Adaptive Habitat Selection Strategies of Human-Breeding Red-Crowned Cranes During the Early Stage of Rewilding

Wild-release is an important approach for the recovery of rare and endangered bird populations. However, individuals released into the wild often face challenges at the early stage, including limited wild experience, unstable resource availability, and a changed habitat preference. At present, systematic quantitative analyses of the spatiotemporal dynamics of ecological adaptation in wild-released rare and endangered birds are still limited. To fill this gap, this study focuses on six wild-released red-crowned cranes (Grus japonensis) in Jiangsu Yancheng National Nature Reserve for Rare Birds (YNNR). Based on 1 year of high-temporal-resolution GPS tracking data and the corresponding habitat information, we used spatiotemporal principal component analysis (stPCA) and Levins' niche breadth index to systematically reveal the patterns of habitat selection and habitat adaptation strategies of red-crowned cranes during the early stage after release. The results showed that the early adaptation of wild-released red-crowned cranes was a dynamic process of continuous exploration, repeated adjustment, and gradual stabilization. The stPCA identified two main adaptation gradients, reflecting the change between artificial and natural habitats, and the change from reliance on artificial feeding to a resource utilization strategy enhanced by independent foraging. Individuals at different age stages exhibited significant differences in their adaptation process: immature individuals tended to adapt their wild habitats through spatial exploration and habitat use structure adjustments, showing greater overall fluctuations and an expanding niche breadth. In contrast, adult individuals were more likely to adjust their resource acquisition mode; they adapted more quickly, showed a relatively stable habitat-use pattern, and had a smaller range of change in niche breadth. This study provides a systematic and quantitative view for evaluating the ecological adaptation process of wild-released birds, and offers a theoretical basis and practical reference for the protection of wild-released rare and endangered birds.