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Source: Department of Conservation

Introduction

About 50 small seabird chicks from the Chatham Islands have been translocated by a volunteer conservation group to predator-free Mana Island, off the Porirua coast.

Date:  11 February 2019

It is the first stage of an ambitious three-year project by Friends of Mana Island to bring back white-faced storm petrels to the island, which is managed by DOC.

A successful first year will mean a further 200 chicks will be translocated over the next two summers, with a total of 250.

Friends of Mana Island president John McKoy says white-faced storm petrels used to live on Mana Island before any people inhabited the island. A few have been sighted there over recent years.  

“This translocation is part of the ongoing restoration of Mana’s original ecosystem based on a plan developed by DOC in 1999.

“Our aim is to establish a colony of white-faced storm petrels on Mana Island to help restore the cycle of nutrients from sea to land, and improve the habitat for other animals and plants,” he says.

For the next three weeks volunteers will hand feed the chicks sardine smoothies and monitor their growth.

White-faced storm petrel chick
Image: Cathy Mitchell | DOC

Each chick is housed in an artificial burrow high on the clifftops of Mana Island. The burrow entrance is gated until the chick is ready to come outside and eventually fly away.

The chicks were carefully selected by wildlife biologist Cathy Mitchell, volunteers and DOC staff, from the source island – Rangatira Island in the Chathams, also known as Hokorereora or South East Island. The island has more than a million breeding pairs of white-faced storm petrels.

Each chick chosen is estimated to be 6-7 weeks old and a minimum of 45 g, the optimum size and age for survival and success.

The journey to reach their new home on Mana Island has involved many forms of transport – a fishing boat from their island colony to the main Chatham Island, a plane to Wellington, a van across the airport, and a helicopter ride to Mana Island.

Representatives from Hokotehi Moriori and Ngati Mutunga travelled with the birds every step of the way from the Chathams, and formally handed them over to Mana Island local iwi Ngati Toa.

The chicks are expected to fledge within the next 7-15 days and fly out to sea. They will stay at sea for three to four years before looking for a place to breed.

Seabird expert Graeme Taylor from DOC says it is hoped some of the birds will return to Mana Island to breed and start a new colony.

“We estimate that about 60 % of the birds that fledge from Mana Island will survive their first year at sea. Petrel chicks need to learn to feed on their own and the first year weeds out a lot of birds.”

He says similar transfers of other burrowing seabird chicks have had return rates to the new colony site of 10 to 40 %.

“Some birds will naturally choose other breeding colonies, although there are none nearby in the Cook Strait region.

“To have a good chance of establishing a new colony on Mana Island we need a critical mass of at least 10 breeding pairs,” he says.

The project is funded and supported by Friends of Mana Island’s major sponsor OMV New Zealand Ltd.


Additional information 

Why bring back these birds to Mana Island?

The aim is to get Mana Island back to being a seabird driven system i.e. birds are part of the cycle of nutrients – from sea to land, they fertilise the land. They dig holes which provide tunnels for lizards and invertebrates. They help develop nutrient rich soil that plants and invertebrates depend on.

Bringing back white-faced storm petrels (WFSP) to Mana Island will add to the diverse species of nesting seabirds already on the island – diving petrels, sooty shearwaters, fluttering shearwaters and fairy prions.

Why bring the chicks from the Chathams?

The Chathams colony is the closest one to Mana Island of any size, and the world’s largest colony of WFSP with more than an estimated one million breeding pairs of WFSP.

There are millions of other burrowing sea birds on Rangatira Island, the source island (sooty shearwaters, broad billed prions and Chatham petrels).

How big are the chicks which were selected?

Minimum of 45 g; wing length of 95-135 mm.

What happens once they are on Mana Island?

  • The birds are weighed and fed each morning (sardine smoothie) and returned to their individual artificial burrows.
  • The burrows are gated to confine the chicks. The gates are removed when the birds are considered big enough to emerge and then fledge (fly away).

When might these birds return?

These birds will mainly return to Mana Island in the spring months of 2022-26.

About white-faced storm petrels

  • White-faced storm petrel Pelagodroma marina.
  • Takahikare-moana (dancing on waves).

White-faced storm petrels are one of the world’s smallest seabirds (approximately 45 g weight). Their small size makes them very vulnerable to exotic predators and they can only breed on predator-free islands. 

Their legs and toes are long and are used to skip and patter along the sea surface as the birds feed. For this reason, they are sometimes called “Jesus Christ Birds” by boaties as they are seen ‘walking on water’, with very little movement of their wings.

Adults return to their colonies to breed in September to early October. They lay a single egg which is incubated for about 50 days. Chicks are left unattended from 2-3 days after hatching and are generally fed every 1-2 days, though periods of up to 7 days between feeds have been recorded.

Previous translocation work

  • Translocations of other seabirds to Mana Island:
    • diving petrels – 1997
    • fairy prions – 2002-04; and 2015 and 2016
    • fluttering shearwaters – 2006-2008.
  • Other birds translocated to Mana Island – bellbirds, kākāriki, kiwi, whiteheads, North Island robins and brown teal. Takahē also breed on the island as part of the national recovery programme.

Who are Friends of Mana Island?

Friends of Mana Island (FOMI) is a volunteer conservation group which supports the work of DOC on Mana Island. 2018 was the 20th anniversary of the group.

FOMI has been involved in previous seabird translocations including the fairy prions and fluttering shearwaters.

For further information, see the FOMI website.

Contact

MIL OSI