Stopover ecology of Red-flanked Bush Robin ( Tarsiger cyanurus) at Maoershan, Northeast China

Abstract

The conservation of migratory songbirds in China faces challenges similar to those in other parts of the world such as Europe and North America. Migratory songbirds have a complex life history and are associated with large spatial scale. Events that occur during migration play a vital role in determining population status. Little is known about the stopover behavior of migratory songbirds in China during their passage, including stopover duration, energetic condition (e.g., the amount of fat stores), and the habitat of these birds. We investigated migration timing, stopover duration, change of energetic condition and sex-related variations among Red-flanked Bush Robins ( Tarsiger cyanurus) at a stopover site in Northeast China. A total of 1 751 Red-flanked Bush Robins were captured in the fall of 2002, with further 684 captured in the spring of 2003. The body mass of the fall birds was higher than that of the spring ones. The condition index (i.e., body mass adjusted for body size) was lowest among spring females. Birds were more likely to stay longer in fall than in spring. We detected a positive relationship between the time of initial capture and condition index regardless of season or sex, suggesting that the birds were able to replenish energy stores. The net daily mass gain was the highest among males in the fall (3% of body mass). The net daily mass gain would sustain a flight of 0.6 hours for females and 3.1 hours for males in the fall. The stopover biology of Red-flanked Bush Robins is similar to that of some migratory songbirds in Europe and North America. For example, the spring passage time and fat store variation between the sexes concurs with the hypothesis that males are selected to arrive at their breeding grounds as early as food resources or climatic conditions are adequate in the spring. Further research on stopover ecology is urgently required in China to achieve a better understanding of migratory behavior and ensure the conservation of these migratory songbirds.