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Story: Merton, Donald Vincent

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Merton, Donald Vincent

1939–2011

Threatened bird expert, wildlife officer, conservationist

This biography, written by Alison Ballance, was first published in the Dictionary of New Zealand Biography in 2022.

Don Merton’s pioneering conservation efforts brought three threatened New Zealand bird species back from the brink of extinction and inspired similar conservation programmes around the world. From the early 1960s ‘the man who saved the black robin’ revolutionised the intensive management of endangered birds such as kākāpō and Chatham Island black robins, including by cross-fostering robin chicks to other species to boost the numbers from the single remaining breeding pair. He developed world-leading techniques for the translocation of species, including the last-minute rescue of tīeke (South Island saddlebacks) and the relocation of every known kākāpō to safer island homes. He recognised the threat that introduced mammalian predators such as rats and stoats posed to island birds and championed the importance of predator control and island eradication efforts, both in New Zealand and on Indian Ocean islands.

‘Bird brain’

Donald Vincent Merton was born in Devonport, Auckland on 22 February 1939, the youngest of three boys born to Eileen Valerie Murray and her husband, Glaisher Vincent Merton (known to his family as Major). In 1940, the family moved to Wainui Beach, near Gisborne, and later Mangapapa, when Glaisher was appointed Automobile Association officer for the Gisborne-East Cape area. Following his early death in 1948, Eileen remarried, taking the surname Ellis, and had a fourth son.

Don Merton had a singular passion for birds from an early age. His parents and grandparents encouraged his interest, which earned him the nickname ‘bird brain’ at school. Efforts to find wild birds’ nests taught him observational skills and patience, and he learnt how to keep birds in captivity in his home aviary. Noticing the gradual disappearance of local weka introduced him to the idea of extinction. During a visit from his grandmother he found some goldfinch eggs and gave them to her canary to hatch and raise. He also got a bantam to hatch a harrier egg, and many years later recalled these early cross-fostering efforts and used them in the Chatham Island black robin conservation project.

Merton was befriended by local accountant Archie Blackburn, a keen birdwatcher and member of the Ornithological Society of New Zealand and the Royal Forest and Bird Protection Society, and active in acclimatisation society work. Blackburn encouraged his interest in birds, nurtured his growing appreciation of conservation, and told him about the Wildlife Branch of the Department of Internal Affairs, which was tasked with protecting native species as well as managing freshwater fisheries and game birds.

In 1957, at his second attempt, Merton was accepted as a trainee wildlife officer, beginning a 48-year career with birds and conservation in the Wildlife Service and its successor, the Department of Conservation (DOC). The Wildlife Service posted him around the country and on many remote islands during a three-year traineeship, working with species ranging from royal albatross to the recently rediscovered takahē. He often worked with senior wildlife officer Brian Bell, and the pair developed a lifetime friendship that was all the stronger for the pair’s very different personalities: Merton was shy and conflict-averse, while Bell was confident, articulate and happy to publicly support the younger man in his work.

The tīeke / saddleback story

In 1963, after a year’s sabbatical working with lyre-birds in Australia, Merton was appointed the first Auckland-based fauna protection officer for the Wildlife Service. Bell was his manager, and tasked the young conservationist with establishing a second population of tīeke (North Island saddlebacks), which at that time were confined to a single island, Taranga / Hen Island off the coast of Northland. Previous attempts to transfer tīeke to create a back-up population had failed.

As was the case with most New Zealand birds at that time, very little was known about even the most basic breeding biology and behaviour of the species. Merton assembled a team of volunteers to help him better understand the bird, prior to developing a translocation plan. They included Blackburn, young members of the King’s College Bird Club led by Dick Sibson, botanists Ian Atkinson and John Campbell, sound recordist John Kendrick and bird photographer Geoff Moon. These individuals would provide advice and support to Merton throughout his subsequent career, and the success of the endeavour made him an early champion of involving conservation volunteers in projects.

After four field trips to study the birds, Merton decided on a revolutionary method using fine mist-nets to catch the unwary birds as they flew in response to the playing of recorded territorial calls. The captured birds were temporarily held together in an aviary and fed a range of food that included stale fruitcake. Twenty-three North Island tīeke were successfully transferred to Whatupuke / Middle Chicken Island, via dinghy, in January 1964, and were breeding within a year. It was the first successful transfer of an endangered New Zealand bird for conservation purposes. Translocations such as this have since been used many times for a wide range of species globally.

On 2 April 1966, in Gisborne, Merton married Margaret Dawn Johnston, a Gisborne-born and raised nurse. Although Margaret – and, later, their son David – sometimes joined Merton on expeditions, his long absences on fieldwork would be a hallmark of the marriage.

Lessons from Big South Cape

Within a few weeks of the 1964 tīeke transfer, the Wildlife Service received news that there was a plague of rats on Taukihepa (Big South Cape Island), one of the Rakiura (Stewart Island) tītī islands. The island had outstanding prospects for bird breeding, and was home to four species found nowhere else: the greater short-tailed bat, Stead’s bush wren, South Island snipe and South Island tīeke. It took until August for the Navy to transport a team of wildlife experts, including Merton and Bell, to Taukihepa for a last-ditch rescue effort. The newly developed techniques worked well with South Island tīeke, but the few tiny bush wren that were caught proved difficult to feed as they required live insects, and the two snipe that the team managed to catch soon died. No attempt was made to rescue the greater short-tailed bat, as it had yet to be recognised as a different species. Some South Island tīeke were successfully translocated to Big Island and Kaimohu, but the bush wren translocation to Kaimohu did not succeed. Three species went extinct: bush wren, snipe and greater short-tailed bat.

The recognition that introduced rats can cause extinctions was a wake-up call for the New Zealand conservation community, especially Merton, who was determined that the Taukihepa tragedy would never be repeated. South Island tīeke have since been moved to many islands and to mainland predator-free sanctuaries, and rats were finally eradicated from Taukihepa in 2006.

Black robin and the legacy of Old Blue

In 1976, the Wildlife Service made a last-ditch effort to save the Chatham Island black robin, which – with just seven known birds – had the dubious distinction of being the rarest wild bird in the world. All seven were confined to a small area of bush on top of tiny Little Māngere Island, to the west of Pitt Island in the Chathams. Bell led a team, including Merton, that scaled the island’s cliffs in an effort to catch the remaining birds, which included just two females, and transfer them to nearby Māngere Island, where they would be easier to manage. Merton was overseas for the following years, and by the time he became involved with robins again in 1980 the population was down to just five birds. The next step, led by Merton, was to try intensive management; this included providing safe nesting boxes and attempting the cross-fostering of robin eggs and chicks to warblers. The idea was that the warblers would raise these chicks while the robins laid a further clutch, thus maximising the number of chicks produced in a season. The scheme was partially successful and there were eight robins by the end of the breeding season; however, while the warblers could successfully rear robin chicks for a few days they could not get them through to fledging.

In the breeding season of 1981–82, Merton and his team set about cross-fostering black robin eggs to tits, which were now only found on South East Island. This had the added difficulty of a boat trip between islands, but proved a more successful strategy, although there were issues with robin chicks thinking they were tits like their foster parents. The population stood at 12 birds by season’s end, with all chicks the progeny of a single pair, the female Old Blue, who had laid three clutches of eggs that year, and her mate Old Yellow.

Over the next few seasons, Don and the team steadily worked away at solving problems and refining techniques, and when intensive management stopped in 1989 there were over 100 black robins, all the progeny of Old Blue and Old Yellow. By the early twenty-first century the population was over 200 birds, living on Māngere and South East islands. The three Wild South documentaries about the black robin conservation programme ensured that Merton and Old Blue became household names.

Species on the brink – the giant flightless kākāpō

Until the 1970s, very little was known about New Zealand’s nocturnal parrot, the rare and mysterious kākāpō. One of Merton’s most significant early contributions to kākāpō recovery was recognising, based on experience with lyre-birds and grouse overseas, that the species is a lek breeder, in which the males compete for the attention of females through territorial displays and rituals. The distinctive track and bowl systems that male kākāpō excavate are display areas from which they make booming and chinging calls to attract females. The kākāpō is the only parrot, the only flightless bird and the only New Zealand bird with a lek breeding system. It breeds every two to four years following the irregular mass seeding and fruiting of trees such as rimu.

In the early 1970s Merton led teams into remote Fiordland valleys to locate the last known remaining kākāpō, which turned out to all be males, including one (named Richard Henry after a pioneering conservationist interested in kākāpō) who would become the only surviving Fiordland bird to contribute to the species’ recovery. The discovery of a breeding population of kākāpō on Rakiura (Stewart Island) in 1977 proved a turning point. In 1979 Merton’s meticulous research into faint feather markings allowed him to positively identify the first female kākāpō seen in over a century.

When feral cats began killing kākāpō on Stewart Island, a decision was made to move all known birds to safer islands, including Maud Island, Hauturu (Little Barrier Island) and Whenua Hou (Codfish Island). The population fell to a low of 51 known birds in the early 1990s, when an intensive recovery programme, led initially by Merton, was begun. It included supplementary feeding, hand rearing, using electronic technology for close monitoring of kākāpō activities and nest manipulation, and moving eggs and chicks between nests to maximise chick survival. By the time of his retirement from DOC in 2005, Merton was confident that the kākāpō population was on an upward trajectory, and in the 2019 breeding season kākāpō numbers passed 200.

International island work

Merton was involved in several significant international conservation programmes in the Indian Ocean, using skills and techniques he had developed in New Zealand. From 1977 to 1979 he was seconded as the first Australian government conservator on Christmas Island. In 1983 he led a recovery programme for the noisy scrub bird in Western Australia. Between 1984 and 1989 he worked with the Durrell Wildlife Conservation Trust on various projects in Mauritius, including a recovery programme for the critically endangered Mauritius or echo parakeet and rabbit eradication on Round Island. Beginning in 1992, at the request of BirdLife International, he helped with recovery actions for the endangered Seychelles magpie robin, and he later organised eradication operations for rats, mice and cats on several islands in the Seychelles.

Recognition

Merton received numerous awards and international recognition for his conservation work. These included a Queen’s Service Medal in 1989 for the conservation of endangered species, and the Sir Charles Fleming Memorial Award for Environmental Achievement from the Royal Society of New Zealand in 1990. In 1992 Massey University conferred an honorary Doctor of Science degree on him, and in 1998 he was elected to the United Nations Environment Programme Global 500 Roll of Honour. In 2011 he was made a Fellow of the Ornithological Society of New Zealand and awarded the World Parrot Trust’s Carolina Medal. He died in Tauranga of pancreatic cancer shortly afterwards, on 10 April 2011, aged 72, survived by his wife and son. 

How to cite this page:

Alison Ballance. 'Merton, Donald Vincent', Dictionary of New Zealand Biography, first published in 2022. Te Ara - the Encyclopedia of New Zealand, https://teara.govt.nz/en/biographies/6m13/merton-donald-vincent (accessed 8 October 2022)