Orange-fronted Parakeet

Forest and Bird, Issue 311, 1 February 2004, Page 16

Orange-fronted Parakeet

GEOFF KEEY

Shortly after its identification as a separate species, this bird is on the brink of extinction,

writes

he orange-fronted parakeet is on the verge of extinction barely four years after scientists found it to be a separate species. Ironically, the bird has fallen victim to stoats and rats in an area specially managed by the Department of Conservation as a ‘mainland island’ Orange-fronted parakeet, long argued to be a cross between red-crowned and yellowcrowned parakeet, live in three tiny areas of the Southern Alps in North Canterbury. Established by DNA testing in 2000 as a separate species, the birds were once widespread in the South Island and Stewart Island and some northern islands. The remnant population in the South Branch of the Hurunui River, inland from Lake Sumner, were at the centre of a specially managed area where the Department of Conservation conducted intensive pest-control work to protect the parakeet, and populations of yellowhead and great spotted kiwi. Yet still the birds were lost. Only four years ago there may have been 700 orange-fronted parakeets here, and in the Hawdon Valley across a mountain spur in the catchment of the Waimakariri River; now they may number less than 150. One more year of intense predation could drive them to extinction. The reason for the collapse is a natural cycle of the forests affecting food supplies for pests as well as the birds, and the fact that DoC did not consider the South Branch to be vulnerable to rats. Orange-fronted parakeets live in only three valleys in the lee of the Main Divide. The mountains here have softer edges than the steep walls and high glaciers of the

peaks further south. The ridges are more rounded, with wavy tussock tops to craggy summits. But winter is still hard and the nor wester wind screams down the valleys during spring storms. In places long shingle screes stretch from mountain tops to valley floor, but generally mountainsides are clothed in beech forest.

Small-leaved mountain beech trees cling to the mountainside while valley floors are dominated by massive red beech trees. Their rough-barked trunks tower above buttressed roots. Green moss smothers the ground. It is the nature of these beech trees which triggers the problem — the phenomenon

known as ‘beechmast’. Like many trees, beech produces only a little seed in some years and lots of seed in others. This cycle of changing productivity is called ‘masting’; the productive years are called ‘mast years’. (You may have noticed the same cycle with a favourite garden fruit tree. Years of disappointment are followed by years of abundance.) So it is for the wildlife of the forests. After lean years, mast years provide extra food for breeding birds. Unfortunately, bumper years for birds are bumper years for pests too. Mice and rats feed on the prolific beech seed and breed rapidly. They provide a ready food source for stoats which also breed rapidly. As the population of rats and stoats grows, so does the predation on birds. Hole-nesting, ground-feeding birds, such as orangefronted parakeets, become ready prey for burgeoning rat and stoat populations. Two summers ago, in a ‘mast’ year, rats took the Department of Conservation by surprise. ‘In the Hurunui before 2001 our monitoring never recorded rats. There had been mouse population explosions before [for example in 1995-96], but not rats, says Richard Suggate, DoC’s North Canterbury area manager. The absence of rats meant there were no control programmes in place. When rat numbers escalated rapidly, DoC didn’t have a system to cope effectively with the exponential population growth. ‘We intervened with a programme of trapping that mirrored the stoat-trapping programme, but we were unable to keep on top of the rats. Rats also remained throughout the winter, when birds remain vulnerable in nesting holes, Richard Suggate says. ‘Birds go higher up the hill-slopes in winter. DoC had no resources for a programme on the hill-slopes at that time

— it would have taken a very large effort and we did not sufficiently understand the dynamics of the rat population. We had never before experienced the survival of many rats over winter, he says. ‘That winter the rats did a lot of damage to both the mohua [yellowhead] and kakariki [parakeet] populations, he says. The result has been a dramatic decline in the orange-fronted parakeet population and the prospect of its extinction. It is possible that orange-fronted parakeets could be extinct within the next couple of years. DoC has now begun a rescue programme to try to prevent the extinction. This is centred on extensive pest control to reduce predation and an attempt to establish a captive-rearing programme so that orangefronted parakeets can be transferred onto Chalky Island in Fiordland. ‘Rat monitoring traps and tracking tunnels on the lower slopes of the Hawdon

Valley [Arthur’s Pass National Park] and South Branch, Hurunui Valley [part of the Hurunui "mainland island" ], are the core of the programme. This complements existing possum and stoat monitoring and control, explains Richard Suggate. ‘Monitoring is showing a few rats at present. If rat numbers increase, we will match escalating rat numbers with increased trapping at hot spots. The aim is to nip any outbreak in the bud, he says. DoC is using trapping first, so it can check whether rat numbers initially continue to increase or decrease again. Should trapping prove insufficient, bait stations or bait bags will be used. DoC has already prepared an Assessment of Environmental Effects (AEE) — a legal requirement for this poisoning — for the use of brodifacoum (Talon). An AEE for 1080 usage is being prepared. DoC is also looking at other products (for examples, Racumin, cholcalciferol, or diphasinone) because they do not want to be inhibited in their choice of poisons. ‘Bait can be deployed in a matter of weeks. Bait stations can carry 1080 or other rat-specific products, Richard Suggate says. DoC is also considering the creation of a buffer zone around the core area, by aerial drops of 1080 poison, and is preparing a risk assessment for this. DoC is reluctant to use aerially sown bait within orange-fronted parakeet habitat because, to prevent bait shyness among rats, the baits would be laid without a bird repellent. As the orangefronted parakeets feed in the lower forest level they may take the baits for food. ‘The reason for a buffer zone is that we want to maximise the rat control but minimise the risk of uptake of aerial 1080

Orange-fronted parakeet are more vulnerable

Orange-fronted parakeets eat a variety of foods; their diet matches the cycles of the forest. In the spring, the birds eat invertebrates and beech flowers. In summer, they will eat new shoots if forced to, but prefer beech seed if available. Orange-fronted parakeets feed on the ground as well as in the trees and it is thought that this makes them more vulnerable to predation than the yellow-crowned parakeets that feed higher up in the branches of trees. Only four nests of the orange-fronted parakeet have ever been found so there is little information about their breeding habitats. They nest high in the hollow trunks of trees. Breeding begins in summer and can continue into winter if there is plenty of beech seed. Eggs take 21-26 days to incubate. The chicks are fed at first by the female, and later by the male as well. They fledge from the nest when they are 40-50 days old.

baits by parakeets, Richard Suggate says. At time of writing, the size of the buffer zone is being assessed. Orange-fronted parakeet were seen in the nearby Poulter valley last summer, and there is the possibility they may be located in others adjacent, such as the Esk. Possums are controlled within the orangefronted parakeet areas to maintain the quality of the vegetation, but are considered less of a direct threat to kakariki as they usually cannot get into the holes where the birds nest. ‘In the Hurunui we have used ferratox and 1080 in bait stations. Bait stations are placed along the bush edge every 100 metres. Changing the poison prevents bait shyness. ‘The system along valley-floor margins is successful at reducing possum numbers over the whole hillside. This is because of the high mobility of possums. Possums move in to replace those killed. We are confident that it has kept possums in low numbers (less than three caught per 100 trap nights). DoC is also controlling stoats through existing trapping operations in both valleys. ‘We run trap lines using hen eggs as a lure for stoats every 100 metres along the forest edge and up side creeks for 200-300 metres. In the Hurunui prior to 2001 we used 1080 poison in eggs. We changed from 1080 to traps, as the "experimental-use permit" for using 1080 on stoats had expired and by trapping we can obtain a better count of stoat numbers. ‘We use chocolate buttons to attract rats SO we can catch them in the same system that we use for stoats. There are now a total

of nearly 1000 rat-trapping stations deployed in the Hurunui’ A programme of counting orange-fronted parakeet and nest identification will also occur in the Hawdon and Hurunui throughout the summer, to build up a picture of the population and to assist efforts to locate eggs for captive rearing and subsequent release. The need for this programme illustrates the severe plight of New Zealand’s forest birds. It also raises questions about the impact of rats on forest birds and ecosystems away from the protection of the intensive predator control practised only in the few ‘mainland islands’. At the beginning of December 2003, the Department of Conservation and the various ministries for the Environment, Fisheries, and Agriculture and Forestry, released a discouraging annual report on the implementation of the Biodiversity Strategy. This strategy sets the direction of Government action to protect New Zealand’s native plants and animals for the next 20 years. The report concluded that New Zealand was failing to protect its native plants and animals. Although current Government and community action was slowing the decline in New Zealand’s biodiversity, it was not halting it. The report identified that efforts to protect nature were being hampered by a lack of knowledge and funding — problems that have haunted efforts to protect orangefronted parakeets and their habitat.

— GEOFF KEEY

is a conservation officer with Forest

and Bird. The Hurunui ‘mainland island’ and orangefronted parakeet were the subject of articles in Forest & Bird, in November 2000.

Pacific Parakeets in Peril

ntil news broke of their critical | orange-fronted parakeets were unknown to most New Zealanders. Long thought to be a variation of the more common yellow-crowned parakeet, the orange-fronted is now recognised as an individual species. Genetic research published by the Department of Conservation in 2001 reveals that orange-fronted parakeets share a more recent common ancestor with New Zealand’s redcrowned parakeet rather than with the yellow-crowned parakeet. New Zealand’s parakeets (or kakariki) belong to the genus Cyanoramphus, which also includes seven other species and four subspecies distributed throughout the South Pacific. Cyanoramphus parakeets occupy a wide range of habitats from the wet and windswept subantarctic tussocklands of the Auckland Islands to the lush tropical rainforests of New Caledonia. The Cyanoramphus genus appears to have originated in Australia and spread throughout the South Pacific, diversifying into the many species we know today. Molecular data suggests that New Zealand’s parakeets arrived here from Australia via New Caledonia between 450,000 and 625,000 years ago. Unfortunately, the spread of people and their associated pests through the South Pacific has taken its toll on parakeets; three species and one subspecies are now extinct, lost from the Society Islands, Macquarie Island and Lord Howe Island. In the 1800s, orange-fronted parakeets were found throughout the South Island, Stewart Island and a few northern offshore islands. Now they are found only in three valleys within Arthur’s Pass National Park and Lake Sumner Forest Park.