鄱阳湖越冬灰鹤和白枕鹤的数量与集群特征

Population Sizes and Flocking Features of Wintering Common Cranes and White-Naped Cranes in Poyang Lake

2012年10月至2013年4月,对鄱阳湖越冬灰鹤（Grus grus）和白枕鹤（Grus vipio）种群数量和分布、集群特征以及灰鹤的年龄组成进行调查.结果显示,灰鹤和白枕鹤数量单次记录到的最大值分别为599和600只.4个保护区34个湖泊（或农田）有18个湖泊（或农田）记录到灰鹤种群.灰鹤种群数量在1月初至3月初达到高峰,62.87％的灰鹤集中在鄱阳县白沙洲自然保护区.在12个湖泊（或农田）记录到白枕鹤分布,种群数量在2月底至3月初达到高峰,95.77％的白枕鹤集中在鄱阳湖国家级自然保护区.与以往鄱阳湖越冬鹤类种群分布相比,灰鹤主要集中的区域发生变化,而白枕鹤未发生变化.灰鹤和白枕鹤平均集群大小分别为（8.50±19.84）和（7.52±21.47）只,各时期差异均不显著（P＞0.05）.灰鹤集群以家庭群为主（占70.07％）,聚集群次之（占23.36％）;家庭群中2成1幼比例最大（占46.88％）,聚集群中以5～9只的集群比例最大（占71.88％）.灰鹤家庭群平均大小为（2.76±0.69）只,聚集群平均大小为（13.84±20.82）只,2种集群类型在各时期之间大小差异均不显著（P＞0.05）.灰鹤集群中幼体占20.21％.针对鄱阳湖2种鹤类分别提出了相应的保护措施.

Surveys were conducted from October 2012 to April 2013 of common cranes （Grus grus） and white-naped cranes （Grus vipio） wintering in the Poyang Lake for population size,distribution and flocking features,as well as age composition of the common cranes.The maximum number of common crane individuals in one entry of record was 599 and of white-naped crane individuals was 600.Common crane populations were observed and recorded in 18 of the 34 lakes （or farmland） surveyed in four nature reserves,and peaked in size during the period from early January to early March and 62.87％ of the population gathered in Baishazhou Nature Reserve in Poyang County.White-naped cranes were observed and recorded in 12 of the 34 lakes （or farmlands） surveyed in four nature reserves and peaked in population size from late February to early March and 95.77％ of the population were found in Poyanghu Nature Reserve.Comparison with the records of the past years reveals that changes happened in major gathering area of common cranes,but nothing did with white-naped cranes.The mean size of flocks of common cranes and of white-naped cranes was 8.50± 19.84 （n =148） and 7.52-±21.47 （n =63）,respectively,indicating no significant differences between the two species in any wintering periods （P＞0.05）.The flocks of common cranes were mostly family-based ones,which accounted for 70.07％,and flocks of individual gathering was the second,accounting for 23.36％.The flocks of families were mostly composed of families of two adults plus one offspring,each,which accounted for 46.88％.The flocks of individual gathering were often composed of 5-9 individuals each,which accounted for 71.88％.The mean flock size of the former was 2.76±0.69 （n=96） and of the latter 13.84±20.82 （n=32）.The two types of flocks did not change much in size with time period （P＞0.05）.In the flocks of common cranes,juveniles accounted for 20.21％.In light of the situation in the Poyang Lake,some corresponding measures have been proposed for protection of the two species of cranes therein.