The Waitangiroto Nature Reserve is a protected area of near Whataroa, in the West Coast of New Zealand. The reserve consists of lowland kahikatea swamp forest either side of the Waitangiroto River. It is notable as the site of the only breeding colony of kōtuku or white heron (Ardea alba modesta) in New Zealand, comprising 100–120 birds. Royal spoonbills and little shags also breed alongside the kōtuku. The breeding colony is a visitor attraction during the breeding season, but access to the entire nature reserve is by permit only. Visitors can view the birds from a hide across the Waitangiroto River. Tours of the reserve operate from a base in Whataroa.
Although the kōtuku nesting colony is commonly known as the "Ōkārito colony", Ōkārito is some distance to the south, over a glacial moraine in a different drainage basin. White herons can be commonly seen feeding in Ōkārito Lagoon, a possible cause of the confusion.
History
The kōtuku colony was known to local Māori, and in 1860 they unsuccessfully petitioned the authorities to create a native reserve which included it.
On 30 December 1865 surveyor Gerhard Mueller took a waka and paddled up the "Waitangi-Roto" River, in search of a lake he was told was fifteen or twenty miles inland. A few miles up the river, he came across the "cranery", and described the white herons there in a letter to his wife Bannie:Of these birds (near 4 ft. high) imagine seeing around you from 50 to 60, sitting on high pines and lower trees, in a circle of about 150 yards, their pure white feathers shining in the sun. It was a glorious sight—I gave up pulling, and watched the tribe for a long time. They were not at all shy—kept up a continual 'plappering' amongst themselves, and seemed to be astonished at me more than afraid... I am glad now I had no gun with me—it would have been a pity to disturb this peaceful community.This was the first sighting of the kōtuku colony by Europeans. Six years after Mueller's account Thomas Potts visited and counted 25 nests. In 1876 Augustus Hamilton found only six nests remaining, and because "certain miscreants destroyed a quantity of nearly-hatched eggs", tearing down saplings to procure them, the birds had abandoned the colony; Hamilton hoped the birds would "find a more secure place for their new home".
Biology
The reserve includes kahikatea forest, bog, lake, lagoon, and other coastal habitats. Mueller remarked on the dense bush either side of the river, with "beautiful Kowhai trees abounding and almost all shrubs in flower…". At the colony, kōtuku and little shags / kawaupaka (Microcarbo melanoleucos) nest in the crowns of tree ferns (Dicksonia squarrosa), kōwhai (Sophora microphylla), kāmahi (Pterophylla racemosa), and māhoe (Melicytus ramiflorus). Royal spoonbills / kōtuku ngutupapa (Platalea regia) nest higher up in emergent kahikatea (Dacrycarpus dacrydioides) trees. The Waitangiroto River which flows through the reserve is slow, peat-stained, and swamp-fringed, typical of coastal West Coast waterways.
The Waitangiroto Nature Reserve is the only known nesting area for kōtuku or white herons (Ardea alba modesta) in New Zealand. White herons, also known as Eastern great egrets, are common in Australia and South-East Asia but reach their south-eastern limits in New Zealand. The Waitangiroto colony was likely founded by Australian birds blown across the Tasman; it has persisted because Ardea alba is faithful to its place of birth (natal site fidelity) and will return to the same nesting site each year. Outside of the breeding season, the adult birds disperse throughout New Zealand and are solitary.
Conservation
The first attempts to protect the area began in 1924, when an honorary ranger was appointed to monitor a strip on each bank of the Waitangiroto River. By 1940, there were only four nests at the colony. A paid ranger was appointed to monitor and protect the colony and escort visitors in 1944. The area was gazetted as a Waitangiroto Wildlife Refuge in 1957 after an adjacent Māori nature reserve had been acquired. The reserve was reclassified into the Waitangiroto Nature Reserve in 1976, and access to the colony was restricted to by permit only.