Home Range And Migration Of Wintering Whooper Swan (Cygnus Cygnus) At Sanmenxia Reservoir Area And Spread Of HPAI H5N1

Whooper Swan(Cygnus cygnus),waterfowl of the family Anatidae and order Anseriformes,listed as the second national key protected birds in China.The breeding sites of Whooper Swans in China are located at Zhalong,Xingkai Lake,Sanjiang plain of Heilongjiang,and Ordos plateau,Hulun Buir League,Dalai Lake of Inner Mongolia,and Chaidamu basin and Qinghai Lake of Qinghai,and Sailimu Lake,Aibi Lake,Yili River of Xinjiang etc.The major wintering areas are located at the eastern coast of Rongcheng and Dengkou,Yellow River Delta,Sanmenxia Reservoir Area of Henan,Gahai of Gansu,Qinghai Lake and Southern Xinjiang,occasionally found in napahai Lake,Yunnan,Fujian and Taiwan etc.Since the 21 st century,previous studies on Whooper Swan mainly include the number and distribution,behavioral ecology,habitat selection,diet analysis and avian influenza epidemic at home and abroad.In early 2015,a highly pathogenic avian influenza(HPAI)H5N1 that infected whooper swans and other wild ducks outbroke at Sanmenxia Reservoir Area,China,arousing serious concerns about the migratory linkages between wintering and breeding grounds of whooper swans,as well as the geographic transmission of H5N1.Therefore,whooper swans in east Asia have been considered sentinel species in the long-distance spread of HPAI H5N1 virus.In this study,67 whooper swans were tracked with GPS transmitters from 2014 to 2016,and the tracking data were combined with historical banding recovery locations to delineate migration routes,key stopover sites,and terminal grounds in relation to H5N1 outbreak sites.In addition,investigations on population dynamic,habitat selection and home range of the wintering whooper swans at Sanmenxia Reservoir Area of Henan were performed.The main conclusions are as follows:1.Home range and population ecology of wintering whooper swan at Sanmenxia Reservoir Area.In recent years,the population of species at Sanmenxia Reservoir Area increased rapidly,however,it decreased after the epidemic event in 2016.Based on the satellite tracking data and field investigation,wintering grounds of whooper swan include Sanmenxia swan Lake of National Urban Wetland Park,Sanwan of Pinglu County(Shanxi),Wangguan of Sanmenxia City and Shengtian Lake of Ruicheng County(Shanxi).Kernel density estimation(KDE)was used for home range analysis at levels of 90% and 50%.Movement zone of swans tend to shift from Swan lake of Sanmenxia to Sanwan lake of Pinglu.Home range of Sanmenxia swan Lake was significantly different from December to March(F=31.4,P=0.000).Movement zone area at 90% level is significantly negative correlated with monthly average temperature,but not significantly correlated at 50% level.Concealment level of roost sites were changed by ‘high-low-high'.24 hours home range at three stages varied strongly,but daily area at the same stage is similar.Daily area of the 24 hours is significantly positive correlated with temperature at stage ? and no correlation at stage ?,and negative correlation at stage ?,indicating that home range of wintering swans is effected by temperature.The habitat vegetation utilization is highest at stage ? with foraging Sedge(Cyperus glomeratus Linn),Barnyard grass(Echinochloa crusgalli Beauv),leaves of Reed(Phragmites australis),Cattail roots(Typha angustifolia)and the stems and leaves of the Lotus(Nelumbo nucifera).The forage habits at stage ? and ? depend on artificial feeding.Behaviors of alarming,foraging and locomotion at three stages are more common than other behaviors,which is correlated with temperature.The alarming,fighting and calling behaviors for adult whooper swans were higher than these of juvenile ones.The foraging,maintencace and resting behavior for adult swans were higher than these of juvenile ones.Alarming,fighting,foraging,maintencace and locomotion behaviors between adult and juvenile whooper swans are significantly different.2.Migration routes and key stopover sites.All tracked swans successfully departed from their wintering grounds during spring in 2014 to 2016.Whooper swans departed the wintering grounds between 17 February and 27 March(average 6 March).According to GPS-tracking data,whooper swans appeared nocturnal migration(night:day=3.2:1)from wintering grounds and diurnal migration from stopover sites(night:day=1:3.0),which might be related to human disterbance,food and photoperiod.The heading course of whooper swan departed from Sanmenxia Reservoir Area was northwest(303.68±63.39°),and there was no significant correlation with wind speed.The average distance between wintering and breeding sites was 2081±372 km with a maximum of 2646 km.Migration speed was 51.6±8 km/h(n=44),with a maximum of 104.4 km/h.There was no significant variance between nocturnal and diurnal speed,and no correlation with body structure.It suggests that the cluster patterns is dominant during the migration.The adult whooper swans arrived breeding grounds more earlier than the juvenile ones.Whooper swans migrated along the Jin-yu,Shan-jin,and Inner Mongolia reaches of the Yellow River and its tributaries(including Yan River,Wuding River,Tuwei River and Fen River etc.),and flew over the Yin Mountains in China.Of the 67 tracked swans,34 ones reached the terminal sites in central-northern and western Mongolia ranging from the westernmost Lakes to central Gobi wetlands of Ongiyn Gol,Baydrag Gol and Tuin River,as well as northern-central basins of the Orkhon River,Tuul River and Selenga River,and northernmost Shinshkhed River and Khovsgol Lake during 27 February to 23 May.The Yumenkou wetlands,Wuding Riverine wetlands,Hongjian Nuur,Ordos Lakes and the reaches of the Yellow River in Inner Mongolia were all identified as key stopover sites in China.Ten whooper swans spent the summer in China and three were confirmed dead for unknown reasons,with their transmitters found in the Yellow River,Wuding River and Hongjian Nuur.3.Relationship between the migration of whooper swans and HPAI H5N1 events.Virology results revealed that the H5N1 clade 2.3.2.1.c collected from Bayannur,Baotou,Ordos and Yulin along the Yellow River showed a high degree homology(99.7%)with the epidemic strain from the Sanmenxia Reservoir Area.Brown bridge model indicates that AI(avian influenza)events outbroke in China and Mongolia overlapped with the spring migration pathway of whooper swans at 95% level.Buffer area of 10 km and 50 km around AIV events in China and Mongolia showed that movements of whooper swans were intensive.Our results identify a previously unknown migratory link of whooper swans in central China and confirm that whooper swans could carry HPAI virus during migration,resulting in long-distance transmission.To establish baseline information about the spring migration of water birds,in March 2015 and April 2016 we conducted surveys on the current status and habitats of Whooper swans along the upper and middle reaches of the Yellow River in Inner Mongolia.According to GPS-tracking data,the upper and middle reaches of Yellow River are important stopover sites for spring migratory Whooper swans,where the most swans stayed for the longest period.Their diurnal and night movements were roughly similar.The EVI(Enhanced Vegetation Index)at the upper and middle reaches of Yellow River shows very low.Compared with that of the 90% level,the home range size of the 50% level and corresponding EVI was much lower from Dengkou County to Tumed Right Banner,a location that should be considered an important area for avian influenza surveillance.During our field surveys,we discovered that these stopover sites were located on farmland around the Yellow River,and provided abundant food and better shelter habitats for Whooper swans and other water birds.Thus,key stopover sites should be as important Avian Influenza surveillance zone.