Larus delawarensis

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 delawarensis

Species Authority:

Ord, 1815

Common Name/s:

English	–	Ring-billed Gull
French	–	Goéland à bec cerclé

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 an extremely 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 extremely 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:	The Ring-billed Gull breeds in the USA and Canada from in north California, east Washington and interior British Columbia, across the praire provinces, north mountains and plain states. Also from the Great Lakes east to the coast. It winters in the southern portion of its breeding range south to the Gulf Coast, Mexico, Central America, Greater and Lesser Antilles (del Hoyo et al. 1996).
Countries:	Native: Anguilla; Antigua and Barbuda; Aruba; Bahamas; Barbados; Belize; Bermuda; Bonaire, Sint Eustatius and Saba; Brazil; Canada; Cayman Islands; Colombia; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Ecuador; El Salvador; Guadeloupe; Guatemala; Haiti; Honduras; Martinique; Mexico; Montserrat; Panama; Puerto Rico; Saint Kitts and Nevis; Saint Lucia; Saint Pierre and Miquelon; Saint Vincent and the Grenadines; Sint Maarten (Dutch part); Trinidad and Tobago; Turks and Caicos Islands; United States; Venezuela; Virgin Islands, British; Virgin Islands, U.S. Vagrant: Austria; Belgium; Bulgaria; Denmark; Faroe Islands; France; Germany; Gibraltar; Greenland; Hungary; Iceland; Ireland; Jamaica; Kiribati; Morocco; Netherlands; Norway; Poland; Portugal; Senegal; South Africa; Spain; Svalbard and Jan Mayen; Sweden; Switzerland; United Kingdom Present - origin uncertain: Saint Martin (French part)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population Trend:	Increasing

Population Trend:

Increasing

Habitat and Ecology [top]

Habitat and Ecology:	This species inhabites coasts, rivers, estuaries, reservoirs and rubbish dumps. It is a highly opportunistic feeder, owing to its varied diet including fish, insects, earthworms, refuse, offal, fiddler crabs, dates, fish eggs, grain, rodents and birds. It lays from late April to May, though this can be delayed in the north of its range due to snow cover. Colonies are often very large and found on low-lying islands in freshwater lakes, on wet meadows and rarely on rivers. Its large, bulky nests are usually built beside rocks, driftwood or vegetation (del Hoyo et al. 1996).
Systems:	Terrestrial; Freshwater; Marine

Habitat and Ecology:

This species inhabites coasts, rivers, estuaries, reservoirs and rubbish dumps. It is a highly opportunistic feeder, owing to its varied diet including fish, insects, earthworms, refuse, offal, fiddler crabs, dates, fish eggs, grain, rodents and birds. It lays from late April to May, though this can be delayed in the north of its range due to snow cover. Colonies are often very large and found on low-lying islands in freshwater lakes, on wet meadows and rarely on rivers. Its large, bulky nests are usually built beside rocks, driftwood or vegetation (del Hoyo et al. 1996).

Systems:

Terrestrial; Freshwater; Marine

Citation:	BirdLife International 2012. Larus delawarensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 23 May 2013.
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