natural fermentation, is it safe

[Chevystairs]

i have some bags of berries that my wife left outside in ziplocks. they smell like they've fermented themselves. i've seen the birds eat old berries off the tree and they seem to get a good buzz going.
so my question is could i use berries, fruits that have fermented naturally and distill them. my worry would be maybe botchalism, or some other poison created. or maybe it would just taste bad, bad in bad out kinda thing.
ps. i have thrown them in a bucket with some sugar and yeast just to see what would happen.