A new University of Colorado at Boulder study indicates North American barn swallows outperform their peers in reproduction -- the "currency" of evolutionary change -- by maintaining a positive balance of antioxidants commonly sold in health food stores.
The study is the first to track concentrations of carotenoids, which are naturally occurring plant pigments, in a wild bird or animal species over the course of the grueling breeding season. Carotenoids can offer the benefits associated with over-the-counter nutritional supplements that protect cells from free radical damage, said CU-Boulder Assistant Professor Rebecca Safran.
Since American barn swallows migrate thousands of miles to their breeding grounds annually and immediately commence courtship, nesting and reproductive activities, many lose significant amounts of weight and become physiologically compromised during the intense spring activities, said Safran, lead study author. But the new study indicates some individuals can bear such costs better than others, she said.
While other studies have looked at carotenoid levels in captive birds at a single point in time, the new study is the first to monitor carotenoids within wild individuals as they feed, mate, nest, and rear young, said Safran of CU-Boulder's ecology and evolutionary biology department. "Our results indicate the concentrations of these molecules are highly variable within individuals over time," she said. "The season-long balance, rather than a sample at a single point in time, indicates which birds are the top performers as parents and mates."
A paper on the subject appears in the Feb. 25 issue of PLoS One, a journal of the Public Library of Science. Co-authors on the study included Arizona State University Associate Professor Kevin McGraw, CU-Boulder doctoral students Matthew Wilkins and Joanna Hubbard and project volunteer Julie Marling.
"By monitoring wild populations of ba
|Contact: Rebecca Safran|
University of Colorado at Boulder