Many birds – including finches and sparrows – can see ultraviolet (UV) light; a new study reveals two essential adaptions that enabled these birds to expand their vision into the UV range and see a visual world hidden to humans.

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Many birds – including finches and sparrows – can see ultraviolet (UV) light; a new study reveals two essential adaptions that enabled these birds to expand their vision into the UV range and see a visual world hidden to humans.