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Forest Bittern Zonerodius heliosylus

Justification
This species qualifies as Near Threatened because it has a moderately small population which is thought to be undergoing a moderate decline owing to habitat degradation.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Distribution and population
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 very few recent records and it is such a reclusive species that it is impossible to assess its true population (Coates 1985, Beehler et al. 1986, K. D. Bishop in litt. 1994, D. Gibbs in litt. 1994, Eastwood 1998).

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Fewer than 10,000 individuals are estimated to survive (unpublished information supplied by Wetlands International Specialist Groups), so it is placed in the band 2,500-9,999 individuals here.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
There are no data on population trends; however, the species is suspected to be declining slowly, owing to habitat loss and degradation.

Ecology
It frequents streams, pools and swamps in forest to 1,430 m.

Threats
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 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.

References
Beehler, B. M.; Pratt, T. K.; Zimmerman, D. A. 1986. Birds of New Guinea. Princeton University Press, Princeton.

Coates, B. J. 1985. The birds of Papua New Guinea, 1: non-passerines. Dove, Alderley, Australia.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Eastwood, C. 1998. Birding on the Elevala River, Western Province, PNG. Australian Birding: 11-12.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Species factsheet from HeronConservation - The IUCN-SSC Heron Specialist Group

Text account compilers
Benstead, P., Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Pilgrim, J.

Contributors
Beehler, B., Bishop, P., Burrows, I., Burrows, R., Gibbs, D., Mack, A.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Zonerodius heliosylus. Downloaded from http://www.birdlife.org on 27/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/12/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Near Threatened
Family Ardeidae (Herons)
Species name author (Lesson, 1828)
Population size 1500-7000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 652,000 km2
Country endemic? No
Links to further information
- Additional Information on this species