基于卫星跟踪大天鹅春季迁徙时间及其影响因素

候鸟春季迁徙时间与其能否顺利完成迁徙过程，以及对繁殖地的成功选择和繁殖成效密切相关，通过对大天鹅越冬地和停歇地的春季迁徙时间选择原因及其影响因素进行分析，有助于深入理解候鸟春季迁徙时间策略和栖息地保护状况。2015年2月和12月，在河南三门峡湿地捕捉了60只越冬大天鹅并佩戴卫星跟踪器，获取了详细的大天鹅在越冬地和停歇地的春季迁徙时间等信息，并进一步分析了春季迁徙时间与气候因子的相关性。结果表明，大天鹅主要在夜间22：00-0：00和0：00-1：59迁离越冬地。大天鹅迁离越冬地的日期与温度呈显著性正相关，迁离时多选择顺风且风速较小的天气。大天鹅迁离越冬地后主要是在夜间飞行，而迁离停歇地后主要是在日间飞行。越冬地的温度越高，越有利于植物的生长，大天鹅可以快速地积累能量，提前开始春季迁徙。野外调查表明，内蒙古黄河中上游作为迁徙的重要停歇地，春季两岸捕鱼、农耕和放牧等为活动较多，因此大天鹅多选择在夜间觅食补充能量，在日间迁离。最后，针对黄河流域大天鹅栖息地的保护现状，提出了禁止经济开发项目、建立保护区和开展宣传教育等保护建议。

Using satellite tracking to identify the factors affecting the spring migration timing of whooper swans (Cygnus cygnus)

The success of the migration process, selection of breeding sites, and rearing of young for migratory birds is closely related to the timing of the spring migration. In our study, we used satellite tracking to analyze the factors affecting the timing of the spring migration of whooper swans (Cygnus cygnus) at wintering and stopover sites. The study aimed to understand the spring migration strategies of whooper swans and to identify important habitats for their conservation. In February and December 2015, sixty whooper swans wintering at the Sanmenxia wetland in Henan Province, China, were tagged with satellite transmitters. We determined the detailed timing of the spring migration at wintering and stopover sites and analyzed the correlation between the timing of the spring migration and climate factors. The results showed that the whooper swans wintering at the Sanmenxia wetland departed the wintering site from March 7 to March 8, and the departure date was significantly positively correlated with higher temperature and wind direction, but there was a significant negative correlation with wind speed. The whooper swans mainly migrated to the northwest from the wintering area, and the direction of migration had no significant correlation with wind direction and wind speed. The whooper swans generally departed the wintering site at night between 22:00 and 1:59, and they also started the spring migration downwind and during periods of low wind speed. The dates when the whooper swans were present in the stopover sites were mainly from late February to late March, and they tended to depart the stopover sites between 9:00 and 9:59. The proportion of whooper swans migrating in the day (52%) was slightly higher than at night (48%) during the spring migration, and the peak period of the whooper swan migration was from 6:00 to 12:59. The whooper swans mainly flew at night from the wintering to the first stopover sites, then during the day from the first stopover to the terminal sites. Higher temperatures at the wintering sites were beneficial for the growth of plants, which allowed the swans to rapidly accumulate energy reserves in advance of the migration. The field surveys indicated that human daytime activities such as fishing, farming, and grazing in the Yellow River valley, which contained important stopover sites for the spring migration, resulted in the swans foraging at night and flying during the day. To protect populations of whooper swans effectively, we suggest that existing threats to their stopover sites are addressed, including prohibiting development projects, building nature reserves, and improving public awareness.