Western harvester ants

Thanks for the ID and the info Goody. I did watch them for a little while. I should watch more carefully to see what stuff they are carrying around.

The harvester ant is capable of stinging but it is much different than the fire ant that you mentioned. They don't behave in quite the same way. They are much more mild mannered and you can approach their nest without setting off a stinging swarm. I think it's a lot of fun to watch harvesters carry food items back to their nest. The species we have in Oklahoma has been on the decline for years, and that's greatly impacting the population of Texas horned lizards, which rely on these ants for food.