Backyard feeders changed the shape of hummingbird beaks, scientists say : NPR

A recent study has shown that Anna’s Hummingbirds in the western United States are not only adapting to human influences on their habitat but thriving in the process.

Research published in the Global Change Biology journal revealed that the use of hummingbird feeders has led to changes in the birds’ beak size and shape, allowing them to access more nectar efficiently. Additionally, the birds have expanded their range from southern California to as far north as Canada.

“The bills of the hummingbirds have become longer and more slender, enabling them to extract more nectar from the feeders,” explained Alejandro Rico-Guevara, a biology professor at the University of Washington and the study’s senior author.

The study, conducted with 16 collaborators from 12 different institutions, also observed that male hummingbirds developed pointier beaks over time to compete with other males at the feeders. The birds have migrated further north, adapting to cooler temperatures as they follow the increased availability of bird feeders. The study also highlighted the impact of eucalyptus forests, introduced to California from Australia in the 1900s, as another food source for the hummingbirds.

Hummingbird Evolution

By analyzing newspaper archives, census data, and museum specimens of Anna’s Hummingbirds dating back to the 1800s, the researchers documented the physical changes in the birds over approximately 10 generations. This evidence displayed the significant impact of human activities on the evolutionary trajectory of the hummingbirds.

Faye Romero, a Ph.D. candidate at the University of Rochester and co-author of the study, emphasized the active role humans play in shaping the organisms around us. She noted that while the hummingbirds are currently adapting, the long-term implications for other species remain uncertain.

Human Influence on Birds