An overview of efforts to encourage native bird population numbers between Mt Aspiring and Wanaka, New Zealand.

top: Members of the Matukituki Trust planning trapping operations at Aspiring Hut 10 days ago

Many of you know that I’ve been involved with many others giving native bird populations a leg up via the Matukituki Trust for the last 4 or so years. Progress has been very steady and positive due a good base plan concept, followed up by proven methodology.

Taking a wider view the good news is that four Trusts inc. the Matukituki Trust, several landowners, tourism operators and DOC, are now working collectively in the area from the mid slopes of Mt Aspiring to Wanaka.

Trust maps 1
Traps [in green] recently installed from Wanaka on the left, to Mt Aspiring on the right. Plans are well evolved to fill the obvious gaps in the next few months
Data obtained is being entered into a centralised database that monitors approx. 1600 traps, [Matukituki Trust 620], which enables all to look at and plan for the bigger picture.

Trust maps 3
A high density of traps of all types around Aspiring Hut in the West Matukituki valley, Mt Aspiring National Park [map approx. orientated north]

Trust maps 2Traps of all types upstream from Aspiring Hut in the West Matukituki valley, Mt Aspiring National Park. Liverpool valley on the left, upper west Matuki. and Scott Bivy rock in the center, and French Ridge on the right.

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Many traps are above the winter snow-line in these three areas, with many being of the self resetting variety

I can’t comment yet on all the “kills” but in the last 6 months the Matukituki Trust’s traps have caught 911 predators: cats, rats, hedgehogs, stoats and possums. Mice, despite not directly being predators, are included.

It’s estimated that each predator kills 2 wildlife per week [birds, lizards,, bats insects etc] thus the above kills amount to 47,000 wildlife saved to-date.

Possums do eats chicks and eggs, but this aside 20 of them will eat 2 tons of vegetation per year, so this means that 18 tons are not eaten. That’s 9000 full shopping bags that stay on the trees to benefit the birds.

Trust maps 5A new kid on the block – one of many of the south island robin reintroduced some years back. Breeding has been so successful last spring that it’s hard estimate if we’re talking scores or hundreds of birds that have been bred by about 20.

In the last few weeks contractors have been in the valley to set up transects for annual bird counts, but so far exactly how many has not been released yet.

 

A brief history of the Matukituki Trust:

First we installed about 170 tracking tunnels in the West Matukituki valley to establish what predators were about that have been compromising bird breeding numbers. Answer: too many opossum and mice.

And on another front the means to scientifically establish how much seed the resident silver, red and mountain beech forest produced every three months. Answer: lots!

So-much-so, on both counts that the valley became “eligible” if you like for the Dept. of Conservation, partners with the Trust, to schedule a 1080 poison operation. This was carried out about 2 years ago. Interestingly I literally lived in the midst of it I

Knowing it’d be successful like in other areas like the Routeburn in “buying time” for more native birds chicks to reach maturity, work began in earnest on installing what now amounts to about 620 traps or various types in the valley [mostly high quality DOC 250’s], so that as the predator numbers inevitably increased, we’d be ready with other means to make sure the balance of bird v. vermin, swung in favour of the former.

A welcome increase in native bird populations in Mt Aspiring National Park

It was back in 2013 that I was introduced to the Matukituki Trust, the brain child of Gillian and Derek Crombie. They’d been climbing annually in Mt Aspiring National Park for many years and had become increasingly disturbed by the diminishing bird life in the West branch of the Matukituki river valley [which hosts the New Zealand Alpine Club’s Aspiring Hut], so they approached the local office of the Dept of Conservation [DOC] and in no time at all formed a partnership with them.

Initially rather than immediately focusing on trapping and getting predator numbers down the Trust adopted DOC’s methodology, which in essence is all about science, and a programme was planned to establish which predators were present, quantifying their food source, and from this planning a strategy, which as it turned out involved the use of the very efficient 1080 poison, followed by an intense trapping programme, which by now equates to 600 traps in the valley.

Now three years on the evidence of our labours is easily evident in the form of a significant increase in various native bird species, thus giving us deep satisfaction and justification of what is by now 1000’s of hours of hard labour, more-often-than-not volunteer based.

Beech Seed gathering for counting re beech mastDOC staff, a Trust director and volunteers installing funnels which catch beech tree seeds, a significant component of predator diets.

This means of quantifying food, was also augmented by the shooting down of branches of the trees so prescriptive amounts of leaves could be examined and seed counts done. The data then being uploaded to DOC’s database system, and weighed up in relation to other areas, so resources could be utilised efficiently. Photo credit Southern Light

Kakariki courtesy doc
This 2016 year the yellowed crowned parakeet the kakariki has returned to valley in the form of a population observed so far [scientifically] to be numbering 20 birds for sure, and maybe totaling at least 40. Photo credit DOC
Kakariki feathers
Three years ago the only evidence we gathered as to the presence of kakariki was a dead bird we found near Aspiring Hut. Photo credit Southern Light
Tom tit
The local population of the tom tit, an indicator species, has grown significantly over previous years. Like wise blackbirds and thrushes, which are competitors, but its better to see them rather than nothing! Photo credit Southern Light
Black back gull chicks
Many black back gull chicks are now fledging in the Cascade Stream bed near Aspiring Hut. Again first time for many years this has been seen. Photo credit Southern Light

Kea behind beech treeKea numbers are notoriously hard to know, but in the last two years juvenile numbers have been high from Dec on-wards. A mob of 32 were observed trying to dismantle a Robbie 44 helicopter, just several weeks after 1080 was spread, and this stroke of luck confirmed a long held belief that the valley is a nursery, as they were all juveniles.

This bird and a known banded companion were playing hide’n seek with me a week ago. Photo credit Southern Light

south island robin
The beloved south island robin [another indicator of-good-things-bird-wise, species] are now literally everywhere – up until a few months ago it was my job to observe and count, and now it’s pointless as most are not banded for easy identification. Photo credit Southern Light
The remainder of the photos below [Photo credits Southern Light] are shots taken while gathering data early on in the programme. Tasks like tracking tunnel installation – about 170 of, and thats mice footprints you can see [other high in number predators were ‘possums’

Frost

River crossing

Carrying tracking tunnels

Mice prints

Dead possumPesky ‘possum numbers are now so reduced that the bush is significantly improving in health and “looks”.

On closing some may ask why trapping them for fur/money is not carried out instead of using 1080. Well the answer is simple: as numbers reduce it’s not possible to continue economically, so the trappers bail thus the smaller population grows again very quickly.

 

In NZ, as opposed to their native Australia, they only need to spend 10 percent of their time eating, and 90 breeding. In Aust. it is the other way round. And of course they then grow larger here


Further reading of interest socially and otherwise:

1080 and science denial: an Our Changing World summit | Our Changing World | Radio New Zealand

We all know the saying: ‘nature abhors a vacuum’. Science denial, though, seems to love an information vacuum and thrives in the absence of fact. Environment and science writer Dave Hansford saw what he thought was an information vacuum around the use of the controversial toxin 1080 to protect New Zealand’s native wildlife, and it motivated him to research and write a book: Protecting Paradise – 1080 and the fight to save New Zealand’s wildlife.

“I think somebody had to [write a book like this],” says Hansford. “There have been a great many books opposing

Source: 1080 and science denial: an Our Changing World summit | Our Changing World | Radio New Zealand

photo credit Radio NZ