Bird migration research at tropical and south-temperate latitudes: A novel test of optimal migration theory

FONTANA, C.S.; RYDER, T.B.; CUETO, V.R.; LEVEY, D.J.; JAHN, A.E,; KETTERSON, E.D.; TUERO, D.T.

Renaissance Tuscany Il Ciocco in Lucca (Barga)

Conferencia; II Gordon Research Conference on Movement Ecology of Animals; 2019

Gordon Research Conferences

Any attempt to understand the ecological and evolutionary processesthat shape bird migration across the planet will be incomplete without moreinformation from tropical and south-temperate latitudes. We present aframework to conceptualize mechanisms underlying individual- and population-levelmigrations across latitudes. We focus on two types of migrants: intra-tropical migrantsthat breed and migrate entirely within the tropics, and austral migrants that breedat south-temperate latitudes of Africa, South America and Australia andoverwinter closer to the Equator. We hypothesize that because intra-tropical andaustral migrants have a ?slow life history,? they should employ a migration strategymore shaped by energetic needs (energy-selected) than migrants that breed north-temperatelatitudes, which should employ a migration strategy more shaped by time(time-selected). Our preliminary data on the migratory behavior of Turdus thrushes and Tyrannus flycatchers in North and South America show thatintra-tropical and austral migrants migrate more slowly, move across shorterdistances, and exhibit more variability in their migratory strategies thanconspecifics in North America. Research on these poorly understood systemspromises novel insights into variation in migratory strategies across taxa, andultimately on the mechanisms underpinning avian migratory strategies on arapidly changing planet.