About Phalacrocorax varius (Gmelin, 1789)
The pied cormorant, with the scientific name Phalacrocorax varius (Gmelin, 1789), has distinct two-toned plumage: its back and the upper surfaces of its wings are predominantly black, while its underside is white. Males weigh approximately 2.2 kg, and females weigh around 1.7 kg. The species stands between 65 and 85 cm tall, with a wingspan ranging from 110 to 130 cm. A small yellow patch located between the bill and eye on each side of the head is thought to be the origin of its historical common name. It has large webbed feet that it uses to chase fish underwater, and steers with partially opened wings. The bird has a large hooked bill, green eyes surrounded by a blue eye ring, and black legs and feet. A special nictitating membrane protects its eyes when it is underwater. Because its feathers do not have adequate waterproofing, pied cormorants are often seen spreading their wings after diving to dry their feathers. This reduced waterproofing may help the birds stay underwater longer, as it lowers their buoyancy. The two recognized subspecies have slight physical differences from one another. Species similar to the pied cormorant include the slightly smaller black-faced cormorant and the substantially smaller little pied cormorant. The IUCN Red List of Threatened Species classifies the pied cormorant as Least Concern, due to its large range and relatively stable population. In New Zealand, the species is listed as Nationally Vulnerable. On New Zealand's east coast, its current range extends as far south as Christchurch; this is a recent range expansion, as older sources note the species did not occur further south than Kaikōura. This range expansion followed population recovery after heavy persecution of the species in the early 1900s, and most likely represents recolonization of the species' former range. The New Zealand pied cormorant population has grown from around 700 breeding pairs in the 1950s to an estimated 3,000 breeding pairs after 2000. In Australia, the pied cormorant is only moderately common in eastern states, occurring both on the coast and in inland wetlands, but is abundant in south-western Australia, particularly along the coast. It is found in all Australian states except Tasmania. Its federal conservation status in Australia is 'secure', and it is only classified as 'near threatened' in the state of Victoria. The pied cormorant faces a high to moderate risk from fishing activities, especially from set nets and inshore drift nets. Birds in colonies are frequently found entangled in recreational fishing line, with hooks embedded in their bodies. In the past, pied cormorants were viewed as competition for commercial fishing and were sometimes shot. Although the species is typically found in marine habitats, where it may occur alone, in pairs, or in very large flocks of hundreds or thousands of individuals, it is also attracted to inland waters including lakes, deep and open wetlands, and rivers. In Australia, pied cormorants are often found at inland waterways, while in New Zealand they prefer coastal areas close to their prey. Adult pied cormorants are sedentary, and often roost in trees, on rocks, or on logs in the water. The species is not affected by variable salinity, water turbidity, or shoreline vegetation, as long as suitable perches are available.
