WASHINGTON?Before taking off each fall for warmer climates, migratory birds consume huge amounts of the most nutritious berries loaded with antioxidants essential for human health, a study has found.
The birds' choice for berries containing the most healthful substances may help improve their fitness for their long and stressful journey, the study's authors said Wednesday as they presented their paper at the American Chemical Society national meeting in San Francisco.
"We know that a diet rich in antioxidants, like those found in fruits and vegetables, is good for human health," study leader Navindra Seeram of the University of Rhode Island said in a statement.
"As a chemist, I think it's fascinating to learn that migratory birds also seek out foods that are richest in antioxidants."
Seeram and his colleagues collected samples of 12 common berries consumed by migratory birds from tiny Block Island, Rhode Island, an important stop for migratory birds as they head along the Atlantic Flyway.
The scientists measured levels of antioxidants and plant pigments in berries at the peak of ripeness, including arrowwood, winterberry, bayberry, chokeberry and elderberry.
They found that birds favored the arrowwood fruits, which had the highest levels of antioxidants and plant pigments -- 150 percent more antioxidants and 650 percent more pigments than the average of all other berries combined.
Some migratory birds consume up to triple their body weight in berries per day -- equivalent to a human swallowing over 300 pounds (136 kilograms) of food each day -- during autumn migration.
Scientists have previously found that some migratory birds seem to favor darkly colored, deeply pigmented fruits, possibly linked to higher antioxidant levels in darker fruits.
"These disease-fighting antioxidants may help the birds combat stress and inflammation that they experience during long flights," Seeram said.
But he noted that his study provides further evidence that fruiting plants co-evolved with birds to ensure plant seeds would be dispersed widely.
"The smartest birds and the best berries seem to go hand-in-hand," he said. "They need each other."