Inter- and intracontinental migration by the Eastern Kingbird (Tyrannus tyrannus)

Abstract

We recovered 12 archival geolocators deployed on Eastern Kingbirds (Tyrannus tyrannus) breeding in New York (NY; n = 3, 2 with 2 years of data), Nebraska (NE; n = 6, 1 with 2 years of data), and Oregon (OR; n = 3) to describe migratory routes, timing and rates of migration, nonbreeding season distributions, and migratory connectedness. NY fall migrants migrated along the Atlantic coast to Florida, flew either nonstop across the Gulf of Mexico (GoM; 2 of 3 birds) or stopped once along the way (Cuba and Cayman Islands in different years) to land in Yucatan/Central America. Fall birds from NE and OR arrived at the GoM in the region of the border between Texas and Louisiana, and most likely took a land route to Central America. In spring, all NY birds flew nonstop across the GoM, and once in North America, took a more inland route than in fall. Trans-GoM flights were more common among NE and OR birds in spring than fall. Birds migrated faster in spring than fall, and in both seasons, late departure was associated with more rapid migration. Migratory connectivity was low, and all birds from OR, and one bird from NE and NY each, occupied a single region in northwestern Amazonia (southern Colombia, northern Peru, and eastern Ecuador) while in South America. Most kingbirds from NE and NY were intratropical migrants, occupying 2 regions for periods of ≥30 d. The latter birds migrated farther south to western Brazil and northern Bolivia, but then moved north to later use the same area in northwestern Amazonia where other birds remained throughout the overwinter period. Northwestern Amazonia thus appears to be a critical area for all Eastern Kingbirds during the nonbreeding season, possibly because a prolonged wet season supports abundant fruit resources.