Ecology Summary - Larus occidentalis

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Ecology of Larus occidentalis

Main Ref.	SAUP Database, 2006
Remarks	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).

Main Ref.

SAUP Database, 2006

Remarks

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).

Aquatic zones / Water bodies

	Marine - Neritic	Marine - Oceanic	Brackishwater	Freshwater
Marine zones / Brackish and freshwater bodies	supra-littoral zone littoral zone sublittoral zone	epipelagic mesopelagic epipelagic abyssopelagic hadopelagic	estuaries/lagoons/brackish seas mangroves marshes/swamps	rivers/streams lakes/ponds caves exclusively in caves

Highighted items on the list are where Larus occidentalis may be found.

Habitat

Substrate
Substrate Ref.
Special habitats
Special habitats Ref.

Associations

Ref.
Associations
Associated with
Association remarks
Parasitism

feeding

Feeding type
Feeding type Ref.
Feeding habit
Feeding habit Ref.

Trophic Level(s)

Estimation method	original sample		unfished population		Remark
Estimation method	Troph	s.e.	Troph	s.e.	Remark
From diet composition
From individual food items	4.28	0.66			Trophic level estimated from a number of food items using a randomized resampling routine.
Ref.

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