Investigating the effects of local climate zones on the breeding phenology of urban bird species in Gothenburg, Sweden

The impacts of climate change and urbanization on phenology are well-documented. Specifically, the phenological asynchrony or mismatch between birds’ breeding and the timing of vegetation green-up can lead to lower survival rates of the offspring, potentially contributing to population declines over time. Since birds provide essential ecosystem services, such as pollination, seed dispersal, pest control, and cultural benefits, shifts in their phenology could have broader ecological and social consequences. While previous research has explored phenological differences between urban birds and their rural counterparts (urban-rural variations), studies examining intra-urban phenological variations driven by different local morphological and climate conditions are lacking. To bridge this gap, we explored the spatial and temporal variations in the singing phenology—the most evident aspect of avian breeding behavior—of 61 bird species across 30 sites representing different local climate zones (LCZs) in central Gothenburg, Sweden. The bird species data was systematically collected across these sites using 10,691 hours of passive audio recordings during spring 2024, and the LCZs were manually classified based on site metadata. Preliminary findings show notable variations among the study sites/LCZs in the timing (start/end) and duration of the singing period for certain species, such as the Eurasian blue tit, Eurasian tree sparrow, and the common starling. This highlights the importance and potential role of urban planning and design, through interventions in urban form and function, in shaping local climate conditions and, consequently, influencing avian dynamics in cities.