Megapode the surface of the mound, lying on their backs and scratching at the sand and vegetable matter. Similar to other superprecocial birds, they hatch fully feathered and active, already able to fly and live independently from their parents. In megapodes superprecociality apparently evolved secondarily from brooding and at least loose parental care as more typical in Galliformes, but their reproductive model has been compared to various extinct maniraptors, implying that supreprecociality was common if not ancestral in early birds. Eggs previously assigned to "Genyornis" have been reassigned to giant megapode species. Some dietary and chronological data previously assigned to dromornithids
Tongan megapode in Polynesia. Similar extinctions occurred in Fiji and New Caledonia, which apparently had three species in prehistory. The species itself once had a more widespread distribution, occurring across most of Tonga, Samoa and Niue. The cause of all these extinctions and declines was the arrival of humans on the islands, and the associated predation on adults and particularly eggs, as well as predation by introduced species. On Niuafo'ou the small human population and remoteness of its habitat probably saved the species. The only megapode to survive human arrival in Western Polynesia, "the megapode nesting grounds were carefully controlled by the