 The 2002 study indicated that the ancestors of the dodo and the solitaire diverged around the Paleogene @-@ Neogene boundary . The Mascarene Islands ( Mauritius , Réunion , and Rodrigues ) , are of volcanic origin and are less than 10 million years old . Therefore , the ancestors of both birds probably remained capable of flight for a considerable time after the separation of their lineage . The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae , which indicates the flightless raphines had ancestors that were able to fly , were semi @-@ terrestrial , and inhabited islands . This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia . The lack of mammalian herbivores competing for resources on these islands allowed the solitaire and the dodo to attain very large sizes and flightlessness . Despite its divergent skull morphology and adaptations for larger size , many features of its skeleton remained similar to those of smaller , flying pigeons . Another large , flightless pigeon , the Viti Levu giant pigeon ( Natunaornis gigoura ) , was described in 2001 from subfossil material from Fiji . It was only slightly smaller than the dodo and the solitaire , and it too is thought to have been related to the crowned pigeons . 
