Japanese Night Heron Gorsachius goisagi Scientific name definitions

48–49 cm; 527 g (one male); wingspan 87–89 cm (1 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ). Similar to G. melanolophus, but lacks black cap and long crest, has darker drabber brown head , neck and upper body (richer chestnut-brown in G. melanolophus) (2 Sykes, B.R. (1996). The status and identification of Gorsachius herons in southern Taiwan. Bull. Oriental Bird Club. 23: 57–58. Close ); flanks less mottled and remiges  lack white tips (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); bill shorter and stouter. Bill possibly all green-black during breeding season, otherwise dark brown on upper mandible with yellow lower mandible (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); facial skin changes from yellow to blue in breeding season (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); iris  pale yellow with yellowish-green orbital ring (1 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ); tarsi dark yellowish green (1 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ). Juvenile  has crown blackish or dark brown and is less rufous on rest of head ; neck more spotted and streaked chestnut, wing-coverts paler and tipped buff (forming obvious wingbar in flight), undertail-coverts white, and has off-white lores and yellow eyering (1 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close , 4 Lamont, A.R. (2014). The description and behaviour of a juvenile Japanese Night Heron Gorsachius goisagi in Shanghai, China. BirdingASIA. 21: 70. Close ).

Breeds in S Japan on Honshu, Shikoku and possibly Kyushu; recently found breeding in Jeju Is, S Korea (5 Oh Hongshik, Kim Youngho and Kim Namkyu (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science 9(2): 131–134. Close ); one breeding report from Taiwan, and has been recorded in spring and summer in Russia (Primorye and Sakhalin). Winters from Ryukyu Is to Philippines.

Rivers and swamps in thickly forested areas, also farms and rice paddies (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) and bamboo forest on migration (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), and in lightly wooded areas close to cultivation in winter (6 Collins, A.R. (2017). Japanese Night Heron Gorsachius goisagi on Mount Talomo, Mindanao, Philippines. BirdingASIA. 28: 82–84. Close ), generally occurring in low parts of mountains from 50 m to 240 m, although it has been reported to 1100 m in Indonesia (7 Robson, C. (2014). From the field. BirdingASIA. 21:121–127. Close ), 1500 m in Japan and generally to 1350 m in the Philippines, with two records on Luzon from as high as 2400 m (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Habitual skulker in dense undergrowth.

Some birds sedentary, but vast majority of population seems to migrate S in Sept/Oct, returning in early Apr, although Mar records exist for Honshu  . Main wintering area appears to be Philippines, but also recorded as non-breeding visitor to Indonesia, rare winter visitor and passage migrant on Taiwan (2 Sykes, B.R. (1996). The status and identification of Gorsachius herons in southern Taiwan. Bull. Oriental Bird Club. 23: 57–58. Close ), and vagrant to Brunei (Oct 1985 (8 Elkin, J.A. (1993). Japanese Night-Heron Gorsachius goisagi, a species new to Borneo. Forktail. 8: 154–155. Close ), with perhaps same bird again Nov 1988) (9 Mann, C. F. (2008). The Birds of Borneo: An Annotated Checklist. B.O.U. Checklist 23. British Ornithologists’ Union, and British Ornithologists’ Club, Peterborough. Close ), Sulawesi, Halmahera, Seram (Jul 2013) (7 Robson, C. (2014). From the field. BirdingASIA. 21:121–127. Close ) and Sumatra (Feb 2004) (10 Iqbal, M. and Takari, F. (2006). Probable first record of Japanese Night-heron Gorsachius goisagi for Sumatra. Kukila. 13: 77–78. Close ), with single record on Palau, in W Caroline Is (Jan 1932) (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ). Improved awareness of identification criteria for immatures has led to a marked increase in records from Philippines. Record of exceptionally early migrant on Palawan (Philippines) on 5 Aug, which in following year was recovered in S Honshu (Japan) on 28 Apr, while there is also another Philippine record, from Mindanao, dated 14 Aug (12 Robson, C. (2015). From the field. BirdingASIA 24:144–148. Close ). All other records in Philippines dated Oct–May (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ), although it has been suggested that some occasionally summer there (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Occasional records to N of breeding range on Hokkaido and Sado (N Japan), and also Primorye and Sakhalin (off SE Ussuriland), mainly in spring (especially May) (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ). Sometimes diurnal during migration, when recorded also in Hong Kong and in coastal mainland China (mainly late Apr to mid May, and Nov) (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ).

Very little known. Apparently mainly crabs and other crustaceans; also insects, ground and scarabid beetles, earthworms (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), snails, cicadas and small fish; perhaps also small reptiles and a loach (Paramisgurnus dabryanus) has also been recorded (4 Lamont, A.R. (2014). The description and behaviour of a juvenile Japanese Night Heron Gorsachius goisagi in Shanghai, China. BirdingASIA. 21: 70. Close ). Diet at nest in South Korea included adult insects and larvae (Graptopsaltria nigrofuscata and Gryptotympana dubia, Cicadidae, Pterostichus sp. and Nicrophorus sp., Carabidae), earthworms (Lumbriculida sp.) and snails (mainly Nesiohelix samarangae) (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ). Walks slowly along watercourses or around pools, but also forages on dry ground  , rarely in open (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). In a study in Japan, land snails, freshwater crabs, ground, and scarabid beetles were the major prey items found in the pellets, whereas no fish were detected, indicating that the birds mainly forage on soil animals on the forest floor (14 Kawakami, K., Uchida, H. and Fujita, M. (2005). Diet of the Japanese Night Heron Gorsachius goisagi in Japan. Orn. Science. 4: 173–177. Close ). Solitary or in small, loose flocks. Generally nocturnal or crepuscular (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), but sometimes feeds during day when conditions are dull and cloudy.

Gives croaking “buo, buo” when feeding or at nest (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), slow, repetitive and somewhat owl-like, mainly given early evening and sometimes on migration; also rendered “bwoo bwoo bwoo” (1 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ).

Very little known. Eggs recorded in May–Jun and Jul (latter perhaps second or replacement clutch) (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ). Solitary or in small groups. Nests in dense foliage 7–20 m above ground (mean 10·6 m in 16·5 m high trees in recent Japanese study) (15 Ishikawa, M., Hamaguchi, H., Konishi, K., Fujita, K., Oshika, H. and Kawakami, K. (2012). The nesting tree and location environment of Japanese Night Heron Gorsachius goisagi in the West Mikawa area of Aichi Prefecture, Japan. Jap. J. Orn.. 61(2): 289–295. Close ), with more than 40% in Prunus spp. in one study (15 Ishikawa, M., Hamaguchi, H., Konishi, K., Fujita, K., Oshika, H. and Kawakami, K. (2012). The nesting tree and location environment of Japanese Night Heron Gorsachius goisagi in the West Mikawa area of Aichi Prefecture, Japan. Jap. J. Orn.. 61(2): 289–295. Close ), but also conifers (cedars Cryptomeria, cypresses Chamaecyparis) (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), and other deciduous trees (oaks Quercus, zelkovi Zelkova and chestnut Castanea) (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); once mulberry (Morus bombycis) (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ); nests sometimes in relatively close proximity (250–500 m) (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) and appears to prefer to nest at bottom, or on lower slopes, of valleys (15 Ishikawa, M., Hamaguchi, H., Konishi, K., Fujita, K., Oshika, H. and Kawakami, K. (2012). The nesting tree and location environment of Japanese Night Heron Gorsachius goisagi in the West Mikawa area of Aichi Prefecture, Japan. Jap. J. Orn.. 61(2): 289–295. Close ); nest is flimsy stick platform on more or less horizontal branch (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), typically 1–4 m from main trunk (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ). One Korean nest was constucted mainly of sticks from following trees, Styrax japonica, Cryptomeria japonica and Morus bombycis (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ). Clutch 3–4 dull white (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) eggs, size 47·5 mm × 37 mm (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); incubation 17–27 days, by both sexes (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ); fledging 35–37 days (once 42 days) (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ); feeding rates apparently vary, at Korean nest 5–6 times daily 30 days after hatching, and twice daily 35 days after hatching (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ).

ENDANGERED. Overall population estimated at 600–1700 individuals within an overall range of 35,800 km², but this may be an underestimate. Only six confirmed and 15 possible breeding sites in Japan (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), where considered uncommon to rare and very local throughout, and suitable habitat now extremely scarce as a result of deforestation and conversion to plantations (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); it was apparently locally common in Japan until 1970s, but by the 1980s and 1990s had disappeared from many former breeding sites (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Little information available on status and general biology, due mainly to dense, tangled habitat, together with nocturnal habits, but 26 nests were found in West Mikawa area of Aichi Prefecture in 2009–2010 (15 Ishikawa, M., Hamaguchi, H., Konishi, K., Fujita, K., Oshika, H. and Kawakami, K. (2012). The nesting tree and location environment of Japanese Night Heron Gorsachius goisagi in the West Mikawa area of Aichi Prefecture, Japan. Jap. J. Orn.. 61(2): 289–295. Close ). Marked decline in last 30 years, to which hunting and introduced predators (e.g. Siberian weasal Mustela sibirica) (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ) may also have contributed (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); in 1957 still considered not uncommon on Miyake jima, to S of Tokyo; seems to have been relatively common in places at beginning of century, as eggs and skins were sold cheaply; one such site was near what is now Tokyo’s main airport. None recorded in Asian Waterfowl Census, Jan 1990. Recently discovered breeding once in Taiwan (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) (perhaps regularly) (16 Fang, W.-H. (2004). Threatened birds in Taiwan. BirdingASIA 2: 61–65. Close ) and on Jeju I off South Korea (13 Oh, H., Kim, Y. and Kim, N. (2010). First breeding record of Japanese Night Heron Gorsachius goisagi in Korea. Orn. Science. 9(2): 131–134. Close ). Uncommon winter visitor to Philippines, where deforestation must also be considered primary threat (3 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), but records increasing due to better knowledge of species’ non-adult plumages and the archipelago appears to its main wintering area; just four records on Sulawesi and two on Halmahera (11 Collar, N. J., A. V. Andreev, S. Chan, M. J. Crosby, S. Subramanya, and J. A. Tobias, Editors (2001). Threatened Birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, UK. Close ). Apparently just two records from mainland China since early 1960s, one of two birds at Wuyuan in Jiangxi Province in Apr 2006 and a taxidermy specimen in Haiyan county, Zhejiang province, in Feb 2010 and apparently purchased in Haining city in Apr 1998.