Aug. 21, 2013 — A new study conducted at the University of Colorado Boulder and involving Cornell University shows the outward appearance of female barn swallows, specifically the hue of their chestnut-colored breast feathers, has an influence on their physiological health.
It has been known that in North American barn swallows, both males and females, those with darker ventral feathers have higher reproductive success than those with lighter colors, said Cornell Senior Research Associate Maren Vitousek, who led the new research while a postdoctoral researcher at CU-Boulder. Although there is evidence that breast feather color is significantly influenced by genetics, melanin-based plumage color like that in barn swallows also has been tied to social status and even to circulating testosterone, she said.
The new study showed that both naturally darker barn swallow females and those with artificially darkened breast feathers also had lower levels of oxidative damage, which could ultimately make the birds healthier. Oxidative stress results when the production of harmful metabolites known as free radicals exceeds antioxidant defenses in the birds, which can lead to DNA, protein and fat damage in the birds, said Vitousek.
"Intriguingly, females whose feathers were darkened to resemble 'attractive' birds rapidly adopted the physiological state of darker birds, decreasing their level of oxidative damage," said Vitousek. "These results suggest the appearance of an individual may be an under-appreciated driver of physiological health."