The Vampire Finch is perhaps the most unusual finch in the world, because true to its name - it feeds on blood!
The Vampire Finch is native to the Galapagos Islands, specifically Wolf Island, also known as Isla Wolf. The Vampire Finch is a member of a large group of finches known collectively as Ground Finches. Within the genus Geospiza, which is the scientific name for Ground Finches, there are 13 different species. The Vampire Finch is unique, however, in its dietary preference. The Vampire Finch feeds on the blood of other birds. It primarily feeds on the blood of Masked Boobies and Red Footed Boobies. In order to feed they will peck the skin of the Booby with their very sharp beaks until they draw blood. Curiously their feeding does not appear to harm the Boobies. It is theorized that this behavior evolved from the pecking behavior used to eat parasites that live within the plumage. The Vampire Finch also feeds on Booby eggs, as well as the lubricating fluids released by the Boobies when they lay the eggs. Some Vampire Finches are not strong enough to crack the eggs, this is particularly true of young Vampire Finches. But these are very intelligent birds, and many will roll the eggs until they fall and crack. These birds appear to be experts at stealing the eggs of inexperienced Boobies that may be laying for the first time.
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.
The Vampire Finch is highly endangered in the wild. It is interesting to note that the Vampire Finch, along with the other finches of the Galapagos are often collectively referred to as Darwin's Finches, since the different adaptations of these finches were used by Darwin in support of his theory of evolution.