The bird that has lost everything

After their biodiversity peak in the early Biancocene, brumbles began a slow but steady decline, reaching their lowest point 90 million years AP. These versatile birds were able to thrive in the large coldvannas and forests of Antarctica, but now, with so little habitat remaining, they are officially on the verge of extinction. Only one species remains, the snow brumble (Niviornis relictus), which resides in the northernmost areas of the Sanctuary Peninsula.

Ecology

The snow brumble lives in the remaining shrubby areas of Antarctica, from the northern edge of the Follia Plateau to the more "habitable" shrub tundra biome. While capable of feeding partially on forbs during summer, most of its diet consists of the foliage of doorpeas and cancerthorns. Although some prostrate and erect shrubs are found even in the grassy tundra, colder temperatures and the trampling action of tramplerats and trenchcrawlers significantly reduce the density of these plants, making them insufficient to support a large and stable population. When these two large vertebrate species become abundant, snow brumbles are among the first large vertebrates to decline and disappear, not for niche exclusion but for habitat degradation.
Due to their modest size (weighing just 30 kg), snow brumbles are threatened by several predators, both terrestrial and aerial, even in adulthood. As a result, snow brumbles are one of the few Antarctic "megafauna" species that still display complex anti-predatory behaviors, depending on the size and type of predator. Thanks to their strong legs, they usually defend with kicks from small-medium sized carnivores like ottofoxes and bachisaraptors, while with larger opponents they usually try to flee inside thickets or on rocky areas.

The species exhibits marked sexual dimorphism, with males being larger and darker, while female are smaller, lighter and possess a spotted plumage in the dorsal part. Both sexes have two unusual bone elongations in the mandible that function as tusks. These tusks likely developed initially for sexual display but are now also useful for breaking branches, intimidating predators, and providing more space for powerful jaw muscles to better grind vegetation. Females also have these tusks, but they are much smaller than those of males. Tusks can be made up to 50% of keratin in order to reduce its weight, with the bone part being a small stump, like in goat horns.

The Past

Snow brumbles are a hybrid species between the webrumble and the alphabetabrumble (25% webrumble and 75% alpahbetabrumble heritrage). These species maintained a hybrid zone that kept them genetically distinct until a few million years ago. The two species occupied different niches with some overlap, but increased habitat homogenization and the reduction of their habitat range forced them to live closer together, resulting in the creation of the snow brumble through hybrid speciation. Although initially having a small range, this hybrid species had great genetic diversity due to its mixed heritage (a case of hybrid vigor). However, the worsening climatic conditions after the Continental Crisis caused a significant collapse in the snow brumble’s range, reducing it to just 20% of what it was a million years ago. With a fragmented population numbering few tens of thousands, the brumble dynasty faces extinction for the first time.

The Present

Snow brumbles now inhabit only a small portion of the continental Sanctuary Peninsula. A small subpopulation exists in the west, while a larger population is found in the east, primarily around the Neve Delta and the Seamount. In total, this population likely numbers fewer than 10,000 individuals.
Almost 80% of the entire snow brumble population is found in the insular environment of the Pacific Rim. They reached some of the largest islands by dispersing across sea ice during winter in search of new food sources. The migrating snow brumbles discovered new resources and predator-free areas, allowing them to proliferate rapidly and at higher densities.
However, despite the apparent population increase, the situation is far from rosy. Only a handful of brumbles initially colonized this fragmented insular archipelago, leading to several genetic problems. The insular population suffers from heightened susceptibility to diseases, infertility issues, and overall reduced fitness. Despite the apparent increase in range, the Pacific Rim has become a dangerous ecological trap for snow brumbles.

Meanwhile, the slow and steady cooling of Antarctica, coupled with the expansion of sub-optimal habitats like the grassy tundra, is sealing the species’ fate. If the ice were to expand just 2° further in latitude, the expansion of colder environments and the spread of tramplerats and trenchcrawlers would lead to the complete annihilation of the shrub environments in continental Antarctica, along with the remaining populations of brumbles, ramos, and furagos. Their future is on the razor's edge.