The Chatham Island shag was discovered by H.H. Travers during his visit to the Chathams in 1871. According to Oliver, in the first edition of his Birds of New Zealand, Buller described and figured it under the name of Phalocrocorax carunculatus and it was not until 1893 when Forbes published a paper on the birds of Chatham Islands that it was described as a distinct species and named after the Earl of Onslow, one of the Governors of New Zealand, who did much towards the protection of bird and plant life.
The Chatham Island shag is endemic to the Chatham Islands where "it is constantly seen at sea, usually within a few miles of the shore, settled on the water and diving for food or flying with a laboured wing beat". It is similar in size to the Stewart Island shag, and has a population of 500–1,000 breeding pairs.
Fleming describes the operations of red-billed gulls which form small colonies within the large breeding colonies of shags. He says that, "in addition to eating broken eggs, the gulls will consume the stomach contents of old and young birds, and have even been observed worrying nestlings until they disgorge".
According to Fleming, "breeding colonies may be either on outlying stacks, a few feet above the level of the wave wash, or on ledges on outstanding headlands fifty feet or more up a cliff. The nests are regularly arranged chimney pot structures of grass seawweed and feathers, firmly cemented with droppings". Pale blue eggs are laid from August to December.
The birds feed mainly in deep offshore waters, taking fish, octopus, squid and cuttlefish.
Members of the shag family belong to three groups, based on the colour of their feet: black, yellow or pink. Outside New Zealand, the black-footed shags are better known as cormorants. Pink-footed shags belong to the Leucocarbo genus. They are part of a group of cold-water shags found on islands in the Southern Ocean, on the Antarctic Peninsula and the south coasts of Australia and South America. They are also called blue-eyed shags as they all have a blue, purple or red ring around the eye - not a blue iris. This group are also all pink-footed. They all feed at sea. The six New Zealand species are found nowhere else. They nest on rock rather than in trees, which are absent in many of their habitats.
Other common names: —
63cm, 2.25kg, like King shag, orange caruncles, pink feet.
Where to find: —
Coastal and offshore islands of the Chathams.
More Information: —
Illustration description: —
Buller, Walter Lawry, A History of the Birds of New Zealand, 1888.
Oliver, W.R.B., New Zealand Birds, 1955.
Heather, B., & Robertson, H., Field Guide to the Birds of New Zealand, 2000.
Fleming, C., Emu, 38, 409, 1939.
Page date & version: —
Wednesday, 4 June 2014; ver2009v1