Justification This species has a very small, declining population, and therefore qualifies as Endangered. Declines are primarily a result of deforestation in its breeding and wintering ranges.

Family/Sub-family Ardeidae

Species name author (Temminck, 1835)

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Identification 49 cm. Small, stocky heron with stout bill. Rufous-brown head and neck. Black streaks down foreneck and breast. Chestnut-brown upperparts and wing-coverts with fine black vermiculations. Juvenile has blackish crown, less rufous on head, more streaked neck and paler wing-coverts. Similar spp. Malayan Night-heron G. melanolophus has black cap and long crest.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,000-2,499

decreasing

35,800 km²

No

Range & population Gorsachius goisagi breeds in Japan, and there has been one report of breeding from Taiwan (China). It has been recorded in spring and summer in Russia (Primorye and Sakhalin) and South Korea, and is a passage migrant in coastal mainland China and Hong Kong (China), and also in Taiwan. The main wintering area appears to be in the Philippines, but it has also been recorded as a non-breeding visitor to Indonesia, and as a vagrant to Brunei and Palau. It was apparently locally common in Japan until the 1970s, but by the 1980s and 1990s, had disappeared from many of its former breeding sites. There has apparently been just one recent record from mainland China, of two sightings at Wuyuan in Jiangxi Province in April 2006³. This relative paucity of recent records indicates that the population is now probably less than 1,000 mature individuals.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It breeds in heavily forested areas, including coniferous, broadleaved and degraded forest, on hills and on the lower slopes of mountains (up to 1,500 m), where there are watercourses and damp areas. It winters in dark, deeply shaded forest near water up to 2,400 m. It forages mainly in forest, but will use swamps, rice-fields and farmland and is mainly crepuscular. Breeding has been recorded from April to July¹. Earthworms are probably the principal food source, but land snails, crabs, ground and scarabid beetles are all present in its diet^2,4.

Threats The main threat is deforestation in both its breeding and non-breeding ranges. The development of dense scrub undergrowth in forest and on abandoned farmland (following a change in traditional agricultural practices) is believed to reduce the suitability of these habitats for feeding. It has probably been hunted in many parts of its range. It declined rapidly on Miyake-jima in the Izu Islands, where it was formerly abundant, following the introduction of Siberian weasel Mustela sibirica in the early 1970s. Today nest predation by Corvids is an increasing threat as crow populations increase in urban and suburban areas.

Conservation measures underway It is legally protected in Japan and Hong Kong. Birds may occur in protected areas in Japan and it has been recorded in Quezon National Park, Philippines. Environmental Impact Assessments are conducted prior to major developments in Japan, and if this species is identified using a site mitigation measures are taken⁴

Conservation measures proposed Survey its breeding range in Japan and its wintering range in the Philippines. Establish a monitoring programme of its breeding and wintering populations. Study its home-range requirements using radio-telemetry. Protect and manage forests in its breeding and wintering grounds. Ensure official protection throughout its range and strengthen and enforce legislation to prevent the sale of this (and other threatened) species. Establish public-awareness programmes concerned with its conservation. Control and monitor invasive species where appropriate within its range.

References Birdlife International (2001). 1. Kawana (2006). 2. Kawakami et al. (2005). 3. He Fen-Qi in litt. (2007). 4. K. Kawakami in litt. (2007).

Further web sources of information

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Simba Chan (Wild Bird Society of Japan), Mike Crosby (BirdLife International), Nic Peet (BirdLife International)

Contributors Fen-Qi He (Zoological Museum of China), Kazuto Kawakami (Forestry and Forest Products Research Institute), Yukihiro Kominami (Wild Bird Society of Japan)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Mike Crosby (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Gorsachius goisagi. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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