Alex J. Berryman

Abstract. The maroon oriole Oriolus traillii (Vigors, 1832) is a polytypic songbird found in South and Southeast Asia. It has traditionally comprised four subspecies (traillii, robinsoni, ardens, nigellicauda), but recent molecular data have found some of these to be paraphyletic with respect to the silver oriole O. mellianus Stresemann, 1922. Here, I review the morphological differences between the four taxa, and their respective distributions, using 66 museum specimens and 745 photographs. Significant plumage and mensural differences are congruent with molecular data and suggest that the maroon oriole should be considered three species: (i) maroon oriole O. traillii (Vigors, 1832), (ii) Dalat oriole O. robinsoni Delacour, 1927, and (iii) red oriole O. ardens (Swinhoe, 1862); in the absence of any consistent phenotypic differences, subspecies nigellicauda should be synonymised with ardens. Although previously considered to be more widespread in South-East Asia, O. robinsoni is found here to be restricted to the Dalat Plateau of Vietnam and adjacent south-east Cambodia. Oriolus ardens is common in Taiwan and nearly extinct on Hainan, but its status in continental Asia remains somewhat uncertain. Although other authors have suggested that O. ardens may be of conservation concern, I find no evidence that any of the three species are threatened.

Key words. taxonomy, songbird, citizen science, Indochina, morphology, conservation

Read article here: RBZ-2026-0047