I find it fascinating that we dont know how they became extinct. I had originally thought it was simply habitat destruction but that hasn't really be proven at all.
Indeed, some thought it was simply farmers plowing fields or stock grazing, but their origin point were mountain valleys so it doesn't seem their demise would have been as rapid as it actually was.
https://www.youtube.com/watch?v=DqyCO1eVC68&t=26m38s