The Little Black Cormorant is March's Bird of the Month.
Little Black Cormorant
The Little Black Cormorant is the smaller of the two species of predominantly black cormorants found in the Parklands. Its cousin, the Great Cormorant (Phalacrocorax carbo), is much larger, has a yellow facial patch and bill, and feathered “trousers” covering its thighs.
The Little Black Cormorant is black all over, with striking blue-green eyes, a slim grey bill with a hooked tip, black legs and black webbed feet. The back of the wings has a scalloped appearance, with a greenish sheen that becomes a bronze colour during breeding season. During breeding, fine white feathers also appear above the eyes and on the side of the neck. Immature birds have brown eyes and more brown in their plumage.
The Little Black Cormorant is usually found in freshwater habitats from inland dams to wetlands, lakes and rivers, and will also use sheltered coastal estuaries and lagoons. Their coastal population tends to increase during periods of inland drought. Their range extends throughout Australia, across eastern Indonesia, Papua New Guinea and down into the western Pacific islands and New Zealand where it is known as the Little Black Shag.
Like all Cormorants, the Little Black Cormorant hunts its prey by diving underwater and swimming with speed and agility in pursuit of its prey. By lacking waterproofing oils in their feathers, they reduce their buoyancy to enable diving. As a result, they must regularly leave the water and perch with their wings spread out to dry.
Their diet consists mainly of fish with some aquatic invertebrates and crustaceans. The introduced Carp is a major part of their diet in the Parklands and provides an abundant food resource.
Little Black Cormorants are often seen fishing in coordinated packs. They swim along the surface in a group, often near the edge of a pond or island, herding small fish into a position where the entire group can dive in and catch them to eat on the surface. Sometimes, a few members of the group will fly forwards to splash down and drive herded fish back toward the pack.
Little Black Cormorants only breed once in a season and in the Parklands, this can be any time from spring to autumn. A pair will work together to construct a platform of sticks in a fork of a tree, usually over water and near to other nesting Cormorants, Darters or Ibis.
The nest is lined with twigs, leaves and water weeds. Usually, around four eggs are laid, with up to seven eggs possible. The nesting pair share the incubation for three to four weeks and feed the chicks in the nest. The juvenile Cormorants remain at the nest for more than a month until they appear of similar size to the adults. Accumulated droppings collect in the nest and leach out in rain, resulting in complex ecological impacts from the nutrient and microbial load.
In the Park:
Little Black Cormorants can be found in all the ponds of the parklands. They may be seen individually, swimming, or perched by the pond edges, wings spread to dry, or swimming in hunting packs and roosting in groups of half a dozen or more in trees on the islands.
They share their roosting sites with the other Cormorant species in the park which provides an opportunity to compare the unique features of the different species.
Photo Credit: Tony Spira