Mangaiti’s very own Jurassic Park

The pine trees in the north end of Mangaiti Gully behind Rototuna Primary School have several pairs of white-faced herons nesting in them every season. Watching the activity of these three looked and sounded very prehistoric. Double click on the video to enlarge picture. This video was taken on an old iPhone. It would have be so much better if taken with a good video camera/phone with a zoom lens.

A duck nest in July

Our weeding team came across this mallard (or a hybrid variant) duck nest of fourteen eggs. Birds that have the most breeding success in a predator environment have evolved to have either large clutches or nest several times in a season or both. This ensures they maintain or increase their population. Because our New Zealand indigenous species did not evolve with predators, or very low predation, their nesting frequency and number of eggs per clutch tends to be smaller. This, with other environmental pressures, all to often puts our indigenous species into the “at - risk / declining” in the DoC category. The biggest threat to this duck brood would be hedgehogs, pukeko and domestic cats.

Moving into another restoration area – The Pines

This season we have been opening up another space to add to our restoration area. Called “The Pines” it is the area behind Rototuna Primary School where there are very old large pine trees. General access is from the end of Cabernet Close. Service tracks are being built (photo, before and after), and early plantings have been done by the cubs and scouts on the easier to access parts. Ultimately, we are aiming to create a tawa forest under the pines. We have over 100 seedlings being raised in pots for this. Tawa are frost tender at their early stage of growth so the pines should offer them frost protection, and being tall and old the pines will allow plenty of light through to ensure good growth of the young tawa. The pine trees can be seen in the top back ground of the photos

Eel platform over popular

The Mangaiti eel feeding platform was listed on several Facebook pages over the school holidays as a free activity to do with kids. Unfortunately, this overwhelmed the facility. The eels could not eat all the food that was being offered, which resulted in large quantities of food littering the stream bed. Our Trust volunteers had to remove the surplus food using a net. One of these extractions resulted in removing 2.7Kgs. If you are at the platform and there is food littering the stream bed, please do not add to it. Our security camera, put up to protect the eels, had so much activity that the solar panel could not keep the battery fully charged, which meant the panel had to be upgraded from 3.2W to a 6W.

Community engagement

One of our Trust’s objectives is to have community engagement. In this past year we have had Sam the Trap Man “walk and talk” which was organised by HCC. Sam is so knowledgeable and a great storyteller. He can make little things so interesting. We hosted the Green Pavlova conference field day. This conference was attended by a number of council employees from around New Zealand. They showed a lot on interest in how our Trust worked and were particularly impressed with our achievements. National Tree Cropper Association’s conference also had a gully visit to Mangaiti as one of their field day options. There was an impressive amount of interest considering our restoration project was a bit outside their sphere of interest. The Kids in Nature programme run by HCC had numerous school class visits to see the eels. Three students from Rototuna High School chose our trust for their community project this year and have been attending our Wednesday working bees each week. We hosted the scouts and cubs (Photo)with a planting each this season. It was fortunate that this season we had suitable planting areas for this type of group planting. It was done between 6.30 and 8pm in the evening. We put up a temporary light and most had head lamps. They were all so enthusiastic.

Growing epiphytes for your restoration area

Astelia epiphytes are not only spectacular to view in the New Zealand bush canopy, they should also be considered for any restoration project. At some point restorers must move past planting pioneers and think about the more complex flora that makes up our bush ecosystem. Astelia epiphytes are one of these. We grew ours from small pieces gathered from fallen epiphytes when bush walking. We had no rule book to follow so approached this in two ways. First, as we are fortunate to have a shade house, we used a short piece of punga trunk, took a wedge out of the side, inserted the epiphyte root into the wedge and wrapped it in sphagnum moss to hold moisture.(Photo 1)These were then hung up on the wall of the shade house.

 2015 - Photo 1

With regular watering from the sprinkler system, they grew into mature epiphytes over the following eleven years.(Photo 2)

 2026 - Photo 2

We then employed an arborist to install them into a variety of trees in our 10-hectare restoration site.(Photo 3)

Arborist installing epiphyte -Photo 3

The second way was to basically do the same as with the punga log but install the epiphyte cutting directly into the bush site to take its chances with the weather (Photo 4).If you are doing this, select a site of semi-shade and / or facing south so as not to get the full blast of the summer sun. This worked well. While not growing as much as the ones in the shade house it has grown to a healthy size in the fourteen years that it’s been installed (photo 5). This is probably a more practical option for most restoration groups.

2012 - Photo 4

2022 - Photo 5

We used two Astelia species: Astelia solandri and Astelia hastata / Collospermum hastatum with some of the Earina orchid species coming along for the ride. These orchids grow epiphytically as well and are often found among fallen Astelia nests. This all adds to your restoration mix.

Fifteen years of restoration

To celebrate fifteen years of restoration by volunteers in Mangaiti Gully we produced a photo book for all our past and present volunteers. It is hard to imagine what our section of the gully looked like back in 2010. There were no tracks, with honeysuckle, blackberry and grey willow dominating the wet gully floor. Clearing and planting was done section by section. First build a track to gain access, then drill and poison the willows followed by clearing the honeysuckle and blackberry predominately by hand. There was minimal spray used back then. As the tracks were built, they were gradually connected. The public then started to use them at which stage they were upgraded to what they are today. A highly successful public asset for our city.

Juvenile weta

We have been collecting bamboo stakes from the field that are no longer necessary to hold up previous plantings. These will be repainted with coloured tips and reused next planting season. They were being stored in a garage. In the evening when the garage was being inspected to secure it for the night little weta were noticed emerging from some of the bamboo stakes. Seven in total were collected and returned to the gully to carry on their lives. The photo of a weta sitting on a finger shows how small these juvenile weta are. It is interesting to see how long the antennas are. They are out of all proportion to the size of their small bodies.

A snail collection!

See photo. This was taken when servicing one of our rat bait lines. A thrush (or maybe a blackbird) is using the block of wood as a convenient bashing post to break the snail shells to get to the succulent snail inside.

Annual spring tracking tunnel monitoring

We monitor rats across the full 30 hectares of Mangaiti Gully in the spring and autumn to see if our control programme is doing what it is supposed to. Rats are known to be smart. This can lead to rats learning how a programme works and, over time, start to avoid some traps or toxins leading to an increase in the rat population. This is why regular monitoring is important. Thankfully there is no sign of this happening at present. There was only one rat recorded down by Wairere Dive, Hukanui Road end this spring.

Wineberries are a great pioneer species

Wineberry (Aristotelia serrata) is showing clusters of pink flowers in the gully this spring. Wineberry is a good food source for our birds offering them nectar, fruit and seeds. It is a great tree to plant at the very early (pioneer) stage of any restoration planting. They grow large enough to shade out pesky weeds. They seed at an early stage in their life. With the help of bird dispersal, it creates natural seedlings throughout a restoration area.

Black mud fish

In December 2023 our Trust submitted an application to the Department of Conservation (DOC) for the translocation of black mudfish into a blind gully swamp in Mangaiti, Hamilton, New Zealand. This was after identifying the location as an ideal natural mudfish habitat and it being highly probable that mudfish would have occupied this location in the past, before European settler land modification. This is also in line with our Trust’s vision: To manage the gully in such a way that native fauna (birds, fish, bats, reptiles & insects) will re-establish, either naturally or by introduction and for this to be sustainable. In March 2025 this year, a permit was granted. Translocating mudfish has historically, not been that successful so there was reluctance by DOC to translocate them from a known stable habitat. However, the Rotokauri urban subdivision is about to commence where 14 sites of mudfish have been identified. These wetland sites, which in most cases are farm drains, will be modified (drained) during the groundwork. Because our permit specifies that they are to be translocated from “at risk” habitats within Hamilton City, this has, in essence, become a rescue mission of an at-risk, declining, indigenous species through habitat loss. Managing the translocation is not that straight forward, and part of the DOC permit requires three years of monitoring and reporting. We are fortunate to have a retired NIWA marine scientist as one of our volunteers who is being the lead on this project. The following Link https://www.doc.govt.nz/nature/native-animals/freshwater-fish/mudfish/black-mudfish/ will take you to a DOC pdf with extra links explaining all about the unique features of this species. Photo: Waikato Regional Council

Translocating eels

A concern had been raised that successful establishment of mudfish might not succeed if there was heavy predation by eels. Mudfish have evolved alongside both of our long and shortfin eel species. While the eel population in the main Mangaiti stream is quite healthy, from eDNA testing we suspected that the eel population in the swamp we have identified for the mudfish release was low. We have therefore undertaken a fish survey using Fyke netting at 5 sites along the length of the mudfish release area (site Fyke 1-5, Figure 1). After setting the net 6 times (site 2 was sampled twice) the only fish caught were 4 short fin eels (ranging in size from 700 - 813 mm) and 4 very healthy banded kōkopu (145 - 180 mm long). The kōkopu were all released where they were caught, and the eels were transferred into the upstream tributary of the main Kirikiriroa Stream where there was suitable eel habitat.

Book review – KIWI BEES HAVE TINY KNEES Native bees of Aotearoa New Zealand

In the January 2025 blog posting there was an article on NZ native bees. This book is an excellent follow up on that. Although it is designed for young people it is packed full of interesting information that most adults would not know. There are a number of QR codes throughout the book that take you to YouTube videos that support of the page content. The author, Rachel Weston, needs to be congratulated for bringing these tiny native insects to our attention. Every school library should have a copy. It can be purchased online direct from author Racheal Weston’s website https://www.rachelweston.co.nz/shop/ for $30.

A story from a Mangaiti Gully neighbour

When we first moved here 15 years ago, there were no tūī. It took about 5 years of clearing, planting and predator control before we saw our first tūī in Mangaiti Gully. They are now so common we have regular visits to our bird bath, and they are so comfortable around us they let us this close to film them. Check out this video. (video – John Smulders)

Dog poo!

Since opening our section of the gully to the public we have had to manage a certain amount of anti-social behaviour. While this is always disappointing it was not unexpected. Anecdotally it would look as though youth was responsible for most of it with their graffiti, drug paraphernalia, pulling plants out, leaving rubbish behind and even lighting fires. However, one anti-social behaviour not attributed to youth, is the practise of SOME dog walkers disgusting habit of disposing of their dog’s poo bag into the gully understory as they walk along our tracks. If you own a dog, you also own their poo bag. Please do not dispose of it into a natural area. Dog poo in a plastic bag is not part of nature. Take it home. That’s part of the responsibility of owning a dog. If you could do that please, it would be great.

Wētā nook

With the success of the eel feeding platform and the sign educating the general public on the unique life history of the longfin eel and why they are special, we thought we could carry that theme to other species we have in the gully. With this in mind we have developed a tree wētā nook. We have built a short track into the understory and installed three wētā motels with the possibility of installing a fourth. From experience it often takes some time (up to a year) for wētā motels made out of new timber to populate. Two of these are new and one is an old mature one that’s been relocated to this nook. The plan is that when the wētā motels are populated we will design a sign showing the life cycle of the wētā and, because of its relationship with the Pūriri moth include the moth’s life cycle as well. The nook is off the red track going north from the depot and just past the seat. See video. The video size had to be reduce to load on this site. This have reduced the quality some what.

Staff (stream water) gauge

As a public interest project we have installed a staff gauge in the stream that can be seen from the walk bridge that runs between Grenache Place and St James Drive. The gauge itself was donated by Waikato Regional Council, being second hand and surplus to their requirements. The sign on the bridge railing explains how to read the gauge. Zero is at the February summer drought level. We will be putting coloured tape on the gauge indicating the highest stream level during a rain event. We have just had (6th April 2025) 25mm of rain over six hours which raised the stream level at the gauge to 75cm (750mm). See photo.

Red and Yellow admiral breeding programme update

The red admiral breed and release programme is proving challenging and demonstrates that to translocate species you sometimes have to be prepared to be flexible and persistent in your approach. Breeding within the tunnel house is proving elusive. There is ongoing planting of flower species for a nectar source which, once established may encourage breeding. Trips to Awakino Gorge (south of Piopio) with nettle plants in pots, with the objective of getting red admiral eggs to bring back to the tunnel house, did not prove successful this year, with no sign of butterflies at the site. Fifteen yellow admiral caterpillars were relocated from nettle outside the tunnel house to inside so as to finish their life cycle protected from parasitic wasps, only to find that 10 were eaten by a rogue praying mantis that must have come in on a nettle plant. That left only five to release. We have decided that, rather than plant a nettle plant here and there, it would be better to plant a decent size grove. The theory is that when we release butterflies, they have a better chance of finding the nettle and, once they start laying eggs, the caterpillar’s life cycle has better natural protection among a grove than a single plant. Ongaonga is a hard plant to grow. If the growing conditions are not to their liking, the plants do not hesitate to die. We have selected what we think is an ideal spot. It is shaded from direct sunlight being under established manuka, never dries out but is not boggy and is easy to protect from the public. Seedlings for this planting is underway, see photo.

Evening moth pollinators

As the autumn draws in, we are losing some of our interesting moths. During the summer if you are wandering around your garden at dusk, you will probably see a moth hovering over flowers like hummingbirds of the insect world using an enormous amount of energy while gathering nectar. The moth in this video is probably a Helicoverpa armigera or maybe Chrysodeixis eriosoma. These moths are some of the many invertebrates that go about pollinating our flowers. The caterpillar stage of the Helicoverpa armigera can be a bit annoying by eating its way into tomatoes, usually around the stalk.