Overview

Brief Summary

Biology

This sleek seabird forages typically less than ten kilometres from shore, in the cool waters of the north-flowing Benguela Current (6). It feeds in vast flocks of thousands of individuals on shoals of fish, often in association with terns, penguins and gannets. With a little leap clear of the water's surface, the Cape cormorant dives into the ocean (3), the surface feathers of its glossy plumage becoming easily soaked, reducing buoyancy and allowing the cormorant to descend more easily into the water. The inner feathers, however, remain waterproof and provide insulation in the chilly water (4). Each dive lasts for around 30 seconds, and each day there are two feeding bouts of around 30 minutes each (3). The Cape cormorant feeds principally on pilchard, as well as anchovies, sandeels, sardines, hake and, in smaller amounts, crabs, lobsters, mussels and squid (3). Breeding colonies of Cape cormorants are equally immense as the feeding flocks. Breeding may take place at any time of the year, but egg-laying primarily takes place between September and February. The male gathers dried seaweed, sticks, and floating ocean debris, such as plastic, netting and rope, from which the female constructs a nest, measuring about 30 centimetres across. Into this flimsy structure is laid a clutch of one to five eggs (most commonly two to three), which are laid at intervals of two to three days. Both the male and female share the task of incubating the eggs for 22 to 28 days, and when the young hatch, both bring food to the young (3). Parental care even extends to sheltering the newly hatched young from the sun, with adults observed standing with their wings outstretched with their backs to the sun (3). After five to six weeks, the young leave the nest to form small crèches of up to ten birds, and by nine weeks the young can fly (3). This fledgling population is very vulnerable to predators; Cape fur seals prey heavily on seabirds in southern Africa, and Cape cormorants are particularly susceptible to predation when they land on the waters surrounding breeding islands (7). Cape cormorants are known to live for up to nine years (3).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Description

The most distinctive feature of this southern African seabird is the bright orange-yellow patch of bare skin at the base of its bill, which sits in stark contrast against its glossy black plumage, tinged with a bluish-purple sheen (2) (3). The black bill, with a blue-grey base (3), has completely sealed nostrils (4), which means the Cape cormorant must breathe through its mouth, but is able to dive unhindered into the water in pursuit of prey. Like other Pelecaniformes (a group of large seabirds), the Cape cormorant has webbing between all four toes, making it a strong swimmer and proficient predator of fish (4). Its affinity for the sea is reflected in the common name, cormorant, which is a corruption of the French words corbeau marin, meaning sea crow (5). Juvenile Cape cormorants differ from adults in their dark brown plumage and pale underparts, but all ages have bright turquoise eyes (2) (3). Although said to be a fairly silent bird (2), the Cape cormorant does have a variety of vocalisations, including a repeated, low-pitched cluck made by the male during courtship and a hiss that escalates into a bark when threatened (3).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Distribution

Range Description

Phalacrocorax capensis is endemic to southern Africa, and breeds at 69 localities between Die Oase, Namibia, and Stag Island in eastern Cape Province, South Africa, although less than 2% of the population breeds east of Cape Agulhas (Barnes 2000). The global population numbered 247,000 pairs during 1977-1981. The population previously underwent fluctuations owing to variations in oceanographic conditions and consequently food supply (del Hoyo et al. 1992), but has since declined very rapidly. In South Africa, the population has decreased by 64% over 40 years, from 103,937 breeding pairs in 1978 to 37,408 breeding pairs in 2011 (Crawford et al. 2012, per T. Cook and J. Kemper in litt. 2013). Although fewer complete datasets are available from the 12 most important breeding localities in Namibia, the population trends are comparable to that of South Africa; a decline of 59.6% over 27 years, from 143,161 pairs in 1978/9, to 57,343 pairs in 2005/6 (Crawford et al. 2007). There are a further 2,000-2,600 pairs at Ilha dos Tigres in Angola, where the population trend is unknown.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Range

Coastal sw Namibia and s South Africa.

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Range

Found only in southern Africa, the Cape cormorant breeds along the coast of Namibia and the west coast of South Africa. Outside of the breeding season, Cape cormorants can be found as far north as the Congo River, and round to Durban on the east coast of South Africa (3) (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Physical Description

Diagnostic Description

Description

Length: 61-64 cm. Plumage: Black. Bare parts: iris turquoise; face and gular skin yellow to yellow-orange; bill legs and feet black; eyelids with bright blue beads. Habitat: coastal waters, estuaries. <388><393>
  • Brown, L.H., E.K. Urban & K. Newman (1982). The Birds of Africa, Volume I. Academic Press, London.
Creative Commons Attribution 3.0 (CC BY 3.0)

© WoRMS for SMEBD

Source: World Register of Marine Species

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Behaviour This species is mainly sedentary but shows extensive post-breeding dispersal to the north and east of its breeding range, with birds reaching the mouth of the river Congo and southern Mozambique (del Hoyo et al. 1992, Johnsgard 1993) and individuals moving up to 1,430km (Johnsgard 1993). It is thought that the birds follow the movements of schooling fish (Crawford and Shelton 1978, Johnsgard 1993). It is a highly gregarious species which breeds in vast colonies of up to 120,000 birds (Nelson 2005). Egg-laying occurs throughout much of the year, with a peak usually in September and October (del Hoyo et al. 1992, Johnsgard 1993), continuing to February in Namibia (Johnsgard 1993). However the level of breeding activity is highly dependent on food supply: breeding will fluctuate depending on prey availability (Berry et al. 1979, Crawford and Dyer 1995) and will even cease if prey becomes scarce (Johnsgard 1993, Nelson 2005). It usually forages in large aggregations, often co-operatively and in association with other seabirds (Johnsgard 1993, Nelson 2005), although solitary foraging is also known to occur (Johnsgard 1993). Birds may fly up to 40km to a feeding location (Nelson 2005).

Habitat This species is usually found in the Benguela current less than 10 km from the coast (del Hoyo et al. 1992), although it does occasionally range as far as 70km offshore. During both the breeding and the non-breeding seasons it inhabits cliffs and ledges on the mainland and on offshore islands (Nelson 2005). It is occasionally found in the brackish waters of coastal lagoons, estuaries and harbours (del Hoyo et al. 1992), but does not use these habitats for breeding. It occurs in highest densities in areas of suitable habitat near the recruitment grounds for pilchards (Clupeidae) and anchovies (Engraulidae.) (Crawford and Shelton 1978).

Diet
Its diet consists almost entirely of pelagic schooling fish, although it will occasionally take some invertebrates including crustaceans, molluscs and cephalopods (Rand 1960, Nelson 2005). South African Pilchards Sardinops ocellata and Cape Anchovies Engraulis japonicus capensis are often reported to be by far the most significant prey species throughout its range (Johnsgard 1993), but preferences appear to be subject to seasonal variation depending on the relative abundance of different fish species (Duffy et al. 1987, Crawford and Dyer 1995). Sandeels Ammodytes spp., Pelagic Gobies Sufflogobius bibarbatus and Maasbanker Trachurus trachurus may comprise the major food source under some circumstances (Cooper 1985, del Hoyo et al. 1992, Johnsgard 1993, Nelson 2005).

Breeding Site
Breeding occurs mainly on cliffs and ledges, and flat inland areas of offshore islands (Nelson 2005). Caves, estuarine sand islands, guano platforms and other artificial structures are also used as breeding sites (Johnsgard 1993, Nelson 2005). Nests are constructed from seaweed, sticks and stems, and occur in high density (roughly 3 nests per square metre) within large colonies (Nelson 2005). Normally two or three eggs are laid, although the clutch-size ranges from one to five. The incubation period is 22-28 days, and the chicks fledge after about nine weeks. Post-fledging care is provided for several weeks. The oldest ringed bird was at least nine years old (del Hoyo et al. 1992).


Systems
  • Terrestrial
  • Marine
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

The Cape cormorant is a marine bird, which breeds in enormous colonies in relatively remote and inaccessible habitats, including the flat areas of small offshore islands, coastal cliffs, artificial guano platforms and occasionally on other artificial structures (3) (6). Sometimes it enters harbours and estuaries (2)
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
A2bc+3bc+4bc

Version
3.1

Year Assessed
2013

Assessor/s
BirdLife International

Reviewer/s
Butchart, S.

Contributor/s
Thomas, R., Coetzee, R., Wanless, R., Kemper, J. & Cook, T.

Justification
This species has been uplisted to Endangered as key colonies in South Africa and Namibia are estimated to have undergone very rapid population declines over the past three generations. Declines are primarily believed to have been driven by collapsing pelagic fish stocks, but the species is also susceptible to oiling and avian cholera outbreaks. This trend currently shows no sign of reversing, and immediate conservation action is required to prevent further declines.


History
  • 2012
    Near Threatened
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Status

Classified as Near Threatened (NT) on the IUCN Red List (1).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Population

Population
The most recent available estimates are of 37,408 pairs in South Africa in 2011 (Crawford et al. 2012, per T. Cook and J. Kemper in litt. 2013), 57, 343 pairs in Namibia in 2005-2006 (Crawford et al. 2007) and 2,000-2,600 pairs in Angola, roughly equating to 190,000 mature individuals or 285,000 individuals in total. The global population was previously estimated to have numbered as many as 247,000 pairs during 1977-1981.

Population Trend
Decreasing
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Threats

Major Threats
Recent rapid declines are likely to be primarily driven by a shortage of good quality food and its vulnerability to avian cholera outbreaks (T. Cook and J. Kemper in litt. 2013). Declines in the late 20th century are attributed to commercial over-fishing of Sardinops ocellata, whose stocks crashed in the mid-1970s (del Hoyo et al. 1992). Large fluctuations in abundance are related to changes in availability of E. capensis, an important prey species, which may be part of a natural cycle. However, Engraulis capensis stocks have decreased off southern Africa (Barnes 2000). Given the influence of oceanographic conditions on prey availability and consequently the species's population, climate change may be a future threat.

Disease has also caused high mortality (Barnes 2000). In 2004, over 8,000 individuals on Dyer Island, South Africa, died due to an outbreak of avian cholera (Cape Times per R. Thomas in litt. 2004). Oil pollution is also a potential threat (Barnes 2000). In the past, guano mining caused considerable disturbance and declines (del Hoyo et al. 1992). Predation by Cape Fur Seal (Arctocephalus pusillus) on fledglings has increased as the seal has become more abundant owing to successful conservation measures (David et al. 2003), and has been found to represent a significant mortality factor for this species on Dyer Island, South Africa (Marks et al. 1997) and Ichaboe Island, Namibia (Du Toit et al. 2004). It probably affects the species throughout its range.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Cape cormorant populations have been affected by a number of factors over the years (8). The mining of guano caused considerable disturbance of breeding colonies in the past, resulting in declines, whereas more recently, overfishing of one of the cormorant's preferred prey species, the South African pilchard (Sardinops ocellata), impacted numbers of this species (6). Outbreaks of disease in Cape cormorant populations has also had devastating affects, with more than 14,500 cormorants dying in 1991 from avian cholera on eight islands off western South Africa (9), and a further 8,000 individuals perishing on Dyer Island from an outbreak of the same disease in 2004 (6). In addition, oil spills within the range of the Cape cormorant is a continual potential threat (6). Although many fluctuations seen in Cape cormorant populations are due to natural cycles in the availability of prey, some recent declines of certain prey species, such as the Cape anchovy (Engraulis capensis), are of concern (6) (8). Given the close relationship between Cape cormorant populations and the availability of their prey, global climate change, which could affect ocean conditions and therefore prey distribution and availability, may have serious consequences for this seabird (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Management

Conservation Actions

Conservation Actions
Conservation Actions Underway
Following past declines caused by guano mining, guano platforms have been constructed to increase the extent of suitable breeding grounds (del Hoyo et al. 1992). Strict measures were put in place on Dyer Island in 2004, to control an outbreak of avian cholera (Cape Times per R. Thomas in litt. 2004). A selective cull of Cape Fur Seals was instigated in 1993, with immediate but short-term effect on seabird mortality rates (David et al. 2003).

Conservation Actions Proposed
Conduct simultaneous surveys at all colonies to obtain an up-to-date population estimate. Monitor population trends through regular surveys (Barnes 2000). Monitor trends in the stocks of prey species. Enforce measures to prevent and mitigate oil-spills. Develop emergency plans for the control of disease.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Conservation

Although not yet considered to be at risk of extinction (1), the Cape cormorant is listed on Annex II of the African-Eurasian Waterbird Agreement, which requires countries party to the agreement to engage in a wide range of conservation actions. While South Africa has signed to the agreement, Namibia currently has not (10). As a result of guano mining causing declines in the Cape cormorant in the past, guano platforms were constructed to increase the area of suitable breeding ground available (6). In addition, measures were implemented on Dyer Island in 2004 to control the outbreak of avian cholera. This involves the prompt removal of carcasses of birds which have been believed to been killed by avian cholera, which hinders the spread of this highly contagious disease (6) (11). Further measures, including monitoring trends in stocks of prey species and enforcing measures to prevent oil spills, have been recommended to ensure that this distinctive marine bird does not become threatened (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Average rating: 2.5 of 5

Wikipedia

Cape Cormorant

Cape Town, South Africa

The Cape cormorant or Cape shag (Phalacrocorax capensis) is a bird endemic to the southwestern coasts of Africa.

It breeds from Namibia south to southern Cape Province. In the nonbreeding season, it may be found as far north as the mouth of the Congo, and also extends up the east coast of South Africa as far as Mozambique. In the 1970s, the breeding population was estimated as over 1 million in Namibia alone. However, the IUCN now classifies it as "Endangered" due to a very rapid decline in the population over the last three generations.[1]

The Cape cormorant is an almost entirely glossy black bird, though in breeding condition it has a purplish tinge and a few white plumes on head, neck, and cloacal areas. Its gular skin is a deep orangey yellow; unusually for a cormorant, its lores are feathered. The bird's wing is about 240–280 mm in extent, and it weighs 800-1,600 grams, with little sexual dimorphism.

Cape shags commonly forage in flocks, taking schooling fish from mid-water, such as pilchards, anchovies, and sandeels. Its prey are typically much smaller than those of the sympatric bank cormorant. Their major predators are black-backed jackals, which take the occasional adult while it is roosting, and nest-site predators such as great cormorants, eastern great white pelicans, and kelp gulls.

Like a number of other related cormorant species, the Cape cormorant is placed by some authorities (e.g. Johnsgaard) in the genus Leucocarbo.

References[edit]

  • Johnsgaard, P. A. (1993). Cormorants, darters, and pelicans of the world. Washington DC: Smithsonian Institution Press. ISBN 1-56098-216-0
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Average rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!