The green heron (''Butorides virescens'') is a small

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north ...

and

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

. ''Butorides'' is from

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old Englis ...

''butor'' "bittern" and

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 pe ...

''-oides'', "resembling", and ''virescens'' is

Latin Latin (, or , ) is a classical language belonging to the Italic languages, 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 ...

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 In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all speci ...

(no matter which taxonomic arrangement is preferred) are extremely rare vagrants to western

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

—for example, a sighting in Pembrokeshire in 2018 was only the second recorded sighting in

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

; individuals from the Pacific coast of North America may similarly stray as far as

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

Description

The green heron is relatively small; adult body length is about . The neck is often pulled in tight against the body. Adults have a glossy, greenish-black cap, a greenish back and wings that are grey-black grading into green or blue, a

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrel ...

neck with a white line down the front, grey underparts and short yellow legs. The bill is dark with a long, sharp point. Female adults tend to be smaller than males, and have duller and lighter plumage, particularly in the breeding season. Juveniles are duller, with the head sides, neck and underparts streaked brown and white, tan-splotched back and wing coverts, and greenish-yellow legs and bill. Hatchlings are covered in down feathers, light grey above, and white on the belly. The green heron's call is a loud and sudden '; it also makes a series of more subdued ' calls. During courtship, the male gives a ' call with wide-open bill, makes noisy wingbeats and ' calls in flight, and sometimes calls ' to the female before landing again. While sitting, an ' courtship call is also given. Measurements: * Length: * Weight: * Wingspan:

Taxonomy

As noted above, this species was formerly included in ''B. striata'', which at that time was erroneously known as ''B. striatus''. The

Early Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...

''B. validipes'', whose fossil remains were discovered in Florida, might have been the ancestor of the green heron as the living species seems to replace the extinct relative in the fossil record. Subspecies distinction is uncertain at best. The color variation between populations is less pronounced than between birds of the same population. Migratory populations are longer-winged than those resident year-round, but this cannot be used to delimit subspecies as it is quite obviously a consequence of differing habits and can be expected to undergo

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

in unrelated populations of this species that just share the same habits. Thus, thorough molecular phylogenetic studies would be required to resolve the question of subspecies delimitation. The following subspecies are commonly listed, though the validity of most of them is seriously disputed: * ''Butorides virescens anthonyi'' ( Mearns, 1895) :Breeds in the United States west of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...

, south to northern Baja California Peninsula,

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

. Some resident, most migrate to western Mexico in winter. * ''Butorides virescens bahamensis'' ( Brewster, 1888) :

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the a ...

. Resident. * ''Butorides virescens frazari'' (Brewster, 1888) :Southern Baja California Peninsula, Mexico. Resident. * ''Butorides virescens maculata'' ( Boddaert, 1783) – formerly ''maculatus'' :Southernmost US through

to central

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...

. Resident. * ''Butorides virescens virescens'' ( Linnaeus, 1758) :Breeds from southeastern

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

to central and southern US east of the Rocky Mountains. Winters from southernmost US to northern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

. Much of the dispute hinges upon the distinctness of the Caribbean and Central American populations, the second

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

in this species to be described. To describe the two most extreme views, some authors assemble the bulk of the mainland population in the

but treat the parapatric populations as distinct subspecies, while others place all resident populations in ''maculata'' and all migratory ones in ''virescens''.

Ecology

The

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

of the green heron is small wetlands in low-lying areas. The species is most conspicuous during dusk and dawn, and if anything these birds are nocturnal rather than diurnal, preferring to retreat to sheltered areas in daytime. They feed actively during the day, however, if hungry or provisioning young. Shore-living individuals adapt to the rhythm of the tides. They mainly eat small fish, frogs and aquatic

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...

s, but may take any

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...

prey they can catch, including such animals like leeches,

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. T ...

s, dragonflies,

damselflies Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies, which constitute the other odonatan suborder, Anisoptera, but are smaller and have slimmer bodies. Most species fold the wings alo ...

, waterbugs, grasshoppers,

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

s, crayfish, prawns, mice, other

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

s, lizards, tadpoles and

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more ...

s. Some of the many fish eaten are: minnows, sunfish,

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Per ...

, eels and, in urban areas, goldfish. Green herons are intolerant of other birds – including conspecifics – when feeding and are not seen to forage in groups. They typically stand still on shore or in shallow water or perch upon branches and await prey. Sometimes they drop food, insects, or other small objects on the water's surface to attract fish, making them one of the few known tool-using species. This feeding method has led some to title the green and closely related striated heron as among the world's most intelligent birds. They are able to hover briefly to catch prey. The northern population moves to its breeding ranges during March and April; near the northernmost limit of the green heron's range, breeding is well underway by the end of May. The migration to the winter quarters starts in September; by late October, the birds are absent from regions where they do not stay all year. At least the northward migration does not seem to be affected by

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

; birds appear in their breeding ranges at the same time they did 100 years ago. Individuals of non-migratory populations abandon their territories after breeding season to roam about the region. They may or may not return to the previous year's breeding location, depending on whether they found better habitat during these wanderings. In these populations, the breeding season is determined by rainfall and consequent prey availability. Green herons are seasonally monogamous. The pairs form in the breeding range, after an intense courtship display by the males, who select the nesting sites and fly in front of the female noisily and with puffed-up head and neck plumage. They nest in

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' ...

and

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

patches, over water or in plants near water. Nests are a platform of sticks, often in shrubs or trees, sometimes on the ground. Locations in trees are preferred, with some nests built up to off the ground although heights of several meters are more common. Rarely, large numbers of these birds congregate in heronries for nesting. The clutch is usually 2–6 pale green eggs, which are laid in 2-day intervals (though the second egg may be laid up to 6 days later than the first). After the last egg has been laid, both parents incubate for about 19–21 days until hatching, and feed the young birds. The frequency of feedings decreases as the offspring near

fledging Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable ...

. The young sometimes start to leave the nest at 16 days of age, but are not fully fledged and able to fend for themselves until 30–35 days old. Sometimes – particularly in the

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

parts of its range – the green heron breeds twice a year.

Tool use

Green herons are one of the few species of bird known to use tools. In particular, they commonly use bread crusts, insects, or other items as bait. The bait is dropped onto the surface of a body of water to lure fish. When a fish takes the bait, the green heron then grabs and eats the fish. When green herons catch large frogs, they drown them before swallowing them whole.

Gallery

File:Green Heron nestlings.jpg, Nestlings Image:Green Heron4.jpg, Subadult retaining some juvenile plumage File:Green_heron_(Butorides_virescens_virescens)_young_adult.jpg, Young adult ''B. v. virescens'' File:Green Heron at Dunes Golf Course, Sanibel.jpg, Breeding plumage File:Green Heron Adult Prado Regional Park.jpg, Adult File:Green Heron With Crest Raised Key West 16 May 2020.jpg, Adult Green heron in PP (14296).jpg, Hunting in New York

References

External links

''Butorides virescens'' – Green heron at Animal Diversity Web

– USGS Patuxent Bird Identification InfoCenter
Green heron at eNature.com

Field Guide on Flickr
*
YouTube video of a green heron fishing

YouTube Video of a Green Heron drowning a frog before eating it!

Bermuda Dept. of Environment and Natural Resources green heron page
* * * {{Taxonbar, from=Q498228 Green heron Green heron Birds of the United States Birds of Canada Birds of Panama Birds of Puerto Rico Birds of the Dominican Republic Birds of Trinidad and Tobago Tool-using animals Birds described in 1758 Taxa named by Carl Linnaeus Extant Pleistocene first appearances Taxobox binomials not recognized by IUCN