I'm worried helicopters have been in my neighborhood lately!?

So I live in the Austin, Texas area. And there was a bunch of helicopters blinking green and red, around my neighborhood. I thought it was a terrorist attack lol! no police cars, no ambulance, NOTHING. just a bunch of loud helicopters flying around the austin area, i counted and i saw exactly 13 last night. is something wrong? i turned on the TV and nothing was upp. help?