Cormorano dalla faccia nera

Identificazione

Like other cormorant species, the black-faced cormorant is a large aquatic bird, with a long hooked bill, webbed feet, and monochromatic plumage. This is one of the largest cormorants found in south-western Australia and has pied plumage with the upper half of its body black and the undersides white. Its face is naked and black, hence the "black-faced" name, and the tail, feet, and thighs are also black. The back feathers are glossy, and its bill is dark grey with a prominent hook at the tip. It has blue-green eyes. When flying, it holds its head level or lower than its body and holds its wings in a cross-shape like most cormorants.<p>Species that are similar in appearance include the pied cormorant (slightly larger) and the little pied cormorant (slightly smaller).<p>The breeding and non-breeding plumages are very similar, with the formation of fine white streaks along the neck during breeding until eggs are laid. Juveniles have dark-brown upper feathers, including dark ear coverts and a dark face, with a lighter underside streaked with brown. Following the Juvenile plumage, black-faced cormorants have immature plumage which are similar to adult plumage.<p>Black-faced cormorants have very subtle sexual dimorphism, making it difficult to differentiate sexes in the field. In general, males are larger and more robust than females, who are more slender in comparison. Males also have larger bills than females, with male bills measuring greater than 77 millimeters and female bills less than 76 mm.<p>Black-faced cormorants are usually silent when away from the breeding colony. However, when they are at their nests, the male will emit a loud honk or guttural croak, and the female will hiss when approached.

Tassonomia

The black-faced cormorant is one of around 40 species in the cormorant and shag family Phalacrocoracidae. This family split off from the darter family Anhingadae over 40 million years ago, so it has a relatively independent evolutionary history. Of the suggested 7 genera in the cormorant family, the black-faced cormorant is part of the Old-Word cormorants Phalacrocorax. This genus diverged from its sister genus, the North-Pacific Cormorants Urile around 10 million years ago.<p>The closest related species to the black-faced cormorant is the pied cormorant P. varius.

Nome scientifico

Phalacrocorax fuscescens

Autorità

(Vieillot, 1817)

Ordine

Suliformi

Famiglia

Phalacrocoracidae

Genere

Phalacrocorax

Areale e habitat

Black-faced cormorants are endemic to the coastal regions of southern Australia and Tasmania. The population is estimated to in the tens of thousands, and is distributed across Western Australia, South Australia, Victoria and Tasmania, particularly in the Bass Strait and Spencer Gulf. There are two independent populations: one on the southern coast of Western Australia, and the other on the coasts of Southern Australia, Victoria and Tasmania.<p>Unlike the other cormorants found around the Australian continent, the habitat of the black-faced cormorant is exclusively coastal and marine. They can be found in coastal waters, inlets, rocky shores, and offshore islands. Occasionally black-faced cormorants can be found in estuaries of rivers. Colonies are usually found on steep cliffs and rocky islands where they nest. In the winter, black-faced cormorants leave coastal waters to breed in these colonies.

Migrazione

Resident species

Conservazione

Tendenza della popolazione

unknown