Heron
Herons | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Pelecaniformes |
Suborder: | Ardei |
Family: | Ardeidae Leach, 1820 |
Type genus | |
Ardea Linnaeus, 1758
| |
Genera | |
18 extant, see text | |
Global distribution of herons | |
Synonyms | |
Cochlearidae |
Herons are long-legged, long-necked, freshwater and coastal
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,
Although herons resemble birds in some other families, such as the
Name
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.[3]
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.[4]
The 1971
Another former name was heronshaw or hernshaw, derived from Old French heronçeau. Corrupted to handsaw, this name appears in
A possible further corruption took place in the Norfolk Broads, where the heron is often referred to as a harnser.Description
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 (10–12 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 can 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 backwards. The feet of herons have long, thin toes, with three forward pointing ones and one pointing backwards.[7]
The
Distribution and habitat
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 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 partially migratory; for example, the grey heron 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.[7]
Behaviour and ecology
Diet
The herons and bitterns are
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.[7]
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 the black heron, which forms a full canopy with its wings over its body.[11]
Some species of heron, such as the
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.[14]
Breeding
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.[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 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.[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 the little bittern and least bittern, only the male works on the nest.[7]
Some ornithologists have reported observing female herons attaching themselves to impotent mates, 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 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.[7]
Taxonomy and systematics
Analyses of the skeleton, mainly the
- tiger herons and the boatbill
- bitterns
- day herons and egrets, and night herons
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
The cladogram shown below is based on a
Ardeidae |
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As of July 2023 the IOC lists 72 species which are divided into 18 genera.[22]
- Subfamily Tigriornithinae
- Genus Taphophoyx (fossil, Late Miocene of Levy County, Florida)
- Genus Tigrisoma – typical tiger herons (three species)
- Genus Tigriornis– white-crested tiger heron
- Subfamily Cochleariinae
- Genus Cochlearius– boat-billed heron
- Genus
- Subfamily Agamiinae
- Genus Agamia– Agami heron
- Genus
- Subfamily Botaurinae
- Subfamily Ardeinae
- Genus Zeltornis (fossil, Early Miocene of Djebel Zelten, Libya)
- Genus Nycticorax – typical night herons (two living species, four recently extinct; sometimes includes Nyctanassa)
- Genus Nyctanassa – American night herons (one living species, one recently extinct)
- Genus Gorsachius – Asian and African night herons (four species)
- Genus Butorides – green-backed herons (three species; sometimes included in Ardea)
- Genus Pilherodius– capped heron
- Genus Zonerodius– forest bittern
- Genus Ardeola– pond herons (six species)
- Genus Bubulcus– cattle egrets (one or two species, sometimes included in Ardea)
- Genus Proardea (fossil)
- Genus Ardea– typical herons (11–17 species)
- Genus Syrigma– whistling heron
- Genus Egretta – typical egrets (7–13 species)
- Genus undetermined
- Easter Island heron, Ardeidae gen. et sp. indet. (prehistoric)
- Easter Island heron, Ardeidae gen. et sp. indet. (
- Fossil herons of unresolved affiliations
- "Anas" basaltica (Late Oligocene of Varnsdorf, Czech Republic)
- Ardeagradis
- Proardeola – possibly same as Proardea
- Matuku(Early Miocene of Otago, New Zealand)
Other prehistoric and fossil species are included in the respective genus accounts. In addition,
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White-faced heron (Egretta novaehollandiae), demonstrating the retracted neck that is typical of herons in flight.
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Bare-throated tiger heron (Tigrisoma mexicanum)
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Great bittern(Botaurus stellaris)
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Eastern great egret (Ardea modesta)
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The Wounded Heron by George Frederic Watts, 1837 (Watts Gallery)
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Heron pictured in the coat of arms of Priozersk, Russia
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Squacco heron from Egypt
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Heron in Zagreb Zoological Garden, Croatia
Symbolic meaning in mysticism
In Buddhism, a heron symbolizes purity, transformation and the wisdom of the Buddha. In addition, as a bird that transcends elements – earth, water and 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
- ^ 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
- ISBN 978-0-670-30044-0.
- ^ Harper, Douglas. "heron". Online Etymology Dictionary.
- ISBN 0-87779-001-9
- Library of Congress Catalogue Card Number76-188038
- ISBN 978-0141941868.
- ^ ISBN 978-84-87334-10-8.
- JSTOR 1368954.
- JSTOR 1368843.
- JSTOR 4083060.
- JSTOR 4080141.
- S2CID 85622885.
- JSTOR 4163462.
- JSTOR 2424157.
- ^ a b Hilaluddin, 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 from the original (PDF) on 2011-06-10.
- ^ Kushlan, J. A. (2011). The terminology of courtship, nesting, feeding and maintenance in herons Archived 2019-10-24 at the Wayback Machine. heronconservation.org
- ^ 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.
- JSTOR 4089118.
- JSTOR 4088682.
- PMID 10723744. Archived from the original(PDF) on 2006-09-07.
- S2CID 6472805.
- ^ Rasmussen, Pamela, eds. (July 2023). "Ibis, spoonbills, herons, Hamerkop, Shoebill, pelicans". IOC World Bird List Version 13.2. International Ornithologists' Union. Retrieved 19 September 2023.
- ^ .
Further reading
- Hancock, James & ISBN 0-06-011759-1
External links
- HeronConservation Heron Specialist Group of IUCN
- Heron videos on the Internet Bird Collection