The State of Migratory Landbirds in the East Asian Flyway: Distributions, Threats, and Conservation Needs

Pavel Ktitorov,Colin R Trainor,Desmond Allen,Luke Gibson,Ding Li Yong,Alexander Kondratyev,Philip D Round,Sayam U Chowdhury,Wieland Heim,Olga Kulikova,Chang-Yong Choi,Judit K Szabo

doi:10.3389/fevo.2021.613172

Abstract

With nearly 400 migratory landbird species, the East Asian Flyway is the most diverse of the world’s flyways. This diversity is a consequence of the varied ecological niches provided by biomes ranging from broadleaf forests to arctic tundra and accentuated by complex biogeographic processes. The distribution and migration ecology of East Asian landbirds is still inadequately known, but a recent explosion in the number of studies tracking the migration of raptors, cuckoos, kingfishers and passerines has greatly increased our knowledge about the stopover and wintering ecology of many species, and the migratory routes that link northeast Eurasia and the Asian tropics. Yet the East Asian Flyway also supports the highest number of threatened species among flyways. Strong declines have been detected in buntings (Emberizidae) and other long-distance migrants. While the conservation of migratory landbirds in this region has largely focused on unsustainable hunting, there are other threats, such as habitat loss and increased agro-chemical use driven directly by land cover change and climate-related processes. Important knowledge gaps to be addressed include (1) threats affecting species in different parts of their annual cycle, (2) range-wide population trends, (3) ecological requirements and habitat use during the non-breeding season, and (4) the conservation status of critical wintering sites (including understudied farming landscapes, such as rice fields) and migration bottlenecks along the flyway.

Highlights

The decline of migratory species is a global conservation concern (Wilcove and Wikelski, 2008) across the world’s major flyways (Lloyd-Evans and Atwood, 2004; Galbraith et al, 2014; Beresford et al, 2019)
No significant differences between spring and autumn migration speed/duration are evident in non-passerines, e.g., in satellitetracked Oriental honey buzzard Pernis ptilorhynchus (Yamaguchi et al, 2008) and great bustard Otis tarda (Kessler et al, 2013)
Drawing from diverse sources, we found evidence of trapping or trade for at least 180 of the over 380 migratory landbird species, representing nearly half (47%) of all species in the East Asian Flyway (EAF)

Summary

Introduction

The decline of migratory species is a global conservation concern (Wilcove and Wikelski, 2008) across the world’s major flyways (Lloyd-Evans and Atwood, 2004; Galbraith et al, 2014; Beresford et al, 2019). While there are few ecological barriers in the west in the form of mountain ranges, the EAF contains extensive island chains at its eastern fringe and the vast Indo-Australian archipelago spanning the tropical belt. These island chains collectively pose complex barriers in the form of sea-crossings for migrating landbirds (Kuroda, 1961; Ellis et al, 1990; Yamazaki et al, 2012; Nourani et al, 2018) unmatched in other flyways

Objectives

Findings

Conclusion