In spite of the mention of several colours, authors such as the British naturalist Walter Rothschild claimed that the "Gelderland" journal described the bird as entirely blue-grey, and it was restored this way in Rothschild's 1907 book "Extinct Birds". Later examination of the journal by Julian Hume has revealed only a description of the dodo. He suggested that the distinctively drawn facial mask may represent a separate colour. The British ecologist Anthony S. Cheke suggested in 1987 that in addition to size dimorphism, the sexes may have had different colours, which would explain some of the discrepancies in the old descriptions. The head was evidently blue, and in 2007, Hume suggested the beak may have been red, and the rest of the plumage greyish or blackish, which also occurs in other members of Psittaculini.