Abstract:Breeding represents a crucial phase in avian life cycles, and understanding their breeding status and nest site locations is essential for conserving endangered species. However, for those large waterbirds, their breeding sites are often hidden and located in remote areas, making them difficult to identify through field observations. Recent advancements in satellite tracking systems and data analysis have significantly improved methods for identifying bird movement patterns and breeding status, which classify movement patterns by fitting movement models to trajectory data, enabling the identification of bird movement states. In this study, we compared the accuracy in determining breeding status and identify nesting sites of three safe and convenient satellite tracking-based methods (displacement-time curve method, nestR package and recurse package in R program) using Hooded Crane (Grus monacha) as a case study. Our aim is to provide an efficient and accurate method for identifying bird nesting sites. The results showed that Hooded Cranes utilized nest sites for breeding from early May to early June, with a duration of approximately 31 days. They exhibited site fidelity to their breeding nest locations. Each method exhibited unique advantages and limitations. The three satellite tracking-based methods produced consistent results (Kappa = 0.685), while field observations yielded significantly different outcomes. Regarding Hooded Crane breeding data, 10 cases classified as non-breeding through field observations were identified as breeding by all three satellite tracking-based methods. No significant differences were found in nesting start date, hatching end date, breeding duration, or nest site locations across methods. The consistency of nest site usage days was moderate, while the consistency of nesting start and end dates was high. The locations of White-naped Crane nest sites identified by the three methods were largely consistent, mainly distributed in Heilongjiang Province, Russia's Khabarovsk Krai, Amur Oblast, and the Jewish Autonomous Oblast. The summer breeding locations of individual White-naped Cranes were relatively fixed. The nestR package emerged as the most user-friendly tool among tested methods, providing intuitive results despite requiring accuracy enhancements. Among the methods tested, the nestR package proved to be the most convenient, with intuitive results, though its accuracy requires further improvement. We recommend primarily employing the nestR package for assessing waterbird breeding sites and timing, supplemented by the recurse package and displacement-time curve method. Parameter adjustments should be implemented to enhance accuracy, with results validated through integration with field survey methods. This study provides methodological support for determining the reproductive status of rare and endangered species and further providing conservation strategies.