Displaying items by tag: Bittern
It’s not all boom and gloom
It’s autumn and we’re hunting for Australasian bitterns – but not in the thick raupo or out in the shallow waters along wetland edges as you would expect.
No, we’re on farmland - the last place you would think to look for an endangered bird that is rarer than the kokako.
Yet this is where my telemetry gear tells me we need to go. A loud beep pulses out from the little box that hangs from my neck, and I know from the frequency that Prince Tui Teka is close.
It is hard to imagine Prince in this environment. His streaky dark-brown and beige plumage contrasts markedly against this sea of emerald green - so that instead of blending perfectly into the raupo, as he does in his breeding territory at Lake Whatuma, he stands out like a gangly teenager with stage fright - or worse, a possum in the headlights.
We have long suspected that bitterns forage in farmland drains and small spring fed creeks. After all, this is where members of the public report seeing them. Yet bitterns are also easier to spot in these environments, and the habitat is far removed from what the species is reported to like. This is why these sightings have always seemed like fortuitous interactions rather than something of the norm.
The same can be said for bitterns leaving Lake Whatuma. We always thought it was possible, but somewhat unlikely. In the 1980s, a few bitterns carrying transmitters at Whangamarino wetland in the Waikato left their breeding site and were never re-found. Yet other bitterns marked in the same study were known to remain within the area. There are multiple reasons why we might lose the signal of a transmitter carried by a bittern and not all reasons relate to the bird leaving the area. For one, the thick raupo they live in has a high water content, and therefore dampens the radio-signals emitted by our transmitters. So if one has no idea where a bird has gone, and there’s a chance it is in thick raupo, thorough searches of the area are needed to be sure it has left.
So when the signals of all six of my marked bitterns suddenly disappeared in late December, and thorough searches at Lake Whatuma revealed nothing, I have to admit that I was a little surprised. One or two birds leaving the lake was expected, all of them leaving was not. At the same time it was also logical.
The departure of these birds coincided with a dramatic drop in water levels at Lake Whatuma. For most wetland birds this was a god-send – fish and other small prey items become concentrated in the centre of the lake where several wading birds, like pied stilts, congregate to feed in large numbers. But this is not good for bitterns. Of all the species in the heron family, bitterns are known to be the least behaviourally adaptable.They like what they like and that’s it. They’re not one of those gregarious flighty species that can opportunistically flit between people’s gardens, like the silver-eye. And they are not interested in probing around with yappy pied stilts. They’d much rather stalk and stab their food in peace - preferably somewhere that there’s cover and low water levels. If they can’t do that, they leave.
So they left.
Yet finding my birds in these areas also troubled me. Sometimes I would find my bitterns foraging happily on gambusia soup or an army of frogs with lots of cover around them. But more often than not I’d find them wandering along a deep drain looking lost and dispirited. There will have been a time when this happened with brown kiwi. When they were still on peoples doorsteps, being seen by locals who loved and adored them. Yet their habitat was still in decline. They were visible not because they were plentiful, but because they couldn’t find what they needed, and were out and about looking for it…and then one day they were gone.
I believe we’re at this unique position with bitterns. The birds are still around but don’t have everything they need for the population to increase. This is a concern because there will be multiple factors driving the decline of bitterns and many of these factors are still poorly understood. The longer a species remains endangered the harder it is to reverse the decline. If you need any more evidence to convince you of this, you only have to look at how intensive (and expensive) the kakapo recovery program is – a species that is currently only one threat classification rarer than bitterns.
The signal emitted from the transmitter carried by Prince Tui Teka gets stronger and suddenly he flies up out of a tiny raupo patch at the edge of a stream. I know that he saw us long before we saw him. As soon as we came over the brow of the hill he will have been tracking us – just as we were tracking him. He will have been standing in the raupo with his beak pointing towards the sky and only his eyes moving as he watched us across the paddock. He will have seen us pause several times to visually scan the raupo patch. The same patch he was hiding in. Who knows he may have seen us look right at him. Yet until this moment we had not spotted him, and even if we had his plumage makes him look exactly like all of the other raupo stems in the same patch.
He has only flushed now because he knows the game is up.Thanks to the transmitter he carries his camouflage no longer prevents us from re-finding him. I watch him land further down the stream before placing my boot in the water where he was previously standing – the stream is shallow and several small fish and amphibians dart away from me and disappear into the aquatic vegetation. This is one of the better places I’ve found him. There is some cover for him so that he can hide while he forages and the water is clear and shallow enough for him to see his prey. I leave him in peace and head off to find the landowner and congratulate them on this discovery. It’s not all boom and gloom – this landowner likes bitterns and has already said he will not remove any of the habitat Prince uses.
I still suspect Prince doesn’t have everything he needs but at least this site is better than the empty drain he was wandering along last week.Upon returning to my van on the top of the hill I have a quick listen for the bittern Tama Tomoana with my tracking gear. Members of the local hapu named this bittern after one of the grandsons of Henare Tomoana, a prominent Maori leader in the Hawke’s Bay region in the late 1800s.
Tama has been missing for seven months now. During the breeding season he was one of our most site-loyal birds and he was regularly found booming within a small area of less than 2 hectares in size - basically one small raupo patch. This was in contrast to some of the other bitterns, like Barry White, who boomed from lots of locations within a 15 hectare area.
This previous site-loyalty left us extra surprised when Tama disappeared and then could not be found. By now all of the other bitterns were accounted for – even Bing Crosby, who had originally flummoxed us last year by disappearing mid-way through the bittern breeding season. In late January we happily rediscovered Bing at Wanstead swamp, a site that’s about 15 kms from his breeding site. Of all of our wandering bittern, Bing was found the farthest from home. We looked for Tama in all of these areas too and nothing was heard.
Colleagues in Australia had recently attached a satellite transmitter to a juvenile male bittern and found that this bird moved farther than 550 kms after breeding had finished, crossing two state borders. Clearly our bitterns could physically move long distances if they want to - this got us thinking that perhaps Tama has done something similar? Five months after he went missing we decided we needed to broaden our search, so we put out a national plea asking anyone with access to telemetry gear to check their wetlands and listen for his signal. People looked for him at wetlands across the country - from Northland down to Waituna lagoon in Southland. His signal was still not found.
In June, all five of our autumn wanderers came back to Lake Whatuma. We waited with baited breath to see if Tama would also return - but his signal remained silent. By July 28, local landowner Max Lyver reported hearing the first bittern boom on the lake. The breeding season had begun, but still Tama was missing. We’d given up hope. Then on August 12, eight months after he’d left the lake, and over one month later than all the other marked male bitterns, Tama’s signal was once again heard beeping from his usual breeding territory. He was back and booming again. Where he went we will never know. He clearly still has a story to tell. This year we hope to recapture him so that we can replace his radio transmitter with a satellite transmitter - kindly donated by Ducks Unlimited, NZ. This will allow us to track him regardless of where he goes, meaning we will be able to get a complete story of his autumn adventures next year.
To me, Tama’s return to Lake Whatuma highlights just how much we’ve learned about the habits and behaviours of these birds over the 12 months they have been carrying transmitters – and yet how many mysteries still remain.
Without Ducks Unlimited, NZ’s continued financial support of this project we would not have been able to unlock these bittern secrets. Knowledge gained by this project is being used to help inform bittern conservation projects nationally.
Emma Williams
Australasian bittern/matuku
Bitterns are found throughout New Zealand - in the North Island they predominantly inhabit Northland, Waikato and East Coast wetlands; while in the South Island they mostly inhabit West Coast, Canterbury and Southland wetlands. The most important bittern site nationally is Whangamarino Wetland, a large and diverse wetland complex in the Waikato.
Bitterns are large, stocky birds, with streaky dark brown and beige plumage on their throat, breast, abdomen and thighs; and dark brown on the neck and back. The head is dark except for pale beige around the cheek, forming a pale eyebrow. Plumage can vary significantly and may be age related.
Bitterns are rarely sighted due to their exceptionally cryptic behaviour, inconspicuous plumage resulting in excellent camouflage and the inaccessibility of many wetlands. They are mostly active at dawn, dusk and throughout the night. Bitterns are occasionally spotted in the open along wetland edges, drains, flooded farmland and roadsides.
They are very sensitive to disturbance and will silently creep away to avoid detection, or adopt the infamous ‘freeze’ stance (with the bill pointing skyward) if approached. This allows bitterns to blend into many environments, whilst maintaining a close watch of surroundings. If an observer continues to advance on a bittern, then it will eventually take flight in a laborious manner.
Often the only sign of bittern presence in a wetland is the male’s distinctive booming call at the beginning of the breeding season. Each call sequence may consist of 1-10 individual booms, with an average of 3 booms. Boom sequences are repeated at regular intervals, and normally preceded with inhalations or gasps. Females are mostly silent, apart from producing an occasional ‘bubbling’ sound upon return to the nest, or a nasal ‘kau’ when alarmed. Bitterns in flight may produce a resonant ‘kau’ or ‘kau kau’.
The breeding season is extremely long, spread over a 10-month period. Females construct a reed platform nest amongst dense vegetation deep within wetlands.
A clutch of 3-6 eggs is produced between August and December (peaking in November), and then incubated solely by the female for 25 days. Chicks remain in the nest for 7 weeks and fledge from November to May. Bitterns are considered an indicator of wetland health, as they are dependent on the presence of high quality and ecologically diverse habitats, which are rich in food supplies (such as eels, fish, freshwater crayfish, aquatic insects, molluscs, worms, spiders, frogs and lizards).
Bittern numbers have declined drastically since the arrival of European settlers, with over 90 percent of freshwater wetlands now drained and cleared. Ongoing wetland degradation continues to be the chief threat, resulting in habitat modification and loss, reduced food availability and poor water quality. Other threats contributing to bittern declines include predation by introduced mammals (particularly cats, rats, dogs and mustelids), human disturbance of nesting bitterns, as well as power-line and vehicle collisions.
You can help bitterns by becoming involved in wetland conservation and reporting all sightings (or calls) to your local Department of Conservation office. Most importantly you can protect wetlands on your property by planting native vegitation to create riparian buffers and fencing waterways from livestock.
Sabrina Luecht
Wildlife Project Administrator
(supplied by The Isaac Conservation and Wildlife Trust)
Urban bittern chicks
Urban bittern chicks get into strife
Now, if I was to ask how many of you have seen a juvenile bittern or a bittern nest, I think it’d be safe to assume that most of you haven’t. And that’s saying a lot given that you are all wetland enthusiasts who regularly work and play in these kind of habitats.
So when we got a report that a female bittern chick had been found wandering along a road in Christchurch you can imagine our surprise. What was one of the most cryptic and secretive wetland birds doing on a road in the city? And the surprises didn’t end there – a few weeks later a second female bittern chick walked into a residential garage, only 500m from the location where the first bittern was found.
There had to be a nest nearby – but where?
Both bitterns were very skinny and clearly dehydrated. They were taken to bird rehabilitator Jackie Stevenson, who set about trying to fatten them up and get them feeding for themselves. In the meantime, local ornithologist Peter Langlands set about trying to find their nest.
Now this is no easy task. Bittern nests are tricky to find. A broody female bittern will build her nest by bending blades of raupo to form a floating platform that is perfectly hidden in the thick vegetation. And she’s not necessarily alone. Male bitterns can have multiple females, which all appear to nest within close proximity to each other.
Once a mother-to-be is happy with her nest she’ll lay between 3 and 5 eggs before starting to incubate. She hatches the eggs and rears the chicks alone, apparently chasing the male away if he tries to get too close. While incubating, she’s almost impossible to see as her streaked plumage blends perfectly in with the surrounding vegetation. Occasionally she’ll slip silently off the nest to feed, but only momentarily as this leaves her eggs vulnerable to predators.
After about 25 days, her eggs will hatch to produce little fluffy chicks with Albert Einstein inspired hairdo’s. These fuzz balls, emerge as masters of disguise straight from the eggs, and will adopt a perfect ‘freeze pose’ that looks similar to that of the adults if they are disturbed. Chicks fledge at about seven weeks old. However, there is some suggestion that they may start wandering from the nest as early as two weeks old - which is perhaps how one chick ended up on a city road and the other in a household garage.
Midway between the locations where these two birds were found lies Travis wetland, a 120 hectare swamp complex that has been restored over the last 15 years by the Travis wetland trust and the Christchurch council. It is the most likely place where these two birds came from. As it happens Travis is a noteworthy place, with an interesting history. In the 1960’s, this beautiful wetland was under threat from developers, who wanted to convert it to a residential area. Luckily, the locals had other ideas. They realised the importance of the site’s natural biodiversity, and argued long and hard for its protection. After a long battle that involved a petition signed by almost 7000 people, biodiversity won out, and in 1997 the site became a natural heritage park.
And lucky for bitterns that it did!
Since then, these two bitterns have done well in captivity and we were able to release them over the festive season - one along the Waimakariri river and the other at Harts Creeks. We attached radio transmitters to both bitterns, one of which was kindly funded by Ducks Unlimited. Both of these birds will be tracked regularly by local enthusiasts and, as female survival and breeding success is the secret to saving a species in decline, and these birds are the only females to carry transmitters at the moment - the information we gain will be essential for saving the species.
Emma Williams
And thanks to Gill Lundie for organising the school visit.
Project Bittern (Matuku) Report
Ducks Unlimited NZ AGM (23 July 2016)
Emma Williams has continued working on the bittern project assisted by me and other volunteers.
Key points are:
- Emma graduated with her Doctorate Degree at Massey University which was based on bittern research. A huge thank you to DU for helping fund a major part of her work to learn more about this iconic critically threatened species.
- A total of 10 male bitterns (six 2014 and four 2015) were captured at Lake Whatuma and transmitters attached. Of these 10 birds, nine left the lake over summer with one bird remaining on the lake. The bird that remained on the lake was found dead in late April in raupo and cause of death unknown. Four of the birds have returned to the lake in July and one other is being monitored at a wetland 10kms away. In spite of extensive searching the location of the remaining four birds is unknown, but it is most likely they will return to the lake in time for spring like birds did last year. The DU funded transmitters have contributed significantly to our much increased knowledge of this secretive bird.
- Emma travelled to Christchurch earlier this year to place transmitters on two bittern chicks that had been found abandoned not far from Travis wetland on the outskirts of Christchurch. These have been monitored by local people. One bird is still alive near the mouth of the Waimakariri River north of Christchurch and the other was found dead in mid May near the mouth of the Opihi River over 100kms south of Christchurch. This bird was examined and appeared to have died of starvation which is not uncommon overseas with bittern. Very interesting results plotting the movement of this juvenile bird and proves that bittern can move considerable distances.
- We held a very successful meeting on April 6 for the local Waipukurau community, landowners and Iwi to up-date them on the bittern project. Over 50 people attended and DU received well deserved acknowledgment for their significant contribution to the project.
- Emma has done no further school talks in the Wairarapa but will complete others this spring organised jointly between her and Gill Lundie. She has spoken to a number of schools in Hawke’s Bay. Emma continues to provide written articles for Flight.
- Bittern are a species under severe threat from wetland loss, predation, poor food supply and human disturbance. Population trends are negative. The Department of Conservation operate a conservation threat classification system of bittern and last month bittern were upgraded to the highest level of Nationally Critical Threatened Species. Kakapo and takahe share the same ranking which highlights the plight of this iconic wetland bird.
- It is important that DU continue to support the bittern conservation programme and encourage others (DOC, Forest & Bird) to commit to the preparation of a national bittern recovery plan.
- In 2015 DU Directors agreed to support the bittern project to the level of $25,000 to enable Emma Williams to continue her research work and purchase transmitters. Expenditure to date is (Emma Williams $7322) and (transmitters $9211.25). The remaining $8467 will be utilised this coming spring/summer.
John Cheyne
Coordinator Project Bittern (Matuku)
Bittern sanctuary
Northland farmer gets help with bittern sanctuary
Living Water - the Fonterra/Department of Conservation partnership – is helping Ian Lupton create a sanctuary for an endangered native bird on his Northland dairy farm.
When Ian bought his farm - eight kilometres north of Dargaville – he saw no native wildlife on the property. This changed after he reduced the amount of nitrogen fertiliser and chemical spray being applied on the farm.
“Within three years frogs, eels, pheasants, and herons were common daily sightings. I even began seeing bittern fishing for eels in a canal and drainage ditches on the farm,” said Ian.
Australasian Bitterns, or matuku, are endangered native birds that live in wetland areas. The brown, heron sized birds, are very shy and have excellent camouflage. They feed mainly at night, on fish, eels, frogs, freshwater crayfish or koura and aquatic insects.
“Regularly seeing bitterns on my farm gave me the idea of establishing a bittern sanctuary because a successful dairy farm and native wildlife can go hand in hand,” said Ian.
Living Water is a 10 year partnership between Fonterra and DOC working with dairy farmers, iwi, conservation groups, schools and other agencies in five key catchments in significant dairying regions. The focus is on increasing ecosystem resilience and farm profitability, which includes improving water quality and increasing the abundance and variety of native wildlife in the catchments. With help from Northland Regional Council, Ian sought funding from Living Water for his bittern project.
Fonterra North Island Project Manager Tim Brandenburg said “Ian’s dream of creating a sanctuary for bitterns fits perfectly with Living Water’s goal to increase the variety Safe place: A Bittern takes a stroll near wetland edge. Photos: supplied. and abundance of native wildlife in our catchments.
“The first step in building the sanctuary, is finding out how many bitterns are living on the farm,” said DOC Ranger, Olly Knox, who is co-ordinating the sanctuary work.
“Male bitterns make a booming sound, with each male making its own distinctive sequence of booms. Living Water funding will be used to buy digital recorders to record the bitterns booming on Ian’s farm. The recordings will be analysed to establish the number of bitterns on the property,” said Olly. The funding will enable Ian to control stoats and feral cats. These predators eat bittern eggs and chicks. It will also be used to control weeds that smother native plants and trees. Enabling native vegetation to flourish on the farm will increase the habitat for the bitterns.
Living Water is also providing native plants and grasses to go on the banks of the canal and drainage ditches on the farm. This will create more bittern habitat, which will encourage more breeding.
“Riparian planting also improves water quality by reducing the run off of sediment and nutrients into the canal and drainage ditches. And it provides habitat for the fish, eels, frogs and aquatic insects in the waterways. Having more of these freshwater species will increase the bittern’s food supply,” said Olly.
Dargaville High School has supplied native trees, flax and grasses for the riparian planting. Enviroschools Northland secondary schools facilitator, Jacque Knight worked with teacher, Tim Pratt to establish the nursery. Jacque has also involved Dargaville High students in the bittern project.
“The students are making monthly visits to the farm to record sightings of bitterns, noting details of the vegetation and conditions they favour,” said Jacque. “These are secretive birds. If we can learn more about the habitat and conditions they like, we can recreate these as we build the sanctuary.”
Local iwi, Te Roroa, is supporting the establishment of the sanctuary as it will enhance the local habitat and contribute to a healthy environment for the Matuku. Northland Regional Council Land management adviser, Pete Graham, is working with Ian Lupton to implement a Farm Water Quality Improvement Plan on the farm. “Creating the bitten sanctuary meshes really well with our water quality improvement plan. Pete said “The riparian planting improves water quality and creates habitat for bittern.” Living Water programme Living Water is a 10-year partnership between Fonterra and the Department of Conservation Wetland: Ian Lupton near his bittern sanctuary. (DOC) working with dairy farmers, iwi, conservation groups, schools and other agencies to improve the health of five key catchments in significant dairying regions throughout the country.
Living Water is working to increase ecosystem resilience and farm profitability, which includes improving water quality and increasing the abundance and variety of native wildlife in the five catchments.
To achieve this includes planting native trees, shrubs and grasses along waterways. This reduces sediment and nutrient run-off into the waterways. Animal predators and weeds are also being controlled, enabling native wildlife and plants to thrive.
Living Water catchments are:
- Kaipara Harbour - Northland - focusing on Hikurangi catchment north of Whangarei.
- Firth of Thames / Tikapa Moana - Hauraki Gulf - and Pukorokoro / Miranda catchment.
- Waikato peat lakes - focusing on lakes Areare,Ruatuna and Rotomanuka.
- Te Waihora / Lake Ellesmere - Canterbury – focus is the Ararira/LII catchment.
- Awarua -Waituna - Southland - focusing on Waituna catchment.
About Fonterra
Fonterra is a global leader in dairy nutrition and is a market leader with our own consumer dairy brands in Australia/New Zealand, Asia/ Africa, Middle East and Latin America. The farmer-owned NZ co-operative is the largest processor of milk in the world, producing more than two million tonnes of dairy ingredients, value added dairy ingredients, specialty ingredients and consumer products every year. Fonterra is one of the largest investors in dairy based research and innovation in the world. Staff work across the dairy spectrum from advising farmers on sustainable farming and milk production, to ensuring we live up to exacting quality standards.
BirdsNZ members brave the weather
The weather was not wonderful, but Robin and Heather List are seasoned birders and the pair set off to Wario to check on birds and do a count.
Robin said “The expedition consisted of Heather and me. We have the gear and do wetlands in squalls right cheerfully, so there was no grumbling in the ranks, though the waterproof notebook was abandoned in favour of the little recorder, which worked well under wet, windy conditions. The sun broke through at times and the whole place was looking grand as wetlands in winter can.
“There wasn’t a feather of a Dabchick nor yet a Bittern to be seen, so we’ll go looking in other haunts. It is possible they haven’t read the books and aren’t breeding yet, but it has been a mild winter.
“What we did see or hear in the space of 2 hours 10 minutes, not counting the walk along the road back to the car was, here in random order.”
Black swan 135,
Mallard X Grey 26, (possibly a couple of Shovellers among the tussocks at the sheds pond, but I think they prefer Boggy Pond)
- Teal 25,
- Yellowhammer15,
- Harrier 4,
- Blackbird 4,
- Welcome Swallow 6,
- Pukeko 6,
- Magpie 4,
- Kingfisher 3,
- Silver-eye 37,
- Goldfinch 15,
- Black Shag 1,
- Skylark 2,
- Spurwing Plover 5,
- Grey Warbler 1
All up16 species were seen by this intrepid pair, who also had an enjoyable lunch and excellent company in beautiful surroundings.
“Who could ask for more?” said Robin.
On the Scent - Bittern
listening posts – that was a lot of noise and a lot of birds. So many that observers regularly complained that they couldn’t keep track of them all.