Biometrics and sub-specific identification of white-spotted Bluethroats (Luscinia svecica cyanecula and L. s. namnetum) during autumn and winter.
Detailed analyses of the biometrics of white-spotted bluethroats captured in the Iberian Peninsula and sub-Saharan Africa show that previous criteria for diagnosing subspecies are inadequate. This deficiency seems to result from feather wear during the breeding period and so new criteria are proposed for the migratory and wintering periods. Foreign recoveries in Portugal indicate that the new crit