Bird feeders have caused a dramatic evolution of California hummingbirds

Beaks have grown longer and larger, and ranges have expanded to follow the feeders

21 May 2025 5:01 AM ET
By Rachel Nuwer



In response to the glut of nectar from hummingbird feeders, Anna’s hummingbirds like these two females in Southern California have evolved longer, larger beaks in a matter of decades.Alamy Stock Photo

Hummingbird feeders are a beloved pastime for millions of backyard birders and a convenient dining spot for the birds. But for the Anna’s hummingbird, a common species in the western United States, feeders have become a major evolutionary force. According to research published this week in Global Change Biology, artificial feeders have allowed the birds to expand their range out of Southern California up to the state’s northern end. They have also driven a transformation of the birds themselves. Over just a few generations, their beaks have dramatically changed in size and shape.

“They seem to be moving where we go and changing quite rapidly to succeed in their new environments,” says co–lead author Nicolas Alexandre, who conducted the work when he was a graduate student at the University of California, Berkeley and is now a geneticist at Colossal Biosciences, a biotechnology company based in Dallas. “We can think of Anna’s hummingbird as a commensal species, similar to pigeons.”

Carleton University animal behaviorist Roslyn Dakin, who wasn’t involved with the study, adds that the new paper beautifully shows “evolution in action.”



It’s unclear when the first hummingbird feeders were developed, but after the first patent appeared in 1947, sales began to soar.U.S. Patent Office

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