24 Jan 2021

Cape Farewell ecosanctuary progressing despite setbacks

12:58 pm on 24 January 2021

A global pandemic and the virtual destruction of a rare bird colony has not deterred a group creating an ecosanctuary on the northernmost tip of the South Island.

Guests at the opening ceremony take a walk through the sanctuary at Cape Farewell.

Guests at the opening ceremony of Wharariki Ecosanctuary at Cape Farewell in January 2020. Photo: RNZ / Tracy Neal

The Wharariki Ecosanctuary at Cape Farewell was opened in January 2020.

It was hoped to have new new seabirds roosting at the sanctuary by now, but Covid-19 set back plans for the re-introduction last year of a variety of seabirds that were once there in abundance.

The sanctuary was formed through a partnership between HealthPost Nature Trust, Manawhenua ki Mōhua and the Department of Conservation.

Trust chair Peter Butler said despite the setbacks, including the discovery of an almost-destroyed colony of fluttering shearwater, they had achieved a number of conservation goals.

He said they made a grim discovery in October that a previously considered healthy population of fluttering shearwater on a nearby small island had been almost wiped out by what appeared to be a rodent predator.

The Trust hired a helicopter to land three seabird experts on to rock stack south of the sanctuary, called Nguroa Island.

The aim was to assess whether it could be a source of fluttering shearwater and diving petrel chicks for reintroduction to the mainland via the ecosanctuary.

"A survey in 1997 had established that there was a colony of about 5000 pair of these seabirds on this island. Our October expedition found we only about a dozen pair left."

Butler said it appeared that predators had crossed to the island in an extreme tide and caused a massacre.

"It was a real blow for all of us, but it really brought home how critical the protection work we're doing is."

They now planned to intensively trap the shoreline adjacent Nguroa Island to give the remnant population a chance to rebuild.

A plan was also under way to re-introduce the threatened flesh-footed shearwater to the ecosanctuary by late autumn.

"We've got our eyes set on something with the 'slightly creepy' name of flesh-footed shearwater, which are threatened, so we're investigating the possibility of re-introducing them in the late autumn."

The 200m predator fence at the Wharariki Ecosanctuary.

The 200m predator fence at the Wharariki Ecosanctuary. Photo: RNZ / Tracy Neal

Butler said despite everything, the trust had managed a list of achievements this year include conversion of a former DOC house at Farewell Spit into a field station and the appointment of a field co-ordinator who has organised groups of volunteers to plant trees and service trap networks.

"We had two hundred large double traps made up at the Menzshed-Nelson/Whakatu over the winter that we have deployed in new trap lines.

"We now protect from the southern end of Wharariki beach on the West Coast all the way to Puponga in Golden Bay , in several lines, creating a 'virtual fence' across this narrow corner of the South Island," Butler said.

He said the traps, designed to catch rats, stoats, the "odd weasel" and wild cats, but prevent curious weka from poking about were not able to be checked during Covid lockdown.

"We've got two or three lines of traps running from the Tasman Sea to Golden Bay which should protect Farewell Spit."

He said they were surprised at the "enormous number" of stoats they were catching - sometimes up to 23 in a trapline with the capacity to catch up to 80 pests. Butler said despite this, it was encouraging that the numbers were not increasing relative to the number of traps.

"That's an indication that trapping is successful and we are getting the predator numbers down."

The special habitat at Cape Farewell is part of the new ecosanctuary.

The special habitat at Cape Farewell is part of the new ecosanctuary. Photo: RNZ / Tracy Neal

This year the Trust had also found a second remnant population of Sooty Shearwaters nesting onshore, and ring trapped the area and eliminated a resident wild pig to enhance their chances of survival.

"Our cameras tell us little blue penguins have occupied some of the empty Sooty burrows," Butler said.

About 3000 trees - mainly cabbage tree, kaikomako and kanuka - have been planted in the ecosanctuary and around Wharariki wetland to enhance habitat and provide bird food.

Butler said they were putting the finishing touches on the new field station house in early December when the first scientist, gecko expert Sam King, turned up for a week of research into the rare Nelson Green Gecko.

Butler said two Victoria University masters students studying the paper wasp problem on the Spit were now in residence for the summer, supported by a stipend from the Trust.