Oysters

I would guess that almost every known sea creature has been tasted at some time, except perhaps the Box jellyfish and Brain coral. Bread, butter, pepper, salt, tomato sauce and specimen A. Most fish are edible. Most crustaceans, kina, some sea squirts, turtles and sea anemones and almost all molluscs are on the menu. I’ve tried a range of them. Coming in at 327 in the ranking is the kina. There is disagreement about the top spot but only by people who have never actually tried oysters, or perhaps they are just looking for a fight.

Auckland Rock Oysters

We, the public, rarely get to see an oyster in its true majesty. The largest are skimmed off by ‘the trade’ for their own consumption and rascally fish and chip merchants cut any half decent one into fractions before battering them.

You can get your own by puddling around knee deep in estuaries and harbours at low tide and you can find larger ones washed ashore after rough weather, often with a sea tulip attached. They last well, sealed in the shell – often a week or more – unless some walrus or carpenter beats you to them. As a last resort you can buy one or get acquainted with an oysterman.

Oysters are best raw and best opened by yourself. This way you’ve earned it, you know it’s fresh and your enemies haven’t had a chance to poison it. Listen for that little squeal when you bite into one.

The term ‘oyster’ is applied to several different groups of bivalves of a flattened and irregular shape. The best known one is probably the pearl oyster, quite unrelated to the Bluff oyster. Pearl oysters produce nacre, a form of calcium carbonate, which lines the inside of the shell and coats grit trapped within it. This sometimes forms a perfect pearl.

Many shellfish produce pearls with the largest coming from the Giant clam.

In New Zealand we have three food oysters: the Auckland rock oyster, Pacific oyster and Bluff oyster. Once it was believed there were more but most of the discounted species are synonymous with the Bluff oyster. Huge fossil oysters with shells 8cm or more thick are found at Springhills, Southland, but for all their bulk, there wouldn’t have been much oyster in them.

Fossil Oysters from Springhills

Oysters were harvested, bottled and exported as early as 1830, the first food exports from New Zealand. There were extensive beds in Port Adventure which were accessible at low tide. Small vessels would be grounded and the oysters shovelled aboard.

Oysters are protandrous, being males first and then female. They produce copious eggs, only a few of which survive to become oysters. As in most species, vastly more eggs than required are produced. Nature is an enormous restaurant and 99.99% of all eggs and larvae are eaten. Oysters, like almost all bivalves, are filter feeders. They generate a current and trap minute food particles.

All is not joy in oysterdom. We constantly worry whether the quota may be too large. A protozoan parasite, Bonamia sp., has had a serious effect on oyster numbers since about 1985. Pacific oysters are in the news as there as been a big die-off of juvenile specimens in Northland oyster farms. Let’s hope its not a new disease!

Blue Penguins

I can’t remember which bird I voted for as New Zealand’s favourite in the recent poll. I think it was the kea but the Blue penguin is pretty near the top of the list. My first experience of penguins was on Kapiti Island when I was a kid. We lived in Palmerston North and visited the island a few times as my father was doing a botanical survey there. Penguins nested under the boatshed, near the whare and reportedly, even under the trig on top of the island. They were noisy and anyone presuming to have a restful night in a hut accessible to penguins was going to be disappointed. I did frequent beach walks along the Himitangi and Foxton coast recording dead birds, and we found penguins frequently.

Sometimes there was a major wreck with hundreds of corpses – these mass die-off are fairly frequent, particularly in the far north. I carefully cleaned up a skeleton and mounted it. You can see that although it has the same bones as all other birds, some of them are extremely modified. The tarsus and humerus in particular are very distinctive and these are key bones for identification when you have an assortment of fossil bones in marine sediment.

There are a few places to see them around the Southland coast. I’ve seen one off the Bluff wharf several times and they are common in Bluff Harbour, Foveaux Strait and around Halfmoon Bay.

Once you know what to look for you see the dark head and a little of the body showing. They aren’t as buoyant as a duck and float low in the water; this near neutral buoyancy helps when diving, as a dive can last several minutes and take the birds down to 20m or more. The most famous Blue penguin colony is at Oamaru where you can have a grandstand view of the birds coming ashore in the evening. The world’s best-known penguin arrival is on Phillip Island in Bass Strait near Melbourne. 3.5 million visitors each year admire the throng of staunch penguins emerging from the sea at dusk and making their way inland. This is the Fairy penguin, almost identical to the New Zealand form. The most distinctive of several New Zealand varieties is the White-flippered penguin. I’ve found two in Southland. They have a prominent white margin on the leading and back edge of the flipper, a pale blue-grey plumage and a white tail. Most of these are in colonies around Banks Peninsula so Southland’s examples might just be vagrants or perhaps white-flipperedness is a mutation that shows up occasionally in the local population.

two stuffed penguins together - a White-flippered and a Blue
to show the difference in flipper colour.

I’ve helped band penguins – feisty is the best word. They hang on with their beaks to the skin on the back of your hand, scratch and batter you with their flippers. The band is put on the wing as it tends to snag seaweed if it goes on the foot.

If you don’t want to venture near the sea you can always visit the penguins at the Antarctic Centre. I haven’t quite worked out what it’s all about. You start off in the Antarctica – and its very nicely done – then you are directed into another part of the building where there is a pond full of penguins with bits missing – flippers, beaks and feet – and you have to watch them being fed. Then you find that there is still two thirds of the Antarctic Centre to visit in your remaining ten minutes – weird. Not a good advertisement for penguinkind and a crass attempt to cash in on the penguins which aren’t associated with Antarctica at all. The misconception is widespread however. I heard of one woman who found a Blue penguin on a beach in Northland. “Poor little thing,” she thought, “it’s come all the way from Antarctica. It must be feeling hot,” so she put it in the freezer, not the fridge, the freezer.

Golly, it’s gorse!

I’ve known gorse a while. I don’t remember much of it about when I was growing up in Palmerston North but when we made our infrequent trips to Wellington there it was, clothing the hills in a yellow blanket, for it flowered much of the year. Wainuiomata I think was gorse’s spiritual home, it’s Turangawaiwai.

Gorse was an early introduction, for hedging. It does this remarkably well. It grows rapidly in all manner of climates, it can be cut back mercilessly and still thrive and within a couple of years it forms an impenetrable barrier to stock. Those are the good things about it, added of course, to its suitability for honey and pleasant smell.

The bad thing about gorse is its ability to spread. At one year old it flowers and the seeds can stay viable in the soil for forty years or longer. Because of its rapid growth and unpalatability and tolerance of disturbance, drought and flood, it colonises habitats such as wetlands, tussock grasslands and riverbeds where it rapidly displaces the native vegetation.

The problems with gorse would have been recognised within a few years of its arrival but control techniques were limited then, and once it had a toehold, its spread was speedy and predictable. Cutting, grubbing and burning, work to some extent but continual follow-up work is needed as cut stumps sprout and the seed in the soil germinates in the high light conditions and fertile, black ash following a fire.

Rapid planting with other species such as pines or poplars may limit gorse a little but no native species will outgrow it in its early years. Up in the far north gorse is spindly and weak. It’s too warm there for it to thrive but it does shelter native seedlings which soon overtop it. In Hinewai Reserve on Banks Peninsula the gorse-covered hillsides were left untouched, much to the surprise of many involved with habitat restoration. This proved the right answer because natives have come through the gorse which dies off as it is shaded out.

Gorse is a good nursery crop there but is this true for Southland? Massive, dense and lightless gorse forests seem to exclude native seedlings and add decades of gorse seeds to the environment before anything like a break in the canopy allows a native to sneak through. The succession may work eventually but tolerating gorse means that it spreads far from the uncontrolled area in the meantime. One place where gorse has been replaced is at Omaui. The council reserve had been cleared of bush and converted to pasture. Gorse took over but as you walk up to the lookout you can see where manuka has beaten it. Huge gorse trees five metres high and 20cm through the trunk are struggling to keep their foliage in the canopy. Everywhere native seedlings are growing where the manuka canopy has started to break up and eventually forest will return.

Very old gorse at Omaui, struggling to
keep up with the surrounding manuka

The Gorse weevil was imported in one of New Zealand’s first efforts at biological control. The weevil lays its eggs in the seed pod and the growing larvae devour the seeds. When the mature pod bursts open it flings little weevils everywhere instead of gorse seeds. If an insect is capable of experiencing fright, this surely a good test. You are settling down to a quiet evening in the pod with your brothers and sisters. Someone is telling spider jokes, someone else is weevling a wall-hanging and another is reading ‘A History of Beetles, a who’s-huhu of the Coleoptera’. A framed homily on the wall says, ’See no weevil, Hear no weevil, Do no weevil’, the latter referring to the strict code of ethics observed by weevildom. Another decoration has the national anthem ‘Wee vil overcome’ – not a vain sentiment considering ten percent of insects are weevils.

Suddenly, with no warning apart from a couple of creaks, the home cracks in half and weevils, furniture, toothbrushes, everything is shot out into space. Soaring through the air like miniature Weevil Kneivels, the family scatters. Post traumatic shock syndrome takes most of them but the survivors – pale, unsettled and showing a range of addiction problems – eventually pair up and lay eggs in a new pod, but perish with the first hint of winter.

Wally weka.

I’ve just had a week at Deep Cove with three classes from St Peters College. It was a good week. We found the glowworms, did the old Doubtful Sound Track three times, sampled the water three times and climbed to Hanging Valley three times. The number of wekas around the hostel is growing thanks to stoat trapping in the area. A few years ago it was expected that they would disappear but there are a dozen or more in the vicinity and we encountered other pairs along the road. They are unusually dark and often called Black wekas.

North Island weka

The weka is part of the large order that includes the pukeko and takahe, rails and crakes. There is a single species divided into four subspecies. These are the North Island weka, the Western weka which is found in Marlborough, Nelson, the West Coast and Fiordland, the Stewart Island weka and the Buff weka. The Buff weka is native to the eastern South Island but became extinct around 1920. Fortunately it had been introduced to the Chatham Islands where it was common enough to be both a pest and a menu item. I tried one there in 1981. It was gamey of course but quite edible. Its value as food was important to Maori and to sealing gangs left to their work on the rocky coasts. The curiosity of the bird, its abundance and ease of capture made the shopping easy until they got wary.

They were called woodhens by the settlers but are usually called wekas these days, or ‘weka’ if you subscribe to the idea that Maori words that have been absorbed by English don’t get the ‘s’. I don’t.

There is the odd Woodhen Cove around and the strange Three-legged Woodhen which is an anchorage on Stewart Island, three legs apparently being an unusual number for a bird. The most famous placename with weka in it is Weka Pass which you go through on the way from Christchurch to Hanmer. Not much of a pass but there is a restored railway there.

Wekas disappeared from around Invercargill over 100 years ago. They are feisty but no match for cats and ferrets. As soon as the stoat, weasel and ferret were brought in for rabbit control people noticed the drop in weka numbers and they were soon all gone apart from the more inaccessible places. Cats eliminated them from much of the main Stewart Island but they have been brought back to the Halfmoon Bay area with some success and they thrive on Ulva Island away from interference. They are great thieves and are easy to distract with shiny objects. As the steamer Waikare sank in Dusky Sound in 1910, the passengers watched it disappear from the fastness of a nearby island. One female passenger removed her ring and it was promptly stolen by a weka. By the stratagem of enticing the weka with a silver teaspoon to which a cotton thread was tied, the bird’s hideout was located and the ring recovered.

Western weka

When I had scouts we had a Weka Patrol. Kids like to associate with a critter of some character such as a Kea, Eagle, Kiwi or Tiger. There never was a Fantail Patrol nor a Budgerigar Patrol. The Kiwi Patrol had a stuffed weka which the Weka Patrol wanted, the Wekas had a deer head that the Stag Patrol coveted but the Stags didn’t have anything to offer the Kiwis to secure a deal. They had to be content with a cow skull to which two right antlers were bolted. The Weka Patrol painted their den purple. The ceiling was an old parachute and they had a genuine porthole in the door. The Venturers liked this den as it had the best seats. They borrowed the Wekas’ kettle and stole their tea and biscuits. The scouts spiked some teabags with alum which makes the milk curdle and settle in the bottom.

Bringing in the birds.

Natureblog July 2010

Benny Hill thought he had a talent for bringing in the birds but he was always upstaged and to the tune of Yakety Sax, fled the chaos he had caused. Girls aren’t called birds much these days but various bird names are applied across humanity to showcase our attributes, usually the deficient ones. Dodo, turkey, goose, vulture … you might be able to continue the list.

Attracting birds is an age-old human quest; we’ve done it to catch them for food and for conservation and because we like to have them around. The art has attained its highest expression in the duckhunter. There are no limits to what a hunter will spend or to how much trouble he goes to to camouflage himself and build himself a little house in the swamp. I don’t know if anyone has mentioned it to a duckhunter before, but it is much more fun to visit a supermarket and get your bird there. It’s cheaper, it comes plucked and gutted and its not full of steel shot.

greenfinch

There’s a bit of science in attracting birds to your garden. There are around 30 species in Southland that might land in your trees or wander across your lawn. It depends very much on the size of section and proximity to the bush, ponds or parks but you can do your bit to help.

I think the most important factor is height. I was contacted once by a school which wanted to attract birds. “We’ve cut down our pines, macrocarpas and gumtrees. What should we plant to attract birds?” I suggested pines, macrocarpas and gum trees would be a good start. Birds like height. They feel safer from predators, it’s easier to take off from a high branch than the ground and they can see what everyone else is up to. Tall trees are necessary for most nests. Bellbirds, tuis, magpies, White-faced herons, finches, sparrows and pigeons need that height, and fast-growing trees are the answer. Other birds – silvereyes, dunnocks, blackbirds, thrushes and starlings for example – don’t need the tall trees and utilise buildings or lower shrubs.

What can you plant for birds to eat? This is less important than height but a good practice.

Many plants, native and introduced, provide food for garden birds and a variety of plants can make a real difference to what lives in your garden. Unfortunately some introduced plants with edible berries are pests. These include Chilean flame creeper, cotoneaster, bittersweet, holly and barberry which are all spread by birds. One fast-growing species with edible berries is karamu Coprosma robusta, but although a New Zealand native, it is not native to Southland.

Redpoll

Other useful natives which occur naturally in Southland are wineberry, Tree fuchsia, Red matipo, pate, Three-finger, Cabbage tree, flax, Black matipo and various shrubby coprosmas. All grow rapidly and produce flowers within a few years of planting.

These species are of benefit to nectar-drinking and fruit-eating birds but plenty of other birds use trees and shrubs for a source of insects and spiders. Kowhai, laburnum, Tree lucerne, plum and willow leaves are eaten by pigeons but by attracting them to an urban garden you may be exposing them to cat predation.

Seed-eaters such as finches, yellowhammers, thrushes and sparrows need open space as they do much of their feeding on the ground or close to it.

Only a few species of birds will use a nest box. Examples are starlings, riflemen and grey teal but the starling is the only bird you can be sure of attracting to a nest box in town. This can be a mixed blessing. Although it is educational and entertaining watching the antics of starlings inspecting the nest box and filling it with material, they can be aggressively territorial and the growing chicks can be noisy. The nest box needs to be installed high in a tree, under an eave or in a place where the birds are confident it will be inaccessible to predators. A starling nest box needs a hole 58 mm across and the dimensions of the box should be around 250 x 300 x 370mm. An optimistic bird enthusiast might try to attract a Little owl. They like a 70mm entrance hole in a box about 800mm long and 200mm width and height.

Supplementary feeding not only attracts birds but it provides a vital food source for them in winter. Silvereyes probably rely on sugar-water to sustain them when there is little else around. I provide sugar-water for silvereyes, tuis and bellbirds. I put out food scraps such as bones, peelings and over-ripe fruit which are picked by starlings, blackbirds and silvereyes. Slices of dog roll in a netting bag, suspended well out of cat and dog reach, are attacked by silvereyes and starlings. Wheat and birdseed bring the finches and sparrows. A word of caution about seed cakes – as seeds are dislodged they fall. Make sure your feeder is above open ground otherwise cats lurk and take the food chain a step too far when your finch starts foraging in the shrubbery. Bird food also attracts rodents so keep those traps on a hair trigger!

Moas and me… moas and I? Whatever

Giant Moa

 My first moa experience was an excavation on my uncle’s farm in North Canterbury. This was only a few miles from Pyramid Valley, the most famous moa site of the time. We dug down into a patch of sand that had a spring rising from it and we found moa toebones and other small bones which would have been from kiwi, Native goose and things like that but I don’t think we bothered with them, just the impressive toes. The site was a bog in prehistoric times, trapping the big birds as they came to drink or feed on swamp plants.

Moa bones are quite common. I often see scraps of bone in sandhills or old midden sites and a few times I have picked up bigger ones. We found part of a skeleton in sand dunes at Colac Bay a few years ago and I helped dig bones from a paddock at Dunrobin after the farmer had cut a trench for a drain and started scooping them out.

I’ve never found a skull. I guess that if the bird gets mired it’s the head and neck that get eaten or weathered away first, leaving the leg bones underground. The bones survive if they are buried in a swamp or desiccated in a cave or in dry sand. You also get bits of eggshell with the bones, and the gizzard stones which the bird swallows to help grind its food. The stones wear against each other and they can have distinctive flat sides. You can make a gizzard by filling a screw-top container with pebbles and bits of fruit. Give it a vigorous shake and drink the goo. I guess you could hear moas coming by the rattling.

A school in Central Otago found so much eggshell they packaged it up and sold it as curios. One scout troop all had woggles made from slices of moa legbone. It’s very hard and polishes up nicely. Someone is making the ivory parts on bagpipes from moa bone. Talking of bagpipes, I wonder what the screech of the moa was like? Back in the old days Scout patrols had prescribed calls. The Wolf Patrol had a howl, the weasels went “eeeeeeee” and the moas’ war-cry was “pee dunk, pee dunk, pee dunk.” I can’t imagine what that sounds like, probably more a noise you would get out of the tuba than the bagpipes. I wonder what the Parrot Patrol had for their call? “Who’s a pretty boy then? Who’s a pretty boy?” The only Moa Patrol I remember was an ad-hoc one formed at an overgrown campsite. It
 was actually the Mower Patrol but they didn’t know that until too late.


At Colac Bay ~1985














 
I was given some actual feathers which were found in a cave. They are very rare as are any of the soft tissues. Otago Museum has a dried leg from Central Otago and Southland Museum has a skeleton held together by dried sinews. It was found in a cave at Lake Echo not far from Te Anau.

What of the possibility that moas survived into European times? Zilch. Research has shown that they were gone within a couple of hundred years of humans getting to New Zealand. They could obviously stand no hunting pressure whatsoever. Research has also shown that they are not Moa’s Ark relics at all. We had imagined their ancestors waving goodbye to their Australian cousins when we parted 80 million years back. Instead, their origin is much more recent and they are descended from flying birds that reached New Zealand only a few million years ago so despite their similar appearance, emus and moas are an example of convergent evolution. This finding is one more piece of evidence to support the theory that New Zealand was totally under water about 25 million years back, and that all terrestrial life colonised since then. This is tricky when it comes to the tuatara and native frogs though.

More sea mammals

Common Dolphin

My first experience of cetaceans – that’s whales and dolphins – was a dolphin skull that my father brought home from Farewell Spit. I was intrigued. I already had an interest in skulls and so could identify the different bones that made up the skull – parietal, nasal etc.

My second encounter was on Hokio Beach south of Palmerston North where a friend and I were doing a beach walk, recording the dead seabirds washed ashore. This would have been back in 1968. In the distance we saw a grey shape, smoother than the logs which littered the beach and contrasting with the black sand. It was a Rissos dolphin, freshly dead and not too unhappy about it judging from his little smile.
This was only the second Rissos known from New Zealand – the first was Pelorus Jack who had accompanied ships through French Pass. We took his head but had to leave behind one of the glass floats we were carrying. The head sat in fork of a macrocarpa for a couple of years, then we cleaned up the skull and shipped it to the Dominion Museum in Wellington.



Decayed Cuvier's whale













 I’ve had a bit of a fascination with cetaceans ever since and I’ve salvaged sixteen different species from around New Zealand with skulls and teeth ending up in several museums. I’ve got used to the characteristic smell and I have eaten my lunch sitting on a whale, although because of penetrating quality of whale oil, you can smell whale for the next week until it works its way out of your hands. The bones are porous and saturated in oil; that’s what gives whales their buoyancy. Putting them in the compost heap for a year is the best way to degrease them.

My most recent acquisition is a fossil skull dredged from the Chatham Rise. About 50 of these are known, possibly all the same species and perhaps dating from the same time several million years ago. The skull is petrified – remarkably hard and heavy. It would have been buried in seafloor sediment which became limestone, then thrust above sealevel by land movements, eroded out of the limestone then swamped again to sit on the seabed a second time.

It’s always better to see a live whale or dolphin than a dead one. I helped in the rescue of a pod of Pilot whales on Victory Beach on Otago Peninsula in 1982. Half of the 60 were saved and we felt good about that. I’ve been whale watching at Kaikoura. It’s a great experience, and tourism is a better use of whales than killing them.

Times have changed. 100 years ago a pod of Pilot whales in shallow water meant everyone was busy trying to herd them ashore where they could be processed. In 1909 320 were herded ashore at Mason Bay. The lucky fishermen set up a tryworks and boiled up the whales getting 60 barrels of oil for their trouble. The oil was a lubricant and its high fluidity and absence of mineral impurities meant it was the choice for watches and sewing machines.

Dead Humpback

I’m against whaling but I’m all for utilising dead whales for whatever they can provide – meat, oil and bone. We have gone too far the other way in how we treat a dead carcasse on the beach. Why not salvage what nature provides? Today the sound of the ironware being sharpened has been replaced with the sound of wailing, blessings, prayers… ridiculous.

More

Seals

 Natureblog March 2010

I phoned a friend and his Scottish-born mother answered.  “He’s gone sealing,” she said.  “Sealing?” I asked.  “No”, she said, “sealing.”    I was unsure if this meant sealing the road or killing seals;  either seemed equally improbable since he owned neither a tar truck nor a seal club.  He did have a yacht though and he was away sailing.  It’s 1946 since anyone went sealing legally and this was just a single season after a gap of 22 years.  6,123 skins were taken from Fiordland and the Solander Islands, mostly by the crew of the Kekeno.  11 skins were collected from Otago and 53 from Westland giving a total of 6,187.  The season seems to have been called because Southland fisherman had come across a market for the skins in St Louis Missouri and so persuaded the government that seals were destroying the local fish stock.  They were then asked to organise a cull.  Very clever.

The first known sealing gang in Southland arrived at Luncheon Cove in Dusky Sound, Fiordland on 6 November 1792 on the Britannia commanded by William Raven.  They collected 4,500 seal skins which were taken to Sydney in 1793, the first commercial export from New Zealand.  During the life of the industry, it has been estimated the around a million seals were killed in New Zealand waters.
The skins were salted and eventually processed into fur garments.  There are two types of hair in a fur seal pelt - the long, grey hairs which give the seal its water-proofing, streamlining and characteristic colour, and shorter, finer hairs which trap air and provide insulation.  The skins were scraped on the inside until the bases of the long hairs were cut.  This hair was brushed out leaving the fine pelt which was trimmed and dyed.  There are said to be 300,000 hairs per square inch, resulting in a much denser fur than any available from land mammals.

The removal of so many seals would have had several effects on the ecosystem.  Other sealife, predated by seals would have increased, and muttonbirds were able to re-colonise more of the suitable nesting islands that had previously been kept flattened by frolicking seals.  At this time it is probable that Killer whales pods which depended on seals would have died out and been replaced by others relying on another food source.  Today stingrays are the main prey of New Zealand Killer whales which don’t eat seals at all.  
The seals that survived the slaughter were the ones that fled to sea as soon as men appeared.  These passed the scaredy-cat gene on to their offspring and so modern fur seals are much more wary of humans than they were 200 years back.

The seal population has recovered well, so well that they are a nuisance now to other primary industries.   Fishermen complain about seals taking fish and a stroppy seal in a salmon pen can eat a lot of dollars in a short time.  So is it time to start either culling or harvesting again?  An unofficial cull probably goes on with rogue animals being dealt to but is there a market for the fur and does the population need thinning?  Is it artificially high because of the lack of predator?
In some ways it is great that a population, once decimated, has recovered to the extent that we can harvest it.  In other ways a resumption of harvest takes us back to the bad old days, where exploitation quickly becomes over-exploitation.  We can’t eat them and there is a fair bit of feeling against killing animals just for their pelts.  Anyway, seals are popular with tourists – just watch the reaction of people seeing their first seals in Milford Sound or at Waipapa Point or Taiaroa Head – and the population, while large and growing, is still vulnerable to some dog diseases, to oil spills and loss through fishing practises such as the West Coast fishery which drowns some each year.
Let’s leave things as they are