The Giant Pygmy

On islands without land predators, tiny animals can reach huge proportions... relatively, at least.

The end of the ice age was a rough ordeal for marine life, with most animals that relied on the former shallow seas dying out in the aftermath. Of the once diverse pretenguins - a group of flightless, aquatic sparrowgulls - their lineage was cut down to a single small survivor. Able to move into freshwater during the collapse, the duck-like pygmy pretenguin alone saw through the end of one ageand the beginning of another. When the world settled again, new and changed, these littlest members of their line returned to the seas and there swam off far and wide to reclaim their lost domain.

Five million years have now passed, and pretenguins have colonized the seas and the southern continent from their original northern refugia. These birds, though, aren't exactly the same as their precursors, for the world they have rediscovered is not that which their ancestors knew. A warm and tropical world, where the seas outside the nearest coasts are barren in food but the land is rich in it, and where many new islands provide safe places to avoid enemies that congregate along the productive coasts, has favored more terrestrial behavior in some. With their legs still well-suited to walk on land, unlike Earth's penguins with their hips embedded in the muscle of their abdomens, pretenguins can travel far from water where conditions allow, and an omnivorous diet means that, where predators are few, they do not need access to open water at all to survive. 

The Trilliontree Islands provide just such a place to leave the water in safety. An archipelago region of hundreds of small offshore islands, richly forested and lacking most terrestrial animal life that occupies the mainland provides the perfect habitat for a very unusual pretenguin. Towering at an immense five feet high and weighing as much as 170 lbs, the contradictory-named giant pygmy pretenguin can be found across some 15 of these islands in the south of the chain. Immense by the standards of its ancestor, it has increased in mass by almost thirty times - a veritable giant. Its appearance is still recognizable - but its behavior is very different. Though its feet are still webbed, and it can still swim very well, the giant pygmy now spends some 90% of its time on land, for the surrounding seas are filled with threats. Yet only small land predators live on the isolated islands it is found on, and by growing to its current size, it is no longer threatened by any of them. It can therefore live a leisurely life eating land vegetation which grows ungrazed by thorngrazers that cannot swim well enough to reach it. 

Though the leaves of trees and shrubs are much less nutritious than a meal of fish, it's also easier to find, and the stomach of this pretenguin has grown relative to its size by over 300% to better digest this different diet. With sturdy legs these tiny titans can travel several miles a day to find the best food plants, living alone except when males gather to attract a mate, gathering in forest clearings to display their bright plumage and sing their unusual chirping songs. Their voices, already not very nice to listen to to our ears, have become deeper and slower with their larger size, and a cricket-like buzzing has become a jarring, clacking call that sounds like hail on a tin roof. Males put all their time into demonstrating their attractiveness to a mate, and the female is left alone to nest and hatch her chicks, usually five to seven of them. She incubates her large eggs on the ground, hidden in tall grasses, and covers her eggs with leaves when she must leave them to find food.

When giant pygmy pretenguins do come to water, they now prefer freshwater ponds. They float well and clean their feathers, and may even dive to reach algae underwater. Here they consume fish eggs and insects to supplement their diet, and small minnows if they can catch them. Young chicks, with small stomachs and short stature, spend more time along the water under the supervision of their mother and eat more animal prey - they are faster, too, and better at catching live fish, and this fuels their growth into their eventual herbivorous adult form. 

This species occasionally makes sea crossings, seemingly at random, usually when populations on one island become too high and the vegetation becomes depleted. In these conditions, younger birds will be harassed and chased by adults until they are pushed to the shoreline and must seek food elsewhere. They may then eat seaweed and seagrasses, but they are now poor divers with too much body fat to spend long underwater without floating back up, and so they tend to swim off in search of other lands. While many likely perish on the open sea, occasionally enough reach another island to colonize it and reproduce, so that the range of the giant pygmy pretenguin continues to expand across the archipelago.