Conservation projects

Stoats

Department of Conservation biodiversity staff are carrying out an intensive stoat trapping programme on the Milford Track and side valleys, funded through the Department’s Operation Ark fund.

Stoat

Stoats were introduced to New Zealand in the 1880s to control the explosion of rabbits, another introduced animal. Prior to this time New Zealand’s native birds had enjoyed an environment free of predatory mammals. The introduction of stoats has seen a steady decline of bird species in the New Zealand bush and today the stoat is considered the greatest threat to many species.

The stoat control programme began in the Clinton Valley in 1999 and in the Arthur Valley in 2003 to investigate the effects stoats were having on the populations of whio (blue ducks) in the Milford Track area.

Stoat traps are placed at approximately 200 metre intervals along the length of the track and up some side valleys. During the three years of study when no stoat control was carried out in the Arthur Valley approximately 25% of the adult females were killed by stoats and no ducklings fledged. Over the same period trapping in the Clinton Valley caught 576 stoats.

With stoat control in place, many nests now successfully fledge ducklings. However, some nests are still lost in floods during the nesting period (September – November).

The stoat control programme is now ongoing in both valleys. River surveys are carried out twice a year to determine the number of juvenile birds produced. Results show that the whio population is recovering quickly.

Trapping has also benefited other bird life in both valleys with increases in the numbers of whio (blue duck), kaka, kiwi and weka (woodhen) to name a few.

Whio

Whio (blue duck)

The whio (blue duck) is a unique and endangered species. It is endemic to New Zealand and has no close relatives anywhere in the world.

It is blue-grey in colour with a reddish-brown spotted breast, a pale pink bill and yellow eyes and weighs about 800-1100 grams.

Living in fast flowing streams and rivers whio are often seen standing on rocks or feeding on fresh water invertebrates. Whio remain in territorial pairs all year. The female call is a low rattling growl, while the males call of “fee-o” gives the duck its Maori name.

On the Milford Track whio can often be seen at Clinton Forks, near Mintaro Hut, at the lower end of the airstrip near Quintin Hut and near Dumpling Hut.

The Department of Conservation gratefully acknowledges the support of local tourism company, Real Journeys, with the Whio Recovery Programme in Fiordland.

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