African fish eagle

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African fish eagle
African fish eagle (Haliaeetus vocifer) Ethiopia.jpg
Lake Zway, Ethiopia
African Fish Eagle AdF.jpg
Lake Mburo, Uganda

Least Concern (IUCN 3.1)[1]
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Haliaeetus
Species:
H. vocifer
Binomial name
Haliaeetus vocifer
(Daudin, 1800)
In The Gambia, December 2021

The African fish eagle (Haliaeetus vocifer)[2] or the African sea eagle, is a large species of eagle found throughout sub-Saharan Africa wherever large bodies of open water with an abundant food supply occur. It is the national bird of Namibia and Zambia. As a result of its large range, it is known in many languages.[3] Examples of names include: nkwazi in Chewa, aigle pêcheur in French,[4] hungwe in Shona, inkwazi in isiZulu, and 'ntšhu' (pronounced "ntjhu") in Northern Sotho. This species may resemble the bald eagle in appearance; though related, each species occurs on different continents, with the bald eagle being resident in North America.

Taxonomy[]

The African fish eagle is a species placed in the genus Haliaeetus (sea eagles). Its closest relative appears to be the critically endangered Madagascar fish eagle (H. vociferoides). Like all sea eagle species pairs, this one consists of a white-headed species (the African fish eagle) and a tan-headed one (Madagascar fish eagle). These are an ancient lineage of sea eagles, and as such, have dark talons, beaks, and eyes[5] Both species have at least partially white tails even as juveniles. The scientific name is derived from Haliaeetus, New Latin for "sea eagle" (from the Ancient Greek haliaetos), and vocifer is derived from its original genus name, so named by the French naturalist François Levaillant, who called it 'the vociferous one'.[6]

Description[]

The African fish eagle is a large bird. The female, at 3.2–3.6 kg (7.1–7.9 lb) is larger than the male, at 2.0–2.5 kg (4.4–5.5 lb). This is typical sexual dimorphism in birds of prey. Males usually have wingspans around 2 m (6.6 ft), while females have wingspans of 2.4 m (7.9 ft). The body length is 63–75 cm (25–29.5 in). The adult is very distinctive in appearance with a mostly brown body with a white head like the bald eagle and large, powerful, black wings. The head, breast, and tail of African fish eagles are snow white, with the exception of the featherless face, which is yellow. The eyes are dark brown in colour. The hook-shaped beak, ideal for a carnivorous lifestyle, is yellow with a black tip. The plumage of the juvenile is brown in colour, and the eyes are paler compared to the adult. The feet have rough soles and are equipped with powerful talons to enable the eagle to grasp slippery aquatic prey. While this species mainly subsists on fish, it is opportunistic and may take a wider variety of prey such as waterbirds. Its distinctive cry is, for many, evocative of the spirit or essence of Africa.[7][8][9] The call, shriller when uttered by males, is a weee-ah, hyo-hyo or a heee-ah, heeah-heeah.[8]

Distribution and habitat[]

This species is still quite common near freshwater lakes, reservoirs, and rivers, although they can sometimes be found near the coast at the mouths of rivers or lagoons. African fish eagles are indigenous to sub-Saharan Africa, ranging over most of continental Africa south of the Sahara Desert. Several examples of places where they may be resident include the Orange River in South Africa and Namibia, the Okavango Delta in Botswana, and Lake Malawi bordering Malawi, Tanzania, and Mozambique. The African fish eagle is thought to occur in substantial numbers around the locations of Lake Victoria and other large lakes in central Africa, particularly the Rift Valley lakes.[10] This is a generalist species, requiring only open water with sufficient prey and a good perch, as evidenced by the number of habitat types in which this species may be found, including grassland, swamps, marshes, tropical rainforest, fynbos, and even desert-bordering coastlines,[11] such as that of Namibia. The African fish eagle is absent from arid areas with little surface water.

Reproduction[]

African fish eagles breed during the dry season, when water levels are low. They are believed to mate for life.[12][13] Pairs often maintain two or more nests, which they frequently reuse. Because nests are reused and built upon over the years, they can grow quite large, some reaching 2 m (6.0 ft) across and 1.2 m (3.9 ft) deep. The nests are placed in a large tree and are built mostly of sticks and other pieces of wood.

The female lays one to three eggs, which are primarily white with a few reddish speckles. Incubation is mostly done by the female, but the male incubates when the female leaves to hunt. Incubation lasts for 42 to 45 days before the chicks hatch. Siblicide does not normally occur in this taxon, and the parents often successfully rear two or three chicks.[14] Chicks fledge around 70 to 75 days old. Postfledgling dependence lasts up to three months, whereafter the juveniles become nomadic, and may congregate in groups away from territorial adults.[14] Those that survive their first year have a life expectancy of some 12 to 24 years.[12]

Diet[]

African fish eagle carrying off a catfish in Lake Baringo, Kenya
An African fish eagle feeding on its prey, likely a Mudfish Labeo sp., at the S3 Road West of Skukuza, Kruger National Park, Mpumalanga, South Africa

The African fish eagle feeds mainly on fish, which it swoops down upon from a perch in a tree, snatching the prey from the water with its large, clawed talons. The eagle then flies back to its perch to eat its catch.

Like other sea eagles, the African fish eagle has structures on its toes called spiricules that allow it to grasp fish and other slippery prey. The osprey, a winter visitor to Africa, also has this adaptation. Should the African fish eagle catch prey over ten times their own body weight, it is too heavy to allow the eagle to get lift, so it instead drags the fish across the surface of the water until it reaches the shore. If it catches a fish too heavy to allow the eagle to sustain flight, it will drop into the water and paddle to the nearest shore with its wings. The African fish eagle is known to steal the catch of other bird species (such as goliath herons) [15] in a behaviour known as kleptoparasitism. It also feeds on birds, especially waterbirds such as ducks, greater and lesser flamingos, small turtles and terrapins, baby crocodiles, lizards, frogs, and carrion. Occasionally, it may even carry off mammalian prey, such as hyraxes and monkeys.[15] It has also been observed feeding on domestic fowl (chickens).

Relationship with humans[]

Conservation[]

This species is listed as least concern by the IUCN.[1] The estimated population size is about 300,000 individuals with a distribution area of 18,300,000 km2.[16]

Heraldry[]

In the form of the Zimbabwe Bird, it is the national bird of Zimbabwe and appears on the Zimbabwean flag. The bird also figures in the coat of arms of Namibia, Zambia, and South Sudan, and on the Zambian flag.

Gallery[]

References[]

  1. ^ a b BirdLife International (2020). "Haliaeetus vocifer". IUCN Red List of Threatened Species. 2020: e.T22695115A174556979. doi:10.2305/IUCN.UK.2020-3.RLTS.T22695115A174556979.en. Retrieved 12 November 2021.
  2. ^ Etymology: Haliaeetus, New Latin for "sea eagle", vocifer, from Latin vox, "voice" + -fer, one who bears something, in allusion to the conspicuous yelping calls. These are, when sitting, given with the head fully thrown to the back, a peculiarity found among sea eagles only in this and the Madagascar species.
  3. ^ "African Fish Eagle (Haliaeetus vocifer) - Birds.com: Online Birds Guide with Facts, Articles, Videos, and Photos". Birds.com. Retrieved 2012-12-12.
  4. ^ "African Fish Eagle videos, photos and facts - Haliaeetus vocifer". ARKive. Archived from the original on 2012-12-27. Retrieved 2012-12-12.
  5. ^ Wink, M.; Heidrich, P.; Fentzloff, C. (1996). "A mtDNA phylogeny of sea eagles (genus Haliaeetus) based on nucleotide sequences of the cytochrome b gene" (PDF). Biochemical Systematics and Ecology. 24 (7–8): 783–791. doi:10.1016/S0305-1978(96)00049-X.
  6. ^ Fourie, Pieter J (2010). Media Studies: Policy, Management and Media Representation. Juta and Company Ltd. p. 370. ISBN 978-0-7021-7675-3.
  7. ^ "African fish eagle - Wilkinson's World". www.wilkinsonsworld.com. Retrieved 18 April 2018.
  8. ^ a b "Fish Eagle". The Booking Company. Archived from the original on 2012-03-25. Retrieved 2012-12-12.
  9. ^ "Art Of The Wild by Roger Brown.: Cry of the African Fish Eagle". Artofthewildrogerbrown.blogspot.com. 2011-05-10. Retrieved 2012-12-12.
  10. ^ "African Fish Eagle {Haliaeetus vocifer}". Sa-venues.com. Retrieved 2012-12-12.
  11. ^ "BBC Nature - African fish eagle videos, news and facts". Bbc.co.uk. 1970-01-01. Retrieved 2012-12-12.
  12. ^ a b Wildscreen. "African Fish Eagle". eol.org. Encyclopedia of Life. Retrieved 11 April 2016.
  13. ^ Orban, David. "Haliaeetus vocifer African fish eagle". Animal Diversity Web. University of Michigan. Retrieved 11 April 2016.
  14. ^ a b Botha, André; et al. (2012). Eagles and Farmers (PDF). ewt.org.za. Birds of Prey Programme, Endangered Wildlife Trust. ISBN 978-0-620-11147-8. Archived from the original (PDF) on 18 February 2017. Retrieved 11 April 2016.
  15. ^ a b "The African fish eagle". Encounter.co.za. Archived from the original on 2013-01-17. Retrieved 2012-12-12.
  16. ^ "African Fish Eagle (Haliaeetus vocifer) - BirdLife species factsheet". Birdlife.org. Retrieved 2012-12-12.

External links[]

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