I am ready to get myself a big South American Anteater, or an aardvark, to keep in the yard to eat up our fire ants.
I have offered each type of bird in my yard, the chickens, guineas, & ducks, a handsome cash incentive
and central A/C installed in their coop IF they would begin to eat up our fire ants. So far, sadly, there have been no takers.
I know some folks swear by the success of the DE, but I've been too cheap to toss that expensive stuff around in the quantities needed to rid the yard of fire ants. Instead, I sprinkle 5% Sevin Dust on & around the mounds I find. It kills the ants and I don't think it's too bad for the birds, you use that same stuff to dust them for mites.
Since I've declared War On Ants, I also spray some more aggressive mounds with bug spray. I use a concentrate I can dilute in a spray bottle, and blast in & around the mounds. I've seen my birds pecking up the larvae right after I've sprayed with no ill effect, but don't take my word for it.
Try to do something to the mounds when they're small & new. Good luck in your war effort!