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Brazilian Merganser Mergus octosetaceus

IUCN Red List Criteria

Critically Endangered C2a(i) 
Endangered A2ce+3ce+4ce; C1+2a(i); D1 
Vulnerable C2a(i); D 

IUCN Red List history

Year Category
2013 Critically Endangered
2012 Critically Endangered
2010 Critically Endangered
2009 Critically Endangered
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 continent
Average mass -

Distribution

  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 51,300 medium
Number of locations 8 -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals 50-249 medium Estimated 1994
Population trend Decreasing poor -
Number of subpopulations 6 - - -
Largest subpopulation 1-50 - - -
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), but these figures require confirmation and 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 Breeding Non-breeding Passage Resident
Argentina Native Extant       Yes
Brazil Native Extant       Yes
Paraguay Native Extant       Yes

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Argentina Cuenca del Piray Miní site factsheet
Argentina Parque Provincial Urugua-í site factsheet
Brazil Jalapão site factsheet
Brazil Parque Nacional da Chapada dos Veadeiros e Adjacências site factsheet
Brazil Rio Arrojado site factsheet
Brazil Serra da Canastra site factsheet

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 Decline 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 Decline Medium Impact: 6
Stresses
Ecosystem degradation
Energy production & mining Mining & quarrying Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Decline 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 Decline Low Impact: 5
Stresses
Ecosystem degradation

Utilisation

Purpose Primary form used Life stage used Source Scale Level Timing
Sport Whole Adults and juveniles Wild Subsistence, National Non-trivial Recent

Recommended citation
BirdLife International (2014) Species factsheet: Mergus octosetaceus. Downloaded from http://www.birdlife.org on 25/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/12/2014.

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 Critically Endangered
Family Anatidae (Ducks, Geese, Swans)
Species name author Vieillot, 1817
Population size 50-249 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 51,300 km2
Country endemic? No
Links to further information
- Summary information on this species