Genetic structure offers insights into the evolution of migration and the taxonomy of the Barred Long-tailed Cuckoo Cercococcyx montanus species complex

Barred Long-tailed Cuckoo (Cercococcyx montanus) currently comprises two morphologically distinct subspecies, one resident in the Albertine Rift (montanus) and one in east and southeast Africa (patulus) in which there are migrations that are poorly understood. Based on nuclear and mitochondrial DNA sequences, we find that two specimens collected in relatively low-elevation forest in the Albertine Rift were correctly identified from plumage as the migratory subspecies whose closest known breeding area is > 800 km to the east. We discuss ways in which this unique migratory pattern could have evolved and argue that migration was gained and then lost in the C. montanus complex. Based on consistent morphological and genetic differences, we suggest that Barred Long-tailed Cuckoo is best treated as two species, one of which (C. montanus) is a nonmigratory Albertine Rift endemic.