Pied Cormorant

Learn About the Australian Pied Cormorant, a Striking Black and White Waterbird

The Australian pied cormorant, also referred to as the pied cormorant, pied shag, or great pied cormorant, is a medium-sized bird that graces the shores of Australasia. In New Zealand, it is commonly called the pied shag or by its Māori name, kāruhiruhi. Historically, it was sometimes labelled as the “yellow-faced cormorant.”

Description and Taxonomy

This species was first described in 1789 by the German naturalist Johann Friedrich Gmelin in an updated edition of Carl Linnaeus’s Systema Naturae. Gmelin initially placed it in the genus Pelecanus and named it Pelecanus varius. His description was drawn from the “pied shag” observed in Queen Charlotte Sound, New Zealand, earlier described by English ornithologist John Latham in 1785.

The pied cormorant is now one of twelve species in the genus Phalacrocorax, introduced by the French zoologist Mathurin Jacques Brisson in 1760.

The two subspecies exhibit slight physical differences. It can be confused with the black-faced cormorant (slightly smaller) and the little pied cormorant (significantly smaller).

• P. v. hypoleucos: Found in coastal and inland Australia (excluding the central-south) and Tasmania.
• P. v. varius: Located in coastal areas of North, South, and Stewart Island in New Zealand.

Physical Characteristics

The pied cormorant is predominantly black on its back and the upper surface of its wings, while its underside is white. Males weigh around 2.2 kg, whereas females typically weigh about 1.7 kg. The bird stands between 65–85 cm tall and boasts a wingspan of 110–130 cm.

A distinctive yellow patch between the bill and the eye on each side of the head led to its historical common name. It possesses large webbed feet used for underwater navigation, steering with partially opened wings.

The bird’s large hooked bill, green eyes with a blue eye ring, and black legs and feet are notable features. Its eyes are protected underwater by a special nictitating membrane.

Often seen spreading its wings post-dive, the cormorant dries its feathers due to insufficient waterproofing, which may aid in reducing buoyancy underwater.

Distribution and Habitat

In Australia, it is moderately common in the eastern states and abundant in the south-west, particularly along the coast. It is present in every state except Tasmania.

The pied cormorant frequents marine habitats, sometimes alone, in pairs, or in large flocks. They are also drawn to inland waters, including lakes, wetlands, and rivers. In Australia, they are often seen at inland waterways, while in New Zealand, they prefer coastal areas near prey. The birds are generally sedentary, roosting in trees, on rocks, or logs in the water, and are unaffected by varying salinity, turbidity, and shoreline vegetation as long as there are available perches.

Behaviour and Ecology

Feeding

Pied cormorants primarily feed on benthic fish ranging from 6–15 cm in length, mostly from waters less than 10 metres deep. They are known to consume Whiting juveniles and other crustaceans like prawns and shrimp, along with some molluscs and cephalopods. They dive in both shallow, calm waters and fast-moving currents, typically staying submerged for about 40 seconds with a recovery period of 10–15 seconds between dives.

They feed in both deep and shallow waters, with flock densities reflecting prey abundance.

Hunting is often solitary to avoid stealing, though larger groups may gather when small fish schools are near the surface.

Predation risk from sharks and food abundance present a trade-off, with cormorants sometimes opting for deeper waters with less abundant prey to avoid sharks during warmer months. Deeper waters necessitate longer dives and corresponding rest periods on the surface.

Breeding

Pied cormorants prefer breeding in small, sheltered colonies near harbours, estuaries, and lakes, with rare occurrences on exposed coasts or islands.

Courtship begins with the male near a prospective nest site, involving silent wing waving and gargling for female recognition. Males may also hop up to a metre in the air to attract females.

Nests are large platforms of sticks and foliage cemented with droppings, typically 80 cm in diameter, built on the ground or in trees. Males gather most nesting materials, while both sexes share construction duties.

Nests are reused biannually by different breeding pairs, with some breeding occurring in summer and winter by younger pairs.

Monogamous pairs from the age of two, lay eggs once a year with a breeding cycle averaging six months. Clutch sizes range from 2–5, with an incubation period of 25–33 days.

Both parents share egg and fledgling care duties, with chick rearing taking 47–60 days and independence achieved just over three months of age. Feeding duties are shared through incomplete regurgitation.

Studies suggest that pied cormorants do not stray far from their colonies, typically staying within 20 kilometres. They generally fly at low altitudes, as they possess weaker flight capabilities than other species in their family, often forming ‘v’ formations when in flocks.

Conservation Status

The bird faces a high-moderate risk from fishing activities, notably from set and inshore drift nets. Birds in colonies are often found entangled in fishing lines with hooks embedded in their bodies. Historically, they were sometimes shot due to perceived competition with commercial fishing.

Its conservation status is ‘secure’ federally, shifting to ‘near threatened’ in Victoria. It is classified as “Least Concern” according to the IUCN 3.1 standards, indicating a stable population across a large range.