Serina: A Natural History of the World of Birds

The Cryocene: 50 - 75 million years

50 Millions Years PE

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50 million years have now passed since the introduction of the canaries. The world has already seen significant changes since its colonization, with the Tempuscenic era ushering in several tens of millions of years of relatively cool climactic conditions and the spread of desertification. By fifty million years PE, the climate is the coldest it has ever been, as the Tempuscenic era transitions into another, the Cryocene. Serina has now become a snowball moon, meaning that at least half of the moon's surface, at any given time through the year, is below the freezing point of water and covered in either ice or snow. The extreme north and south pole have become uninhabitable for most life at any time of year, but from the tropics to approximately halfway to either pole, conditions remain seasonal but habitable, reaching warm and mild levels through the summer and into the fall. The landmasses of Striata, Whalteria, and Karii have collided to form a single continent in Serina's east which straddles the equator, with arms stretching both north and south into the frozen zones of either pole. In the west Anciska has seperated into a northern and southern continent, the northern moving into the arctic circle and the southern colliding to form a southerly land mass with Stehvlandea, the northern portion of which rests on the equator. The Kiran islands rest nearly at the moon's prime meridian - an ideal location for life on the cold world today.

Increasingly cold climactic conditions have favored the refinement of adaptations that began to develop on Serina in the beginning of the tempuscenic; better able to reproduce in environments where winters are harsh than other birds, the live-bearing aardgeese which incubate their eggs in their bodies have come to dominance over most environments away from the equator. No longer tied down by the need to keep an egg warm, they can breed in the early spring before the snow has fully melted, when any naked egg would be at a high risk to freeze solid if left for more than a few moments uncovered. Herds of grazers now migrate seasonally from one hemisphere to the other, avoiding the winter chill, some always following the summer sun, while the group which was once adapted generally as large herbivores has begun to dabble with forms specialized for other niches and diets. The original cursorial predator canaries, the skykes and their kin, have become relegated to the tropics, while newly-evolved carnivorous aardgeese have taken their place where winters are long. They have become increasingly diverse in size, both larger and smaller - one group in particular, native to the frigid north, has become quite small and increasingly adapted towards burrowing to survive the cold.

Among the flying birds evolution continues to produce forms convergent to unrelated Earth lineages and poor-flying ground birds, intelligent generalists similar to crows and jaws, and predatory falconaries of many sorts, including owl-like nocturnal predators, are abundant with ranges that span the globe. Even after fifty million years, however, many canaries retain primitive and conservative body plans. Just as the lizard still resembles the earliest diapsids and the opossum is a close doppelganger to the earliest mammals, the generalized "finch" niche is likely to last through all that Serina has to throw its way.

One of the major innovations in the birds to appear by the start of the Cryocene is the evolution of multiple aquatic avian groups, from both semi-aquatic duck-like ancestors which are still abundant worldwide as well as from more airborne predatory groups, such as the fishing falconaries that converge upon auks. The pelicanaries, a flightless group of cormorant-like seabirds which developed the behavior of incubating their eggs at sea within their throat pouches rather than in nests on shore, have speciated significantly. Adaptations evolved originally to avoid competition for on shore now had multiple benefits - like the aardgeese on land, practicing a form of internal incubation would prove advantageous in cold climates, allowing the pelicanaries to exploit polar seas for food without to migrate to warmer environs to nest. Freed from the need to come ashore and sit on their eggs, they are no longer constrained to relatively small sizes, and their representatives now include the largest birds ever to live.

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Serina's fish have by this time reached a diversity equaling that of Earth and in all of them, their specific ancestry is not apparent. Unlike the majority of Earth's fish, however, the majority are still live-bearing. The largest among them have evolved placentas to nourish their young in utero and begun to develop complex social behavior. The descendants of semi-aquatic mudwickets have moved increasingly into terrestrial habitats; though generally intolerant of dry conditions, they've cut their ties to open water almost completely and many species have evolved to live entirely on land in moist environments, such as forest floors and jungles. Most species burrow to some extent. The ability to hibernate has evolved, allowing survival in even quite arid locales and regions with harsh winter temperatures.

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The flora of a snowball Serina has adapted as much, if not more than, the fauna. The dominant floral group across Serina today is bamboo, which has speciated quickly in increasingly specialized mutualistic co-evolution with ants and spread again across the planet after an initial decrease in range. The symbiosis between ants and bamboo plants had now produced a floral "revolution" comparable to the appearance of the first flowering plants, as the bamboo is able to colonize anywhere it likes, armed with armies of biting insects that protect them from both herbivores and competitors, by attacking browsing animals and cutting down competing plant seedlings around their host plants that could steal their nutrients. Multiple evolutionary arm's races have now begun in earnest, with herbivores evolving armored faces to protect against ant bites when feeding on both ant-guarded plant varieties and their competitors which have evolved a myriad of defenses from the leaf-cutter ants. Some sport billions of microscopic cutting blades of silica on every leaf that turn formerly succulent foliage into tufts of knives, while others develop elaborate furry coats of spines to guard their tissues against ant attacks. Serina is no longer an idyllic grassland world - now the plants themselves fight not only the animals that once fed freely upon them, but each other too. Sunflowers adopt a new form in the face of harsh, dry climates - they lose their leaves and develop swollen tissues. The sunflower cactus spreads across Serina's drier parts and does particularly well in the harsh north. Where on Earth grow conifers in the boreal forest, Serina's cold woodlands are predominately of tall cactus lookalikes, descended originally from a common garden flower. Their thick barrel-like shape resists drying winds and thick coats of furry spines double as defense and insulation. Their ancestry can now often be betrayed only when they bloom.

The leafcutter ant lineage, once relegated to the tropics, now occurs everywhere on the planet where plant life occurs, wintering in special hollowed-out tissues within the stems and nodes of their symbiotic bamboo homes, where they're able to stay warm through the winter and safer from predators. In addition to lodging, the bamboo plants may also pay their defenders with food in the form of nectar secreted from within its stems, though many species now are no longer farming fungus and have become predatory, eating pest insects that harm their host. The pinnacle of their interdependence has now been reached, and no longer do new queen ants have to search out seedlings of their host trees to start a new colony. Reproduction between plant and insect has become timed so that the tree's seeds ripen just as the new queens take flight to start a new life; when she leaves, each female takes with her a single seed and plants it herself. She selects a sunny site of newly exposed soil near a riverbank or where a fire has cleared the land and buries the seed, constructing a small tunnel system beneath it where she begins to lay her own eggs. Until the seedling is large enough to move into, they live beneath it and guard it from all comers, bringing fertilizer to its roots in the form of the remains of small prey the workers bring down into the burrow and their own droppings. When the plant is large enough the colony moves into it, typically just as autumn approaches, and there they spend the winter. Colonies of ants may inhabit the same bamboo plant for decades, and the queens are extremely long lived.

The proliferation of ant diversity has not gone unnoticed, and ant-eating animals have evolved in many different clades, specialized to make use of this resource other animals shy away from. A battle from many fronts between ants, birds, and plants rages on.