Kiwis on Apterra, like their earthly ancestors, live in the shadows of the dominant rodents in their habitats. Despite all the rapid adaptations seen during Muricene's previous age, avian life on this planet is once again in a state of decline. With the rats diversifying further with every passing generation, the various Apteryx populations now find themselves pushed to the fringes more and more. Generalists have become specialists, while specialists have either entrenched themselves deeper in their niches or found themselves outcompeted by their murid counterparts. Only in a select few environments do kiwis occupy major roles in their ecosystems - islands, mountains, and other far-flung habitats provide a welcome refuge, as does the metaphorical isolation of certain ecological niches that rats haven't yet stumbled upon. For instance, the long bill of the ancestral kiwi permits a probing behavior in some species, a behavior that's impossible for the mammalian snouts of their rat competitors. As such, isopod-eating kiwis find a place for themselves in many environments; indeed, they are often the only birds that can survive certain rat-infested pseudoforest biomes around the equator.
The well-connected tropics of Abeli and Loxodia are home to Apteryx proborostris, an insectivore especially well-adapted to plucking Armadillidium arborealis and other similar woodlice from their woodlouse-grass homes, though it retains the ability to dig and sift through soil and debris to find ground-dwelling varieties. Thousands of miles away, Apteryx dendroquassor lives in similar climes across the west of Ailuropia. Due to the palm-grasses' dominance on this continent, this species almost exclusively eats arboreal woodlice, while another kiwi, A. crustifodiens, spends its time scouring the earth below.
Across the northern edge of Panapterra, the extensive temperate belt permits the survival of more generalist forms, albeit at very low population densities. Apteryx pseudosylvestris, the sister taxon to A. grandis, lives across the entire area. Theoretically, an individual of this species could be born in the far northwest of Ailuropia, travel to the Ailox region, then turn southward to traverse the northern portions of the swampy coastline. Heading across the land bridge, it could proceed to cross the entirety of Loxodia's northern mountains, reaching the eastern shores of that landmass over 20,000 kilometers from its starting point, all without ever leaving its preferred temperate pseudoforest environment. Of course, no single kiwi has ever made this trek, but the interconnectedness of its habitat has created a continuous gene pool between individuals who live continents apart. As a result, while genetic diversity is high in this species, that variation is uniformly spread across its range. It does not, like its cousin, form massive long-term herds; in fact, it is solitary outside the mating season. Couples follow a serial monogamist breeding pattern, being quite attentive to their mates throughout the chick-rearing process but forgetting each other by the following year.
The more fragmented pesudoforests of Abeli do not boast an analogous species, as there are no contiguous patches of habitat large enough to avoid extirpation by rats. The savannas of that continent, however, are still the home of burrowing kiwis, which have now diverged into the species Apteryx subterraneus. Their underground nests are more extensive now, consisting of a long passageway that terminates in an almost entirely enclosed chamber where the egg can remain safe. The burrow-dwelling isopods are still going strong, now actively cleaning their hosts throughout the incubation process. When the chick hatches, the pill bugs work quickly to consume any spilled albumen, helping to mask the scent that might otherwise attract opportunistic rats. The kiwis live on dry grasslands on both sides of the mid-Abelian mountain range, though predation pressure has recently forced them to stop making long-distance aboveground journeys. The two populations are already beginning to diverge; the western subspecies is larger, for instance, and its counterpart has a slightly longer neck and legs in order to shed excess heat in its hotter environment. Both have lost the sexual dimorphism seen in the first burrowing kiwis, as females who can forage for isopods underground are less likely to be killed by predatory rats.
Sub-Abeli is a true wasteland for kiwis; the dense fields of rat-grasses promote such high predator densities that any Apteryx species would be hunted to extinction. The subcontinent is, in fact, the largest portion of Apterra entirely free of birds at this time. The islands south of these lands would be a perfect home for kiwis, free of all rodentian threats, but to get there they'd have to cross hundreds of kilometers of hostile territory. North of Abeli, however, a different island home supports extensive kiwi populations. The Gecko Isles, though named for their reptilian tenants, are equally a refuge for their several endemic Apteryx species. The island-dwellers of the Dawn Muricene have given rise to the Seawis, a collection of semi-aquatic ratites dwelling across the archipelago. Apteryx anatopes is quite at home in the water, spending much of its day out at sea fishing for Gambusia. Lacking waterproof feathers to trap a layer of air, it stays afloat using an extensive patchwork of internal air sacs. It also possesses no means of excreting the excess salt it consumes while foraging, a handicap that necessitates regular trips into rivers and lakes, where it drinks copious volumes of fresh water to compensate.
Further inland, the speedy Apteryx gekkovenator patrols the slopes. This species's diet is composed of nearly 80% lizards, supplemented with the occasional seed, isopod, or fish. Apterra's true woodlouse-eating champion, though, is its close relative A. recurvilingus, a small and timid creature that prefers to keep to the shadows of the islands' dense pseudoforests. The reason for this becomes obvious when an Apteryx apterovenator approaches. This is the only fully carnivorous kiwi yet to evolve on Apterra; indeed, it's the only thing on the isles capable of eating prey over a hundred grams in mass. Its sharp bill pierces through flesh easily, and smaller prey may even be skewered and tossed from the ground. It rarely hunts adult kiwis, though, for even the smallest are still a bit too large to be easily taken down. At the moment, though, an ongoing drought has led many of the hunters to resort to desperate measures, a fact the smaller birds are acutely aware of.
Following a mountain stream down into the lowlands, a gallery pseudoforest emerges, composed of large basket-grasses, paddle-grasses, and the occasional skystalk. The lush canopy provides shade and protection from the elements, and, all in all, creates the most comfortable environment in the entire archipelago. Here, kiwis of all species raise their young, vying for the best nesting sites and settling down with their partners. Predator and prey put aside their differences here, as geckos are so abundant in this habitat that the more difficult avian prey wouldn't be worth the effort for any hunter with half a brain. This peace does not last; once the young hatch, there's a race back to the open areas. Whoever gets to the best land first will find success throughout the following year, and the stragglers will run a serious risk of starvation.
Returning to the mainland, the Loxodian interior boasts Panapterra's highest density of kiwi species. The massive ten-year desert, once only home to rats, now sees regular visits from A. aridiphilus, a scraggly-looking savanna-dweller happy to take advantage of the irregular rainy seasons. Unlike the local rodents, this species does not see a significant population decline during the in-between years, but instead disperses throughout the continent's lowlands where it can establish a more permanent population. The Dawn Muricene's mountain-climbing birds are no longer extant in their original Abelian homeland, having been wiped out by predators millennia ago. However, the woodlouse-grass-dominated slopes of the mid-Loxodian mountains provide far less food for local rat populations compared with the rat-grass-covered hills of Abeli. As a result, the alpine Apteryx lineage has migrated to this region and lives on to the present day, forming the species A. petroscandens. These feed on abundant isopods, plucking them from the stems of the short, scrubby skystalks they cling to. The woodlouse-dispersed grasses common in this range 80,000 years prior, while not true woodlouse-grasses (being, in fact, more closely related to the spiny-grasses), also benefit from this arrangement, as their seed-dispersers are plentiful enough to ensure their survival despite grazing pressure from the local kiwis. These false woodlouse-grasses are known as Bouteloua pseudarmadillidiophilus, and they make up the short turfgrass layer beneath the taller skystalks.
On the banks of the algae-choked inland sea, the western coast of Loxodia is characterized by a unique subtropical pseudoforest ecosystem. In a sense, it resembles the temperate regions surrounding the continent's northern mountains, with palm-grasses and giant skystalks forming a scattered overstory above a carpet of smaller basket-grasses, rat-grasses, and basal turfgrasses. The canopy here is, however, quite denser than its northern counterpart. This is primarily due to an abnormality in the local palm-grass subspecies, which is prone to branching out into several stems beyond its fifth year. This creates a fuller, bushier plant, increasing its spread year after year without becoming any taller than its single-stemmed counterparts. As palm-grasses have relatively large seeds without dedicated dispersers, new generations often crop up around their mothers, forming small groves that provide the perfect habitat for Apteryx furtivus. This half-kilo herbivore lives most of its life in these thickets, which are further fortified by the presence of rat-briars (Bouteloua acufolia), an odd rat-grass species that attempts to play both sides by receiving energy-dense manure from the kiwis while having its seeds spread by rats. Unlike most of its kin, this plant does not produce seeds continuously, stopping for around two months during the birds' breeding season. This prevents it from attracting rodents who'd eat the eggs and chicks of the rat-briar's vital nutrient source. Further north, where the protection of rat-briars and bushy palm-grasses is absent, A. xanthopteryx darts cautiously across the pseudoforest. Many rats threaten it here, pushing this species to be far more cursorial than its sister group.
Just east of Loxodia's central mountains, a rat-grass savanna dominates the landscape. While not directly in the mountains' rainshadow, this region is far enough from the sea that only a modest amount of precipitation reaches it. Drought-tolerant rat-grasses are the most common prairie plants here, along with a smattering of reed-like basket-grasses wherever streams cut through the loose soil. In all, the environment here is remarkably similar to that of sub-Abeli, and one might expect to see no kiwis here at all as a result. One group of survivors, though, refuses to be ousted from the area. Apteryx nidivenator, while generally omnivorous in its diet, has a particular taste for young rats, regularly raiding unattended nests and using the protein gleaned from the pups as fuel for rearing its own chicks. As a result, rats of the nomadic group, with their precocial young, have fully outcompeted their sedentary cousins, who found themselves all too often losing their offspring to the very birds they'd once preyed upon.
This reflects a trend that will become more and more prevalent as Apterra's ecosystems mature: rats will soon begin to find themselves no longer guaranteed the upper hand against their avian rivals. While the rodentian golden age will continue for a few million more years, the rat-friendly days of the Muricene are numbered.