Godwits in trouble on migration from New Zealand to breeding grounds in Alaska

Ecologist Rachel Hufton reports

Many shorebird populations are in serious decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands (attributed to land reclamation) in the Yellow Sea, which provide critical stop-over/ re-fuelling sites for shorebirds during migration is believed to be the cause of this alarming trend. The Yalu Jiang coastal wetland, a protected area in the north Yellow Sea, supports the largest known migratory staging population of bar-tailed godwits and great knot. Now, these shorebirds are further at risk as essential food resources such as bivalves and crustaceans are further under pressure due to a record cold weather period – the coldest in 69 years.

NZ Godwit
Godwits travel 17,000 km from the southern hemisphere to the north and back each each year

Bar-tailed godwits and red knots are currently looking their finest (in alternate plumage and full body weight) in preparation to leave New Zealand and begin migration north to their Alaskan breeding grounds. Most of New Zealands godwits have begun migration or have already arrived at the stop-over site in China at Yalu Jiang National Nature Reserve. Here a variety of shorebirds depend on the availability of abundant reserves of bivalves, crustaceans and polychaete worms to promote good body condition and breeding success. This year there are likely to be a lot of hungry shorebirds such as flocks of bar-tailed godwit (a IUCN Red List species) which might not complete their journey to Alaska to breed.


NZ Godwit
Bar-tailed godwits in alternate plumage with extra body fat to aid migration flight, Golden Bay wintering site, New Zealand

What Can Be Done

An ambitious plan to create a giant bird feeder kilometres long and wide, with farmed shellfish dropped over the mudflats to feed the birds and help them on their way to their breeding sites in good condition.

As well as helping the birds continue their life cycle this year, this work will also provide information about future mitigation/ compensation strategies for shorebirds. The mudflats of the Yellow Sea are being destroyed through reclamation and, increasingly more common extreme weather events.


Bar-tailed godwits getting ready to leave Miranda and fly to Alaska stopping off at Yalu Jiang Reserve

Immediate action is required to help contribute to funds already raised to feed the shorebirds at Yalu Jiang coastal wetland. The Pukorokoro Miranda Naturalist Trust (PMNT) is collecting donations in New Zealand to be transferred to the Hong Kong Birdwatching Society, a Birdlife International Partner.

Nelson Ecologist and Ornithologist David Melville is currently working in China and confirms that so far half the total funds required have been raised, but any further contributions would be much appreciated.

“We need to act fast as the seeding of clams has to take place on the spring tide series in Mid-April, or not at all.” He said (Radio NZ).


NZ red knot
Red knot in alternate plumage, feeding up before departing Golden Bay, NZ March 2017

This article highlights the importance of maintaining the quality of protected shorebird staging sites and other habitat, as important in shorebird conservation as is safeguarding of staging sites from land reclamation.

In New Zealand, pressure of pollution and coastal development are common and the outlook for shorebirds is a concern particularly for endemic species such as dotterel and wrybill as well as wintering Arctic migrants. However, the pressure here is on a reduced scale in comparison to the rate of habitat loss in the Yellow Sea – a global threat to shorebirds difficult to compensate.

Hope on the horizon

In January this year China announced it would dramatically curb reclamation of wetland for commercial development. A decision that can only have a positive impact on shorebird populations. Ongoing joined up international conservation efforts are essential for the future of endangered shorebirds.


NZ red knot
Red knot, Miranda wintering site 2016

Reference

Shou-Dong Zhang, Zhijun Ma, Chi-Yeung Choi, He-Bo Peng (2018). Persistent use of a shorebird staging site in the Yellow Sea despite severe declines in food resources implies a lack of alternatives. Bird Conservation International.

Rachel Hufton is a former shorebird guide of Pukorokoro Miranda Shorebird Centre (sister site of Yalu Jiang National Nature Reserve) and a founding member of the Aspiring Biodiversity Trust

Makarora Braided River – an under estimated biodiversity hotspot

Makarora braided river approaching the head of Lake Wanaka. BRaid (2017).

From the headwaters of the Makarora on the eastern flanks of the Southern Alps near the Haast Pass in Mt Aspiring National Park. The Makarora River flows south west and is joined by the Blue and the Young Rivers, then extending its braid plain further meeting its confluence with the Wilkin River before dissipating its energy into the head of Lake Wanaka.

Driving along the Wanaka Haast highway the Makarora braided river habitat is often overlooked or missed totally, yet the Makarora River is quite spectacular and is an important habitat for a number of important endemic New Zealand bird species and an array of other flora and fauna. A section of this captivating landscape can be seen in the video footage https://www.youtube.com/watch?v=g242GDSweiA produced by Braided River Aid (BRaid) on a frosty July morning. Braided rivers (defined by migrating, weaving channels of water between temporary islands of gravel) are iconic habitats unique to New Zealand encompassing an array of wildlife found nowhere else in the world.

There are a number of endemic bird species which depend on this habitat to complete their breeding cycle. During spring, braided river birds such as wrybill, black-fronted tern and black-billed gull can be seen returning to their breeding sites within the South Island.

The wrybill or ngutuparore is the only bird in the world that has a specialised bill which bends to the right, allowing it to feed beneath boulders and along the surface of the water on biofilm. This charismatic grey plover is nationally vulnerable relying on the unique braided river habitat to maintain its life cycle.


Adult wrybill nesting within braided riverbed (OSNZ courtesy of Dianne Parker).

Here the wrybill nests, lays eggs and rears chicks, its cryptic colouration blended effortlessly amongst the alluvial gravels of the riverbed. From January, onward wrybill flocks migrate north to their wintering grounds mainly in the Manakau and the Firth of Thames with smaller flocks elsewhere.

Juvenile wrybill at Miranda chenir shell bank (Firth of Thames) wintering site. Rachel Hufton

The black-fronted tern or tarapirohe, nationally endangered, is an attractive and highly distinctive bird in breeding plumage, slate grey contrasting with a black cap and bright orange bill and legs. Black-fronted terns also breed only on braided riverbeds of the eastern and southern South Island, from Marlborough to the Southland within small colonies and have now returned to Makarora. Their eggs and chicks are also well camouflaged against braided river gravels.


Black-fronted tern roost on a gravel island at Makarora. Rachel Hufton.

The black-billed gull or tarapuka is the most threatened gull species in the world. Though still relatively abundant, numbers of birds throughout the South Island have rapidly declined. The black-billed gull is more slender than the red-billed gull, with a longer bill and nests in colonies mainly on sparsely vegetated gravel riverbeds.


Black-billed gull colony on the Makarora braided river. Rachel Hufton.

Other braided river birds present on the Makarora include banded dotterel and South Island pied oystercatcher. The banded dotterel is the most common small plover of New Zealand coasts, estuaries and riverbeds but is nationally vulnerable. Banded dotterel breed within the braided river habitat but also use other habitats for nesting. Often seen running along the waters edge whilst foraging for invertebrates.

The South Island pied oystercatcher is the most abundant oystercatcher in New Zealand but is declining nationally. Pairs of South Island oystercatchers are often seen breeding in braided river beds but also within adjacent farmland. The conspicuous black and white plumage, distinct call and long red bill make this a familiar species.

Braided rivers are dynamic habitats, and as a result are threatened by a wide range of factors. These include habitat loss due to hydroelectricity development, weed encroachment of braided river breeding habitat, and recreational use of rivers. But the most significant impact is predation by introduced mammals.Black-fronted tern’s, wrybill’s and their nests are preyed on by rats, stoats, ferrets, ferral cats and hedgehogs. In addition, predation by southern black-backed gulls and Australasian swamp harriers, both of which have become more numerous following changes in landuse.

Considerable conservation management efforts have been made on some New Zealand braided river habitats, predominantly in the McKenzie Basin region and Canterbury which have positively contributed to braided river bird populations. This is evident in the Tasman Delta where Kaki black stilt have been reintroduced. A now rare species, once historically found throughout the South Island braided rivers.

The Makarora braided river requires collaborative effort to help restore, maintain and promote these specialised braided river birds to flourish for future generations worldwide. This can in part be achieved through advocacy and awareness raising. A recent braided river biodiversity and conservation workshop delivered at Makarora by a local ecologist, was a great way for students to connect with nature whilst learning about braided rivers.

Students and staff from Makarora located school camp following interactive workshop on braided river biodiversity, conservation and river safety (Andrew Shepherd).

Makarora braided river birds need help to successfully fledge their chicks this year without being subject to invasive mammalian predation from stoats, rats and hedgehogs. Any donations towards invasive mammalian trapping efforts on the Makarora braided river will be gratefully received by the threatened bird species that are beginning to nest. Donations or the sponsoring of traps can be made through the Southern Light website. With thanks.

Wrybill chick (OSNZ courtesy of Craig Mckenzie).

 

References

BRaid (2017) Drone video footage. Makarora and Wilkin River.

Hauer, RF. & Locke, H et al (2016). Gravel bed river floodplains are the ecological nexus of glaciated mountain landscapes. Applied Ecology. Vol 2, No 6.

nzbirdsonline.org.nz

Peat, N. Patrick, B Rebergen, A. (2016). Rivers Rare. The first 25 Years of Project River Recovery (1991 – 2016). Department of Conservation, Wellington, New Zealand.

Wittington, RJ. (2015). The foraging ecology of non-breeding wrybills (Anarhynchus frontalis) in the Firth of Thames: a thesis presented in part fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University, Palmerston North, New Zealand.

 

Further information contact Ecologist: Rachel

 

World’s rarest wading bird the kakī / black stilt gets new lease on life

Exciting News Today – kakī New Zealand’s black stilt, has been granted funds to help secure the population status of the worlds rarest wader.

Black Stilts

Juvenile kakī following release at Tasman Delta, Nov 2016 (Photo by Rachel Hufton)

Finally, the Twizel Recovery Centre can begin to increase its capacity for hatching, rearing chicks and releasing juveniles back into their iconic braided river habitat.

I will always remember being part of one of the releases of juvenile kakī on the Tasman Delta with the DOC Twizel team – one of those special moments, indeed. A project well deserving of international support.

Rachel Hufton


Global Wildlife Conservation Partners in Future of New Zealand’s Kakī ~ For immediate release June 22, 2017

kakī / black stilt
photo credit Kate-Lawrence

Global Wildlife Conservation today injected some additional hope into the once-uncertain future of the world’s rarest wading bird, a critically endangered species found only on the South Island of New Zealand. In recent years, the kakī, or black stilt, has begun rebounding from the brink of extinction thanks to the New Zealand Department of Conservation’s captive breeding and reintroduction program. Through a significant contribution to the program, GWC is helping ensure that kakī can one day thrive on their own in the wild.

Adult Kakī with New Zealand’s highest mountain, Aoraki/Mount Cook
Adult kakī with New Zealand’s highest mountain, Aoraki/Mount Cook, in the background. (Photo by Liz Brown)

New Zealand is a true conservation jewel, but there are ongoing declines of native species and habitats”, said GWC board chairman Brian Sheth, who is visiting with the Department of Conservation this week and whose philanthropic organization, Sangreal Foundation, provided funds for the project. “We are excited to partner with the forward-thinking and collaborative Department of Conservation, who innovatively partner with non-profits, Māori communities, businesses, and other stakeholders to preserve the country’s unique natural and cultural heritage. The critical conservation program in the Mackenzie Basin, including the recovery of the kakī, will be a model for the country.”

pair of Kakī adults in the Tasman Valley
A pair of kakī adults in the Tasman Valley. (Photo by Liz Brown)

Kakī were once widespread across… [Read More at the Source>>]

Juvenile Black Stilt
Juvenile kakī (Photo Rachel Hufton)

Source: World’s Rarest Wading Bird Gets New Lease on Life

Saving the critically threatened southern New Zealand dotterel

Rachel Hufton of Illuminate Ecology, reports following a cannon netting bird banding trip at Awarua Bay, Invercargill, an important wintering site for the South Island New Zealand dotterel. A Nationally Critical Threatened Species of conservation concern.

South Island Dotterel

above: South Island dotterel with South Island pied oystercatcher and a bar-tailed godwit at high tide roost site, Awarua Bay, Invercargill

The New Zealand dotterel is an endemic shorebird which was once widespread throughout NZ until the late 19th Century. Since then it has seriously declined in range and numbers and is now found in two distinct breeding populations. The two sub-species were first recognised in 1994; the North Island dotterel Charadrius obscurus aquilonius (Nationally Vulnerable) and the South Island Dotterel Charadrius obscurus obscurus (Nationally Critical).

The northern dotterel is more numerous, found on or near to the coast (mainly on the shores of the Eastern North Island). The southern dotterel was widespread but now only breeds on Stewart Island wintering here at the coast or at Awarua Bay in Invercargill (a popular wintering site for shorebirds) feeding on intertidal mudflats. It is generally a larger bird, with a heavier build than the northern dotterel and tends to be darker in colouration. Biometric measurements for bird (e.g. mid-toe) and egg are also different.

South Island Dotterel

 


South Island Dotterel

above: South Island dotterel Awarau Bay in breeding plumage and returning to basic plumage – Photography credit for both above Glenda Rees

The breeding habitat of the New Zealand dotterel is the most defining difference between the two sub-species. The North Island dotterel nests within an impression on beaches where as the South Island dotterel is more terrestrial nesting in the herb rich hills of Stewart Island, above the tree-line.

The population of South Island dotterel sub-species was at its lowest 25 years ago at 62 birds. Since then, considerable efforts targeting pest control have increased the population. The current population is now around 153 individuals. This is a decline from previous recovered population of 290 in 2009 as a result of a targeted cat (feral) control regime. This was however no longer solely effective and the population fell to 126 birds in 2016. The population appears to fluctuate and a slight increase is to be treated with caution as these birds are potentially at risk of extinction, especially in relation to further threats now identified by the NZ Dept. of Conservation (DOC) (highlighted below).

DOC Trail cameras installed at nest sites on Stewart Island have identified further threats to this critically vulnerable species such as the Australasian harrier, spur-wing plover and white-tailed deer, which have been observed taking eggs from nest sites. Accumulative threats have also resulted in a sex ratio imbalance, as males have been found to incubate eggs at night and therefore more susceptible to predation.

In light of historical population trends, DOC are now actively developing further conservation action planning for the South Island sub-species. This forms a ramp up on invasive predator control including new toxin targeted at cats, rat control, variety of kill traps and control of other predator species such as spur-winged plover. There will be active nest surveillance, cameras installed and field monitoring rangers. Further birds will also be colour banded to help monitor adult survival, abundance, site fidelity and to screen for disease such as avian malaria.

This work has started, and on 6 June 2017 additional South Island dotterels were captured at one of their wintering sites, Awarua Bay, Invercargill by a OSNZ cannon netting team working alongside DOC Invercargill. Below shows the cannon netting site set up where birds roost during high tide.

South Island Dotterel Cannon netting

above: Cannon netting site at Awarua Bay, Invercargill at low tide.

All birds (adults and juveniles) were colour banded, processed and screened to help provide a better understanding, aid monitoring and guide conservation management of this species. Colour bands provide a unique identification code and allow birds to be identified and monitored more easily in the field (*no birds were injured or harmed during cannon netting).

South Island Dotterel

above: Adult South Island dotterel with unique colour band identification. Note: wide bill, large eye and pale legs. High tide roost site in the background with bird observation optics

This article highlights the importance of species population monitoring to guide effective conservation management. With concentrated efforts in place from a broad alliance of conservationists, there is hope of saving this endemic New Zealand shorebird for future generations.

References
Images by Rachel Hufton and where stated Glenda Rees.

Carter, K (2017). Saving the Southern New Zealand Dotterel. Department of Conservation. Stewart Island. Presentation given at the OSNZ Conference Te Anau, June 2017.

Dowding, J, E (1994). Morphometrics and Ecology of the New Zealand Dotterel Charadrius obscurus with a description of a new sub-species. Notornis. Vol 1. Part 4.

http://nzbirdsonline.org.nz/species/new-zealand-dotterel

Black petrels (Taiko) return to Great Barrier Island (Aotea) natal colony ~ Rachel Hufton, Ecologist reports…

above: A male black petrel with attendant very strong bill and scratchy nails ~ photo Rachel Hufton
Male Black Petrel
above: A male black petrel with attendant very strong bill and scratchy nails ~ photo Rachel Hufton

Mt   Hobson   (Hirakimata) on Great  Barrier Island  at   621m,   is home to the largest breeding colony of black   petrel   (Taiko)   Procellaria  parkinsoni.

The  geologically and ecologically captivating slopes of Mt Hobson comprise semi-mature forest with remnants of ancient and precious  conifer forest.  The woodland assemblage combines endemics such as totara, rimu, kirks pine, and kauri. Diurnally the mountain is audibly dominated by the prehistoric raucous call of kaka, coupled with contrasting melodic tones of the grey warbler.

As dusk turns to night the summit of Mt  Hobson […] Read the whole article here >>