Well, the vampire finch at first glance seems like another ordinary finch, Right? However, the name gives away the most unusual behavior of this bird – it eats blood.
And not just any blood, the specific blood of the Nazca and Blue-footed boobies. (I wonder, why only these birds?) People believe that the boobies willingly let them drink the blood because it rids them of parasites. Maybe they only choose these birds because they have special parasites that are tasty for them.
Well, this is how they drink the blood.
1. They peck a hole through the boobies’ feathers
2. They drink the blood from that area
That seems pretty simple for this bird. However, it supplements this strange diet with a more finch-like diet. It drinks the nectar of the Galapagos prickly pear (Opuntia echios gigantea).
When the 19th century naturalist Charles Darwin (1809-1882) visited the Galapagos Islands, he discovered 15 different species of finches. The vampire finch was among them. From what he discovered, each one of the finches had evolved to fill a different niche in all the islands. Some were blood-eaters (Vampire finch), nut-crackers (Large ground finch), and grub-catchers (Woodpecker finch).
Despite the name, these birds are not finches. They are called finches because after Charles Darwin brought the specimens to Europe, the ornithologist John Gould misidentified them as common, or true finches.
The ancestors of the tribe Geospinizi (many people group all these finches into their own little group) are probably Eurasian Rose finches that got blown over from Russia thousands of years ago.
The descendents of these rose finches soon adapted to the environment. When they got to the Galapagos, it was easy to do this because there was such a plentiful bounty of food.