American Robin

Turdus migratorius

Winter Trend: Increasing

Graph showing American Robin winter population trend in New Hampshire from 1987 to 2025, with model prediction and 95% confidence interval.

American Robins, 1987–2025.

The dark purple line shows the trend over time predicted by our statistical model, while the shaded purple area shows where we are 95% confident the true trend lies. Gray points are the number of robins actually observed in participants’ backyards, averaged per observer.

What’s the Story?

American Robins were once considered a sign of spring, but that’s changing. Today, American Robins overwinter across much of New Hampshire, though they are less common in Coos County and the White Mountains. Large flocks are now commonly seen even in the dead of winter.

Our statistical analysis confirms this increase: a negative binomial regression shows a significant upward trend (β = 0.108 ± 0.014 SE, z = 7.801, p < 0.001).

This translates to reports of robins increasing by about 11% per year, even when accounting for changes in the number of Backyard Winter Bird Survey participants over time.

This increase is likely due to a combination of warmer winters and more ornamental fruit trees in yards and landscapes. These ornamental trees provide fruit through the winter, a key component of their diet. Slightly warmer winters also benefit this species that’s range had previously been limited by cold and snow cover.

Feeding Tips

  • Dried mealworms are a favorite food of American Robins at feeders in winter.
  • Robins will also eat raisins, currants, dried figs, and other dried fruit softened in warm water for 20–30 minutes and placed on a flat surface.
  • Robins don’t typically feed at hanging feeders; offer food on a table or feeder platform instead.
  • American robins will also feed at suet feeders.

In Your Backyard

  • Look for large flocks of robins in areas with abundant fruit-bearing shrubs or trees like sumac, holly, and crabapple.
  • Providing unfrozen water in a birdbath can be a welcome resource for drinking and bathing.
  • Leave a little mess in the garden. Unraked leaves and debris can create additional foraging opportunities.

ID Tips

American Robin on a fruit branch.

American Robin by Grace McCulloch.

Larger than most songbirds, American Robins have gray on the back and orange breasts. Also, look for the dark head with a white eye-ring

Want to Learn More? Visit the State of the Birds!

Turdus migratorius

Understanding the Graph and Statistics

Observed Data (gray points):

The average number of birds counted per participant each year.

Model-Predicted Trend (dark purple line):

A line from a statistical model that estimates the overall trend in bird numbers over time, smoothing out year-to-year fluctuations.

95% Confidence Interval (shaded purple area):

The range around the predicted trend where we are 95% confident the true trend lies. Gray points inside this band indicate observations that are consistent with the predicted trend.

Other Stats You Might See in the Story:

  • β (slope) and SE (standard error): These numbers tell us how strongly and precisely the bird counts are changing each year.
  • p-value and z-value: These tell us whether the observed trend is statistically significant (i.e., very unlikely to be due to random chance). For example, a p-value less than 0.05 usually means a statistically significant trend in either direction.

The Takeaway: These graphs show how bird populations are changing over time. The model helps us see the overall trend and the confidence interval shows how certain we are about that trend.