Bird Behavior Studies Win Award

The brown-headed cowbird has developed a survival strategy that tricks birds of other species into raising the cowbird's offspring. Cowbirds are so-called "brood parasites," a group of birds that substitutes their eggs for those of the foster parents.

For more than 30 years, this behavior has fascinated Steve Rothstein, director of the Museum of Systematics and Ecology at UCSB and professor in the Department of Ecology, Evolution and Marine Biology (EEMB). He recently received the Brewster Award for 2001, the highest honor given by the American Ornithologists' Union, for his "detailed and perceptive contributions to the fields of behavioral ecology, evolution, and conservation of birds."

"Dr. Rothstein has contributed uniquely to ornithology with his stellar research in the behavioral ecology of birds," said Roger Nisbet, chair of EEMB. "His most important work concerns the interactions between parasitic birds and their hosts, in particular the evolution of host defenses to brood parasitism."

The award cited Rothstein's "novel, careful, and elegant experimental studies on parasitic egg rejection behavior. These studies revealed that most songbirds tested could be classified as either acceptors or rejecters of brown-headed cowbird eggs. The lack of intermediate levels of rejection suggested that selection for parasite egg recognition must be very strong in hosts; once the behavioral mechanism needed to recognize and eject parasitic eggs evolved, it would be rapidly fixed in the population."

Recently, Rothstein has contributed to conservation programs involving endangered species that may be impacted by brood parasitism. He has analyzed the role that brown-headed cowbird parasitism plays in population declines and endangerment of North American songbirds, especially Western species such as Bell's vireos and willow flycatchers.

Rothstein's behavioral studies have included brood parasitism in related South American cowbird species and Old World cuckoos, and detailed analyses of population trends, breeding ecology, dispersal, and vocalizations in the brown-headed cowbird.

"His contributions to the study of avian vocal behavior, in particular to our understanding of the behavioral and evolutionary significance of repertoires and dialects, have been exceptional," according to the Brewster's citation.