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Aim This paper examines the migration of the tropical nectarivorous Lat Leptonycteris curasoae considered as a latitudinal migrant th,lr breeds in south-west United States and northern Mexico in spring and migrates southward during fall. We tested the hypothesis that the latitudinal migration occurs only locally given by the local availability of bat resources, leading to migratory movements in zones with seasonal scarcity of resources and to resident bat populations where resources are available throughout the year.

Localization We analysed the presence of L. curasoae along its distribution range in North America (between 14 degrees N and 33 degrees N). Study cases were also conducted in three Mexican localities: the Tehuacan Valley (17 degrees 48’-18 degrees 58’N and 96 degrees 48’-97 degrees 43’W), Sonoran Desert (28 degrees 41’N and 110 degrees 15’W), and the coast of Jalisco (19 degrees 32’N and 105 degrees 07’W).

Methods Geographic evidence for latitudinal migration of L. curasoae was analysed using 94-year capture records housed in twenty-two collections of North America. Records were analysed using a Geographical Information System (GIS), in which floral resources and capture records were integrated. Monthly captures in the Tehuacan Valley were conducted during three years and bats abundance and reproductive status were correlated with the phenology of brit resources. Bat captures were also conducted during two consecutive years in an extratropical desert during winter and spring, and during one spring in the coast of Jalisco.

Results The latitudinal migration of L, curasoae in North America only occurs at latitudes near 30 degrees N, whereas bats may be residents at latitudes lower than 21 degrees N. Captures were associated always to the availability. Of floral resources in both geographical and local scales.

Main conclusions The existence of resident populations in the tropics with two reproductive events support the hypothesis that migration only occurs in the northern distribution limit of this nectar-feeding bat.