Incongruences between ratite phylogeny and Gondwana geological history indicate the presence of ratites in their current locations is the result of a secondary invasion by flying birds.[14] It remains possible that the most recent common ancestor of ratites was flightless and the tinamou regained the ability to fly.[15] However, it is believed that the loss of flight is an easier transition for birds than the loss and regain of flight, which has never been documented in avian history.[7] Moreover, tinamou nesting within flightless ratites indicates ancestral ratites were volant and multiple losses of flight occurred independently throughout the lineage.