These are found throughout Australia except in Tasmania and the driest parts of the interior and are more common in the south and along the coast of south-western Australia, they are also found in New Zealand.
Though usually found in marine habitats such as estuaries, harbours and bays they are also attracted to inland waters, including lakes, rivers, mangroves and deep, open swamps. They are generally seen alone or in pairs but when food is abundant they sometimes congregate in vast flocks of hundreds or thousands.
They mainly feed on fish but will also take crustaceans and mollusks, like other cormorants they catch prey underwater by diving and swimming using their large, fully webbed feet for propulsion. As their feathers are not waterproof cormorants are regularly seen perched with their wings outstretched to dry after fishing.
They breed in colonies on coastal islands, flooded tree plains, mangroves or sometimes on artificial structures such as beacons. The large nest is constructed from seaweed, twigs or sticks cemented together with droppings and placed in a tree or on the ground. Both parents build the nest, incubate the eggs and feed the young.