Buffalo, buffalos and buffaloes

Which plural form of the noun "buffalo" is more common in American English: buffalo, buffalos or buffaloes?

Or would you say they are all equally common and the use of a particular form depends on the speaker's preferences?

These Google ngrams for ten buffalo / ten buffalos / ten buffaloes / a hundred buffalo / a hundred buffalos / a hundred buffaloes would indicate that the invariant plural far outperforms 'buffaloes' in the popularity stakes, with 'buffalos' very rarely used: