Wikipedia

American white pelican

TheAmerican white pelican(Pelecanus erythrorhynchos) is a largeaquaticsoaring bird from theorderPelecaniformes.It breeds in interior North America, moving south and to the coasts, as far as Costa Rica, in winter.[3]

American white pelican
Flying in Dallas, USA

Apparently Secure(NatureServe)[2]
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Pelecanidae
Genus: Pelecanus
Species:
P. erythrorhynchos
Binomial name
Pelecanus erythrorhynchos
Gmelin,1789
Breeding
Migration
Year-round
Nonbreeding
Synonyms

Pelecanus erythrorhynchus(lapsus)

Taxonomy

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The American white pelican wasformally describedin 1789 by the German naturalistJohann Friedrich Gmelinin his revised and expanded edition ofCarl Linnaeus'sSystema Naturae.He placed it with the other pelicans in thegenusPelecanusand coined thebinomial namePelecanus erythrorhynchos.[4]Gmelin based his description on the "rough-billed pelican" that had been described in 1785 by the English ornithologistJohn Latham.Latham had access to three specimens that had been brought to London from New York and theHudson Bayarea of North America.[5][6]Thescientific namemeans "red-billed pelican", from theLatin termfor apelican,Pelecanus,anderythrorhynchos,derived from theAncient Greekwordserythros(ἐρυθρός,"red" ) +rhynchos(ῥύγχος,"bill" ).[7]The species ismonotypic:nosubspeciesare recognised.[8]

Description

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Adult nonbreeding inMarin County,California.Note the lack of "horn" and duller bare parts.
American white pelicans gathering atPelican Island National Wildlife RefugeinFlorida.Brown pelicans can also be seen in the center, and at the left and right margins.
With wings spread, showing black remiges

The American white pelican rivals thetrumpeter swan,with a similar overall length, as one of the longest birds native to North America. Both very large and plump, it has an overall length of about 50–70 in (130–180 cm), courtesy of the huge beak which measures 11.3–15.2 in (290–390 mm) in males and 10.3–14.2 in (260–360 mm) in females. It has a wingspan of about 95–120 in (240–300 cm).[9]The species also has the second-largest average wingspan of any North American bird, after theCalifornia condor.This large wingspan allows the bird to easily use soaring flight for migration. Body weight can range between 7.7 and 30 lb (3.5 and 13.6 kg), although typically these birds average between 11 and 20 lb (5.0 and 9.1 kg).[10]One mean body mass of 15.4 lb (7.0 kg) was reported.[10]Another study found mean weights to be somewhat lower than expected, with eleven males averaging 13.97 lb (6.34 kg) and six females averaging 10.95 lb (4.97 kg).[11]Among standard measurements, the wing chord measures 20–26.7 in (51–68 cm) and thetarsusmeasures 3.9–5.4 in (9.9–13.7 cm) long.[12]Theplumageis almost entirely bright white, except for the black primary and secondaryremiges,which are hardly visible except in flight. From early spring until after breeding has finished in mid-late summer, the breast feathers have a yellowish hue. Aftermoultinginto the eclipse plumage, the upper head often has a grey hue, as blackish feathers grow between the small wispy whitecrest.[3]

Thebillis huge and flat on the top, with a large throat sac below, and, in the breeding season, is vivid orange in color as is the bare skin around the eye and the feet.Iriscoloration depends upon age and season, ranging from bright white to hazel to blue-gray.[13]In the breeding season, both sexes grow alaterallyflattened keratinous "horn" on the upper bill, located about one-third the bill's length behind the tip. This is the only one of the eight species of pelican to have a bill "horn". The horn is shed after the birds have mated and laid their eggs. Outside the breeding season, the bare parts become duller in color, with the naked facial skin yellow and the bill, pouch, and feet a dull pink-orange.[3]

Apart from the difference in size, males and females look exactly alike. Immature birds have light grey plumage with darker brownish nape andremiges.Their bare parts are dull grey. Chicks are naked at first, then grow whitedown feathersall over, before moulting to the immature plumage.[3]

Distribution and ecology

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Non-breeding adult wintering in California

American white pelicans nest in colonies of several hundred pairs on islands in remotebrackishandfreshwaterlakes of inland North America. The most northerly nesting colony can be found on islands in the rapids of theSlave RiverbetweenFort Fitzgerald, Alberta,andFort Smith, Northwest Territories.Several groups have been visiting the bird sanctuary atUseless Bayin the state of Washington since 2015. About 10–20% of the population usesGunnison Islandin theGreat Basin'sGreat Salt Lakeas a nesting ground. The southernmost colonies are in southeasternOntarioand westernNevada.[14][15]

They winter on the Pacific andGulf of Mexicocoasts from central California andFloridasouth toCosta Rica,and along theMississippi Riverat least as far north asSt. Paul, Minnesota.In winter quarters, they are rarely found on the open seashore, preferringestuaries,bays, and lakes. They cross deserts and mountains but avoid the open ocean onmigration.[3]But stray birds, often blown off course byhurricanes,have been seen in the Caribbean. InColombianterritory, it was recorded first on February 22, 1997, on theSan Andrés Island,where they might have been swept byHurricane Marcowhich passed nearby in November 1996. Since then, there have also been a few observations likely to pertain to this species on the Colombian mainland, e.g. atCalamar.[16]

Wild American white pelicans may live for more than 16 years. In captivity, the record lifespan stands at over 34 years.[3]

Food and feeding

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American white pelicans fishing in a group near Corte Madera, California

Unlike thebrown pelican(P. occidentalis), the American white pelican does not dive for its food. Instead, it catches its prey while swimming. Each bird eats more than four pounds (1.8 kg) of food a day.[17]The fish taken by pelicans can range from the size ofminnowsto 3.5-poundpickerels.[18]Typical fish prey includeCypriniformeslikecommon carp(Cyprinus carpio), Lahontantui chub(Gila bicolor obesa),[19]minnows,[20]andshiners.[21]PerciformeslikeSacramento perch(Archoplites interruptus) oryellow perch(Perca flavescens),[21]Salmoniformeslikerainbow trout(Oncorhynchus mykiss) andsalmon,[20]Siluriformes(catfish),[22]andjackfish.[23]Other animals eaten by these birds arecrayfish,amphibians, and sometimes larval salamanders.[24]Birds nesting on saline lakes, where food is scarce, will travel great distances to better feeding grounds.[3]

American white pelicans like to come together in groups of a dozen or more birds to feed, as they can thus cooperate and corral fish to one another. When this is not easily possible – for example in deep water, where fish can escape by diving out of reach – they prefer to forage alone. But the birds also steal food on occasion from other birds, a practice known askleptoparasitism.White pelicans are known to steal fish from other pelicans,gulls,andcormorantsfrom the surface of the water and, in one case, from agreat blue heronwhile both large birds were in flight.[3][25]

Reproduction

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As noted above, they are colonial breeders, with up to 10,000 pairs per site.[26]The birds arrive on the breeding grounds in March or April; nesting starts between early April and early June. During the breeding season, both males and females develop a pronounced bump on the top of their large beaks. This conspicuous growth is shed by the end of the breeding season.

The nest is a shallow depression scraped in the ground, into which some twigs, sticks, reeds, or similar debris have been gathered. After about one week of courtship and nest-building, the female lays aclutchof usually two or three eggs, sometimes just one, sometimes up to six.

Both parentsincubatefor about one month. The young leave the nest 3–4 weeks after hatching; at this point, usually only one young per nest has survived. They spend the following month in acrecheor "pod", moulting into immature plumage and eventually learning to fly. Afterfledging,the parents care for their offspring some three more weeks, until the close family bond separates in late summer or early fall, and the birds gather in larger groups on rich feeding grounds in preparation for the migration to the winter quarters. They migrate south by September or October.[3]

  • American white pelican (breeding) in Green Bay, WI, 2013
  • Nest atChase Lake
  • Adults on their nests, already in nonbreeding plumage (note dark nape)
  • A captive American white pelican (right) alongside twogreat white pelicans(Pelecanus onocrotalus) inSt James's Park,London(note the damaged 'horn')

Predation

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Occasionally, these pelicans may nest in colonies on isolated islands, which is believed to significantly reduce the likelihood of mammalian predation.Red foxesandcoyotesprey upon colonies that they can access, and several gulls have been known to prey on pelican eggs and nestlings (includingherring,ring-billed,andCalifornia gull), as well ascommon ravens.Young pelicans may be hunted bygreat horned owls,red-tailed hawks,bald eagles,andgolden eagles.The pelicans react to mammalian threats differently from avian threats. Though fairly approachable while feeding, the pelicans may temporarily abandon their nests if a human closely approaches the colony. If the threat is another bird, however, the pelicans do not abandon the nest and may fight off the interloper by jabbing at them with their considerable bills.[27]Full-grown pelicans have few predators. Onlyred foxesandcoyotesare known to prey on nesting adults on rare occasions.[28]

Status and conservation

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This species is protected by theMigratory Bird Treaty Act of 1918.It has theCalifornia Department of Fish and Gameprotective statusCalifornia species of special concern(CSC). On a global scale, however, the species is common enough to qualify as a Species ofLeast Concernaccording to theIUCN.[1]

Habitat loss is the largest known cause of nesting failure, with flooding and drought being recurrent problems. Human-related losses include entanglement in fishing gear, boating disturbance, andpoachingas well as additional habitat degradation.[29]

There was a pronounced decline in American white pelican numbers in the mid-20th century, attributable to the excessive spraying ofDDT,endrin,and otherorganochloridesin agriculture as well as widespread draining and pollution of wetlands. But populations have recovered well after stricterenvironmental protectionlaws came into effect, and are stable or slightly increasing today. By the 1980s, more than 100,000 adult American white pelicans were estimated to exist in the wild, with 33,000 nests altogether in the 50 colonies in Canada, and 18,500 nests in the 14–17 United States colonies. Shorelineerosionat breeding colonies remains a problem in some cases, as are the occasional mass poisonings whenpesticidesare used near breeding or wintering sites.[3]

References

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  1. ^abBirdLife International (2016)."Pelecanus erythrorhynchos".IUCN Red List of Threatened Species.2016:e.T22697611A93624242.doi:10.2305/IUCN.UK.2016-3.RLTS.T22697611A93624242.en.Retrieved19 November2021.
  2. ^"Pelecanus erythrorhynchos".Natureserve Explorer.Retrieved17 April2024.
  3. ^abcdefghijElliott, Andrew (1992): 6. American White Pelican.In:del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.):Handbook of the Birds of the World(Vol. 1: Ostrich to Ducks): 310, plate 20. Lynx Edicions, Barcelona.ISBN84-87334-10-5
  4. ^Gmelin, Johann Friedrich(1789).Systema naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis(in Latin). Vol. 1, Part 2 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 571.
  5. ^Latham, John(1785).A General Synopsis of Birds.Vol. 3, Part 2. London: Printed for Leigh and Sotheby. p. 586.
  6. ^Mayr, Ernst;Cottrell, G. William, eds. (1979).Check-List of Birds of the World.Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 191.
  7. ^Jobling, James A. (2010).The Helm Dictionary of Scientific Bird Names.London: Christopher Helm. pp.295,150.ISBN978-1-4081-2501-4.
  8. ^Gill, Frank;Donsker, David;Rasmussen, Pamela,eds. (August 2022)."Ibis, spoonbills, herons, Hamerkop, Shoebill, pelicans".IOC World Bird List Version 12.2.International Ornithologists' Union.Retrieved2 December2022.
  9. ^del Hoyo, J; Elliot, A; Sargatal, J (1996).Handbook of the Birds of the World.Vol. 3. Barcelona:Lynx Edicions.ISBN84-87334-20-2.
  10. ^abCRC Handbook of Avian Body Massesby John B. Dunning Jr. (Editor). CRC Press (1992),ISBN978-0-8493-4258-5.
  11. ^CRC Handbook of Avian Body Masses, 2nd Editionby John B. Dunning Jr. (Editor). CRC Press (2008),ISBN978-1-4200-6444-5.
  12. ^Dorr, Brian S.; King, D. Tommy; Gerard, Patrick; and Spalding, Marilyn G. (2005)"The Use of Culmen Length to Determine Sex of the American White Pelican".USDA National Wildlife Research Center – Staff Publications. Paper 9.
  13. ^Kinney, Matthew E.; Ericsson, Aaron C.; Franklin, Craig L.; Whiting, Rebecca E.H.; Pearce, Jacqueline W. (2017)."OCULAR FINDINGS AND SELECT OPHTHALMIC DIAGNOSTIC TESTS IN CAPTIVE AMERICAN WHITE PELICANS (PELECANUS ERYTHRORHYNCHOS) ".Journal of Zoo and Wildlife Medicine.48(3): 675–682.doi:10.1638/2016-0256.1.ISSN1042-7260.PMC6312112.PMID28920779.
  14. ^Tymstra, Y.; Weseloh, D. V.; Moore, David; Crump, Doug; Ludwig, James (2024-06-01)."American White Pelicans expand breeding range into western Lake Erie, 2016-2018".Ontario Birds.37(1).
  15. ^Moulton, Colleen E.; Roberts, Shane B.; Horne, Jon S.; Wackenhut, Martha (2018-09-01),"Changes in abundance, productivity, and distribution of western American White Pelicans (Pelecanus erythrorhynchos), 1981–2014"(PDF),Trends and Traditions: Avifaunal Change in Western North America,Western Field Ornithologists, pp. 258–268,doi:10.21199/swb3.14,ISBN978-0-9790585-3-0,retrieved2024-11-22
  16. ^Estela, Felipe A.; Silva, John Douglas & Castillo, Luis Fernando (2005): El pelícano blanco americano (Pelecanus erythrorhynchus) en Colombia, con comentarios sobre los effectos de los huracanes en el Caribe [The American White Pelican (Pelecanus erythrorhynchus) in Colombia, with comments on the effects of Caribbean hurricanes].Caldasia27(2): 271- 275 [Spanish with English abstract].PDF fulltext
  17. ^Knopf, Fritz L. and Roger M. Evans (2004)."American white pelican - Pelecanus erythrorhynchos".U.S. Fish & Wildlife Service.
  18. ^Bent, Arthur Cleveland. Life histories of North American petrels and pelicans and their allies. Vol. 121. US Government Printing Office, 1922.
  19. ^"American White Pelican".Truckee River Guide.24 June 2023.
  20. ^ab"Pelecanus erythrorhynchos (American white pelican)".Animal Diversity Web.
  21. ^abBLAIR F. MCMAHON AND ROGER M. EVANS (1992)."NOCTURNAL FORAGING IN THE AMERICAN WHITE PELICAN'"(PDF).Searchable Ornithological Research Archive.
  22. ^Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. (2018)."American White Pelican - Pelecanus erythrorhynchos".Montana Field Guide.
  23. ^Dronen, Norman O.; Blend, Charles K. & Anderson, Christy K. (2003)."Endohelminths from the Brown Pelican, Pelecanus occidentalis, and the American White Pelican, Pelecanus erythrorhynchus, from Galveston Bay, Texas, U.S.A., and Checklist of Pelican Parasites".Comparative Parasitology.70(2): 140–154.doi:10.1654/1525-2647(2003)070[0140:EFTBPP]2.0.CO;2.S2CID85757144.
  24. ^Dan A. Tallman; David L. Swanson; Jeffrey S. Palmer (2002).Birds of South Dakota.Aberdeen, South Dakota: Midstates/Quality Quick Print. p. 10.ISBN0-929918-06-1.
  25. ^Nesbitt, S.A.; Folk, M.J. (2003)."Kleptoparasitism of great blue herons by American white pelicans".Florida Field Naturalist.31(2): 19–45. Archived fromthe originalon 2014-05-03.
  26. ^Kijowski, Ashley M.; Neill, John; Wickline, Adam; Swift, Jessica; Butler, Jaimi K.; Kimberly, David A.; Van Leeuwen, Jim; Luft, John; Stone, Kyle (2020), Baxter, Bonnie K.; Butler, Jaimi K. (eds.),"American White Pelicans of Gunnison Island, Great Salt Lake, Utah",Great Salt Lake Biology: A Terminal Lake in a Time of Change,Cham: Springer International Publishing, pp. 311–344,doi:10.1007/978-3-030-40352-2_10,ISBN978-3-030-40352-2,retrieved2024-11-22
  27. ^Dewey, Tanya.Pelecanus erythrorhynchos.Animal Diversity Web
  28. ^Knopf, F. L. and R. M. Evans (2020). American White Pelican (Pelecanus erythrorhynchos), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.https://doi.org/10.2173/bow.amwpel.01
  29. ^Blood, Donald A.; Hames, Michael; Graham, Arifin; Pawlas, Richard & Friis, Laura (1993)"American White Pelican"ArchivedFebruary 27, 2009, at theWayback MachineinWildlife in British Columbia at Risk.Province of British Columbia Ministry of Environment, Lands and Parks.ISBN0-7726-7466-3
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