A sleek, dark seabird built like a fighter jet with anger management issues. The Arctic skua spends the northern summer terrorising seabird colonies across the Arctic tundra. Then it flies south to do the same thing all over again in the Southern Ocean. Some birds migrate for warmth. This one migrates for the pleasure of being a consistent nuisance. The motivation is clear. It enjoys the chase. On the wing, it looks like a pumped-up tern with a bad reputation. Two central tail feathers extend past the rest. They trail like aerial whiskers. This is useful for identification. It is also useful for looking slightly unhinged. That suits the bird perfectly. The appearance matches the behaviour. The behaviour is aggressive. The appearance supports it. It hunts small birds, rodents, and insects on its breeding grounds when it has to. But that is honest work. The Arctic skua prefers a less honourable trade. It chases other seabirds. Terns, kittiwakes, and puffins are targets. It forces them to drop or disgorge their catch. The victim flees, twisting and screaming. The skua follows. It is silent. It is close. It waits for a mistake. When the food falls, the skua catches it midair. No thanks are offered. No apology is given. The transaction is one-sided. This is called kleptoparasitism. It is a fancy word for piracy. The skua is very good at it. The technique is refined. The success rate is high. It relies on the weakness of others. It exploits their fear. It does not hunt. It steals. Breeding takes it to open Arctic tundra. It scrapes a shallow depression in the moss. It lays two spotted eggs. Both parents defend the territory with dives and vocal threats. A skua that has decided you are too close will not negotiate. It will simply escalate. The defence is immediate. It is intense. It discourages intrusion. Outside the breeding season, it lives entirely at sea. It follows storms and frontal systems where food concentrates. It does not land for months at a time. It sleeps on the water. It eats on the wing. It is a life stripped down to movement and theft. There is no rest. There is only the next opportunity. The dark and pale colour morphs appear across the population. These are two distinct plumage forms. Possibly camouflage. Possibly evolution having a fun afternoon. The variation exists. The reason is unclear. It does not matter for survival. Both forms succeed. In New Zealand waters, Arctic skuas are regular summer visitors. They arrive in October. They leave in April. Most are seen from headlands and beaches. They chase other seabirds. They scream. The presence is seasonal. It is predictable. The call is a harsh, chattering "kee-kee-kee". It is often given in flight. It sounds like a warning. It is one. The bird announces its intent. It does not hide it. It carries on.