Connectivity patterns and key non-breeding areas of white-throated bluethroat (Luscinia svecica) European populations

摘要

Using ring recovery data from the EURING databank, the aims of this study were: (1) to identify the chief migration and wintering areas of white-throated bluethroat European subspecies, L. s. namnetum, L. s. cyanecula and L. s. azuricollis, (2) to evaluate the degree of connectivity between breeding and non-breeding regions and determine the migration patterns of each subspecies, and (3) to evaluate whether recovery data are sufficient to answer the previous questions adequately. Most of the recoveries were obtained during the autumn migration period (n = 155, 68.9%), followed by winter (n = 49, 21.8%) and spring (n = 21, 9.3%). For L. s. azuricollis, we did not find any ring recoveries at more than 100 km in autumn or spring, and there were none at all in winter. All analyses thus relate to L. s. cyanecula and L. s. namnetum. Both subspecies move across a NE SW axis from their breeding to their wintering areas within the circum-Mediterranean region, mainly in Iberia, following population-specific parallel migration routes. L. s. namnetum mainly uses the Atlantic coastal marshes from France to south-western Iberia, where the chief wintering areas are found. L. s. cyanecula, however, uses both Atlantic and Mediterranean wetlands in autumn, but only those in the Mediterranean in spring, thus giving rise to a loop-migration pattern. Telescopic migration was demonstrated for L. s. cyanecula. Recovery data were insufficient to identify in detail the entire wintering range for all white-throated bluethroat European populations. Technologies such as the use of geolocators will play a relevant role in this scenario.