The bill defines the bird. It is wide, flattened, and fringed with fine combs that strain krill from seawater. The broad-billed prion does not chase its food. It sieves it. Flying low with head submerged, it filters the ocean like a tiny whale. That is not what most people expect from a bird. It works anyway. At sea, the bird is small and grey. A dark M marking crosses the upperwings. The tail tip is black. Flight involves rapid, twinkling wingbeats low to the water, twisting through swells. From a distance, a flock looks like grey moths fleeing the tide. Close up, the bill gives it away. Nothing else in the Southern Ocean has a bill quite like this. The structure is unique. The function is precise. Feeding relies almost exclusively on crustaceans, particularly krill and copepods. The lamellae inside the bill are fine enough to strain particles as small as a millimetre. The prion flies into a patch of krill, dips its head, and paddles forward. Water flows through the bill. Krill stays behind. Swallow. Repeat. This method requires calm seas and dense prey patches. It is efficient when conditions allow. Breeding colonies are enormous. Millions of birds occupy some islands. The noise at night is overwhelming. A constant chattering, purring, whistling sound rolls across the slopes like a wave. Each bird has its own burrow, dug into deep soil among tussocks or under ferns. The burrows are dark, damp, and surprisingly cosy. They provide shelter from the wind and predators. A single white egg arrives. Both parents incubate in shifts of two to three days. The chick hatches covered in grey down. Growth is slow. It is fed on regurgitated krill oil. That oil is energy dense. It keeps the chick alive while both parents forage hundreds of kilometres away. The investment is high. The return is a single fledgling. The broad-billed prion is the largest of the prions, but that is not saying much. It still fits in the palm of your hand. Light as air. Built for a life spent almost entirely on the wing. It lands only to breed and to rest on the water. Everything else happens in the air. The bird is a creature of the open ocean, tied to land only by the necessity of reproduction. In New Zealand waters, it is common but seldom seen from land. The subantarctic islands are its stronghold. The Antipodes. The Aucklands. Campbell. The Snares. On these islands, it is everywhere. Walking through a prion colony at night means stepping carefully. The burrows are everywhere. The birds do not move. They trust the darkness. They trust the soil. And mostly, they are right.