Wader population trends at Tahuna Torea

While researching my latest nature report to the Tahuna Torea Residents and Rangers I found some great bird counts in the reserve made in the 1980’s that had been entered on eBird. Unfortunately an oversight in the design of the website means you need to know a statistical programming language to extract population trend data for a location (however if you are able to stumble across an old checklist you can download the data). At the meeting Chris Barfoot supplied me with a brilliant 1993 report on the reserve which had a new set of data recorded by Micheal Taylor.

This new data adds valuable insight into the decline of waders in the Tamaki Estuary which the Tamaki Estuary Environmental Forum has recently published an article on. I have compiled the data and plotted it for key species below.

UPDATE 23 JUNE 2021. Here is an interesting snippet of history complied by the Howick & Pakuranga Times “Kuaka [bar tailed godwits] and red knots gather on the Cockle Bay estuary in thousands before flying to Korea and on to Alaska to breed each March, to return in September. In February-March they swoop over Point View ridges where farmers used shotguns before the birds were protected in 1941. They were plucked and preserved in their fat in ceramic jars.” Source: https://www.birdingnz.net/forum/viewtopic.php?f=3&t=11024

UPDATE August 2021. More data found in old journals. Graphs updated and presented to the Ōrākei Local Board.

Feeding our forests

I have begun doing some work with the Northern New Zealand Seabird Trust who invited me to come and help them with some field work on the Poor Knights Islands. My father had visited the Islands when he worked for DOC in the 1990’s, his stories about the reptile abundance really inspired me to do restoration work, and I jumped at the opportunity to go.

Landing on the Island is notoriously difficult and our first shot at it was delayed, we had to go back to Auckland to wait for better weather. The islands are surrounded by steep cliffs that made European habitation impractical, Māori left the area in the 1820’s. This means the island I visited has never had introduced mammals, not even kiore! I spent days cleaning my gear to get through the biosecurity requirements which are incredibly strict for good reason.

I have explored a few predator free islands including Hauturu / Little Barrier Island which has been described as New Zealand’s most intact ecosystem. However it was only cleared of rats in 2004. When I am photographing invertebrates at night in mainland sanctuaries or forests with predator control (like Tāwharanui Regional Park or parts of the Waitakere Ranges) I see one reptile every eight hours or so. On Hauturu / Little Barrier Island I see them every 20 minutes, but on the Poor Knights it was every two minutes! Bushbird numbers were lower than other islands, I expect this is because reptiles and birds compete over prey species. I wonder if reptile numbers on other islands might be slower to recover because they are preyed on by bushbirds. I reckon that the Poor Knights total reptile and bushbird biomass is much greater than the restored islands I have visited. One reason for this is that reptiles use less energy to hunt than bushbirds but the other reason might be because it has more seabirds.

While walking through the bush at night I would sometimes hear a crashing in the canopy followed by a soft thump on the ground. In an incredible navigational feat the seabirds somehow land only meters from their burrows. At night I heard Buller’s shearwater, grey-faced petrel, little penguins and diving petrel (fairy prion finish breeding in February). While monitoring birds at night I was showered with dirt by a Buller’s shearwater who was digging out a burrow. In my short time on the island I saw cave weta and three species of reptile using the burrows. Like a rock forest the burrows add another layer of habitat to the ecosystem. It was incredibly touching to see the care and compassion the researchers had for some of the chicks who were starving while waiting for their parents who often have to travel hundreds of kilometres to find enough food. The chicks who don’t make it die in their burrows and are eaten by many invertebrates, the invertebrates in turn become reptile or bushbird food. The soil on the island looked thick and rich, when it rains nutrients are bought down into the small but famous marine reserve which is teaming with life.

I was only on the island for three nights but I was very fortunate to experience a pristine ridge to reef ecosystem. Seabirds are incredible ecosystem engineers who were an integral part of New Zealand’s inland forests for millions of years. Communities are making small efforts to bring seabirds back to predator free island and mainland sites with no control over seabird food sources. If we really want intact ecosystems we will have to make sure our oceans have enough food for seabirds to feed our forests.

Fairy tern models used as stand in parents

New Zealand Fairy Tern at Auckland Zoo

In December 2020 I jumped at the chance to help the Department of Conservation and Auckland Zoo with New Zealand’s most endangered bird. I provided 3D printed fairy tern models (that were designed for use as decoys) to Zoo staff who hand reared a chick through to fledging. A soft yellow tape was wrapped around the models beaks to make sure the valuable chick did not injure itself. The models stayed with the chick to its aviary bach until it learnt to fly and feed for itself.

Tubeworms are awesome!

Tubeworm mound

I was pleased to read about Dr Mark Morrison’s 2020 discovery of tubeworms colonies in the Hauraki Gulf. The Marine Park has been heavily impacted by bottom impact fishing and epi-benthic biogenic habitat is now hard to find. I wanted to see what the tubeworm colonies looked like and how the wildlife differed from degraded seafloor.

I was therefore very excited to be invited on an expedition to inspect some tubeworm mounds discovered by Shane Kelly and Carina Sim-Smith near Moturua Island. They were relatively deep at about 25 meters whereas Mark Morrison’s ones were in the 12-22 meter range. The conditions were perfect with no wind and clear skies. We descended very quickly into the dark as we knew at that depth we would only have about half an hour to explore the area.

Scarlet tubeworm colony (Galeolaria hystrix)

I was stunned at the size of the mounds, they rose up to nearly a meter from the seafloor (much taller than any shellfish bed) and reminded me of coral reefs. Tubeworms grow in a similar way to coral, layering their calcareous skeleton homes upon each other as they filter feed and grow upwards. And just like some corals when I got about half a meter away from the tubeworms they retracted their red tentacles in a Mexican wave across the mound, it was really beautiful and I should have made a video of it.

The diversity was incredible, I was amazed at the amount of filter feeding colonial epifauna growing on the mounds. I wondered if the sponges, ascidians, anemones (which are also filter feeders) were competing with the tubeworms or if the relationships were commensal.

Conger eel

I don’t know the surrounding area but I was surprised to see so many fish including a young sandagers wrasse. This conger eel living in the mounds was a real highlight and I wish I had gotten a better photo. Goatfish were the most abundant fish species.

While the scientists collected a few specimens for identification I took two minutes to record a video which I later converted into an orthomoasic map using this technique (which I am still polishing). The map revealed an interesting pattern similar to that made by restored mussels as they clump together over time. It would be good to validate it by mapping more filter feeding structures.

The fragile mounds are easily damaged by dredges and trawlers, it’s likely that fear of catching gear on anchors from the adjacent mussel farm has protected the beds. The experience has me wondering what a huge protected tubeworm colony might look like, and how can we make more of these incredible structures.

UPDATE: July 2021. I was able to check our Dr Morrisons ones. Video from GoPro attached to my camera here.

eDNA

I have spent a fair bit of time thinking about how citizen scientists can measure the health of their local streams using Macroinvertebrate Community Index (WIMP & SHMAK) and the index of biotic integrity (IBI) for New Zealand fish. The great thing about using stream life to measure stream health is that the animals act as 24/7 sensors that measure any of the countless pollutants that harm life. The problem with it is that finding and more importantly identifying species involves disrupting them.

eDNA (environmental DNA) sampling solves this by measuring the presence of stream life base on the tiny fragments all life constantly erode into water. Wilderlab have set up a testing system with relatively cheap kits available for citizen scientists. I found it easy to use on my local stream (which is very degraded). I am really excited about this technology, especially as the price comes down and results are benchmarked against existing stream health Indices.

Artificial shag roost

This artificial shag roost in Hobson Bay was constructed by Auckland Council to mitigate the effects of a boardwalk being constructed next to an existing shag roost. Nesting materials and a plywood decoy has been added but the birds are yet to show interest in it.

Stream Health Monitoring guides

As communities get increasingly worried about the declining quality of their waterways there is more interest stream health assessments. I am a huge fan of the Waicare Invertebrate Monitoring Protocol (WIMP) which is simple enough that school students can use it. However the Waicare programme has been largely defunded by Auckland Council and there is no way for the public to share WIMP data. NIWA and Federated Farmers of New Zealand have put together https://nzwatercitizens.co.nz/ based on the New Zealand Stream Health Monitoring and Assessment Kit (SHMAK). It is great but incredibly hard to use, the manual is horrific. I believe this is being addressed but will take years. To help, the science learning hub has made this great guide for teachers and students. NIWA have put together some videos. They are not published together anywhere online so I have posted the list below:

Alternative words for environmental terms

I really like this list of alternative words for environmental terms, offered by George Monbiot & Ralph Steadman. I have rebuilt it in HTML with some additions and deletions, I plan to evolve it over time.

Existing termsWhat’s wrong with itAlternative terms
EnvironmentCold, technical
Seen as seperate
The natural world
Global warmingWarm sounds pleasantGlobal overheating
BiodiversityInaccessibleWildlife
Ecosystem servicesAnthropocentric and reductiveLife support systems
Nature reserve‘reserve’ suggests coldnessWildlife refuge
Habitat destruction
Deforestation
Biodiversity loss
Sounds like they are happening to themselvesEcocide
ConservationPreserving what little is left rather than rebuilding living systems (New Zealand needs a department of Restoration)Restoration
Clean rivers / seasSounds too hygienic, is blind to waters as habitatsThriving rivers / seas
Fossil fuelsSuggests redundancyDirty fuels
Sustainable developmentGreen growth is an oxymoronRegenerative development
PhotopollutionToo technical, doesn’t indicate what is being impactedEcological light pollution
StormwaterSuggests that the water is unwanted, unnecessary or unsavouryRainwater
MARINE
Fish stocksSuggests fish are here to serve usWild fish populations
Biofoul, foul, foul groundSuggests there is something ugly about biogenic habitatsSea life, seafloor life, benthic epifauna
FishingCasual everyday activityKilling native wildlife
Bait fishImplies the fish exist to be baitSmall schooling fish / forage fish / small pelagic fish / shoaling fish
Bait ballImplies the fish exist to be baitTight ball of fish
SeaweedsPest connotationsOcean plants
Mobile bottom contact fishingImplies a light touch(Mobile) Bottom impact fishing