Chariot

Running over the wide short-grass plains of the uplands 280 MPE may sometimes be seen a long-legged shorebird sparrowgull known as the chariot. Weighing 45 lbs, it is a large, terrestrial bird that only flies when threatened, and rarely even then, instead preferring to flee on foot from enemies at speeds over 30 miles per hour. With a robust, rounded beak lined with minute serrations, the chariot is an herbivore, feeding on short grass that grows in the hours and days after herds of thorngrazers pass by an area, and so this bird is closely associated with these animals and is constantly on the move. But as a sparrowgull, the chariot must still lay eggs and raise babies that are born completely dependant on their parents. It simply cannot make a nest while wandering with the grazers - so what is a bird to do? 

The chariot, an independent descendant of the scampering meadowbird that represents a sister lineage to the mowerbirds, gets around this by simply never putting down its egg after it is laid. Pairs of chariots hold their eggs beneath their wings, against a patch of bare skin that they pluck along the sides of their bodies, and keep them pressed there for the entire three weeks it takes them to hatch, occasionally trading the egg between them. When the chick is born, it is still carried, now more often cradled in the "hands" of the parent - actually flexible thumbs with a soft, rubbery pad that provides a secure grip. As it grows, long, hooked barbs grow from its wrist, specialized feather-like structures that help the chick to cling to its parent on its own, and by 10 days of age it has climbed onto the adult's back and there remains for the duration of its nestling period. 

Parent chariots get their name from the characteristic sight of a nestling huddled up on the back of its parent as the adults run across the grasslands, slightly resembling the horse-drawn, wheeled carts used by humans. The baby remains there for almost an entire month without ever leaving, until it may weigh 30% as much as the adult that carries it, requiring the parents trade it between them often to rest. But by keeping it on them at all times, and so using their own backs as a nest, they never leave it unattended and vulnerable to ground-dwelling threats, nor do they have to settle down and stop following the nomadic herds. They alternately give it a ride and feed it until eventually, it is strong enough to start taking short walks beside the parents and finally, around 7 weeks of age, to be fast enough to keep up with the adults and so run on its own two feet; its wing "claws" are shed shortly after. Though they have only a single chick at a time, this intensive manner of raising it is very effective, and very few chicks die before independence which is acquired around 5 months of age.