Convergence of broad-scale migration strategies in terrestrial birds

Migration is a common strategy used by birds that breed in seasonal environments. Selection for greater migration efficiency is likely to be stronger for terrestrial species whose migration strategies require non-stop transoceanic crossings. If multiple species use the same transoceanic flyway, then we expect the migration strategies of these species to converge geographically towards the most optimal solution. We test this by examining population-level migration trajectories within the Western Hemisphere for 118 migratory species using occurrence information from eBird. Geographical convergence of migration strategies was evident within specific terrestrial regions where geomorphological features such as mountains or isthmuses constrained overland migration. Convergence was also evident for transoceanic migrants that crossed the Gulf of Mexico or Atlantic Ocean. Here, annual population-level movements were characterized by clockwise looped trajectories, which resulted in faster but more circuitous journeys in the spring and more direct journeys in the autumn. These findings suggest that the unique constraints and requirements associated with transoceanic migration have promoted the spatial convergence of migration strategies. The combination of seasonal atmospheric and environmental conditions that has facilitated the use of similar broad-scale migration strategies may be especially prone to disruption under climate and land-use change.

[1]  R. Rigby,et al.  Generalized Additive Models for Location Scale and Shape (GAMLSS) in R , 2007 .

[2]  Nils Warnock,et al.  Conserving migratory land birds in the new world: do we know enough? , 2010, Ecological applications : a publication of the Ecological Society of America.

[3]  R. Rigby,et al.  Generalized additive models for location, scale and shape , 2005 .

[4]  Richard T. Holmes,et al.  Variation in survivorship of a migratory songbird throughout its annual cycle , 2002 .

[5]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[6]  W. Richardson.  Timing of Bird Migration in Relation to Weather: Updated Review , 1990 .

[7]  Julia Delingat,et al.  Stopover behaviour and departure decision of northern wheatears, Oenanthe oenanthe, facing different onward non-stop flight distances , 2001, Behavioral Ecology and Sociobiology.

[8]  T. Alerstam,et al.  When and where does mortality occur in migratory birds? Direct evidence from long-term satellite tracking of raptors. , 2014, The Journal of animal ecology.

[9]  R. Zink.  The evolution of avian migration , 2011 .

[10]  Thomas G. Dietterich,et al.  The eBird enterprise: An integrated approach to development and application of citizen science , 2014 .

[11]  P. López‐López,et al.  Weather conditions promote route flexibility during open ocean crossing in a long-distance migratory raptor , 2011, International journal of biometeorology.

[12]  Steve Kelling,et al.  Documenting stewardship responsibilities across the annual cycle for birds on U.S. public lands. , 2015, Ecological applications : a publication of the Ecological Society of America.

[13]  G. Vallis,et al.  Response of the large‐scale structure of the atmosphere to global warming , 2015 .

[14]  W. Hochachka,et al.  The implications of mid-latitude climate extremes for North American migratory bird populations , 2016 .

[15]  H. Winkler,et al.  On the ecomorphology of migrants , 2008 .

[16]  H. Schmaljohann,et al.  The nature of the migration route shapes physiological traits and aerodynamic properties in a migratory songbird , 2014, Behavioral Ecology and Sociobiology.

[17]  J. Blas,et al.  Individual improvements and selective mortality shape lifelong migratory performance , 2014, Nature.

[18]  T. Vincenty.  DIRECT AND INVERSE SOLUTIONS OF GEODESICS ON THE ELLIPSOID WITH APPLICATION OF NESTED EQUATIONS , 1975 .

[19]  Kenneth P. Able,et al.  The Role of Weather Variables and Flight Direction in Determining the Magnitude of Nocturnal Bird Migration , 1973 .

[20]  B Kranstauber,et al.  Global aerial flyways allow efficient travelling. , 2015, Ecology letters.

[21]  D. Lack.  Bird migration and natural selection , 1968 .

[22]  S. Åkesson,et al.  Long-distance migration: evolution and determinants , 2003 .

[23]  Steve Kelling,et al.  Population-level scaling of avian migration speed with body size and migration distance for powered fliers. , 2013, Ecology.

[24]  C. L. Archer,et al.  Historical trends in the jet streams , 2008 .

[25]  Steven C. Latta,et al.  Recent advances in understanding migration systems of New World land birds , 2010 .

[26]  K. Thorup,et al.  Orientation of vagrant birds on the Faroe Islands in the Atlantic Ocean , 2012, Journal of Ornithology.

[27]  Steven W. Running,et al.  Suitable Days for Plant Growth Disappear under Projected Climate Change: Potential Human and Biotic Vulnerability , 2015, PLoS biology.

[28]  T. Price,et al.  Correlates of wing morphology with foraging behaviour and migration distance in the genus Phylloscopus , 1995 .

[29]  K. Able.  Fall Migration in Coastal Louisiana and the Evolution of Migration Patterns in the Gulf Region , 1972 .

[30]  Felix Liechti,et al.  Birds: blowin’ by the wind? , 2006, Journal of Ornithology.

[31]  H. Kokko.  Competition for early arrival in migratory birds , 1999 .

[32]  Alison J. Stattersfield,et al.  Key conservation issues for migratory land- and waterbird species on the world's major flyways , 2008, Bird Conservation International.

[33]  D. Fink,et al.  Spring phenology of ecological productivity contributes to the use of looped migration strategies by birds , 2014, Proceedings of the Royal Society B: Biological Sciences.

[34]  D. Griffin,et al.  Radar observations of bird migration over the Western North Atlantic Ocean , 1979, Behavioral Ecology and Sociobiology.

[35]  B. R. Bowring,et al.  THE ACCURACY OF GEODETIC LATITUDE AND HEIGHT EQUATIONS , 1985 .

[36]  Kevin Sahr,et al.  HEXAGONAL DISCRETE GLOBAL GRID SYSTEMS FOR GEOSPATIAL COMPUTING , 2011 .

[37]  G. Mitchell,et al.  Automated telemetry reveals age specific differences in flight duration and speed are driven by wind conditions in a migratory songbird , 2015, Movement ecology.

[38]  P. Marra,et al.  Transoceanic migration by a 12 g songbird , 2015, Biology Letters.

[39]  Marisa C. W. Lim,et al.  Citizen-science data provides new insight into annual and seasonal variation in migration patterns , 2015 .

[40]  J. Rappole,et al.  Factors affecting migratory bird routes over the Gulf of Mexico , 1994, Bird Conservation International.

[41]  D. Douglas,et al.  Hemispheric-scale wind selection facilitates bar-tailed godwit circum-migration of the Pacific , 2014, Animal Behaviour.

[42]  K. Sahr,et al.  Geodesic Discrete Global Grid Systems , 2003 .

[43]  J. Wingfield,et al.  Regulation of Migration , 2007 .

[44]  T. Williams,et al.  An Oceanic Mass Migration of Land Birds , 1978 .

[45]  Philip K. Stoddard,et al.  Computer simulation of autumnal bird migration over the western North Atlantic , 1983, Animal Behaviour.

[46]  C. Peña-Ortiz,et al.  Observed trends in the global jet stream characteristics during the second half of the 20th century , 2013 .

[47]  J. Houghton,et al.  Climate Change 2013 - The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change , 2014 .

[48]  Steve Kelling,et al.  The role of atmospheric conditions in the seasonal dynamics of North American migration flyways , 2014 .

[49]  David C. Douglas,et al.  Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier? , 2008, Proceedings of the Royal Society B: Biological Sciences.

[50]  Bruno Bruderer,et al.  Flight behaviour of nocturnally migrating birds in coastal areas - crossing or coasting , 1998 .

[51]  B. Bruderer,et al.  The relevance of wind for optimal migration theory , 1998 .

[52]  W. Fiedler.  Ecomorphology of the External Flight Apparatus of Blackcaps (Sylvia atricapilla) with Different Migration Behavior , 2005, Annals of the New York Academy of Sciences.

[53]  T. Piersma.  Phenotypic flexibility during migration: optimization of organ size contingent on the risks and rewards of fueling and flight? , 1998 .

[54]  Steve Kelling,et al.  Migration timing and its determinants for nocturnal migratory birds during autumn migration. , 2015, The Journal of animal ecology.

[55]  K. Cook,et al.  Springtime Intensification of the Great Plains Low-Level Jet and Midwest Precipitation in GCM Simulations of the Twenty-First Century , 2008 .

[56]  Thomas Alerstam,et al.  Optimal bird migration revisited , 2011, Journal of Ornithology.