Individual consistency in spatiotemporal characteristics of migratory Whimbrels in the East Asian-Australasian Flyway

Many migratory birds exhibit interannual consistency in migration schedules,routes and stopover sites.Detecting the interannual consistency in spatiotemporal characteristics helps understand the maintenance of migration and enables the implementation of targeted conservation measures.We tracked the migration of Whimbrel(Numenius phaeopus)in the East Asian-Australasian Flyway and collected spatiotemporal data from individuals that were tracked for at least two years.Wilcoxon non-parametric tests were used to compare the interannual variations in the dates of departure from and arrival at breeding/nonbreeding sites,and the inter-annual variation in the longitudes when the same individual across the same latitudes.Whimbrels exhibited a high degree of consistency in the use of breeding,nonbreeding,and stopover sites between years.The variation of arrival dates at nonbreeding sites was significantly larger than that of the departure dates from nonbreeding and breeding sites.Repeatedly used stopover sites by the same individuals in multiple years were concentrated in the Yellow Sea coast during northward migration,but were more widespread during southward migration.The stopover duration at repeatedly used sites was significantly longer than that at sites used only once.When flying across the Yellow Sea,Whimbrels breeding in Sakha(Yakutia)exhibited the highest consistency in migration routes in both autumn and spring.Moreover,the consistency in migration routes of Yakutia breeding birds was generally higher than that of birds breeding in Chukotka.Our results suggest that the northward migration schedule of the Whimbrels is mainly controlled by endogenous factors,while the southward migration schedule is less affected by endogenous factors.The repeated use of stopover sites in the Yellow Sea coast suggests this region is important for the migration of Whimbrel,and thus has high conservation value.

Predicting the non-breeding distributions of the two Asian subspecies of Black-tailed Godwit using morphological information

Until recently,Limosa limosa melanuroides was thought to be the only subspecies of Black-tailed Godwit in the East Asian-Australasian Flyway.For this reason,all previous occurrences and counts of Black-tailed Godwits in the flyway have been assigned to melanuroides.However,a larger-bodied subspecies,bohaii,has recently been discovered in the flyway.As a result,the occurrence of Black-tailed Godwits in the flyway needs to be reconsidered such that the specific distribution of each subspecies becomes known.To this end,we developed a simple discriminant function to assign individuals to subspecies based on their bill and wing length.Cross-validation with individuals known to be bohaii or melanuroides,based on molecular analysis,showed the developed function to be 97.7%accurate.When applied to measurements of godwits captured at 22 sites across 9 countries in East-Southeast Asia and Australia,we found that bohaii and melanuroides occurred at most sites and overlapped in their distribution from Kamchatka to Australia.We examined photos from all along the flyway to verify this surprising result,confirming that both subspecies co-occur in most locations.Based on these results,we hypothesise that bohaii and melanuroides from the west of their breeding ranges mostly migrate over Chinese mainland.Birds of both subspecies from the east of their ranges are expected to migrate along the Pacific Ocean.We encourage ringing groups in East-Southeast Asia and Australia to use this simple method to keep adding knowledge about Black-tailed Godwits in the East Asian-Australasian Flyway.

Detecting the non-breeding region and migration route of Whimbrels(Numenius phaeopus rogachevae)in the East Asian–Australasian Flyway

Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration.Five subspecies have been recognized in the Whimbrel(Numenius phaeopus)in Eurasia.Ssp.rogachevae is the most recently described subspecies.It breeds in Central Siberia,while its non-breeding region and migration routes are still unclear.We tracked the migration of Eurasian Whimbrels captured at three non-breeding sites(Moreton Bay in east coast of Australia,Roebuck Bay in Northwest Australia and Sungei Buloh Wetland in Singapore)and two migration stopover sites(Chongming Dongtan and Mai Po Wetland in China).We determined the breeding sites and inferred the subspecies of the tagged birds in the East Asian–Australasian Flyway(EAAF)based on the known breeding distribution of each subspecies.Of the 30 tagged birds,6 and 21 birds bred in the breeding range of ssp.rogachevae and variegatus,respectively;one bred in the presumed transition area between the breeding range of ssp.phaeopus and rogachevae,and two bred in the region between the breeding range of ssp.rogachevae and variegatus.The birds that bred in the ssp.rogachevae breeding range spent their non-breeding season in the northern Sumatra,Singapore,East Java and Northwest Australia and mainly stopped over along China's coasts during migration.None of our birds bred in the exclusive breeding range of the phaeopus subspecies.Previous studies have predicted that rogachevae whimbrels migrate along the Central Asian Flyway and spend the non-breeding season in West India and East Africa.We found that at least some rogachevae whimbrels migrate along the EAAF and spend the non-breeding season in Southeast Asia and Australia.The ssp.phaeopus is at best sparsely distributed in the EAAF in the west region,or possibly does not occur at all.