Gorsachius magnificus (Ogilvie-Grant)
Nycticorax magnifica Ogilvie-Grant, 1899. Ibis, p.586: Five Finger Mountain, Hainan.
The White-eared Night Heron is a medium brown heron with a brown streaked breast and a white patch on the side of the head.
ADULT: The adult male has a black crown with a brown black crest. The rest of the head is distinctly patterned in white and brown patches. A brown black cheek patch extending from the crown to the bill is separated from the cap by a white wedge extending back from the eye – the white ear of the species’ common English name. A smaller white line descends diagonally from the eye. The chin is white and the upper throat also is white, but dusky centres to the feathers results in a mottled appearance. The irises are yellow, and the lores and skin around the eye are yellow green forming a conspicuous pale patch in front of the eye. The bill is basically dark, the upper bill being black and lower bill having a green yellow tinge at the base.
The front of the throat is vertically streaked down the middle, blacker towards the head and browner onto the breast. Three broad vertically oriented patches cover the area of the side to back of the neck: lateral to the dark-mottled central throat stripe is a white line descending from the white of the lower cheek, lateral to that is a broad black brown line ascending from the dark shoulder, and lateral to that is a broad buff yellow patch merging to chestnut orange at the back.
The upper parts are dark grey brown with a purple tinge, sometimes with a few white spots on the lower back. Flight feathers are slate. The brown stripe on the fore neck merges on the breast onto the mottled brown and white undersides. Thighs are dark reddish-brown. The legs are green.
VARIATION: In the female, the color of the head and neck is less prominent; the back and wings are more mottled, streaked, and spotted with white especially on the upper wing. The crest feathers are shorter than the male’s
JUVENILE: The immature has brown instead of brown black feathering spotted with buff or white. The back and upper wings are brown with heavy buff or white spotting.
CHICK: The chick is undescribed.
VOICE: Nothing is known of the voice of this species
WEIGHTS AND MEASUREMENTS: Length: About 54 cm.
The White-eared Night Heron is identified by its dark base color contrasting with white ears and white throat, and by its short bill. It is distinguished from the Malayan Night Heron by its tricolored neck (not rufous), dark (not chestnut) sides, and slate (not black) flight feathers. It is distinguished from the Black Bittern by shorter, thicker bill, stouter appearance, and shorter neck.
The White-eared Night Heron is related to the Japanese Night Heron, Malayan Night Heron, and the larger night herons. The relationships among the night herons remain unclear.
RANGE AND STATUS
The present known range of this species is confined to China,
BREEDING RANGE: This is a species with the most restricted known breeding range of any heron. Surveys conducted in 1999-2001 have clarified the current status. These have been organized through the collaboration of the Heron Specialist Group and Kadoorie Farm & Botanic Garden (KFBG), a conservation charity based in Hong Kong (KFBG, H. Hafner, and O. Pineau pers. com.). Based on these surveys at present, there are known two breeding site in the world, both located in south Guangxi Province, and one other area where breeding is strongly suspected, located in neighbouring Guangdong Province.
MIGRATION: It is most likely that this species is sedentary (BirdLife 2001). However information is very uncertain. There are winter and spring records from its most recent breeding area in south China (Hubei, Fujian, Guangdong, Guangxi). There also is a suggestion that dispersal occurred to the north prior to southern movement and that Hainan is or was once a wintering area for birds from further north. Of course given the population’s precarious position, its presence in Hainan has not been documented in recent years. There is one record from north Vietnam, which is either a straggler or an indication of prior wintering area.
STATUS: Very few individuals have been reported over the past 30 years. Of the two known breeding sites, one near Fusui is highly degraded and is unlikely to support the heron for much longer. In the early 1990’s the species was present in Hubei Province, in the Shennongjia Nature Reserve, but a re-examination of the site in 2001 revealed that what was prime habitat has been converted into a reservoir, and both the habitat and species have disappeared (KFBG, O. Pineau, and H. Hafner pers. com.). In 2000 and again in 2001, the bird was seen in Guangdong Province in the Chebaling Nature Reserve suggesting another breeding site exists there. Since 1990, there have been only 7 confirmed observation locations; but, other than noted above, it has not been observed in recent years in other parts of its historic range in south China or Hainan (Zhou 1996, Fellows et al. 2001, Gao et al. 2000, BirdLife International 2001, Hafner pers. com.). There are no population figures, but the world population numbers fewer than 20-50 birds. Certain remote areas in south China not yet surveyed need to be visited in a near future. In these forested mountain habitats difficult to access, isolated breeding sites may have gone unnoticed so far. This is the most endangered of all the herons (Kushlan and Hafner 2000).
The White-eared Night Heron is a forest bird. Optimal habitat appears to be extensive, dense, primary forests with streams and adjacent marshes. It currently is observed only in mid-altitude mountains and has not been found higher than 1300 m. However, it likely was originally also a lowland species, and its current restriction to hilly areas is probably because there are no remaining lowland forests (Fellowes et al. 2001).
Given that very little pristine habitat remains within the historic range of the species, it is observed primarily in degraded habitats in and near forest reserves. Recent observations have been near streams, a reservoir, and rice fields, all feeding sites located within 40 km of subtropical forests. These observations do not necessarily suggest that it can survive long term in altered environments, but rather that it has been forced into these sites as more appropriate habitat is now lacking (BirdLife 2001).
This is a very poorly known species. Observations of the species’ foraging are few (Caldwell and Caldwell 1931). Herons have been reported as feeding singly or in isolated pairs feeding on the ground in ways likened to a bittern. They roost high in trees. All evidence suggests that it feeds primarily at night, as it has been observed flying from roosts in the evening (Fellowes et al. 2001.). However daytime activity has also been reported (Zhou 1994). The diet includes fish, shrimp and insects, but is very little documented (Zhou 1994).
Nearly nothing is known about the breeding biology of this species. Various records of nesting activity indicate it nests in trees including oaks (Quercus), pines (Pinus), bamboo (although a nest was not found) and, likely, broad leafed trees (Caldwell and Caldwell 1931, BirdLife 2001). Information on nesting by this species is confounded by indications that it nested with Malayan Night Herons. Presumed nests were very near the tops of the trees, 4 –10 m above the ground near the trunks. Presumed nests were simple flat platforms (Fellows et al. 2001).
With nothing known about nesting, there is also no information on population biology.