Zonerodius heliosylus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Pelecaniformes Ardeidae

Scientific Name: Zonerodius heliosylus (Lesson, 1828)
Common Name(s):
English Forest Bittern
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2017
Date Assessed: 2017-10-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A.
Contributor(s): Beehler, B., Bishop, P., Burrows, I., Burrows, R., Gibbs, D., Mack, A. & Dutson, G.
Facilitator/Compiler(s): Benstead, P., Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Pilgrim, J., Wheatley, H.
This species qualifies as Near Threatened because it has a moderately small population which is thought to be undergoing a slow to moderate decline owing to habitat degradation. Further evidence to suggest that the rate of decline may be slower than previously assessed may mean that this species warrants downlisting in the future.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Zonerodius heliosylus occurs throughout New Guinea (Papua, formerly Irian Jaya, Indonesia and Papua New Guinea) and on the adjacent islands of Salawati and Aru, Indonesia. There are few recent records but it appears to be widespread from the lowlands to 1,650 m (Sam and Koane 2014, Beehler and Pratt 2016).
Countries occurrence:
Indonesia; Papua New Guinea
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:1270000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):100
Upper elevation limit (metres):1650
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Fewer than 10,000 individuals are estimated to survive (unpublished information supplied by Wetlands International Specialist Groups), so it is placed in the band 2,500-9,999 individuals here. This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend Justification:  The population is suspected to be slowly declining owing to ongoing habitat destruction. Across the mainland coastal provinces of Papua New Guinea, 1.3% forest was lost plus 2.5% was logged between 2002 and 2014 (Bryan and Shearman 2015). Although the species' tolerance of logged forest is not known, all records appear to have been from old-growth forest, and its rate of population decline is assessed as 1-9% in three generations (22 years).
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:1500-7000Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:It frequents streams, pools and swamps in forest to 1,650 m (Sam and Koane 2014) and forages on the edges of forest creeks and pools on fish, reptiles, crustaceans and insects (Pratt and Beehler 2015, Sam and Koane 2014). Bulky nests are built in forest midstory (Pratt and Beehler 2015).

Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):7.4
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): Although it is not hunted (B. M. Beehler in litt. 1994) and there are still huge areas of suitable habitat left, it may be threatened by the extensive logging of lowland forest (I. Burrows in litt. 1994, R. Burrows in litt. 1994), especially as it occurs along watercourses (A. Mack in litt. 1999).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
None is known.

Conservation Actions Proposed
Survey to better understand the abundance and distribution of the species. Protect large areas of lowland rainforest. Ensure protection of forests along watercourses.

Citation: BirdLife International. 2017. Zonerodius heliosylus. The IUCN Red List of Threatened Species 2017: e.T22697274A117210228. . Downloaded on 18 June 2018.
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