Look out bats, there’s another winged creature vying for the title of baddest vampire in the sky. Finches—just like the ones Charles Darwin famously studied—also come in a vampiric flavor. And new research, published this month in Philosophical Transactions of the Royal Society B: Biological Sciences, suggest these blood-sucking birds share similar gut bacteria with bats. When times are lean and food is scarce, the finches use their sharp beaks to suck blood from another bird, the Nazca booby. Because blood is lacking in many essential nutrients, the finches have evolved to host the same microbes that help the bats survive on such an extreme diet, The New York Times reports.