Kaituna River victory

Forest and Bird, Issue 281, 1 August 1996, Page 8

Kaituna River victory

Ann Graeme

BAY OF PLENTY conservationists and iwi are delighted with a High Court decision that allows the Department of Conservation to divert part of the Kaituna River to restore some of the natural flow to the Maketu estuary in the Bay of Plenty. Forty years ago the Kaituna River was diverted away from the estuary, straight into the sea. With no river to flush it, the estuary began slowly filling with sand until it was unable to support its former rich populations of sea and shore life (see last issue of Forest & Bird, page 8). A channel with four culverts and gates was completed by DoC last October to restore water to the estuary. But court action by a disaffected land owner led to delays and then to direct action by local residents in February to force open two of the gates. While the court judgement confirmed DoC’s right to restore water to the estuary, the Maketu Action Group has said

that it will continue to work for an even larger flow to be returned.

Update on New Zealand dotterels

PROBLEMS BESET most of our native birds, but few can have as many difficulties to contend with as the New Zealand dotterel. Nesting on sand spits of northern beaches, dotterel nests fail because of disturbance and destruction from dogs, dune buggies and careless people. Understanding these impacts has led to successful beach warden schemes by DoC and Forest and Bird to protect nesting sites in popular areas during the busy summer period (see Forest & Bird November 1992). But that is not the end of the dotterels’ problems. Their nesting places continue to shrink as new subdivisions smother increasing areas of the Coromandel and Northland

coastlines, and even protected sites like the Ohope spit in the Bay of Plenty are eroded by high seas. Cats, rats and hedgehogs prey upon eggs and chicks, and recent video surveillance has shown southern black-backed gulls stealing eggs and harassing dotterel families. On Matakana Island, the largest dotterel breeding site in the Bay of Plenty, gulls, grown fat from the nearby rubbish tip, multiplied and their nesting colonies overran dotterel nest sites. Last winter, in a culling programme, more than 3,000 gulls, about 70 percent of the population, were killed with alphachloralose, a humane narcotic poison. The result? A record number of 17 dotterel chicks peacefully fledged. In the absence of gulls, dotterel behaviour changed dramatically. Territories were up to three times larger and adults took chicks to the water edge to feed when previously they had been kept close to the cover of

the dunes. For the first time, parent birds were observed resting with their eyes closed, when previously they had been constantly awake and flying at gulls passing overhead. That was the only good news for North Island dotterels last year. The birds nest just above the high tide mark and in November, spring tides combined with storms washed away many nests from Northland to East Cape. Then, just as the birds were re-nesting, another very high tide in December wiped them away again. As a labour of love, Forest and Bird member Bev Woolley monitored the Coromandel birds, and provided assistance, advice and fencing material to locals minding the dotterel nests on their beaches. However at Opoutere, the major nest site on the Coromandel, high tides and inadequate wardening saw only six chicks banded, the fewest for many years. Research by Andrea Lord

prompted DoC’s New Zealand Dotterel Recovery Group to recommend that the dotterel fence on the estuary side of the Opoutere spit be extended to close off public access, so chicks can feed undisturbed. Andrea also recommended that a distance of 80 metres from the nest be roped off to prevent human and canine disturbance. Behind the beaches at the Auckland Regional Park of Tawharanui, 400 hedgehogs have been killed over the past four years, yet dotterel eggs continue to be taken. The extent of the dotterel nesting failure at Tawharanui was highlighted by John Dowding who monitored 24 dotterel pairs and reported that only two pairs fledged chicks, a quarter of the eggs being inundated by the high tides and the remainder lost to predators. His video surveillance of nests revealed a raiding cat, a spur-winged plover casually demolishing an egg laid in the plover’s territory, and hedgehogs eating the eggs, night by night, as they were laid. Further south there is encouraging news from Stewart Island. The southern New Zealand dotterel is now recognised as a separate subspecies and is our third rarest bird (after fairy tern and kakapo), and amongst New Zealand’s five most endangered birds. Wild cats destroy nests and kill sitting adult birds, resulting in an alarming scarcity of males in the tiny population, because the male birds incubate the eggs at night and tend to fall victim to the cats. From a low of 65 birds in 1994, the population has risen to 93, the highest since 109 were recorded in 1990. More funds for the southern dotterel have at last been made available to DoC so that this summer the rugged hinterland was comprehensively explored and many of the dotterel’s mountain-top breeding sites were recorded. This will allow further cat and rat control to be carried out, as well as on Table Mountain where the indefatigable John Dowding has long struggled to assist this neglected bird.