LC
Zigzag Heron Zebrilus undulatus



Taxonomy

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.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2022 Least Concern
2016 Near Threatened A3c
2012 Near Threatened A3c
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Near Threatened
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 7,800,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals unknown not applicable not applicable 0
Population trend Decreasing suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 10-19 - - -
Decline (10 years/3 generation past and future) 10-19 - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 3.86 - - -

Population justification: The population size is not known. The species is considered to be scarce, but widespread and locally common or numerous; it may be easily overlooked (Martínez-Vilalta et al. 2020).

Trend justification: The species is suspected to be in decline as a consequence of habitat loss and local impacts of hunting. Over three generations (11.6 years), 6% of tree cover is lost within the range (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). Given that the species is strictly dependent on forests near watercourses, the rate of population decline may be larger than the rate of tree cover loss due to the impacts of habitat fragmentation and degradation; moreover, hunting may additionally aggravate the rate of population decline. Therefore, the rate of population decline is tentatively placed in the band 10-19% over three generations.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Bolivia N Extant Yes
Brazil N Extant Yes
Colombia N Extant Yes
Ecuador N Extant Yes
French Guiana N Extant Yes
Guyana N Extant Yes
Peru N Extant Yes
Suriname N Extant Yes
Venezuela N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Guyana Maparri - Kanuku Mountains
Guyana Crane Pond- Rupununi River
Colombia Lagos de Yahuarcaca e Isla Ronda

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Mangrove Vegetation Above High Tide Level suitable resident
Forest Subtropical/Tropical Swamp major resident
Wetlands (inland) Permanent Freshwater Marshes/Pools (under 8ha) major resident
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major resident
Altitude 0 - 500 m Occasional altitudinal limits (max) 800 m

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent

Recommended citation
BirdLife International (2022) Species factsheet: Zebrilus undulatus. Downloaded from http://www.birdlife.org on 06/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/12/2022.