Robin in the rain

I've never thought of robins as particularly gregarious birds, but in the midst of all the storms we've had this last week, we discovered our backyard was hosting quite the flock of robins! The giant backyard privet (which I ordinarily despise) was filled with what, at least from the window, looked like literally dozens of robins, as they flitted between our yard and our neighbor's, and down to the lawn to look for worms. Indeed, looking out the window I saw that the neighbor's tree was full of robins too:

I have no explanation for the strange occurrence (but if you do let me know). All I know is that it made for a great morning's entertainment while stuck in the house. Cassidy and I spent a long time checking out the birds (or "cah"s as Cassidy calls them, thanks to the fact that usually most of the birds around our house are crows) from all the vantage points on the back and side of the house: