Vocalisations, taxonomy and nomenclature of the pied boubous of eastern Africa

A vocal analysis of the duets of pied boubous Laniarius spp. across eastern Africa is presented, focusing on birds from coastal Somalia south to Mozambique. Based on the presence or absence of certain note types in duets, and variation in their structure across different populations in this region, forms of duet were found to cluster at both larger and smaller spatial scales. Vocal congruence suggests that taxon mossambicus could be conspecific with sublacteus, whereas marked differences between these two and coastal Kenyan birds confirm their previously reported genetic distinctiveness. Patterns of vocal variation broadly align with taxonomic divisions already indicated by genetic data and I integrate these to identify and define the ranges of four distinct groups: the Tropical (major and ambiguus), Ethiopian (aethiopicus), Somali (somaliensis) and East Coast groups (sublacteus, mossambicus and extralimital limpopoensis). Species rank for birds in coastal Kenya under the name Juba Boubou L. somaliensis is also proposed, and vocal data presented here support the findings of Nguembock et al. (2008) and Finch et al. (2016) that plumage criteria are unreliable indicators of taxonomy in Laniarius.