Variation in Avian Nest Predation Rates under Urbanization: A Multi-City Comparison across China

The alteration of predator–prey interactions (interspecific interactions) remains one of the main mechanisms underlying the loss of urban biodiversity—which can impose varying levels of predation pressure on urban birds. Previous reports on the effects of nest height on predation rates remain inconsistent, with some stating that low nests experience higher predation rates than high nests, while others stating that nest height has no significant effect on nest predation rates. To address this knowledge gap, we adopted a multi-city comparative design across a broad latitudinal range to examine the effects of urbanization on avian nest predation rates. Four cities in China with significant latitudinal differences (Changchun, Beijing, Hangzhou, and Haikou) were chosen as study sites, and standardized artificial nest experiments were conducted in each city. Three habitat types (urban green space, urban road, and suburban green space) were chosen in each city, and two nest types (ground nests and tree nests) were placed in each habitat type to compare nest predation rates across different habitat types and nest types. Our findings showed that nest height did not significantly impact nest predation rates, while the effect of urbanization on these rates exhibited considerable variation among cities. The findings highlight the complex relationship between urbanization and nest predation rates, warranting future studies to explore key drivers modulating this relationship.