Grackle flocks=Spring

So this week I've been seeing the Common Grackle flocks moving through the area--one of the earliest bird signs of Spring in the Mid-Atlantic States. Of course, birds have been singing for months now, especially the cavity nesters, checking out territories. And Mourning Doves have been cooing since January, and Great-horned Owls are on nests. There may not be any leaves on the trees, or flowers out yet, but the birds know--Spring has sprung!