Activity Patterns of four Cranes in Poyang Lake, China: Indication of Habitat Naturalness

Abstract

Poyang Lake is one of the most important wintering habitats for cranes in China, and thousands of cranes including Siberian Crane (leucogeranus leucogeranus), White-naped Crane (Grus vipio), Hooded Crane (G. monacha) and Common Crane (G. grus) winter here annually. Despite their different conservation status, the four cranes have substantial ecological niche overlap and often form mixed flocks in their wintering grounds. To understand the persistence and coexistence of the species, we used time-budgeting to investigate how these sympatric cranes allocate time to their activities. Our results indicate that the cranes had more foraging time and less vigilance time at Poyang Lake than at other wintering sites. Also, the four cranes displayed significantly different activity patterns in the shared habitat. Compared with the smaller sized Common Cranes and Hooded Cranes, the larger sized Siberian Cranes and White-naped Cranes tended to be more relaxed, suggesting foraging ability decides the crane community structure as evidenced in many ecosystems. Our results suggested that Poyang Lake is crucial for the cranes conservation, which needs a transregional even global management strategy.