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.

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.

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.

[10] 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.

[5] The first attempts to protect the area began in 1924, when an honorary ranger was appointed to monitor a 60-metre-wide (200 ft) strip on each bank of the Waitangiroto River.

[5] In the breeding season herons feed in the river and nearby Ōkārito Lagoon, and when these are too flooded to easily forage in adults can abandon their nests.

[5] The Wildlife Act 1953 made hunting of white herons illegal, and adult birds have no natural predators in New Zealand, though chicks are preyed on by stoats and Australasian harriers.

[24] Originally access to the colony was by jetboat down the Waitangitāhuna River to the lagoon, then up the mouth of the Waitangiroto to a boardwalk that led to the viewing station.

About 2500 tourists visit the colony each year during the breeding season—from mid-September when pairs are forming through to the end of fledging in February, after which birds disperse throughout New Zealand.

[23] Occasionally over autumn and winter the tourism company has offered tours of the rainforest or estuary for visitors interested in natural history.