The hamerkop (''Scopus umbretta'') is a medium-sized wading

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

. It is the only living species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Scopus'' and the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Scopidae. The species and family was long thought to sit with the

Ciconiiformes Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family called Ciconiidae, and make up the order Ciconiiformes . Ciconiiformes previously included a number of other families, such as herons a ...

but is now placed with the

Pelecaniformes The Pelecaniformes are an order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such n ...

, and its closest relatives are thought to be the pelicans and the

shoebill The shoebill (''Balaeniceps rex'') also known as the whalebill, whale-headed stork or shoe-billed stork, is a very large long-legged wading bird. It derives its name from its enormous shoe-shaped bill. It has a somewhat stork-like overall form ...

. The shape of its head with a long bill and crest at the back is reminiscent of a hammer, which has given this species its name after the

Afrikaans Afrikaans (, ) is a West Germanic language that evolved in the Dutch Cape Colony from the Dutch vernacular of Holland proper (i.e., the Hollandic dialect) used by Dutch, French, and German settlers and their enslaved people. Afrikaans gra ...

word for hammerhead. It is a medium-sized waterbird with brown plumage. It is found in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

and

Arabia The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plat ...

, living in a wide variety of

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

s, including

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

, lakesides, fish ponds, riverbanks, and rocky coasts. The hamerkop is a

sedentary Sedentary lifestyle is a lifestyle type, in which one is physically inactive and does little or no physical movement and or exercise. A person living a sedentary lifestyle is often sitting or lying down while engaged in an activity like soci ...

bird that often shows local movements. The hamerkop takes a wide range of prey, mostly fish and amphibians, but shrimps, insects and rodents are taken too. Prey is usually hunted in shallow water, either by sight or touch, but the species is adaptable and will take any prey it can. The species is renowned for its enormous nests, several of which are built during the breeding season. Unusually for a wading bird the nest has an internal nesting chamber where the eggs are laid. Both parents incubate the eggs, and raise the chicks. The species is not globally threatened and is locally abundant in Africa and Madagascar, and the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...

(IUCN) has assessed it as being of

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

Taxonomy and systematics

The hamerkop was first described by the French zoologist

Mathurin Jacques Brisson Mathurin Jacques Brisson (; 30 April 1723 – 23 June 1806) was a French zoologist and natural philosopher. Brisson was born at Fontenay-le-Comte. The earlier part of his life was spent in the pursuit of natural history; his published works ...

in 1760 in his landmark ''Ornithologia'' which was published two years after the tenth edition of

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

' '' Systema Naturae''. The species was subsequently described and illustrated by French polymath Comte de Buffon. When the German naturalist Johann Friedrich Gmelin revised and expanded

's '' Systema Naturae'' in 1788 he included the hamerkop and cited the earlier authors. He placed the species in the

''Scopus'' that had been introduced by Brisson and coined the binomial name ''Scopus umbretta''. Brisson's names for bird genera were widely adopted by the ornithological community despite the fact that he did not use Linnaeus' binomial system. The International Commission on Zoological Nomenclature ruled in 1911 that Brisson's genera were available under the

International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the ...

, so Brisson is considered to be the genus authority for the hamerkop. The generic name, ''Scopus'', is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

''skia'' for shadow. The specific name ''umbretta'' is modified from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for umber or dark brown. The hamerkop is sufficiently distinct to be placed in its own family, although the relationships of this species to other families has been a longstanding mystery. The hamerkop was usually included in the

, but is now thought to be closer to the

. Recent studies have found that its closest relatives are the pelicans and

. Although the hamerkop is the only living member of its family, one extinct species is known from the fossil record. ''

Scopus xenopus ''Scopus xenopus'' is an extinct species of hamerkop that lived during the Pliocene of South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of c ...

'' was described by ornithologist

Storrs Olson Storrs Lovejoy Olson (April 3, 1944 – January 20, 2021) was an American biologist and ornithologist who spent his career at the Smithsonian Institution, retiring in 2008. One of the world's foremost avian paleontologists, he was best known ...

in 1984 based on two bones found in

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58tarsus that the species may have been more aquatic. The hamerkop is also known as the hammerkop, hammerkopf, hammerhead, hammerhead stork, umbrette, umber bird, tufted umber, or anvilhead.

Subspecies

Two subspecies are recognized - the widespread nominate race ''S. u. umbretta'' and the smaller of West African ''S. u. minor'', described by

George Latimer Bates George Latimer Bates (March 21, 1863, Abingdon, Illinois US – January 31, 1940 Chelmsford UK), LL.D., M.B.O.U. was an American naturalist. Bates studied at Knox College, Galesburg and at the Chicago Theological Seminary and in 1895 visited W ...

in 1931. Two other subspecies have been proposed. ''S. u. bannermani'' of south west Kenya is usually lumped with the nominate race. Birds in Madagascar have been suggested to be distinct, in which case they would be placed in the subspecies ''S. u. tenuirostris''. That proposed subspecies was described by

Austin L. Rand Austin Loomer Rand (16 December 1905 – 6 November 1982) was a Canadian zoologist. He was born in Kentville, Nova Scotia in 1905 and grew up in nearby Wolfville, where he was mentored by the noted local ornithologist Robie W. Tufts. He received a ...

in 1936. It has also been suggested that birds near the

Kavango River The Okavango River (formerly spelled Okovango or Okovanggo), Also known as the Cubango River, is a river in southwest Africa. It is the fourth-longest river system in southern Africa, running southeastward for . It begins at an elevation of in ...

in Namibia may be distinct, but no formal description has been made.

Description

The hamerkop is a medium-sized waterbird, standing high and weighing , although the subspecies ''S. u. minor'' is smaller. Its plumage is a drab brown with purple iridescence on the back; ''S. u. minor'' is darker. The tail is faintly barred with darker brown. The sexes are alike and fledglings resembled adults. The bill is long, , and slightly hooked at the end. It resembles the bill of a shoebill, and is quite compressed and thin, particularly at the lower half of the mandible. The bill is brown in young birds, but becomes black by the time a bird fledges. Hamerkop (Scopus umbretta)3

The neck and legs are proportionately shorter than those of similar looking Pelecaniformes. The bare parts of the legs are black and the legs are feathered only to the upper part of the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

. The hamerkop has, for unknown reasons, partially webbed feet. The middle toe is comb-like (pectinated) like a heron's. Its tail is short and its wings are big, wide, and round-tipped; it soars well, although it does so less than the shoebill or storks. When it does so, it stretches its neck forward like a stork or

ibis The ibises () (collective plural ibis; classical plurals ibides and ibes) are a group of long-legged wading birds in the family Threskiornithidae, that inhabit wetlands, forests and plains. "Ibis" derives from the Latin and Ancient Greek word ...

, but when it flaps, it coils its neck back something like a heron. Its gait when walking is jerky and rapid, with its head and neck moving back and forth with each step. It may hold its wings out when running for extra stability.

Distribution and habitat

The hamerkop occurs in

south of the Sahara,

, and coastal south-west Arabia. It requires shallow water in which to forage, and is found in all wetland habitats, including rivers, streams, seasonal pools, estuaries, reservoirs, marshes, mangroves, irrigated land such as rice paddies, savannahs, and

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s. In Tanzania, it has also recently begun to feed on rocky shores. In Arabia, it is found in rocky

wadi Wadi ( ar, وَادِي, wādī), alternatively ''wād'' ( ar, وَاد), North African Arabic Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet (ephemeral) riverbed that contains water ...

s with running water and trees. Most are sedentary within their territories, which are held by pairs, but some migrate into suitable habitat during the

wet season The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...

only. The species is very tolerant of humans and readily feeds and breeds in villages and other human-created habitats.

Behaviour and ecology

The hamerkop is mostly active during the day, often resting at noon during the heat of the day. They can be somewhat crepuscular, being active around dusk, but are not nocturnal as has sometimes been reported.

Social behaviour and calls

The hamerkop is mostly silent when alone, but is fairly vocal when in pairs or in groups. The only call it usually makes when alone is a flight-call, a shrill “nyip” or “kek”. In groups, vocalisations include a range of calls including cackles and nasal rattles. One highly social call is the "yip-purr" call. This call is only made in a social context, when at least three birds, but up to 20 are gathered in a flock. Birds start by giving a number of "yip" calls, eventually giving way to purring notes. This call is made with the neck extended and sometimes accompanied by wing flapping, and becomes more vigorous when larger numbers of birds are present. Another common social behaviour is "false mounting", in which one bird stands on top of another and appears to mount it, but they do not copulate. This behaviour has been noted between both mated pairs and unmated birds, and even between members of the same sex and in reversed mountings, where females mount males. Because of this, the behaviour is thought to be social and not related to the pair bond. Dominant birds may signal to subordinates by opening their bills slightly and erecting their crests, but the species is not very aggressive in general towards others of its species. Birds in groups also engage in social

allopreening Preening is a found in birds that involves the use of the beak to position feathers, interlock feather that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, waterp ...

when in groups. One bird presents its face of back of the head to the other to be preened.

Food and feeding

A hamerkop (Scopus umbretta) about to eat a fish

This species normally feeds alone or in pairs, but also feeds in large flocks sometimes. It is a generalist, although amphibians and fish form the larger part of its diet. The diet also includes shrimp, insects, and rodents. The type of food they take seems to vary by location, with clawed frogs and tadpoles being important parts of the diet in East and Southern Africa and small fish being almost the only prey taken in Mali. Because it is willing to take a wide range of food items and also take very small prey, it is not resource-limited and only feeds for part of the day. The usual method of hunting is to walk in shallow water looking for prey. Prey is located differently depending on circumstances; if the water is clear, it may hunt by sight, but if the water is very muddy, it probes its open bill into water or mud and shuts it. It may shuffle one foot at a time on the bottom or suddenly open its wings to flush prey out of hiding. Prey caught in mud is shaken before swallowing to clean it, or if available, taken to clearer water to do so. The species also feeds while in flight. A bird flies slowly low over the water with legs dangling and head looking down, then dipping feet down and hovering momentarily when prey is sighted. The prey is then snatched with the bill and swallowed in flight. This method of hunting can be very successful, with one birds catching prey on 27 of 33 attempts during one 45-minute session. It is also opportunistic, and feeds on swarming

termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blatto ...

s when they conduct their nuptial flights, snatching as many as 47

alate Alate (Latin ''ālātus'', from ''āla'' (“wing”)) is an adjective and noun used in entomology and botany to refer to something that has wings or winglike structures. In entomology In entomology, "alate" usually refers to the winged form o ...

s (flying termites) in five minutes. This species has been recorded foraging for insects flushed by grazing cattle and buffalo, in a manner similar

cattle egret The cattle egret (''Bubulcus ibis'') is a cosmopolitan species of heron (family Ardeidae) found in the tropics, subtropics, and warm-temperate zones. It is the only member of the monotypic genus ''Bubulcus'', although some authorities regard ...

s, and has been observed fishing off the backs of hippopotamuses. It has also been recorded feeding in association with

banded mongoose The banded mongoose (''Mungos mungo'') is a mongoose species native from the Sahel to Southern Africa. It lives in savannas, open forests and grasslands and feeds primarily on beetles and millipedes. Mongooses use various types of dens for shelt ...

s; when a band of mongooses began hunting frogs in dried mud at the side of a pool of water a pair of hamerkops attended the feeding group, catching frogs that escaped the mongooses.

Breeding

The strangest aspect of hamerkop behaviour is the huge nest, sometimes more than across, and strong enough to support a man's weight. When possible, it is built in the fork of a tree, often over water, but if necessary, it is built 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 wide in the bottom leads through a tunnel up to long to a nesting chamber big enough for the parents and young. Nests have been recorded to take between 10 and 14 weeks to build, and one researcher estimated that they would require around 8,000 sticks or bunches of grass to complete. Nesting material may still be added by the pair after the nest has been completed and eggs have been laid. Much of the nesting material added after completion is not sticks, but an odd collection of random items including bones, hide, and human waste. Hammerkop with Nesting Material

Pairs of hamerkop are compulsive nest builders, constructing three to five nests per year whether they are breeding or not. Both members of the pair build the nest, and the building of nests may have a function in creating or maintaining the pair bond between them. Barn owls and eagle owls may force them out and take over the nests, but when the owls leave, the pair may reuse the nest. Owls may also use abandoned nests, as may snakes, small mammals such as genets, and various birds, and

weaver bird Ploceidae is a family of small passerine birds, many of which are called weavers, weaverbirds, weaver finches and bishops. These names come from the nests of intricately woven vegetation created by birds in this family. In most recent classifica ...

starlings Starlings are small to medium-sized passerine birds in the family Sturnidae. The Sturnidae are named for the genus '' Sturnus'', which in turn comes from the Latin word for starling, ''sturnus''. Many Asian species, particularly the larger ones, ...

, and

pigeon Columbidae () is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily ...

s may attach their nests to the outside. A few reports exist of hamerkops nesting close together, including in Uganda, where 639 nests were seen in an area of ; even if each pair had made seven nests, this would mean 80 pairs were nesting in that area. The species is not treated as

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

, as it does not habitually nest close together, but is not thought to be highly

territorial A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal. In international politics, a territory is usually either the total area from which a state may extract power resources or a ...

, either. Even where pairs have home ranges that are more spread out those home ranges overlap and are the boundaries are poorly defined. Breeding happens year-round in East Africa, and in the rest of its range, it peaks at different times, with a slight bias towards the dry season. Pairs engage in a breeding display, then copulate on the nest or on the ground nearby. The clutch consists of three to seven eggs which start chalky white, but soon become stained. The eggs measure on average, and weight around , but considerable variation is seen. Egg size varies by season, by the overall size of the clutch, and from bird to bird. Both sexes incubate the eggs, but the female seems to do the most of the work. Incubation takes around 30 days from the first egg being laid to hatching, eggs are laid with intervals of one to three days, and they hatch asynchronously. Both parents feed the young, often leaving them alone for long times. This habit, which is unusual for wading birds, may be made possible because of 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 first leave the nest around 44 to 50 days after hatching, but continue to use the nest for roosting at night until they are two months old.

Relationship with humans

Many legends exist about the hamerkop. In some regions, people state that other birds help it build its nest. The ǀXam informants of

Wilhelm Bleek Wilhelm Heinrich Immanuel Bleek (8 March 1827 – 17 August 1875) was a German linguist. His work included ''A Comparative Grammar of South African Languages'' and his great project jointly executed with Lucy Lloyd: The Bleek and Lloyd Archive o ...

said that when a hamerkop flew and called over their camp, they knew that someone close to them had died. It is known in some cultures as the lightning bird, and the

Kalahari Bushmen The San peoples (also Saan), or Bushmen, are members of various Khoe, Tuu, or Kxʼa-speaking indigenous hunter-gatherer cultures that are the first cultures of Southern Africa, and whose territories span Botswana, Namibia, Angola, Zambia, ...

believe or believed that being hit by lightning resulted from trying to rob a hamerkop's nest. They also believe that the

inimical Hostility is seen as form of emotionally charged aggressive behavior. In everyday speech it is more commonly used as a synonym for anger and aggression. It appears in several psychological theories. For instance it is a facet of neuroticism ...

god Khauna would not like anyone to kill a hamerkop. According to an old Malagasy belief, anyone who destroys its nest will get

leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...

, and a Malagasy poem calls it an "evil bird". Such beliefs have given the bird some protection. A south African name Njaka meaning "rain doctor" is derived from its habit of calling loudly prior to rain.

Scopus Scopus is Elsevier's abstract and citation database launched in 2004. Scopus covers nearly 36,377 titles (22,794 active titles and 13,583 inactive titles) from approximately 11,678 publishers, of which 34,346 are peer-reviewed journals in top-l ...

, a database of abstracts and citations for scholarly journal articles, received its name in honour of this bird, as did the journal of the East African Natural History Society, ''

''.

References

External links

Hamerkop videos, photos and sounds
on the Internet Bird Collection
Hamerkop
- '' The Atlas of Southern African Birds'' {{Taxonbar, from=Q652151 Birds of Sub-Saharan Africa Pelecaniformes Birds described in 1789 Taxa named by Johann Friedrich Gmelin Birds of East Africa