A systematic review of avian response to urbanization in China: Research trends, current insights, and future directions

Urbanization is one of the most extreme forms of land-use alteration that is advancing across the world with unprecedented speed. As the largest developing country, China has developed a unique path through its high speed and large scale of urbanization, offering valuable research opportunities for avian ecology. However, a comprehensive review on how birds respond to urbanization in China is still lacking. Here, we systematically reviewed 274 studies published from 1962 to 2024 to determine the research trends, current insights, and future directions of avian response to urbanization in China. We synthesized research trends across four core avian response dimensions to urbanization—diversity, behavior, physiology, and life-history—and their applications in conservation strategy design. The number of publications in avian response to urbanization in China increased annually, and it is influenced by China's developing policies of urbanization. The results also showed an unbalanced geographical pattern of the publications, as the research preferences are relatively prevalent in the developed areas of eastern China. In contrast, there are insufficient studies in the emerging urbanizing areas in the western and northeastern China. Regarding the research contents, most existing studies are focusing on the patterns of bird diversity, while there are few studies on the underlying mechanisms, such as physiological adjustments and life-history strategies. In addition, passerines are the most frequent ones among the studied species. Integrating multidimensional urbanization indices and citizen science data are gradually becoming a new trend in recent years. Our study emphasizes that future studies should pay more attention to the response mechanism of birds in urbanizing processes, multidimensional and interdisciplinary studies, and the transformation of the research results into conservation practices.