Rise of brumbles

With the advance of cold environments, brumbles have become the dominant terricolous birds of Antarctic ecosystems. Thanks to their several preadaptations to cold and optimized chewing, the group has undergone great evolutionary radiation in just a few million years: from just a single species during the Cambiocene, now it's believed that at least 6 species exist.
Although adapted from the beginning to cold forest steppes, the lack of giant brontosparrows has allowed some brumbles to spread even in temperate forest environments, such as the Reliquia forest. Here resides the giraffe brumble (Xiloraptor thanatosis), a large bird with a long neck adapted to feed on tall foliage. It can reach 400 kg of weight (880 lbs), for a height of 3.5 meters, making it an impregnable turret for most Antarctic predators. The species has a long red wattle protruding from its beak until the end of the chest, mainly used in interspecific courtship. The wattle is highly vascularized, working also as an excellent tool for body thermoregulation.
The species has a complex social behavior, with females and juveniles living separately from the males throughout the entire year. Only in September, at the beginning of the Antarctic Spring, the two social groups met, transforming the dense forests of Reliquia into an improvised scenic walkway, where males face together in order to get more females possible. Battles are usually very ritualized and rarely result in a real conflict: these "peaceful clashes" could be a self-adaptation to reduce male mortality. Due to the progressive reduction of their range, a heavy genetic loss would possibly become detrimental or lethal for this species in the long run.

Less showy but still interesting brumbles can be found in coldvanna, where the group reaches its peak of biodiversity. The big winter snowfalls of this biome prevent the extensive grazing of the big herbivores, which have various ways of getting around this problem. Stilt brumbles (Velocicrus viaticum), for example, have very elongated legs, which allow them to keep the entire torso out of the snow and reach higher branches more easily. The large beak is also used as an efficient shovel, allowing them to feed on prostrate shrubs that are located under the snowpack.
Like their lentocenic ancestor, stilt brumbles have binocular vision, allowing them to better perceive spatial depth. This adaptation makes brumbles very dangerous opponents if faced frontally, capable of hitting opponents with very targeted kicks, but unfortunately creates a large blind spot in the back of the body. This problem has been partially deceived thanks to a rather developed hearing for a bird, which is used to intercept predators before they can become a risk.
Depth perception has allowed certain brumble lineages to increase the manipulation degree of their long prehensile tongue, now used to grab branches and bring them closer to the mouth. It has the same role as a human hand and is kept for a long time outside the mouth to analyze objects in the environment. In the case of stilt brumbles, the tongue can be extroverted from the mouth by as much as 50 cm and tear branches 2 cm thick; like giraffes, stilt brumble's tongue is dark due to an overabundance of melanin, which reduces the damage of UV. In order to reduce heat dispersion and frostbite, these tongues have a higher fat content that creates a large layer that isolates internal tissues. Brumble's tongues are also keratinized but still maintain a very high haptic perception.

Unlike their "giraffe" relative from the Reliquia Forest, stilt brumbles live in a highly competitive environment: the higher abundance of mega predators has forged a deadly herbivore with an aggressive attitude against any possible invader of its territory. Even interspecific interactions can become lethal: male mortality sharply increases during the reproductive period, in which stilt brumbles engage furious battles. Their bite force is proportionally the highest of any Antarctic herbivore, reaching up to 100 kgf/cm2 (1400 PSI): besides defending themselves, this tremendous bite is very useful to break hard fruits and chewing bark, which accounts for most of their winter diet.