Dunno how far south or west you are in "South Texas". Unless yoo're on out toward the western brush country part, odds are they're bob whites.
They'll spook from a tractor, but they're territorial little critters, and will return home.
The Parks & Wildlife people have all manner of literature about quail.
I have a solar-powered clock feeder near my house, feeding hen scratch once a day. Not a lot, but it keeps the quail and doves around.
The biggest enemy of quail is the feral housecat. I shoot any I see.
If you have the time, inclination and patience, you can train the little buggers to come when you call. Just do the "Chick, chick, chick..." thing at the same time every day, scattering out some grain. Start with just a handful, until they find it and start to associate your calling with the food. Takes maybe a month or so. If you work at it, you can sit in a chair and they'll keep coming closer. I've gotten blues to run around under my chair, happily pecking the goodies.
Welfare folks are everywhere...
, Art
Art