Galápagos finches are famous for their beaks. Years of evolution have specialised their schnozzes for different purposes – the formidable bill of the large ground finch cracks nuts, the woodpecker finch’s tapered beak drills into trees, and so on.
And what of the elegantly curved, sharply pointed beak of the vampire finch? Well.
Vampire ground finches (Geospiza septentrionalis) live way out on Wolf and Darwin Islands, the most far-flung of the Galápagos. (Darwin himself stuck to a more centralised area and never encountered them.) It can be hard to find food there, especially during the dry season, which runs from July through December.
So a finch may slake his hunger and thirst by sticking his beak into a Nazca or red-footed booby. The finch pecks the much larger bird – usually just under the wing – waits for the blood to flow, and slurps it down. Other finches often wait around to tap in, or maybe to pick up some pointers.
Many small birds peck bugs and parasites off larger animals. Researchers think the ancestors of the vampire finch may have been among this group, and that the species’ thirst for blood arose when a bug-pecker dug in a little too hard.
This theory may help explain why boobies generally ignore their attackers, even as red stains bloom over their snow-white feathers. Although they may just be outnumbered – observers have noticed that a booby who tries to bat away a finch quickly gets swarmed.
In the wet season, vampire finches scratch for seeds and insects and sip nectar from cactus flowers. They’ll also eat guano, seabird-regurgitated fish, and booby eggs, which they work together to roll off cliffs.
This article is excerpted from Atlas Obscura: Wild Life: An Explorer’s Guide to the World’s Living Wonders by Joshua Foer & Cara Giaimo. Workman Publishing, 2024.
Main image: a nazca booby snapping at a vampire finch/Atlas Obscura
More fascinating stories from the world of wildlife
- Bison snot holds the American prairie together. Here's how, according to an ecosystem expert
- Mummified seals are appearing in Antarctica’s ice deserts. Explorers just found tracks leading to one of the bodies
- There’s a bizarre animal in Oregon that looks and smells like a sock – and scientists are feeding it sardines. Here's why
- Scientists just collected 11 petri dishes of dolphin breath – and found something very worrying