|Scientific Name:||Phalacrocorax neglectus|
|Species Authority:||(Wahlberg, 1855)|
|Red List Category & Criteria:||Endangered A2ace+3ce+4ace ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
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, and severe food shortages. A catastrophic oil-spill in 2000 also affected some colonies. Despite the removal of cape fur seals on one island, the overall population continues to decline.
|Range Description:||Phalacrocorax neglectus breeds at 45 localities between Hollam's Bird Island, Namibia, and Quoin Rock, South Africa. About 80-90% of the breeding population is located on Mercury (1,840 pairs) and Ichaboe Islands, Namibia (Kemper et al. 2007, Ludynia et al. 2010). The non-breeding range extends from just south of Hoanibmond 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).|
Native:Namibia; South Africa
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total breeding population was estimated at 2,800 pairs (5,600 mature individuals) in 2006. This roughly equates to 8,400 individuals in total.|
|Habitat and Ecology:||Behaviour Adults are highly sedentary, and although individuals have been known to move up to 150 km, a capture-recapture survey recovered a large majority of adults within 10km 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). It is a gregarious species, breeding and roosting in colonies of up to 100 pairs (del Hoyo et al. 1992), although it forages 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 part of its range, and between November and April in the central Namibian colonies at the northern extension of its range (Crawford et al. 1999). Habitat The distribution of this species broadly reflects that of kelp Ecklonia maxima beds and it is rarely found more than 10 km from shore (Cooper 1981). It does not use estuaries or inland waters (Johnsgard 1993). Breeding It breeds 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). Its large size makes it difficult to take off, and this may influence and limit its choice of habitat (Nelson 2005). Diet The species has a varied diet which consists principally of marine fish (Williams and Burger 1978) but includes some invertebrates, particularly crustaceans including the commercially fished Cape Rock Lobster, Jasus lalandi (Cooper 1985) (particularly in the South African part of its range [Ludynia et al. 2010]), and various cephalopods. Through most of its range the species prefers to forage on the sea floor - especially among kelp beds at depths of 5 -15m - and preys mainly on klipfish (Clinidae) and blennies (Blenniidae) which are associated with that habitat (Williams and Burger 1978). However in the northern part of its range where the largest populations occur, the species forages away from the kelp beds and the majority of its diet consists of Pelagic Gobies Sufflogobius bibarbatus(Williams and Burger 1978, Cooper 1981) typically foraged around 30-40m depth (Ludynia et al. 2010). 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 6kg) (Nelson 2005) and constructed mainly from green seaweed with some sticks and feathers incorporated (Nelson 2005). A clutch consists of one to three eggs, with a mean of two, but nests are often lost to rough seas (Nelson 2005). 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 (Du Toit et al. 2002).|
Human disturbance resulted in the loss of four colonies, and reductions in the populations at six others, between 1978 and 1997. Cape Fur Seals Arctocephalus pusillus displaced 1,824 pairs from Mercury Island between 1978 and 1986. Despite expulsion of most seals, the colony has recovered poorly. Seals have caused declines at three other colonies, and occur at 16 breeding localities, often severely restricting breeding space (Du Toit et al. 2002). A decreased abundance of 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's 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 Lobsters (Ludynia et al. 2010) and the decline of this major food source may be another contributing factor (Wanless 2010). A further impact of the commercial fishery for Cape Rock Lobsters is birds being caught incidentally in lobster pots (Kemper et al. 2007). Substantial decreases on Malgas and Dassen Islands may also have been food-related. Oil-spills are also a threat: 25% of the population of Robben Island was lost due to the Treasure oil-spill in 2000 (Du Toit et al. 2002). Habitat destruction, both through guano collection and coastal developments, has been a significant threat in the past and guano collection contines on Ichaboe island (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 is also a problem (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 Underway
In South Africa, it is protected by law and the major islands where it breeds are national parks, nature reserves or otherwise protected. However, some of the smaller breeding rocks are not protected and in fact only 11 of the 45 (24%) extant breeding colonies have nature reserve status (Du Toit et al. 2002). In Namibia, breeding islands are administered by the Ministry of Fisheries and Marine Resources, but only three are staffed. Conservation Actions Proposed
Develop and implement management plans to protect breeding islands and cover the effects of introduced predators, alien plant control and 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 and use colour-banding to better understand the species movements (Du Toit et al. 2002). 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 (Ludynia et al. 2010). 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).
Barnes, K. N. 2000. The Eskom Red Data Book of birds of South Africa, Lesotho and Swaziland. BirdLife South Africa, Johannesburg.
Cooper, J. 1981. Biology of the Bank Cormorant, Part 1: distribution, population size, movements and conservation. Ostrich 52: 208-215.
Crawford, R.J.M., Dyer, B.M., Cordes, I. and Williams, A.J. 1999. Seasonal pattern of breeding, population trend and conservation status of bank cormorants Phalacrocorax neglectus off south western Africa. Biological Conservation 87(1): 49-58.
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.
Du Toit, M.; Boere, G. C.; Cooper, J.; de Villiers, M. S.; Kemper, J.; Lenton, B.; Petersen, S. L.; Simmons, R. E.; Whittington, P. A.; Byers, O. P. 2002. Conservation assessment and management plan for southern African seabirds.
Harrison, J. A.; Allan, D. G.; Underhill, L. G.; Herremans, M.; Tree, A. J.; Parker, V.; Brown, C. J. 1997. The atlas of southern African birds. BirdLife South Africa, Johannesburg.
IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).
Johnsgard, P. A. 1993. Cormorants, darters, and pelicans of the world. Smithsonian Institution Press, Washington.
Kemper, J.; Underhill, L. G.; Crawford, R. J. M.; Kirkman, S. P. 2007. Revision of the conservation status of seabirds and seals breeding in the Benguela Ecosystem. In: Kirkman, S. P. (ed.), Final Report of the BCLME (Benguela Current Large Marine Ecosystem), pp. 325-342.
Ludynia, K., Jones, R., Kemper, J., Garthe, S. and Underhill, L.G. 2010. Foraging behaviour of bank cormorants in Namibia: implications for conservation. Endangered Species Research 12: 31-40.
Nelson, J. B. 2005. Pelicans, cormorants and their relatives. Pelecanidae, Sulidae, Phalacrocoracidae, Anhingidae, Fregatidae, Phaethontidae. Oxford University Press, Oxford, U.K.
Wanless, R. 2010. The banks are collapsing. Africa - Birds & Birding 15(5): 70.
Williams, A.J. and Burger, A.E. 1978. The ecology of the prey of Cape and Bank Cormorants. Cormorant 4: 28-29.
|Citation:||BirdLife International 2012. Phalacrocorax neglectus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.|
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