Are mice taking the mickey?

Predator Research

The idea of this posting or thread will be to gradually collate the mouse research that may be relevant to eventually protecting some rock wren habitat...this is a work in progress!! If anyone stumbles on this and can provide any more information to help me out please leave a comment...just an attempt by a layman to get his head around the issues!

Mice:

Potential conservation impacts of high-altitude small mammals: a field study and literature review...Includes very good info on mice diet

Researchers Measure Extent of Mouse Menace: Landcare Research scientists investigate mouse abundance in the context of beech masting...press release

ERADICATING HOUSE MICE FROM ISLANDS: SUCCESSES, FAILURES AND THE WAY FORWARD....good references to check out further

link to mouse trapping discussion on the wildlife management forum

Mustelids:

Movement, diet, and relative abundance of stoats in an alpine habitat
Smith, Jamieson 2003 - suggests independent populations beech/alpine and stoat switch to weta from mice in event of mouse decline after mast cycle

Selection of alpine grasslands over beech forest by stoats (Mustela erminea) in montane southern New Zealand

Dispersal and survival of juvenile feral ferrets
Lancare Research scientists investigate the dispersal of young ferrets and provide some management recomendations...journal article

Just how unique are the New Zealand wrens?

I have been periodically searching around for interesting Tuke stories, or experiences to add to this blog. The general fruitless of this search, if you exclude the occasional encounters of bird tickers (I'm sure there is a term for this I can't remember!) with the much photographed Tuke of Homer Tunnel, has emphasised to me how little our worlds interact. We live down in our cities, venturing out only occasionally to poke our noses into the bush. They live up there in the alpine world, sheltering in the giant clumps of rock and hopping around alpine basins in the sun, just as they have been since the Southern Alps started rising. Indeed it seems that going back in time is necessary to understand one of the reasons for why the tuke is so special.

Peter Gaze, a DOC Scientist in Nelson, plucked me an excerpt from "Consider the Birds - who they are and what they do" by Colin Tudge 2008. It begins to elucidate just how unique the tuke and its sister the titipounamu (or rifleman) are from an evolutionary perspective,

The New Zealand wrens, family Xenicidae should be treasured not simply as fine little birds but because of their unique evolutionary status. About 80 million years ago, so it seems, the world's first population of passerines split into two. One group evolved to become crows, shrikes, finches, swallows and all the rest - 6000 species of all shapes and way of life. All that remains of the other group is the New Zealand wrens."

Around 80 million years ago is about the same time that New Zealand (then a province of Antarctica) broke away from the great southern land "Gondwana". I only know this in detail because one of my current reads George Gibbs in "Ghosts of Gondwana" says so. Gibbs also notes the importance of the New Zealand wrens, here refered to as of the family Acanthisittidae...

A molecular study has revealed that our tiny acanthisittids possibly represent the closest surviving relict of the ancestral type of passerine bird

Now to be honest this doesn't really mean much to me at all, a layman in a bird mans world, but think of it this way. There are, or were, three endemic (only existing in New Zealand) vertebrate "orders", represented by the Moas, the Kiwis and the Tuatara. There are only nine endemic vertebrate families, these include our wattlebirds (eg kokako or saddleback), our family of frogs, and our special short-tailed bat of the family Mystacina. The frogs are an interesting comparison actually they have existed for a similar period of time to the wrens, have four existing species to the wrens two and three species already extinct to the wrens four.

We have 90 million years of history in our hands...

Some random info....

A while back some friends and I organised a Mountain Marathon (a two day tramping navigation event). We hoped with this to raise some money for Tuke conservation. In the end we didn't raise anything, but we had fun and so did the competitors exploring the beauty of the new Hakataramea Conservation Park.

For their interest I chucked out a couple of little articles about Tuke and the New Zealand wrens in general with some links. I have reproduced them below.

The NZ Wrens in History(16 April 2008)

Bush wren, the only colour photo that will ever be taken. Don Merton

Ok. So according to Kerry-Jane Wilson's catch-all of NZ conservation "Flight of the Huia" there were six species of New Zealand wren and they were all adapted to their own ecological role and often existed side by side.

There were the Stout Legged Wren and the Long Billed Wren, who existed sometime in the past and are known by the fossils. Then theres the Stephens Island Wren whose final population was famously exterminated by a lighthouse keepers cat, for a slightly more elaborate story check out this:

No4 into the eternal grave of extinction was the Bush Wren, which I would like to briefly elaborate on.

In 1963/64 an ecological cataclysm, in the form of rattus rattus, invaded Big South Cape Island (now known as Taukihepa) and neighbouring islands. Muttonbirders reported a rat plague and wildlife officers were sent quickly to investigate, despite their findings and recomendations to act, scientific and political inertia led to delay and the extinction of three unique species; the greater short tailed bat, the Stewart Island Snipe and the Bush Wren.

The greater short tailed bat, people don't really know that much about, and much the same can be said for the Stewart Island Snipe, although its aerial displays are thought to be the basis of the Maori legend of the Hakawai.

Interesting following rat eradication snipe have been reintroduced to nearby Putauhinu island. However these are Snares Island Snipe, which have not been observed following this aerial display. The Hakawai has been silenced.

But to get onto the bush wren. The wildlife serice team managed to relocate six individuals to nearby Kaimohu island where they were unable to re-establish. The last was seen in 1972. The team which included well known conservationist Don Merton had successfully saved the South Island Saddleback at the same time and used this experience most famously in the subsequent miraculous campaign to save the Black Robin.

But couldn't do anything to help the bush wren. So now theres two NZ wrens left the rifleman and the rockwren, so we better keep an eye on them!

Introduction to the Rock Wren and its conservation issues (9 April 2008)

The New Zealand wrens family...only two left.

As a New Zealander mad keen on the outdoors I have always been aware of the rock wren or "Piwauwau"(or Tuke..ed). They tend to pop up in the most beautiful places; the Darrans in Fiordland, high above the Matukituki in Aspiring, Mueller Hut in Mt Cook. I remember being surprised on a circumnavigation of Kahurangi in 1999 to see the study site mentioned further on, on the Mt Arthur Tabelands.

However, it was not until a short time spent working for DOC helping manage the subantarctic and offshore islands that I became aware of the potential threats facing this amazing little bird; lack of information, apathy/transferrance of risk, and predator invasion of tussocklands and alpine areas.

Now firstly I'm no ecologist, strictly an enthusiast, and I don't claim any scientific credibility whatsoever. My goal for this website is to bring some information together from the best sources I can find, chuck around a few whacky ideas and hopefully be informative and amusing at the same time. The information may not always be coherent or structured but it will be on this site all together for everyone to see. I plan to use the information to publish appropriate articles to a wider audience via the mainstream media.

LACK OF INFORMATION: The first thing you become aware of when you are working for DOC is the quality of information decisions, or more importantly strategies, are based on. Population numbers and trends for even many bird species are virtually non-existent, the blue duck springs to mind, but so to does the rock wren (I haven't found any yet apart from the small study in Kahurangi although further research may throw some up). DOC is simply not resourced enough to do this work.

There is also a lack of information for advocacy, looking on the internet I found a brief introduction to the rock wren: http://www.nzbirds.com/birds/rockwren.html which quotes the eminent, but pre World War 2 naturalist, Herbert Guthrie Smith writing "the rock wren may be considered as relatively safe". Chronologically that was followed by a reference to a Notornis article of 1954 describing the species as "common".

However I remember from my time in DOC that they were trialling a rock wren transfer to Anchor Island (something you do when you recognise a species is in danger). This was confirmed by a 17th Feb 2005 news article on www.biodiversity.govt.nz "having a population of rock wrens on predator-free islands is an extra safety measure for the species, just in case something major happens to populations on the mainland". But then checking out Te Ara, our online encyclopedia I find that "a 2005 attempt to establish a population on predator free Anchor Island in Fiordland was unsuccessful".... Mental note contact DOC Te Anau and find out what prompted this attempt and why was it unsuccessful.

Two more leads to follow up were, - NZ National Parks and Conservation Foundation: "S.O.S" fundraising campaign, launched early 2007, focused on six species including rock wren.
- November 2003, Forest and Bird magazine article on fast disappearing rock wren.

APATHY/TRANSFERRANCE OF RISK: As a nation we have delegated our moral task of protecting threatened species to DOC. We largely pass them the burden and forget about it, this is especially true for species, such as the rock wren, that exist only on public land. At an individual level the typical reaction in DOC is to do as much as they can. For political reasons what they can't do tends not to get noticed or publicised. DOC's advocacy role in promoting the needs of these species or indeed eco-systems is also compromised by politics, prioirities and mainstream media policies.

In a Global Economic Forum Report I was perusing recently "Travel & Tourism: Competitiveness Report 2008” (thanks to www.infonews.co.nz for the link). New Zealand ranked 130th in the world for its care of threatened species. Now this is probably due to the sheer number of threatened species on our books and our inability to improve their status in the face of continuing predation. But it is also a reminder of the great responsibility we have as a nation to focus on this work.

PREDATOR INVASION OF TUSSOCKLANDS AND ALPINE AREAS: Through the Tenure Review process huge areas of tussocklands are being returned into public ownership, including significant parts of the mountain marathon course for this year. I love these areas but walking through them you sometimes wonder, what is the point of protected areas if by the day they are becoming more and more devoid of biodiversity. If the interest at a macro scale of light interplay on broad ridges and snowy mountains isn't matched by bird song or invertebrate activity at a micro level.

I still have a "Biological Conservation" article I found while working for DOC "Introduced house mice: a significant predator of threatened and endemic birds on Gough Island, South Atlantic Ocean”. It gave me the heebie jeebies. We lay people tend to think of predator/prey relationships as stable but this is far from the case. In the article above scientists observed the adaptation of mice to direct predators of seabirds and their eggs. For me that was relevant at the time as mice are still present on some of our most precious nature reserves, such as Antipodes Island, and it remains relevant now as a more dynamic way of seeing conservation.

There’s some more serious science done on alpine invasion, this report: http://www.doc.govt.nz/upload/documents/science-and-technical/drds248.pdf

Focuses on the potential of a good flowering season for tussock allowing predators like stoats to go to higher altitudes because of the increased presence of mice etc, which could obviously impact the food supply and life expectancy of the rock wren. While predator trapping work done on the Mt Arthur Tablelands has coincided with a recovering population of rock wren see http://www.fof.org.nz/newsletter%20nov06.html (I now know the accuracy of this last statement is questionable...ed).

A Measurable Goal.

I'm happy now, I have a purpose and a measurable goal to help the Tuke. In 2009 I am going to run a campaign to attempt to have the Tuke elected as New Zealand's Bird of the Year.

The bird of the year has been run since 2005 by Forest and Bird and I checked in yesterday with Helen Bain, their communications manager in Wellington, to check on Tuke's voting history. Helen wished me luck, and told me I would need it.

"In 2008 (the Tuke) got 10 votes and in 2007 it got four. (I don’t have the figures before that.)"

So there is definite potential for progress!

I came to this goal the long way round, and it is only an intermediate step, because being more widely known in itself will not improve the endangered status of the Tuke. I originally was thinking about a predator trapping program in Arthurs Pass, specifically the Otira Basin, but there are complications with that, which need to be worked through, principally the effects of mice, which may be exacerbated, if stoats are trapped for - but that project is lurking in the background to be thought about and discussed more.

But its important to have a measurable goal and this is it for the meantime. Any strategies or ideas welcome that may ensure Tuke's election, but I have a few up my sleeve.

Ornothological Society Press Release 24/07/08

MEDIA RELEASE

Thursday 24 July, 2008

Endemic alpine bird declining

A recent study shows the rock wren or tuke is declining in numbers and in range.
Sue Michelsen-Heath (University of Otago) and Peter Gaze (Department of Conservation) have studied all known records of the diminutive and unique alpine bird and published their findings in the journal Notornis.

Over 2100 records were gathered from between 1912 and 2005 from a wide range of sources including
DOC, the Ornithological Society of NZ (OSNZ) and tramping and alpine clubs, prominent naturalists and many nature enthusiasts.

A map of all rock wren sightings shows a 24% reduction in the area they have been found in since 1984. Gaze said “It could be that local populations are so low they are not being spotted. The birds are also hard to detect because of their small size and their camouflage. This makes it difficult to quantify changes in population size.”

Michelsen-Heath said “Changes in the popularity of different types of outdoor recreation over the pastcouple of decades has contributed to a reduction in rock wren reportings. But predation by mice and stoats is the main factor.”

Fewer reports of rock wren sightings could be due to fewer people doing once popular exploratory tramps.More people are kayaking and white-water rafting. Furthermore, DOC now uses contractors to maintain back-country tracks so many staff are not regularly out in these remote areas.

Gaze said “It could be that they are no longer present in some areas, or that people aren’t looking as hard, or perhaps people are not reporting sightings or visiting some of these areas anymore.”

Michelsen-Heath said that consistent anecdotal accounts of decline, evidence of predation by stoats and mice, unsuccessful searches in previous strongholds, and the recent post settlement extinction of five other New Zealand wren species are a real concern and do not bode well for the bird’s future.

The study’s authors also hold fears for the effect climate change on the species. Rats may start colonising alpine areas as these areas become warmer, and prey on rock wren. It is unknown how climate change could affect the diversity and abundance of insects that the bird feeds on.

Michelsen-Heath said “We’d love to see regular reports of birds coming in from trampers, climbers, hunters and outdoor adventure guides, as well as from DOC staff and bird watchers, showing the birds are still alive and well in these areas.”

“The more records we receive, the more confident we will be that we’ve got the real picture” said Gaze.

The public should report sightings of rock wren including a GPS or map reference to their local DOC office, or enter their recording directly into eBird – OSNZ’s online database (www.eBird.com/nz).

Gaze said “The results confirmed what we had expected. People were saying they weren’t seeing them as often, or weren’t seeing them where they had in the past. So we tried to look at anecdotal evidence scientifically. The results give us justification to be concerned.”

Background

• Results show that rock wren may have disappeared from: Douglas Range in Kahurangi National
Park, Kaikoura Mountains, Paparoa National Park and Lewis Pass.

• Numbers appear to be declining in: Mt Aspiring National Park, Henderson Range in Kahurangi
National Park, Murchison Mountains.

• The remoteness, high altitude and vastness of the Southern Alps make it extremely difficult to
control predators such as stoats and mice. Currently there is no way to control these pests on a large scale within rock wren habitat.

• With the help of a large donation, DOC has translocated some rock wren onto two predator-free
islands in Fiordland.

• How to identify rock wren: Smaller than a silvereye, but with similar colouring. Males are olivegreen,females are more slatey-brown below, have a very short tail, long legs, rounded wings and destinctive cream ‘eyebrows’. They can be identified by their high-pitched, simple three-note call.

• Where rock are found: Alpine basins of the Southern Alps, among rock falls, scree slopes and
subalpine scrub.

• Rock wren behaviour: It bobs up and down among rocks and subalpine scrub feeding on small
insects. It runs and hops and only flies short distances. It nests in holes.

• The only ‘true’ alpine bird in NZ, breeding and living in the alpine zones all year round.

• The rock wren or tuke (Maori name) is endemic to NZ meaning it is a native species and found only in NZ.

• Rock wren are classed as 'nationally vulnerable’, one of three criteria for threatened species in NZ. This status is due to the relatively small total population and the expected continued decline in abundance. Rock wren’s global status is ‘globally threatened.

• The rock wren belongs to a distinct family [actually ‘Infra Order’] of birds that is known only from NZ. A hundred years ago there were five species in this family but now the rifleman and rock wren are the only survivors. The rock wren and rifleman’s ancestors separated from all other bird families about 90 million years ago.

• Notornis is a scientific journal published quarterly by the Ornithological Society of New Zealand

Rock wren sightings sought as figures fall

The following article appeared in the ODT on Tuesday 30th December, thanks to them for permission to reproduce the article that can also be found here

Rock wren numbers appear to be declining and trampers, climbers and hunters are all being called upon to report any sightings they might make of the diminutive threatened native bird.

The rock wren, or tuke, is classed as nationally vulnerable, and the results of a study have shown numbers appeared to be declining in Mount Aspiring National Park, in the Murchison Mountains and in the Henderson Range in the Kahurangi National Park.

University of Otago teaching fellow Sue Michelsen-Heath, of the zoology department, studied more than 2000 sightings of the rock wren recorded between 1912 and 2005.

The results of analysing the sightings showed areas the tiny alpine bird inhabited had declined by 24% since 1984.

Predation by mice and stoats was a major factor in population decline, she said.

Anecdotal evidence of population declines, evidence of predation, unsuccessful searches in previous strongholds and the extinction of five other New Zealand wren species in the past 100 years did not bode well for the bird's future.

Department of Conservation technical support officer Peter Gaze said climate change could also affect the rock wren, as rats could start to colonise alpine areas as they became warmer.

The wren is the only true New Zealand alpine bird which breeds and lives in the alpine zones all year round.

It was difficult to quantify changes in population size as the bird was hard to detect because it was small and well camouflaged.

The rock wren is smaller than a silvereye, but has similar colouring. Males are olive-green while females are more slatey brown.

The birds have a very short tail, long legs and distinctive cream-coloured eyebrows.

They are found in alpine basins of the Southern Alps among rock falls, scree slopes and subalpine scrub. They can be identified by their high-pitched, simple three-note call.

Sightings, with a GPS or map reference, can be reported to Doc or entered on to the Ornithological Society of New Zealand's website www.eBird.com/nz.

The findings of the study were published in the society's scientific journal Notornis.