Wrybill (Ngutuparore) For Bird Of The Year

There is a strong case for Wrybill Anarhynchus frontalis as Bird Of The Year.

The wrybill is an incredible bird with considerable resilience that enables it to survive and breed within the harsh, exposed and dynamic environment of New Zealand’s braided rivers. This unique species then migrates to the food-rich tidal flats of the North Island where flocks of wrybill congregate for the winter. Both sites instrumental to the survival of this species exhibit considerable threats (invasive mammal and avian predation, damage and disturbance of nest sites from recreation, declines in water quality, avian botulism, flooding of nest sites, climate change increasing severity of flood events, loss of habitat and lack of awareness at breeding sites) to survival rates which accumatively contribute to an overall population decline.

Vulnerable nest site of the cryptic wrybill, two blue-grey eggs within a hollow of braided river gravels (centre of image during incubation swap over). An area often used by vehicles on the Makarora.

Currently the wrybill is listed as Vulnerable under New Zealand and International Union for the Conservation of Nature (IUCN) Threat Classification, however should this species be re-evaluated and its threat status increased?

Currently the global population is estimated at around 4,500 – 5000 individuals but how current is this figure and does it take into account the current threat status. The last published demographic figures are based from 1999 Trend justification.

IUCN Trend Justification: Analysis of wintering flocks indicates a slow decline over the last 40 years (Veitch and Habraken 1999), which is supported by preliminary results from a long-term demographic study (J. E. Dowding in litt. 1999).

The wrybill is the only bird in the world with a laterally curved bill (always curved to the right) which allows it to feed on aquatic insects around the edges of rocks and crevices and also from aquatic biofilms. It relies on cryptic adaptation upon its braided river breeding habitat to avoid predation from invasive mammals and avian predators such as Southern black-backed gull. The wrybill’s neck is able to tilt upwards to the side enabling awareness of preadators from above but also downwards when foraging for invertebrate prey. Typically they lay two blueish-grey eggs within a hollow amongst riverbed gravels (as above image) and incubation is for a period of 30 days.

The characteristic call of the wrybill is integral to the onset of spring on New Zealand’s braided rivers.

Wrybill female at nest site battling sandstorm conditions on the Makarora River

Please vote WRYBILL For Bird Of The Year 2019 along with Pūkorokoro  Miranda Shorebird Centre and Braided River Aid (BRaid).

With thanks 🙂

Rachel Hufton is an ecologist and ornithologist fortunate to have experience of monitoring wrybill at both their wintering (Firth of Thames) and (more recently) braided river breeding sites.

Update: Two days after this article the nest site was washed away by rising flood water due to snow melt and rainfall. Both adults remained at the nest site, showing sign of distress searching for their nearly hatched chicks. Further highlighting the need to raise the profile of this endangered shorebird.

Male wrybill (female close by) looking for the nest recently (8 November) lost to the rising waters of the Makarora River. Eggs would have been due to hatch about now after 30 day incubation.

Spring in the Makarora Catchment – From Ridge to River

Coffee break at Jumboland airstrip (the Coru Lounge)

With this seasons work programme in full swing, spring 2019 marks the installation of ABT’s upper river predator control for whio or blue duck (Hymenolaimus malacorhynchos) protection within the Siberia Valley and the Wilkin Valley. This follows previous walkover survey work with the aid of a protected species dog specifically trained in the detection of whio; New Zealand’s ancient waterfowl species, an important part of Makarora’s indigenous tonga.

A whio pair (also known as blue duck) recorded within the Wilkin Valley Feb 2019

Here remnant populations of whio still remain however numbers are low and fledgling survival is limited by the presence of invasive predators such as stoat and rat. This can often lead to a sex ratio imbalance as females tend to be more vulnerable when nesting and during moult. The new trapping networks join up with alpine trap lines to help extend invasive predator coverage for this globally endangered species.

Predator control traps delivered by Backcountry Helicopters into mid-Siberia Valley. Photo credit Pilot Blair

Spring is also the time to resume alpine predator control operations for rock wren and kea protection. New traps added and a number of stoats, and rodents had been caught over the winter months despite not all traps being accessible at higher levels due to the amount of snow still present (these traps will be serviced next visit).

Invasive mammal trap exposed from the snow at Upper Lucidus (September 2019).
A mummified stoat caught at altitude during the winter months

Rock wren pairs were active at the Crucible Basin but all was quite in the upper Wilkin Valley (where snow cover heavier) suggesting that this population may not of yet stired from their winter torpor. Kea were heard calling above the Siberia Valley  and one in the upper Wilkin.

Crucible Basin trap drop off with Backcountry Helicopters and logistical planning for the day ahead
Snow cover along the ridge of Lake Crucible looking towards Gillespie Saddle (Oct 2019). The characteristic call of the rock wren is often heard here.

Back in the lower river valleys of the Makarora and Wilkin, braided river birds have returned and are starting to nest again. ABT braided river invasive mammal predator control continues on a monthly basis throughout the year with the help of regular volunteers. Stoats, rats, hedgehogs and feral cats are being reduced to help improve fledgling success of endangered birds such as black-fronted tern, wrybill and black-billed gull. The Southern black-backed gull is a avian predator of endangered braided river birds and their chicks. Adaptive management of this species is due to progress this season also.

Makarora braided river habitat showing the Wilkin confluence and the head of Lake Wanaka

Acknowledgements

With thanks to all our volunteers, funders, partners and supporters 🙂

Alpine predator control progress – winter activity indicated

Since the installation of ABT’s alpine predator control programme for the protection of rock wren Xenicus gilviventri, stoats have been recorded in traps at 1200 m elevation (refer to spatial distribution map below) in areas of rock wren habitat and they are still being caught during the winter months.

Adult male stoat caught at 1200 m by DOC 150 (kea proof) trap.

During this winter, Celium remote monitoring technology has shows that invasive mammalian predators are still on the move during the winter and are being caught within the alpine environment where indicative rock wren territories have been identified.

Snap shot of ABT trapping data Feb – April 2019 for Castallia/ Lucidus

The real time data shows current available trap coverage at Lucidus/ Castalia on 8 August 2019 is mostly reduced at lower altitudes and representing a threat to rock wren territory (southern scree area above Lake Lucidus). The red symbols display trap triggers and the green symbols identify the remaining trap coverage available to passing predators. The data illustrate that there is currently no imperative to replace bait (probably due to low temperatures in the alpine environment or lack of predator food source), and that servicing requirements are only determined by available un-sprung trap coverage at this stage (potentially effective rock wren protection).

Real time data provided by Celium remote monitoring technology.

The Celium remote technology provides additional information on alpine predators such as commuting activity and time of capture. Most trap triggers appear to occur at dawn between 06:00 – 08:00 h at 1000 to 1200 metres.

Time and altitude of invasive mammal trap triggers and previous trap servicing occasions

Climate conditions are recorded showing decreasing daily temperatures towards winter at all three Hub Stations. Overall winter conditions are cooler at Castallia/ Lucidus relative to the Crucible Basin.

Celium Hub Station daily temperatures at three alpine locations.

We look forward to servicing alpine traps and resuming rock wren monitoring this coming season, once baseline temperatures have warmed up and the rock wren are out of their winter torpor. Hope to see this juvenile from last year!

Last years (2018/2019) rock wren fledgling

Acknowledgements

With thanks to all our volunteers, partners and the following funders; WWF, the Tindall Foundation, Otago Regional Council, Oceana Gold and the Otago Community Trust.

References

O’Donnell, C F J, Weston K A, Monks J A. (2017). Impacts of introduced mammalian predators on New Zealand alpine fauna. New Zealand Journal of Ecology 41: 01-22.

Weston, K A, O’Donnell C F J, van Dam-Bates P, Monks J M (2018). Control of invasive predators improves breeding success of an endangered alpine passerine. International Journal of Avian Science. Vol 160, Issue 4.

Updating Whio/ blue duck records for the upper river catchments of the Makarora

One of ABT’s core purpose is the collation and updating of threatened species records within the Makarora Catchment to help facilitate and inform appropriate application of invasive predator control.

ABT have been updating records for whio/ blue duck Hymenolaimus malacorhynchos to help ascertain the current status of this ancient endemic waterfowl species within the upper reaches of the Makarora Catchment. No formal inventory has been completed for this species since the work of the late Peter Child during 1970’s/1980’s.

To date a specialist contractor Paul van Klink and his protected species survey dog (Hoki) has been commissioned to undertake walkover surveys for the upper Wilkin, the Siberia and the Young Valley.

Whio surveyor with protected species survey dog in the North Wilkin Valley

From the results of these walkover surveys and the addition of recent incidental records it is promising to see that there remains a remnant population. Numbers are low and in some cases are limited to just male individuals, a high prevalence of unpaired males on rivers without predator control is often common as nesting females are more vulnerable to mammalian predation. However, evidence of breeding success has been recorded with observations of pair bonds and a fledgling bird.

Adult male whio

This valuable survey work continues to expand for the region with the future aim of restoring viable, sustainable populations of whio/ blue duck within the upper river catchments of the Makarora for future generations.

Down stream of Lake Lucidus, North branch of the Wilkin with Hoki
Whio survey dog in action (Hoki). Image credit P van Klink

Reference

Child P, (1981). Birdlife of Mount Aspiring National Park. Scientific Services No.4. Department of Lands and Survey. Head Office, Wellington, New Zealand.

Celium Remote Monitoring Aiding Alpine Predator Control

The start of 2019 marks the installation of Celium remote monitoring technology for two key alpine rock wren sites within the Makarora Catchment. We are delighted to be partnering with Encounter Solutions on this innovative approach not yet trialled within the alpine environment.

Rachel Hufton with Celium Hub Base Station
Celium remote monitoring Hub at the head of the Wilkin River with Rachel to the left

The Celium platform is a low powered wireless network designed for the purpose of wide-scale rugged management applications. Celium consists of a range of communication devices called Nodes (attached to traps) equipped with sensors. The sensors are designed to monitor parameters such as the status of a pest control trap (below), which the nodes then communicate to the base station called a Hub. The Celium Hub transmits the data via satellite to the Celium cloud programme, which then sends a signal to the user via  a notification email or text message.

Trap node installed on side of DOC 200 (kea proof) invasive mammal trap

The Celium Platform can be used for predator control monitoring and also has potential application for monitoring climate/weather and wildlife. On this instance the installation intends to aid trap maintenance servicing efficiency for rock wren protection within remote areas.

Anthony with Simon (Encounter Solutions) checking that trap Node is communicating to the Repeater Hub via android software.

Encounter Solutions Director Simon Croft (below) enjoyed his time out in the field with ABT and gained a number of close encounters with New Zealands only true alpine specialist – the endangered rock wren. His technical knowledge was a valuable addition during the North Wilkin installation.

Simon from Encounter Solutions installing Celium Hub with ABT

Since installation there have been three invasive mammal trap triggers at the highest trap location points. We look forward to reporting back on what predators have been captured. More soon….

juvenile rock wren
One of this years juvenile rock wren (Makarora Feb 2019)

With thanks to sponsors; Otago Community Trust, WWF, the Tindall Foundation, Otago Regional Council and Oceana Gold.

Alpine predator control for the endangered rock wren Xenicus gilviventris

Rock wren protection installation

Classified as nationally endangered, the rock wren (Xenicus gilviventris) is New Zealand’s only true alpine specialist remaining in the mountains above the treeline for most of its life.  Following the results of ABT’s rock wren survey transect monitoring during Jan/Feb 2018 the team have been installing invasive mammal predator control within two key focal alpine areas. Areas include, the Crucible basin within the Siberia Valley and the upper Lucidus/ Lake Castalia, North Branch of the Wilkin.

Approach to upper Lucidus/ Castalia to deploy invasive mammal traps. Pilot Blair Backcountry Helicopters and Ecologist Rachel Hufton.

Invasive mammalian predator traps (DOC 200 and 150 models) were transported in to both sites on a suspended sling from a Hughes 500 helicopter. The traps were then distributed to designated locations extending and complementing existing predator control efforts within the locality.

Crucible basin rock wren protection deployment with Makarora’s Backcountry Helicopters

Site locations within the Makarora Catchment can be seen from the topograph image below. The North branch of the Wilkin and the Crucible basin are situated to the west of the Makarora River.

Population status

Rock wren are at risk from invasive mammalian predation particularly from stoats and rats but also mice. There is increasing recognition that invasive predators are widespread within New Zealand alpine zones. Recent work has found that humane kill trapping of invasive predators can increase rock wren breeding success within the alpine environment (Weston et al 2018).

The national population of rock wren is currently unknown but thought to be around 5,000 mature individuals (IUCN) with severely fragmented populations due to particular habitat requirements. The rock wren belongs to a unique ancient lineage of eight New Zealand wrens now only two species survive. The alpine rock wren and the rifleman Acanthisitta chloris, generally a forest passserine.

Male rock wren upper Lucidus/ Castallia

During both trips it was encouraging to observe a number of adult rock wren present busy foraging on invertebrate prey. Particularly, at Crucible basin following the late November snowfall. Most birds were male which may indicate females occupied on their nest sites.

Remote trap monitoring

With the aim of optimising alpine trap servicing efficiency and improving understanding of temporal and climate influences on predator trapping ABT have partnered with Encounter Solutions Ltd to install remote trap monitoring technology. The equipment will be installed in January for both alpine sites. This system has been applied to other trapping habitats but will be a first for the alpine environment.  If successful other remote rock wren habitats could benefit from use of this technology to aid predator control programmes.

Rock wren protection installation at Crucible Basin, Andrew Shepherd helping to distribute kea proof traps.
ABT’s Anthony Coote securing and geo-referencing mammalian predator traps at Lake Castalia.

Future populations

With dedicated effort it is possible that focused rock wren recovery at these sites could result in potential “source” populations of rock wren and expansion/ migration of numbers/ pairs into unoccupied habitat (Weston 2014).

With thanks to Otago Community TrustOtago Regional Council, Oceana Gold, Backcountry Helicopters Ltd, Tony Zimmerman trap supplies, Central Otago Hunting and Fishing, DOC Wanaka, Backcountry Saddles Expeditions, volunteers Nick Beckwith and Andrew Shepherd.

References

Aspiring Biodiversity Trust (2018). Alpine predator control plan for rock wren. Makarora Catchment Threatened Species Plan.

IUCN Red List of threatened species

Weston K.A. 2014. Conservation genetics of alpine rock wren (Xenicus gilviventris). Doctorate thesis.

Weston K.A., O’Donnell C.F.J., Van Dam Bates P. & Monks J.M. 2018. Control of invasive predators improves breeding success of an endangered alpine passerine.

Male rock wren Crucible Basin (Nov 2018).

Makarora Braided River Birds – Spring/ Summer 2018

The 2018 braided river bird survey for the Makarora River commenced on the 18 October over a period of three days. The survey area begins at Boiler Flat, includes the lower Willkin and finishes at the Makarora delta where the river meets Lake Wanaka. Endangered braided river birds; wrybill, black-fronted tern, black-billed gull, banded dotterel and South Island pied oyster catcher have returned to breed on the braided river again.

This years survey found six pairs of endemic wrybill (the only bird in the world with a bill that bends to the right) two on nests with eggs and one with two new chicks. During the survey one of the male wrybills was identified with a metal leg band and its unique code was identified thanks to the help of an amazing photo taken by volunteer surveyor Nick Beckwith.

Male wrybill (6+ years old) with metal leg band (right tibia) photo credit Nick Beckwith

The wrybill was originally banded as a juvenile at Miranda (Firth of Thames) and now as a six year old is found breeding over 900 km away. This bird has probably made the return journey at least five times. A wrybill female was also recorded with a metal band last year and she was found to have  been banded on the same day as the male (as an adult) at Miranda during November 2012.

Makarora braided river habitat and wrybill migration route (bottom left) from wintering site in the north island to breeding site in the South.
New Zealand Bird Banding Scheme Record

Key nest site monitoring is ongoing throughout the breeding season. Two wrybill chicks hatched on 6 Nov after 30 day incubation period; mainly by the female.

Female wrybill with two eggs

The black fronted terns had formed a number of nesting colonies with eggs at many nest sites along the length of the river. Unfortunately most nests have been lost to high level flooding over the last weekend but signs of re-nesting has already been observed.

Adult black-fronted tern. Photo credit Nick Beckwith
Black-fronted tern nest site

Despite the Makarora River flooded “bank to bank” last Friday the adaptation of endemic braided river birds is such that a flightless braid island bound banded dotterel chick somehow survived an extreme natural weather event (image below). Nature never fails to amaze!

Immature banded dotterel (pre-fledgling)

Southern black-backed gull population control commenced this season on the Makarora River and also on a more national scale for Canterbury braided rivers. The numbers of SBBG’s have significantly increased on the Makarora River and on a national scale due primarily to changes in landuse. They are a known predator of braided river bird eggs and chicks, particularly in relation to black-fronted terns. This is evident from trial camera footage at several nesting sites. Invasive avian predator control complements the existing invasive mammal predator control programme for the Makarora River. Similar control measures over time have been shown to increase fledgling success for black fronted terns on the Tasman River.

Fig 1, below summarises this years braided river bird walkover survey.

Fig 1: Summary results of Makarora 2018 braided river bird walkover survey

Other interesting records include a  banded and flagged South Island pied oystercatcher. This bird was originally banded at Sand Island near Nelson Airport as an adult during January 2010. This is an interesting record as little is currently  know about the migrational movements of this species.

South Island pied oystercatcher age 8+ years (Makarora Braided River). Photo credit Nick Beckwith.

 

 

Winter Update

Video screen shot from ORC Eco Fund promotional video. Makarora River

In the news, ABT are delighted to feature in the latest Otago Regional Council (ORC) Eco Fund promotional video (above screenshot of the Makarora River with the Wilkin valley in the background) and were asked to supply threatened species survey images from last season (top left and top right below) which have been used to feature in the new promotional brochure. The video provides a short clip on a number of valuable environmental projects happening across Otago. There is nice drone footage of the Makarora braided river habitat. The video aims to encourage projects that protect and enhance the environment and the community.

Inside view of Otago Regional Council’s Eco Fund promotional brochure featuring images from ABT’s rock wren monitoring programme (top left and right)

Makarora Catchment Threatened Species Programmes

We may have been quite but behind the scenes ABT are busy implementing and progressing Makarora threatened species programmes for endemic braided river birds, rock wren, blue duck / whio and forest birds. This also includes biodiversity education an integral part of connecting people with nature.

Predator Control

Invasive mammalian catch effort on the Makarora braided river has removed a number of stoats, hedgehogs, rats and mice in preparation for the spring bird breeding season. Feral cats and the Southern black-backed gull (an avian predator of endemic braided river bird chicks) are also part of the braided river bird restoration programme and will be addressed this coming season. Volunteer help has been essential to this progress.

Winter invasive mammal trap maintenance on the Makarora River (frosty…)

More soon..

Makarora Braided River Bird Restoration

wrybillchickjpg
Wrybill chick Dec 2017

The implementation of ABT’s Makarora Braided River Bird Invasive Predator Control Strategy commenced this weekend (7-8 April). A team of amazing volunteers helped deploy a number of invasive mammal traps along 15 km of the Makarora River. Trap locations and deployment was informed by previous braided river bird monitoring undertaken during the 2017/2018 survey season and existing information on the movement of invasive mammalian predators (capable of decimating indigenous bird life) such as stoat, rat and hedgehog.

Makarora shallow river crossing – linking arm technique

Volunteers keen to help indigenous wildlife included local Makarora residents, members of Makarora School and nearby residents of Lake Hawea.

Sunday with a little rain and wind…
Makarora river ABT
The beginning of the weekend at Wharf Creek, Makarora River

The day began with loading up of traps on two boats, one a jet boat with an experienced captain Rod Elliott and partner Jos Mclean. Following a jet boat ride to the far side of the river, volunteers were loaded up with traps for particular designated areas and equipped with a GPS. Traps were then securely staked, marked with coloured triangles and numbered to aid future maintenance.

Makarora River
Makarora delta adjoining Lake Wanaka
Makarora School pupil marking invasive mammal trap numbers

Following a trap setting demonstration and health and safety talk, traps were baited and sett according to recognised best practice.

The installation and maintenance of the Makarora braided river trapping network aims to help control invasive mammalian predator numbers so that endangered braided river birds such as wrybill, black-fronted tern, banded dotterel and black-billed gull can nest and successfully raise their chicks without being predated. In the longer term a noticeable increase in braided river bird restoration is desired.

Further traps are to be deployed and monthly trap maintenance will be ongoing during the non-breeding season with more frequent checks during the bird nesting season (spring/summer). Volunteers welcome!

Acknowledgements

Thanks go to all our volunteers. ORC. Also, BRaid for DoC 200 trap supply and production, bait donations from Hawea Flat egg suppliers, discounted radios from Hunting and Fishing Central Otago, waratahs from DoC Wanaka and support from Wilkin River Jets and  Mt Albert Station.

Captain Rod, Makarora River