The herons are long-legged freshwater and coastal birds in the family Ardeidae, with 64 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera Botaurus and Ixobrychus are referred to as bitterns, and, together with the zigzag heron, or zigzag bittern, in the monotypic genus Zebrilus, form a monophyletic group within the Ardeidae. Egrets are not a biologically distinct group from the herons, and tend to be named differently because they are mainly white or have decorative plumes in breeding plumage. Herons, by evolutionary adaptation, have long beaks.
The classification of the individual heron/egret species is fraught with difficulty, and no clear consensus exists about the correct placement of many species into either of the two major genera, Ardea and Egretta. Similarly, the relationships of the genera in the family are not completely resolved. However, one species formerly considered to constitute a separate monotypic family, the Cochlearidae or the boat-billed heron, is now regarded as a member of the Ardeidae.
Although herons resemble birds in some other families, such as the storks, ibises, spoonbills, and cranes, they differ from these in flying with their necks retracted, not outstretched. They are also one of the bird groups that have powder down. Some members of this group nest colonially in trees, while others, notably the bitterns, use reed beds.
|Great blue heron (Ardea herodias)|
About 21 extant, see text
|Global distribution of herons|
The herons are medium- to large-sized birds with long legs and necks. They exhibit very little sexual dimorphism in size. The smallest species is usually considered the dwarf bittern, which measures 25–30 cm (9.8–11.8 in) in length, although all the species in the genus Ixobrychus are small and many broadly overlap in size. The largest species of heron is the goliath heron, which stands up to 152 cm (60 in) tall. The necks are able to kink in an S-shape, due to the modified shape of the cervical vertebrae, of which they have 20–21. The neck is able to retract and extend, and is retracted during flight, unlike most other long-necked birds. The neck is longer in the day herons than the night herons and bitterns. The legs are long and strong and in almost every species are unfeathered from the lower part of the tibia (the exception is the zigzag heron). In flight, the legs and feet are held backward. The feet of herons have long, thin toes, with three forward-pointing ones and one pointing backward.
The bill is generally long and harpoon-like. It can vary from extremely fine, as in the agami heron, to thick as in the grey heron. The most atypical bill is owned by the boat-billed heron, which has a broad, thick bill. The bill, as well as other bare parts of the body, is usually yellow, black, or brown in colour, although this can vary during the breeding season. The wings are broad and long, exhibiting 10 or 11 primary feathers (the boat-billed heron has only nine), 15–20 secondaries. and 12 rectrices (10 in the bitterns). The feathers of the herons are soft and the plumage is usually blue, black, brown, grey, or white, and can often be strikingly complex. Amongst the day herons, little sexual dimorphism in plumage is seen (except in the pond-herons); differences between the sexes are the rule for the night herons and smaller bitterns. Many species also have different colour morphs. In the Pacific reef heron, both dark and light colour morphs exist, and the percentage of each morph varies geographically. White morphs only occur in areas with coral beaches.
The herons are a widespread family with a cosmopolitan distribution. They exist on all continents except Antarctica, and are present in most habitats except the coldest extremes of the Arctic, extremely high mountains, and the driest deserts. Almost all species are associated with water; they are essentially nonswimming waterbirds that feed on the margins of lakes, rivers, swamps, ponds, and the sea. They are predominantly found in lowland areas, although some species live in alpine areas, and the majority of species occurs in the tropics.
The herons are a highly mobile family, with most species being at least partially migratory. Some species are partially migratory, for example the grey heron, which is mostly sedentary in Britain, but mostly migratory in Scandinavia. Birds are particularly inclined to disperse widely after breeding, but before the annual migration, where the species is colonial, searching out new feeding areas and reducing the pressures on feeding grounds near the colony. The migration typically occurs at night, usually as individuals or in small groups.
The herons and bitterns are carnivorous. The members of this family are mostly associated with wetlands and water, and feed on a variety of live aquatic prey. Their diet includes a wide variety of aquatic animals, including fish, reptiles, amphibians, crustaceans, molluscs, and aquatic insects. Individual species may be generalists or specialise in certain prey types, such as the yellow-crowned night heron, which specialises in crustaceans, particularly crabs. Many species also opportunistically take larger prey, including birds and bird eggs, rodents, and more rarely carrion. Even more rarely, herons eating acorns, peas, and grains have been reported, but most vegetable matter consumed is accidental.
The most common hunting technique is for the bird to sit motionless on the edge of or standing in shallow water and to wait until prey comes within range. Birds may either do this from an upright posture, giving them a wider field of view for seeing prey, or from a crouched position, which is more cryptic and means the bill is closer to the prey when it is located. Having seen prey, the head is moved from side to side, so that the heron can calculate the position of the prey in the water and compensate for refraction, and then the bill is used to spear the prey.
In addition to sitting and waiting, herons may feed more actively. They may walk slowly, around or less than 60 paces a minute, snatching prey when it is observed. Other active feeding behaviours include foot stirring and probing, where the feet are used to flush out hidden prey. The wings may be used to frighten prey (or possibly attract it to shade) or to reduce glare; the most extreme example of this is exhibited by the black heron, which forms a full canopy with its wings over its body.
Some species of heron, such as the little egret and grey heron, have been documented using bait to lure prey to within striking distance. Herons may use items already in place, or actively add items to the water to attract fish such as the banded killifish. Items used may be man-made, such as bread; alternatively, striated herons in the Amazon have been watched repeatedly dropping seeds, insects, flowers, and leaves into the water to catch fish.
Three species, the black-headed heron, whistling heron, and especially the cattle egret, are less tied to watery environments and may feed far away from water. Cattle egrets improve their foraging success by following large grazing animals, catching insects flushed by their movement. One study found that the success rate of prey capture increased 3.6 times over solitary foraging.
While the family exhibits a range of breeding strategies, overall, the herons are monogamous and mostly colonial. Most day herons and night herons are colonial, or partly colonial depending on circumstances, whereas the bitterns and tiger herons are mostly solitary nesters. Colonies may contain several species, as well as other species of waterbirds. In a study of little egrets and cattle egrets in India, the majority of the colonies surveyed contained both species. Nesting is seasonal in temperate species; in tropical species, it may be seasonal (often coinciding with the rainy season) or year-round. Even in year-round breeders, nesting intensity varies throughout the year. Tropical herons typically have only one breeding season per year, unlike some other tropical birds which may raise up to three broods a year.
Courtship usually takes part on the nest. Males arrive first and begin the building of the nest, where they display to attract females. During courtship, the male employs a stretch display and uses erectile neck feathers; the neck area may swell. The female risks an aggressive attack if she approaches too soon and may have to wait up to four days. In colonial species, displays involve visual cues, which can include adopting postures or ritual displays, whereas in solitary species, auditory cues, such as the deep booming of the bitterns, are important. The exception to this is the boat-billed heron, which pairs up away from the nesting site. Having paired, they continue to build the nest in almost all species, although in the little bittern and least bittern, only the male works on the nest.
The nests of herons are usually found near or above water. They are typically placed in vegetation, although the nests of a few species have been found on the ground where suitable trees of shrubs are unavailable. Trees are used by many species, and here they may be placed high up from the ground, whereas species living in reed beds may nest very close to the ground.
Generally, herons lay between three and seven eggs. Larger clutches are reported in the smaller bitterns and more rarely some of the larger day herons, and single-egg clutches are reported for some of the tiger herons. Clutch size varies by latitude within species, with individuals in temperate climates laying more eggs than tropical ones. On the whole, the eggs are glossy blue or white, with the exception being the large bitterns, which lay olive-brown eggs.
The word heron first appeared in the English language around 1300, originating from Old French hairon, eron (12th century), earlier hairo (11th century), from Frankish haigiro or from Proto-Germanic *haigrô, *hraigrô.
Herons are also known as shitepokes /ˈʃaɪtpoʊk/, or euphemistically as shikepokes or shypokes. Webster's Dictionary suggests that herons were given this name because of their habit of defecating when flushed.
The 1971 Compact Edition of the Oxford English Dictionary describes the use of shitepoke for the small green heron of North America (Butorides virescens) as originating in the United States, citing a published example from 1853. The OED also observes that shiterow or shederow are terms used for herons, and also applied as derogatory terms meaning a thin, weakly person. This name for a heron is found in a list of gamebirds in a royal decree of James VI (1566–1625) of Scotland. The OED speculates that shiterow is a corruption of shiteheron.
Another former name was heronshaw or hernshaw, derived from Old French heronçeau. Corrupted to handsaw, this name appears in Shakespeare's Hamlet. A possible further corruption took place in the Norfolk Broads, where the heron is often referred to as a harnser.
Analyses of the skeleton, mainly the skull, suggested that the Ardeidae could be split into a diurnal and a crepuscular/nocturnal group which included the bitterns. From DNA studies and skeletal analyses focusing more on bones of body and limbs, this grouping has been revealed as incorrect. Rather, the similarities in skull morphology reflect convergent evolution to cope with the different challenges of daytime and nighttime feeding. Today, it is believed that three major groups can be distinguished, which are (from the most primitive to the most advanced):
The night herons could warrant separation as subfamily Nycticoracinae, as it was traditionally done. However, the position of some genera (e.g. Butorides or Syrigma) is unclear at the moment, and molecular studies have until now suffered from a small number of studied taxa. Especially, the relationships among the subfamily Ardeinae are very badly resolved. The arrangement presented here should be considered provisional.
A 2008 study suggests that this family belongs to the Pelecaniformes. In response to these findings, the International Ornithological Congress recently reclassified Ardeidae and their sister taxa Threskiornithidae under the order Pelecaniformes instead of the previous order of Ciconiiformes.
Other prehistoric and fossil species are included in the respective genus accounts. In addition, Proherodius is a disputed fossil which was variously considered a heron or one of the extinct long-legged waterfowl, the Presbyornithidae. It is only known from a sternum; a tarsometatarsus assigned to it actually belongs to the paleognath Lithornis vulturinus.
The black-crowned night heron (Nycticorax nycticorax), or black-capped night heron, commonly shortened to just night heron in Eurasia, is a medium-sized heron found throughout a large part of the world, except in the coldest regions and Australasia (where it is replaced by the closely related rufous night heron, with which it has hybridized in the area of contact).Chérencé-le-Héron
Chérencé-le-Héron is a commune in the Manche department in Normandy in north-western France.Clan Heron
The Clan Heron was a lowland Scottish clan. One branch of the clan were border reivers who made a living by rustling cattle along the Anglo-Scottish border. Another branch were a landed family with their seat in Kirkcudbright.De Havilland Heron
The de Havilland DH.114 Heron was a small propeller-driven British airliner that first flew on 10 May 1950. It was a development of the twin-engine de Havilland Dove, with a stretched fuselage and two more engines. It was designed as a rugged, conventional low-wing monoplane with tricycle undercarriage that could be used on regional and commuter routes. 150 were built, also exported to about 30 countries. Herons later formed the basis for various conversions, such as the Riley Turbo Skyliner and the Saunders ST-27 and ST-28.Gil Scott-Heron
Gilbert Scott-Heron (April 1, 1949 – May 27, 2011) was an American soul and jazz poet, musician, and author, known primarily for his work as a spoken-word performer in the 1970s and 1980s. His collaborative efforts with musician Brian Jackson featured a musical fusion of jazz, blues, and soul, as well as lyrical content concerning social and political issues of the time, delivered in both rapping and melismatic vocal styles by Scott-Heron. His own term for himself was "bluesologist", which he defined as "a scientist who is concerned with the origin of the blues".His music, most notably on the albums Pieces of a Man and Winter in America in the early 1970s, influenced and foreshadowed later African-American music genres such as hip hop and neo soul. Scott-Heron is considered by many to be the first rapper/MC ever. His recording work received much critical acclaim, especially one of his best-known compositions, "The Revolution Will Not Be Televised". AllMusic's John Bush called him "one of the most important progenitors of rap music," stating that "his aggressive, no-nonsense street poetry inspired a legion of intelligent rappers while his engaging songwriting skills placed him square in the R&B charts later in his career."Scott-Heron remained active until his death, and in 2010 released his first new album in 16 years, entitled I'm New Here. A memoir he had been working on for years up to the time of his death, The Last Holiday, was published posthumously in January 2012. Scott-Heron received a posthumous Grammy Lifetime Achievement Award in 2012. He also is included in the exhibits at the National Museum of African American History and Culture (NMAAHC) that officially opened on September 24, 2016, on the National Mall, and in an NMAAHC publication, Dream a World Anew.Great blue heron
The great blue heron (Ardea herodias) is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North America and Central America, as well as the Caribbean and the Galápagos Islands. It is a rare vagrant to coastal Spain, the Azores, and areas of far southern Europe. An all-white population found only in south Florida and the Florida Keys is known as the great white heron. Debate exists about whether it is a white color morph of the great blue heron, a subspecies of it, or an entirely separate species.Green heron
The green heron (Butorides virescens) is a small heron of North and Central America. Butorides is from Middle English butor "bittern" and Ancient Greek -oides, "resembling", and virescens is Latin for "greenish".It was long considered conspecific with its sister species the striated heron (Butorides striata), and together they were called "green-backed heron". Birds of the nominate subspecies (no matter which taxonomic arrangement is preferred) are extremely rare vagrants to western Europe—for example, a sighting in Pembrokeshire in 2018 was only the second recorded sighting in Wales; individuals from the Pacific coast of North America may similarly stray as far as Hawaii.Grey heron
The grey heron (Ardea cinerea) is a long-legged predatory wading bird of the heron family, Ardeidae, native throughout temperate Europe and Asia and also parts of Africa. It is resident in much of its range, but some populations from the more northern parts migrate southwards in autumn. A bird of wetland areas, it can be seen around lakes, rivers, ponds, marshes and on the sea coast. It feeds mostly on aquatic creatures which it catches after standing stationary beside or in the water or stalking its prey through the shallows.
Standing up to 1 m tall, adults weigh from 1 to 2 kg (2.2 to 4.4 lb). They have a white head and neck with a broad black stripe that extends from the eye to the black crest. The body and wings are grey above and the underparts are greyish-white, with some black on the flanks. The long, sharply pointed beak is pinkish-yellow and the legs are brown.
The birds breed colonially in spring in "heronries", usually building their nests high in trees. A clutch of usually three to five bluish-green eggs is laid. Both birds incubate the eggs for around 25 days, and then both feed the chicks, which fledge when 7-8 weeks old. Many juveniles do not survive their first winter, but if they do, they can expect to live for about 5 years.
In Ancient Egypt, the deity Bennu was depicted as a heron in New Kingdom artwork.
In Ancient Rome, the heron was a bird of divination. Roast heron was once a specially prized dish; when George Neville became Archbishop of York in 1465, 400 herons were served to the guests.Hero of Alexandria
Hero of Alexandria (; Greek: Ἥρων ὁ Ἀλεξανδρεύς, Heron ho Alexandreus; also known as Heron of Alexandria ; c. 10 AD – c. 70 AD) was a mathematician and engineer who was active in his native city of Alexandria, Roman Egypt. He is considered the greatest experimenter of antiquity and his work is representative of the Hellenistic scientific tradition.Hero published a well-recognized description of a steam-powered device called an aeolipile (sometimes called a "Hero engine"). Among his most famous inventions was a windwheel, constituting the earliest instance of wind harnessing on land. He is said to have been a follower of the atomists. Some of his ideas were derived from the works of Ctesibius.
Much of Hero's original writings and designs have been lost, but some of his works were preserved - mostly in manuscripts from the Eastern Roman Empire, and a smaller part in Latin or Arabic translations.Heron's formula
In geometry, Heron's formula (sometimes called Hero's formula), named after Hero of Alexandria, gives the area of a triangle when the length of all three sides are known. Unlike other formulas, there is no need to calculate other distances in the triangle first.Heron Tower
110 Bishopsgate (formerly Heron Tower) is a commercial skyscraper in London. It stands 230 metres (755 ft) tall including its 28-metre (92 ft) mast making it the tallest building in the City of London financial district and the third tallest in Greater London and the United Kingdom, after the Shard in Southwark and One Canada Square at Canary Wharf. 110 Bishopsgate is located on Bishopsgate and is bordered by Camomile Street, Outwich Street and Houndsditch.
Construction of the building started in 2007 and was completed in 2011. It is owned by Heron International and is still popularly known as Heron Tower, though following a naming dispute in 2014 involving the tenant Salesforce.com the City of London ruled in favour of the property being officially named 110 Bishopsgate. The tower initially struggled to attract tenants in the depths of the Great Recession, but is now fully let.IAI Heron
The IAI Heron (Machatz-1) is a medium-altitude long-endurance unmanned aerial vehicle (UAV) developed by the Malat
(UAV) division of Israel Aerospace Industries. It is capable of Medium Altitude Long Endurance (MALE) operations of up to 52 hours' duration at up to 10.5 km (35,000 ft). It has demonstrated 52 hours of continuous flight, but the effective operational maximal flight duration is less, according to payload and flight profile. An advanced version, the Heron TP, is also known as the IAI Eitan.
On 11 September 2005, it was announced that the Israel Defense Forces purchased US$50 million worth of Heron systems.Le Héron
Le Héron is a commune in the Seine-Maritime department in the Normandy region in north-western France.Little blue heron
The little blue heron (Egretta caerulea) is a small heron. It breeds in the Gulf states of the US, through Central America and the Caribbean south to Peru and Uruguay. It is a resident breeder in most of its range, but some northern breeders migrate to the southeastern US or beyond in winter. There is post-breeding dispersal to well north of the nesting range, as far as the Canada–US border.Purple heron
The purple heron (Ardea purpurea) is a wide-ranging species of wading bird in the heron family, Ardeidae. The scientific name comes from Latin ardea "heron", and purpureus, "coloured purple". It breeds in Africa, central and southern Europe, and southern and eastern Asia. The Western Palearctic populations migrate between breeding and wintering habitats whereas the African and tropical-Asian populations are primarily sedentary, except for occasional dispersive movements.
It is similar in appearance to the more common grey heron but is slightly smaller, more slender and has darker plumage. It is also a more evasive bird, favouring densely vegetated habitats near water, particularly reed beds. It hunts for a range of prey including fish, rodents, frogs and insects, either stalking them or standing waiting in ambush.
Purple herons are colonial breeders and build a bulky nest out of dead reeds or sticks close to the water' edge among reeds or in dense vegetation. About five bluish-green eggs are laid and are incubated by both birds. The young hatch about four weeks later and fledge six weeks after that. The International Union for Conservation of Nature notes that the global population trend is downwards, largely because of the drainage of wetlands, but assesses the purple heron's conservation status as being of "least concern".Snowy egret
The snowy egret (Egretta thula) is a small white heron. The genus name comes from the Provençal French for the little egret aigrette, a diminutive of aigron, "heron". The species name thula is the Araucano for the Black-necked Swan, applied to this species in error by Chilean naturalist Juan Ignacio Molina in 1782.The snowy egret is the American counterpart to the very similar Old World little egret, which has established a foothold in the Bahamas. At one time, the beautiful plumes of the snowy egret were in great demand by market hunters as decorations for women's hats. This reduced the population of the species to dangerously low levels. Now protected in the United States by law, under the Migratory Bird Treaty Act, this bird's population has rebounded.Striated heron
The striated heron (Butorides striata) also known as mangrove heron, little heron or green-backed heron, is a small heron, about 44 cm tall. Striated herons are mostly non-migratory and noted for some interesting behavioral traits. Their breeding habitat is small wetlands in the Old World tropics from west Africa to Japan and Australia, and in South America. Vagrants have been recorded on oceanic islands, such as Chuuk and Yap in the Federated States of Micronesia, the Marianas and Palau; the bird recorded on Yap on February 25, 1991, was from a continental Asian rather than from a Melanesian population, while the origin of the bird seen on Palau on May 3, 2005 was not clear.This bird was long considered to be conspecific with the closely related North American species, the green heron, which is now usually separated as B. virescens, as well as the lava heron of the Galápagos Islands (now B. sundevalli, but often included in B. striata, e.g. by BirdLife International); collectively they were called "green-backed herons".
The bird can also be found in Bolivia around the town of Riberalta in the Beni Department and specifically in the Aquicuana Reserve.Tricolored heron
The tricolored heron (Egretta tricolor), formerly known as the Louisiana heron, is a small species of heron that is native to coastal parts of the Americas. In the Atlantic region in ranges from northeastern United States, south along the coast, through the Mexican Gulf and the Caribbean, to northern South America as far south as Brazil. In the Pacific region it ranges from Peru to California, but it is only a non-breeding visitor to the far north.
Tricolored herons breed in swamps and other coastal habitats. It nests in colonies, often with other herons, usually on platforms of sticks in trees or shrubs. In each clutch, 3–7 eggs are typically laid.
This species measures from 56 to 76 cm (22 to 30 in) long and has a wingspan of 96 cm (38 in). The slightly larger male heron weighs 415 g (14.6 oz) on average, while the female averages 334 g (11.8 oz). It is a medium-large, long-legged, long-necked heron with a long pointed yellowish or greyish bill with a black tip. The legs and feet are dark.
Adults have a blue-grey head, neck, back and upperwings, with a white line along the neck. The belly is white. In breeding plumage, they have long blue filamentous plumes on the head and neck, and buff ones on the back.
The tricolored heron stalks its prey in shallow or deeper water, often running as it does so. It eats fish, crustaceans, reptiles, and insects.Yellow-crowned night heron
The yellow-crowned night heron (Nyctanassa violacea), is one of two species of night herons found in the Americas, the other one being the black-crowned night heron. It is known as the Bihoreau Violacé in French and the Pedrete Corona Clara in Spanish.