View source for Biology:Yellow-footed gull

{{Short description|Species of bird}}
{{Speciesbox
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=BirdLife International |date=2020 |title=''Larus livens'' |volume=2020 |page=e.T22694340A168885266 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22694340A168885266.en |access-date=13 November 2021}}</ref>
| image =Larus livens 2910976.jpg
| genus = Larus
| species = livens
| authority = Dwight, 1919
| range_map = Larus livens map.svg
| range_map_caption = Distribution {{leftlegend|#87aade|Non-Breeding}}{{leftlegend|#8d5fd3|Year-round}}
}}

The '''yellow-footed gull''' ('''''Larus livens''''') is a large [[Biology:Gull|gull]], closely related to the [[Biology:Western gull|western gull]] and thought to be a subspecies until the 1960s. It is endemic to the Gulf of California.

==Description==
Adults are similar in appearance to the western gull with a white head, dark, slate-colored back and wings, and a thick yellow bill.  Its legs are yellow, though first winter birds do display pink legs like those of the western gull. It attains full plumage at three years of age.

This species is tied with [[Biology:Slaty-backed gull|slaty-backed gull]] for the world's fourth-largest gull species and is one of the largest gulls in the world, being slightly larger than the western gull. It measures {{convert|53|to|72|cm|in|abbr=on}} in length and spans {{convert|140|to|160|cm|in|abbr=on}} across the wings.<ref name= "Olsen">''Gulls: Of North America, Europe, and Asia'' by Klaus Malling Olsen & Hans Larsson. Princeton University Press (2004). {{ISBN|978-0691119977}}.</ref> The body mass of this species can vary from {{convert|930|to|1500|g|lb|abbr=on}}.<ref name= "Olsen"/><ref name = "CRC">''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), {{ISBN|978-0-8493-4258-5}}.</ref> Among standard measurements, the [[Biology:Wing chord|wing chord]] is {{convert|40|to|46|cm|in|abbr=on}}, the bill is {{convert|5.0|to|6.2|cm|in|abbr=on}} and the [[Biology:Tarsus (skeleton)|tarsus]] is {{convert|5.9|to|7.5|cm|in|abbr=on}}.<ref name= "Olsen"/>

==Distribution and habitat==
Yellow-footed gulls are native to the Gulf of California in Mexico.  Most are non-[[Biology:Bird migration|migratory]], but an increasing number have been traveling to {{wipe|California}}'s [[Engineering:Salton Sea|Salton Sea]] and southwards to [[Place:Sonora|Sonora]] during nonbreeding periods. Their breeding habitat is the Gulf of California, where they nest, in April, either independently or in colonies. They are found on sandy and rocky coasts or islands, often with little vegetation.<ref name=BLI>{{cite web |url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=3224 |title=Species factsheet: ''Larus livens''|publisher=BirdLife International |access-date=2013-12-13}}</ref>

==Behavior==
The birds are [[Earth:Scavenger|scavenger]]s as well as foragers, feeding on small [[Biology:Fish|fish]] and [[Biology:Invertebrate|invertebrate]]s, carcases of marine mammals and offal, and preying upon seabird chicks and eggs (including pelican eggs).<ref name=BLI/> They sometimes scavenge around waste dumps and docks for refuse but seldom fly far inland.<ref name=PoB>{{cite web |url=http://www.planetofbirds.com/charadriiformes-laridae-yellow-footed-gull-larus-livens |title=Yellow-footed Gull (''Larus livens'') |date=2011-07-08 |publisher=Planet of Birds |access-date=2013-12-13}}</ref>

Yellow-footed gulls nest on the beach, a few metres above the upper limits of the highest tides. A pair of birds defends a small [[Biology:Territory (animal)|territory]] between the nest and the sea. The nest is a scrape in the sand with a meagre lining of seaweed or dry plant material. Usually, three eggs are laid, olive or buff in color with dark blotches, and [[Biology:Egg incubation|incubation]] is probably done by both parents. The young are fully [[Biology:Fledge|fledge]]d and leave the nest when they are about seven weeks old.<ref name=PoB/>

==Status==
The population is estimated at about 60,000 individuals and appears to be stable, so the IUCN has rated the species as being of "least concern".<ref name=BLI/>

==References==
{{Reflist}}
* "National Geographic"  ''Field Guide to the Birds of North'' ''America'' {{ISBN|0-7922-6877-6}}
* ''Seabirds, an Identification Guide'' by Peter Harrison, (1983) {{ISBN|0-7470-1410-8}}
* ''Handbook of the Birds of the World Vol 3'',  Josep del Hoyo editor, {{ISBN|84-87334-10-5}}
* "National Audubon Society" ''The Sibley Guide to Birds'', by David Allen Sibley, {{ISBN|0-679-45122-6}}

==External links==
*[http://audubon2.org/webapp/watchlist/viewSpecies.jsp?id=227 Audubon: Yellow-footed Gull]
*[http://www.slostateparks.com/nature/birds/yellow_footed_gull.asp Yellow-footed Gull (Larus livens)] {{Webarchive|url=https://web.archive.org/web/20051109030722/http://www.slostateparks.com/nature/birds/yellow_footed_gull.asp |date=2005-11-09 }}


{{Taxonbar|from=Q629447}}

[[Category:Larus|yellow-footed gull]]

{{Sourceattribution|Yellow-footed gull}}