Yesterday I was walking to the gym and I saw a swarm of robins on the ground.
I live in Chicago and was walking east on Fullerton, and I walked over the Chicago River and there they were. I never saw so many robins.
I counted 50 of them, then crossed the street and there were at least another 50 of them.
I assume these robins were flying south and stopped over because maybe 'cause of the river. But I don’t ever recall seeing that many. There was at least 100 of them.
Is this normal, 'cause I’ve never seen that before.
According to this site, robins form loose flocks when migrating. It also notes that they may congregate in locations of unfrozen water or rich food supply along the way. I assume that’s less of a flocking behavior and more of a “this is where the action’s at” thing.
Until recently I don’t ever recall seeing robins during the winter (they really were the “harbingers of spring”), and never more than a few at a time. Lately I’m seeing more of them all winter long, and in larger numbers. Could this be some sort of adaptation? If it is, it’s happening damn fast!
Thanks for that site. Boy that tells you EVERYTHING about robins. Fascinating info.
Apparently they do migrate together, usually 10 -15 but they will gather in flocks of a hundred or more if there is food.
The site also says that robins don’t care so much about the cold. Even if it’s below zero temps. As long as they got plenty of food they don’t have trouble finding places to stay warm. So if there is lots of food they will often stay put.
If they can’t eat worms and other insects then they eat fruit and berries.
There is extensive evidence that global warming has changed migration times, wintering localities, and flowering times of many species in North America and Europe.
Here’s a link to one of the original papers by Terry Root, who was a fellow graduate with me at the University of Colorado.
A quick search did not turn up any specific scientific studies on American Robin, but several web pages did mention evidence of Robins wintering farther north than previously.