The Passenger Pigeon roosted in geographically limited areas for their mating season, and the hunters just showed up for it and gunned them down, selling the carcasses for use as squab in east coast hotels and other restaurants. Regardless, it was a d***ed pigeon.
There’s a long shot at reviving a genetically narrow version of it, from old feather pillows and museum type specimens, but again, it was a d***ed pigeon.
There’s at least two active programs to revive the full-sized mammoths. Pygmy mammoths were still around in very small numbers (the constraint was the food supply) a mere 2000 years ago.
I’d like to see the revival of the auroch, but as in all these examples, I can live without it.
BTW, note that this is a TEDx talk, given by a lawyer, not a scientist.