You know why ivern has 60% win rate?
Because he can counter jungle SO EASY. 1 level goes blue or red , uses passive + smite = level 2 and good bye ! you let your opponent behind , by getting his buffs .
Also when he clears a buff , you can get the buff too !! So, pretty much even if he is a bad jungler (no ganks) you can get the buffs, and have something as an advantage for you . and that leads you to play better ,and eventually an ivern jungler wins .