Ornithology, robins in the winter

I've known for a long time that American robins in this part of the world contrary to popular belief, (and their scientific name: Turdus migratoris) don't migrate but actually lay low during the winter. For this reason, they are not normally seen in these parts at this time of the year.

Not so in Millennium Park where for the past several days I've seen scads of them. Further testimony to the success of M.P. I suppose. It even brings the robins out of hibernation.

These sightings will make my annual first robin as a harbinger of spring sighting somewhat of a letdown.