green heron

The green heron is relatively small; adult body length is about {{convert|44|cm|0|abbr=on}}. 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 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 {{not a typo|kyow}}; it also makes a series of more subdued {{not a typo|kuk}} calls. During courtship, the male gives a {{not a typo|raah-rahh}} call with wide-open bill, makes noisy wingbeats and {{not a typo|whoom-whoom-whoom}} calls in flight, and sometimes calls {{not a typo|roo-roo}} to the female before landing again. While sitting, an {{not a typo|aaroo-aaroo}} courtship call is also given.

Measurements:{{Cite web|title=Green Heron Identification, All About Birds, Cornell Lab of Ornithology|url=https://www.allaboutbirds.org/guide/Green_Heron/id|access-date=2020-09-26|website=www.allaboutbirds.org|language=en}}

• Length: {{convert|16.1|-|18.1|in|cm|abbr=on}}
• Weight: {{convert|8.5|oz|g|abbr=on}}
• Wingspan: {{convert|25.2|-|26.8|in|cm|abbr=on}}

As noted above, this species was formerly included in B. striata, which at that time was erroneously known as B. striatus. The Early Pleistocene 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 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, south to northern Baja California Peninsula, Mexico. Some resident, most migrate to western Mexico in winter.

• Butorides virescens bahamensis (Brewster, 1888)

:Bahamas. Resident.

• Butorides virescens frazari (Brewster, 1888)

:Southern Baja California Peninsula, Mexico. Resident.

• Butorides virescens maculata (Boddaert, 1783) – formerly maculatus

:Southernmost US through Central America to central Panama, Caribbean. Resident.

• Butorides virescens virescens (Linnaeus, 1758)

:Breeds from southeastern Canada to central and southern US east of the Rocky Mountains. Winters from southernmost US to northern South America.

Much of the dispute hinges upon the distinctness of the Caribbean and Central American populations, the second taxon in this species to be described. To describe the two most extreme views, some authors assemble the bulk of the mainland population in the nominate subspecies but treat the parapatric populations as distinct subspecies, while others place all resident populations in maculata and all migratory ones in virescens.

In Trinidad and Tobago and in central Panama, it overlaps slightly in range with the closely related striated heron and hybridizes with it; hybrids are intermediate between the two species, generally grayer below than typical green herons.{{cite web | title=View of Variation and hybridization in the Green Heron (Butorides virescens) and Striated Heron (B. striata) in Trinidad and Tobago, with comments on species limits | website=Journal of Caribbean Ornithology | url=https://jco.birdscaribbean.org/index.php/jco/article/view/271/187 | access-date=2025-03-28}}{{cite web | last=Hayes | first=Floyd E. | last2=Weidemann | first2=Douglas E. | last3=Baumbach | first3=Dustin S. | last4=Tkachuck | first4=Richard D. | last5=Tkachuck | first5=Cindy M. | title=Variation and hybridization in Green Heron (Butorides virescens) and Striated Heron (B. striata) in central Panama, with comments on species limits | journal=North American Birds | volume=67 | issue=1 | date=2013-02-01 | url=https://www.researchgate.net/publication/259868747_Variation_and_hybridization_in_Green_Heron_Butorides_virescens_and_Striated_Heron_B_striata_in_central_Panama_with_comments_on_species_limits | access-date=2025-03-28 | page=2–6}}

File:Brooklyn Museum - Green Heron - John J. Audubon.jpg

The habitat and foraging area of the green heron includes riparian zones, wetlands, ponds, and lakes, as well as human-made canals and ditches.{{Cite journal |last1=Moore |first1=Amanda A. |last2=Green |first2=M. Clay |last3=Huffman |first3=David G. |last4=Simpson |first4=Thomas R. |date=2016 |title=Green Herons (Butorides virescens) in an Urbanized Landscape: Does Recreational Disturbance Affect Foraging Behavior? |url=https://www.jstor.org/stable/44840286 |journal=The American Midland Naturalist |volume=176 |issue=2 |pages=222–233|doi=10.1674/0003-0031-176.2.222 |jstor=44840286 }} Green herons do not exhibit a particular preference for diurnal or nocturnal foraging, often engaging in both. Shore-living individuals adapt to the rhythm of the tides.{{Citation needed|date=March 2024}} They mainly eat small fish, frogs and aquatic arthropods, but may take any invertebrate or vertebrate prey they can catch, including such animals like leeches, earthworms, dragonflies, damselflies, waterbugs, grasshoppers, spiders,{{cite web |url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/images/Butorides_viridescens%20-%20Green%20Heron.pdf |title=Butorides virescens (Green Heron) |work=The Online Guide to the Animals of Trinidad and Tobago |publisher=University of the West Indies}} crayfish,{{cite web | url=https://animaldiversity.org/accounts/Butorides_virescens/ | title=Butorides virescens (Green heron) | website=Animal Diversity Web }} prawns, mice, other rodents, lizards, tadpoles and snakes. Some of the many fish eaten are: minnows, sunfish, catfish, perch, 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. They are able to hover briefly to catch prey. Green herons have been observed using captured prey (e.g. mayflies) or other objects (bread, feathers) to "bait-fish" – using a lure on the water's surface to attract fish.{{Cite journal |last1=Davis Jr. |first1=William E. |last2=Zickefoose |first2=Julie |date=1998 |title=Bait-fishing by Birds: A Fascinating Example of Tool Use |journal=Bird Observer |volume=26 |issue=3 |pages=139–143}} This bait-fishing behavior is common among herons.

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; 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 and swamp 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 {{convert|20|m|abbr=on}} 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,{{cite web| author = Cornell Lab of Ornithology| url = http://www.allaboutbirds.org/guide/Green_Heron/lifehistory | title = Green Heron | access-date = 2010-04-08}} which are laid in two-day intervals (though the second egg may be laid up to six days later than the first).{{cite web| author = Cornell Lab of Ornithology| url = http://bna.birds.cornell.edu/bna/species/129/articles/breeding | title = Green Heron | access-date = 2011-05-11}} After the last egg has been laid, both parents incubate for about 19–21 days until hatching, and feed the young birds.{{cite web| author = Seattle Audubon Society| url = http://www.seattleaudubon.org/birdweb/bird_details.aspx?id=46| title = Green Heron| access-date = 2010-04-08| archive-date = 2016-03-04| archive-url = https://web.archive.org/web/20160304203554/http://www.seattleaudubon.org/birdweb/bird/green_heron| url-status = dead}} The frequency of feedings decreases as the offspring near fledging. 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 parts of its range – the green heron breeds twice a year.

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.{{Cite web |title=Green Heron Overview, All About Birds, Cornell Lab of Ornithology |url=https://www.allaboutbirds.org/guide/Green_Heron/overview |access-date=2022-05-22 |website=www.allaboutbirds.org |language=en}}

File:Green Heron nestlings.jpg|Nestlings

File: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, with neck retracted

File:Green Heron Adult Prado Regional Park.jpg|Adult

File:Green Heron With Crest Raised Key West 16 May 2020.jpg|Adult

File:Green heron in PP (14296).jpg|Hunting in New York

File:Green heron (Butorides virescens) in flight Peten.jpg|in Guatemala

File:Butorides virescens 070506 GWADA.jpg|Subspecies B. v. maculata with neck extended

File:20230912 green heron point meadows keeney cove PND03302.jpg|Juvenile, Glastonbury, CT USA

{{Reflist|30em|refs=

Dewey, T. & Butzbaugh, J. (2001): Animal Diversity Web: [http://animaldiversity.ummz.umich.edu/site/accounts/information/Butorides_virescens.html Butorides virescens]. Retrieved 2008-FEB-12.

{{cite journal

|author=Henninger, W.F.

|year=1906

|title= A preliminary list of the birds of Seneca County, Ohio|journal=Wilson Bulletin|volume=18|issue=2|pages= 47–60

|url=http://sora.unm.edu/sites/default/files/journals/wilson/v018n02/p0047-p0060.pdf}}

Jutglar, Francesc (1992): 33. Green-backed Heron. In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 1: Ostrich to Ducks): 417, plate 28. Lynx Edicions, Barcelona. {{ISBN|84-87334-10-5}}

{{cite web

| url =https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=824525

| title = ITIS Report: Butorides virescens

| publisher = Integrated Taxonomic Information System

| access-date = 28 August 2014}}

• National Geographic Society (2002): Field Guide to the Birds of North America. National Geographic, Washington DC. {{ISBN|0-7922-6877-6}}

Ohio Ornithological Society (2004): [http://www.ohiobirds.org/publications/OBRClist.pdf Annotated Ohio state checklist] {{webarchive|url=https://web.archive.org/web/20040718101517/http://www.ohiobirds.org/publications/OBRClist.pdf |date=2004-07-18 }}.

}}

{{Commons category|Butorides virescens|Green heron}}

{{Wikispecies|Butorides virescens}}

• [http://animaldiversity.ummz.umich.edu/site/accounts/information/Butorides_virescens.html Butorides virescens – Green heron at Animal Diversity Web]
• [http://www.mbr-pwrc.usgs.gov/id/framlst/i2010id.html Green heron – Butorides virescens] – USGS Patuxent Bird Identification InfoCenter
• [https://web.archive.org/web/20061124234930/http://www.enature.com/fieldguides/detail.asp?recnum=BD0110 Green heron at eNature.com]
• [https://www.flickr.com/groups/birdguide/pool/tags/Butorides%20virescens/ Field Guide on Flickr]
• {{ITIS |id=174793 |taxon=Butorides virescens |access-date=9 February 2006}}
• [https://www.youtube.com/watch?v=UNTw7GH325U&NR=1 YouTube video of a green heron fishing]
• [https://www.youtube.com/watch?v=sOmlQENizoc YouTube Video of a Green Heron drowning a frog before eating it!]
• [http://www.environment.bm/green-heron/ Bermuda Dept. of Environment and Natural Resources green heron page]
• {{InternetBirdCollection|green-backed-heron-butorides-striatus|Green-backed heron}}
• {{VIREO|Green+Heron|Green heron}}
• {{NeotropicalBirds|grnher|Green heron}}

{{Taxonbar|from=Q498228}}

Green heron

Green heron

Category:Birds of the United States

Category:Birds of Canada

Category:Birds of Panama

Category:Birds of Puerto Rico

Category:Birds of the Dominican Republic

Category:Birds of Trinidad and Tobago

Category:Tool-using animals

Category:Birds described in 1758

Category:Taxa named by Carl Linnaeus

Category:Extant Pleistocene first appearances

Category:Taxobox binomials not recognized by IUCN