Editing Gull (section)

==Distribution and habitat==
{{See also|List of Charadriiformes by population}}
[[File:Swallow-tailed-gull.jpg|thumb|[[Swallow-tailed gull]]s are endemic to the Galapagos Islands.]]
Gulls have a worldwide [[cosmopolitan distribution]]. They breed on every continent, including the margins of [[Antarctica]], and are even found in the high [[Arctic]]. They are less common in the [[tropics]], although a few species do live on tropical islands such as the [[Galapagos]] and [[New Caledonia]]. Many species breed in coastal colonies, with a preference for islands; one particular species, the [[grey gull]], breeds in the interior of dry deserts far from water. Considerable variety exists in the [[Laridae]] family, and species may breed and feed in marine, freshwater, or terrestrial habitats.<ref name = "HBW"/>

Most gull species are [[Bird migration|migratory]], with birds moving to warmer habitats during the winter, but the extent to which they migrate varies by species. Some migrate long distances, notably [[Sabine's gull]], which migrates from the Arctic coasts to wintering grounds off the west coasts of South America and southern Africa, and [[Franklin's gull]], which migrates from Canada to winter off the west coast of South America. Other species move much shorter distances and may simply disperse along the coasts near their breeding sites.<ref name = "HBW"/>
[[File:Haugesund komm.svg|thumb|upright=0.6|Gulls in the coat of arms of [[Haugesund]]]]
A big influence on non-breeding gull distribution is the availability of food patches. Human [[fisheries]] especially have an impact, since they often provide an abundant and predictable food resource.<ref name = "Ramírez_2015">{{cite journal|vauthors=Ramírez F, Gutiérrez-Expósito C, Afán I, Giménez J, de Stephanis R, Forero MG|date=2015-05-07|title=Human influence on gull non-breeding distribution: potential consequences of changes in fishing practices|url=http://www.int-res.com/abstracts/meps/v527/p221-232/|journal=Marine Ecology Progress Series|language=en|volume=527|pages=221–232|doi=10.3354/meps11282|bibcode=2015MEPS..527..221R|hdl=10261/122438|issn=0171-8630|doi-access=free|access-date=1 March 2021|archive-date=6 May 2021|archive-url=https://web.archive.org/web/20210506174240/http://www.int-res.com/abstracts/meps/v527/p221-232/|url-status=live|hdl-access=free}}</ref> Two species of gulls dependent on human fisheries are [[Audouin's gull]] (''Ichthyaetus audouinii'') and [[lesser black-backed gull]]s (''Larus fuscus)''; their breeding distributions (especially the black-backed gull) are heavily impacted by human fishing discards and [[fishing port]]s.<ref name = "Ramírez_2015" />

Other environmental drivers that structure bird habitat and distribution are human activity and climate impacts. For example, waterbird distribution in [[Mediterranean]] [[wetland]]s is influenced by changes in [[salinity]], water depth, water body isolation and [[wikt:hydroperiod|hydroperiod]], all of which have been observed to affect the bird community structure in both a species- and [[Guild (ecology)|guild]]-specific way.<ref name="How will climate change affect enda">{{cite journal | vauthors = Ramírez F, Rodríguez C, Seoane J, Figuerola J, Bustamante J | title = How will climate change affect endangered Mediterranean waterbirds? | journal = PLOS ONE | volume = 13 | issue = 2 | pages = e0192702 | date = 2018-02-13 | pmid = 29438428 | pmc = 5811028 | doi = 10.1371/journal.pone.0192702 | bibcode = 2018PLoSO..1392702R | veditors = Yue BS | doi-access = free }}</ref> Gulls in particular have high associations with salinity levels, which were found to be the main environmental predictor for waterbird assemblage.<ref name="How will climate change affect enda"/>