Data Zone
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.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | - | - |
| Year | Category | Criteria |
|---|---|---|
| 2017 | Near Threatened | C1 |
| 2016 | Near Threatened | A2c+3c+4c; C1 |
| 2012 | Near Threatened | A2c+3c+4c;C1 |
| 2008 | Near Threatened | A2c; A3c; A4c; C1 |
| 2006 | Near Threatened | |
| 2004 | Near Threatened | |
| 2000 | Lower Risk/Near Threatened | |
| 1994 | Lower Risk/Near Threatened | |
| 1988 | Lower Risk/Least Concern |
| Migratory status | not a migrant | Forest dependency | high |
| Land-mass type |
shelf island |
Average mass | - |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence (breeding/resident) | 1,270,000 km2 | medium |
| Severely fragmented? | no | - |
| Estimate | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| Population size | 1500-7000 mature individuals | medium | estimated | 2005 |
| Population trend | decreasing | poor | suspected | 1998-2008 |
| Rate of change over the past 10 years/3 generations (longer of the two periods) | 1-9% | - | - | - |
| Rate of change over the future 10 years/3 generations (longer of the two periods) | 1-9% | - | - | - |
| Rate of change over the past & future 10 years/3 generations (longer of the two periods) | 1-9% | - | - | - |
| Generation length | 7.4 years | - | - | - |
Population justification: Fewer than 10,000 individuals are estimated to survive (unpublished information supplied by Wetlands International Specialist Groups), so it is placed in the band 2,500-9,999 individuals here.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).
| Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
|---|---|---|---|---|---|---|
| Indonesia | extant | native | yes | |||
| Papua New Guinea | extant | native | yes |
| Country/Territory | IBA Name |
|---|
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Forest | Subtropical/Tropical Moist Lowland | major | resident |
| Wetlands (inland) | Permanent Freshwater Marshes/Pools (under 8ha) | major | resident |
| Wetlands (inland) | Permanent Rivers/Streams/Creeks (includes waterfalls) | major | resident |
| Altitude | 100 - 1650 m | Occasional altitudinal limits |
| Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Biological resource use | Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
|
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Recommended citation
BirdLife International (2024) Species factsheet: Forest Bittern Zonerodius heliosylus. Downloaded from
https://datazone.birdlife.org/species/factsheet/forest-bittern-zonerodius-heliosylus on 24/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 24/12/2024.