The great blue windrunner can soar at high altitudes, making use of its long narrow wings. At low speeds, the bird requires greater maneuverability, and so deploys an additional pair of wings from its legs for extra surface area and uplift.
The great blue windrunner is a large, blue gruiform, descended from cranes, that annually migrates to the Great Plateau from southern lands to breed, 100 million AD, in the documentary The Future is Wild.
In among the clouds drifting up the Great Plateau's oceanward slope from the sea and shafts of sunlight glide the silhouetted forms of these mighty birds, with a wingspan of 9.8125 feet (3 meters).
Long, narrow wings, like those of an albatross, sweep them up towards the distant peaks at high speed, skimming the tops of the grass trees and rocky outcrops. They spend nearly all their lives in flight, soaring and drifting on upthrusts of wind blow 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 swift.
The windrunner's wings are ideal for covering the great distances between the scattered feeding sites of the Great Plateau. Descending to the sites to feed, on the other hand, calls for low speed maneuverability. For that, a broad wing is needed. To overcome this obstacle, the windrunner has developed a "second set" of wings. Feathered and muscled legs, which are normally folded back behind the bird, are brought forward when low speeds are required. When deployed, the wing-legs are held slightly upwards, improving stability. The bird's flight surface is now increased, providing extra uplift and allowing it to cut its speed and dive with great agility. Additional control is given by canards (feathery projections at each side of the head).
At 32,808 feet (10,000 meters), the thin air provides little protection from ultraviolet light - a serious threat to the great blue windrunner. The bird's metallic blue coloration helps to reflect ultraviolet light, but its eyes also need shielding. Like all birds, the windrunner has a nictitating membrane, or third eyelid. In addition, the windrunner's nictitating membranes are polarized, forming a pair of natural sunglasses. Adapted in this way, the bird uses ultraviolet light to its advantage. Females identify males by their rich patterns, which are only visible under ultraviolet light.
A female windrunner tends to her young. The birds nest high in the Great Plateau, far from predators.
The great blue windrunner is not the only resident of the Great Plateau to make use of ultraviolet light. The ultraviolet sheen of silver spiders and their great webs can attract the unwanted attention of windrunners, which swoop down to feed on the spiders that scurry about busily on the silken fibers. Windrunners definitely favor silver spiders as food, for both the adults themselves to eat as well as to feed hungry chicks back at their nests.
With plenty of food for them in a habitat with no potential predators to them, life on the Great Plateau seems safe for great blue windrunners. But there is one threat they have up here. The plateau is still moving, still restless, and sometimes it can cause great earthquakes that the windrunners always take caution of.
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