Yian Kut-Ku/Blue Yian Kut-Ku Ecology

Bird Wyverns characterized by their fan-like ear frills and large, yellow beaks. A orange stripe runs centrally down the ridge of the upper beak, and there are orange markings under each eye as well. The significantly larger and bulkier lower beak is used to dig and scoop up prey such as Konchu hidden underground. Its body is covered in orange-pink plates and beige scales while its wing membranes are deep blue in colour.

Due to their lightweight frame, small stature and hollow bones, Yian Kut-Ku can move very fast on the ground and are competent fliers. However, they are not as agile in the air as some larger Flying Wyverns so they tend to spend more time on land. Thanks to the large ear frills surrounding their ears, they have an extremely powerful sense of hearing. Although this allows them to detect and avoid potential threats, loud sounds will startle and disorient them. While they are fully capable of defending themselves against smaller predators such as Velocidrome and their packs, they are often preyed upon by larger predators like Rathian and Najarala. When confronted by a potential threat, they attempt to appear bigger than they really are by spreading their wings, flaring out their ear frills, and shriek out a loud squawking roar. They hope that this show of bravado will discourage predators but if it fails they will immediately flee the area, [particularly if the predator in question is larger and more powerful]. Yian Kut-Ku are also capable of spitting a flaming liquid in self-defense, albeit less effectively than larger wyverns which are better adapted to using their flame sacs offensively. While these fireballs are effective in killing smaller monsters, they may not successfully deter larger wyverns. Like many wyverns, they may use their tail as a weapon in combat. 

Yian Kut-Ku inhabit a wide variety of tropical and temperate habitats and are only absent from harsh environments such as deserts. Very rarely, they travel to volcanic areas, possibly to consume coal and ores to fuel their flame sac. They are omnivores feeding on ground dwelling Neopterons, worms and honey. Adults are even capable of swallowing Konchu whole when they roll up into a ball for protection. They also use their beaks to crush hard-shelled nuts and fruits. Similar to Hypnocatrice, they swallow rocks and stones as gastroliths to help them digest their food.

*During breeding season, female Yian Kut-Ku grow feathers on their abdomen which are used to keep their eggs warm. These feathers can be considered a remnant of their ancestors.* After the eggs hatch and the chicks are born the mother watches over them and feeds them honey and insects till they reach a certain age. *If the weather is favourable throughout the year, Yian Kut-Ku will breed all year round. This "population explosion" of Yian Kut-Ku may cause food to become scarce and many will die as a result though the population will gradually recover again.*

Yian Kut-Ku are closely related to Yian Garuga. However, Yian Garuga are highly aggressive towards Yian Kut-Ku. Sometimes a Garuga will take over a Kut-Ku's territory and even kill the smaller Bird Wyvern. *Female Yian Garuga will also destroy the eggs of a Kut-Ku and lay their own eggs in the nest, leaving the Kut-Ku as a victim of brood parasitism.*

Yian Kut-Ku also have a relatively rare Subspecies known as Blue Yian Kut-Ku which has similar behaviour. It is not known if Blue Yian Kut-Ku are a true subspecies that prefers to live in slightly different environments or if they are just a result of genetic mutation. Their shell is blue instead of pink and is more resistant to fire. Besides having a stronger flame sac and better aerial abilities, they are also physically stronger than normal Yian Kut-Ku especially when enraged.

Although Yian Kut-Ku were originally observed to have three toes on its feet, four-toed Yian Kut-Ku have appeared and have replaced all, if not almost all of the three-toed variants. This four-toed variant is thought to be a recent mutation.