Did barn swallows evolve thanks to humans?

[Cara J]

What would a barn swallow be without barns? According to recent research, maybe nothing at all. After studying the birds’ DNA, researchers believe it may be impossible to separate barn swallows’ evolution from the human landscape in which they evolved. “It’s an example of humans really profoundly affecting nature and wild populations,” said Chris Smith, lead author of the study in Molecular Biology. After studying the birds’ genome, researchers at the University of Colorado, Boulder believe that the barn swallows’ evolution is tied to human presence. “We probably indirectly affect all species on earth, but this is a drastic example of humans shaping biodiversity on earth,” said Smith, a graduate student in ecology and evolutionary biology and the Interdisciplinary Quantitative Biology program at the University of Colorado. Barn swallows (Hirundo rustica) exist across the Northern Hemisphere. Their characteristic mud cup nests are not just a common sight on the sides of buildings and bridges — they’re rarely found on anything but human structures. That had researchers wondering how much of a role humans and their buildings may have played in the birds’ evolution. “Barn swallows nest on human structures almost exclusively,” Smith said. “We know their ecology is tied to [...]

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