eLife Assessment
This important and creative study finds that the uplift of the Qinghai-Tibet Plateau - via its resultant monsoon system rather than solely its high elevation - has shifted avian migratory directions from a latitudinal to a longitudinal orientation. The authors have expanded and clarified their lines of evidence (including an enlarged tracking set and explicit caveats on species-level eBird inference), such that the central claims are now solid. The conclusions - that monsoon dynamics, rather than elevation per se, are most consistent with observed longitudinal reorientation - illustrates how large, community-sourced and climate-model datasets can inform continent-scale shifts in migratory behavior over time that complement traditional approaches.