Lower Rio Grande Valley Birding Hotline Blog and they had an address for these guys. Should you want to go see them for yourself: go to the corner of 5th and Gardenia in Hidalgo. Drive down 5th a little ways and you'll see a big nest (see below) on a telephone pole on the left side of the road. Wait. They'll be there.
Usually when I go look for something on the Rare Bird Alert, I have to wait around, and maybe I don't get to see it at all. But the birds were nearly exactly at their reported location and it was the easiest rare life bird ever. Here they are: