Editing Rynchops (section)

==Description==
The three species are the only birds with distinctive uneven [[beak|bills]], where the [[lower mandible]] is longer than the [[upper mandible|upper]].{{cn|date=January 2023}} This remarkable adaptation allows them to fish in a unique way, flying low and fast over streams.<ref>{{cite journal | last1=Mariano-Jelicich | first1=Rocío | last2=Favero | first2=Marco | last3=Silva | first3=María | title=Fish Prey Of The Black Skimmer ''Rynchops Niger'' At Mar Chiquita, Buenos Aires Province, Argentina | journal=Marine Ornithology | volume=31 | issue=2 | date=2003 | issn=1018-3337 | doi=10.5038/2074-1235.31.2.581 | url=http://www.marineornithology.org/PDF/31_2/31_2_199-202.pdf }}</ref> Their lower mandible skims or slices over the water's surface, ready to snap shut any small fish unable to dart clear. The skimmers are sometimes included within the gull family Laridae but separated in other treatments which consider them as a sister group of the [[tern]]s.<ref>{{cite journal| title= Multilocus perspectives on the monophyly and phylogeny of the order Charadriiformes (Aves)|author1=Fain MG |author2=Peter Houde |name-list-style=amp |journal = BMC Evolutionary Biology |year= 2007 |volume=7|issue=1 | page=35 |doi= 10.1186/1471-2148-7-35|pmid=17346347| pmc= 1838420 |doi-access=free|bibcode=2007BMCEE...7...35F }}</ref> The black skimmer has an additional adaptation and is the only species of bird known to have slit-shaped [[pupils]].<ref>{{cite journal | last1=Zusi | first1=Richard L. | last2=Bridge | first2=David | title=On the Slit Pupil of the Black Skimmer (Rynchops niger) | journal=Journal of Field Ornithology | publisher=[Association of Field Ornithologists, Wiley] | volume=52 | issue=4 | year=1981 | issn=0273-8570 | jstor=27639259 | pages=338–340 | url=http://sora.unm.edu/sites/default/files/journals/jfo/v052n04/p0338-p0340.pdf}}</ref> the forehead, ends of the secondaries, tail feathers and under parts are white, the rest of the plumage is black and the basal half of the bill is crimson.<ref>{{cite book| last=Reed | first=Chester A. | title=The Bird Book: Illustrating in natural colors more than seven hundred North American birds; also several hundred photographs of their nests and eggs. | via=Project Gutenberg | year=1914 | chapter-url=https://www.gutenberg.org/cache/epub/30000/pg30000-images.html#Page_58 |page=58 |chapter=SKIMMERS. Family RYNCHOPIDÆ}}</ref> Their bills fall within their field of binocular vision, which enables them to carefully position their bill and capture prey.<ref>{{cite journal |year=2007 |title=Vision and the foraging technique of Skimmers (Rynchopidae)|journal=Ibis |volume=149|pages=750–757| last1=Martin | first1=Graham R. | last2=Mcneil | first2=Raymond | last3=Rojas | first3=Luz Marina |doi=10.1111/j.1474-919X.2007.00706.x |issue=4}}</ref> They are agile in flight and gather in large flocks along rivers and coastal sand banks.<ref>{{cite magazine |last=Fusco |first=P.J. |url=http://www.ct.gov/dep/lib/dep/wildlife/pdf_files/outreach/connecticut_wildlife_magazine/cwmj06.pdf |magazine=Connecticut Wildlife |archive-url=https://web.archive.org/web/20090914073214/http://ct.gov/dep/lib/dep/wildlife/pdf_files/outreach/connecticut_wildlife_magazine/cwmj06.pdf |archive-date=2009-09-14 |publisher=Connecticut Department of Environment Protection Bureau of Natural Resources – Wildlife Division |date=May–June 2006 |accessdate=2009-06-29 |page=10 |title=Spectacular and Intriguing - The Black Skimmer}}</ref>

They are tropical and subtropical species which lay 3–6 eggs on sandy beaches. The female incubates the eggs. Because of the species' restricted nesting habitat the three species are vulnerable to disturbance at their nesting sites. One species, the [[Indian skimmer]], is considered [[Endangered species|endangered]] by the [[IUCN]] due to this as well as destruction and degradation of the lakes and rivers it uses for feeding.<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Rynchops albicollis'' |volume=2020 |page=e.T22694268A178970109 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22694268A178970109.en |access-date=20 May 2025}}</ref>