Laura Erickson's For the Birds

I’ve never seen this bird nor been in its range, but it has a place in the Guinness Book of World Records:

Sharp-beaked Ground Finch: Most bloodthirsty bird. The world’s most bloodthirsty bird is the vampire finch (Geospiza difficilis septentrionalis) - a subspecies of the sharp-beaked ground finch (Geospiza difficilis)- which only inhabits Wolf Island and Darwin Island in the Galapagos Islands, Ecuador. The vampire finch typically eats seeds, but since 1964 scientists have observed this species pecking large seabirds (mainly the Nazca Booby and Blue-footed Booby) and drinking the blood that seeps from the wound.