Crane Hawks of Central and South America and African Harrier-Hawks both have legs that bend forward and backward. Each bird’s wonderfully peculiar leg adaptation is completely original — it evolved all on its own — even though the end result is the same. It's a fascinating example of a phenomenon called convergent evolution.More info and transcript at BirdNote.org.Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.  Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.