Larus glaucescens

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	CHARADRIIFORMES	LARIDAE

Scientific Name:

Larus glaucescens

Species Authority:

Naumann, 1840

Common Name/s:

English

–

Glaucous-winged Gull

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Symes, A.

Contributor/s:

Justification:
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 appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not 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.

History:

2009	–	Least Concern
2008	–	Least Concern
2004	–	Least Concern

Geographic Range [top]

Range Description:	This species ranges from northern Mexico in the Gulf of California and on the western coast of Baja California, up the Pacific coast of North America to Alaska, across the Aleutian Islands (USA) to the northern coast of Japan. Its breeding range begins on the coast of Washington (USA), through Canada and Alaska to the Commander Islands (Russia) (del Hoyo et al. 1996)
Countries:	Native: Canada; Japan; Mexico; Russian Federation; United States Vagrant: China; Hong Kong; Morocco; Spain
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The global population is estimated to number > c.570,000 individuals (Wetlands International 2006), while the population in Russia has been estimated at c.100-10,000 breeding pairs and c.50-1,000 individuals on migration (Brazil 2009).
Population Trend:	Increasing

Habitat and Ecology [top]

Habitat and Ecology:	This species can be found in coastal areas and over shelf waters. Its diet is comprised of fish, various marrine invertebrates, carrion, offal, bird eggs and small mammals, with the exact composition varying depending on locality. It uses a variety of feeding methods, including plunge-diving, diving from the surface and dropping shellfish on rocks. It arrives at breeding colonies between February and March, and will nest on a wide variety of substrates including rocky islands, cliffs, inland lakes, city parks and buildings. It is usually colonial but can be solitary. Some birds remain on their territories over winter, but others will migrate to the southern edges of its range (del Hoyo et al. 1996).
Systems:	Terrestrial; Freshwater; Marine

Habitat and Ecology:

This species can be found in coastal areas and over shelf waters. Its diet is comprised of fish, various marrine invertebrates, carrion, offal, bird eggs and small mammals, with the exact composition varying depending on locality. It uses a variety of feeding methods, including plunge-diving, diving from the surface and dropping shellfish on rocks. It arrives at breeding colonies between February and March, and will nest on a wide variety of substrates including rocky islands, cliffs, inland lakes, city parks and buildings. It is usually colonial but can be solitary. Some birds remain on their territories over winter, but others will migrate to the southern edges of its range (del Hoyo et al. 1996).

Systems:

Terrestrial; Freshwater; Marine

Citation:	BirdLife International 2012. Larus glaucescens. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 21 May 2013.
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