I’ve read that story, but didn’t remember the name or author. 
I vote for the passenger pigeon as well. Also, the pygmy mammoth of California’s Channel Islands. That would increase visitor numbers to the islands!
No one wants to bring back our ancestors? The Neanderthal, or earlier?
Oh, I’m sure he could make an offer nobody could refuse.
Nope, I wouldn’t.
First: they would end up as slaves. Sex slaves, perhaps. Probably, even.
Second: the Neanderthal is not our ancestor. It is a parallel evolutionary dead end, a failure. No, max. 3% of some modern Europeans’ genome is not enough in my book to call them ancestors. YMMV, of course. Oh, and point one, just above, still holds. Where did those 3% come to be?
Third: earlier? Yes, they might be our ancestors. But what is an ancestor if not a predecessor. Do we need to be evolutionary led to us again? What makes you think this time it would be better?
You might as well try to breed an Übermensch. Bad unintended consequences all around, I see. Better not mess with the human genome is my advice.
The Pigeon is sadly impossible, and people would certainly notice the Mammoth.
Doesnt fit the OP, and not a good idea-
I could make so many political jokes with this…but I’m not going to.
Back to the OP: The quagga, which apparently is already the subject of a reintroduction project.
Regarding the dodo bird, I just learned recently that it was part of the same family as pigeons. And yes, it would be cool to bring them back.
The not a good idea I agree with. Although Homo florisiensis (AKA the “hobbit”) might still fit the criteria of the OP. One could say they were discovered in some less explored area in one of the lesser explored islands around Indonesia.
And … Squab is delicious. In addition to their valuable ecological role, i think they might make a terrific domestic animal. The fact that they aren’t afraid of people ought to mean it would be fairly easy to raise then humanely, too.
Yeah, subspecies should be easier.
That was kind of my point with my post, I think they would have made an excellent barn yard fowl, easier to raise than turkeys or chickens with more meat output. Sort of like geese, they just would waddle around the property and the food bowel. And of course, crapping all over the place.
I don’t see them upsetting the ecological balance.
The issues with Dodos are-
Mauritania does not have a good record there- 12+ other species went extinct, and they recently “culled” thousands of endangered Flying foxes, due to the possibility of damage to fruit crops. Not to mention due to rats, pigs and other introduced animals, the Dodo wouldnt last a year- unless one of the small islands was cleared of all mammal species (hard to do) and rigorously protected (not likely).
Next- they werent afraid of humans being as they had no relationship with mammals- same as the Galapagos Iguana. But that would wear off quickly.
Then, the Dodo apparently tasted nasty. Starving sailors had no issue with it (but they would eat rats and hardtack full of bugs), but the Dutch who tired it called it nauseating.
Scientists are unsure about the so-called “Dodo tree”- if it really needed Dodos to germinate.
Finally, it would be really obvious someone brought them back- the Dodo went extinct some 400 years ago, so it doesnt fit the OP.
Mind you, cloning a few for some safe enclave so we can see how they really looked and ac ted would be interesting.