black petrel
DESCRIPTION
The Black Petrel is a threatened endemic bird of New Zealand, this is an informative booklet outlining the threats that are reducing the number of Black Petrels.TRANSCRIPT
1
The
Blac
k Pe
trel
An
ende
mic
bird
of N
ew Z
eala
nd
Cont
ents
3 Ecology Behaviour
7 Population
9 Breeding
13 Threats
19 Conservation
21 Bibliography
IntroductionThe Black Petrel is a medium sized
petrel, which is an endemic seabird of
New Zealand. They are listed as vulnerable
(VU D2 on the IUCN Red List) with only
around 2000 breeding pairs remaining
which are restricted to the islands of Great
Barrier and Little Barrier, New Zealand. Their
restricted habitat, predation from feral cats
and rodents combined with the uncertain
impacts from long-line fishing have all
contributed to the Black Petrel’s vulnerability.
Efforts are being made to better monitor
the population of the birds and continuing
research contributes to the understanding
of the birds which is key to preserving the
population of Black Petrel’s.
FamilyThere are 66 species in the petrel family,
and all spend most of their lives at sea where
they feed on a variety of planktonic animals,
squid and fish.
The genus Procellaria consists of five
species of medium to large petrels of which
Feeding Behaviour Black Petrel birds are a colonial
burrow-nesting, annually -breeding species
that can live to the age of thirty. Black
Petrel’s predominantly live an oceanic
lifestyle, which makes their behaviour
difficult to study.
Black Petrel’s feeding behaviour involves
surface feeding and diving in groups. It has
been recorded that they can dive down
further than 10 m in search of food. Its diet
is dominated by squid and supplemented by
tunicates, crustaceans and cyclostomes.
the Black Petrel, Procellaria parkinsoni, is
the smallest. The order which the Black
Petrel belongs to; Procellariiformes, are
referred to as ‘tubenoses’ because of their
unique bills which allows them to excrete salt
water through their nostril leaving the water
for them to drink.
IdentificationBlack Petrel’s are medium sized petrel’s,
46 cm in size, weighing roughly 700 grams,
with a wingspan of 1 m.
The male and female Black Petrel’s entire
plumage is sooty black in colour, with the
feathers of their back and mantle narrowly
edged with a lighter shade. Their iris’ are
also black along with their feet and legs.
The contrasting feature of the bird is its bill,
which is yellowish-grey, shaded with black
tip on adults or a blue-grey on juveniles.
Their legs and feet are also black in colour.
The young is first thickly covered with sooty
down, which eventually turns into the adult
plumage of black feathers.
Ecol
ogy
Beha
viou
r Black Petrel’s are listed as vulnerable as
there are only around 2,000 breeding pairs
remaining in the world.
3
TaxonomyOrder Procellariiformes
Family Procellariidae
Genus Procellaria
Species Procellaria
parkinsoni
Common name Black Petrel
Maori name Taiko
Other names Parkinson’s Petrel
:
5
HabitatBlack Petrel are seabirds which can spend
years on end out at sea surviving even the
most resilient storms, returning to land only
for breeding.
Black Petrel once bred widely in the
mountains over the North Island and the
North West of Nelson in New Zealand. By
the 1960s the Black Petrel had disappeared
from the mainland because with the growing
population of New Zealand came the
replacement of forests with farmland and
introduction of rats, cats, stoats and other
predators. Little and Great Barrier Islands in
the Hauraki Gulf to the east of Auckland are
the birds only remaining breeding habitats.
The foraging range of Black Petrel is
around New Zealand and extends out to
Western Australia. Research shows the birds preferentially forage on the continental shelf
or at seamounts. The Black Petrel migrates
east to the eastern Pacific Ocean between
the Galápagos Islands, northern Peru and
southern Mexico for New Zealand’s winter.
Ecol
ogy
Beha
viou
r
New Zealand
Australia
Breeding site
Foraging Range
Migration
Great Barrier Island
Little Barrier Island
Auckland
Galápagos Islands
Mexico
Peru
60
80
100
7
Little Barrier IslandOn Little Barrier, it was abundant in the late
1800s but the population was decimated,
mainly by feral cats, until predators were
eradicated in 1980. The Little Barrier Island
colony was originally monitored between
1971 and 1983 and the total breeding
population was estimated to be between 50
and 100 pairs. After the feral cat eradication,
in order to supplement the colony, 249
chicks from Great Barrier Island were
transferred to Little Barrier Island between
1986 and 1990 and the Little Barrier colony
was then monitored annually until 2000.
The Little Barrier Island population is
now thought to be gradually increasing, but
further research is needed to create more
accurate estimates of the population on
Little Barrier Island.
Great Barrier IslandBlack Petrels were first officially recorded on
Great Barrier Island in 1960, but had been
observed by earlier naturalists and harvested
by the local Maoris before this time. At this
time no census or population estimate was
given. From surveys in the late 1970s the
population was thought to be 500 –1,000
breeding pairs, but recent surveys suggest
the population is more than 1,300 breeding
pairs and between 3,551 – 5,021 individuals.
However, a subsample of 100 burrows
monitored for 10 years or more indicated a
slight decrease in population size between
1996 and 2006. The mean probability of
recapture from one year to the next was
78.36%. Additional extensive surveys are
needed to gain a better estimate of the whole
island population and to determine trends for
the total population with more confidence.
Analyses of both juvenile and adult survival
are ongoing. The mean survival of adult
birds estimated to date is 77.9%, which is
considerably lower than other petrels of
similar size. This contrasts with an estimate
of juvenile Black Petrels survival (over three
years of age) of 92.3%, which is very high.
Analysis of 421 birds of known sex suggested
that there was no significant difference
between male and female adult survival.
The low adult survival could be due to low
detectability of birds that move out of the
study area, but this hypothesis needs to be
further investigated.
Total Population Black Petrel breed on Great and Little Barrier
Islands, New Zealand, where the total
population is 1,300 and 100 breeding pairs
respectively, equating to a total population of
an estimated 5,000 individuals. The estimate
of 1,300 pairs on Great Barrier Island is lower
than previously thought but probably reflects
improved information rather than a decline,
however it is not a complete survey and
although it covers the majority of the island’s
population further research is needed to
assess the true population size.
The overall estimate of the total population
of Black Petrel, including the Black Petrel’s
out at sea, is around 10,000 individual birds.
Probability of Survival and Recapture of the Black Petrel
1996 1998 2000 2002 2004
Pro
port
ion
Survival
Recapture
Popu
latio
n
1.0
0.8
0.6
Distribution of Black Petrel’sBlack Petrel’s are estimated to have a population of 10,000 with
only 28% of them being recorded inhabiting Little and Great
Barrier Island, while the rest of them remain out to sea.
200 Black Petrel
Birds out to sea
Birds on land
The overall estimate of the total population
of Black Petrel is around 10,000 birds.
Bree
ding
9
Breeding HabitatBlack Petrel’s breed in only two colonies:
approximately 1,300 annual pairs on Great
Barrier Island, and approximately 100 annual
pairs on Little Barrier Island. The summit of
Mount Hobson is the main breeding area on
Great Barrier Island for them.
Breeding CycleBlack Petrels nest in burrows, usually above
400 m in altitude, and within 50 m either
side of ridge lines. They are an annually
breeding species, with each breeding cycle
lasting about nine months. The breeding
season starts in October, when males
prepare burrows and try to attract a mate.
Most eggs are laid in December, and the
peak period for hatching is early February
(the typical incubation period is 57 days).
Chick rearing takes about 107 days, with the
chicks fledging in May/June at about three
months old. During the breeding season
adults forage mostly to the west and east of
northern New Zealand. Both adult and
newly fledged birds spend the winter off the
west coast of North and South America.
The youngest bird recorded returning to the
Great Barrier Island colony was three years
of age and first breeding has been recorded
at five years at this site. The youngest bird
recorded returning to the Little Barrier Island
colony was five years of age with first
breeding recorded there at six years.
Success RateThe mean age of first breeding for Black
Petrel is estimated to be 6.7 years. Before
this, new adults spend an average of
1.2 years in the colony as pre-breeders, with
only 3% skipping the pre-breeder phase.
Of birds that appear in the study area as
pre-breeders and survive to breed, only 68%
do so in the study area. Once birds start
breeding, their annual survival rate is 0.89,
80% breed each year, and of those, 77%
are successful (i.e., produce a fledgling).
Survival rates before the pre-breeder stage
are not well determined because we can’t
distinguish mortality from emigration (birds
that breed in an area away from where they
were hatched).
A number of Great Barrier Island study
burrows has been monitored intensively
since the 1995 / 96 breeding season allowing
for breeding success, juvenile and adult
survival to be determined for this period.
Breeding success varies from 69% to 84%
(chicks fledged from eggs laid), with an
average of 76% of burrows fledging a chick.
Jan
Mar
May
Jul
Sept
Nov
Annual Breeding Cycle
At colonies
Egg laying
Incubating
Chick rearing
Black Petrels only lay a single egg each
breeding season.
Fledged
Predated
Unknown
Breeding Success of EggsBreeding success of breeding season (2006),
representing the percentages of outcomes of the
257 eggs laid that year.
Breeding Success of ChicksBreeding success from 2006 breeding season,
showing the percentages of outcomes of the 186
chicks that hatched from 257 eggs.
1.0
0.8
0.6
0.4
0.2
0.01996 2000 2004 2008
Pro
port
ion
The proportion of breeding outcomes
Hatched
Crushed
Predated
Disappeared
Dead Embryo
Bred successfully
Didn’t breed
Failed breeding
The vulnerability and elusive lifestyles of the Black Petrel has made them notoriously difficult to study.
13
No Black Petrels
Breeding area before introduced predators
Current breeding area
Reduced Breeding Habitat of the Black Petrel
Thre
ats
Rat and Feral Cat PredationIntroduced cats decimated the Little Barrier
Island population, killing up to 100% of
fledglings in some years, and taking adults.
Introduced cats cause minor interference on
Great Barrier Island, but breeding success
is high (80% in 2004 /5). Rats are present
on Great Barrier Island but have little effect
on this species. Rats were eradicated from
Little Barrier Island in 2004. Rats, stray dogs,
feral pigs, along with the cats, may also be a
threat on Great Barrier Island.
There were three incidents of cat predation
(1.5%) on chicks, while rats predated 0.5%
of the eggs laid within the study burrows in
the 2006 season. Predation by cats occurred
in three different areas – Palmers Track,
Kauri Dam, and the Summit. Juvenile petrels
are vulnerable to feral cat predation as soon
as they leave the burrows to strengthen
wings and practise flying. Ten chicks have
been predated by cats over the past five
seasons. It is important to continue control
the cat population with trapping in the area.
Eggs are more likely to be predated by rats.
PeopleA recent estimate indicates that about 6640
people visit Mount Hobson on Great Barrier
Island, each year, which has little or no direct
impact on the breeding success of the Black
Petrel. The construction of raised walkways
around the summit has decreased damage
to the environment, and burrows. However,
serious erosion continues to occur along the
summit ends of the South Fork and Palmers
Tracks. Extended walkway construction in
these areas is recommended. This should be
done with full consultation with the authors
to prevent the accidental destruction of
burrows, since certain places along these
tracks have high burrow densities.
Climate ChangeEl Niño fluctuations may also affect the
population in this zone. The species is
potentially threatened by climate change
because it has a geographically bounded
distribution: its altitudinal distribution
falls entirely within 1,000m of the highest
mountain top within its range (621m).
15
12
9
6
3
0
Number of Predated Eggs and ChicksThe average number of eggs laid per year is
166 with an average of 133 hatched chicks
1997 1998 1999 2000 2001 2002 2003 2004
Num
ber
of e
ggs
or c
hick
s
Some years all the fledglings on Little
Barrier Island have been killed by cats.Chicks
Eggs
Thre
ats
15
Recreational FishingIn New Zealand, participation in recreational
fishing is high. A recent survey estimated
that 19.5% of the adult population go
saltwater fishing during a year, with 2.5% of
the adult population (81,000 people) fishing
at least once during a week, catching 25,000
tonnes annually. It is estimated 4.81 (4.41
to 5.23) million hours of fishing from trailer
boats in northeastern New Zealand, where
the Black Petrel lives.
A boat ramp survey was carried out
in collaboration with Blue Water Marine
Research during the summer of 2007–08.
During the survey, 763 interviews were
conducted (654 on the northeast coast, and
109 in Otago). This survey has provided the
first quantitative information on the rates
of seabird capture by recreational fishers,
as well as information on the nature of the
interactions. Across all the survey, 47%
of fishers recalled witnessing a bird being
caught at some stage in the past, and there
were 21 birds caught on the day of the
interview. This was equivalent to a capture
rate of 0.22 (95% c.i: 0.13 to 0.34) birds per
100 hours of fishing. Observers on 57 charter
trips also recorded seabird captures, with a
capture rate of 0.36 (95% c.i: 0.09 to 0.66)
birds per 100 fisher hours, similar to the
rate found during the boat ramp surveys.
Although the number of interactions is high,
the birds were reported as unharmed in 77%
of the capture incidents that were recalled.
This results in 11,500 (6,600 to 17,200) birds
hooked or tangled each year, some of which
will be Black Petrels.
Non-commercial fisheries involve many
individual participants and are geographically
spread out. The lack of centralisation makes
data collection difficult, and to date there
has been no systematic study of the impacts
of recreational fishing on seabirds. The
intensity of recreational fishing creates a
small rate of interactions between individual
fishers and birds, which may have an
impact on the population level. The near
shore region is where recreational fisheries
are concentrated. Until recently, Ministry of
Fisheries observers have typically not been
placed on the smaller vessels that target
inshore species, and the impacts of fishing
on Black Petrels that are largely unknown.
Type of seabirds caught
45
35
25
15
5
Per
cent
age
of to
tal b
irds
caug
ht
Seagull
Shag
Petrel
Gannet
Albatross
Other
19.5% of New Zealanders engage in fishing as a
recreational hobby every year.
44.9% of total bird caught were Petrels, some of
which will be Black Petrels.
60% of fishing trips over 5 km from shore
attracted petrels, 30% within 5 km and only 10%
within an Estuary area in the North Island.
Per
cent
age
of in
cide
nts
Capture MethodCapture method that caught birds as a percentage
of the total number of incidents.
Tangled Internally Hooked Externally Hooked
80
60
40
20
Seagull
Shag
Petrel
Gannet
Albatross
Type of seabirds caught
Thre
ats
17
Capture location
Locations of Black Petrel Captures
Between 1997 and 2009, 49 Black Petrel captures
were recorded commercial fisheries.
Commercial FishingSeabirds are caught in a range of fisheries,
and the management of fisheries to ensure
the long-term viability of seabirds requires
an understanding of the risks to their
sustainability. In order to evaluate whether
the viability of seabirds is jeopardised by
fisheries by-catch, the number of annual
kills needs to be compared with the capacity
of the populations to replace those losses.
Recent research by Dragonfly studied 64
species, of seabirds where the Black Petrel
clearly stood out as the species the most at
risk from commercial fishing activities within
the New Zealand Exclusive Economic Zone.
With an average number of annual potential
kills estimated to be nearly 10 times higher
than the Potential Biological Removal index,
the study suggests that the Black Petrel
species should become the primary subject
of more detailed research and management.
Fishing is a big industry in New Zealand
with 1,278 commercial fishing vessels
registered which export $1.42 billion worth of
seafood every year.
Black Petrel’s often scavenge the fishing
boat waste, and are caught by commercial
longliners in New Zealand waters.
Most observed captures were close to
Black Petrel’s breeding grounds, primarily in
the bottom longline snapper fishery, but also
in the bottom longline bluenose fishery, and
in inshore trawl fisheries. From 29 observed
captures, we estimated that between 663
and 1289 birds may have potentially been
killed each year in the period 2003 to 2009.
These kills exceeded the Potential Biological
Removal index, which was estimated to be
between 64 and 157 mortalities per year.
There was no significant difference in the
vulnerability to capture, the number of
potential kills, or in the risk ratio of Black
Petrel between the periods of 2003–04 to
2005–06 and 2006–07 to 2008–09.
Black Petrel are also vulnerable to capture
by fisheries, especially longline fishing,
during migration to the east Pacific off
Ecuador and Peru where it is a near-obligate
associate of small crustaceans.
Black Petrel
NZ King Shag
Salvin’s Albatross
Yellow-Eyed Penguin
Gibson’s Albatross
Spotted Shag
Pitt Island Shag
Soft Plumaged Petrel
Bounty Island Shag
Sooty Shearwater
Kerm Petrel
Campbell Island Shag
Antarctic Prion
Masked Booby
Common White Tern
Risk Ratio (kills / PBR)Risk ratio (total annual potential kills / PBR) for a sample of the studied birds.
The threshold where the number of potential bird kills equals the PBR is
represented by the vertical black line.
0 0.1 1 2.5 5 10
19
ProtectionBlack Petrels are specifically covered by the
International Agreement on the Conservation
of Albatrosses and Petrels (2001) which
obliges signatories to reduce incidental
mortality, control detrimental non-native
species, protect critical habitats and support
research into the highlighted species.
Current MeasuresThe Department of Conservation and Wildlife
Management International Limited have
been taking steps to preserve the population
of Black Petrel’s for many years. Cats were
eradicated on Little Barrier Island by 1980.
Between 1986 and 1990, 249 fledglings
were transferred from Great Barrier to
Little Barrier Island in an attempt to boost
population size. Follow-up monitoring
indicates mixed results. The colony on Little
Barrier is monitored every breeding season
to assess breeding success. An ongoing
long-term population study of Black Petrel
was initiated on Great Barrier in 1996. This
study will assist in identifying the effects
very important for determining national
and international fisheries risk for the
Black Petrel. Increasing awareness of both
recreational and commercial fisheries of
the threat they pose to the Black Petrel
and their vulnerability to being captured is
also a priority. Also explaining solutions to
fishermen that reduce the problem like using
weighted line and being careful with disposal
of offal is needed. Further developing
mitigation devices and techniques that
minimise fisheries by-catch, is also a priority.
If monitoring indicates that any predators
are causing a decline in population on Great
Barrier Island then appropriate management
strategies will take place to resolve this. The
eradication of rats from Little Barrier Island is
another current target.
that long-line fishing, rat and cat predation,
and habitat disturbance may have on
the population. The population estimate
has been updated, ensuring that any
population changes will be detected in time
to implement the appropriate management
strategies. The main objective of the study is
to undertake an annual census of the Black
Petrel population on Great Barrier Island
via burrow monitoring and the banding of
adults and fledglings to determine adult
mortality, breeding success and recruitment.
More accurate research will ensure the
preservation of the Black Petrel species.
Proposed MeasuresThere are plans to complete an accurate
census of both islands and continue to
monitor Great Barrier Island populations
annually to determine trends, and assess
breeding success. From this research
follow-up reports of mainland breeding sites
will be generated to analyse data. Accurate
foraging and distribution information is also
Cons
erva
tion Black Petrel clearly stood out as the
species the most at risk from commercial
fishing activities in New Zealand.
Black Petrel Study BurrowsLocation of the Black Petrel study burrows and census grids within the study
site on Great Barrier Island, that are annually monitored by DoC.
Shortcut track
Kauri Dam Track
Southern Fork Track
Mt Hobson
Palmers Track
N
21
American Birding. (2006). Black Petrels (2006). Retrieved 2 March 2011, from
www.aba.org/birding/v38n6p64w1.pdf
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www.arkive.org/parkinsons-petrel/procellaria-parkinsoni/
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March 5, 2011 from: www.birdlife.org/datazone/speciesfactsheet.php?id=3923
Chambers, S. (2007). New Zealand Birds: An identification guide. Auckland:
Reed Books
Cometti, R. (1986). Little Barrier Island: New Zealand’s foremost wildlife sanctuary.,
Hong Kong: Hodder & Stoughton Ltd.
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www.doc.govt.nz/upload/documents/science-and-technical/dsis2.pdf
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parkinsoni www.iucnredlist.org/apps/redlist/details/144872/0
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&searchscope=4&SORT=DZ/Xblack+petrel&searchscope=4&SORT=DZ&SUBKEY=
black%20petrel/1%2C5%2C5%2CB/c856740911&FF=Xblack+petrel&1%2C1%2C
%2C1%2C0
Bibl
iogr
aphy
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The Problem. Retrieved March 5, 2011 from: www.fish.govt.nz/en-nz/
Fisheries+at+a+glance/default.htm
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www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009236
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