When examining his specimens on the way to Tahiti, Darwin noted that all of the mockingbirds on Charles Island were of one species, those from Albemarle of another, and those from James and Chatham Islands of a third.
Cando examinou os seus espécimes camiño de Tahití, Darwin decatouse de que todos os mímidos da illa Floreana eran dunha soa especie, os da illa Isabela (illa Albemarle) eran doutra, e os da illa de Santiago (illa James) e illa de San Cristóbal (Chatham) eran dunha terceira especie.