''Gorsachius'' is a genus of Old World night herons typically found near water in forested regions. These are medium-sized

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 ''Ixobrychus ...

s which are migratory in the colder parts of their ranges, but otherwise resident. They are the least known, most strictly

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

, smallest and overall rarest night herons. Three of the four species are found in

East East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fa ...

South South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...

and

South-east Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

, while the last species, the white-backed night heron, is found in

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

. The Japanese and Malayan night herons resemble each other, being relatively short-billed and overall brown with a dark line from the throat to the upper belly. The larger white-eared and white-backed night herons are darker, with distinctive white markings on the face and neck in the former, and an entirely black head in the latter. Their behavior, especially that of the white-eared night heron, is relatively poorly known compared to that of other night herons, but they nest alone or in small groups, and a clutch of two to five

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s has been recorded. While generally nocturnal and

crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of daylig ...

, they have been recorded feeding during the day in clouded weather. They are skulking, and known to feed on crabs,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

, fish, insects, frogs and other small animals.

Taxonomy

These night herons were formerly placed in the genus ''

Nycticorax ''Nycticorax'' is a genus of night herons. The name ''Nycticorax'' means "night raven" and derives from the Ancient Greek νύκτος, ''nuktos'' "night" and κοραξ, ''korax'', "raven". It refers to the largely nocturnal feeding habits of ...

'', but today all major authorities recognize them as separate. In addition to the species listed below, the rufous or nankeen night heron has been placed in ''Gorsachius'', but today all major authorities place it in ''Nycticorax''. The four night herons in this genus are all

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

References

* Martínez-Vilalta, A., & A. Motis (1992). Family Ardeidae (Herons). pp. 376–429 in: del Hoyo, J., A. Elliott, & J. Sargatal. eds (1992). ''

Handbook of the Birds of the World The ''Handbook of the Birds of the World'' (HBW) is a multi-volume series produced by the Spanish publishing house Lynx Edicions in partnership with BirdLife International. It is the first handbook to cover every known living species of bird. T ...

.'' Vol. 1. Ostrich to Ducks. Lynx Edicions, Barcelona. {{Taxonbar, from=Q135951 Bird genera Taxa named by Charles Lucien Bonaparte