[Research advances in the effects of urbanization on birds based on bibliometrics]

Birds are key indicator taxa for assessing urban ecosystems condition, as their diversity, distributional patterns, and community structure reflect environmental quality in urban settings. To synthesize the research progress of urban birds, we employed bibliometric analysis and inductive synthesis to analyze the distribution of research hotspots, evolutionary trajectories, and thematic keyword categories, based on literature indexed in CNKI and the Web of Science Core Collection over the past two decades. We found that research in both contexts shares a common focus on the impacts of urbanization on bird communities and on biodiversity conservation. Research in China exhibits a policy-driven orientation toward conservation planning practice, whereas international research emphasize individual- to population-level behavioral and physiological response mechanisms, with comparatively more mature frameworks. Current research on urban birds focus on five main aspects: 1) the effects of urbanization on bird community composition and structure; 2) the influence of urban green space configuration and vegetation attributes on birds; 3) behavior and survival adaptations under urbanization; 4) the effects of urban environments on morphology and physiology; and 5) planning of urban ecological parks grounded in bird conservation. Future works should highlight the significance of ecosystem services provided by urban birds, advance conservation from multiple dimensions, and enhance both quality and efficiency through integrating theory with practice.