Doombirds

Doombirds (ドゥームバード, Doūmubādo) are Magical Beasts, a large number of them residing on the Lost Forest near the Athelney School of Nen and Abilities.

Biology
Appearance-wise, Doombirds are very large birds, with the largest ones being able to reach up to 120 cm of length and 14 kg of weight, though most remain at around 90-95 cm of length and 6 kg. They have bald heads, large wings, sharp claws, and also black feathers all over the rest of their body.

Behavior
Doombirds are scavengers, meaning they eat dead animals, whether those were killed by them or not. They are said to be quite intelligent and able to adapt to different kinds of situations easily; they are also gifted with enhanced vision since birth and great memory. A proof of their wit and ingenuity is the fact that they are fully aware of the fact that despite their size and sharp claws, they are relatively weak, especially if compared to other creatures, and thus, develop counter-techniques to make up for this weakness. To get food, Doombirds adopt many different behaviors to somehow lure their prey into a situation where their life is in danger; after their victims die, they eat their bodies. For this reason, they are also known as "Mimic birds" or "Actor birds".

Even though this behavior is the reason why Doombirds are famous, they don't do it often due to the risk it can provide. Instead, they normally hunt for smaller and weaker animals to eat, and lure their preys into death only in situations of emergency, such as a pregnancy. Female Doombirds bear their young for 3 months before giving birth to them; during the pregnancy, they get really fragile and vulnerable, and so, are brought to a hiding spot (normally a high one, such as the top of a tree), while the male hunts and brings food for her. Because of the luring trick they possess, after birth, the females take their babies for a trip over the sky so they can memorize the landscape and the behavior of the other animals.

A study has shown that young Doombirds that grow up by themselves, without their parents, rarely develop the luring trick. Therefore, it can be assumed that it is not a natural instinct of the species, and instead, a tactic they created a long time ago to obtain more food and have been teaching their descendants since. In fact, after this theory was formulated, some scientists and Beast Hunters decided to adopt newborn orphan Doombirds and take care of them, giving them all the food and water they needed. As they grew, they never once showed any kind of aggressive behavior towards any other animal, being extremely docile especially to their owners, proving the theory.

However, forcibly taking a Doombird who spent the majority or all of its life on the wilderness, for whatever reason, will make them react really badly. Feral Doombirds act extremely aggressive, not hesitating to attack any living creature who get near it or touches it, which is the reason that most people who do this keep them in cages and wear safety equipment. Most of the times, due to the stress of being taken from their lifelong home, those Doombirds can become heavily depressed, refusing to eat, drink or do anything, and may even die of that: specialists refer to that as Hiraeth. Occasionally, they can go into a frenzy, attacking any and everything in front of them, whether it is their cage, their own body or another creature; those periods of hysteria are dangerous because once it starts attacking someone else or themselves, they will not stop until it is dead or the Doombird is stopped by external force. Those frenzies can be short (lasting a few seconds or some minutes), long (during hours or even days), or permanent (where the Doombird ends up insane).