Switching stitchbirds

Getting up before dawn, weathering rough seas, working during weekends and holidays and being scratched and pecked are not activities that today’s teenagers normally relish. But a team of students from Glenfield College in Auckland’s North Shore City accepted such conditions when they volunteered to help transfer endan­gered stitchbirds from Little Barrier Island to Tiritiri Matangi Island in the Hauraki Gulf in September 1995. The transfer was the latest in a series of Depart­ment of Conservation tactics aimed at helping the plight of the stitchbird or hihi, New Zealand’s rarest honeyeater.

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Related to the better known tui and bellbird, the stitchbird’s name derives from one of its calls which resembles the sound stitch.

Males and females differ in colour. The male plumage is the more striking: a distinctive black head decorated with a tuft of white feathers behind the eye and bordered by a yellow collar. The olive-brown female is less arresting, and can easily be mistaken for a bellbird in the dappled light of the forest.

Up to late last century, the stitchbird was abundant in North Island forests, and was described by the naturalist Sir Walter Buller as “compara­tively common” in his first edition of A History of the Birds of New Zealand pub­lished in 1873. But in the second edition, published 15 years later, he wrote “The Hihi has become the rarest of our existing native birds.

The stitchbird had disap­peared from the mainland by 1885, unable to tolerate the rapid environmental changes associated with European settlement. An introduced avian disease is suspected of having had the most impact. A remnant isolated on Little Barrier Island became the sole surviving population, and remained so until transfers to other islands started in 1980.

The establishment of additional stitchbird populations has been at­tempted on Cuvier and Hen Islands (outer Hauraki Gulf), Kapiti Island (Wellington coast), and Mokoia Island (Lake Rotorua). The Hen and Cuvier populations have not been successful, and the Kapiti Island population is considered to be only just holding its own, at about 50 birds. It is too early to know how well the Mokoia Island population will fare, as the transfer took place only in 1994.

After identify­ing Tiritiri Matangi Island as being a potential stitchbird habitat, the Department of Conservation invited Glenfield College staff and students to participate in the transfer, based on the school’s involvement in restoration work on the island over the last 11 years. Twenty-six students took part.

The first step was to prepare a proposal that outlined reasons for the transfer. Students investigated issues of food availability, potential for competition with tui and bellbird already established on the island, and nesting requirements for the new popula­tion.

Once the proposal Z had DOC approval, one group of students o was trained in bird‑catching techniques,while another built 60 nest boxes. The stitchbird normally nests in cavities, a commodity that is in short supply in the young emerg­ing forest of Tiritiri. Provid­ing nest boxes was a way of ensuring that sufficient nesting sites were available on the island. It is also easier to gauge breeding success if the birds use known nesting sites.

The actual capture and transfer of the stitchbirds took place in the August school holidays. Two groups of students spent one week each on Little Barrier minding mist nets set on the lower slopes of the island. Mist nets are not selective, so the skill of disentangling many bird species from the nets was quickly learned, but not without fingers suffering from claws and beaks. The majority of captured birds were tui and bellbird, but whitehead, grey warbler, saddleback, kakariki and even kaka also found their way into the mesh.

Several hundred people travelled to Tiritiri Matangi for the transfer. Thirty-seven stitchbirds-18 male, 19 female—were transported from Little Barrier by helicopter. Following an informal powhiri to welcome the birds to their new home, students helped Tiritiri conservation officer Ray Walter release the birds at three sites (below), with visitors eager to glimpse what was, for most, their first view of this attractive native bird.

Reports since the release indicate that visitors stand a reasonable chance of seeing a stitchbird, thus adding to the list of indigenous species that attract 20,000 visitors annually to Tiritiri Matangi.

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