Black Petrel

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The Black Petrel An endemic bird of New Zealand

Contents

3

Ecology Behaviour

7

Population

9

Breeding

13

Threats

19

Conservation

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Bibliography

Ecology Behaviour

Black Petrel’s are listed as vulnerable as there are only around 2,000 breeding pairs remaining in the world.

Introduction The 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.

Family There 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

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Feeding Behaviour 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.

Identification Black 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.

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.

Taxonomy Order

Procellariiformes

Family

Procellariidae

Genus

Procellaria

Species

Procellaria parkinsoni

Common name

Black Petrel

Maori name

Taiko

Other names

Parkinson’s Petrel

Ecology Behaviour Habitat Black 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 Galåpagos Islands, northern Peru and southern Mexico for New Zealand’s winter.

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Australia

New Zealand

Mexico

Galรกpagos Islands

Peru

Little Barrier Island Great Barrier Island Auckland

Breeding site Foraging Range Migration

Population

Proportion

1.0 100

Survival Recapture

0.8 80

0.6 60

1996

1998

2000

2002

2004

Probability of Survival and Recapture of the Black Petrel

Little Barrier Island On 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 Island Black 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

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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.

The overall estimate of the total population of Black Petrel is around 10,000 birds.

Distribution of Black Petrel’s Black 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

Breeding

Black Petrels only lay a single egg each breeding season.

Jan

Nov

Mar

Sept

May

Jul

Annual Breeding Cycle

At colonies Egg laying Incubating Chick rearing

Breeding Habitat Black 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 Cycle Black 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

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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 Rate The 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.

Breeding Success of Chicks Breeding success from 2006 breeding season, showing the percentages of outcomes of the 186 chicks that hatched from 257 eggs.

Breeding Success of Eggs Breeding success of breeding season (2006), representing the percentages of outcomes of the 257 eggs laid that year.

Fledged Predated Unknown

Hatched Crushed Predated Disappeared Dead Embryo

1.0

Bred successfully Didn’t breed Failed breeding

0.8

Proportion

0.6

0.4

0.2

0.0 1996

2000

The proportion of breeding outcomes

2004

2008

The vulnerability and elusive lifestyles of the Black Petrel has made them notoriously difficult to study.

Threats

Reduced Breeding Habitat of the Black Petrel No Black Petrels Breeding area before introduced predators Current breeding area

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Some years all the fledglings on Little Barrier Island have been killed by cats.

Chicks Eggs

Number of eggs or chicks

12

9

6

3

0 1997

1998

1999

2000

Number of Predated Eggs and Chicks The average number of eggs laid per year is 166 with an average of 133 hatched chicks

Rat and Feral Cat Predation

People

Introduced 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.

A 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 Change El 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 1,000 m of the highest mountain top within its range (621 m).

2001

2002

2003

2004

Threats

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Seagull Shag Petrel Gannet Albatross Other

Percentage of total birds caught

35

25

15

5

Type of seabirds caught

Recreational Fishing In 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

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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.

44.9% of total bird caught were Petrels, some of

which will be Black Petrels.

19.5% of New Zealanders engage in fishing as a

recreational hobby every year.

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.

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Seagull Shag Petrel Gannet Albatross

Percentage of incidents

60

40

20

Tangled

Capture Method Capture method that caught birds as a percentage of the total number of incidents.

Internally Hooked

Externally Hooked

Threats

Locations of Black Petrel Captures Between 1997 and 2009, 49 Black Petrel captures were recorded commercial fisheries.

Capture location

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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 0 0.1

1

2.5

5

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.

Commercial Fishing Seabirds 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.

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Conservation

Black Petrel clearly stood out as the species the most at risk from commercial fishing activities in New Zealand.

Protection Black 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 Measures The 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

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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 Measures There 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

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.

Palmers Track

Kauri Dam Track

Shortcut track

Mt Hobson

N Southern Fork Track

Black Petrel Study Burrows Location of the Black Petrel study burrows and census grids within the study site on Great Barrier Island, that are annually monitored by DoC.

Bibliography American Birding. (2006). Black Petrels (2006). Retrieved 2 March 2011, from

Ministry of Fisheries. (2010). New Zealand Fisheries at a Glance, Seabirds:

www.aba.org/birding/v38n6p64w1.pdf

The Problem. Retrieved March 5, 2011 from: www.fish.govt.nz/en-nz/ Fisheries+at+a+glance/default.htm

Arkive (n.d.). Black Petrel (Procellaria parkinsoni). Retrieved March 17, 2011 from: www.arkive.org/parkinsons-petrel/procellaria-parkinsoni/

New Zealand Birds. (n.d.) Black petrel. Retrieved March 7, 2011 from: www.nzbirds. com/birds/blackpetrel.html

Bird Life International. (n.d.) Parkinson’s Petrel Procellaria parkinsoni. Retrieved March 5, 2011 from: www.birdlife.org/datazone/speciesfactsheet.php?id=3923

Ocean Wanderers. (n.d.). (Parkinson’s) Black Petrel (Procellaria parkinsoni).

Retrieved March 18, 2011 from: www.oceanwanderers.com/ParkBlkPet.html

Chambers, S. (2007). New Zealand Birds: An identification guide. Auckland: Reed Books

Ombler, K. (2007). Where to Wathc Birds in New Zealand. Auckland: New Holland Publishers

Cometti, R. (1986). Little Barrier Island: New Zealand’s foremost wildlife sanctuary., Hong Kong: Hodder & Stoughton Ltd.

PLos One. (n.d.) Black Petrels (Procellaria parkinsoni) Patrol the Ocean Shelf-Break: GPS Tracking of a Vulnerable Procellariiform Seabird. Retrieved March 7, 2011 from

Department of Conservation. (2001). Preliminary modelling of Black Petrel

www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009236

(Procellaria parkinsoni) to access population status. Retrieved March 5, 2011 from: www.doc.govt.nz/upload/documents/science-and-technical/dsis2.pdf

Victoria University of Wellington. (n.d.). A History of Birds in New Zealand; Procellaria parkinsoni (Black Petrel). Retrieved March 6, 2011 from: www.nzetc.org/tm/

International Union for Conservation of Nature and Natural Resources. (n.d.). The IUCN Red List of Threatened Species. Retrieved March 17, 2011 from: Procellaria parkinsoni www.iucnredlist.org/apps/redlist/details/144872/0 Ministry of Fisheries. (2010). Fisheries Risk to the Population viability of Black Petrel.

Retrieved March 13, 2011 from: http://kea.massey.ac.nz/search~S4?/Xblack+petrel &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

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