robin in Backyard Birds, Feeders and Food Posted February 20, 2021 I have read that robins will gather in large flocks during the winter. Then when breeding season starts , they will break off and look for mates. That is why I think of spring when I start to see single robins or pairs. A look at a range map will show robins all year in the U.S. states. I'm not sure where I heard robins are a sign of spring, but I have heard this for as long as I can remember. I am 58 years old, so it has been quite a while.