Bird weirdness

I live in South Texas. Usually, we have tons of red-wing blackbirds in the winter. I have a feeder right outside my window and watch them. This year I have seen NONE, ZERO...until about a week ago when they suddenly showed up in huge numbers. This is doubly strange when you realize that we DON'T have them in the summer. So, WHY are they suddenly showing up in the Spring? Anybody else?

Yeah, everything is "normal"...