sentences:  Some authors consider this bird to be part of a species complex with "Cinnyris afer", where it joins Ludwig's double-collared sunbird ("Cinnyris ludovicensis") and Prigogine's double-collared sunbird ("Cinnyris prigoginei").As with other closely related species, each inhabiting different locations, there are subtle similarities and differences between the local populations, and their taxonomic treatment depends on the views of the taxonomist.The sunbird is a large-sized species.