Larus occidentalis Audubon, 1839
Western gull
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Family:  Laridae ()
Max. size:  68 cm TL (male/unsexed); max.weight: 1,010.0 g
Environment:  others; marine
Distribution:  Eastern Pacific and Western Atlantic. Subtropical to temperate.
Diagnosis:  Culmen: 5.56 cm; tarsus: 7.197 cm; wing: 41.2 cm.
Biology:  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 NiƱo) events; severe events in 1982-1983 causing adult mortality. (Ref. 87784).
IUCN Red List Status: (LC); Date assessed: 08 August 2018 Ref. 123251)
Threat to humans: 
Country info:   
 

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