Environmental constraints can explain clutch size differences between urban and forest blue tits: Insights from an egg removal experiment.

ABSTRACT: Urban environments present novel ecological challenges to wild species. In birds, urban populations generally exhibit reduced clutch sizes compared to forest populations. However, whether smaller urban clutches are adaptive or a result of environmental constraints is unclear. To investigate these two hypotheses, we quantified the ability of urban and non-urban blue tits (Cyanistes caeruleus) to lay new eggs after an experimental manipulation aimed to increase egg production. We removed the first four eggs laid by urban and forest birds to test their ability to produce new eggs. If the urban environment imposes constraints on egg production, we predicted that urban birds would not lay new eggs. If the small clutches of urban birds are an adaptive response, we predicted they would lay new eg

SUBMITTER: Pitt MD 

PROVIDER: S-EPMC11880655 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature