Black Petrels: Winner or Loser in the Conservation
On 27 October 2015, Sanford CEO Volker Kuntzsch addressed the Hauraki
Gulf Forum’s State of Our Gulf Seminar in Auckland. He opened with a
picture of himself holding a black petrel chick – inconceivable five
years ago when before the same audience, seabird scientist Matt Rayner
presented his grim assessment of the risk for black petrels from
fishing. The picture he painted then was one of a bird headed for
extinction and led us to found the Black Petrel Action Group. Kuntzsch
went on to offer to stop commercial fishing in the Hauraki Gulf, which
grabbed headlines nationally. But he also said he was glad the black
petrel population had stabilised – when in fact the evidence indicates a
long-term trend of decline.
This article summaries recent research on
black petrel (taiko) for 2014/15 and explores the indicators for long
term population decline, looks at the impact of cat predation, and
current efforts to reduce the deaths of black petrels through fishing.
Finally, we ask the critical question: what more should the Department
of Conservation (DOC) be doing to protect this iconic bird?
An average season but habitat literally
slipped away and there are worrying trends
This year GBIET secured $15,000 from Auckland Council for ongoing
research on taiko breeding site distribution and population, carried out
by taiko expert Elizabeth Bell and the team from Wildlife Management
International (WMIL). Bell has been working on Hirakimata (Mt. Hobson)
monitoring black petrels as they return, breed and fledge chicks since
1996. The team monitors burrows throughout a 35-hectare study area all
over this rugged terrain, banding chicks and adults, logging returning
juveniles and breeding birds.
Bell reports that breeding success (a
fledged chick) was 70% in the study burrows compared to an average of
74% since 1996 – a declining trend despite the number of burrows used
for breeding increasing this year. This finding is concerning as all
birds reaching the 3-4 year breeding age need to breed successfully for
more than 25 years to hold the population stable.
June 2014, a huge storm wiped out about 15 hectares of black petrel
habitat – visible now as massive slips on the SE face of Hirakimata.
Some new burrows were found in the study area and elsewhere as a result,
possibly dug by displaced birds trying to find a new home, and fights
arising over some burrows.
Fewer returned ‘chicks’ were caught
compared to last season despite two intensive search periods with
trained seabird dogs. Adult survival was higher than in the past, but
juvenile survival (for birds 2-5 years old) was much lower. Bell thinks
it’s likely that survival of chicks younger than two years is even
lower; many do not survive to return to the colony. Of the 2500 chicks
banded, only 204 have so far returned (others may have returned but not
Seabird specialists are concerned that the
population may “go off a cliff” as breeding age birds die (the oldest
recorded is 29 years) and the population is not sustained by returning
On Little Barrier (Hauturu), search teams
located 90 out of 97 burrows last monitored by researcher Mike Imber in
1997. Breeding occupancy in these burrows was 29.5% (compared to 40% in
1997) and another 13% had been taken over by Cook’s petrels. Twenty-five
acoustic devices across Hauturu resulted in 4,230 hours of recordings.
The incidence of taiko calls is low and tells us that Hauturu black
petrels are likewise not doing well. Hirakimata remains the most
*Massive slip on Hirakimata above the Mt
Heale hut. Photo: IslandStay
Getting around – are there black petrels in our back yards?
In early 2015, searches by Jo Sim and her seabird dogs Maddi and Rua
covered Glenfern Sanctuary, Windy Canyon, Maungapiko, Whangaparapara, Te
Ahumata, Coopers Castle and other areas. They detected active black
petrel burrows at all sites, but predators had been there first in many
cases. While reassuring to find birds away from the main colony, it was
very frustrating to see so much evidence of feral cat impacts. Dead
adult birds had wounds from claws or teeth and remains of fledging
chicks were found along tracks or outside burrows. Bell reports that
there was plenty of evidence of rat predation – eggshell fragments and
remains of chicks with rat teeth marks. Disused burrows were also seen,
suggesting taiko have been extirpated by rats and feral cats.
In “Bugger” (‘Weaving the Strands’ June
2015), Hauraki Gulf Forum Chair John Tregidga told the story of a chick
killed by a cat at Windy Canyon. WMIL host many such visitors, this year
including schools (Okiwi and Mulberry Grove), commercial fishing crews,
industry leaders, a Labour MP Jacinda Ardern and media. Coverage of the
visits was carried by TV3 and Maori TV news, the New Zealand Herald and
Professional Skipper magazine.
In mid-November, a large gathering at
Windy Canyon welcomed back the birds to Hirakimata. The airfares for
Southern Seabirds Solutions (SSS), NGOs and visiting fishers totalled
more than the $1,700 budget DOC had for cat control in the colony. The
visit was just after two adult birds were discovered killed by a cat.
Every breeding adult counts when there are 1200-1500 breeding pairs
left. Cats are the biggest terrestrial threat to taiko, so the Trust
asked the Minister to urgently look at a solution to control cats in the
colony. Minister Barry’s response was disappointing – no funding for cat
control this year from DOC – and contained some flawed interpretations
of the threat.
*Feral cat predated black petrel on
Hirakimata. Photo: Biz Bell
Bell feels she was misquoted in the
Minister’s response, which focused on the few cat predation events in
the study area, and the low cat catch-rate. DOC may think it is doing
enough and traps on the colony are not needed, but the data on which
this thinking is based only includes Bell’s study burrows. Elsewhere in
her report, cat predation is detailed for other burrows. She told us:
“I’ve always said that cat trapping on Hirakimata should occur
pre-season (Sept-Oct) and pre-chick fledging (April-May) …this is the
most valuable use of funding and personnel time”. Bell will now create a
dedicated section on cat predation in her reports, highlighting the
recommendation she makes every year about continuing cat trapping at
Feral cats killing black petrels: the real story
Cat trapping began on Hirakimata in 2011/12 when four cats were caught.
Amelia Geary, the then Biodiversity Ranger on Great Barrier, set up
traps on tracks around the summits of Hirakimata and Mt Heale with
annual funding of around $4,000. In 2012/13 and 2014/15 no cats were
caught and in 2013/14, just one cat was caught – which does not
necessarily mean an absence of cats with factors at play such as
difficulty in keeping bait fresh (cats like fresh rabbit), other baits
used being less successful, and rats eating bait. Bell believes that
DOC’s trapping to protect pateke/brown teal in Okiwi (below Hirakimata)
has reduced cat numbers on the mountain. She believes feral cats from
Okiwi travel up the mountain at fledging time to target chicks before
they can fly. She supports the continuation of the Okiwi basin cat
trapping programme but not as a replacement for protecting taiko
breeding on Hirakimata.
How did DOC come to cease funding black petrel protection on GBI?
What we are seeing here are the consequences of current government
policy for a vulnerable species in a unique, nationally significant
ecosystem. We have a collaborative response from fishers, scientists,
iwi, NGOs and conservationists, a local DOC office trying to do the
right thing, and a community motivated to help. What could go wrong? The
answers, overwhelming numbers of cats and rats and diversion of DOC’s
Great Barrier biodiversity budget to “The Battle for the Birds” (1080
drops over South Island Beech Forests in 2015).
Hirakimata is a key biodiversity site for
the Aotea Conservation Park. However there’s something very wrong with
prioritisation at the regional level when it has no funding, manpower or
a volunteer programme for predator control. For this reason, GBIET had
already applied for funding to begin cat and rat control on Hirakimata
under a project called Friends of Hirakimata. A big hurdle for a
voluntary trust is the capability to manage the health and safety of
volunteers or employees. The opportunity for partnership is clear, but
DOC has not replaced the vacant partnerships officer role which could
make this happen. We understand that local staff understand the need
for, and preferred timing, of trapping and want to begin it again – but
budget must be found.
fishing practices continues to prevent black petrel deaths
On the positive side, Bell says it has been fantastic to involve the
fishing industry. Raising the profile of black petrels helps fishers
relate to what they see at sea. She is getting information directly from
fishers, including sightings of black petrels and the problems fishers
have with birds diving on baited hooks.
The effort going into changing fishing
practices is encouraging. In October 2014, this culminated in fishers,
NGOs, government, iwi and others pledging collaboration to help black
petrels and other sea-birds thrive alongside fishing in FMA1 (North Cape
to East Cape). The pledge includes measurable targets and milestones
that organisations report on annually. Three work streams back up the
pledge: commercial fishing, recreational fishing, and working with mana
whenua (Ngati Wai, Ngati Rehua and Ngati Manuhiri). Actions government
has taken include the appointment of two seabird liaison officers, roll
out of vessel specific seabird management plans, mitigation monitoring
and adherence checks, seabird training workshops and ongoing education.
We are still waiting on a measurement framework to demonstrate where in
the fleet this effort has been successful.
Southern Seabird Solutions (joint funded
by MPI, DOC, WWF and industry) continues to target recreational fishers
with the seabird smart message. This is challenging because there is
little knowledge of the extent of the problem, a huge range of fishing
methods, few known mitigation options, and a large, disparate sector.
Trustee Emma Cronin has been working for Forest & Bird in this area on
Aotea and boat ramp surveys continue via MPI.
It is incumbent on MPI and DOC to embed
actions to protect black petrels in fisheries management and annual
budgets. The next priority is to understand juvenile mortality when
taiko winter in the east Pacific, and to increase engagement with the
fishing fleets that operate there. Janice Molloy of SSS has been helping
MPI and DOC on this front but we await a specific, outcome focused plan.
Future moves for taiko conservation
Bell’s team are doing more GPS tracking of birds to determine where and
when they feed to understand overlaps with fishing fleets. Differences
in food availability during the El Nino/La Nina oscillation is another
issue Bell is keen to explore. Birds today are lighter than in 1996 with
average bird weight falling over time. Birds were about 900-1000g in
1996 vs. 690-700g weights being recorded now. Key research gaps are to
understand the reasons for this difference, and why so few young birds
return to the colony to breed.
As we go to print, the Trust is using a
grant from the Great Barrier Local Board to set up a stop-gap trap
network around Hirakimata before chicks leave their burrows in March.
This trapping will help protect the main colony, but won’t stop the
levels of predation found by Bell’s team, there and in other sites
Taiko has moved the Chief Executive of one
of our largest fishing companies. Let’s hope that Sanford’s enthusiasm
is shared and that budgets and resource for DOC on Great Barrier start
to reflect the importance that iwi, our community, MPI, and the Black
Petrel Working Group are now placing on its survival.
• Elizabeth Bell, personal communications 2015 Black Petrel
Population Research 2014/5 season, WMIL (see DOC website for details)
• Report of the Black Petrel Working
Group, September 2015 (Southern Seabird Solutions)
• ByCatch Bylines, Department of
Conservation, Jan 2016.
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Issue 35 Summer 2016