Mud, mud glorious mud” begins the chorus of Flanders and Swann’s famous “The Hippopotamus Song”. But for all their miriness, the paddocks newly flooded by the sea, close to my Katikati home, were no hippo’s happy haunt. John Holwerda had recently purchased the low-lying property, much of its 16 ha or so at or below high-tide glorious mud” begins the chorus of Flanders and Swann’s famous “The Hippopotamus Song”. But for all their miriness, the paddocks newly flooded by the sea, close to my Katikati home, were no hippo’s happy haunt. John Holwerda had recently purchased the low-lying property, much of its 16 ha or so at or below high-tide exit pipe.
The returns from the marginal grazing the land provided was not worth the effort of maintaining it. Since most wetlands in the Bay of Plenty have been drained—little more than one per cent survive, for the most part highly modified and overrun with introduced predators—what better use for the area was there than to return it to its natural marshiness to encourage bird life? Unfortunately, the immediate result was the creation of a sea of mud, and the response from locals was instantaneous and deafening.
Indignation was vented in numerous letters of complaint to the Katikati Advertiser. Retired farmers hollered at the “waste of good productive land”. Others screamed about the smell of rotting grass, or how unsightly the place looked. John’s phone ran hot with abuse, and for weeks not a single person stood back and looked at the big picture. This was too much for me, so I too went into print, pointing out that, in the long term, the change was going to be for the good. My prediction was that those old paddocks would become the best place in the district for native water birds. I waited for the personal attacks to start coming my way, but all of a sudden the press went quiet and things settled down.
To my mind the area had always been a bit of an eyesore. The 30-year-old fences, standing in almost constantly damp ground and barely stock-proof, were well past their use-by date, while the pasture consisted more of weeds than healthy grass. Bird life was limited. On most days, pukeko could be seen by the score, and the odd pair or two of spur-winged plovers held breeding territories in late winter and early spring. Mallard often entered the drains to feed, joined by the occasional white-faced heron or kingfisher.
Within weeks of the floodgate’s removal, an influx of new birds began. The highest tides inundated about a third of the land with salt water twice a day, to a maximum depth of some 60 cm, and with the tide came a multitude of sea life—huge schools of little fish, together with small eels and mud crabs. Given the narrow bore of the pipe, the tide took a long time to cover the paddocks. By the same token it also took a long time for the water level to drop when the tide receded, giving birds an unusually long period during which to reap the abundant sea-borne harvest, which was very accessible thanks to the shallow water.
Pied stilts had always been present in small numbers on the mud flats of the Uretara estuary, occasionally dropping in to the paddocks when high tide covered the flats and prevented them feeding there. Now, in the new wetland, food was available most of the day; in fact, the stilts gave up on the estuary entirely.
Mallard were the first birds to breed in the paddocks the earliest ducklings appeared in August—but the stilts weren’t far behind, hiding their nests in tufts of grass in the drier areas. Unfortunately, around the end of September, when spring tides were at their highest, came a huge downpour. Most of the stilt nests were flooded, though a few early downy chicks could be glimpsed in boggy areas of grass. Their parents were very wary, and when they sighted people on the walkway along the top of the stop-bank, they would yap abuse, sending the chicks darting for cover.
The walkway is a popular exercise track for locals, a picturesque route from my part of town to the shopping centre. Many people walk their dogs along it, but fortunately a deep drain skirting the base of the stopbank and backed by a fence deters people and dogs from straying to where they could disturb the birds.
The stilts seemed to learn from the flooding and quickly re-nested, this time in increasing numbers. Many set up home right out in the open, though well back from the stopbank. The nests were platforms of dead, muddy grass 20 cm high, on which the eggs were safe from flooding at high tide. Colonial birds often nest in close synchronisation but these stilts had individual breeding clocks, some hatching eggs late in September, others still incubating in early December.
In early September, a group of local people set up rat-bait stations along the neighbouring shoreline. Even though nearly all the stations had to be re-baited every 10– 14 days right through to March (when baiting stopped), predation was minimal. Most pairs of stilts raised three or four chicks through to fledging, and twice in early January I counted over 30 flying juveniles.
This was the first successful nesting of stilts around Tauranga Harbour for at least a dozen years. It was impossible to count how many pairs raised chicks, as many of the nests were too well concealed to be seen from the stopbank.
The parent stilts were aggressive and wouldn’t tolerate other birds anywhere near their young, even after these were fully grown. The mallards got a hard time from them, parents and ducklings being driven off by repeated dive-bombing. By contrast, stilt chicks took little notice of anything, wandering off in all directions to feed. Only when their parents called the alarm, usually at the appearance overhead of a passing harrier, would they dive for cover in the vegetation.
The rat baiting was of benefit not only to the stilts, but also to the inhabitants of a strip of dense rushes along the edge of the stream. Here, fernbirds could regularly be heard calling, and on a number of occasions I also heard banded rails. Both species have disappeared in recent years from many areas around the harbour.
Although not natives, the mallard added avian interest to the new wetland all spring. Like the stilts, they nested over many months, and I might see up to nine families of ducklings on any single day. Some females raised as many as eight ducklings to maturity, a sight no doubt relished by local shooters.
The pukeko found the new, wetter conditions less to their liking than the old grazing. Numbers dropped in proportion to the area of grass lost. Mud and water are not pukeko habitat. Adding to the birds’ woes were the quantities of buckshot fired in their direction by the owners of a large plant-propagation business recently established on the opposite side of the stream. Pukeko had been found guilty of considerable destruction of young plants and suffered accordingly.
Winter and spring brought welcome swallows, mainly around high tide, when it was not uncommon to see a hundred or more of them swooping and diving. They could be so numerous it was a wonder they avoided colliding. Tiny flies, probably members of the family Dolichopodidae (which can be seen in vast numbers around estuaries), were thick above the wetland. The swallows’ energy seemed boundless, though occasionally I would see a dozen or so perched in a row on the fence wires.
The flooding of the paddocks brought the white-faced herons a whole range of new food sources, and it was fascinating to watch the various hunting strategies they employed. There was the standard stalk-and-spear method, the coiled neck poised to strike; the crouching attitude more typical of a reef heron; and, in the case of one bird, a highly energetic approach I’d never seen before. Wings outspread, it would race around the flooded paddocks in pursuit of tiny fish, sometimes bounding completely out of the water. I wondered if the energy expended chasing so small a reward was worth the effort. Photographing the bird in action was extremely taxing, as I was using a 600 mm manual-focus lens. Fortunately the camera was digital. Had I been shooting with film, with the power winder firing at five frames a second, the cost would have been horrendous, as a large percentage of shots were out of focus.
Shags of three species turned up regularly, mostly to dry out on the fence posts after feeding in the stream’s deeper waters. On one occasion a little shag, a little black shag and a juvenile pied shag were hanging out together, almost touching—a great opportunity to study the differences in their plumage. For some days, the juvenile pied shag was a regular at the pipe on the outgoing tide. Time and again, it would dive into the roaring torrent and come up with a small fish. I watched it at work one afternoon as it made a catch roughly every 30 seconds. It was fishing when I arrived and still going flat out when I departed 45 minutes later.
Even more exciting for me than the mass nesting of pied stilts was the influx of rare and unusual wetland birds. First, early in 2005, came the sighting by Elaine Fisher, editor of the Katikati Advertiser, of a most surprising bird feeding in the flooded paddocks just behind the Katikati shops. Elaine sent me an almost indecipherable photograph of what appeared to be an almost completely black bird feeding among the pied stilts. I went to see for myself, and on my second visit found a black stilt—well, almost a black stilt. It was mainly black but had a white face and a white backside—obviously a black–pied hybrid. In autumn and winter, small numbers of black and black–pied hybrid stilts stray up from the South Island to several North Island harbours, but to find one within a stone’s throw of the Katikati shopping centre was most unusual.
A few weeks later the hybrid stilt appeared once more, and it stayed on until early 2006. Near the beginning of December, I photographed it attempting to mate with a pied stilt. It was far too late to nest, and although I saw the pair scouting for a nest site, nothing eventuated. I hope to see a more successful attempt this spring (2006). The hybrid wasn’t entirely welcomed by his pied relatives. Time and again I saw pied stilts—probably other males—attack him and try to drive him away.
There are numerous pied stilts around the North Island with varying amounts of black-stilt blood. Pure pied stilts have black plumage at the back of the neck and white at the front. Some hybrids, by contrast, have a complete collar of black, while others sport more extensive black patches where non-hybrids are white.Yellow buttons (Cotula coronopifolia) have become common on the fringes of the saltmarsh.
Shoveler ducks put in the occasional early appearance, usually just two or three coming and going at a time. One day in April 2006, however, I counted 18. The males by this time were developing full breeding plumage: flanks a rich wine red, a white vertical band at the base of the broad, flat-tipped bill, a conspicuous white blotch on the rump, a blue-green flush brightening the neck, flight feathers and tail black, and a glossy green and pale-blue speculum adding a touch of sheer brilliance. Surely the shoveler is our most splendid duck. I cannot imagine how shooters can blast this magnificent creature out of the sky. Before the spring of 2005, in 25 years of bird watching and photographing around Katikati I had never seen one. A local hunter has boasted of shooting one out on the harbour 20 odd years ago, claiming it was the first he had seen in decades.
The arrival of the first few shovelers was soon eclipsed by the appearance of yet another new duck. I had seen the occasional grey teal on farm ponds further inland 20 years before; in fact, in 1984, I had known one pair to raise ducklings. But in December 2005 I spotted about eight of them in the new wetland, and numbers rapidly rose until I counted 170 in February 2006. Numbers then diminished until, come early May, I couldn’t find a single one.
Teal are quite nomadic in Australia, most parts of which suffer from frequent and prolonged drought. Water birds such as ducks must be capable of moving vast distances if the ponds and lakes in one area dry up and they are to find food-rich wetlands elsewhere. This is most probably how teal come to be in New Zealand. A few of them arrived in the country in the mid-1800s, and their numbers were boosted by another migration 100 years later during widespread drought in Australia.
In the wetland, through the middle of the summer, grey teal often gathered in large flocks at low tide. Pairs and small groups would gradually break away to feed at the edge of the incoming water. Other days they would be out on the harbour, and arrive in fast-flying flocks soon after the paddocks began to flood.
Not long after the first few grey teal had arrived, I spotted a male brown teal among them. This bird stayed for some months before disappearing as suddenly as it had turned up. Most probably it came from among some brown teal released, and now breeding successfully, around Port Charles, near the northern tip of the Coromandel Peninsula. Both teal species were a lot less brash than the arrogant mallard, and kept much further away from human activity. The brown teal was particularly wary, and I never obtained a decent close-up image of him.
For a time during mid-summer I seemed to spot some interesting new bird species every second time I went down to the stopbank with my camera. Wading birds took refuge in the wetland when the harbour mudflats where they fed were immersed by the incoming tide. A bar-tailed godwit was a regular sight for a time, as were up to a half dozen wrybills, and sometimes there was a banded dotterel or two. Pied oystercatchers first came to the old paddocks just to rest, but after a time they discovered they were roosting in a tuck shop and I have since seen them gorging themselves. A much more unusual species came and went over a period of weeks around February—a pectoral sandpiper, one of the rarest migratory waders to reach New Zealand’s shores. It was over 20 years since I’d sighted one of these little waders in the Bay of Plenty.
That so many birds were nesting successfully was obvious to anyone using the walkway along the stop‑bank, and people began to take an interest in what was happening. Time after time as I sat with my camera and long lens, passers-by would stop to talk about the bird life, tell me what they had seen on days when I hadn’t been there, and ask what unusual birds were to be seen that day. I managed to get good photographs of most of the rarer species and wrote regularly about them for the local paper. Originally a focus of widespread disdain, the flooded paddocks now aroused people’s curiosity and attracted bird watchers from around the district.
In the 20 months or so since the floodgate was removed, there has been much change. The expanses of bare mud are beginning to disappear under large patches of bachelor’s button (Cotula coronopifolia), a plant which, before the sea was let in, the grazing cattle had kept down. Its yellow flowers first began to brighten the new wetland in tiny patches in the early spring of 2005, and by late autumn wide areas were carpeted with them. Mangrove seedlings have spread as far through the paddocks as the tide can reach. As for the decrepit fences, their panels of wire and rotting battens are being rolled up and carried off. Eventually, John Holwerda intends bringing in earth-moving machinery to dig extensive ponds in the more elevated areas, and plant wetland trees and shrubs. As the habitat is improved in this way, even more native birds will be able to live and breed in safety just a few hundred metres from the centre of town.
With the start of this year’s shooting season, on the first Saturday in May came the expected influx of ducks. Paradise shelduck and mallard numbers increased considerably, until these birds were the most abundant in the wetland. The stilts, previously the most numerous, dispersed in late summer to favoured wintering grounds further north.
It will be interesting to follow the changes that overtake this little wetland in the next few years. New plants will establish, the areas of bare mud will shrink, and the bird population will undergo further changes in composition and number. And maybe the success of John’s brave initiative might inspire a few other landowners to follow suit.