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Video: En garde! Hummingbirds sword fight with their bills

The long-billed hermit hummingbird’s (Phaethornis longirostris) eponymous beak is ideal for slurping nectar deep within flowers, but a new study shows that males have evolved particularly pointy appendages for the purpose of piercing opponents. In less alliterative terms, male hummingbirds are using their bills to sword fight, often stabbing their rivals in the throat, researchers reported online on 18 October in Behavioral Ecology. By observing juvenile long-billed hermits, scientists were able to observe these behaviors and also measure the gender-specific differences in beak shape that arise as the birds mature. Like Darwin’s famed finches, hummingbird beaks probably evolved through natural selection to help the animals eat from elongated flowers, but for the males it seems there’s an added sexual selection pressure that has slowly sculpted bills to be stiffer, sharper tools for war. It’s a war worth fighting for the males; defending more territory gives them more space to court and impress females.