Creagrus furcatus


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Creagrus furcatus
Species Authority: (Néboux, 1842)
Common Name(s):
English Swallow-tailed Gull

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Ekstrom, J., Butchart, S., Calvert, R.
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Geographic Range [top]

Range Description: The Swallow-tailed Gull breeds mainly on the Galapagos Islands, Ecuador (all major and several minor islands) but also on Malpelo Island, Colombia. When not breeding it can be found along the Pacific coast of South American from Ecuador to northern Chile1.
Chile; Colombia; Costa Rica; Ecuador; Peru
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species feeds mostly at night but also by day, heavily exploiting squid at night but also taking clupeid fish. It appears to suffer from periodic food shortages, and is often observed feeding 500 km from the nearest land. It breeds throughout the year and asynchronously across the Galapagos, with individual subcolonials being synchronised by social interactions. It forms loose colonies with large inter-nest distances but can be solitary, nesting on steep slopes or broken cliffs, often on broad clifftop ledges but also just above the wave line, and on gravelly beaches and under vegetation. Adults leave the colony after breeding and become highly pelagic, returning in 4-5 months often to their previous nest site.
Systems: Terrestrial; Marine

Citation: BirdLife International 2012. Creagrus furcatus. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 03 September 2015.
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