Baby cowbirds: from egg to fledgling
A Brown-headed Cowbird lays Up to 36 eggs per season, one per host nest. They hatch after 10–12 days, and the young leave the nest 8–13 days later — about 18–25 days from egg to fledgling.
- Eggs per clutch
- Up to 36 eggs per season, one per host nest
- Incubation
- 10–12 days
- Time in the nest
- 8–13 days
- Egg to fledgling
- About 18–25 days
- Broods per year
- —
- Nest
- Builds no nest — lays eggs in the nests of other species
- Uses nest boxes
- No
Stage by stage
- Eggs (10–12 days): Up to 36 eggs per season, one per host nest per clutch. Most songbirds start incubating when the last or second-to-last egg is laid, so the young hatch close together; owls and hawks start with the first egg, so their chicks hatch days apart.
- Nestlings (8–13 days): the young hatch with little or no down and their eyes closed. They grow fast on a diet the parents bring in. In the breeding season cowbirds mainly eat grasshoppers, beetles and grass seeds.
- Fledglings: after leaving the nest, young cowbirds are fully feathered but short-tailed and clumsy. They spend days to weeks on low branches or the ground while the parents keep feeding them.
- More broods: —.
When cowbirds nest, state by state
Nesting starts earliest in Alabama (Mar) and latest in Alberta (May). Months are estimates from regional breeding data shifted for latitude.
| State / province | Nesting season |
|---|---|
| Alabama | Mar–Jul |
| Alberta | May–Jul |
| Arizona | Mar–Jul |
| Arkansas | Apr–Jul |
| British Columbia | May–Jul |
| California | Mar–Jul |
| Colorado | Apr–Jul |
| Connecticut | Apr–Jul |
| Delaware | Apr–Jul |
| Florida | Mar–Jul |
| Georgia | Mar–Jul |
| Idaho | Apr–Jul |
| Illinois | Apr–Jul |
| Indiana | Apr–Jul |
| Iowa | Apr–Jul |
| Kansas | Apr–Jul |
| Kentucky | Apr–Jul |
| Louisiana | Mar–Jul |
| Maine | May–Jul |
| Manitoba | May–Jul |
| Maryland | Apr–Jul |
| Massachusetts | Apr–Jul |
| Michigan | Apr–Jul |
| Minnesota | May–Jul |
| Mississippi | Mar–Jul |
| Missouri | Apr–Jul |
| Montana | May–Jul |
| Nebraska | Apr–Jul |
| Nevada | Apr–Jul |
| New Brunswick | May–Jul |
| New Hampshire | May–Jul |
| New Jersey | Apr–Jul |
| New Mexico | Apr–Jul |
| New York | Apr–Jul |
| North Carolina | Apr–Jul |
| North Dakota | May–Jul |
| Northwest Territories | May–Jul |
| Nova Scotia | May–Jul |
| Ohio | Apr–Jul |
| Oklahoma | Apr–Jul |
| Ontario | May–Jul |
| Oregon | Apr–Jul |
| Pennsylvania | Apr–Jul |
| Quebec | May–Jul |
| Rhode Island | Apr–Jul |
| Saskatchewan | May–Jul |
| South Carolina | Mar–Jul |
| South Dakota | Apr–Jul |
| Tennessee | Apr–Jul |
| Texas | Mar–Jul |
| Utah | Apr–Jul |
| Vermont | May–Jul |
| Virginia | Apr–Jul |
| Washington | Apr–Jul |
| West Virginia | Apr–Jul |
| Wisconsin | May–Jul |
| Wyoming | May–Jul |
| Yukon | May–Jul |
Found a baby Brown-headed Cowbird?
- Feathered, hopping, can grip your finger: a fledgling. This is a normal stage. Keep pets and children away and watch from a distance; the parents are usually close by.
- Bare skin or only pin feathers: a nestling that fell. If you can see the nest, put it back. Touching it won't make the parents abandon it — that is a myth.
- Injured, cold, covered in flies, or caught by a cat: contact a licensed wildlife rehabilitator. In the US and Canada, ahnow.org finds the nearest one.
- Don't give water or food. Baby birds can choke, and the wrong food can kill them.
More about cowbirds
Frequently asked
How long do baby cowbirds stay in the nest?
About 8–13 days after hatching. Eggs take 10–12 days to hatch, so it is roughly 18–25 days from the last egg to the young leaving.
How many eggs does a Brown-headed Cowbird lay?
Up to 36 eggs per season, one per host nest per clutch, with —.
Where do cowbirds nest?
Builds no nest — lays eggs in the nests of other species.
What should I do if I find a baby Brown-headed Cowbird on the ground?
If it has feathers and hops, it is a fledgling and its parents are almost certainly nearby — leave it. If it is naked or has pin feathers, put it back in the nest if you can. Call a licensed wildlife rehabilitator if it is injured.