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Larus occidentalis   Audubon, 1839

western gull
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Larus occidentalis
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Classification / Names Common names | Synonyms | CoL | ITIS | WoRMS

Aves | Ciconiiformes | Laridae

Environment: milieu / climate zone / depth range / distribution range Ecology

Others.  Temperate

Distribution Countries | FAO areas | Ecosystems | Occurrences | Introductions

Eastern Pacific and Western Atlantic. Subtropical to temperate.

Length at first maturity / Size / Weight / Age

Maturity: Lm ?  range ? - ? cm Max length : 68.0 cm TL male/unsexed; (Ref. 8812); max. published weight: 1.0 kg (Ref. 356)

Short description Morphology

Culmen: 5.56 cm; tarsus: 7.197 cm; wing: 41.2 cm.

Biology     Glossary (e.g. epibenthic)

Total Length: 61 to 68 cm; Wingspan: 132 to 142 cm (Ref. 8812). Occupies the continental shelf; <80 km (Ref. 356). Scavengers; exhibits kleptoparasitism (Ref. 356). Opportunistic feeders that eat a wide variety of food. Based on stable isotope analysis (SIA) diet study of egg albumin, belongs to lower N signature group (based on ratios of stable isotopes of nitrogen and carbon) indicating a more planktivorous diet. Switch in diet from garbage to fish when chicks hatch for its higher nutritional content to assure higher fledging success. Early breeding and early egg-laying assures higher fledging success for this species. On the Farallon Islands, California, high nest failures recorded during ENSO (El Niño) events; severe events in 1982-1983 causing adult mortality. (Ref. 87784).

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Main reference References | Coordinator | Collaborators

Schreiber, R.W. 1970. (Ref. 80153)

IUCN Red List Status (Ref. 115185)

CITES status (Ref. 108899)

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

Human uses

| FishSource |

More information

Common names
Egg development
Mass conversion

Internet sources

BHL | BOLD Systems | CISTI | DiscoverLife | FAO(Publication : search) | GenBank (genome, nucleotide) | GloBI | | Google Books | Google Scholar | Google | ispecies | PubMed | Tree of Life | Wikipedia (Go, Search) | Zoological Record

Estimates of some properties based on models

Preferred temperature (Ref. 115969): 5.4 - 18.5, mean 8.3 (based on 112 cells).
Vulnerability (Ref. 71543)
Moderate to high vulnerability (47 of 100)
Price category (Ref. 80766)