Author: Barry Dent

Fifteen years ago I was very ignorant indeed about seabirds. When Sue and I helped with our first of I think 11 chick translocations, the first thing I learnt was that seabirds were not all just “seagulls’. Eventually I came to learn from the likes of Colin Miskelly and Helen Gummer that seabirds really are and ought to be pre-eminent in the New Zealand story.

New Zealand is still the centre for seabird endemism: 38 species breed nowhere else and 86 species breed here in total, out of 360 species worldwide. Populations-wise, however, they would once have been a much more dominant feature, before they were all but extirpated from the mainland by predators such as rats, stoats and pigs. Now we think of seabirds as perhaps belonging on rock stacks and little islands, despite a few happy mainland exceptions such as Hutton’s shearwater. I suppose this is yet another example of the shifting baseline idea expounded so well by George Monbiot in his book Feral: in our lifetimes we have thought of seabirds as breeding on islands, sometimes scarce; therefore it was always thus. In the recent past though, there would have been clouds of all sorts of seabirds, circling mainland high points, their nesting and burrowing and bringing food in from the sea and being eaten and dying and decomposing, having the biggest effect of anything on the ecology of the mainland.

We can see what it would once have been like by looking at their island strongholds today- vegetation modified by fertility changes, shrubs destabilised by burrowing, a profusion of life making use of their burrows and their leftovers. It’s no accident that there’s 300 mm of fertile topsoil across the formerly farmed piece of peneplain that is Mana Island, making it easy digging for today’s revegetation teams. A hundred thousand years of seabirds can do that. Ross Webber wasn’t confronted with barren rock on Puangiangi when he established his vege garden and orchard, rather a deep, free-draining, moisture-retentive soil.

Now, I see twenty-something Miss Canterbury on Petone beach (she is a red-billed gull banded red-black at her natal site in Kaikoura on the day of a big Ranfurly shield challenge by a naturalist with a sense of humour), resplendent in perfect plumage on a sunny winter’s day, standing aloof from the lesser of her species who eat chips, and reflect that even “common red-bills” have moved into the Vulnerable category now they have so few breeding sites left. And I’m well aware that there aren’t any petrel colonies on the windy hills around my home in Wellington, the last one possibly having gone about 60 years ago.

The present mainland colonies, natural and translocated, are often reliant on expensive predator management, including fences. We have an opportunity with the Puangiangi project to intervene inexpensively to create another seabird island, with its natural fence.

Puangiangi As a Seabird Island

There’s no doubt that Puangiangi would once have been a smaller version of Takapouwera/ Stephens Island, which even today holds two million fairy prions to name but one species. It was almost not even a discussion point to make seabirds the focus of our restoration efforts, but that decision does come at a cost and does limit what else we can do. Take weka (please): let’s say there were 500 weka on Puangiangi twenty thousand years ago, and 5 million of a mixed mega-colony of fairy prions, fluttering shearwaters, diving petrels, white-faced storm petrels, flesh-footed shearwaters and sooty shearwaters, with sundry outcroppings of half-a-dozen shag species, gannets, red-bills, black-billed gulls, terns, mollymawks, little blue penguins. The 500 weka would be very well-fed through grabbing unattended eggs, nestlings, weakened adults, but they wouldn’t make a huge difference to a population of 5 million birds. Contrast that with the situation in 2012. I estimated the population of weka on Puangiangi as 20 (that was a gross underestimate as it turned out, but 20 will suffice here). Let’s say we were able to re-establish  a colony of 20 pairs of sooty shearwater. If we left the weka there, it’s likely they would get many or all of the chicks each season. Weka are inquisitive with a good sense of smell and are constantly patrolling for new opportunities. Such a seabird colony would not go unnoticed.

If the burrow-nesting petrels lose an egg or a chick, there is no time to re-nest, and of course they can only afford the energy input of one per clutch. Sooties take several years before reaching breeding age also. Therefore, more or less any weka predation would send a nascent colony spiralling towards functional extinction, with only a few pairs of unsuccessfully breeding adults hanging on for any time. So if we were to have a go at re-creating Puangiangi as a seabird island, the weka would have to go. Weka are worthy of protection in their own right and ironically we have funded a project to re-introduce weka to an area of the upper south, so it’s not actually a no-brainer to choose seabirds over weka. However, there are more areas where weka are safe than there are islands where seabirds are safe, so we chose seabirds. Peter was able to secure a permit to catch weka and relocate them to the mainland, so the project was under way from our point of view.

Burrow-Nesters

Sooty shearwater, one of the bigger burrow-nesting seabirds, were holding on on Puangiangi and on Tinui’s southern satellite Takawhero into the 1980s. Ross Webber was well aware of them, and indeed had found a chick and kept it at his house for a short time, trying to feed it on bacon scraps. Visiting field workers, including Peter, had found remnant sooty colonies in the southern and north-eastern forests and Peter brought out some predator traps for Ross to deploy in the southern colony. We found the remnants of one during May 2012. But, as the rats slowly got on top of Ross, they slowly got on top of the sooties. It’s highly predictable that sooties would be the last burrow-nester there: they are bigger and feistier than the fairy prions, fluttering shearwaters and diving petrels that are generally more common in Puangiangi’s latitude, and would be a match for a rat or a weka coming down a burrow, leading with its head. That protection would extend to incubated eggs, but after the egg hatches and the adults leave the nestling for longer and longer periods to go as far as the Polar Front to gather food, then the insidious numbers game of predation begins. That game was over perhaps a hundred years ago or more for the smaller and comparatively defenceless petrels and prions, but sooties hung on longest, before being wiped out or driven away.

Ross was pretty clear in conversation with Sue and me that he considered the sooties to be present for all of his tenure, but Peter and I looked for the old southern colony during what would be peak fledging week in May 2012. We should have found the old burrows to be clean, with squirts of bright white droppings away from the entrances, clean beaten ground from all the comings and goings and gardening, and a distinctive smell to the burrows. Instead we found cobwebby burrows, drifts of leaves blocking others, penguins in some others and weka following us around. We were to be starting from scratch, but of course the island was at least rat-free thanks to the efforts of 1999 described in another article.

So, let battle commence. It’s an important job every trip to catch as many weka as we can fit into the pen Dad built for them in the shed. Once in the pen, they get to forage for insects and worms in the leaf litter we bring in, and eat specially prepared meals and our leftovers- cheese, pasta, eggs, blue cod frames. In reality they mainly occupy themselves knocking over their water, trying to escape and staring balefully at us when they jump on to the top of the sacking we have hung as little refuges for the more timid weka to hide from their more aggressive brethren. We try to limit catching to near the end of a trip so we hold them for as short a time as possible, and they are largely very resilient. To start with, we transported them in cardboard or Corflute carry boxes, but after a near miss with one in its box almost being blown over the side of Aston’s barge, and the fact they just would not settle in the boxes, scrabbling around the whole trip into Garne and Saville Scenic Reserve, Claire made up some heavy canvas bags with tie tops. Like most birds, they settle well in the dark of the bags, even travelling two-up without incident if we run out of bags. At the release point they are tipped out of the bags and they orient themselves and run off impressively. We removed the 100th weka early in December 2015 and several times have thought we have gotten the last one. I’m still aware of a very few as I write though.

At the start of this article, I said we have helped with some chick translocations. These are intricate processes developed here by our endangered seabird scientists (ambiguity deliberate).  Almost every individual of each species of burrow-nesting seabird returns to nest in its natal colony, often coming back after however many years they spend at sea before beginning to breed, to within a few metres of where they were born. This fixing on their natal colony is thought to be learned during the nights (1-20 or more depending on the species) they emerge from their burrows to exercise wings and shed down and weight before they fledge. Only through over-population at a colony (unlikely these days) or in rare individuals with inclinations for wandering beyond the norm, or through some not-yet-understood at-sea interaction with others, will dispersal occur. The simple act of grabbing an adult and putting it in a hole somewhere else will in no way over-ride this loyalty to the natal site. People have tried- the adults fly back. However, moving chicks before they develop site loyalty, and feeding them until they fledge, might induce those birds to return as newly minted breeders to the new colony.

Chick translocations have been done with many species of petrels in New Zealand, many successfully. People like Brian Bell and Graeme Taylor practised on common species first, refining techniques so that endangered species like taiko and Chatham petrel could be tackled with justified optimism. Realising that canned sardines (whizzed up with water and fed by syringe) were a transportable, non-perishable means of approximating the chicks’ natural diet, expanded the type and remoteness of site which could be considered for the technique. People with attention to detail, like Helen Gummer, came to tailor the feeding regime individual by individual- not just sticking to a species template- by careful weighing and  measuring in the field as each project ran its course. Building up the numbers of trained people, such as Sue, means that chick translocation is now mainstream thinking for ecological restoration projects where common petrels are the target, and for work with the endangered ones too.

The typical three-year cycle of translocations is costing around $60,000 plus whatever notional price one wants to put on the volunteer chick-feeding labour. The maximum number of chicks that can be handled at a new site is about 240, with a target return rate of about 30% after however many years it takes for the species to reach breeding age. An analysis of the completed translocations around the country, however, indicates that many sites are going to need top-ups to give the new populations a statistically good chance of becoming self-sustaining. Funders and community groups should be thinking of a decent six-figure sum and bulk volunteer wrangling for a completed translocation project.  Puangiangi’s remoteness and difficulty of access and getting around suggests that chick translocation would be marginally achievable at best. Also, the community engagement plus of having large numbers of volunteers involved is not relevant for us. We have initially plumped for an alternative:

Speaker systems to attract seabirds are now a reality around the country. We’re up to our seventh I think, installed on the Kermadecs, Wakaterepapanui in the Rangitoto group, and now Puangiangi. A solar panel charges a hefty battery and, at night or in the daytime depending on the species being targeted, the solid-state electronics inside a waterproof case play the tracks on a sound card through 350-watt outdoor speakers. The systems now cost under $2500 and they require little, although not zero, maintenance: the batteries don’t seem to last as long as they should and the SD cards eventually die, so the systems are not set-and-forget. We made a simple modification to one of the systems by adding a timer to allow finer adjustment of playing time than just day or night, and this is likely to put less strain on the battery. If the systems work, they attract adults, obviating waiting out the 2-8 years for translocated chicks to return as breeders.  We thought that Puangiangi would be a good candidate for the speaker method, what with a sooty colony not long gone with perhaps a few adults still alive that were born there, and large colonies of fairy prions to the north on Takapourewa, some of which might be enticed south.

The first site chosen was obviously to be near the bigger of the old sooty colonies, and we put up the speakers at the upper edge of the southern forest. It was a long, hot walk to carry in the heavy and awkward gear from the shed and we were grateful for the help of Roy Grose and Chris Birmingham from DOC, who were visiting us to catch up with Peter and to eyeball me. Sue and I were a bit worried that good intentions by DOC to assist us with the project might become subsumed by other priorities over time, but these immensely capable people gave me great confidence from the beginning of this project. Chris was at the time working nearby on Maud Island but has regrettably left for Te Anau to a dream takahe job along with his partner Linda Kilduff and new baby. Roy is sticking it out through the endless restructuring of DOC and still works in the region albeit with ever larger responsibilities.

Peter and I put in some starter burrows in the grass around the speakers and turned the system on, the sound card carrying recordings of sooty shearwater, fluttering shearwater, fairy prion and diving petrel. We gave visiting botanist Barbara Mitcalfe a demonstration and she thought it an awful cacophony, but it seemed to work for the birds. We also rigged up a trail camera and hooked it up to the cellular network through a big Yagi aerial fixed high up in a nearby akiraho. At 1 AM on 3 December 2012, a month after the system went in, I got the first photo (at the head of this article) sent to my phone back in Wellington, of a sooty shearwater on the ground.

The site saw quite a lot of activity. During March-April 2013 for example, the camera recorded birds on the ground on 15 of 56 nights monitored. We identified sooty shearwater, fluttering shearwater (two on the ground simultaneously several times) and probably diving petrel.

One strange observation was a morepork/ruru having a go at a small petrel on the ground next to the speaker system. Did we encourage unusual behaviour or are ruru expected to be predators at seabird colonies?

On the strength of these results we got another two sound systems. One was installed at lower altitude than the active one, at the edge of a tussock/ salt turf area which looks ideal for smaller petrels to dig burrows. The best we managed in two years there was some feathers and, separately, half a diving petrel. There was no sign at all of burrow construction and we have since shifted the speakers to above Boatshed Bay and put in a gannet tape.

A third system was put in at the north end, within earshot of any of the millions of petrels on Takapourewa that might fly a few km south when foraging. Cameras showed a good rate of visitation by fluttering shearwater, and we promptly added some shearwater decoys to help things along. The initial fluttering shearwater model was beautifully made for free by Richard de Hamel and then a two-piece fibreglass mould taken from that. Peter spent wet evenings in the shed on Puangiangi making resin shearwater halves, which were then glued together and painted. They look great, but neither they nor the speakers enticed anything to occupy burrows at the site. We’ve since moved the decoys and sound system with a new flutterer-only SD card to a central site reminiscent in aspect of the colony on Long Is., and looking out to where flutterers feed and raft up at times. Again we have had fluttering shearwater visits, but no nesting so far.

In early December 2013 we returned to the original speaker site and found breeding sooty shearwater. There was a newly-refurbished look to the old natural burrows, and we found a couple of occupying birds at great cost to Peter’s arm. In January we went back with a burrowscope, courtesy of Nicky Nelson at Victoria University, and found 16 incubating birds. The number of active burrows dwindled away during summer and autumn though, and three chicks got to the stage where they came to the surface at night-time, exercised their wings, shed down, lost weight and eventually took off in early May.

Helen Gummer points out that this might be the first successful example of acoustic attraction of sooty shearwater which have gone on to (re-)found a breeding colony. The colony looked abandoned during 2012, and we first noticed adult sooties in December 2012, a month after the speaker system was installed. The burrows were obviously active the following season (beaten earth, smell, clear burrows and so on) and I don’t think I would have been so stupid as to miss such signs in 2012.  In possible support of this claim, we also found an old sooty burrow grouping elsewhere on the island away from any speakers, and there has been no activity there, despite weka pressure all but vanishing island-wide. I guess it’s possible though that if 2011-12 had been a no-fledge season, then the colony might just have looked sufficiently forlorn in May 2012 for us to pronounce it extinct at that time. We still think the speakers did work, but must allow for the possibility that we were fooled. We’ll never know.

Apart from trying to catch the last weka, we don’t plan on actively intervening with our small sooty shearwater population. We want to disturb the birds as little as possible and are not intending to band the chicks or the adults. We do want to know the fledging rates each year and to get an idea of the population trend and have been surveying with the burrowscope each breeding season and monitoring with cameras. Seabird expert Graeme Taylor reckons burrowscoping in the daytime is about as intrusive to the chicks as their parents returning with food and we concur.

The main colony at the south has 28 GPS-mapped burrows. In early December each year, we are detecting 15-25 active nests. In a good year 15 chicks are fledging in early May, but in other years we are seeing none or only a few fledge. Other colonies around the region are variable also, where sometimes the burrows flood and chicks drown or die of hypothermia. In other years there are thought to be at-sea problems with food supply, with the adults giving up on returning to feed the chicks if they are weakened by having to fly too far for food. This could be a bigger problem with our presumably younger breeding adults given that the colony is likely to have been reestablished only after the speaker system was put in.

For our first burrow check in early December 2017, we were joined by Jo Sim, Brook Mells and seabird specialist Rua. The southern colony had 23 active burrows, and the sniffer team found two new northern colonies of 5 and 2 burrows, 5 of which were confirmed to contain sooty shearwater. The larger of the two new colonies is quite unstable and we are likely to collapse burrows if we go there often, so we have decided not to actively monitor these new sites. None of the hoped-for smaller petrels were found despite a comprehensive look over the island (Jo recorded the search track with her GPS and plotted it for us).

Despite weka still visiting the burrows up to 2022, we have not recorded any weka kills. This includes burrows we had a camera on, visited by weka but going on to fledge a chick. In 2018 a chick was killed at the burrow, most probably by a falcon from the fact that only feathers were left. Richard Cuthbert in his book Seabirds Beyond The Mountain Crest records falcon taking Hutton’s shearwater at the burrow. We have found one adult hung up in a shrub, and a dead, partly feathered, chick at the northernmost site- too early to be out of the burrow- perhaps indicating it attempted to fledge after not being fed.

In 2020 Henrik Moller reviewed what we were doing with the sooties and he noted that sites he has been involved with can have a proportion of false negatives, when the burrow appears empty but the chick merely moves deeper away from the probing burrowscope and can’t be seen in time. We do have examples of negative burrowscope results where it was obvious a chick was present (swept entrance, excreta, smell) and a camera indicating that a chick later emerged. Now that I in particular am more aware of false negatives, I’ll be making special effort to avoid unconscious bias in effort and attention when looking at a burrow that measured empty the previous month. Henrik also suggested that we look more widely for evidence of colony expansion than just the monitored burrows, as obviously this would be the desired outcome rather than just monitoring burrows for monitoring’s sake. We were aware of that but his comments helped overcome the ever-present activation barrier to searching the less-than-level terrain. Acting on this we found one new burrow over the entire accessible forest floor, which we decided not to include in the monitored group given the likelihood of taking a decent slide downhill while getting to it. To be certain, I tested this likelihood and confirm that gravity does indeed work on site.

So, what’s going on then? Our best guess remains that the colony is just like Titi Island nearby, which has been static or shown only very slow growth over the last 20-30 years. The Cook Strait area is not rich in sooties and may be a bit far from the southern feeding grounds, so inexperienced breeders (like we allege ours to be) may not be invested enough to carry on with chick feeding if the krill moves further south in a given season. Henrik Moller also points out, ominously, that the large southern colonies of sooties have been declining an average of 2% per year. For a bird that lays a single egg in a season and not every year, that is a path to extinction and mirrors the numbers that prodded the Key government into a small amount of action on kiwi. Maybe our role is just to hold the line on a small outpost colony until population-wide declines can be fixed (if we as a country care enough), rather than look to the sooties by themselves to turn Puangiangi into the seabird island it once would have been. We need to accept that the island is more likely to really get pumping seabird-wise if we can attract some fluttering shearwater or one of the other petrels (not forgetting little penguin and gannet as nutrient-bringers-in either) that are more common locally.

Other Seabirds

Red-billed gulls live in the area seasonally, feeding on schools of small fish and concentrations of crustaceans. Once we saw a little bay on the eastern side with red-bills all but walking over one another to feed on some crustaceans which had filled the bay. Red-bills don’t breed on Puangiangi and we don’t have any idea which breeding colony they come from. They have contributed to the nesting success of the resident pair of karearea though. Their 2014 nest was littered with the beaks and feet of red-bills, the only pieces they didn’t seem to have eaten. Red-bills are not far short of the size of the smaller male karearea and if they had caught them close to the sea, it must have been a feat to carry them to the nest site at about 60 m altitude.

Black-backed gulls are quite common. A pair of reef heron is often seen, as are white-fronted tern, the occasional Caspian, and various shags such as king, little, pied and spotted. There is a thriving breeding colony of spotted shag, spread out from the northern tip of the island and along the eastern side, nesting adults and young being seen from the sea in crevices in the cliffs.

Little penguins seem to be common, and they are encountered at the sooty colony and all around the island. They also nest under various man-made structures such as Ross’ house and one of his old pottery kilns, which is housed in a converted mussel float.

None of these birds seems to need human interference, but we are trying to establish a breeding colony of gannets. Their regional breeding colonies are thought to be full and thriving and they are often seen fishing in the area. A grouping of generic fibreglass boobies, sourced commercially and painted up in Australasian gannet colours by Peter, has been set up above Boatshed Bay, on what we hope is an attractive, clear site. A speaker system broadcasts the sounds of a gannet colony from dawn to dusk, and indeed we did seem to have some early success. Peter was checking the speakers and I was looking down from the spur, frantically signalling to Peter that he should look behind him. A gannet was there and unconcerned at being a metre behind Peter. We took it as a sign that the decoys were good ones, on two counts. A gannet was also filmed staying overnight but there has been no nesting so far.

Lastly a bit of product endorsement which might be of interest to the seabird folk. We had a long-term loan of the current state-of-the-art NZ-made burrowscope, but needed to give it back. Thanks Nicky Nelson, the loan much appreciated. They work very well, but run at $5000 and are quite bulky to carry around, albeit much less so than earlier iterations by other makers.

We had earlier tried out a little colour inspection camera sold to tradies, brand not remembered, which was pretty useless. A few years ago, inspired by the videos on their site, I bought a specific inspection camera, the Tradesman Record from UK firm eazyview.com. This has proved to be at least the equal of its larger cousin. The screen is colour and has more than adequate resolution. It can also record photos and video clips, in my case usually accidentally as the record button falls rather too readily to hand. I suspect the daylight LEDs will lead to more false negatives than the infrared ones in big cousin, but it’s quick to deploy, get a handle on what the camera is showing and finish the burrow, so I think it will prove only as invasive as the big one. The colour display is better at showing up downy chicks against dirt than the big monochrome instrument. It is easy to deploy and direct, with the flexible camera wand being of just the right stiffness to be controllable in the average to shorter burrows we have. The big one could not get any further than the new one down the longer burrows before we lost control of it. It’s more than possible to do a burrow by yourself, but we still prefer to have one person getting the wand into the burrow and the other watching the screen, as for the big burrowscope. Battery life is excellent, and we can do two months of checking 30 burrows, without recording, on a single charge of the 3 Eneloop Pro AAs (bought separately). Alkalines can also be used and there is a setting to select battery type so it doesn’t shut down early on the rechargeables. The supplied cheapie carry case protects the camera nicely and stuffs into a day pack easily. The afterthought pockets in the case are useless for spare batteries and the screwdriver you will need to change them, unless you like throwing small items down a hill in a dark forest when you unzip the case, but I suggest you get a little accessories bag and chuck that in the case instead. I haven’t managed to break it yet, or scratch the camera lens. It is also good for peering into kakariki nests (yes, there will be an article on kakariki some time soon).  Highly recommended, and landed in New Zealand for about $200. You will not notice the affiliate links at the bottom of this article, because there aren’t any. I have not communicated with the company other than to buy the product and they had no input to this review.