Authors: Clipp et al
Year: 2021
Publication: Ornithology
Publication Link: https://academic.oup.com/auk/article-abstract/138/4/ukab051/6363026?redirectedFrom=fulltext
Keywords: Atlantic Ocean, avian migration, Caribbean Sea, Gulf of Mexico, stopover, weather surveillance radar, wind
Abstract: Migrating birds contend with dynamic wind conditions that ultimately influence most aspects of their migration, from
broad-scale movements to individual decisions about where to rest and refuel. We used weather surveillance radar data
to measure spring stopover distributions of northward migrating birds along the northern Gulf of Mexico coast and
found a strong influence of winds over nonadjacent water bodies, the Caribbean Sea and Atlantic Ocean, along with the
contiguous Gulf of Mexico. Specifically, we quantified the relative influence of meridional (north–south) and zonal (west–
east) wind components over the 3 water bodies on weekly spring stopover densities along western, central, and eastern
regions of the northern Gulf of Mexico coast. Winds over the Caribbean Sea and Atlantic Ocean were just as, or more,
influential than winds over the Gulf of Mexico, with the highest stopover densities in the central and eastern regions
of the coast following the fastest winds from the east over the Caribbean Sea. In contrast, stopover density along the
western region of the coast was most influenced by winds over the Gulf of Mexico, with the highest densities following
winds from the south. Our results elucidate the important role of wind conditions over multiple water bodies on regionwide
stopover distributions and complement tracking data showing Nearctic–Neotropical birds flying nonstop from
South America to the northern Gulf of Mexico coast. Smaller-bodied birds may be particularly sensitive to prevailing
wind conditions during nonstop flights over water, with probable orientation and energetic consequences that shape
subsequent terrestrial stopover distributions. In the future, the changing climate is likely to alter wind conditions
associated with migration, so birds that employ nonstop over-water flight strategies may face growing challenges
Lay Abstract:
Winds encountered by migrating birds during over-water flights likely influence where they stop to rest and feed after
reaching land.
• We measured wind conditions over the Gulf of Mexico, Caribbean Sea, and Atlantic Ocean and used weather
surveillance radar data to quantify spring stopover distributions of migrating birds along the northern Gulf of
Mexico coast.
• We found winds over the Caribbean Sea and Atlantic Ocean were more influential on stopover distributions than
winds over the Gulf of Mexico.
• In the central and eastern regions of the coast, the highest stopover densities followed the fastest winds from the east
over the Caribbean Sea, while in the western region of the coast, the highest stopover densities followed winds from
the south over the Gulf of Mexico.
• This study clarifies relationships between wind conditions and stopover distributions through an important migration
corridor, finding support for the influence of winds over multiple water bodies.