Brown pelican: Difference between revisions

The '''brown pelican''' ('''''Pelecanus occidentalis''''') is a [[bird]] of the [[pelican]] family, [[Pelecanidae]], one of three [[species]] found in the Americas and one of two that feed by diving into water. It is found on the Atlantic Coast from [[New Jersey]] to the mouth of the [[Amazon River]], and along the [[Pacific coast|Pacific Coast]] from [[British Columbia]] to northern [[Chile]]Peru, including the [[Galapagos Islands]]. The [[nominate subspecies]] in its [[Glossary of bird terms#breeding plumage|breeding plumage]] has a white head with a yellowish wash on the crown. The [[nape]] and neck are dark maroon–brown. The upper sides of the neck have white lines along the base of the [[gular pouch]], and the lower fore neck has a pale yellowish patch. The male and female are similar, but the female is slightly smaller. The nonbreeding adult has a white head and neck. The pink skin around the eyes becomes dull and gray in the nonbreeding season. It lacks any red hue, and the pouch is strongly olivaceous ochre-tinged and the legs are olivaceous gray to blackish-gray.

The brown pelican was [[species description|described]] by Swedish zoologist [[Carl Linnaeus]] in the 1766 12th edition of his ''[[Systema Naturae]]'', where it was given the binomial name of ''Pelecanus occidentalis.''<ref>{{Cite book|url=https://www.biodiversitylibrary.org/item/54275#page/212/mode/1up|title=Proceedings of the United States National Museum|volume=v. 87 1941|last=Museum|first=United States National|publisher=Smithsonian Institution Press|year=1941|pages=180|language=en}}</ref> It belongs to the [[New World]] clade of the genus ''[[Pelecanus]]''.<ref name=":02">{{Cite journal|last1=Kennedy|first1=Martyn|last2=Taylor|first2=Scott A.|last3=Nádvorník|first3=Petr|last4=Spencer|first4=Hamish G.|date=2013|title=The phylogenetic relationships of the extant pelicans inferred from DNA sequence data|journal=Molecular Phylogenetics and Evolution|volume=66|issue=1|pages=215–222|doi=10.1016/j.ympev.2012.09.034|pmid=23059726|bibcode=2013MolPE..66..215K }}</ref>

Five [[subspecies]] of the brown pelican are recognized.<ref>{{Cite book|url=https://books.google.com/books?id=YrFFAAAAYAAJ|title=Grzimek's Animal Life Encyclopedia, Volume 8: Birds I|last1=Grzimek|first1=Bernhard|last2=Schlager|first2=Neil|date=2003|publisher=Gale|isbn=978-0-7876-5784-0|pages=231|language=en}}</ref><ref name="hbw2">{{cite journal|url=http://www.hbw.com/species/brown-pelican-pelecanus-occidentalis|title=Brown Pelican (''Pelecanus occidentalis'')|last1=Turner|first1=Angela|year=2020|editor1-last=Elliott|editor1-first=A.|editor2-last=Christie|editor2-first=D.A.|journal=Handbook of the Birds of the World Alive|publisher=Lynx Edicions|location=Barcelona|doi=10.2173/bow.brnpel.01 |access-date=August 18, 2017|url-access=subscription|editor3-last=Jutglar|editor3-first=F.|editor4-last=de Juana|editor4-first=E.|editor5-last=Kirwan|editor5-first=G.M.}}</ref> At least some of these subspecies are [[Genetics|genetically]] distinct despite similar [[phenotype]]s. The subspecies differ from one another in size, coloration of the throat pouch (among other bare parts) in breeding condition, and/or certain breeding plumage details, as well as geographic range.<ref>{{Cite web|title=Genetic distinctiveness of brown pelicans (Pelecanus occidentalis) from the Galápagos Islands compared to continental North America|url=https://www.researchgate.net/publication/322026100|url-status=live|website=researchgate}}</ref><ref>{{Cite web|url=https://ecos.fws.gov/docs/five_year_review/doc1039.pdf|title=Listed Distinct Population Segment of the Brown Pelican (Pelecanus occidentalis)|website=Fws.gov|access-date=17 March 2022}}</ref>

The brown pelican is part of a clade that includes the [[Peruvian pelican]] (''P. thagus'') and [[American white pelican]] (''P. erythrorhynchos''); brown and Peruvian pelicans are sister taxa, with American white pelican a more distant relative.<ref name="hbw2" /> The Peruvian pelican was previously considredconsidered a subspecies of the brown pelican, but is now considered a separate species on the basis of its much greater size (around double the weight of the brown pelican), differences in bill color and plumage, and a lack of evidence of [[Hybrid (biology)|hybridization]] between the forms where their ranges approach and overlap.<ref name=":02" /> (In captivity, the brown pelican is known to have hybridized with both the American white pelican and the more distantly related [[great white pelican]].<ref name=":3" />)

The brown pelican is the smallest of the eight extant pelican species, but is often one of the larger seabirds in their range nonetheless.<ref>{{Cite book|url=https://books.google.com/books?id=CnYMX70y1oAC&pg=PA23|title=A Field Guide to the Birds of the West Indies|last=Bond|first=James|date=1999|publisher=Houghton Mifflin Harcourt|isbn=978-0-618-00210-8|pages=23–24|language=en}}</ref><ref>Daniels, R. C., White, T. W., & Chapman, K. K. (1993). ''Sea-level rise: destruction of threatened and endangered species habitat in South Carolina''. Environmental management, 17(3), 373-385.</ref> It measures {{convert|1|to|1.52|m|ftin|0|abbr=on}} in length and has a [[wingspan]] of {{convert|2.03|to|2.28|m|ftin|0|abbr=on}}.<ref name="hbw2" /> The weight of adults can range from {{convert|2|to|5|kg|lb|abbr=on}}, about half the weight of the other pelicans found in the Americas, the Peruvian and American white pelicans. The average weight in Florida of 47 females was {{convert|3.17|kg|lb|abbr=on}}, while that of 56 males was {{convert|3.7|kg|lb|abbr=on}}.<ref name=CRC2>{{cite book |title=CRC Handbook of Avian Body Masses |edition=2nd |editor-first=John B. Jr. |editor-last=Dunning |publisher=CRC Press |year=2008 |isbn=978-1-4200-6444-5}}</ref><ref>Schreiber, R. W., Schreiber, E. A., Anderson, D. W., & Bradley, D. W. (1989). ''[https://nhm.org/site/sites/default/files/pdf/contrib_science/CS402.pdf Plumages and molts of Brown Pelicans] {{Webarchive|url=https://web.archive.org/web/20161020021046/http://www.nhm.org/site/sites/default/files/pdf/contrib_science/CS402.pdf |date=2016-10-20 }}''. Natural History Museum of Los Angeles County Contributions to Science, (402).</ref><ref>{{cite journal | last1 = Bartholomew | first1 = G. A. | last2 = Dawson | first2 = W. R. | year = 1954 | title = Temperature regulation in young pelicans, herons, and gulls | journal = Ecology | volume = 35 | issue = 4| pages = 466–472 | doi=10.2307/1931037| jstor = 1931037 | bibcode = 1954Ecol...35..466B }}</ref> Like all pelicans, it has a very long [[Beak|bill]], measuring {{convert|280|to|348|mm|in|abbr=on}} in length.<ref name="hbw2" />

The brown pelican lives on the Atlantic, Gulf, and Pacific Coasts in the Americas.<ref name=":0">{{Cite book|url=https://books.google.com/books?id=RsrV3uOZKN4C&pg=PA26|title=The Encyclopedia of Birds|last=Anonymous|date=2005|publisher=Parragon|isbn=978-1-4054-9851-7|pages=26|language=en}}</ref> On the Atlantic Coast, it is found from the [[New Jersey]] coast to the mouth of the [[Amazon River]].<ref name=":1" /> Along the [[Pacific coast|Pacific Coast]], it is found from [[British Columbia]] to south-central Chilenorthern Peru, including the [[Galapagos Islands]].<ref name=":1">{{cite report|url=https://www.fws.gov/home/feature/2009/pdf/brown_pelicanfactsheet09.pdf|title=Brown Pelican ''Pelecanus occidentalis''|date=2009|publisher=[[U.S. Fish and Wildlife Service]]|access-date=10 July 2015}}</ref><ref name="Jaramillo2009">{{cite journal|author=Jaramillo|first=A.|year=2009|title=Humboldt Current seabirding in Chile|url=https://www.researchgate.net/publication/317097666|journal=Neotropical Birding|volume=4|pages=27–39}}</ref> After nesting, North American birds [[bird migration|move]] in flocks further north along the coasts, returning to warmer waters for winter.<ref>{{Cite book|url=https://books.google.com/books?id=JhJwsTkYkoIC&pg=PT68|title=Lives of North American Birds|last=Kaufman|first=Kenn|date=2001|publisher=Houghton Mifflin Harcourt|isbn=978-0-618-15988-8|pages=40|language=en}}</ref> In the non-breeding season, it is found as far north as Canada.<ref name="iucn status 19 November 2021" /> It is a rare and irregular visitor south of [[Piura Region|Piura]] in Peru, where generally it is replaced by the Peruvian pelican, and can occur as a non-breeding visitor south at least to [[Ica Region|Ica]] during [[El Niño]] years.<ref>{{cite book|author1=Schulenberg, T.S. |author2=D.S. Stotz |author3=D.F. Lane |author4=J.P. P'Neill |author5=T.A. Parker III |year=2007 |title=Birds of Peru | publisher=Christopher Helm | pages=54–55 | isbn=978-0-7136-8673-9}}</ref> Small numbers of brown pelicans have been recorded from [[Arica]] in far northern [[Chile]].<ref name="Jaramillo2009" /> It is fairly common along the coast of California, [[South Carolina]], [[North Carolina]], [[Georgia (U.S. state)|Georgia]], the West Indies, and many Caribbean islands as far south as [[Guyana]].<ref>{{Cite book|url=https://books.google.com/books?id=HDc0AQAAMAAJ&pg=PA38|title=Port of the Americas, Municipalities of Guayanilla-Penuelas and Ponce: Environmental Impact Statement|last=Anonymous|date=2004|publisher=United States Army Corps of Engineers|pages=38|language=en}}</ref> Along the [[Gulf Coast of the United States|Gulf Coast]], it inhabits [[Alabama]], [[Texas]], [[Florida]], [[Mississippi]], [[Louisiana]], and Mexico.<ref name=":1" />

The brown pelican is a very gregarious bird; it lives in flocks of both sexes throughout the year.<ref>{{Cite book|url=https://books.google.com/books?id=ErdJAAAAYAAJ|title=The Audubon Bulletin|last=Anonymous|date=1958|publisher=Illinois Audubon Society.|pages=208–209|language=en}}</ref> In level flight, brown pelicans fly in groups, with their heads held back on their shoulders and their bills resting on their folded necks.<ref>{{Cite book|url=https://repositories.tdl.org/tamug-ir/handle/1969.3/25052|title=Minding the Coast: It's Everybody's Business : Proceedings of the Sixteenth International Conference of the Coastal Society, Addendum Volume, 12–15 July, 1998, the College of William & Mary, Williamsburg, Virginia|last=Lynch|first=Maurice P.|date=1998|publisher=Coastal Society|pages=21|language=en|access-date=2017-09-26|archive-date=2017-09-26|archive-url=https://web.archive.org/web/20170926100423/https://repositories.tdl.org/tamug-ir/handle/1969.3/25052|url-status=dead}}</ref> They may fly in a [[V formation]], but usually in regular lines or single file, often low over the water's surface.<ref>{{Cite book|url=https://books.google.com/books?id=gOYJAQAAMAAJ|title=Encyclopedia of North American Birds|last=Hall|first=Derek|date=2004|publisher=Thunder Bay Press|isbn=978-1-59223-190-4|pages=21|language=en}}</ref> To exclude water from the nasal passage, they have narrower internal regions of the nostrils.<ref>{{Cite journal|last=Richardson|first=F.|date=1939|title=Functional Aspects of the Pneumatic System of the California Brown Pelican|url=https://sora.unm.edu/sites/default/files/journals/condor/v041n01/p0013-p0017.pdf|journal=The Condor|volume=41|issue=1|pages=13–17|doi=10.2307/1364267|jstor=1364267}}</ref>

As the brown pelican flies at a maximum height of {{convert|60|to|70|ft|m|abbr=on|order=flip}} above the ocean, it can spot schools of fish while flying.<ref name=":13" /> When foraging, it dives bill-first like a [[kingfisher]],<ref>{{cite book|author=Dan A. Tallman|author2=David L. Swanson|author3=Jeffrey S. Palmer|title=Birds of South Dakota|date=2002|publisher=Northern State University Press|isbn=978-0-929918-06-8|page=11|edition=Hardcover}}</ref> often submerging completely below the surface momentarily as it snaps up prey.<ref name=":14">{{Cite book|url=https://books.google.com/books?id=1aIAAQAAQBAJ|title=The Behavior of Texas Birds|last=Rylander|first=Kent|date=2010|publisher=University of Texas Press|isbn=978-0-292-77472-8|pages=28–29|language=en}}</ref> Besides its sister species, the Peruvian pelican, this is the only pelican to primarily forage via diving, all other extant pelican merely float on the waters' surface when foraging.<ref>Arnqvist, G. (1992). ''Brown pelican foraging success related to age and height of dive''. The Condor, 94(2), 521-522.</ref><ref>Zavalaga, C. B., Dell'Omo, G., Becciu, P., & Yoda, K. (2011). ''Patterns of GPS tracks suggest nocturnal foraging by incubating Peruvian pelicans (Pelecanus thagus)''. PloS one, 6(5), e19966.</ref> Upon surfacing, it spills the water from its throat pouch before swallowing its catch.<ref name=":14" /> Only the Peruvian pelican shares this active foraging style (although that species never dives from such a great height<ref name=Jaramillo2009/>), while other pelicans forage more inactively by scooping up corralled fish while swimming on the water surface. It is an occasional target of [[kleptoparasitism]] by other fish-eating birds such as [[gull]]s, [[skua]]s, and [[frigatebird]]s.<ref>{{Cite web|url=http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-brownpelican.cfm|title=Brown pelican|website=Smithsonian's National Zoological Park|archive-url=https://web.archive.org/web/20080303181033/http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-brownpelican.cfm|archive-date=2008-03-03|access-date=2017-10-22}}</ref> They are capable of drinking saline water due to the high capacity of itstheir salt glands to excrete salt.<ref>{{Cite journal|last1=Schmidt-Nelsen|first1=K.|last2=Fange|first2=R.|date=1958|title=The function of the salt gland in the Brown Pelican|url=http://cescos.fau.edu/gawliklab/papers/Schmidt-NielsenKandRFange1958.pdf|journal=The Auk|volume=75|issue=3|pages=282–289|doi=10.2307/4081974|jstor=4081974|access-date=2017-10-23|archive-url=https://web.archive.org/web/20171023230659/http://cescos.fau.edu/gawliklab/papers/Schmidt-NielsenKandRFange1958.pdf|archive-date=2017-10-23|url-status=dead}}</ref>

Predation is occasional at colonies, and predators of eggs and young (usually small nestlings are threatened but also occasionally up to fledgling size depending on the size of the predator) can include [[gull]]s, [[Bird of prey|raptors]] (especially [[bald eagle]]s), [[Ctenosaura pectinata|spiny-tailed iguana]]s,<ref name="animaldiversity.org">{{Cite web|url=https://animaldiversity.org/accounts/Pelecanus_occidentalis/|title=Pelecanus occidentalis (brown pelican)|first=Victoria|last=Scott|website=Animaldiversity.org|access-date=17 March 2022}}</ref> [[American alligator|alligator]]s, [[vulture]]s, [[feral cat]]s, [[feral dog]]s, [[raccoon]]s,<ref name="animaldiversity.org"/> [[fish crow]]s, and [[corvid]]s.<ref name=":15">{{Cite web|url=https://www.sms.si.edu/irlspec/Peleca_occide.htm|title=''Pelecanus occidentalis''|website=www.sms.si.edu|publisher=Indian River Lagoon Species Inventory|language=en|access-date=2017-09-29|archive-date=2017-06-14|archive-url=https://web.archive.org/web/20170614044342/http://www.sms.si.edu/irlspec/Peleca_occide.htm|url-status=dead}}</ref><ref name=":6">{{Cite book|url=https://books.google.com/books?id=WjQ0AQAAMAAJ&pg=RA1-PA20|title=San Diego Harbor Deepening Project: Environmental Impact Statement|date=2003|volume=3|pages=21|language=en}}</ref><ref name=":18" /><ref>{{Cite journal|last1=Anderson|first1=Daniel W.|last2=Keith|first2=James O.|date=1980-06-01|title=The human influence on seabird nesting success: Conservation implications|journal=Biological Conservation|volume=18|issue=1|pages=65–80|doi=10.1016/0006-3207(80)90067-1|bibcode=1980BCons..18...65A }}</ref><ref>{{Cite journal|last1=Pinson|first1=D.|last2=Drummond|first2=H.|date=1993-02-01|title=Brown pelican siblicide and the prey-size hypothesis|journal=Behavioral Ecology and Sociobiology|language=en|volume=32|issue=2|pages=111–118|doi=10.1007/BF00164043|s2cid=22876247}}</ref> Predation is likely reduced if the colony is on an island. Although it is rare, [[bobcat]]s have been documented eating both the offspring and injured adults.<ref name="animaldiversity.org"/> Predation on adult brown pelicans is rarely reported, but cases where they have fallen prey to [[bald eagle]]s have been reported. Also, [[South American sea lion]]s and unidentified large [[shark]]s have been observed to prey on adult brown pelicans by seizing them from beneath while the birds are sitting on ocean waters.<ref>{{Cite journal|url=https://birdsna.org/Species-Account/bna/species/brnpel|title=Brown Pelican (''Pelecanus occidentalis''), The Birds of North America (P. G. Rodewald, Ed.)|journal=The Birds of North America Online|last=Shields|first=Mark|date=2014|language=en|doi=10.2173/bna.609|access-date=2017-09-26}}</ref><ref>{{Cite book|url=https://www.biodiversitylibrary.org/page/7766371#page/523/mode/1up|title=Habits and economic relations of the guano birds of Peru|volume=v. 56 1920|last=Coker|first=Robert Ervin|date=1919|publisher=Washington, D.C. : United States National Museum|pages=449–511|language=en|issue=56}}</ref> The invasive [[Red fire ant|red imported fire ant]]<ref>{{Cite book|url=https://books.google.com/books?id=_RRDDQAAQBAJ&pg=PA475|title=The Texas Landscape Project: Nature and People|last1=Todd|first1=David A.|last2=Ogren|first2=Jonathan|last3=Crosby|first3=Clare|date=2016|publisher=Texas A&M University Press|isbn=978-1-62349-372-1|pages=475|language=en}}</ref> is known to prey on hatchlings.<ref>{{Cite book|url=https://books.google.com/books?id=-REZ4R8wBg4C&pg=PA118|title=Common Coastal Birds of Florida and the Caribbean|last=Nellis|first=David W.|date=2001|publisher=Pineapple Press Inc|isbn=978-1-56164-191-8|pages=118|language=en}}</ref> Like all pelicans, brown pelicans are highly sensitive to disturbances by humans (including tourists or fishermen) at their nests, and may even abandon their nests.<ref name="National">[https://web.archive.org/web/20080303181033/http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-brownpelican.cfm Brown Pelican]. Smithsonian's National Zoological Park</ref> Due to their size, non-nesting adults are rarely predated.<ref name=":3" /> Brown pelicans have several parasitic worms such as ''Petagiger'', ''Echinochasmus'', ''Phagicola longus'', ''Mesostephanus appendiculatoides'', ''Contracaecum multipapillatum'', and ''Contracaecum bioccai'', from its prey diet of [[black mullet]]s, [[white mullet]]s, and other fish species.<ref name=":15" />

In the 1993 film ''[[The Pelican Brief (film)|The Pelican Brief]]'', based on the [[The Pelican Brief|novel of the same name]] by [[John Grisham]], a legal brief speculates that the assassins of two supreme court justices were motivated by a desire to drill for oil on a Louisiana marshland that was a habitat of the endangered brown pelican. In the same year, ''[[Jurassic Park (film)|Jurassic Park]]'' showed a pod of brown pelicans at the end of the film. In 1998, American conductor [[David Woodard]] performed a requiem for a California brown pelican on the seaward limit of the [[berm]] of a beach where the animal had fallen.<ref>{{cite news|last=Manzer|first=T.|url=https://juniperhills.net/p.jpg|title=Pelican's Goodbye is a Sad Song|work=[[Long Beach Press-Telegram]]|date=October 2, 1998}}</ref><ref>{{cite book|last=Allen|first=B.|title=Pelican|location=[[London]]|publisher=[[Reaktion Books]]|year=2019|url= https://books.google.com/books?id=aD96EAAAQBAJ&pg=PT152|pages=152–153|isbn=9781789141177 }}</ref>{{rp|152–153}} In the 2003 [[Disney]]/[[Pixar]] film ''[[Finding Nemo]]'', a brown pelican (voiced by [[Geoffrey Rush]] in an Australian accent) was illustrated as a friendly, virtuous talking character named Nigel.<ref>{{Cite book|url=https://books.google.com/books?id=gNEdYxQM_hkC|title=TV Guide film & video companion|last=Anonymous|date=2004|publisher=Barnes & Noble Books|isbn=978-0-7607-6104-5|pages=316|language=en}}</ref>{{efn|The film is set in Australia,<ref>{{Cite book|url=https://books.google.com/books?id=3z1i3VcYyGQC&pg=PA65|title=Film-induced Tourism|last=Beeton|first=Sue|date=2005|publisher=Channel View Publications|isbn=978-1-84541-014-8|pages=65|language=en}}</ref> although the [[Australian pelican]] is the only pelican known to occur in that country.<ref>{{Cite book|url=https://books.google.com/books?id=e0Jq2DwwDaAC|title=Wildlife of Australia|last1=Campbell|first1=Iain|last2=Woods|first2=Sam|date=2013|publisher=Princeton University Press|isbn=978-1-4008-4682-5|pages=80|language=en}}</ref>}}

Seabirds have become increasingly important as an [[Bioindicator|indicator species]]. They are often used in order to indirectly track changes in fish stocks, ecosystem health, and [[climate change]].<ref>{{Cite journal|last=Einoder|first=L. D.|date=2009-01-01|title=A review of the use of seabirds as indicators in fisheries and ecosystem management|url=http://www.sciencedirect.com/science/article/pii/S0165783608003093|journal=Fisheries Research|language=en|volume=95|issue=1|pages=6–13|doi=10.1016/j.fishres.2008.09.024|bibcode=2009FishR..95....6E |issn=0165-7836}}</ref> Environmental changes tend to have fast acting impacts on marine bird populations due to the simplicity of their [[trophic cascade]], allowing for complex, long term trends in ecosystem health and resources to be easily realized and tracked.<ref>{{Cite journal|last1=Durant|first1=Jm|last2=Hjermann|first2=Dø|last3=Frederiksen|first3=M|last4=Charrassin|first4=Jb|last5=Le Maho|first5=Y|last6=Sabarros|first6=Ps|last7=Crawford|first7=Rjm|last8=Stenseth|first8=Nc|date=2009-07-14|title=Pros and cons of using seabirds as ecological indicators|url=http://www.int-res.com/abstracts/cr/v39/n2/p115-129/|journal=Climate Research|language=en|volume=39|issue=2|pages=115–129|doi=10.3354/cr00798|bibcode=2009ClRes..39..115D|issn=0936-577X|doi-access=free|hdl=10852/37340|hdl-access=free}}</ref> Brown pelicans have proven to be a useful indicator in determining the effects of the well-established fishing industry in Southern California. Sardine fishery in the [[Gulf of California]] has been showing signs of overfishing since the early 1990s.<ref name=":22">{{Cite journal|last1=Velarde|first1=Enriqueta|last2=Ezcurra|first2=Exequiel|last3=Cisneros-Mata|first3=Miguel A.|last4=LavÍn|first4=Miguel F.|date=April 2004|title=SEABIRD ECOLOGY, EL NIÑO ANOMALIES, AND PREDICTION OF SARDINE FISHERIES IN THE GULF OF CALIFORNIA|url=http://dx.doi.org/10.1890/02-5320|journal=Ecological Applications|volume=14|issue=2|pages=607–615|doi=10.1890/02-5320|bibcode=2004EcoAp..14..607V |issn=1051-0761}}</ref> Sardine population and abundance, however, is difficult to monitor and obtain indicators for.<ref name=":22" /> Since lacking food availability has negative implications for breeding success in seabirds, seabird diet, and breeding success have been used to indirectly measure the population status of the fish they feed on.<ref name=":22" /> This model has been shown to work using brown pelicans as an indicator species. As the proportion of sardines in the brown pelican's diet decreases, the success of [[Fishery|fisheries]] declines to a lesser extent.<ref name=":20" /> When eventually the sardine abundance has declined enough for brown pelicans to move away and begin feeding on other forage fish, commercial fishing still would be fishing in significant numbers.<ref name=":20" /> This indicates that even when fisheries are not seeing signs of declining sardine abundance, brown pelicans may have already been affected to the point of locating other food sources.<ref name=":20" /> This availability of sardines may decline even further during El Niño anomalies, when [[thermocline]]s prevent brown pelicans from reaching their prey.<ref name=":20" /> Brown pelican diet will mostly indicate declines in sardine abundance for fisheries during the same season, as brown pelicans feed mostly on the same adult fish that are commercially fished.<ref name=":20" /> Although brown pelicans serve as an important indicator species for fisheries, declining sardine abundance due to both climate changes and overfishing have huge implications on overall ecosystem health, within or outside the individual trophic cascade.

== NotesExplanatory notes ==

* [https://www.flickr.com/groups/birdguide/pool/tags/Pelecanus%20occidentalis Field Guide Page] on [[Flickr]]

[[Category:PelecanusArticles containing video clips]]

[[Category:NativeBirds birdsdescribed ofin the Southeastern United States1766]]