wedge tailed shearwater

The wedge-tailed shearwater (Ardenna pacifica) is a prominent member of the Procellariidae family. Often called a muttonbird, this medium-large seabird is a master of the tropical Pacific and Indian Oceans. Known for its graceful flight and wide distribution, it remains a fascinating subject for ornithologists and birdwatchers alike.

Measuring between 41-46 cm, the wedge-tailed shearwater is the largest of the tropical shearwaters. It features a distinct wedge-shaped tail and exists in two color morphs: dark (sooty brown all over) and pale (grey-brown above, white below). Its bill is dark, and its salmon-pink legs are positioned far back on the body, a specialized adaptation for swimming.

This species is partly pelagic, spending most of its life in offshore waters across the tropical Pacific and Indian Oceans. They are frequently spotted following fishing boats. Their breeding range includes islands off Japan, Hawaii, the Seychelles, and Australia, typically between latitudes 35°N and 35°S.

The diet of the wedge-tailed shearwater is primarily composed of 66% fish, with goatfish being the most common prey. They also consume squid and crustaceans. They typically feed pelagically by dipping to the surface or plunging their heads underwater while on the wing.

Wedge-tailed shearwaters breed in colonies on oceanic islands. They are known to nest in burrows or under rock crevices to protect their offspring. These birds are highly colonial, often returning to the same nesting sites annually to raise a single chick during the breeding season.

These birds are expert gliders, utilizing their large tails for stability in flight. Their feeding behavior includes dipping to the water surface and shallow plunging, though they seldom submerge their entire bodies. They are often seen in multi-species feeding flocks over schools of predatory fish like tuna.

While the wedge-tailed shearwater has a large range and significant population, they face threats from invasive species (like rats and cats) on breeding islands and plastic pollution in the oceans. Currently, they are generally classified as a species of Least Concern, though local populations require monitoring.

1. It is one of several species colloquially known as a muttonbird.
2. The pale morph is more common in the North Pacific, while the dark morph dominates elsewhere.
3. Their legs are set so far back that they are quite clumsy on land but excellent swimmers.
4. They belong to the Thyellodroma group, a superspecies of large shearwaters.

• Look for them in offshore waters near tropical islands.
• Scan the area around fishing vessels, as they often follow boats for easy meals.
• Use high-quality binoculars to distinguish between the dark and pale morphs.
• Watch for their characteristic gliding flight and the silhouette of their wedge-shaped tail.

The wedge-tailed shearwater is a resilient and wide-ranging seabird that plays a vital role in the marine ecosystem. Whether you are observing them from a boat or a coastal lookout, their elegant flight and unique physical adaptations make them a highlight of any birdwatching excursion.