Because a new nest is built for each brood, she is wondering if the same robin is recycling its nest or if another robin may have come along to take the easy route to residency.
Robert Payne, U-M professor emeritus of zoology and curator emeritus of birds, guesses that the same female laid the eggs because robins are pretty territorial about their nest. Payne says, “Not to worry, dad will look after his young when they leave the nest" so mom can focus on the new hatchlings.
Many people consider robin sightings the first real sign of spring but the truth is American Robins spend much of the winter in their usual spring and summer locales. American robins – up to hundreds of thousands of them – can gather in a single winter roost, spending less time in yards where more people notice them. The number of robins present in the northern parts of the range varies each year with the local conditions. Some travel to their more southern ranges for part of the winter.
Females sleep on the nests and males gather in roosts during the summertime. As young robins become independent, they join the males in the roost. Female adults go to the roosts only after they are done nesting. An American Robin lays between three to five eggs per clutch and can produce three successful broods in a year. About 40 percent of nests successfully produce young. A quarter of those fledglings survive until late fall. About half of the robins alive in any year will make it to the next. Fortunate robins can reach the ripe old age of 14.
The cup-shaped nest is built by the female, who weaves together the outer foundation with long coarse grass, twigs, paper, and feathers. She lines the inner bowl with mud, smearing it with her breast and then adding fine grass or other soft material to cushion the eggs. The nest can be located on the ground or high up in trees, but most commonly five to 15 feet above ground in dense bushes, in the crotch of trees, or on window ledges or other human structures. In northern areas the first clutch is generally placed in an evergreen tree or shrub, and the later clutches are laid in a deciduous tree.
Dewey, T. and C. Middlebrook. 2001. "Turdus migratorius" (On-line), Animal DiversityWeb. Accessed July 01, 2008.
Sallabanks, R., R. James. 1999. American Robin (Turdus migratorius). Birds of North America, 462: 1-20.
Submitted by Shirley Spence, Monroe, Mich., bottom photo: Shirley Spence with special thanks to Shirley who loves the fun facts page!