A successful new group of birds have evolved in this era in which the legs are adapted as flying surfaces, so making four wings. The most spectacular example is the great blue windrunner, a striking site with its iridescent blue plumage and a 2.5m wingspan.
They spend nearly all their lives in flight. Their extra set of wings improves their soaring and drifting on upthrusts of wind blown up from the sea and deflected from the mountain slopes.
The great blue windrunner needs only short periods of rest. As it reaches the highest peaks, it switches to glide and naps for a few minutes, like a human-era swift.
A thin, transparent layer of darker skin can be slid across the eyes to protect them from the piercing sun like a pair of sunglasses.
Feeds by catching giant spiders and other insects.
Builds a nest high in the mountain peaks of the Great Plateau and lays eggs.