Podilymbus gigas 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Podicipediformes Podicipedidae

Scientific Name: Podilymbus gigas
Species Authority: Griscom, 1929
Common Name(s):
English Atitlan Grebe, Giant Grebe, Giant Pied-billed Grebe, Atitlán Grebe
Spanish Poc de Atitlán, Somormujo de Atitlán, Zambullidor de Atitlán, Zampullín del Atitlán
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. Lynx Edicions BirdLife International.
Taxonomic Notes: The taxon has been considered a large and flight-impaired subspecies of Pied-billed Grebe Podilymbus podiceps (Livezey 1989a, Howell and Webb 1995). Hybridisation between the two taxa may have been a factor in the final extinction of P. gigas (Hunter 1988).

Assessment Information [top]

Red List Category & Criteria: Extinct ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A. & Butchart, S.
Facilitator/Compiler(s): Brooks, T., Khwaja, N., Mahood, S.
This species was endemic to Lake Atitlán, Guatemala, but is now Extinct. Its extinction occurred sometime between 1983 and 1986, caused by myriad alterations to its habitat.
Previously published Red List assessments:
2008 Extinct (EX)
2004 Extinct (EX)
2000 Extinct (EX)
1996 Extinct (EX)
1994 Extinct (EX)
1988 Threatened (T)

Geographic Range [top]

Range Description: Podilymbus gigas was endemic to Lake Atitlán, Guatemala (LaBastille 1974). Its population dropped from c.200 to 80 in the 1960s, but recovered to a high of 232 in 1975 (LaBastille 1984). However, various factors drove the population down to 30 by 1983, and it was extinct by 1986 (LaBastille 1990).

Countries occurrence:
Regionally extinct:
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Lower elevation limit (metres): 1500
Upper elevation limit (metres): 1500
Range Map: Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology: It inhabited one freshwater lake.

Systems: Freshwater
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 5.4
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): Initial population declines were a result of competition and predation by large-mouth bass Micropterus salmoides, introduced into the lake in 1960 (LaBastille 1984). However, increasing pressure on breeding sites from local reed-cutting and from tourism development, along with the murder of the government game warden for the national park during the political unrest of 1982 and falling lake levels following the earthquake of 1976, are likely to be the factors which drove the population to extinction (LaBastille 1990). Drowning in gill nets and disturbance by increasing boat traffic have also been suggested as contributory factors (Collar et al. 1994).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Still listed on Appendix I of CITES.

Citation: BirdLife International. 2012. Podilymbus gigas. The IUCN Red List of Threatened Species 2012: e.T22696577A38947132. . Downloaded on 30 November 2015.
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