Like all thirteen species of ground finch, the Vampire Finch is sexually dimorphic. That is the males are visually distinguishable from the females. Males have black plumage, while females are generally grey with brown streaks across their plumage. All ground finches have short strong beaks, which are used for crushing. The size and shape of these bills are all slightly different between species. Of all the species of ground finch, the Vampire Finch is theorized to be the most closely related to the ancestral finch from which all ground finches evolved.
