New Decade Sees Earliest Robin Eggs in Nestwatch History

By Gustave Axelson
March 30, 2020
An early January attempt sets a NestWatch record for earliest American Robin nest. Photo by Zina Horne.An early January attempt sets a NestWatch record for earliest American Robin nest. Photo by Zina Horne.

From the Spring 2020 issue of Living Bird magazine. Subscribe now.

The Cornell Lab of Ornithology’s NestWatch project started off the 2020s with a new record—the earliest egg laid by an American Robin in the citizen-science project’s 23-year history.

In early January, NestWatch participant Ed Laster reported three eggs in a robin’s nest in his neighbor’s backyard in Arkansas. NestWatch project leader Robyn Bailey suspects the eggs were likely laid sometime before January 6—the earliest robin clutch that could be verified in the NestWatch data (a robin nest with eggs in Kentucky was reported on January 5 in 2015, but that record could not be verified).

Bailey hypothesizes that the subtle increase in day length after the winter solstice, not higher temperatures, might have stimulated this pair of robins to begin the nesting process, because it is increasing day length in spring that triggers the hormones responsible for reproduction in most temperate songbirds.

“This robin’s nest is certainly an outlier rather than a new trend,” says Bailey. “While it’s true that some species are shifting to earlier egg-laying as spring temperatures warm, those shifts are measured in days, perhaps weeks—but not months. We don’t know if these eggs were even fertilized.”

Laster later reported the robin eggs in Arkansas were abandoned as of January 13, which is a common outcome for such an early nest, says Bailey.

Join Nestwatch

NestWatch is a Cornell Lab’s citizen-science program that tracks the reproductive success of birds to answer questions about how bird populations are faring—being a part of Nestwatch is a great way to help birds!

Whether at your home, workplace, or school, you can report nests you find. Visit the Nestwatch website or download the NestWatch app today to report nests you discover and help advance our understanding of birds.

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