UCLA

Behavioral plasticity is an important mechanism for rapid adaptation to novel environments, including urban ecosystems.. However, whether such plasticity is adaptive, and if plasticity is convergent among urban populations, is poorly understood. We studied an “urban-adapter” species, the dark-eyed junco (Junco hyemalis), to understand the role of nesting plasticity in adapting to city life. We examined 1) whether novel nesting behaviors are adaptive, 2) whether pairs practice informed re-nesting, and 3) whether two urban populations exhibit similar nesting behavior. We monitored 170 junco nests in Los Angeles and compared our results to prior data on 579 nests from San Diego. We found that nests placed in ecologically novel locations increased fitness, and that pairs practiced informed re-nesting. The Los Angeles population more frequently nested off-ground than the San Diego population and exhibited a higher success rate. Our findings suggest that plasticity facilitates adaptation to urban environments.