On a quiet summer morning in South Anciska, 220 MPE, a troop of monkjacs are leaving the forest's edge to graze in a wet, low-lying meadow. These four-legged, placental birds are an interesting branch of the ornkeys, which have become accustomed to spending their lives on the ground rather than in the jungle treetops. Their arms and legs have become longer, giving them a high vantage over the tall plains grasses to watch for predators, and with a height of almost 6 feet at the head, they can see quite far indeed. They often feed by plucking shoots and leaves with their arms, then lifting the morsels to their beaks with their two grasping digits, to reduce how often they must dip their heads and become vulnerable to ambush attacks. When walking, they bear weight on the knuckles of their "fingers", protecting their sharp, hooked claws which are as useful for self defense as foraging - a predator that is not very cautious can find itself quickly scratched across the face, possibly losing an eye in the process.
The monkjacs are social creatures, and a pair of dull-colored females are closely accompanied by a larger, dark-backed male whose role is to protect them both from enemies as well as rival males. He periodically barks out a loud, harsh call, which serves to keep other males away. If he is challenged, he will fight over his harem, the two males standing on their hind legs and shoving one another until one succeeds in pinning down the other. For now, though, this male is unchallenged. Life is peaceful for the family, and a single banded chick jumps back and forth between the adults in the group. It does not matter which of the two is its mother, for both will shepherd it close if danger threatens, and neither will directly provide it any food. Instead, nibbles grass and pecks at small insects stirred up by the stepping of its elders, quite independent from infancy. Though already nearly two feet high, this young individual is just five days old. The loss of flight capacity in its species allowed for longer pregnancies, and his entire larval development occurred before birth, including pupation, all while remaining tethered to a supply of nutrients from the placental connection with his mother. He was his mother's only offspring, a trade-off for being so large and capable immediately after birth, compared to other placental birds which produce larger litters of relatively smaller chicks.
The adult monkjacs are always alert for danger, their wide sideways-facing eyes scanning the horizon for any movement which could indicate a predator's sneaky approach. The chick, though, is less cautious. Attended by the adults, he has less need to be wary, and so he is taken by surprise as a pair of huge, elegant songswans - named for their extraordinarily loud, melodic warbling call as they fly - careens almost silently down from the sunlit sky and comes to a running stop in the meadow just beside him. With wingspans of 18 feet, they are another member of the placental bird family, of a clade called archangels. Fortunately for the little ornkey, they are docile plant-eaters, and thus the adult monkjacs gave no call of alarm to alert him. Though he takes a tumble in his fright, he soon regains his composure, though remains close by his father as the troop moves off away into the grassland to feed. The archangels, too, have come here to eat. Almost ten feet tall, they lower their heads alternately to pick a mouthful of grass, each one watching out for the other as they fill their bills. Despite their imposing size, the songswans are a more primitive sort of placental bird than the monkjacs, more alike their common ancestor, the gullgling, in that they can only afford to hold their developing young internally for a limited time in order to remain light enough to fly.
These two are a mated pair, and though they have little outward dimorphism, the female is currently pregnant. In just a few days, she will depart from her partner and join hundreds of other females at a nearby nesting ground along a river where last fall's floodwaters have now left behind an expansive stretch of open sand ideal for the incubation of her young as they pupate. She will dig a nest, and there give birth; the chicks will remain there, gently covered with loose sand and kept warm by the sun, for the next 90 days. Then they will break free of their cocoons, dig their way up through the ground, and take flight together as a flock. By then their mother will be long gone - unlike the monkjac chick, they may never meet her. Their lives are in their own hands from the very beginning. For the next five years they will fly free, following swarms of insects and later seasonal flushes of green grass. Though both groups are specialized grass eaters, the archangels have advantage over the monkjacs in their ability to disperse far and wide to find new food sources if one region becomes less productive. In addition to their primary wings, in adulthood they acquire a second set of "gliders" as primary feathers sprout down the length of their legs. Though their legs cannot flap as their true wings can, these gliding wings catch updrafts, enlarging their airfoils and providing additional lift once off the ground. Soaring this way, they can cross continents on hardly any energy at all, sometimes undertaking migrations from one side of the world to another and back again each and every year. Though the hind wings are less flexible than the fore-ones, they can fold up neatly when the bird lands, and an additional cartilage rod growing off the ankle, which can be extended or pulled tight against the leg, functions to control their spread whilst in the air.
As the songswans graze and the monkjacs disappear over a nearby hill, a small, unassuming tribbethere emerges from a shady glade of bushes. A set of large, cropping teeth at the front of its jaws betray its ancestry - this is a molodont, a lineage which has over the last twenty million years spread over all of the world, but largely remained small in comparison to the dominant megafaunal birds and the related predatory canitheres. This particular molodont does not appear outwardly unique from any other, being around as big as a hare. It, too, eats mainly grass. The tip of its tooth-beak is narrow and blade-like, an effective cutting tool, while the back of its teeth are wide and suited to chew. With each bite, its wedge-shaped jaws pull in grass, crush it for swallowing, and repeat in an efficient, wheel-like chewing motion not seen in any other grazing molodonts. This lets it eat even very hard, spiny vegetation that other animals like the placental birds avoid. As long as the dominant vegetation on the grasslands remains soft, delicate grasses, those birds will face no immediate threat from this new molodont, the circuagodont, or wheel-jaw.
But with plant communities in the Pangeacene no more static than those of the animals, there is change on the horizon. The monkjacs soon return to shelter and the songswans fly off to new pastures as a storm brews on a distant sky.
The hungry molodont carries on.