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Phalacrocorax neglectus 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Suliformes Phalacrocoracidae

Scientific Name: Phalacrocorax neglectus
Species Authority: (Wahlberg, 1855)
Common Name(s):
English Bank Cormorant
French Cormoran des bancs
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification information: 76 cm.  Large, matt black-and-brown cormorant lacking bright gular patch.  Adult in nuptials shows varying amounts of white philo-plumes on head and rump.  These quickly vanish after courtship and egg-laying. Bronzed-greenish upperparts with dark edging to mantle and wing-coverts.  Slight erectile crest appears as small bump on forehead.  Juvenile and immature lack bronzing.  Similar spp.  Differs from Cape Cormorant P. capensis by lack of orange gular patch, stouter bill, thicker and less snake-like neck, and broader, deeper head, also brown rather than blue iris.  Voice  Loud wheeee, accompanied by loud foot-slapping on rocks, as male lands in colony.

Assessment Information [top]

Red List Category & Criteria: Endangered A2ace+3ce+4ace ver 3.1
Year Published: 2017
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Kemper, J., Ludynia, K., Morris, T., Sherley, R. & Simmons, R.
Facilitator/Compiler(s): Anderson, O., Ashpole, J, Ekstrom, J., Moreno, R., Pilgrim, J., Robertson, P., Symes, A., Taylor, J., Martin, R
Justification:

This species is listed as Endangered since a very rapid decline in its small population has been observed on the breeding grounds as a result of human disturbance, displacement by seals, food shortages and low quality food. 

Previously published Red List assessments:

Geographic Range [top]

Range Description:

Phalacrocorax neglectus is known to breed at 45 localities between Hollambird Island, Namibia, and Quoin Rock, South Africa.  Birds in breeding plumage have been sighted as far north as Swakopmund but breeding in this area is yet to be confirmed (M. Boorman pers. comm. to R. B. Sherley in litt. 2016).  Approximately 80-90% of the breeding population is located on Mercury (2,019 pairs) and Ichaboe Islands (196 pairs), Namibia (Kemper et al. 2007, Ludynia et al. 2010, Ministry of Fisheries and Marine Resources [MFMR] unpubl. data).  The non-breeding range extends from just south of Hoanibmond (Hoanib River Mouth) south to Die Walle.  Several island populations in the west and north Cape Province have declined in recent years and seven former breeding localities have been vacated (Harrison et al. 1997).  The total number of breeding pairs fell from 7,600 in 1978-1980 to 5,750 by 1990 and to 2,800 by 2006 (Kemper et al. 2007).  The rate of decline was 4.3% per year over 16 years, equivalent to a decrease of 52.9% over three six-year generations.  Between 1993 and 1998, the Namibian breeding population is estimated to have declined by 68%, mainly due to a population collapse on Ichaboe Island after 1994-1995, mainly thought to result from food shortage, but other factors, e.g. predation and displacement by seals may also be a factor (Ludynia et al. 2010). Numbers on Ichaboe have since continued to decline, and although numbers have increased on Mercury Island and are currently stable (Ludynia et al. 2010); the total Namibian population in 2006 was 39% less than in 1993 (Kemper et al. 2007).

  

Countries occurrence:
Native:
Namibia; South Africa
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:402000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:45Continuing decline in number of locations:Yes
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The total breeding population was estimated at 2,500 pairs (5,000 mature individuals) in 2015.  This roughly equates to 7,500 individuals in total.

Trend Justification:  The overall rate of decline between 1990 and 2006 was 4.3% per year, equivalent to a decrease of 52.9% over three six-year generations (Kemper et al. 2007).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:5000Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:80-90

Habitat and Ecology [top]

Habitat and Ecology:

Behaviour  Adults are highly sedentary, and although individuals have been known to move up to 150 km, a mark-recapture survey recovered a large majority of adults within 10 km of the point of banding (Cooper 1981). Juveniles tend to disperse over larger distances, with adults and immatures tending to occur and forage in different areas (Kemper et al. 2007).  They are gregarious at colonies, although forage singly or in loose groups of up to 15 birds (del Hoyo et al. 1992, Johnsgard 1993).  Breeding activity occurs year round but is concentrated between May and October in the southern and central part of its range, and between November and April in the northern extension of its range (Crawford et al. 1999, MFMR unpubl. data).  Habitat  The distribution of this species broadly reflects that of kelp Ecklonia maxima beds and they are rarely found more than 10 km from shore (Cooper 1981).  They do not use estuaries or inland waters (Johnsgard 1993).  Breeding  They breed on sea-cliffs and rocky offshore islands (Nelson 2005), sometimes making use of walls or artificial platforms in close proximity to the sea (Cooper 1981, Sherley et al. 2012).  Their large size makes it difficult to take off, and this may influence and limit their choice of habitat (Nelson 2005).  Diet  The species has a varied diet including fish, crustaceans and cephalopods (Williams and Burger 1978, Cooper 1985, Ludynia et al. 2010).  Through much of their range they prefer to forage on the sea floor - especially among kelp beds at depths of 5 -15m - and prey mainly on klipfish (Clinidae) and blennies (Blenniidae) associated with the benthic habitat (Williams and Burger 1978).  In the northern part of the range, where the largest populations occur, they forage away from the kelp beds and the majority of their diet consists of Bearded Goby Sufflogobius bibarbatus typically foraged around 30-40 m depth (Williams and Burger 1978, Cooper 1981, Ludynia et al. 2010).  In the South African part of the range, commercially fished Cape Rock Lobster Jasus lalandi forms an important component of their diet (Cooper 1985, Sherley et al. 2016).  Breeding site  Nests are built on exposed rocks, walls or artificial platforms in close proximity to the sea (Cooper 1981).  The nest is very large (up to 6 kg) (Nelson 2005) and is constructed mainly from seaweed species with some sticks and feathers incorporated (Nelson 2005).  A clutch consists of one to three eggs, rarely four (R. Jones pers. comm. to R.B. Sherley et al. in litt. 2016), with a mean of two (Cooper 1987), but nests are often lost to rough seas (Sherley et al. 2012).  The young leave the nest before they are able to fly properly, and so are particularly vulnerable to predation and disturbance at this stage.  Age at first breeding is two to three years and average longevity of breeders is estimated at six years (Crawford et al. 1999, 2001).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):7.5
Movement patterns:Not a Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s):

The species is sensitive to human disturbance when breeding and will abandon its nest if approached, leaving the contents to be depredated by Kelp Gulls Larus dominicanus (Cooper 1987).  Human disturbance resulted in the loss of four colonies, and reductions in the populations at six others, between 1978 and 1997 (Du Toit et al. 2002).

Bank Cormorants could be limited by the availability of nesting habitat due to coastal development and competition with Cape Fur Seals Arctocephalus pusillus pusillus, which use the same type of habitat for hauling out or breeding (Crawford et al. 1999).  Cape Fur Seals Arctocephalus pusillus displaced 1,824 pairs from Mercury Island between 1978 and 1986 (Du Toit et al. 2002).  Seals have caused declines at three other colonies, and occur at 16 breeding localities, often severely restricting breeding space (Du Toit et al. 2002).  At some sites, Bank Cormorants breed on man-made structures, such as harbor walls.  These may not always represent high quality breeding habitat with nests potentially lost in large winter storms (Sherley et al. 2012).  An increase in frequency and amplitude of these events due to climate change, would have a strong impact on future breeding success of Bank Cormorants.  Similarly, Bank Cormorant chicks may be sensitive to heat waves (higher mortality), which could impact fecundity if such events increase owing to climate change (Sherley et al. 2012).  An increase in rainfall would also increase chick mortality through flooding of nests or hypothermia.

Changes in food availability may also continue to be a major threat.  A decreased abundance of Bearded Goby off central Namibia in 1994 led to large population reductions on Mercury and Ichaboe Islands; if goby are commercially harvested off Namibia, further significant declines are predicted in the species populations at Ichaboe and Mercury Islands (Du Toit et al. 2002).  Numbers of breeding birds have also reduced in areas of South Africa in line with reduced abundance of Cape Rock Lobster (Crawford et al. 2008) and the continued fishing of this major food source may be contributing to an ongoing decline in South Africa (Sherley et al. 2016).  A further impact of the commercial fishery for Cape Rock Lobster is incidental bycatch of birds in lobster traps (Cooper 1985).  Oil-spills are also a threat: the population at Robben Island was reduced by 25% after the Treasure oil-spill in 2000 (Du Toit et al. 2002), but numbers subsequently recovered (Sherley et al. 2012).  Habitat destruction, both through guano collection and coastal developments, has been a significant threat in the past (Du Toit et al. 2002).  Alien mammalian predators, allowed access through the construction of a land bridge, caused the extinction of the Lambert's Bay Bird Island colony (Du Toit et al. 2002).  Predation of eggs and chicks by Kelp Gull Larus dominicanus and Great White Pelican Pelecanus onocrotalus also impact populations (Harrison et al. 1997, Du Toit et al. 2002).  Avian cholera has affected other cormorant species in South Africa and could have catastrophic consequences for this species (Kemper et al. 2007). 

Conservation Actions [top]

Conservation Actions:

Conservation Actions Underway
In South Africa, it is protected by law and the terrestrial areas of the major islands where it breeds are national parks, nature reserves or otherwise protected.  However, some of the smaller breeding rocks are not protected.  Only 11 of the 45 (24%) extant breeding colonies have nature reserve status (Du Toit et al. 2002).  The colonies around Saldanha Bay, at Robben Island and at Stony Point are surrounded by at-sea areas of spatial protection, but all are smaller than the foraging range believed to be used by breeding adults (Ludynia et al. 2010, Sherley et al. 2016).  In Namibia, all breeding localities and key foraging ranges of breeding birds are included in the Namibian Islands Marine Protected Area (Currie et al. 2009, Ludynia et al. 2012).

Conservation Actions Proposed
Develop and implement management plans to protect breeding islands and cover the effects of human disturbance (Cooper 1981, Du Toit et al. 2002).  Protect sites accessible to humans from the mainland at low tide. Census the population regularly so that trends can be assessed.  Use colour-banding and biologging to better understand the species movements (Du Toit et al. 2002, Ludynia et al. 2010).  Develop and implement a sustainable fisheries plan for the Benguela Upwelling Region to avoid over-depletion of fish and lobster stocks (Du Toit et al. 2002), including a potential ban on lobster fisheries within key areas to reduce the risk of entanglement of benthic diving birds in the traps and competition for decreasing lobster resources (Ludynia et al. 2010, Sherley et al. 2016).  Take measures against the illegal cleaning of oil tanks at sea, which causes significant oil spills.  Develop a contingency plan for major oil spills off the coast of south-western Africa (Du Toit et al. 2002).  Improve the legal protection of Namibian offshore breeding sites (Du Toit et al. 2002).  Increase public awareness of the conservation problems facing this species (Du Toit et al. 2002).  The species can breed successfully on man-made structures (Sherley et al. 2012) and provision of additional, protected breeding habitat may be necessary in the future.

Amended [top]

Amended reason: Edited: Assessment rationale, Geographic Range, Population Justification, Habitat and Ecology, Threats, Conservation Actions proposed, Underway and in Place, Important Conservation Actions Needed and Research Needed. The estimated number of mature individual were altered. Added references and also added a new Facilitator and new Contributors.

Citation: BirdLife International. 2017. Phalacrocorax neglectus. (amended version published in 2016) The IUCN Red List of Threatened Species 2017: e.T22696766A112367141. . Downloaded on 24 June 2017.
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