Thursday, April 11, 2019

Tui well established in Mangaiti Gully

Parent feeding a young Tui. Mangaiti Gully.
 Photo by Owen Cole

We have spent a lot of time down in the gully over the last eight years. Over this time we get a very good feeling on what the fauna is up to. There has always been some winter sighting of Tui but gradually an odd one was seen during the spring / summer months. Then, in the spring of 2017, a sighting of a juvenile Tui up the Gordonton Road end was reported and one was thought to have been seen around our depot off Coleraine Drive.
The winter of 2018 saw a spike in Tui numbers. In August twelve were seen gathering among the bare branches of a black locust tree late one afternoon.  A couple of weeks later at least 18 (it was hard to count exactly) were seen feeding in the Taiwanese cherry trees in Sovereign Isles. As spring approached and Tui paired up and created territories, many remained in the gully. Sightings were now common.
In December 2018 juvenile Tui was either seen and / or heard in three locations: in the gully just off Wairere Drive; at the stream junction where the stream leads up to Gordonton Road and up the Sexton Road end. For every one seen, we are confident that there are many others. Tui are well and truly established as a thriving part of the Mangaiti Gully fauna.
We believe this is the result of the Halo programme that was responsible for getting Tui back into Hamilton.  Then in Mangaiti Gully this was followed by a rat eradication programme and possum control which has enabled the Tui that came to successfully breed.
This has taken a number of years to get to where we are now and has  involved the help and support of a lot of volunteers, for which the Mangaiti Gully Restoration Trust are truly grateful.  This has enabled our trust to work successfully towards achieving our vision which is, “to restore the native flora of Mangaiti gully back to, as near as is practical, pre European status and 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.”

Introducing tracking tunnels to monitor rat activity in Mangaiti Gully

Tracking tunnel locations in part of Mangaiti Gully.  

Is to develop a snap shot of the rat activity in the autumn (high activity period) and spring (low activity period) each year over a number of years to assist us to manage our rat eradication programme more effectively. It will also be used as a base line if, at some point in the future, we make changes to our present eradication programme.
Tracking tunnels are a standard method of monitoring recognised by institutions involved in environmental practices in New Zealand.  The target is to have the tunnels at 50 metre intervals along the gully floor for the entire 30 hectares of Mangaiti Gully. The tunnels remain in place. At the time of monitoring, peanut butter is smeared on the wall half way along inside the tunnel. A white card with a black ink pad in the centre is inserted. This is left over night and removed the next day.  If a rat, or any other animal (mice or hedgehog) or insect (weta) enters the tunnel and walks over the ink pad then their foot prints are left on the white card. Each tunnel is coded and GPS plotted on a map.

White faced heron nesting

Chick perching by the trunk in Mangaiti Gully.
Best picture available taken with an I-phone. 

In the pine trees at the back of Sexton Road (the northern end of Mangaiti Gully) a pair of White Faced Herons had a nest this summer raising two chicks to fledge. The young were seen on the 5th of February fumbling around up in the canopy flapping from branch to branch as they tested their wings all the while demanding a feed from their parents.
While many people probably think that the white-faced heron is indigenous to New Zealand, it is actually found throughout most of Australasia. It is a recent arrival being self-introduced (which classifies it as native) to New Zealand in the late 1940s.
Breeding generally takes place in the spring in New Zealand. Both sexes share the task of building the nest, incubating the eggs and caring for the young. The nest is an untidy shallow bowl, made of sticks and usually placed on a leafy branch 5–12 m high. A typical clutch has three to five pale blue eggs. Normally only one brood is raised per year. Incubation lasts approximately 25 days. The parents guard the chicks for 3–4 weeks and fledging takes place 40 days after hatching. Typical nestling predators in New Zealand include Australian magpies and harrier hawks. (Wikipedia)

Building a Morepork / Ruru – nesting box

Morepork nest box and owl on tree fern in Mangaiti Gully.
Photo by Jeanette Holborow

If you live on a gully, or have a bush area close by, you might like to think about installing a Morepork / Ruru nest box. Check out this link for a design: . Getting it up a tree might be a bit of a mission for many of us so you may need to get help for this. You could always get an arborist to install it but, unless you have one as a friend, it would have a cost attached to it.
Rats and possums could be a problem so it would be advisable to have tin sheeting around the tree trunk above (if the branches above touch other trees) and below the nest box. 

Sunday, December 2, 2018

DOC’s latest fresh water fish survey.

Electric stun fishing does not kill the fish. 

The Department of Conservation’s new threat classification report for fresh water fish 2017 was released in August this year. There are three species that are found in the Mangaiti Stream system that have the “At risk – declining” status; giant kokopu, longfin eel and inanga, .
The giant kokopu (Galaxias argenteus) inhabits the ponding area in the gully below Sexton Road and has been found in the main stream. These tend to be active at night so are rarely seen. It was when Waikato Regional Council’s scientists were doing a fish survey using the electrical stunning method that they were located. Only one giant kokopu was recorded in the stream.
The Longfin eel (Anguilla dieffenbachia) has been mentioned several times on this website. The report noted that the decline in water quality in many areas has resulted in the shortfin eel (which has a “not threatened” status) occupying habitat that formerly held the longfin eel which suggests that the two species may be competing within a habitat or it could be that the longfin eel prefers better water quality. Either way it is clearly evident that the shortfin eel is the dominant species in the Mangaiti waterways. In the 2012 survey there were 2 longfin eel and 21 shortfin eel counted in a fifty metre length of stream. The longfin eel has a very long life and the ones we are seeing appear to be mature adults. The worry is that the population is not being maintained with juveniles moving upstream in their normal life cycle. 
In the 2012 survey, 29 inanga (Galaxias maculatus) were recorded. 
Planting the stream edge becomes all the more important when you are aware of the status of some of the occupants.

Book review

Rat Island: Predators in paradise and the world’s greatest wildlife rescue
By William Stolzenburg
Bloomsbury: 2011
ISBN 978 1 4088 2511 2
William Stolzenburg is an American journalist who writes a lot about animals, but for the past decade, his focus has settled on that particular class of creature called predators. Rat Island is one of three that he has recently published. The other two are: Where the Wild Things Were and Heart of a Lion.
Rat Island focuses on three main island groups; the Aleutians in the Bering Sea, (the group that run south west from Alaska), Clipperton Island which lies one thousand three hundred kilometres off the coast of Mexico and the New Zealand group.
He covers each group with a detailed back history that sets the scene for the full-on attack to eradicate the introduced predators. This is followed up with a description of the recovery of the particular ecosystem or indigenous species that was being targeted.
A large part of the book is focused on New Zealand. The work attempted in Fiordland in the 1880’s by Richard Henry, an early pioneer in pest management, and in the 1960s when Don Merton became actively involved as a junior in the Wild Life Service, all set the scene for the battle to recover Islands that were being decimated by pests. One of the big breakthroughs was the discovery of the single feed bait Brodifacom for the eradication of rats, which are the major pest and the most difficult to eradicate. This replaced warfarin that required high doses delivered over several feeds.
The work done in New Zealand influenced how island sanctuaries around the world managed their eradication programmes. Not all went smoothly. Each island had their unique features that had to be taken into account. There were cases of unexpected collateral damage to manage. Bureaucrats caused frustration then, as they do now. Islands close to urban areas had ill-informed protesters to deal with, but despite this, all had a successful ecological outcome.
The early chapters on the history of the ecological effect of human occupation on Aotearoa, which started seven centuries ago, should I feel, be included in the New Zealand high school history curriculum. We should all understand the ecological damage we have done in the past so that we can better manage the future.

This book is very well written and a really good read. Does it give you hope? I am not sure. Read it and see what you think. 

Willow (and Poplar) tree felling in gully

The finishing touches of felling a poplar

The removal of the grey willows from the gully in our restoration area has been a long process. The project was started because of the arrival of the Australian willow aphid in the Waikato a couple of years back. The aphid’s excretion (dew) causes a black mould that completely covers the understorey plants. Coinciding with the aphid’s arrival we experienced a massive population explosion of the German wasps that summer. These wasps feed off the dew from the aphids so the abundance of food may well have been responsible for this population increase. 
We have had a willow poisoning programme running for a couple of years now and this is ongoing.  We were getting concerned that the dead willows along the tracks were falling down and were becoming a safety concern so we applied for, and obtaining funding from Hamilton City Council Community Funding Grant to employ a contractor to fell the trees of concern. This funding has not finished the job so we have obtained further funding from Len Reynolds Trust to finish it off.