There are some 36 species of shag worldwide. Twelve of these are found in New Zealand, of which eight are endemic (found nowhere else). In many countries, shags are called cormorants. The name shag is thought to refer to the shaggy crest some species have on their heads. Four species of shag are found at ZEALANDIA: the kawau pū (black shag), kāruhiruhi (pied shag), kawau tūī (little black shag) and kawau paka (little shag). These four species all belong to the genus Phalacrocorax, the black footed shags, which are found mainly in freshwater or coastal seawater.
Shags are swift underwater swimmers, with a sharp hooked beak to help them catch fish and small crustaceans. They are often seen sitting on a perch with their wings spread out, drying their feathers. This is because a shag’s feathers are not waterproof, making it easier for them to dive and stay underwater for an average of 20 to 30 seconds per dive. But it also means the birds quickly get waterlogged and cold. So after a bout of fishing, shags must spend a lot of time preening and drying to restore their feathers and warm up.
Adult kāruhiruhi are very striking pied birds, almost equally divided between black and vivid white. The white is on the underside from just below the bill, all the way down their long neck and belly to the underside of the tail. From above the beak and all the way down the back they are a dark blackish brown. The edges of their feathers are darker, giving the birds a fine scalloped look. The eye is bright blue and there is a patch of bright yellow skin just in front of the eye (this colour is brighter in the breeding season). The grey beak is long, with a sharp hook at the end.
Juveniles are a lighter brown on the back and the white parts are mottled with pale brown. They lack the blue eye and yellow face patch of the adults. The large nest is constructed from seaweed, twigs or sticks cemented together with droppings, and is in a tree or on a cliff face. Both parents build the nest, incubate the eggs and feed the young. Adults tend to stay in their territory year-round, with juveniles dispersing widely.
This species is in decline in parts of New Zealand but making a return to Wellington. The pied shags found their own way to ZEALANDIA - with the first 1 or 2 appearing in 2005, the first successful nesting in 2010, and now over 90 birds and 20 nests found at the sanctuary.