While adult American Robins (Turdus migratorius) may be a common sight, their nests are often tucked away in thickets and hard to access areas. Today, however, while performing a wetland delineation for work, I stumbled across this nest. The female robin chooses the nest site and is primarily responsible for building the nest itself, although males will help to collect nest materials. Nests are typically situated on one or more horizontal branches hidden in or just below a layer of dense leaves – exactly where I spotted this nest. Additionally, robin nests are generally assembled in the lower parts of trees and shrubs; this nest was only about 4 feet off the ground. Robins construct their nest of mud, grass and small twigs, and from the looks of this particular nest, will also incorporate bits of trash (if you look under the chin of the chick to the right, you’ll see a bit of what looks like plastic).
The four American Robin chicks in this nest had grown large enough at this point that they hardly fit in the nest together. (For scale, the interior portion of a robin’s nest is approximately the same size as a baseball.) For the entire time I was in their immediate vicinity, they didn’t move or make a sound. In fact, they hardly blinked. I can only assume both parents were out foraging at the time I encountered the nest, because although American Robins are known to aggressively defend their nests, I didn’t notice any adult robins, let alone any producing alarm calls or trying to dive-bomb me.
According to All About Birds, American Robins can successfully produce 3 broods in a single year, but only about 40% of nests produce fledglings. Given that the four chicks in this nest all seemed healthy, it seems like this nest will at least produce successful fledglings. American Robin chicks tend to fledge about 2 weeks after hatching, which based on their size, will be soon. However, records show that only about a quarter of those that do fledge will survive to November. This somewhat low survival rate may account for American Robins’ inclination to lay multiple broods in a season.
Have you noticed any birds’ nests this year?