Data from: Projected changes in prevailing winds for transatlantic migratory birds under global warming

A number of terrestrial bird species that breed in North America cross the
Atlantic Ocean during autumn migration when travelling to their
non-breeding grounds in the Caribbean or South America. When conducting
oceanic crossings, migratory birds tend to associate with mild or
supportive winds, whose speed and direction may change under global
warming. The implications of these changes for transoceanic migratory bird
populations have not been addressed. We used occurrence information from
eBird (1950–2015) to estimate the geographical location of population
centres at a daily temporal resolution across the annual cycle for 10
transatlantic migratory bird species. We used this information to estimate
the location and timing of autumn migration within the transatlantic
flyway. We estimated how prevailing winds are projected to change within
the transatlantic flyway during this time using daily wind speed anomalies
(1996–2005 and 2091–2100) from 29 Atmosphere-Ocean General Circulation
Models implemented under CMIP5. Autumn transatlantic migrants have the
potential to encounter strong westerly crosswinds early in their
transatlantic journey at intermediate and especially high migration
altitudes, strong headwinds at low and intermediate migration altitudes
within the Caribbean that increase in strength as the season progresses,
and weak tailwinds at intermediate and high migration altitudes east of
the Caribbean. The CMIP5 simulations suggest that, during this century,
the likelihood of autumn transatlantic migrants encountering strong
westerly crosswinds will diminish. As global warming progresses, the need
for species to compensate or drift under the influence of strong westerly
crosswinds during the initial phase of their autumn transatlantic journey
may be diminished. Existing strategies that promote headwind avoidance and
tailwind assistance will likely remain valid. Thus, climate change may
reduce time and energy requirements and the chance of mortality or
vagrancy during a specific but likely critical portion of these
species' autumn migration journey.