Dissertation Defense: Ohad Paris--Cardinal Behavior, Ecology

Topic: Ecological and Behavioral Effects on the Reproductive Success of Urban Northern Cardinals

Nest predation is the primary source of reproductive failure for songbirds in most ecological systems. Habitat patches within large metropolitan areas that have been developed for decades often support diverse populations of songbirds, but the factors shaping reproductive success in these habitats are understudied. In this dissertation, I investigated the drivers of nest predation in a common songbird, the northern cardinal (Cardinalis cardinalis), in small urban forest patches. Nest predation varied with spatial factors on multiple scales, and was related to spatio-temporal patterns of habitat selection and female personality. Nest sites were overall spatially biased toward patch edges, but early nesting cardinals preferred habitats away from the edge with low predation risk, and exhibited higher reproductive success than later nesting birds. Cardinals nesting near patch edges faced more intense nest predation pressure, but also exhibited bolder personalities, with bolder nest defense behavior positively associated with nest success. These findings demonstrate that landscape-dependent edge effects on nest predation emerge even among patches within decades-old urbanized areas, and that cardinal behavior plays an important role in generating spatial patterns of nest predation within urban patches.