The buffalo mostly died out from brucellosis and the awful winter of 1876 after 10 years of nearly perfect buffalo weather.
Humans killed about 6-8 million.
I AGREE. I was just going with the meme that God-awful humans without proper gun control were responsible.
I also think the herds were a lot smaller than the awed reports of the time stated.
I think you have your year wrong. Probably 1886, part of a 5 year volcanic winter following the 1883 eruption of Krakatoa. Seventy five% of cattle were lost in 1886. Also several other major volcanoes around that time.
https://blogs.ancestry.com/cm/now-thats-cold-the-worst-7-winters-in-american-history/
https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptions_of_the_19th_century