Great tits may be adapting to backyard bird feeders

A new study shows that backyard bird feeders in the UK may be responsible for beak evolution in great tits.
By Jose Jefferies | Oct 23, 2017
British bird feeders may be causing UK great tits to evolve longer beaks than ones from other European countries, astudy published in the journal Science reports.

The new research comes from a team of European scientists who used a combination of genetic and historical data to discover the genetic differences between UK and Dutch great tits. This allowed them to pinpoint why some species have longer beaks than others.

Scientists first analyzed the odd trend while conducting a long-term study on populations of great tits in Wytham Woods, Oosterhout, and Veluwe.

In the research, they screened the DNA of over 3000 birds.That revealed the specific gene sequences that evolved in British birds were found to closely match human genes known to help determine face shape.

In addition, the group also tracked different tits to see how much time they spent at automated feeders. That showed the birds with variants for longer beaks visited feeders more often than those without such variation.

"Between the 1970s and the present day, beak length has got longer among the British birds," said study co-author Jon Slate, a professor at the University of Sheffield, according to Phys.org. "That's a really short time period in which to see this sort of difference emerging. We now know that this increase in beak length, and the difference in beak length between birds in Britain and mainland Europe, is down to genes that have evolved by natural selection."

UK citizens spend roughly twice as much on bird seed and birdfeeders as mainland Europe. That difference first began at the start of the 20th century, and has steadily grown over time. While the team is not sure if feeders are the cause of the differences in beak length, it seems like a reasonable explanation. Longer beaks make it easier to get food from inside a container, which would make having extra length a distinct advantage.

"What we can't say is that [bird feeders] are definitely causing the difference between these two populations," said Lewis Spurgin, an evolutionary biologist at the University of East Anglia in the United Kingdom, according to National Geographic. "But the correlation is intriguing, for sure."

Scientists plan to follow up on the study by analyzing DNA samples from great tit populations across Europe. They hope this will give them a better idea of the process and reveal if human-caused anatomical changes show up in any other population.

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