What the hell is with you and DDT? I've already told you: It's been banned since 1971.
Yes, I know it's been banned for yonks, legal elf magic doesn't somehow make it less effective. It does it's job fine, except on some populations of mossies. You can find ceramic jugs of it floating around, as I said. I got the last dregs of a 500ml jug of 5% solution. Kills ants (and everything else) dead, it does.
P.s: The dodo was a successful species, as was the elephant bird (they were seriously huge) in madagascar, but they were too delicious and had too larger need for resources to compete in the presence of humans.
They were stupid enough to not turn tail and run.
Only the biggest/strongest or the smartest shall remain alive.
Yeah generally most larger critters don't automatically fear humans, it takes a while of hunting for the faster ones to naturally fear humans. (Again, with madagascar, various species of lemur being hunted.)