superprecocial:
In biology, precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. …
Extremely precocial species are called “superprecocial”. Examples are the Megapode birds, which have full flight feathers and which, in some species, can fly on the same day they hatch from their eggs. [Wikipedia]
Seen in “Flipping the birds,” , NewScientist (4 March 2017, paywall):
Where the eggs hatched is also odd. We know that adult opposite birds mostly lived in forests and had feet made for perching on branches, but fossil nests show they began their lives in eggs partly buried in soil. The ground-dwelling bush turkeys, or megapodes, of Australia are a modern example of this. Their chicks dig their way out of the ground after hatching, a bit like turtles. Megapodes are also the only living birds with superprecocial young, says David Varricchio of Montana State University. “[They] are completely independent of their parents. They hatch and run off on their own.”
