Downlings

The Downlings (genus Crinitapteryx) are a group of diminutive kiwis descended from the woolly pillbird. Their ancestor was an extreme specialist, with many adaptations for survival in small patches of harsh habitat. Today, though, these same traits have led to their success as generalists around the world. They are now almost as speciose as all other pillbirds combined, with diets and niches as varied as the biomes they live in. During the Middle Muricene, their long, probing bills shrunk, reducing their surface area to conserve body heat. At the time, this was a major trade-off; their shortened beaks were now less effective at searching the ground for isopods. By changing their behavior and preferred food sources, they've now turned this handicap into their defining feature in the present day, using it to their advantage as they rise to become the most common small-bodied birds on Apterra.

Not every downling has abandoned insectivory; the Plagueling (C. pratensis) chases Plague woodlice across the Ailuropian woodlouse-grassland. It often travels alongside its much larger maned cousins, who provide protection and an early-warning system when predators approach. It employs a very different feeding strategy than its companion; while maned pillbirds jump into the Plague, fending off hundreds of sharp-jawed woodlice as they feed, the timid plagueling sticks to the outskirts, picking off stragglers and avoiding direct confrontation.

One of the most widespread members of this genus is the Nutcracker Downling (C. confractogranus), a species whose already-short beak has become stouter, deeper, and stronger than any other kiwi's. This allows it to break open large, sturdy seeds that no other Apterran bird can eat. Even rat-grass grains, a food source previously only available to granivorous rats, are now on the menu. Luckily for the rattalopes, small birds like the nutcracker generally fare poorly against ratweasels and other rodentian hunters, so this species is uncommon on the rat-grassland despite its adaptations. Aside from this restriction, nearly every other environment is fair game; pseudoforests, woodlouse-grasslands, and tundras all support sizeable populations. 

Sugarcreepers (C. saccharostris) possess the longest bills of any downling, reflecting their basal position within the group. Their diet, however, is entirely unlike that of the original woolly pillbirds. Their ancestors migrated away from the cold wastelands they once dwelled in, settling in subtropical rain-pseudoforests around 1,700,000 Post-Abandonment. They adapted to drink woodlouse-grass nectar, slurping it up with their straw-like beaks. They never fully lost their arctic adaptations, though, and the diversification of sweetstalks has now allowed them to spread across a variety of cooler habitats. They are especially successful in cold wetland regions where their food grows in abundance, but they can also be found at lower densities wherever sweetstalks are present. Notably, a subpopulation that rafted to the Gecko Isles about 100,000 years ago has shifted to drinking the sap of tall palm-grasses.

The largest downling - but still smaller than most other pillbirds - is the Zipperbill (C. cadavoris). These are pseudoforest dwellers, though they don't discriminate between taiga, temperate, and tropical climates, for their thick plumage provides insulation against extremes of both heat and cold. Their beaks are sharp, hooked, and significantly taller than they are wide. They feed on carrion, favoring carcasses far beyond their own size. To access the meat inside, they open their mouths wide and sink the tip of their beak into the skin, pulling back with their strong legs. This produces a long, narrow gash into which they can poke the rest of their face. To avoid infection, their heads are naked, while the skin is thick to ensure too much warmth isn't lost from the exposed face. Dozens will congregate around a freshly-deceased animal, dispersing when larger scavengers arrive or when all easily-accessible food is consumed. When not searching for their next meal, both sexes can be heard singing a low, quivering song, announcing themselves to potential mates in deep, eerie tones.