Authors: Anderson et al.
Publication: Journal of Field Ornithology
Publication Link: https://onlinelibrary.wiley.com/doi/abs/10.1111/jofo.12374
Keywords: aeroecology, coastlines, ecological barrier, migration, ornithology, passerines
Abstract: Migrating birds often encounter ecological barriers to fueling and other costs that can
influence their flight directions. During spring migration, many migrants deviate westward along the southern
coast of Lake Erie’s western basin instead of continuing to fly the more northerly, broad-front direction and
crossing the lake. The goal of this study was to determine if migrants arriving at the same locations along the
southern coast of Lake Erie in autumn, after having now already flown over the lake, would similarly respond
to the coastal features despite the different decision making, adaptive profile. During the fall migrations of
2015–2017, flight directions of individual migrants, overwhelmingly passerines, were recorded by an infrared
camera from three coastal sites along the southern coast of Lake Erie’s western basin. The regional broad-front
direction of migration was taken from the WSR Doppler weather radar located near Cleveland, Ohio. Across
multiple analyses, no differences in flight directions were observed either across the three observation sites or
with respect to the broad-front direction. Generally, migrants flew in a south-southwesterly direction
irrespective of location. Further, we found no differences in the flight directions of migrants early in the night
compared to later in the night, suggesting that the energetic state did not substantially impact flight directions.
In contrast to spring migration, the ecological boundary on Lake Erie’s southern coast was not associated with
any change in the flight directions of songbirds during fall migration, suggesting that migratory context is a
critical factor determining how migrants may respond to environmental, topographic features.