Time Budgets of Wintering Red-Crowned Cranes: Effects of Habitat, Age and Family Size

The red-crowned crane (Grus japonensis) is an endangered species only found in East Asia. Due to wetland loss and degradation, many cranes have changed their wintering feeding habitats from natural grasslands to artificial wetlands, such as rice fields. Thus we want to know whether cranes relocate the time budgets with respect to habitat, and also with the age and family size. This study was conducted in Yancheng Nature Reserve during winters 2009 and 2011. We found cranes devoted more time to feeding but less to vigilance in grasslands, whereas the pattern was opposite in farmlands. Compared to juveniles, adults spent less time feeding but more time being vigilant. Cranes showed a similar time budget between different family sizes. These results indicate cranes relocate their behavioral time budgets according to their feeding habitats, which are closely related to human disturbance. We suggest reducing human activities in farmlands during the wintering period, as well as conserving natural wetlands in the wintering areas, to safeguard and ensure the wild population of red-crowned cranes.