 Sea levels were lower during the Pleistocene , so it was possible for species to colonise the Mascarene Islands from other areas . Although little is known about most extinct parrot species of the Mascarenes , subfossil remains show that they shared common features , such as enlarged heads and jaws , reduced pectoral bones , and robust leg bones . Hume supported their common origin in the radiation of the Psittaculini tribe based on morphological features and the fact that Psittacula parrots have managed to colonise many isolated islands in the Indian Ocean . According to this theory , the Psittaculini could have invaded the area several times , as many of the species were so specialised that they may have evolved significantly on hotspot islands before the Mascarenes emerged from the sea . 
