Theblack-crowned night heron (Nycticorax nycticorax) orblack-capped night heron[citation needed], commonly shortened to justnight heron inEurasia, is a medium-sizedheron found throughout a large part of the world, including parts of Europe, Asia, and North and South America. InAustralasia it is replaced by the closely relatedNankeen night heron (N. caledonicus), with which it hashybridised in the area of contact.
The black-crowned night heron wasformally described by the Swedish naturalistCarl Linnaeus in 1758 in thetenth edition of hisSystema Naturae. He placed it with herons, cranes and egrets in thegenusArdea and coined thebinomial nameArdea nycticorax, based on specimens from southern Europe.[2] It is now placed in the genusNycticorax that was described in 1817 by the English naturalistThomas Forster for this species.[3][4] The epithetnycticorax is fromAncient Greek and combinesnux,nuktos meaning "night" andkorax meaning "raven". The word was used by authors such asAristotle andHesychius of Miletus for a "bird of ill omen", perhaps an owl. The word was used by the Swiss naturalistConrad Gessner in 1555 and then by subsequent authors for a black-crowned night heron.[5][6]
N. n. nycticorax (Linnaeus, 1758) – Eurasia south to Africa and Madagascar and east to east Asia, Philippines and Indonesian Archipelago
N. n. hoactli (Gmelin, 1789) – southern Canada to northern Argentina and northern Chile; Hawaii
N. n. obscurus (Bonaparte, 1855) – central and southern Chile and southwest Argentina
N. n. falklandicus (Hartert, EJO, 1914) – Falkland Islands
In theFalkland Islands, the bird is calledquark, which is anonomatopoeia similar to its name in many other languages, likequa-bird in English,kwak in Dutch andWest Frisian,kvakoš noční inCzech,квак inUkrainian,кваква in Russian,vạc inVietnamese,kowak-malam inIndonesian,hoactli ("wactli") inNahuatl (cf. the scientific name of the New World subspecies),[6] andwaqwa inQuechua.
Adults have a black crown and back with the remainder of the body white or grey, red eyes, and short yellow legs. They have pale grey wings and white under parts. One to eight (mostly two to four) long slender white plumes, erected in greeting and courtship displays, extend from the back of the head. The sexes are similar in appearance although the males are slightly larger. Black-crowned night herons do not fit the typical body form of the heron family. They are relatively stocky with shorter bills, legs, and necks than their more familiar cousins, the egrets and "day" herons. Their resting posture is normally somewhat hunched but when hunting they extend their necks and look more like other wading birds. For a short period during courtship at the start of the nesting season, the legs of adults turn bright salmon-pink, and the bare skin around the eyes blue.[7][8]
Adult black-crowned night heron of subspeciesN. n. obscurus showing grey plumage.
The subspecies differ little; nominateN. n. nycticorax andN. n. hoactli are particularly similar in plumage (some authors have consideredN. n. hoactli a synonym of the nominate[8]), but the latter is on average slightly larger.N. n. obscurus is the most distinctive subspecies, clearly darker thanN. n. hoactli from further north in South America, butN. n. falklandicus is intermediate, with both paler and darker individuals occurring.[8]
Immature birds have dull grey-brown plumage on their heads, wings, and backs, with numerous pale "teardrop" spots. Their underparts are paler and streaked with brown. Second and third year birds attain plumages increasingly similar to adults, but lacking the white head plumes.[7] The young birds have orange eyes and duller yellowish-green legs. They are very noisy birds in their nesting colonies, with calls that are commonly transcribed asquok orwoc.
Measurements
N. n. nycticorax
N. n. hoactli
Length
58–65 cm (23–26 in)
58–66 cm (22.8–26 in)
Weight
male 600–800 g (21–28 oz) female 520–700 g (18–25 oz)
The breeding habitat is fresh and salt-waterwetlands throughout much of the world. The nominate subspeciesN. n. nycticorax breeds in Europe, Asia and Africa, subspeciesN. n. hoactli in North and South America from Canada as far south as northernArgentina andChile,N. n. obscurus in southernmost South America, andN. n. falklandicus in theFalkland Islands. Black-crowned night herons nest incolonies on platforms of sticks in a group of trees, or on the ground in protected locations such as islands or reedbeds. Three to eight eggs are laid.
This heron ismigratory in the northern parts of its range, but is otherwise resident (even in the coldPatagonia). European birds winter in Africa (with a few staying in southern Spain), central and east Asian birds winter in southern Asia, and North American birds winters in Mexico, the southern United States, Central America, and the West Indies.
A colony of the herons has regularly summered at theNational Zoo inWashington, D.C., for more than a century.[10] The birds also prominently live year-round in the shores around theSan Francisco Bay, with the largest rookery inOakland.[11] Their ever presence at Oakland'sLake Merritt and throughout the city's downtown area, as well as their resilience to the urban environment and displacement efforts, have led to them being named Oakland's official city bird.[11]
There are two archaeological specimens of the black-crowned night heron inGreat Britain. The oldest is from theRomanLondon Wall and the more recent from theRoyal Navy's late medieval victualling yards inGreenwich.[12] It appears in the Londonpoulterers' price lists as the Brewe, a bird which was thought to have been theEurasian whimbrel orglossy ibis, which has now been shown to refer to the black-crowned night heron, derived from the medieval FrenchBihoreau.[13] Black-crowned night heron may have bred in the far wetter and wider landscape of pre-modern Britain. They were certainly imported for the table so the bone specimens themselves do not prove they were part of the British avifauna. In modern times the black-crowned night heron is a vagrant (excluding the feral breeding colonies that were established atEdinburgh Zoo from 1950 into the start of the 21st century[14] and atGreat Witchingham in Norfolk, where there were eight pairs in 2003 but breeding was not repeated subsequently[15]). A pair of adults were seen with two recently fledged juveniles in Somerset in 2017, which is the first proven breeding record of wild black-crowned night herons in Great Britain.[16]
^abcCramp, S. (1977):The Birds of the Western Palearctic, p. 262–269. Oxford.ISBN0-19-857358-8
^abcdel Hoyo, J.; Elliott, A.; Sargatal, J., eds. (1992).Handbook of the Birds of the World. Vol. 1: Ostrich to Ducks. Barcelona, Spain: Lynx Edicions. p. 419.ISBN84-87334-10-5.
^Riehl, Christina (2001). "Black-Crowned Night Heron Fishes with Bait".Waterbirds: The International Journal of Waterbird Biology.24 (2):285–286.doi:10.2307/1522044.JSTOR1522044.
^Sitko, J.; Heneberg, P. (2015). "Composition, structure and pattern of helminth assemblages associated with central European herons (Ardeidae)".Parasitology International.64 (1):100–112.doi:10.1016/j.parint.2014.10.009.PMID25449288.
Blasco-Zumeta, Javier; Heinze, Gerd-Michael."Black-crowned Night Heron"(PDF).Identification Atlas of Aragon's Birds. Archived fromthe original(PDF) on 25 October 2018. Retrieved1 June 2018.
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