"Vocal performance was thought to be a static characteristicset once a song is learned," DuBois said. "Our results are the first to show that songbirds can modulate vocal performance, when it is important to do so."
Theoretically, only males with better genes, or that are in better condition, should be able to produce high performance songs. However, the study found that males are able to increase their vocal performance when challenged by a competitor, explained Bill Searcy, Maytag professor of Ornithology in the UM College of Arts and Science and co-author of the study.
"Even in the case of signals whose properties are physically constrained to reflect an individual's abilities, animals exaggerate their signals as much as they can, during critical situations," Searcy said.
The slow trills of the Swamp Sparrows can be heard during spring and summer across the Eastern and Central North American wetlands. This small songbird with a grey face and reddish wings defends his territory and attracts a mate usually by singing from a raised perch in a brushy swamp.
Results from research on birdsong can be extrapolated to other areas of study, including the evolution of communication, and animal cognition, explained Steve Nowicki, Duke University professor, dean of Undergraduate Education and co-author of the study.
"By understanding what animals do in their natural environment, we get a glimpse of what their brains can do," said Nowicki, "In a broader sense, we can make assumptions about the way the animal brain develops to support a complex communication system."
|Contact: Marie Guma-Diaz|
University of Miami