Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Vulnerable as Leucocarbo atriceps purpurascens
Listed marine as Phalacrocorax purpurascens
Recovery Plan Decision Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
 
Adopted/Made Recovery Plans National Recovery Plan for Ten Species of Seabirds 2005-2010 (Department of the Environment and Heritage (DEH), 2005f) [Recovery Plan] as Leucocarbo atriceps purpurascens.
 
Other EPBC Act Plans Threat Abatement Plan for predation by feral cats (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2008zzp) [Threat Abatement Plan].
 
Policy Statements and Guidelines Issues Paper: Population status and threats to ten seabird species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 (Department of the Environment and Heritage (DEH), 2005p) [Admin Guideline].
 
Survey Guidelines for Australia's Threatened Birds. EPBC Act survey guidelines 6.2 (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2010l) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Phalacrocorax purpurascens.
 
Declaration under section 248 of the Environment Protection and Biodiversity Conservation Act 1999 - List of Marine Species (Commonwealth of Australia, 2000c) [Legislative Instrument] as Phalacrocorax purpurascens.
 
Amendment to the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (11/04/2007) (Commonwealth of Australia, 2007f) [Legislative Instrument] as Phalacrocorax albiventer purpurascens.
 
Amendment to the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (72) (15/12/2008) (Commonwealth of Australia, 2008k) [Legislative Instrument] as Leucocarbo atriceps purpurascens.
 
State Government
    Documents and Websites
TAS:Leucocarbo atriceps purpurascens (Imperial Shag (Macquarie Island)): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2014vm) [State Action Plan].
State Listing Status
TAS: Listed as Vulnerable (Threatened Species Protection Act 1995 (Tasmania): September 2012 list) as Leucocarbo atriceps purpurascens
Non-statutory Listing Status
NGO: Listed as Vulnerable (The Action Plan for Australian Birds 2010)
Scientific name Leucocarbo atriceps purpurascens [66995]
Family Phalacrocoracidae:Pelecaniformes:Aves:Chordata:Animalia
Species author  
Infraspecies author (Brandt, 1837)
Reference  
Other names Leucocarbo purpurescens [81227]
Phalacrocorax albiventer purpurascens [82033]
Phalacrocorax purpurascens [64685]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Phalacrocorax albiventer purpurascens

Common name: Macquarie Shag

Other names: Imperial Shag (Macquarie Island), Imperial Shag (if considered conspecific with Leucocarbo atriceps), Blue-eyed Cormorant, Imperial Cormorant, Blue-eyed Shag and King Shag.
Cormorants and shags are distinctive aquatic birds typically breeding on both mainland and island sites. Those that are restricted to remote islands are typically sedentary. Recent reviews of the taxonomy have resulted in the recognition at the specific level of several forms restricted to particular islands (Shirihai 2002). The Macquarie Shag represents such forms and has been the subject of several studies (Brothers 1985, Green 1997a, b; Green & Williams 1997).

The taxonomy of the Imperial Shag complex remains disputed (Green et al. 1990; Green 1997a). Some authors recognised eight subspecies of Leucocarbo atriceps (Christidis & Boles 1994; Harrison 1983; Sibley & Monroe 1990) whilst others (Marchant & Higgins 1990) recognise eight distinct species, with P. albiventer purpurascens restricted to Macquarie Island. Others considered the Imperial Shag (L. atriceps) group to comprise multiple subspecies, including P. albiventer purpurascens (Turbott 1990; BirdLife International 2004e). Such a treatment consequently results in the Least Concern rating by BirdLife International (2004e).

The Macquarie Shag is a medium-sized, black and white marine shag. The adult form reaches a length of 75 cm with a wingspan of 110 cm and weighs between 2.5 and 3.5 kg. Sexes are alike and both undergo seasonal plumage changes when not breeding, including; the absence of crest and plumes, dull/faded dorsal plumage and soft parts, and yellow caruncles (Marchant & Higgins 1990).

Adult breeding birds have a glossy black top and sides of head and hindneck with a black crest on the forehead. Demarkation between the black cap and white face starts at the gape and extends back below ear-coverts leaving the lower cheeks and throat white, and giving the face a dark appearance. Upper wing-coverts are a blackish-brown with an oily green sheen. The tail is black with white bases to the shafts, while the throat, sides of the neck and the rest of the underparts are white. The bill is grey with a horn colored patch near the tip of the lower mandible and a prominent pair of orange caruncles above the base of the bill. The eye ring is blue and the iris is dark brown. The rest of the facial skin is orange-brown with yellow spots and legs and feet are pink to purple-grey (Marchant & Higgins 1990).

Juveniles are distinguished from adults as they are predominately brown with a slight green sheen above and white below. The extent of the pale-brown alar patches varies. Juveniles do not have crest, plumes or caruncles. Facial skin is bluish grey and legs and feet are a pink-brown (Marchant & Higgins 1990).

The Macquarie Shag is restricted to Macquarie Island and the adjacent Bishop Island and Clerk Island, 33 km to the south (Marchant & Higgins 1990). There are 23 recorded breeding sites for Macquarie Shags, with all but two sites restricted to offshore stacks or islets, or stacks attached to the shore (Brothers 1985). Not all sites are used each year, and birds may interchange between colonies. Macquarie Shags have been recorded nesting at the adjacent Bishop and Clerk Islets (Lugg et al. 1978).

The Macquarie Shag is sedentary, making only local movements around the islands. Brothers (1985) reported that they are poor fliers, unable to make headway in strong winds (> 40 knots), and their morphology (small wings, heavy bones and water permeable plumage) restricted long range movements. Macquarie Shags are restricted to inshore waters during the breeding season, but may travel further offshore, up to 100 km, during the winter season (Brothers 1985).

The extent of occurrence is estimated at 75 km² with high reliability (Garnett & Crowley 2000).

The area of occupancy is estimated at 50 km² with high reliability (Garnett & Crowley 2000).

The number of Macquarie Shags breeding on the island in the 1970s was estimated by Brothers (1985) at 660 breeding pairs, an estimate that does not include the nests recorded from Bishop and Clerk Islets, where Lugg and colleagues (1978) estimated 100 pairs.

Garnett and Crowley (2000) estimate the total population of the Macquarie Shag to be 760 pairs with 2500 breeding birds. The population estimate of 760 pairs includes around 100 pairs on Bishop and Clerk Islands (although, more recently, 164 nests in three colonies were observed by Brothers (1985)). Between 1975 and 1979, 23 breeding colonies were recorded, 19 of which were active, ranging in size from three to 320 pairs (Garnett & Crowley 2000). However, a 2003 survey on Macquarie Island comprised an island wide search of all known and potential breeding sites. Eleven colonies comprising 472 nesting pairs were located in October 2003. Although it is difficult to detect trends from these data, this figure represents 30% fewer than the 660 pairs observed in 19 sites in the 1970s (Schulz & Lynn 2003).

The number of Macquarie Shags at colonies fluctuates, but this is probably because individual birds move from one colony to another (Garnett & Crowley 2000).

An absence of comparable longitudinal data precludes assessment of population trends for the Macquarie Shag. Further systematic surveys are required to confidently assess trends.

A Macquarie Shag which was banded as a nestling in February 1963 was recovered ten years and nine months later (ABBBS 1974). Brothers (1985) reported that banding records showed that Macquarie Shags can live for at least 13 years.

The Macquarie Shag forages in the subantarctic inshore waters of Macquarie Island and its outlying islands. Its feeding grounds are nearshore, because the sea-bottom drops away steeply. The species feeds mainly along the western shore, which is less steep.

The Macquarie Shag breeds in small (three nests) to large (300 nests) colonies on bare rocky shores and stacks, on stacks attached to the shore, and among boulders on the shoreline (Brothers 1985). Most of the Shag's breeding colonies are exposed to the prevailing westerly winds. The largest breeding colonies are among boulders on the shore of Macquarie Island, because small stacks accommodate fewer pairs (Brothers 1985). Nests on bare rocks are washed clean by water from year to year, because they are not far above the high-tide mark, and are in the spray zone. Macquarie Shags place new nests on the exact site that they used previously (Marchant & Higgins 1990).

The Macquarie Shag roosts solitarily or in small to large (600-800 birds) flocks on bare ground. During the breeding season, most adults, while not incubating, roost together at the seaward edge of the colony. Some birds sleep or preen beside the nest when they are not incubating (Brothers 1985). Large foraging flocks leave roosting and nesting areas before 10am and return about 4pm (W.J.M. Vestjens, as cited in Marchant & Higgins 1990).

The Macquarie Shag is a sedentary species that breed in colonies and are gregarious at roost sites and when feeding. Nest building starts in July. Nests typically comprise a truncated column structure composed of mud, guano and vegetation (Brothers 1985). By mid September, 50% of nests are well formed and by the end of September, birds commence sitting on empty nests (Marchant & Higgins 1990). The Macquarie Shag nests in small groups and colonies. It defends its nest site only, and nests are 1 to 2 m apart (Marchant & Higgins 1990). Clutches are generally comprised of one to three blue-green eggs (Brothers 1985). The earliest egg laying is around the 30th of September, and the latest is in mid-January, but most eggs are laid during the last half of October and the first half of November. Most eggs have hatched by late December. Chicks fledge from late January to mid-February (Brothers 1985; Marchant & Higgins 1990).

Breeding success is problematic to assess given the habit of the young birds moving from their nests before becoming fully independent of parents. During three seasons on Macquarie Island, Brothers (1985) estimated mean success rates of 57 to 61%, reflecting a production rate of 1.0 to 1.9 chicks per nest. Marchant and Higgins (1990) assessed 159 eggs laid during three seasons. Of the 119 (75%) that hatched, 97 of the resulting chicks (82%) survived to January 10th, and 86 (72%) survived to January 29th, giving a possible total success of 57% to 61%. The mean fledging rate in these three seasons was from one to two chicks per nest.

During the breeding season, adult Macquarie Shags forage for only two to four hours at a time, feeding their chicks around six times per day (Brothers 1985).

There are no data on adult or juvenile survival rates for the Macquarie Shag, the mobility of birds among colonies making such assessments difficult.

The Macquarie Shag breeds on Macquarie Island, Bishop and Clerk Islets (Marchant & Higgins 1990).

The Macquarie Shag eats largely fish, some crustaceans and other benthic (bottom-dwelling) invertebrates (Marchant & Higgins 1990). Brothers (1985) found that the bird's diet was comprised entirely of benthic fish, mainly Magellanic Rockcod Paranotothenia magellanica, some Antarctic Plunderfish Harpagifer bispinis and the remainder of fish eaten were probably species of Nototheniidae (cod icefish). One stomach contained crustaceans and fish (Marchant & Higgins 1990).

The Macquarie Shag forages in shallow water, under rocks and in kelp beds (Marchant & Higgins 1990). It hunts entirely by pursuit diving, possibly as deep as 50 m (Brothers 1985). During the breeding season, the species feeds solitarily. From late March to August, flocks of up to 40 birds may feed together, diving simultaneously several times, then flying about 50 m and feeding again (Brothers 1985).

The Macquarie Shag probably does not range more than a few kilometres from Macquarie Island. It is confined to local movements because it cannot make headway against winds that are more than 40 knots (Brothers 1985), and has small wings, heavy bones and water-permeable plumage, preventing long rests on water (Marchant & Higgins 1990). The Macquarie Shag does not fly overland between coasts, so it sometimes becomes stranded on the eastern coast during westerly storms. Populations at Bishop and Clerk Islands probably forage locally (Marchant & Higgins 1990).

Distinctiveness
There are no other species on Macquarie Island that are similar to the Macquarie Shag. Elsewhere, birds that resemble the species include Antarctic Shags P. bransfieldensis, and all blue-eyed cormorants that have sometimes been considered to be one species the Imperial Shag Leucocarbo atriceps, together with the Imperial Shag (Heard Island) Leucocarbo atriceps nivalis (Marchant & Higgins 1990).

Both Heard and Macquarie Shags are considered threatened because the populations are small and restricted in distribution (Marchant & Higgins 1990). As a result, the birds could be adversely affected by effects of climate changes on sea temperature and food supply (Garnett & Crowley 2000) in addition to other threats that affect small and vulnerable species of seabirds, such as, marine pollution and marine debris.

Cats Felis catus were identified as a possible predator of Macquarie Shag chicks, with cats being regularly observed on the periphery of colonies (Selkirk et al. 1990). Cats have since been eradicated from Macquarie Island, but rats Rattus rattus have been observed in disused nest bowls on Macquarie Island (Schulz & Lynn 2003).

The two major causes of mortality of Macquarie Shag nestlings were predation by Subantarctic Skuas, Catharacta lonnbergi (Brothers 1985). Skuas can dislodged large chicks from nests when the chick is only partly covered by a parent.

The effects of adverse weather on breeding success may be manifested not only be physical destruction of nests but also by restricting access to available prey. On Macquarie Island up to 90 % mortality of Shag nestlings has been observed after a single storm (N. Brothers pers comm. in Pemberton & Gales 1987). Storms on Macquarie Island have also been directly implicated in the death of adults when colonies are wave-washed and in severe winter storm events (Schulz & Lynn 2003).

Human mediated deaths have also been recorded with fatal strikes with radio masts quite common (Brothers 1985, Green 1997). The shallow and inshore foraging behaviour of the Shags makes them unlikely candidates for interactions with commercial fishing operations around Macquarie Island. Fishing is prohibited within 3 nautical miles of Macquarie Island, and the only recorded interaction of a Macquarie Shag interacting with fishing vessels relates to an occasion on a trawler targeting toothfish Dissotichus spp. in 2002 when a bird 'landed on the bow of a boat, and flew off leaving a few drops on blood' (AFMA unpublished data, as cited in DEH 2005p).

Starvation is also a common cause of mortality among Macquarie Shag chicks (Brothers 1985).

The following threat abatement recommendations are outlined in the Issues Paper: Population status and threats to ten seabird species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 (DEH 2005p).

  • On Macquarie Island, conduct annual island-wide breeding census, incorporating visits to all sites known to have been used for breeding. Surveys to be timed and recorded so that meaningful assessments of population status and inter-annual variation can be drawn.
  • The presence/status of the Macquarie Island Shag population breeding on Bishop and Clerk Islands should be assessed.
  • Progress feral pest eradication program on Macquarie Island to mitigate possibility of rat predation on eggs and chicks.
  • Ensure effective quarantine programs at all breeding sites to minimise introduction of pests.
  • Where possible long radio and HF dipole aerials should be replaced by whip aerials to reduce the incidental morality caused by bird strike.
  • All colonies to be protected and managed in such a way that human disturbance is minimised.
  • Maintain current prohibitions of fishing in waters immediately adjacent to the breeding islands.

The Action Plan for Australian Birds and the Issues Paper: Population status and threats to ten seabird species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 provide guides to threat abatement and management strategies for the Macquarie Shag (DEH 2005p; Garnett & Crowley 2000).

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Ecosystem/Community Stresses:Ecosystem Degradation:Decline in habitat quality Phalacrocorax albiventer purpurascensin Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006tb) [Internet].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation Felis catus (Cat, House Cat, Domestic Cat) Phalacrocorax albiventer purpurascensin Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006tb) [Internet].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Predation, competition, habitat degradation and/or spread of pathogens by introduced species Phalacrocorax albiventer purpurascensin Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006tb) [Internet].
Transportation and Service Corridors:Utility and Service Lines:Collision with human infrastructure Phalacrocorax albiventer purpurascensin Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006tb) [Internet].

Australian Bird and Bat Banding Scheme (ABBBS) (1974). Recovery round-up. Australian Bird Bander. 12:16-18.

BirdLife International (2004e). Threatened birds of the world 2004. Cambridge, U.K: BirdLife International.

Brothers, N. (1985). Breeding biology, diet and morphometrics of the King Shag, Phalacrocorax albiventer purpurascens at Macquarie Island. Australian Wildlife Research. 12:81--94.

Christidis, L. & W.E. Boles (1994). The Taxonomy and Species of Birds of Australia and its Territories. Royal Australasian Ornithologists Union Monograph 2. Melbourne, Victoria: Royal Australasian Ornithologists Union.

Department of the Environment and Heritage (DEH) (2005p). Issues Paper: Population status and threats to ten seabird species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/pubs/seabirds-issues.pdf. [Accessed: 11-Apr-2008].

Garnett, S.T. & G.M. Crowley (2000). The Action Plan for Australian Birds 2000. [Online]. Canberra, ACT: Environment Australia and Birds Australia. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/action/birds2000/index.html.

Green, K. (1997a). Biology of the Heard Island Shag Phalacrocorax nivalis. 1. Breeding behaviour. Emu. 97:60-66.

Green, K. (1997b). Biology of the Heard Island Shag Phalacrocorax nivalis. 2. Breeding. Emu. 97:67-75.

Green, K. & R. Williams (1997). Biology of the Heard Island Shag Phalacrocorax nivalis. 3. Foraging, diet and diving behaviour. Emu. 97:76--93.

Green, K., R. Williams, E.J. Woehler, H.R. Burton, N.J. Gales & R.T. Jones (1990). Diet of the Heard Island Cormorant Phalacrocorax atriceps nivalis. Antarctic Science. 2:139--141.

Harrison, P (1983). Seabirds: An Identification Guide. London: Croom Helm.

Lugg, D.J., G.W. Johnstone & B.J. and Griffin (1978). The outlying islands of Macquarie Island. Journal of Geography. 144:277-87.

Magrath, M.J.L., M.A. Weston, P. Olsen & M. Antos (2004). Draft Survey Standards for Birds: Species Accounts. Melbourne, Victoria: Report for the Department of the Environment and Heritage by Birds Australia.

Marchant, S. & P.J. Higgins, eds. (1990). Handbook of Australian, New Zealand and Antarctic Birds. Volume One - Ratites to Ducks. Melbourne, Victoria: Oxford University Press.

Pemberton, D. & R. Gales (1987). Notes on the status and breeding of the Imperial , Phalacrocorax atriceps at Heard Island. Cormorant. 15:33-40.

Schulz, M. & Lynn, J (2003). Burrowing petrels on Macquarie Island, late March to early December 2003. Report to Nature Conservation Branch, Department of Primary Industries, Water and Environment, Hobart, Tasmania. Department of Primary Industries, Water and Environment, Hobart, Tasmania.

Selkirk, P.M., R.D. Seppelt & and D.R. Selkirk (1990). Subantarctic Macquarie Island: environment and biology. Cambridge University Press, Cambridge.

Shirihai, H. (2002). The Complete Guide to Antarctic Wildlife. Princeton & Oxford: Princeton University Press.

Sibley, C.G. & B.L. Monroe (1990). Distribution and Taxonomy of the Birds of the World. New Haven, Connecticut: Yale University Press.

Turbott, E.G. (1990). Checklist of the birds of New Zealand and the Ross Dependency, Antarctica. Random Century, Auckland.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Leucocarbo atriceps purpurascens in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 2 Oct 2014 19:25:54 +1000.