Ecological study reveals distinct upslope and downslope seasonal migrations governed by thermal regimes in montane birds, indicating divergent climate adaptation strategies.
Key Points
To examine the extent, patterns, and underlying thermal mechanisms of seasonal elevational range shifts among resident montane bird species.
Integrated citizen science observations from eBird with systematic field surveys across an elevational gradient in the Nilgiri Hills.
Assessed seasonal elevational shifts between the hottest and coldest quarters across 70 resident bird species present year-round.
Applied phylogenetic generalized least squares regressions to model relationships between species traits and elevational shifts.
A total of 77% (54/70) of analyzed species displayed seasonal shifts in elevational ranges, with 37% shifting downslope and 33% shifting upslope during winter.
Species with narrow thermal regimes predominantly shifted downslope in winter via niche tracking, whereas species with broad thermal regimes shifted upslope via niche switching.