Long-distance bird migration within South America revealed by light-level geolocators

JAHN, A.E,; LEVEY, D.J.; CUETO, V.R.; PINTO LEDEZMA, J.; TUERO, D.; FOX, J.W.; MASSON, D.

AUK

AMER ORNITHOLOGISTS UNION

Año: 2013 vol. 130 p. 223 - 229

0004-8038

Little is known about the timing of migration, migration routes, and migratory connectivity of most of the >230 species of birds that breed at south temperate latitudes of South America and then migrate towards the tropics to overwinter. We used light-level geolocators to track the migration of three male and three female Fork-tailed Flycatchers (Tyrannus savana) captured on their breeding territories in Argentina. All birds initiated fall migration between late January and late February, and migrated 45 to 66 km day-1 in a northwesterly direction through central South America to either one or two wintering areas. Five individuals first spent several weeks (in April and May) in western Amazonia (mainly Peru, northwestern Brazil and southern Colombia), before they movedeast to spend the rest of the nonbreeding season in central Venezuela and northern Brazil. One individual occupied primarily one wintering area in eastern Colombia, northwestern Brazil, and southwestern Venezuela. Fall migration took approximately 7–12 weeks to complete, and covered a distance of 2,888–4,105 km. We did not analyze spring migration data because of broad overlap with the austral spring equinox.These results represent the first data on the wintering locations, migration timing and routes of individual migrant passerine birds that breed in South America. Given the general lack of similar data for practically all migratory birds that breed in South America, geolocator technology has the potential to revolutionize our understanding of how birds migrate―and the threats they face―on South America’s rapidly changing landscape. Key words: Argentina, Fork-tailed Flycatcher, geolocator, Neotropical austral migrants, Tyrannus savana, Tyrannidae.