CR
Brazilian Merganser Mergus octosetaceus



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
C2a(i) C2a(i); D C2a(i); D1

Red List history
Year Category Criteria
2019 Critically Endangered C2a(i)
2016 Critically Endangered C2a(i)
2015 Critically Endangered C2a(i)
2013 Critically Endangered C2a(i)
2012 Critically Endangered C2a(i)
2010 Critically Endangered C2a(i)
2009 Critically Endangered C2a(i)
2008 Critically Endangered
2006 Critically Endangered
2004 Critically Endangered
2000 Critically Endangered
1996 Critically Endangered
1994 Critically Endangered
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency Does not normally occur in forest
Land mass type Land-mass type - continent
Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 1,380,000 medium
Number of locations 8 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 50-249 medium estimated 1994
Population trend Decreasing poor inferred -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations 6 - - -
Percentage in largest subpopulation 1-89 - - -
Generation length (yrs) 6.5 - - -

Population justification: The population was estimated at 250 individuals in 1992, and was thought likely to have declined since, given ongoing threats. However, there are recent suggestions that the population may exceed this figure (L.V. Lins in litt. 2012). Recent estimates from the three main areas currently known to hold the species are of 70-100 territories (140-200 mature individuals) in the Serra da Canastra area (L.V. Lins in litt. 2012, 2013), fewer than 50 individuals at Chapada dos Veadeiros (Disconzi 2012) and eight at Jalapão (IECOS Brasil 2013 per L.V. Lins in litt. 2013, Barbosa et al. 2015), but these figures require confirmation. The population is currently precautionarily maintained within the band 50-249 mature individuals.

Trend justification: This species's population is suspected to have declined rapidly over the last 20 years (three generations), in line with habitat loss and degradation within its range, owing to the expansion of hydroelectric power schemes, soy bean cultivation and mining operations. It appears to have been extirpated from Paraguay.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Argentina N Extant Yes
Brazil N Extant Yes
Paraguay N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Argentina Parque Provincial Urugua-í
Argentina Cuenca del Piray Miní
Brazil Parque Nacional da Chapada dos Veadeiros e Adjacências
Brazil Jalapão
Brazil Serra da Canastra
Brazil Rio Arrojado

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major resident
Altitude 0 - 1100 m Occasional altitudinal limits  

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 Majority (50-90%) Rapid Declines Medium Impact: 7
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
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation
Energy production & mining Mining & quarrying Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Species disturbance
Natural system modifications Dams & water management/use - Dams (size unknown) Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Pollution Agricultural & forestry effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Sport hunting/specimen collecting - - Non-trivial Recent

Recommended citation
BirdLife International (2021) Species factsheet: Mergus octosetaceus. Downloaded from http://www.birdlife.org on 22/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2021.