Female barn swallows continue to “hunt for love” even when they are in a relationship. They are not seeking a partner who is a good provider or loyal mate; instead, they prefer the most attractive males, according to a research team at Cornell University, New York.
“The bad news for the male swallows is that the game of romantic pursuit never truly ends,” said Rebecca Safran, the head of the research team. “This is something that most humans do as well – considering how much time and money to invest in appearance and social status, even when a stable relationship has long been established,” she added.
For barn swallows, scientifically known as Hirundo rustica erythrogaster, good looks mean a beautiful red chest and belly. If a male’s chest is not as dark as that of other males, females are likely to secretly seek out a “lover.” Some unfortunate males may even end up raising a brood of chicks fathered by a rival.
In the experiment, Safran and her colleagues observed 30 pairs of barn swallows that mated and laid eggs. They then removed the eggs so that the birds could mate again, and checked the eggs to identify their parents. Before the females chose a second mate, Safran took pictures of the males and marked their necks, chests, and bellies with red paint, then left them in a natural setting or used a transparent marker to account for the influence of scent or other factors.
Afterward, they allowed the swallow pairs to reproduce again and tested the DNA of the chicks. The results showed that all female swallows still appeared to pair up with their original mates but “strayed” with other males. Males with prominent red markings fathered more chicks than during their first pairing. Those with unchanged coloration fathered the same number or fewer chicks compared to the previous brood.
Experts in ornithology believe that feather color reflects the overall health of the birds and their offspring. For females, these markings become indicators of whom they choose to mate with.
T. An (according to Reuters)
