Imperial Skystalker

Descended from the awegull and now found across Serinarcta from the far north to the southernmost reaches, the imperial skystalker is the most successful - by numbers and by range - of the giant aukvultures of 290 million years hence. This is an apex predator without rival in the air, bowing to none and deferred to by all other fliers. With a 40 foot wingspan, and standing to 16 feet in height, the skystalker is as large as a small airplane in the air and could meet a giraffe eye to eye on the ground. It is a behaviorally flexible, highly intelligent near-sophont species (one which is close to the cusp of human-level self-awareness, but which may or may not ever reach this stage, as it is neither inevitable not inherently favored by natural selection in most cases.) It can survive in all open habitats from seashore to stormveld and from savannah to sky island. Several different subspecies and other variations occur worldwide, differentiated by dietary preferences, social behavior that represents culture, and some physical attributes, with the largest and nominate form, the central imperial skystalker (G. p. polydactylus) seen below generally favoring northern and western Serinarcta across the firmament, polar plain and polar basin. This form always breeds at height, favoring sky island summits to brood its young, and is the most strongly adapted to walk long distances and hunt on the ground in addition to in flight; it often hunts prey comparatively small compared to itself and is especially fond of eating the babies of cygnosaurs. Other subspecies may have shorter proportions of legs and neck but more robust jaws, and usually hunt prey from the air and carry it away. 

The southern imperial skystalker (G. p. impetus, meaning "to swoop") which is most common on the stormveld is its apex predator, and often breeds on the ground except for individuals living near the great seawall. It feeds mainly upon grazing animals from 100-250 lbs, which it can carry in flight. Additional ecotypes exist within these larger populations, defined by behavioral differences from each other despite having no obvious physical differences.  One of the most extreme is an obligate scavenger form of the central subspecies, and this form unusually crosses the oceans readily, making it the widest-ranging and furthest-traveling of them all. It has seemingly chosen to stop hunting live prey as a result of its ability to locate carrion instead, and in making this choice it becomes the largest exclusively scavenging animal in the world. In its unique behavior, perpetuated through animal culture, it recalls the similarly benign reaper of the end ocean age. Scavenger skystalkers may form very unusual social relationships with other species, initiated by would-be prey seeking protection from the more threatening variants of the skystalker species, as the different ecotypes do not generally socialize together.

Imperial skystalkers differ from all other aukvultures, and all birds, for having taken the evolution of powerful weight-bearing forearms full circle: they have become bipeds, walking on their wings alone. Among tribbetheres, with their most powerful muscles always located in the forearms, this has happened three times: first in the short-lived gork circuagodonts and later in sawjaws and again in seademons, both of which are still living. Similar reasons have produced this form of movement in the skystalker: its wings already power its flight and launch, and legs in the largest archangels that do not use them to glide are effectively dead weight which must be carried in the air while not aiding flight. Skystalkers overcome this hindrace by simply carrying them at all times; they are short but strong, and they are dexterous and used as manipulators as well as weapons, with long sickle-like talons which are useful to restrain prey. The skystalker has a rotated first toe allowing an opposing grasp and is also the only archangel which has acquired a fourth hind toe. This is the result of a mutation affecting limb development which mirrors the normal foot anatomy between the second and third toe, causing the duplication of digits 1 and 2 on the outside of the foot in place of digit 3, giving it two pseudo-thumbs and a zygodacyl foot arrangement ideally suited to grab prey. Because they use their feet to hunt much more than other aukvultures, their beak serrations have become relatively small. Four bill horns have evolved, perhaps for purpose of species recognition, and are slightly larger in the male. The larger top pair may also serve the same role as the eyebrow ridge in some birds of prey on Earth, shading the eye from the sun's glare while in flight.

This is a species for which generalizations cannot be made about social behavior, as individuals as well as populations differ so drastically in their habits. Some are solitary, never mingling with others outside of mating - if even then - and raising their young without help. Some are highly social, living in groups even into adulthood, often comprised of relatives, but sometimes of total strangers which meet after independence of their parents. Most often they form monogamous pairs that spend their lives together, but others will form only temporary bonds to breed and pick new mates the next year. Courtship is usually prolonged, involving a honeymoon period where potential couples spend weeks, months, or even years traveling and hunting together and developing shared calls and synchronized movements that will later affirm their bonds - but less monogamous individuals speed through this stage and take many mates and breed several times in the span that another pair may only complete their courtship rituals. Seen in almost all pairs is the most dramatic courtship behavior of all, where both parties lock talons in flight and spiral together down toward the ground, only breaking their embrace just before striking the earth. Juveniles spend as long as eight years with their parents in some ecotypes, while being driven away as young as three years old in others. The former have a higher survival rate, but also reproduce much later in life. No matter their age when they strike out on their own, newly independent skystalkers - except the most solitary individuals - will tend to seek out peers and will soon try to find a mate. 

Gatherings exist in a select few places worldwide including upon the firmament and along the hurricane coast, where every year young adults will amass in order to meet potential partners and pair off. These gatherings are usually specific to just one population, but never totally, and a few adolescents from another group are almost always present which in turn leads to a low level of interbreeding between the groups and sometimes the formation of entirely new cultures when couples come from different backgrounds and teach their own offspring a combination of customs. The large range of individuals at the gathering sites allow for different personalities to match with like kinds, as without these events, pairs which do not share habits would be more likely to develop by necessity, and individuals that don't behave the same way are unlikely to be good parents or rear many, if any, surviving young. The swinger ecotypes which don't keep mates for more than a couple seasons and which abandon their young early may seem inherently worse than the loyal pairs that keep their families together longer, but there are advantages and disadvantages to both systems. Yet a pair formed from one of each would be prone to frequent conflict, and the young might not be raised to be prepared to live on their own in time if one parent continued to baby them until its other parent left. Some can get by being independent early and others thrive if coddled until fully grown, but those in the middle often get the short end of both sticks, and end up lost and disoriented in the wider world. Factors like this contribute to the development and continuation of different, isolated breeding populations in this species - young are fitter when their parents are more similar to each other. Not since the daydreamer has a single species represented such a wide range of cultural diversity.