Bunjil is attested across the Kulin nation ethnographic record in several colonial-era spellings, recorded by nineteenth century observers working across related but distinct language groups with no shared orthography. The word plainly identifies the creator ancestor with the wedge-tailed eagle, but no confirmed derivation of the word itself, reconciling the recorded dialect variation into one settled origin, has been established.
What would resolve this A linguistic reconstruction of the word across the Kulin language family from a qualified historical linguist, comparing the recorded spelling variants to establish whether one original form and meaning can be recovered, or an early wordlist or grammar predating the surviving colonial-era transcriptions.
OpenHistorical and comparative linguistics of the Kulin languages, ethnohistory of south-eastern AustraliaA. W. Howitt, The Native Tribes of South-East Australia