有关棕头鸥和遗鸥两近似种的分类与分布问题研究

本文根据近几年的野外观察结果并分析有关文献资料，系统地比较研究了棕头鸥和遗鸥两近似种的分类和分布现状，直接依据野外活体形态并对照系列标本对两种鸥的成、幼鸟和雏鸟的形态及野外临别特征给出了较精确的描述，澄清了这两种鸥以往在分类上的混淆有分布认识上的错位，同时从生态－动物、地理和行为学的角度对两种鸥的现有分布和今后分布态势的演进做了分析论证。

ABOUT SOME UNCERTAINTY OF THE DISTRIBUTION AND TAXONOMY OF LARUS BRUNNICEPHALUS AND LARUS RELICTUS

This paper deals with comparative studies on the morphological characteristics and the range of the Brown headed Gull Larus brunnicephalus and the Relict Gull Larus relictus . It is indicated that in the past, the breeding ranges of the abovementioned two gull species had been separated from each other and later on in the beginning of 1990's became connected in Ordos of western Inner Mongolia due to the successful colonization of a flock of the Brown headed Gulls to the Ordos Highland. There is also some more evidence showing a tendency of the Brown headed Gulls in continuing their invading eastwards.