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

ALEX E. JAHN, DOUGLAS J. LEVEY,1,3 VÍCTOR R. CUETO,2 JESÚS PINTO LEDEZMA,4 DIEGO T. TUERO,2 JAMES W. FOX,5,6 AND DIEGO MASSON2

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 southtemperate latitudes of South America and then migrate towards the tropics tooverwinter. We used light-level geolocators to track the migration of three male andthree female Fork-tailed Flycatchers (Tyrannus savana) captured on their breedingterritories in Argentina. All birds initiated fall migration between late January and lateFebruary, and migrated 45 to 66 km day-1 in a northwesterly direction through centralSouth America to either one or two wintering areas. Five individuals first spent severalweeks (in April and May) in western Amazonia (mainly Peru, northwestern Brazil andsouthern Colombia), before they moved east to spend the rest of the nonbreedingseason in central Venezuela and northern Brazil. One individual occupied primarilyone wintering area in eastern Colombia, northwestern Brazil, and southwesternVenezuela. Fall migration took approximately 7?12 weeks to complete, and covered adistance of 2,888?4,105 km. We did not analyze spring migration data because ofbroad overlap with the austral spring equinox. These results represent the first data onthe wintering locations, migration timing and routes of individual migrant passerinebirds that breed in South America. Given the general lack of similar data forpractically all migratory birds that breed in South America, geolocator technology hasthe potential to revolutionize our understanding of how birds migrate―and the threatsthey face―on South America?s rapidly changing landscape.