Hauturu kiwi monitoring trip

Cave weta, Pachyrhamma

I was recently lucky enough to monitor kiwi on Hauturu with the Little Barrier Island Supporters Trust. I have done this many times before at Tāwharanui with TOSSI. The exercise involves a good hike to the destination at night then sitting quietly in the dark listening to the sounds of the forest for a couple of hours. I have met some great people doing this and this trip was no exception. They patiently waited for me as I inched along the tracks on the way back to the hut, inspecting every tree for hidden treasures and some even came out with me again on their free nights. I have posted all my invertebrate observations here on iNaturalist where the community is helping me identify them all. I have also posted some fungi which were a hot topic among the volunteers.

It’s an incredible island where one can get a sense for pre-human New Zealand. Here is a list of some observations I made over the 12 days I was there.

  • I saw less invertebrates, birds and geckos at elevation.
  • Piwakawaka following Tieke on two occasions.
  • By weight there was much more industrial plastic pollution (mussel floats) than domestic plastic pollution on the beaches.
  • Similar gecko numbers in winter compared to summer. One seen every 20 minutes on night walks.
  • Cave Weta were the dominant weta by a factor of 10 or more. Tree Weta, Ground weta and Wētāpunga active.
  • Winter invertebrate abundance similar to mainland sites with predator control (and less birds). At night, in two out of three tress invertebrates were easily found.
  • Invertebrates not much bigger than raindrops stay hidden during the rain.
  • NZ Giant Centipede found 3m above ground inside a Kanuka tree that fell in the middle of the day. The species is very arboreal.
  • Korimoko chasing Ruru during the day.
  • Flock of 18 Kereru feeding on Muehlenbeckia.
  • A high of 12 Shore Skinks seen from one observation point. No other skinks observed.
  • Invertebrate diversity high with many species I had not seen before. Some had not been previously photographed in the wild.
  • Strange absence of Katydid calls.
  • Very empty streams with only Shortfinned Eel and Banded Kokopu observed. Huge flushing events the likely cause of low freshwater diversity and abundance.

Training iNaturalist

The artificial intelligence that reads photos on iNaturalist and identifies species is incredible. It often makes me double check an ID and has helped on many occasions. However I was pleased to see it bested by this stick insect I photographed who completely out-witted it 😀

Pest monitoring Selwyn Bush 2019

We identified 19 tracking locations (S1-S19) in 2014. The first 10 (S1-S10) were used in this survey. The survey was repeated in March 2019. The first 10 locations were searched and three out of 10 tracking tunnels were found. Seven new tracking tunnels were installed on the 10th of March. On the 16th of March another 9 tunnels were installed and all the tunnels were filled with an inked tracking card with peanut butter in the middle. Some locations were adjusted to make access easier. I noticed when trying to find the tunnels again with the Garmin InReach and App that the positions were often off by up to 16M. Thats a lot in the bush!

Locations of the 2014 tracking locations compared to the actual locations of the tunnels placed in 2019.

RESULTS

I find these mashed up prints very hard to identify, but here is my best guess:

S1 Hedgehog
S2 WW, Rat, Hedgehog
S3 Rat, Hedgehog
S4 Hedgehog, WW
S5 –
S6 –
S7 Hedgehog
S8 –
S9 –
S10 –
S11 –
S12 –
S13 –
S14 –
S15 –
S16 –
S17 –
S18 –
S19 –

WW = Winged weta, I was particularly looking for this species. See my blog post on tracking winged weta here.

Suspected winged weta tarsal pad print

I think we should probably ignore the tracking tunnels put out recently (S11-S19) as they may have been avoided due to (at at least some of) the target species being neophobic.

This would give us a result for 2019 of 20% Rat, 0% Mice, 50% Hedgehog. This indicates we have less rats & mice and more hedgehogs than 2019.

I have left the tunnels out there, it might be a good idea to retry in a few weeks. It’s interesting that we see more pests near the top of the bush, this has been observed before.

KMZ file with locations

My macro setup Jan 2019

Updated from 2017. I have upgraded to some second hand 600EX RT’s, a radio transmitter, 3rd flash and some custom designed and 3D printed soft boxes. Files uploaded here. The soft boxes are printed using transparent PLA which has a natural frosty finish and produces lovely diffuse shadows (0.2mm @ 5 layers). I painted them black & yellow and lined the mouth with black tape so as to not scratch the flashes. The 600EX-RT’s are quite heavy and I had to use epoxy glue to re-enforce the cold shoes. I fibreglassed a giant nail to the base of a Manfrotto monopod to create the portable outdoor light stand.

Example photo of a native wasp (Netelia ephippiata).

Red-billed gull decoys

I was recently asked to quickly create some red-billed gull decoys. I joked they might be better of using a decoy picnicker but the reality is this is another native species that is in real trouble (conservation status declining). I posed the decoys with their tails up but with legs so they could be used standing or sitting if they need extra anchorage.

Unfortunately these decoys were snapped off at the leg, we are not sure how, as it would involve a lot of force. So…

I made some more, these have been redesign to bolt on to a 1M long 8mm diameter threaded rod.
Here is what they look like installed. We dug holes in the ground and used a little cement to lock them into place. Fingers crossed they work.
Photo by Paul Kennedy
Photo by Tim Lovegrove.

Update October 2019: Win!
Note that the Northland Region Corrections Facility is making wooden Black-billed Gull nesting decoys, I don’t know how much they cost but they look cute!

A great article on the Wynyard gull colony project has been published here. Ohhhh and another article in the Guardian!

Tracking winged weta

I first noticed ‘winged weta’ in 2016 when I took this photo of a pterapotrechus moulting. They are particularly abundant in Selwyn Bush, Kohimarama where community groups are doing pest management and restoration. I wondered how many times introduced winged weta were being mis-recorded in tracking tunnels as our native weta. No foot prints have been recorded to compare so my son and I collected six (males and females, small range in sizes) in less than five minutes. We dropped them onto a board with footprint tracking ink, photo above.

Here are some closeups of the hind leg footprints.

The footprints look very distinctive to me so we probably don’t have to try and understand walking pattern (see ‘Footprint Identification of Weta and Other Insects‘). I think this must be because the tarsal pads are paired for winged weta and not in native weta. This will make identification of winged weta quite easy going forward.

Australian fairy tern decoys

After talking about my New Zealand fairy tern decoys I was approached by Australian conservationists about making decoys to attract Australian fairy tern. Although they are the same species they have brighter beaks and shorter eye patches so I modified the paint job a bit. The biggest difference between the sub-species seems to be that they flock together to nest. I imagine this will make the decoys more effective for this subspecies.

I lowered the design so it looks more like they are incubating, hopefully they will still turn into the wind ok. Photos below of the birds without spikes above and below.

PLA coated with two part epoxy resin then blasted with heat gun.

We’ve had some problems with these decoys, the black painted parts get so hot in Western Australia that the plastic melts leaving the decoys with flat hair cuts! The glass transition temperature for PLA is around 60° C. I tried covering some PLA with two part epoxy resin then warmed it up to try and simulate the issue. The epoxy worked well holding the form in shape even when I got it so hot the surface burned. However it did deform a little with bubbles and spilts, this might work as a patch up job but its not ideal, other ideas:

1. Changing the plumage to be less black (juvenile)
2. Printing with more infill (thicker heavier decoy)
3. Printing with another plastic
4. Creating moulds and using resins

I really like using PLA because it’s biodegradable and from a renewable resource but in this situation it just might not be up to the challenge. Common filament options are: ABS (won’t print with as good detail), PET (not glue-able) or Nylon (which has a lower glass temperature). I could print with plastic that has better thermal resistance like Polycarbonate, or print using dissolvable supports and no glue with something like PET but I would need a much more expensive printer. Unfortunately I think heat resistant decoys are going to be less environmentally friendly and either expensive or labour intensive 🙁

Update May 2019

Re-designed test decoys

I have made three new decoys to test, all are glued using two part epoxy.

  1. 40% infill and two coats of epoxy resin
  2. 20% infill and two coats of epoxy resin
  3. 40% infill

The numbers 1,2 & 3 are carved into the newly designed peg which is shorter but more heavy duty. The increased infill makes all of them heavier, this should help keep them down when the sand moves, if that does not work the painted legs should look more natural. The overall design of this decoy is a little more robust, it has it’s head ‘terned’ a little to help distinguish it from the other decoys I have made.

Update Dec 2019
These decoys were deployed from 3 Nov-20 December on Garden Island. They did not attract the target flock which nested elsewhere. With three of the days being in excess of 37 degrees the decoys got tested pretty well and show no signs of melting or splitting. They have been deployed in the researchers garden for further testing 😀

Photo by Claire Greenwell

Update April 2020

Decoy 2 developed a minor crack in the join, it was the weakest decoy with half as much infill for internal strength. No changes to the other two.

Pros vs Cons app

Pros vs Cons app

I am scoping a project I would like to build as a web app. To get an idea of how much work was involved in creating one I made a quick test app and published it here on the Apple App Store. Given my skill set the design work was a small part of the job (12%), CSS & JS was three times more (38%) and the rest of my time was spent on new stuff to do with getting the app to run on an iPhone (60%). I can probably halve that on my next project but it was a lot harder than I expected.

It’s a fun app, you can make lists like this 😀