西藏阿里班公错斑头雁的种间巢寄生行为

Interspecific Nest Parasitism in Bar-headed Geese at Pangong Lake in Ngari Prefecture, Tibet

2016年6月2日,我们在对西藏阿里地区班公错鸟岛进行鸟类调查时,发现了斑头雁(Anser indicus)将卵产于棕头鸥(Larus brunnicephalus)的巢中,是一种间巢寄生行为。对于发生这种现象的原因,我们初步推测,一种原因可能是繁殖地的巢址和巢材资源短缺,鸟岛上巢材可能无法满足两个鸟种筑巢的需要,个别斑头雁由于巢材短缺,无法顺利筑巢,因此将卵产于棕头鸥的巢中。另一种可能原因是,某些斑头雁由于巢被破坏或卵被捕食,在迁徙之前已没有时间再完成下一轮的繁殖活动,由于斑头雁与棕头鸥食性差异较大,但由于斑头雁为早成鸟,孵出的雏雁不必接受棕头鸥纯肉食的饲喂,也使得这种巢寄生成为可能。

On June 2, 2016, during our survey on the breeding waterbirds colony at Pangong Lake in Ngari Prefecture, Tibet, we found two eggs of Bar-headed Geese （Anser indicus） were laid in an incubating nest of the Brown-headed Gulls （Larus brunnicephalus）. It was speculated preliminarily of two reasons for this interspecific nest parasitism behavior. One might be the shortage of breeding nest sites and nest material resources for the geese and gulls in the smaller breeding island. The other might be that some nests and eggs of geese being predated, and the birds had no time to complete the next reproduction before the fall migration. We did not follow the fate of this nest. The diets of these two bird species were different, however, the precocial geese fledglings might not needed to be fed by Brown-headed Gulls, making it possible for this interspecific nest parasitism.