The influence of the abundance and availability of alternative food on the foraging behavior of wintering Siberian Cranes (Leucogeranus leucogeranus)

Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.