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 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.
The king shag (Leucocarbo carunculatus) is known to Māori as kawau pateketeke. When the Resolution anchored in the Marlborough Sounds on James Cook’s second voyage in 1772, the German naturalist Johann Reinhold Forster and his son Georg took a specimen of this striking black-and-white bird.
Breeding in colonies, they spend months building twiggy nests on rock, and lay one to three eggs in May or June. They tend to feed in sea water that is 20–40 metres deep, taking flounder, sand eels, cod and other fish as well as crayfish and crabs from the sea floor. Their dives last from 45 to 90 seconds.
A count in 2001 found there were just 650 king shags. Considered to be among the world’s rarest seabirds, the king shag has been rated ‘vulnerable’ by the World Conservation Union. It was once widespread (fossil bones dating between 2,000 and 3,000 years old have been found in Northland and elsewhere), but is now found only on islands around the Marlborough Sounds; most likely their numbers were reduced by Māori through hunting. Nelson Māori used to lower men over cliffs by ropes to capture the big birds on their roosting sites.
More than most shags, the king shag is very easily frightened. It is scared off by people landing on the islands where it breeds, and is disturbed by boats that approach closer than 100 metres.
Stewart Island shags
Closely related to the king shag is the Stewart Island shag (Leucocarbo chalconotus), which breeds from North Otago down to Stewart Island. Breeding and roosting in flocks on steep cliffs and rugged offshore islets, this shag has two distinct colour morphs or forms – one wholly black with a greenish gloss (in this form the bird is sometimes named the bronze shag), and the other black and white. Research suggesting that the Stewart Island shag is actually two species (Leucocarbo stewarti and Leucocarbo chalconotus) was in 2016 being considered by the Birds New Zealand Checklist Committee.
The Stewart Island shag is considered rare, with the population estimated at 1,600–1,800 breeding pairs. Twiggy nests are built in cliffs, and one to three pale blue eggs are laid from September to November. The shags feed on bullies, as well as other fish, crabs, shrimps and octopus taken from the sea floor in water less than 30 metres deep.
Other pink-footed shags
Mere specks in a vast ocean, New Zealand’s southern offshore islands are home to four species of pink-footed shags, whose ancestors probably colonised the islands by chance. As they were not well adapted for long-distance flight, they remained separated and evolved into distinct species. All four are classified as rare, and are not found outside each group of islands.
Chatham Island shags
The Chatham Island shag (Leucocarbo onslowi) is endemic to the Chatham Islands. It has a population of only 355 breeding pairs. Pale blue eggs are laid from August to December in nests perched on high rocky sites. The birds feed mainly in deep offshore waters, taking fish (flounder, bullies), octopus, squid and cuttlefish.
Bounty Island shags
The Bounty Islands are a small, isolated group of bare granite rocks in the Southern Ocean, 820 kilometres east of Stewart Island. The Bounty Island shag is found only on these islands, which it shares with thousands of other seabirds and many seals. A survey in 2011 found about 620 shags. They build nests on rock using seaweed they collect by diving to depths of 10 metres. Two or three pale blue eggs are laid in October–November. Food includes fish, squid, isopods (slater-like crustaceans) and sea urchins.
Talking of shags
In Māori sayings, someone obviously poised to leave is compared to a shag (kawau) ready for flight: ‘Ka mārō te kakī o te kawau’ (the shag’s neck is stretched out). People on a determined course of action are ‘me kawau ka tuku ki roto i te aro maunga’ (like a shag making for a mountain face). Shags also symbolise tenacity: ‘E kore te kawau e neke i tona tumu tu’ (the shag will not move from his stump).The dejected air of a sitting shag gave rise to the Kiwi phrase, ‘as miserable as a shag on a rock’.
Auckland Island shags
The Auckland Island shag (Leucocarbo colensoi) breeds on the subantarctic Auckland Islands. The population was estimated at 4,500 birds in 2011. Nests are mostly built on ledges or tall basalt columns along the cliffs, preferably under an overhang for protection from skuas. Three pale blue eggs are laid between November and February, and incubation is around 28 days. Their diet is fish and marine invertebrates.
Campbell Island shags
Campbell Island, 700 kilometres south of New Zealand, is the home of the Campbell Island shag (Leucocarbo campbelli). There are about 2,000 breeding pairs on the island. Two pale blue eggs are laid between November and February. One bird on this island was recorded living at least 13 years. The birds feed in large flocks, fanning out in a line before diving. They forage in harbours as well as far out to sea, and feed on fish and marine invertebrates.