Vampire Finches Thrive On The Blood Of Other Birds
The Galapagos Islands: evolution's playground, and home to some of the most fascinating creatures in the world, including one very Goth finch. According to an interview that Wired conducted with evolutionary ecologist Ken Petren, the vampire finch, a subspecies of the sharp-beaked ground finch, earned its title by drinking the blood of other birds, specifically that of the blue-footed booby. "On this island they really seem to be purposefully going up to a booby chick in the nest, and they peck at the base of their tail where they have oil glands, and they make it bleed and they drink the blood," Petren said.
The vampire finch isn't doing this to be mean, nor is it trying to emulate Nosferatu or Robert Smith, but because its preferred diet of seeds and insects isn't always readily available on the drought-prone Wolf Island. According to an article on GalapagosIslands.com, the blood-drawing may also be evolutionary, coming about when the finches were doing the seabirds a solid and cleaning parasites out of their feathers; the finches would sometimes nick the booby's skin, and discovered that blood is not only tasty, but nutritious. And during those stretches where insects are scarce, a finch has to do what a finch has to do. Don't judge.
Boobies Are, Apparently, Very Tolerant
Assistant Professor of Ecology and Evolution Jaime Chaves elaborated in The Conversation: "Eventually however, the removal of parasites led to open skin lesions on the boobies, allowing the finches to consume blood. The finches even learned to pierce skin at the base of young feathers to access the blood directly, no longer needing the insect parasites anymore. Thus, the finches capitalized on an alternative food resource, blood from the boobies, and earned themselves the nickname 'vampire finches.'"
And don't worry; though watching (via National Geographic on YouTube) the fiendish finches getting their blood snack on looks painful to the poor boobies, it's really more of a nuisance than anything. "We observed scores of vampire finches clamouring all over the backs, tails, and wings of boobies, opening up substantial wounds with their sharp beaks, and drinking their fill of blood," reports The Conversation. "Interestingly, the finches seem to act like a true parasite, inflicting enough damage to secure a meal without excessively harming the host." It's kind of like humans a mosquitoes. Although the boobies "can tolerate the finches, the small bloodsuckers are a nuisance that the boobies do try to get rid of."
A Little Egg To Go With Your Blood?
Going back to that article in Wired, crowds of vampire finches gather when the blood starts to flow, which, okay, yes, that is a little creepy. In addition to blood, eggs draw the finch crowd, too. Petren observed, "The birds will put their head down on the ground and lift their feet up and push eggs so the eggs will roll off a cliff and break. And then they go hovering in and sip up all the yolk... As you get one that's sitting there trying to roll an egg, all of the other ones come around and they're watching, and they're watching, and they're waiting in this little crowd of vampires all waiting for the goods to be spilled. And each one will take his turn and go in there and try to roll the egg."
Petren also informed Wired that the vampire finches even enjoy a little ground vomit. Very punk rock.
Oh, nature! Never a dull moment with you.