| Abstract: | Life history theory and empirical studies suggest that early breeding confers higher reproductive success, but the extent to which this advantage can be generalized to human‐dominated systems and across species is less well understood. We studied the fitness consequences of clutch initiation for 181 female northern cardinals Cardinalis cardinalis and 1228 nests in forests within urban and rural landscapes of Ohio, USA between 2004–2007. Cardinals that bred earlier made significantly more nesting attempts, but cumulative number of young fledged was similar to that of later‐breeding individuals. The expected number of fledglings produced per successful nest was unrelated to date and remained ~1.8 fledglings across the season, despite the fact that nest survival rates improved dramatically as the season progressed. Because the probability of resighting breeding individuals in subsequent years was unrelated to first clutch initiation date, we have no evidence that clutch initiation affected adult survival. The absence of a clear benefit to early breeding appears to be a consequence of high rates of nest predation early in the breeding season. |
