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Heron

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Herons
Temporal range: EarlyOligocene–Holocene32–0Ma[1]
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Suborder: Ardei
Family: Ardeidae
Leach,1820
Type genus
Ardea
Genera

18 extant, seetext

Global distribution of herons
Synonyms

Cochlearidae

Heronsare long-legged, long-necked, freshwater and coastalbirdsin the familyArdeidae,with 72 recognisedspecies,some of which are referred to asegretsorbitternsrather than herons. Members of the generaBotaurusandIxobrychusare referred to as bitterns, and, together with thezigzag heron,or zigzag bittern, in the monotypic genusZebrilus,form amonophyleticgroup within the Ardeidae.Egretsdo not form a biologically distinct group from 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,ArdeaandEgretta.Similarly, the relationships of thegenerain the family are not completely resolved. However, one species formerly considered to constitute a separatemonotypicfamily, the Cochlearidae or theboat-billed heron,is now regarded as a member of the Ardeidae.

Although herons resemble birds in some other families, such as thestorks,ibises,spoonbills,andcranes,they differ from these in flying with their necks retracted, not outstretched. They are also one of the bird groups that havepowder down.Some members of this group nestcoloniallyin trees, while others, notably the bitterns, usereed beds.A group of herons has been called a "siege".[2]

Name[edit]

The wordheronfirst appeared in the English language around 1300, originating from Old Frenchhairon, eron(12th century), earlierhairo(11th century), from Frankishhaigiroor from Proto-Germanic*haigrô,*hraigrô.[3]

Herons are also known asshitepokes/ˈʃaɪtpoʊk/,or euphemistically asshikepokesorshypokes.Webster's Dictionarysuggests that herons were given this name because of their habit of defecating when flushed.[4]

The 1971Compact Edition of the Oxford English Dictionarydescribes the use ofshitepokefor the small green heron of North America (Butorides virescens) as originating in the United States, citing a published example from 1853. TheOEDalso observes thatshiteroworshederoware terms used for herons, and also applied as derogatory terms meaning athin, weakly person.This name for a heron is found in a list of game birds in a royal decree ofJames VI(1566–1625) ofScotland.TheOEDspeculates thatshiterowis a corruption ofshiteheron.[5]

Another former name washeronshaworhernshaw,derived from Old Frenchheronçeau.Corrupted tohandsaw,this name appears inShakespeare'sHamlet.[6]A possible further corruption took place in the Norfolk Broads, where the heron is often referred to as aharnser.

Description[edit]

A beige heron with yellow legs and bill stands hunched on a wire mesh above water, its neck folded tightly to its body and hidden among feathers.
Yellow bitternwith its neck fully retracted.

The herons are medium- to large-sized birds with long legs and necks. They exhibit very littlesexual dimorphismin size. The smallest species is usually considered thedwarf bittern,which measures 25–30 cm (10–12 in) in length, although all the species in the genusIxobrychusare small and many broadly overlap in size. The largest species of heron is thegoliath heron,which stands up to 152 cm (60 in) tall. All herons can retract their necks by folding them into a tight S-shape, due to the modified shape of the cervical vertebrae, of which they have 20 or 21; the neck 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 thetibia(the exception is thezigzag heron). In flight, the legs and feet are generally held in a horizontal position, pointing backwards. Toes are long and thin, with three pointing forwards and one backwards.[7]

two herons, one with white plumage and one with slate grey, on a rock in the surf of the ocean
ThePacific reef heronhas twocolour morphs,the light and the dark.

Thebillis generally long and harpoon-like. It can vary from extremely narrow, as in theagami heron,to wider as in thegrey heron.The most atypical heron bill is owned by theboat-billed heron,which has a broad, thick bill. Herons' bills and other bare parts of the body are usually yellow, black, or brown in colour, although this can vary during the breeding season. The wings are broad and long, exhibiting 10 or 11primary 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 theplumageis 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); however, for the night herons and smaller bitterns, plumage differences between the sexes are the rule. Many species also have differentcolour morphs.[7]In thePacific reef heron,both dark and light colour morphs exist, and the percentage of each morph varies geographically; its white morphs only occur in areas with coral beaches.[8]

Distribution and habitat[edit]

Lava heron, grey with a long bill and red feet and with small fish in bill amongst grey rocks
Lava heronsare endemic to theGalápagos Islands,where they feed on fish and crabs in the intertidal and mangrove areas.

The herons are a widespread family with acosmopolitan distribution.They exist on all continents exceptAntarcticaand 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 non-swimming 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 occur in the tropics.[7]

The herons are a highly mobile family, with most species being at least partiallymigratory;for example, thegrey heronis 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.[7]

Behaviour and ecology[edit]

Diet[edit]

A white heron with grey legs and a yellow/orange bill standing in green grasses throwing a lizard with its bill
Agreat egretmanipulating its prey, a lizard, before swallowing

The herons and bitterns arecarnivorous.The members of this family are mostly associated withwetlandsand water and feed on a variety of liveaquaticprey. Their diet includes a wide variety of aquatic animals, including fish, reptiles,amphibians,crustaceans,molluscs,and aquatic insects. Individual species may be generalists or specialize in certain prey types, such as theyellow-crowned night heron,which specializes in crustaceans, particularlycrabs.[9]Many species also opportunistically take larger prey, including birds and bird eggs, rodents, and more rarelycarrion.Even more rarely, herons eating acorns, peas, and grains have been reported, but most vegetable matter consumed is accidental.[7]

Four black herons standing in low water with vegetation holding their wings over their bodies forming what looks like umbrellas
Black heronsholding wings out to form an umbrella-like canopy under which to hunt

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 forrefraction,and then the bill is used to spear the prey.[7]

Tricoloured heronfishing, using wings to eliminate reflection from the water, which improves its ability to sight 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.[10]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 theblack heron,which forms a full canopy with its wings over its body.[11]

Some species of heron, such as thelittle egretand 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 thebanded killifish.Items used may be man-made, such as bread;[12]alternatively,striated heronsin theAmazonhave been watched repeatedly dropping seeds, insects, flowers, and leaves into the water to catch fish.[13]

Three species, theblack-headed heron,whistling heron,and especially thecattle 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.[14]

Breeding[edit]

A brown heron with brown, back and beige coloured streaks stands in similarly coloured dead grasses, its head pointed upwards
The larger bitterns, like thisAmerican bittern,are solitary breeders. To advertise for mates, males use loud, characteristic calls, referred to as booming.

While the family exhibits a range of breeding strategies, overall, the herons aremonogamousand mostlycolonial.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.[15]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.[7]

Courtship usually takes part on thenest.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.[16]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 thelittle bitternandleast bittern,only the male works on the nest.[7]

Someornithologistshave reported observing female herons attaching themselves toimpotentmates, then seeking sexual gratification elsewhere.[7]

The nests of herons are usually found near or above water. Although the nests of a few species have been found on the ground where suitable trees or shrubs are unavailable, they are typically placed in vegetation.[7][15]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.[7]Though the majority of nesting of herons is seen in or immediately around water, colonies commonly occur in several cities when human persecution is absent.[17]

Generally, herons lay betweenthree 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.[7]

Taxonomy and systematics[edit]

See also:List of heron species

Analyses of skeletons, mainlyskulls,suggested that the Ardeidae could be split into adiurnaland acrepuscular/nocturnalgroup which included the bitterns. FromDNAstudies, and from skeletal analyses that focussed more on bones of the body and limbs, that two-group division has been revealed to be incorrect.[18]Rather, the similarities in skullmorphologyamong certain herons reflectconvergent evolutionto cope with the different challenges of daytime and nighttime feeding. Today, it is believed that three major groups can be distinguished,[19][20]which are:

  • tiger herons and the boatbill
  • bitterns
  • day herons and egrets, and night herons

The night herons may still warrant separation from the day herons and egrets (as subfamily Nycticoracinae, as it was traditionally done). However, the position of some genera (e.g.ButoridesorSyrigma) is unclear at the moment, and molecular studies have so far suffered from studying only a small number of taxa. Especially among the subfamily Ardeinae, the relationships are very inadequately resolved. The arrangement presented here should be considered provisional.

A 2008 study suggests that this family belongs to thePelecaniformes.[21]In response to these findings, theInternational Ornithological Congressreclassified Ardeidae and their sister taxaThreskiornithidaeunder the order Pelecaniformes instead of the previous order ofCiconiiformes.[22]

The cladogram shown below is based on amolecular phylogeneticstudy of the Ardeidae by Jack Hruska and collaborators published in 2023.[23]For several species these results conflict with the taxonomy published online in July 2023 byFrank Gill,Pamela Rasmussenand David Donsker on behalf of theInternational Ornithological Committee(IOC).[22]Theleast bittern(Ixobrychus exilis) and thestripe-backed bittern(Ixobrychus involucris) were nested with members of the genusBotaurus.Hruska and collaborators resurrected the genusCalherodiusPeters,1931 to contain two night herons (thewhite-backed night heronand thewhite-eared night heron) that were previously placed inGorsachius.Thewestern cattle egret(Bubulcus ibis) was embedded in the genusArdea.Theeastern cattle egret(Bubulcus coromandus) was not sampled. The placement of theforest bittern(Zonerodius heliosylus) was ambiguous, but the results suggest that it is probably closely related to members of the genusArdeolarather than to the subfamilyTigriornithinae.[23]

Ardeidae
Tigriornithinae

Tigriornis– white-crested tiger heron

Tigrisoma– tiger herons (3 species)

Cochleariinae

Cochlearius– boat-billed heron

Agamiinae

Agamia– agami heron

Botaurinae

Zebrilus– zigzag heron

Botaurus– bitterns (6 species)

Ixobrychus– bitterns (8 species of which 1 extinct)

Ardeinae

Gorsachius– night herons (4 species)

Calherodius– night herons (2 species)

Pilherodius– capped heron

Syrigma– whistling heron

Egretta– herons and egrets (13 species)

Nyctanassa– night herons (2 species of which 1 extinct)

Nycticorax– night herons (6 species of which 4 extinct)

Butorides– herons (3 species)

Ardeola– pond herons (6 species)

Ardea– herons and egrets (14 species, including cattle egrets)

As of July 2023 the IOC lists 72 heron species, divided into 18 genera.[22]

  • SubfamilyTigriornithinae
  • Subfamily Cochleariinae
  • Subfamily Agamiinae
  • SubfamilyBotaurinae
    • GenusZebrilus– zigzag heron
    • GenusIxobrychus– small bitterns (eight living species, one recentlyextinct)
    • GenusBotaurus– large bitterns (four species)
    • GenusPikaihao– Saint Bathan's bittern (fossil,Early Miocene of Otago, New Zealand)
  • SubfamilyArdeinae
    • GenusZeltornis(fossil,Early Miocene of Djebel Zelten, Libya)
    • GenusNycticorax– typical night herons (two living species, four recently extinct; sometimes includesNyctanassa)
    • GenusNyctanassa– American night herons (one living species, one recently extinct)
    • GenusGorsachius– Asian and African night herons (four species)
    • GenusButorides– green-backed herons (three species; sometimes included inArdea)
    • GenusPilherodius– capped heron
    • GenusZonerodius– forest bittern
    • GenusArdeola– pond herons (six species)
    • GenusBubulcus– cattle egrets (one or two species, sometimes included inArdea)
    • GenusProardea(fossil)
    • GenusArdea– typical herons (11–17 species)
    • GenusSyrigma– whistling heron
    • GenusEgretta– typical egrets (7–13 species)
    • Genus undetermined
      • Easter Island heron, Ardeidaegen. et sp. indet.(prehistoric)
Fossil herons of unresolved affiliations
  • "Anas" basaltica(Late Oligocene of Varnsdorf, Czech Republic)
  • Ardeagradis
  • Proardeola– possibly same asProardea
  • Matuku(Early Miocene of Otago, New Zealand)

Other prehistoric and fossil species are included in the respective genus accounts. In addition,Proherodiusis a disputed fossil which was variously considered a heron or one of the extinct long-leggedwaterfowl,thePresbyornithidae.It is only known from asternum;atarsometatarsusthat had been assigned to it actually belongs to thepaleognathLithornisvulturinus.

Symbolic meaning in mysticism[edit]

In Buddhism, a heron symbolizes purity, transformation and the wisdom of the Buddha. In addition, as a bird that transcends elements – on the earth, in the water and in the air – the heron symbolizes the expansion of awareness and the ubiquity of consciousness.

In Native American culture, this bird symbolizes renewal, rejuvenation and rebirth – an ever present reminder that we are all a part of a larger cycle of life and death.

References[edit]

  1. ^Mayr, G.et al.(2018) A fossil heron from the early Oligocene of Belgium – the earliest temporally well-constrained record of the Ardeidae.Ibis,161(1) DOI:10.1111/ibi.12600
  2. ^Lipton, James (1991).An Exaltation of Larks.Viking.ISBN978-0-670-30044-0.
  3. ^Harper, Douglas."heron".Online Etymology Dictionary.
  4. ^"Shitepoke" and "Shikepoke" entries,Webster's Third International Dictionary of the English Language Unabridged,Philip Babcock Gove,Editor in Chief,G. and C. Mirriam Company,1971ISBN0-87779-001-9
  5. ^"Shitepoke" and "shiterow" entries,Compact Edition of the Oxford English Dictionary,Oxford University Press,1971,Library of Congress Catalogue Card Number76-188038
  6. ^Armitage, Simon(2009).The Poetry of Birds.Penguin. p. 404.ISBN978-0141941868.
  7. ^abcdefghijklMartínez-Vilalta, Albert; Motis, Anna (1992). "Family Ardeidae (herons)". In del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.).Handbook of the Birds of the World.Volume 1: Ostriches to Ducks.Barcelona: Lynx Edicions. pp.376–403.ISBN978-84-87334-10-8.
  8. ^Itoh, Singi (1991)."Geographical Variation of the Plumage Polymorphism in the eastern reef heron (Egretta sacra) "(PDF).The Condor.93(2): 383–389.doi:10.2307/1368954.JSTOR1368954.
  9. ^Watts, Bryan (1988)."Foraging Implications of Food Usage Patterns in yellow-browned night-herons"(PDF).The Condor.90(4): 860–865.doi:10.2307/1368843.JSTOR1368843.
  10. ^Meyerriecks, Andrew (1966)."Additional Observations on" Foot-Stirring "Feeding Behavior in herons"(PDF).The Auk.83(3): 471–472.doi:10.2307/4083060.JSTOR4083060.
  11. ^Delacour, J (1946)."Under-Wing Fishing of the black heron,Melanophoyx ardesiaca"(PDF).The Auk.63(3): 441–442.doi:10.2307/4080141.JSTOR4080141.
  12. ^Post, R.; Post, C.; F. Walsh (2009). "Little egret (Egretta garzetta) and grey heron (Ardea cinerea) Using Bait for Fishing in Kenya ".Waterbirds.32(3): 450–452.doi:10.1675/063.032.0311.S2CID85622885.
  13. ^Robinson, S. (1994)."Use of bait and lures by green-backed herons in Amazonian Peru"(PDF).Wilson Bulletin.106(3): 569–571.JSTOR4163462.
  14. ^Dinsmore, James J. (1973). "Foraging Success of Cattle Egrets,Bubulcus ibis".American Midland Naturalist.89(1): 242–246.doi:10.2307/2424157.JSTOR2424157.
  15. ^abHilaluddin, Aisha S.; Khan, A.; Yahya, H.; Kaul, R. (2006)."Nesting ecology of Cattle Egrets and Little Egrets in Amroha, Uttar Pradesh, India"(PDF).Forktail.22.Archived fromthe original(PDF)on 2011-06-10.
  16. ^Kushlan, J. A. (2011).The terminology of courtship, nesting, feeding and maintenance in heronsArchived2019-10-24 at theWayback Machine.heronconservation.org
  17. ^Mehta, Kanishka; Koli, Vijay K.; Kittur, Swati; Sundar, K. S. Gopi (2024)."Can you nest where you roost? Waterbirds use different sites but similar cues to locate roosting and breeding sites in a small Indian city".Urban Ecosystems.27.
  18. ^McCracken, Kevin G.; Sheldon, Frederick H. (1998)."Molecular and osteological heron phylogenies: sources of incongruence"(PDF).Auk.115(1): 127–141.doi:10.2307/4089118.JSTOR4089118.
  19. ^Sheldon, Frederick H.; McCracken, Kevin G.; Stuebing, Keeley D. (1995)."Phylogenetic relationships of the zigzag heron (Zebrilus undulatus) and white-crested bittern (Tigriornis leucolophus) estimated by DNA-DNA hybridization "(PDF).Auk.112(3): 672–679.JSTOR4088682.
  20. ^Sheldon, Frederick H.; Jones, Clare E.; McCracken, Kevin G. (2000)."Relative Patterns and Rates of Evolution in Heron Nuclear and Mitochondrial DNA"(PDF).Molecular Biology and Evolution.17(3): 437–450.doi:10.1093/oxfordjournals.molbev.a026323.PMID10723744.Archived fromthe original(PDF)on 2006-09-07.
  21. ^Hackett SJ, Kimball RT, Reddy S, Bowie RC, Braun EL, Braun MJ, Chojnowski JL, Cox WA, Han KL, Harshman J, Huddleston CJ, Marks BD, Miglia KJ, Moore WS, Sheldon FH, Steadman DW, Witt CC, Yuri T (2008). "A Phylogenomic Study of Birds Reveals Their Evolutionary History".Science.320(5884): 1763–1768.Bibcode:2008Sci...320.1763H.doi:10.1126/science.1157704.PMID18583609.S2CID6472805.
  22. ^abcGill, Frank;Donsker, David;Rasmussen, Pamela,eds. (July 2023)."Ibis, spoonbills, herons, Hamerkop, Shoebill, pelicans".IOC World Bird List Version 13.2.International Ornithologists' Union.Retrieved19 September2023.
  23. ^abHruska, J.P.; Holmes, J.; Oliveros, C.; Shakya, S.; Lavretsky, P.; McCracken, K.G.; Sheldon, F.H.; Moyle, R.G. (2023). "Ultraconserved elements resolve the phylogeny and corroborate patterns of molecular rate variation in herons (Aves: Ardeidae)".Ornithology.140(2): ukad005.doi:10.1093/ornithology/ukad005.

Further reading[edit]

External links[edit]

Wikispecieshas information related toArdeidae.
Wikimedia Commonshas media related to:
Ardeidae(category)
Look upheronin Wiktionary, the free dictionary.
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