| Siberian Crane(Grus leucogeranus)is a bird of the family Gruidae.Siberian Crane were listed as Critically Endangered species by IUCN redlist.China Red Data Book of Endangered Animals also listed Siberian Crane as endangered species level and Siberian Crane were also listed as Class I on the China animal protection at the national level.Siberian Crane is mainly in the Asian continent.There are only about 3,500 remaining in the world.There are three populations of Siberian cranes.They all breed in northern Russia all migrating thousands of kilometres to wintering respectively in Iran,India and China.Central and western populations are of rare,the number of 99% are wintering in Poyang Lake,China.Currently the biggest threat of the eastern populations faced are habitat degradation of migrating stopover sites and wintering ground suitableility.Satellite location data are used to show migration routes and stopover sites through time.It is significance important to study Siberian crane migration by satellite tracking,to further understanding the crane migration,especially the crane spring migration routes and specific stopover sites in China.We installed seven satellite trackers at the back of cranes from Xianghai NNR,Momoge NNR,Nanji wetland NNR and Huanzidong national wetland park.The trackers data can be collected including site data(latitude,longitude and altitude),time,speed,location accuracy and so on.We sorted data and obtained migration routes in spring and fall.Besides,stopover sites were divided into five class,respectively,long-term stopover sites,short-term stopover sites,day and night stopover sites,night stopover sites and day stopover sites.The result are as follows:1.Migration Routes of the Tracked Siberian CranesThey were all breeding between lower Yana River and lower Indigirka River and they all migrating thousands of kilometres to spend the winter in Poyang Lake.And long-term stopover sites were in marsh in southwest Songnen Plain,northest China.Between wintering grounds and breeding grounds,the migration distance was 5594.83±371.70 km in spring 2015,and migration distance 5366.66±61.19 km in fall 2015.There is not significant difference on migratory distance between spring and fall migration,and not significant difference on fall migration distance between this study and Kanai's study,whether in breeding,wintering or important migration stopover sites.Qiqihar Wetland became less important as stopover sites for Siberian Crane in this study.There are many mountains in migration routes,Siberian Crane avoided Dabie Mountain only.According to the monitoring of the tracked cranes among the group,I think,it is feasible to release the rescued cranes into the wild in order that they return back to the wild population.2.Stopover sites of the tracked Siberian CranesLong-term stopover sites are located in Southwest Songnen Plain,northeast of China.six of eight Long-term stopover sites around the erlongtao river basin,including Momoge National Nature Reserve,Tumuji National Nature Reserve and between wetlands.The Siberian Cranes spring activity more dispersing than fall,but it is not significant between them.There six short-term stopover sites located around the Bohai,two of them located in Liaohe River delta,two in Shandong Yellow River Delta,the other two are located in Tangshan and chang island,respectively.From our findings,there are many resting stopover sites distributed in migration routes,mostly of them are night stopover sites.3.Migration Characteristics of the Tracker Siberian CranesWe can be seen from the tracking results,the tracked Siberian Cranes left the win tering grounds in the late March to the late April.And reach their breeding grounds fr om mid-late May to June in fall.Siberian Cranes' fall migration started in late mid-Sep tember,ended in early November.There is relationship between migration start time an d the local temperature,that is when the breeding average temperature below to 0? a nd the lowest temperature to-5~-10?,the cranes left breeding grounds.From the trac king results can be calculated,the migration time was about 60 d and rest time was 50 d in spring 2015,the migration time was about 50 d and rest time was 40 d fall 2015.We also found that more than 80% migration time was in stopover sites,60% of the time was in the long-term stopover sites.We believe that the crane spring migration distance between two successive migrat ory stopover in a short distance,stop long time,few stopover times;fall migration dist ance between two successive migratory stopover for a long distance,short time,more stopover times.instantaneous speed of Siberian Cranes is usually 50~60km/h.there are less 20% speed data higher than 70km/h.The highest velocity was 144.3km/h.In migration process,the flight altitude is usually 100~200m,the velocity above 1000 m were accounted less than 20%.Laizhou Bay and Caofeidian is the important stopover,which is mainly night stopover. |
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