City life takes its toll.
According to a new study published in the journal Biology Letters, birds living in an urban environment are at greater risk of dying young than those living in the country.
Researchers from Lund University in Sweden took great tit chicks born in the city and placed them in the care of rural foster parents. They then sent chicks of country-dwelling parents to live with rural foster parents.
After 15 days, the team collected blood samples to measure the length of each chick’s telomeres — the protective caps that shield chromosome ends from getting damaged. Because telomeres shorten as an organism ages, telomere length can be used as a biomarker of life expectancy.
Regardless of where they were born, the birds that were raised in the city had telomeres 11 percent shorter than those of birds growing up in the country.
“Previous studies have shown that genetics have an effect on the telomere length in individual birds,” said study lead author Pablo Salmón in a press release. “What we’re showing now is that growing up in a stressful environment has even more of an impact.”
The authors suggest that increased stress due to city pollution, which can cause DNA damage, could be to blame for the rapid cellular aging seen in urban great tit chicks.
“Although there are advantages to living in cities, such as the access to food, they seem to be outweighed by the disadvantages, such as stress — at least in terms of how quickly the cells of the great tits age,” Salmón said.
According to the researchers, their results indicate the need for further studies on the impacts that urbanisation has on wildlife. Salmón also notes that the findings “raise questions concerning the aging of other animals affected by urbanisation, and humans for that matter.”
You might also like: If You Want to Protect Nature, Stay Away: The Hidden Dangers of Ecotourism