20 days — about 26–39 days from incubation to leaving.
Can I move or touch a Eastern Bluebird 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: Eastern Bluebird 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.