Migratory birds' stress cause faster ageing, premature death

New York: Stress experienced by birds as a result of their continent-spanning annual migrations is leading to faster ageing as well as potentially earlier death, a study has found.

Migration lets birds take advantage of abundant food resources at high latitudes during the breeding season while escaping the region's harsh winters. 

However, it's also an enormous undertaking, and the benefits that birds gain from it come with a cost, the researchers said. 

The findings revealed that telomeres -- the structures on the ends of chromosomes that shorten with age -- are shorter in migratory birds than in their non-migratory counterparts.

The team compared the telomeres of migratory and resident birds from the same species -- Dark-eyed Junco. 

They found that the migrants had significantly shorter telomeres than birds that stayed put year-round, suggesting that the migratory birds were aging at a faster rate and that the stress of a migratory lifestyle may actually shorten birds' lifespans.

"Whenever our cells divide, we lose a little bit of DNA on the ends of our chromosomes, and telomeres are simply non-coding regions that act as protective caps," said Carolyn Bauer from North Dakota State University.

"Once they reach a certain threshold of shortness, the cell dies," Bauer said adding, "exposure to stress can also make telomeres shorten faster."

For the study, published in the journal The Auk: Ornithological Advances, the team collected blood samples from 11 migratory and 21 resident juncos in Virginia, using only first-year birds to ensure that any telomere differences were not simply due to age.