White-eared Night-Heron

Gorsachius magnificus (Ogilvie-Grant)

Nycticorax magnifica Ogilvie-Grant, 1899. Ibis, p. 586: Five Finger Mountain, Hainan.

Other names: Magnificent Night-Heron in English; Martinete Magnifico in Spanish; Bihoreau superbe in French; Hainanreiher in German; Hainan yan in Chinese.

Description

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 foreneck 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.

Field characters

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.

Systematics

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. comm.). 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. comm.). 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. comm.). 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).

Habitat

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 1,300 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).

Foraging

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).

Breeding

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).

Population dynamics

With nothing known about nesting, there is also no information on population biology.

Conservation

The White-eared Night-Heron is the world’s most endangered heron; immediate action is required for its conservation. It is clearly endangered (Kushlan and Hafner 2000 IUCN 2003). Fortunately, Guangxi and Guangdong Forestry Departments and county governments are strongly committed to conserving the species (Fellowes et al. 2001). In Guangxi, the Fusui White-eared Night-Heron reserve was declared in 1999. In that only two breeding sites are known thorough surveys need to continue and expand. The recent surveys in southeast China were important first steps in identifying locations where birds remain (Fellowes et al. 2001). The surveys began by canvassing the local population, gaining public involvement, providing publicity, and following this with ground surveys. This model could be followed to great benefit in other areas where the species is expected. Where sightings occur, immediate protection of the area should be envisaged. Specific conservation issues include hunting, deforestation, reintroduction, and education. Hunting is a threat to this species, apparently even in nature reserves. Young herons are captured for the market. In fact, discovering an animal for sale in a Nanning market sparked the current conservation effort (Lee 1998). Hunting pressure of all kinds is intense in the rural agricultural areas that constitute the species’ current range. Night herons (including both this and the Malayan Night-Heron) are trapped, shot, and noosed (Fellowes et al. 2001). In Fusaui, where empty night heron nests were found, villagers have reported that they killed adult birds at the nesting site the year before (BirdLife 2001). An immediate conservation effort should be undertaken to eliminate the use of this and other rare species to meet the strong local market demand for birds. This practice threatens all the herons in the area, especially those that nest colonially. The optimal approach would be to attempt to divert hunting from all the colonial species. The night heron is a nationally protected species in China.

The principal habitat threat to the species, in fact to other Gorsachius herons as well, is habitat loss, including deforestation, reforestation with pine monoculture, reservoir construction, and gold mining. Deforestation has been underway for centuries, and the remaining diverse forests are very confined, mostly in reserves. Most of the existing forest in the area is monoculture pine plantation. This species occurs in areas of south China recognized for their importance to a collection of endemic species, many of which are now endangered. Even in reserves, degradation and disturbance continue. Tourism is increasing in remaining reserved areas, also posing threats for this heron’s well-being. Another very important threat, especially to this nocturnal species, is the numerous electric power lines concentrated usually along streams because the streams provide openings in the forest facilitating the erection of the lines. To provide habitat, truly protected forest areas are essential. At the nature reserves where the species still occurs, specific management plans are needed, including control of tourism effects, forest management and restoration, management of river bottoms and marshes as feeding habitat, realignment of reserve borders, creation of reserve corridors, and protection from hunting. When new breeding sites are found, they and the feeding habitat will require absolute protection. These qualify as Important Bird Areas for the species and need to serve as the basis of a network of reserves, managed sites and other conservation efforts aimed to protect the remaining birds. To the extent possible, a captive breeding programme should be considered. Fellowes et al. (2001) recommended that no more birds be taken from the wild. However, birds that are rescued from market could form the core of a captive population which could be used to re-establish or enhance the wild stock as sites are protected. Educational awareness of the existence and plight of the species among local populations is essential. The campaign that accompanied recent field surveys leading to the establishment of a reserve is an excellent example of meeting such needs. The species will not likely be saved except by local people.

Research needs

Clearly, with nothing known about the biology of the species, observational studies should be undertaken at every opportunity, particularly focusing on establishing the habitat requirements of the species. Surveys of known and suspected areas used by the species need to be undertaken to identify additional important areas. In order to render these surveys more efficient in the future, any opportunity should be taken to record vocalizations, for instance by captive birds. Once vocalizations are known, the periodicity of calls during the year, the day, and the night should be established in the known breeding areas. Surveys of this secretive bird in other forest habitat could then focus on the periods and hours with the highest probability of hearing a call. It is essential that the migratory status and year-round habitat needs of the species be understood. The potential feeding sites within flying distance of possible colony sites need to be determined.

Overview

The White-eared Night-Heron is the most endangered of all the herons, and biologically nearly unknown. Only a few have been seen and reported in recent years, and the world population likely numbers not many more than are presently known. This is fundamentally a lowland forest heron, which occurred in dense, wet, primary lowland forests with streams and adjacent wetlands and rice paddies. This habitat hardly exists at present. Herons that persist due so at the edge of their ecological tolerances in secondary forest in hills and mountains near residual forests. This is a species that seems to not tolerate disturbance well, and so requires reserves. Where found now it feeds in rice fields and irrigation systems. When rediscovered, the birds were in demand for the market in the area they are found, and their rarity did not provided much protection. The only hope for the species is for its welfare to become a concern of the local human population, its nesting sites be completely protected from disturbance, and feeding sites secured. The only successful conservation for this species will be that provided by and in cooperation with the local people.