Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Behaviour This species is sedentary (del Hoyo et al. 1992) but often makes local movements in semi-arid areas (Brown et al. 1982) and disperses during the rains (del Hoyo et al. 1992). It breeds all year round in East Africa, but elsewhere breeding peaks mostly late in the rains or in the dry season (del Hoyo et al. 1992). The species nests solitarily (del Hoyo et al. 1992) and usually occurs in pairs or in small groups of 8-10 individuals outside of the breeding season, sometimes also occurring in social groups of more than 50 (Brown et al. 1982). Habitat The species occupies a wide variety of habitats (del Hoyo et al. 1992) from forest to semi-desert, wherever water is available (Brown et al. 1982). It is commonest in well-watered savanna or woodland and less common in forest, showing a general preference for permanent waters although it will also use temporary wetlands in arid areas (Brown et al. 1982). The species forages in shallow water along sandbanks, in reedbeds or in floating vegetation (Brown et al. 1982) and requires trees (e.g. Khaya senegalensis) to nest and roost in (Brown et al. 1982, del Hoyo et al. 1992). Suitable habitats include the banks of large rivers and lakes (Brown et al. 1982, del Hoyo et al. 1992), marshes, dams, temporary seasonal ponds (Brown et al. 1982), aquaculture ponds, irrigation schemes and estuaries as well as rocky coasts in Tanzania (del Hoyo et al. 1992). Diet Its diet consists predominantly of amphibians (especially Xenopus spp. adults and tadpoles) and small fish as well as crustaceans, worms and insects (del Hoyo et al. 1992). Breeding site The nest is an elaborate hollow structure of sticks usually built in a fork of a tree (del Hoyo et al. 1992) overhanging water, but alternatively built on cliff ledges, rock columns, on the ground or on sandbanks (Brown et al. 1982). The species shows a preference for nesting in dead trees standing in water and usually roosts in or near its nest (Brown et al. 1982).

Systems
  • Terrestrial
  • Freshwater
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Scopus umbretta

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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Population

Population Trend
Stable
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Threats

Major Threats
The species is potentially threatened by a deterioration in wetland water quality caused by the excessive use of pesticides (del Hoyo et al. 1992). Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).
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Wikipedia

Hamerkop

The hamerkop (Scopus umbretta), also known as hammerkop, hammerkopf, hammerhead, hammerhead stork, umbrette, umber bird, tufted umber, or anvilhead, is a medium-sized wading bird 56 centimetres (22 in) in length with a weight of 470 grams (17 oz). The shape of its head with a long bill and crest at the back is reminiscent of a hammer, hence its name. It ranges from Africa, Madagascar to Arabia, in wetlands of a wide variety, including estuaries, lakesides, fish ponds, riverbanks and rocky coasts in Tanzania. The hamerkop, which is a sedentary bird that often show local movements, is not globally threatened and is locally abundant in Africa and Madagascar.[2]

Taxonomy and systematics[edit]

The hamerkop is usually included in the Ciconiiformes, but might be closer to the Pelecaniformes.[3] It constitutes a family (Scopidae) and genus (Scopus) all on its own because of its unique characteristics.[2]

Subspecies[edit]

There are two subspecies, Scopus umbretta umbretta and Scopus umbreta minor.[2]

Description[edit]

The subspecies S. u. minor is smaller and darker.

Its plumage is a drab brown with purple iridescence on the back (the subspecies S. u. minor is darker).[2] The bill is long, flat, and slightly hooked.[2] The neck and legs are shorter than those of most of the Ciconiiformes. The hamerkop has, for unknown reasons, partially webbed feet.[4] The middle toe is comb-like (pectinated) like a heron's.[2] Its tail is short and its wings are big, wide, and round-tipped; it soars well. When it does so, it stretches its neck forward like a stork or ibis, but when it flaps, it coils its neck back something like a heron.[4]

Vocalisations include cackles and a shrill call given in flight. Hamerkops are mostly silent except when in groups.[4]

Distribution and habitat[edit]

The hamerkop occurs in Africa south of the Sahara, Madagascar and coastal south-west Arabia in all wetland habitats, including irrigated land such as rice paddies, as well as in savannahs and forests. Most are sedentary within their territories, which are held by pairs, but some migrate into suitable habitat during the wet season only. Whenever new bodies of water are created, such as dams or canals, hamerkops quickly move in.[4]

Behaviour and ecology[edit]

Individual collecting nesting material at Lake Naivasha, Kenya

The hamerkop's behaviour is unlike other birds. One unusual feature is that up to ten birds join in "ceremonies" in which they run circles around each other, all calling loudly, raising their crests, fluttering their wings. Another is "false mounting", in which one bird stands on top of another and appears to mount it, but they may not be mates and do not copulate.[2][4]

Breeding[edit]

Partial view of nest. A piece of bright-coloured plastic is visible in the center.
Full view of nest built in the fork of an Acacia tree

The strangest aspect of hamerkop behaviour is the huge nest, sometimes more than 1.5 metres (4 ft 11 in) across, comprising perhaps 10,000 sticks and strong enough to support a man's weight. The birds decorate the outside with any bright-coloured objects they can find. When possible, they build the nest in the fork of a tree, often over water, but if necessary they build on a bank, a cliff, a human-built wall or dam, or on the ground. A pair starts by making a platform of sticks held together with mud, then builds walls and a domed roof. A mud-plastered entrance 13–18 centimetres (5.1–7.1 in) wide in the bottom leads through a tunnel up to 60 centimetres (24 in) long to a nesting chamber big enough for the parents and young.[4]

These birds are compulsive nest builders, constructing three to five nests per year whether they are breeding or not. Barn owls and eagle owls may force them out and take over the nests, but when the owls leave, the hamerkops may reuse the nests.[2] Snakes, small mammals such as genets, and various birds live in abandoned nests, and weaver birds, starlings, and pigeons may attach their nests to the outside.[4]

At the finished nest, a pair gives displays similar to those of the group ceremonies and mates, often on top of the nest. The clutch consists of three to seven eggs which start white but soon become stained. Both sexes incubate for 28 to 30 days. Both feed the young, often leaving them alone for long times; this unusual habit for wading birds may be made possible by the thick nest walls. The young hatch covered with grey down. By 17 days after hatching, their head and crest plumage is developed, and in a month, their body plumage. They leave the nest at 44 to 50 days but roost in it at night until about two months after hatching.[4]

Food and feeding[edit]

Hamerkops feed during the day, often taking a break at noon to roost. They normally feed alone or in pairs. The food is typical of long-legged wading birds, and the most important is amphibians. They also eat fish, shrimp, insects and rodents. They walk in shallow water looking for prey, shuffling one foot at a time on the bottom or suddenly opening their wings to flush prey out of hiding.[4] The same shuffling technique is used to locate food in middens of fish remains.

In culture[edit]

There are many legends about the hamerkop. In some regions, people state that other birds help it build its nest.[4] The ǀXam informants of Wilhelm Bleek said that when a hamerkop flew and called over their camp, they knew that someone close to them had died.[5]

It is known in some cultures as the lightning bird, and the Kalahari Bushmen believe or believed that being hit by lightning resulted from trying to rob a hamerkop's nest. They also believe that the inimical god Khauna would not like anyone to kill a hamerkop.[6] According to an old Malagasy belief, anyone who destroys its nest will get leprosy, and a Malagasy poem calls it an "evil bird".[7] Such beliefs have given the bird some protection.[8]

Scopus, a database of abstracts and citations for scholarly journal articles, received its name in honour of this bird, as the hamerkop is renowned for its superior navigation skills.

References[edit]

  1. ^ BirdLife International (2012). "Scopus umbretta". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ a b c d e f g h del Hoyo, J. Elliott, A. & Sargatal, J. (editors). (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions. ISBN 84-87334-10-5
  3. ^ Van Tuinen, Marcel; Butvill, Dave Brian; Kirsch, John A. W. and Hedges, S. Blair (2001). "Convergence and divergence in the evolution of aquatic birds" (PDF). Proceedings of the Royal Society of London 26 (8): 1345–1350. 
  4. ^ a b c d e f g h i j Shukla, Arvind N.; Tyagi, Rajiv (2004). Encyclopaedia of Birds. Anmol Publications PVT. LTD. p. 234. ISBN 81-261-0967-X. Retrieved September 25, 2008. 
  5. ^ Schapera, Isaac (1965). The Khoisan Peoples of South Africa. G. Routledge and Paul. p. 167. Retrieved September 22, 2008. 
  6. ^ Schapera op. cit., p. 189
  7. ^ Fox, Leonard (1990). Hainteny: The Traditional Poetry of Madagascar. Bucknell University Press. pp. 261, 422. ISBN 0-8387-5175-X. 
  8. ^ Child, Graham; Chitsike, Langford (August 31, 2000). "'Ownership' of Wildlife". In Prins, Herbert H. T.; Grootenhuis, Jan Geu; Dolan, Thomas T., editors. Wildlife Conservation by Sustainable Use. Netherlands: Springer. p. 253. ISBN 0-412-79730-5. 
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