Knowledge Gaps Remaining in the Spatial Analysis of Bird Banding Data: a Review, Focusing on Use of Japanese Data

Bird banding has been widely used for more than a century to study the large-scale spatial movements of birds. Continent-wide and transcontinental movements of birds, such as dispersal and seasonal migration, have been revealed by ring recoveries that link departure and destination locations. However, movement inferences have been mostly qualitative, and many limitations and biases have impeded accurate and detailed inferences of movement patterns. Banding data, nevertheless, provides the largest data set for bird movement studies, thus the development of statistical methods to utilize them effectively is the active frontier of research. In this review, we summarize briefly emerging opportunities for quantitative inferences of bird movements from banding data and indicate how they have improved our understanding of bird movements. Banding data is powerful when integrated with external data sources (e.g., direct tracking data), and prove informative for macroecological and macroevolutionary studies. However, such integrated practices have been limited to studies of European and American avian species. A systematic review of the use of Japanese banding data in scientific publications, shows that it is used significantly less often than that of European or American data, and publications were often invisible to the international scientific community. This poor visibility and low rate of usage is likely due to the relative inaccessibility of the data, as most of it is published in Japanese, and the relatively small number of ring recoveries, which makes the data less attractive. We argue that such an inter-flyway disparity may have created severe knowledge gaps in avian movement studies, including incorrect predictions of avian responses to future climate change and less effective conservation actions in Asia. The Japanese data represents Asia's largest banding and recovery archive, and future work needs to effectively integrate it into cutting-edge statistical frameworks to expand the field of bird movement studies.