Exploring Urban Bird Diversity in a Chinese City Using Citizen Science Data: A Case Study in Shanghai

Urban bird diversity plays an important role in sustaining urban biodiversity and ecosystem health. Previous studies often rely on conventional field surveys to investigate bird diversity and focus on micro-scale urban green spaces such as parks and gardens. The emergence of citizen science data has made it possible to examine urban bird diversity at broader city scales. Using citizen science data, this study investigated urban bird diversity at the city scale in Shanghai, China. Based on approximately 390,000 bird observation records collected from China Bird Report Center (CBRC) in Shanghai in 2024, the study analyzed the spatial patterns of bird species richness, species abundance, and reporting-rate richness. Reporting-rate richness estimates the likelihood that different bird species are reported in a given area, helping to mitigate biases in citizen science data. The results showed that Shanghai recorded a total of 2,436,951 individual bird observations and 345 bird species in 2024. Regarding the spatial patterns of species richness and species abundance, central urban areas of Shanghai had relatively high observation point density while suburban ecological spaces also contained concentrated observation points. Species richness and species abundance were higher near waters and green spaces. The high values of reporting-rate richness were not concentrated in a few specific areas, but instead showed a more continuous and widespread spatial distribution. By integrating conventional biodiversity indicators with a reporting-rate-based metric that accounts for observation biases, this study extends citizen science-based urban bird research from local-scale observations to a continuous city-wide assessment. The findings provide spatial evidence to support the implementation of the Shanghai Biodiversity Conservation Strategy and Action Plan (2024–2035), particularly by informing habitat conservation priorities, ecological network enhancement, and biodiversity monitoring in rapidly urbanizing areas.