Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Larus fuliginosus
Species Authority: Gould, 1841
Common Name(s):
English Lava Gull
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:

Identification information: 53 cm. Unmistakable, all-dark gull. Overall dark ashy-grey, darkest on wings and palest on belly and vent. Noticeably darker hood with white eyelids. Black bare parts, red inside of mouth. Immature browner.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D1 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Cruz, F., Vargas, H. & Wiedenfeld, D.
Facilitator/Compiler(s): Benstead, P., McClellan, R., Pilgrim, J., Sharpe, C J, Symes, A.
This poorly known species is considered Vulnerable because it has a very small population. Numbers are assumed to be stable, although there are a number of potential threats, which may be having an impact.

Previously published Red List assessments:
2010 Vulnerable (VU)
2008 Vulnerable (VU)
2006 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Near Threatened (NT)

Geographic Range [top]

Range Description: Larus fuliginosus breeds only in the Galápagos Islands, Ecuador. It is widespread throughout the archipelago, with possibly the most dense populations found at Puerto Ayora (Santa Cruz) (Jackson 1985, H. Vargas and F. Cruz in litt. 2000), Puerto Baquerizo Moreno (San Cristóbal) and Puerto Villamil (Isabela) (H. Vargas and F. Cruz in litt. 2000). In 1963, a survey of 56 km of coastline on the south and east of Santa Cruz found eight territories, which was extrapolated over the remaining coastline in the archipelago to give an estimate of 300-400 pairs. This has been considered an overestimate, and an estimate by Aguirre (2007) determined only 81 individuals in the largest population, on Santa Cruz Island. If extrapolated, this would produce a total population of only 243 individuals (D. Wiedenfeld in litt. 2012). It has been suggested that the tiny population is probably a consequence of its confinement to linear feeding grounds of restricted range, which provide a limited food supply for much of the year (Snow and Snow 1969).

Countries occurrence:
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 1480
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 11-100
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Snow and Snow (1969) estimated 600-800 mature individuals which Wetlands International (2002) interpreted to equate to 900-1,200 individuals. This may be an overestimate (Aguirre 2007, D. Wiedenfeld in litt. 2012).

Trend Justification:  Numbers are assumed to be stable although there are a number of potential threats which may be having an impact

Current Population Trend: Increasing
Additional data:
Number of mature individuals: 600-800 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 2-100 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No
No. of individuals in largest subpopulation: 1-89

Habitat and Ecology [top]

Habitat and Ecology: It nests solitarily in sheltered places near lagoons, pools and other calm water, usually close to the sea (Snow and Snow 1969). It is a scavenger, with local concentrations of birds in areas of high food availability, such as harbours, and will associate with boats (Burger and Gochfeld 1996). However, it also takes seabird eggs, juvenile marine iguana Amblyrhynchus cristatus, small fish and crustaceans (Snow and Snow 1969). It nests in scrapes on sandy beaches or low outcrops close to water, and lays two eggs (Burger and Gochfeld 1996). Territories are large (Snow and Snow 1969).

Systems: Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 6
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): Lava Gulls are threatened by fishing activities, such as being caught on hooks as bycatch and direct persecution by fishermen, and from feeding on refuse (Wiedenfeld and Jiménez 2008). Potential threats (applicable to many of the Galápagos seabirds) include predation and disturbance by introduced mammals such as feral cats, rats and dogs (Cepeda and Cruz 1994, H. Vargas and F. Cruz in litt. 2000).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Although much of the island archipelago is protected in the Galápagos National Park, the greatest densities of this species may occur in the three main ports  (Wiedenfeld 2006), and these urban areas are not part of the national park (H. Vargas and F. Cruz in litt. 2000). The islands were declared a World Heritage Site in 1979.

Conservation Actions Proposed
Develop and use methodologies for accurate population censuses and long-term monitoring (H. Vargas and F. Cruz in litt. 2000). Identify nesting areas and control populations of introduced mammals.

Citation: BirdLife International. 2012. Larus fuliginosus. The IUCN Red List of Threatened Species 2012: e.T22694452A37873659. . Downloaded on 09 October 2015.
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