An American Robin can produce three successful broods in one year. On average, though, only 40 percent of nests successfully produce young. Only 25 percent of those fledged young survive to November. From that point on, about half of the robins alive in any year will make it to the next. Despite the fact that a lucky robin can live to be 14 years old, the entire population turns over on average every six years.
Females build the nest from the inside out, pressing dead grass and twigs into a cup shape using the wrist of one wing. Other materials include paper, feathers, rootlets, or moss in addition to grass and twigs. Once the cup is formed, she reinforces the nest using soft mud gathered from worm castings to make a heavy, sturdy nest. She then lines the nest with fine dry grass. The finished nest is 6-8 inches across and 3-6 inches high. The process from egg laying to fledging lasts about a month.
The parents feed their chicks 3-4 bites every 30 – 60 minutes, and robins often raise more than one brood during the season. I’ve seen studies which conclude that the red inside the chick’s gaping mouth, along with the “feed me” chirp, stimulates the adults to feed the babies. This is lucky for birds since they foster chicks which aren’t their own quite easily.
She does look surprised to find the chicks have left the nest, doesn’t she? I enjoyed this great summary of the effort the birds put into raising their young and hope you enjoy it too.