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Olrog's Gull Larus atlanticus

IUCN Red List Criteria

Near Threatened (criteria nearly met) B2b(iii) 

IUCN Red List history

Year Category
2013 Near Threatened
2012 Vulnerable
2008 Vulnerable
2006 Vulnerable
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened

Species attributes

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

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals 9800-15600 good Estimated 2007
Population trend Stable poor -
Number of subpopulations 1 - - -
Largest subpopulation - - -
Generation length (yrs) 11 - - -
Population justification: The breeding population is variable between years, with the total number of nests estimated at 4,860 pairs in 2004, 7,790 pairs in 2007 and 5,240 in 2009 (Yorio et al. in press), roughly equating to 15,600 mature individuals. The largest colony recorded is Isla del Puerto, with between 1,635 and 3,800 nests depending on the year (Petracci et al. 2008, Yorio et al. in press).
Trend justification: The apparent population increase most likely reflects a more comprehensive simultaneous survey, and the variability between years in the observed total nesting population is over 20%, indicating the uncertainty involved and showing the difficulty in defining trends. Nevertheless, despite growing pressures at key breeding sites there is no current evidence that the population is declining.

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage Resident
Argentina Native Extant Yes      
Brazil Native Extant   Yes    
Chile Unknown Extant        
Uruguay Native Extant   Yes    

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Argentina Bahía de Samborombón y Punta Rasa site factsheet
Argentina Cuenca del Río Salado site factsheet
Argentina Estuario del Río Gallegos site factsheet
Argentina Laguna Melincué site factsheet
Argentina Norte del Golfo San Jorge site factsheet
Argentina Parque Costero del Sur site factsheet
Argentina Península y Bahía de San Julián site factsheet
Argentina Playa Punta Mogotes y Puerto de Mar del Plata site factsheet
Argentina Reserva Campos del Tuyú, Estancia El Palenque y Los Ingleses site factsheet
Argentina Reserva de Biosfera Albufera de Mar Chiquita site factsheet
Argentina Reserva de Uso Múltiple Bañados del Río Dulce y Laguna Mar Chiquita site factsheet
Argentina Reserva de Uso Múltiple de Bahía Blanca, Bahía Falsa y Bahía Verde site factsheet
Argentina Reserva de Uso Múltiple San Blas y Refugio de Vida silvestre Complementario site factsheet
Argentina Reserva Natural de Uso Múltiple Isla Martín García site factsheet
Argentina Reserva Natural Punta Lara site factsheet
Argentina San Antonio Oeste site factsheet
Argentina Villa marítima El Cóndor site factsheet
Brazil Estuário da Laguna dos Patos site factsheet
Brazil Parque Nacional da Lagoa do Peixe site factsheet
Uruguay Arroyo Maldonado wetlands site factsheet
Uruguay José Ignacio Lagoon site factsheet
Uruguay Penino Beach and Santa Lucía Wetlands site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes major non-breeding
Marine Intertidal Mud Flats and Salt Flats major breeding
Marine Intertidal Mud Flats and Salt Flats major non-breeding
Marine Intertidal Rocky Shoreline suitable breeding
Marine Intertidal Rocky Shoreline suitable non-breeding
Marine Intertidal Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major breeding
Marine Intertidal Shingle and/or Pebble Shoreline and/or Beaches suitable breeding
Marine Intertidal Shingle and/or Pebble Shoreline and/or Beaches suitable non-breeding
Marine Intertidal Tidepools suitable breeding
Marine Intertidal Tidepools suitable non-breeding
Marine Neritic Macroalgal/Kelp major breeding
Marine Neritic Macroalgal/Kelp major non-breeding
Marine Neritic Pelagic marginal resident
Marine Neritic Seagrass (Submerged) major breeding
Marine Neritic Seagrass (Submerged) major non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs major breeding
Marine Neritic Subtidal Rock and Rocky Reefs major non-breeding
Marine Neritic Subtidal Sandy major breeding
Marine Neritic Subtidal Sandy major non-breeding
Marine Neritic Subtidal Sandy-Mud major breeding
Marine Neritic Subtidal Sandy-Mud major non-breeding
Altitude 0 - 0 m Occasional altitudinal limits  

Threats & impact

Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Livestock farming & ranching / Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Fishing & harvesting aquatic resources / Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Decline Medium Impact: 6
Stresses
Indirect ecosystem effects
Biological resource use Hunting & trapping terrestrial animals / Intentional use (species is the target) Timing Scope Severity Impact
Past, Likely to Return Majority (50-90%) Slow, Significant Decline Past Impact
Stresses
Species mortality
Pollution Industrial & military effluents / Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Whole (>90%) Slow, Significant Decline Medium Impact: 7
Stresses
Ecosystem degradation
Residential & commercial development Commercial & industrial areas Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Decline Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Residential & commercial development Tourism & recreation areas Timing Scope Severity Impact
Future Majority (50-90%) Slow, Significant Decline Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion

Utilisation

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

Recommended citation
BirdLife International (2014) Species factsheet: Larus atlanticus. Downloaded from http://www.birdlife.org on 21/10/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/10/2014.

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 Laridae (Gulls, Terns, Skimmers)
Species name author Olrog, 1958
Population size 9800-15600 mature individuals
Population trend Stable
Distribution size (breeding/resident) -
Country endemic? No
Links to further information
- Summary information on this species