Satellite tracking data reveal the underestimate population size of the ground survey

The population of East Asian geese along migration routes is declining. Accurate understanding of the spatial distribution of wintering geese and estimates of their population numbers are vital for their conservation. Based on satellite tracking data, the migration timing and spatial distribution of geese in Poyang Lake were studied by using time series and home range analysis. We propose a method for estimating goose populations to address the population underestimation in current ground surveys. We found that the utilization intensity of geese is higher within the Protected area than outside, and during the wintering period, spatial overlap in their distributions is evident. This is especially the case in mid-winter, when the overlap area reaches 257.84 km2. There are missing areas in existing ground surveys, resulting in underestimation of the numbers of Greater White-fronted Goose, Bean Goose and Swan Goose by 13,196, 6157 and 3191, respectively. A reevaluation of the numbers using integrated satellite tracking and ground survey data, indicates the high level of importance of Poyang Lake for the protection of East Asian geese, with the numbers of Greater White-fronted Goose, Bean Goose, and Swan Goose wintering there constituting 56.94%, 14.53%, and 49.93%, respectively, of their estimated populations along the migration flyway. This study provided a scientific foundation for the conservation of East Asian geese populations and offers critical support for the development of targeted conservation strategies in the future.