Ducks Unlimited NZ

Displaying items by tag: Bittern

Thursday, 22 February 2018 20:50

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. 

Published in Issue 167
Friday, 16 February 2018 21:18

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:

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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)

Published in Issue 168
Tagged under
Wednesday, 07 February 2018 16:13

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. 

Published in Issue 169
Tagged under
Wednesday, 07 February 2018 14:32

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.

Published in Issue 169
Monday, 04 September 2017 23:58

On the Scent - Bittern

On the trail
It’s a beautiful morning on Lake Whatumā. As the last of the fog lifts and disperses, leaving the lake’s clear water exposed, Kimi and I float along the edge of the western shore quietly in our kayak. We’re looking for bittern nests and listening for the tell-tale bubbling call of chicks.
Nearby, peering out of two separate maimais are the heads of Finn McCool and Bernie Kelly. They’re watching careful for any signs of movement within the Raupo – an important job. Kimi and I can’t see more than a few metres in front of us as we move through the Raupo so we always need ‘spotters’ to detect the birds that are present but try to sneak away from us.
Suddenly, Kimi’s black Labrador nose begins to twitch. She’s picked up some scent. Her tail flicks up and begins to bounce from side to side as she reaches forward across the kayak. I slip off the kayak giving her permission to do the same. It is at this moment that we transform into our swamp alter egos. Kimi becomes an elegant torpedo - her otter-like tail propelling her beautifully through the water, until she silently disappears into the Raupo.
And me? Not so much.
My transformation is somewhat less fortuitous. Knee deep in mud, one foot already stuck and water up to my waist - my movements are best described as cloddish and ungainly. I slosh awkwardly after her trying my best not to sound like a heffalump bombing in a swimming pool. As I enter the Raupo, my radio crackles and Bernie announces that a bittern has flushed south of our location. We can never be sure of the sex of a bittern when we see one, but there are a few tell-tale signs that give us a clue.
Firstly, females are noticeably smaller than males, and secondly, in the case of Lake Whatuma, we know that none of the females are wearing radio-transmitters (yet!). Both Bernie and Finn carry radio-receivers. These devices detect the pulse-like signals emitted from any bird that’s been caught and still carries a Ducks Unlimited transmitter. If a radio-signal is detected, Finn and Bernie can identify the bird and follow its movements even if they can’t see it in the thick Raupo – so when a relatively small bittern flushes and they don’t get a signal on their receivers they know it’s likely to be a female.
The excitement in Bernie’s voice tells me this bird fits this criteria even before his words confirm it. Another female is great news. We’ve been searching bittern territories at Lake Whatuma for females and nests for a while now. We started unobtrusively by watching over known territories in October for something known as a ‘female foraging flight’. These flights are supposedly undertaken by females when they leave the nest to find food, a behaviour they have to do regularly because the males don’t feed them or the chicks. Such flights are noticeable and have enabled researchers to find nests overseas. By November, we have only witnessed a handful of these flights, and after investigating them further none suggested the presence of a nest. This surprised us. In previous years we’ve found nests by accident and all of them were (or would have been) at chick stage by November.
It was time to up the ante…and go in with the dog. Since November we’ve swept every known territory on foot looking for evidence of nesting. Up till now, and with the help of spotters like Bernie and Finn, we’ve been able to find at least four small unmarked birds (females), but none of them appear to show any interest in breeding. This latest bird would be the fifth. Bitterns are polygynous, meaning males often have more than one female. So it’s reasonable to expect up to five females to every male. To only find five on the whole lake – a site with at least twelve booming males – is somewhat concerning. If not down-right depressing.
To add to our concerns – the five males that still carry Ducks Unlimited transmitters at Lake Whatuma have been very unstable in their territories. They started off well, with all five returning to the lake in August to boom as usual and fight over the usual patches of real estate. Yet by October only two appeared to have claimed a Raupo patch. The others had spent all their time interfering with their neighbours before leaving to try elsewhere. Why are they not finding what they need at L. Whatuma?
So when Bernie confirms a fifth female. I think we can be forgiven for thinking we’d won the lottery. He immediately directs me southwards towards where the bird came up...but Kimi has different plans and starts heading northwards into the breeze. I pause for a second. On one hand I have a confirmed sighting to the south. A rare opportunity to reward the dog on fresh scent and a possibility that there was a nest nearby. On the other hand my dog clearly thinks she’s onto something better, and as I can’t be sure what the dog nose knows and John Cheyne is always telling me to ‘always trust your dog’…I decided to abandon the sterling advice of the spotter and follow Kimi’s lead.
I wasn’t disappointed. It took us awhile to find the four perfectly formed olive eggs that were tucked away on a carefully constructed platform in the thick Raupo. We think the nest belonged to the same bird that the spotter saw. Kimi has been trained on feathers and the live bird’s scent, and in this case the wind would have been wrong for her to detect the flushed female. Instead we suspect that the female moved south to evade us as we entered the Raupo. Kimi hit its scent track and was able to follow it back through the vegetation. It was definitely a team effort requiring all parties - the spotters, dog and handler.
Finding Nests
There are several reasons why we’re particularly interested in finding nests this season. We have little knowledge of how successful bitterns are in breeding and whether chicks survive to adulthood. Nests are notoriously difficult to find and this is part of our problem. To date we’ve had great success in developing methods for monitoring male bitterns (through their conspicuous booming call) but have no means for detecting females and chicks. Yet it’s the females and chicks that are our capacity to save the species. Just like money in the bank, the more we start with, the greater the capacity to grow our fund (or bittern population). One male can fertilise several females, so it’s the females that limit the size of our deposit. The more eggs she lays the higher the interest rate, and the more chicks that survive the greater the deposit in the following year.
…and of course to achieve this you have to prevent your significant other from hammering your credit card (prevent threats) in the meantime – this is tricky for bitterns as we’re still working out how many we’ve got, who’s hammering the bittern credit card and how much they’re spending…and there are so many potential spenders out there i.e. predators, poor water clarity, fluctuating water levels, poor food availability. We have many reasons to believe our bittern credit card is out of balance. In the last 12 months five starving nestlings have been found by members of the public right in the heart of urban areas – two females in Christchurch, and two males and a female in Tauranga - unusual behaviours for a secretive wetland specialist species. What happened to the parent that caused these birds to wander? Why were they nesting near to such accessible, high-disturbance areas in the first place? All five birds went into captive care and four survived to be released later in the year with healthy weights. We followed these birds post-release using Ducks Unlimited transmitters. To date two have died of starvation, one is missing – leaving a lone female surviving in Tauranga as our starting deposit.
Extinction Looms
As recently as 2010, surveyors at Whangamarino wetland – a site touted to be the national stronghold for bitterns – regularly recorded 50 + bittern calls within 15 minute long surveys. The number of birds calling could be as many as 12 individual birds per listening post and there were 40
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.
Sadly these days are gone. Now the same locations are eerily silent, and observers are lucky to find seven birds across the whole wetland. The Australasian bittern is no longer Nationally Endangered. It is now Nationally Critical - the same threat classification as Kakapo – and the last threat classification before Extinction. The clock ticks…all year around multiple threats hammered away at the bittern credit card…and once a year there’s a short opportunity for bitterns to make their deposits. …how much longer before the balance turns red?
Emma Williams
Published in Issue 170
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