About 21 extant, see text
Global distribution of herons
The Herons are the 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
1 Description 2 Distribution and habitat 3 Behaviour and ecology
3.1 Diet 3.2 Breeding
4 Name 5 Taxonomy and systematics 6 References 7 Further reading 8 External links
The neck of this yellow bittern is fully retracted.
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 little bittern, which can measure
under 30 cm (12 in) in length, although all the species in
Pacific reef heron
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. Distribution and habitat
Lava herons are endemic to the Galápagos Islands, where they feed on fish and crabs in the intertidal and mangrove areas.
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. Behaviour and ecology Diet
A great egret manipulating its prey, a lizard, prior to swallowing
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.
Black herons holding 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 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. Breeding
The larger bitterns, like this American 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 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.
Some ornithologists have reported observing female herons attaching
themselves to impotent mates, then seeking sexual gratification
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,
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.
Compact Edition of the Oxford English Dictionary
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
Easter Island heron, Ardeidae gen. et sp. indet. (prehistoric)
Calcardea (Paleocene) Xenerodiops (Early Oligocene of Fayyum, Egypt) "Anas" basaltica (Late Oligocene of Varnsdorf, Czech Republic) Ardeagradis Proardeola – possibly same as Proardea Matuku otagoense (Early Miocene of Otago, New Zealand)
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
Eastern great egret (Ardea modesta)
^ McKilligan, Neil (2005). Herons, Egrets and Bitterns: Their Biology
and Conservation in Australia. CSIRO Publishing. p. 2.
ISBN 9780643091337. ISSN 1447-8781. Retrieved 8 February
^ a b c d e f g h i j k l Martínez-Vilalta, Albert; Motis, Anna
(1992). "Family Ardeidae (herons)". In del Hoyo, Josep; Elliott,
Andrew; Sargatal, Jordi. Handbook of the Birds of the World. Volume 1:
Ostriches to Ducks. Barcelona: Lynx Edicions. pp. 376–403.
^ Itoh, Singi (1991). "Geographical Variation of the Plumage
Polymorphism in the eastern reef heron (
Hancock, James & Elliott, Hugh (1978) The Herons of the World; with paintings by Robert Gillmor and Peter Hayman, and drawings by Robert Gillmor. London: London Editions ISBN 0-905562-05-4; New York: Harper & Row ISBN 0-06-011759-1
Look up heron in Wiktionary, the free dictionary.
Wd: Q18789 ADW: Ardeidae EoL: 8013 EPPO: 1ARDEF Fauna Europaea: 10741 Fossilworks: 39541 GBIF: 3685 ITIS: 174771 NCBI: 8899 WoRMS: 148747