Yian Kut-Ku is a Bird Wyvern introduced in Monster Hunter. It is known to inhabit forested areas and can be encountered at all ranks.
The Yian Kut-Ku is characterized by its large, fan-like ears that unfurl when excited. They have a large, yellow beak with a pink stripe running down its length. The lower jaw of this beak is significantly bigger than the top jaw. Yian Kut-Ku's body is covered in orange-pink plating and beige scales. Its wing membranes are a deep blue and its eyes are a bright yellow. These wyverns are small and relatively light, making them quick and agile. They have an extremely powerful sense of hearing, thanks to their large ears.
Yian Kut-Ku is capable of moving at high speeds thanks to its light weight and small stature. It it also able to produce flaming projectiles which can be shot from the mouth at attackers.
A somewhat temperamental, skittish, and inquisitive wyvern. Yian Kut-Ku have a tendency to want to appear bigger than they really are by spreading their wings, flaring out their ears, and squawking loudly. They are generally insectivores, preying on Konchu and other Neopterons as a main part of their diet.
The name "Kut-Ku" may come from the word "cuckoo" for its bird-like characteristic and appearance.
There is a quest called "At Birds Hill..." which requires players to fight an extremely small Yian Kut-Ku at the Forest and Hills zone, which is most-likely a young Yian Kut-Ku. It has a different voice due to its miniscule size, yet its fireball attack increases in power and explosion radius, this may be because it doesn't have very good control over its Flame Sac.
Yian Kut-Ku can be sometimes be seen drinking from the ponds in Areas 9 and 10 of the Forest and Hills.
The Yian Kut-Ku has 4 toes while in previous generations, it had 3 toes.
Yian Kut-Ku will prey on Konchu to regain stamina.
Yian Kut-Ku is now capable to release 2 fireballs instead of 1.
While low on stamina, Yian Kut-Ku won't be able to shoot fireballs, and its beak will get stuck in the ground when it performs its pecking attack.
Yian Kut-Ku can be a pet, its favorite foods are insects and worms.
Yian Kut-Ku's ears can be broken twice.
Yian Kut-Ku's ears will fold back when affected by a Sonic Bomb and are not used as a weakness sign.