{"elementGlobalId":102273,"circumscripConfidence":{"id":1,"circumscripConfidenceDescEn":"1 - Strong","circumscripConfidenceDescEs":"1 - Fuerte","circumscripConfidenceDescFr":"1 – Forte"},"classificationLevel":{"id":7,"classificationLevelNameEn":"Species","classificationLevelNameEs":"Especies","classificationLevelNameFr":"Espèce"},"classificationStatus":{"id":1,"classificationStatusDescEn":"Standard","classificationStatusDescEs":"Estándar","classificationStatusDescFr":"Standard"},"iucn":{"id":11,"iucnDescEn":"Least concern","iucnDescEs":"Menos preocupante","iucnDescFr":"Moins préoccupante","iucnCode":"LC"},"nameCategory":{"id":1,"nameCategoryDescEn":"Vertebrate Animal","nameCategoryDescEs":"Animal vertebrado","nameCategoryDescFr":"Animal vertébré","nameTypeCd":"A","nameTypeDesc":"Zoological"},"rankMethodUsed":null,"formattedScientificName":"<i>Gelochelidon nilotica</i>","scientificName":"Gelochelidon nilotica","scientificNameAuthor":"(Gmelin, 1789)","primaryCommonName":"Gull-billed Tern","relatedItisNames":"<i>Sterna nilotica</i> J. F. Gmelin, 1789 (TSN 176926)","uniqueId":"ELEMENT_GLOBAL.2.102273","elcode":"ABNNM08010","conceptRefFullCitation":"American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.","conceptName":"<i>Sterna nilotica</i>","taxonomicComments":"Formerly (AOU 1983, 1998) included in the genus <i>Sterna </i>but separated on the basis of genetic data that correspond to plumage patterns (Bridge et al. 2005) (AOU 2006).","roundedGRank":"G5","conservationStatusFactorsEditionDate":"2007-09-17","conservationStatusFactorsEditionAuthors":"Via, J., D. C. Duffy, G. Hammerson, M. Koenen, and D. W. Mehlman","primaryCommonNameLanguage":"EN","recordType":"SPECIES","elementNationals":[{"elementNationalId":165764,"classifConfidence":null,"nation":{"id":225,"nameEn":"United States","nameEs":"Estados Unidos","nameFr":"États-Unis","isoCode":"US","region":"United States"},"roundedNRank":"N4B,N4N","elementSubnationals":[{"elementSubnationalId":348485,"subnation":{"id":34,"nameEn":"North Carolina","nameEs":"Carolina del Norte","nameFr":"Caroline du 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Jersey","nameEs":"Nueva Jersey","nameFr":"New 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York","subnationCode":"NY","dnationId":225},"roundedSRank":"S1","dataSensitive":{"id":2,"dataSensitiveDescEn":"No","dataSensitiveDescEs":null,"dataSensitiveDescFr":null,"dataSensitiveCode":"N"},"dataSensitiveCategory":null,"srank":"S1","speciesSubnational":{"elementSubnationalId":360848,"hybrid":false,"exotic":false,"native":true}},{"elementSubnationalId":331644,"subnation":{"id":11,"nameEn":"Delaware","nameEs":"Delaware","nameFr":"Delaware","subnationCode":"DE","dnationId":225},"roundedSRank":"SHB,S1N","dataSensitive":{"id":2,"dataSensitiveDescEn":"No","dataSensitiveDescEs":null,"dataSensitiveDescFr":null,"dataSensitiveCode":"N"},"dataSensitiveCategory":null,"srank":"SHB,S1N","speciesSubnational":{"elementSubnationalId":331644,"hybrid":false,"exotic":false,"native":true}}],"nrankReviewYear":1997,"nrank":"N4B,N4N","speciesNational":{"elementNationalId":165764,"exotic":false,"native":true}}],"lastModified":"2026-10-02T21:38:31.532814Z","lastPublished":"2026-10-02T21:32:08.892226Z","promotionalDescription":null,"conceptLineageSummary":null,"nsxUrl":"/Taxon/ELEMENT_GLOBAL.2.102273/Gelochelidon_nilotica","grankAdjustmentReasons":null,"grankChangeDate":"1996-11-27","grankReviewDate":"2007-09-17","grankReasons":null,"grank":"G5","rankInfo":{"elementGlobalId":102273,"aooPercentGood":null,"enviromentalSpecificity":null,"intrinsicVulnerability":null,"longTermTrend":{"id":46,"longTermTrendDescEn":"Unknown","longTermTrendDescEs":"Desconocido","longTermTrendDescFr":"Inconnu"},"numberEos":{"id":14,"numberEosDescEn":"81 to >300","numberEosDescEs":"De 81 a >300","numberEosDescFr":"De 81 à >300"},"numberGoodEos":null,"numberProtEos":{"id":14,"numberProtEosDescEn":"Many to very many (13 to >40) occurrences appropriately protected and managed","numberProtEosDescEs":"De varios a muchos casos (13 a >40) adecuadamente protegidos y controlados","numberProtEosDescFr":"De plusieurs à beaucoup d’occurrences (de 13 à >40) protégées et contrôlées convenablement"},"popSize":{"id":34,"popSizeDescEn":"100,000 - 1,000,000 individuals","popSizeDescEs":"De 100.000 a 1.000.000 de individuos","popSizeDescFr":"De 100 000 à 1 000 000 individus"},"rangeExtent":{"id":35,"rangeExtentDescEn":">2,500,000 square km (greater than 1,000,000 square miles)","rangeExtentDescEs":">2.500.000 kilómetros cuadrados (más ","rangeExtentDescFr":">2 500 000 km carrés (plus de 1 000 000 miles carrés)"},"shortTermTrend":{"id":37,"shortTermTrendDescEn":"Decline of <30% to relatively stable","shortTermTrendDescEs":"Disminución de <30% a relativamente estable","shortTermTrendDescFr":"Diminution de <30 % à relativement stable"},"threatImpactAssigned":{"id":8,"threatImpactAssignedDescEn":"Medium","threatImpactAssignedDescEs":"Medio","threatImpactAssignedDescFr":"Moyen"},"rangeExtentComments":"Breeding range includes southern California (San Diego Bay, Salton Sea), western coast of Mexico (Sonora, Sinaloa, Baja California, Gulf of California), Atlantic and Gulf coasts of North America from New York (Long Island; scarce north of Maryland) south to Florida and west to southern Texas (also inland); and probably also in Tamaulipas and Veracruz in eastern Mexico, the Bahamas, and Virgin Islands (Anegada, probably Sombrero, formerly Cockroach Bay); in South America (southwestern Ecuador, and from central Brazil south to northern Argentina); and in the Old World from northern Europe, central Russia, southern Mongolia, and eastern China south to northwestern Africa,Asia Minor, Iran, India, Sri Lanka, and southern China; and in Australia (Sprunt 1954, Parnell et al. 1995, AOU 1998). <br><br>Nonbreeding range in the Americas includes coastal areas from Nayarit, the Gulf Coast, and southern Florida south through Middle America and the West Indies to Peru and northern Argentina (AOU 1998). In the Old World, the nonbreeding range extends from tropical Africa, Persian Gulf, India, Southeast Asia, eastern China, and the Philippines south to southern Africa, Java, and Borneo; also Australia and Tasmania (AOU 1998).","areaOfOccupancy":null,"areaOfOccupancyComments":null,"numberEosComments":"This species is represented by a large number of breeding occurrences (subpopulations).","popSizeComments":"Global population was estimated at 79,000-310,000 in 2002 (Wetlands International). National Audubon Society waterbird conservation website (http://web1.audubon.org/waterbirds) reported the global population at 195,000. The European population is fewer than 22,000 pairs (BirdLife International 2004).<br><br>The current U.S. population of the eastern subspecies <i>aranea </i>(which breeds along the Atlantic and Gulf of Mexico coasts of the United States and northeastern Mexico) is unlikely to exceed 3,600 pairs, with over 60% of these birds occurring in Texas (Molina and Erwin 2006). As few as 250 pairs of subspecies <i>vanrossemi  </i>nest at only two locations in the United States, both in California (Molina and Erwin 2006). Including populations in western Mexico, the entire <i>vanrossemi </i>population totals 600-800 pairs (Molina and Erwin 2006).","viabilityComments":null,"threatImpactComments":"This species was historically decimated by egg collectors and plume hunters. Via and Duffy (1992) concluded that loss of upland foraging sites and island nesting sites has probably been the greatest threat, although predation and competition with gulls, and human disturbance at colonies have also contributed to declines. Other threats include beach erosion and development.<br><br>Main threats to populations in North America include loss of natural nesting islands through beach erosion or perturbations to estuarine functions, development or modification of upland habitats near breeding areas that may be important for foraging, and disturbances to colonies by humans and feral or human-subsidized predators (Molina and Erwin 2006).<br><br>HABITAT LOSS: Destruction of marshes and nesting sites has probably been the most important problem in the past for gull-billed terns and other waterbirds (Erwin 1980). The past effects of marsh ditching on nesting and foraging are unknown, as are the historical population levels before market hunting and marsh drainage. Today, however, most northeastern marshes are either publicly owned or subject to laws that, at least in theory, protect them from further damage.<br><br>ENVIRONMENTAL CONTAMINATION: At the mouths of major estuaries, terns may be exposed to a wide variety of water-borne contaminants, including crude oil and other petroleum products. Analyses of eggs from South Carolina, however, indicated that levels of hydrocarbons were insufficient to induce eggshell thinning and reproductive failure (Blus and Stafford 1980).<br><br>HUMAN DISTURBANCE: Human disturbance may include a wide variety of human activities ranging from walking near nesting colonies to more severe forms of disturbance, such as vehicular traffic and slaughter of waterbirds (Parnell et al. 1988). Disturbance may result in desertion of nesting areas or exposure of eggs and chicks to extreme temperatures, rain, wind, and numerous predators, particularly gulls. Human disturbance has its most disastrous effects following hatching, because chicks may leave the nest prematurely and suffer excessive mortality (Sears 1978). Erwin (1980) compared barrier island nest sites in New Jersey with those in Virginia and found that the New Jersey sites were less frequently used by terns because of human disturbance.  While there are no guidelines for the minimum distance at which gull-billed terns will flush, Erwin (1989) has proposed a minimum distance of 200 m for posting colonies of black skimmers and common terns, species with which gull-billed terns often nest. However, because these birds are extremely sensitive to disturbance during the nesting period (Sears 1978), even these distances may be insufficient.<br><br>PREDATION/COMPETITION: Both pet and feral dogs may pose a problem. Potential mammalian predators include raccoons, red foxes, and rats (<i>Rattus </i>spp.). Suspected rat predation on the eggs and nests was reported in two studies (Sears 1978, Blus and Stafford 1980). Nocturnal avian predators of common terns that are also likely to prey on gull-billed terns include great horned owls and black-crowned night-herons (Nisbet 1975, Morris and Wiggins 1986). Potential diurnal avian predators in the northeast include, laughing gulls, herring gulls, and great black-backed gulls (Buckley and Buckley 1972). Blus and Stafford (1980) suggested that predation by laughing gulls caused nearly complete nesting failure from 1972-75 in South Carolina. Other avian predators include the fish crow and northern harrier. During a period of population decline in Virginia (1975-90), there was an almost a ten-fold increase in the numbers of herring and great black-backed gulls, species which may usurp nesting sites or prey on gull-billed terns (Williams et al., in press). Nesting common terns have abandoned the barrier islands for a more protected, human-made island in the Chesapeake Bay (Williams et al., in press) and this may have left the remaining gull-billed terns at greater risk from predation.","shortTermTrendComments":"Overall, the current global rate of decline probably is less than 30 percent over 10 years or three generations. Trends are difficult to determine because the species tends to nest in small, scattered, and often ephemeral colonies (Molina and Erwin 2006).","longTermTrendComments":"GLOBAL: No global trends are apparent although local increases and decreases have been noted for different subpopulations (Moller 1975, Cramp 1985).<br><br>EUROPE: Declines were noted through the 1900s in northwestern Europe (Evans 1984). A moderate decline occurred in Europe between 1970 and 1990 (BirdLife International 2004). Although the species was broadly stable in southwestern Europe and Russia during 1990-2000, it declined in southeastern Europe and continued to decline overall (BirdLife International 2004).<br><br>NORTH AMERICA: Kress et al. (1983) noted a declining U.S. population. Buckley and Buckley (1984) suggested that the eastern population was declining. In Virginia, the population declined 88% between 1975 and 1988 (Byrd and Johnston 1991). Gulf Coast population is concentrated in southern Texas and was estimated at 4,250 in 1982; at that time it may have been increasing (Spendelow and Patton 1988). Populations in the southeastern United States were relatively stable in the 1980s (Clapp and Buckley 1984).<br><br>More recent analyses indicate that the breeding range of the species has contracted and shifted slightly from the known historical range in the middle Atlantic states (Molina and Erwin 2006). The Texas population has remained generally stable, but population declines have occurred in Maryland (where probably extirpated), Virginia, North Carolina, Florida, and possibly Georgia (Molina and Erwin 2006). In eastern Mexico, historical information is almost nonexistent, and knowledge of current distribution and abundance is incomplete (Molina and Erwin 2006), so trend is uncertain.<br><br>Population changes in the northeastern part of the North American range are probably responses to changes in populations farther south. Expanding populations or breeding ranges in northern states might reflect \"overflow\" birds from increasing southern populations (Buckley and Buckley 1984). Similarly, decreases in the northern population might reflect reduction in numbers at southern colonies, as well as other factors such as destruction of northern breeding habitats or increased mortality of wintering birds. Distinguishing among these and other possible causes of decline is difficult and probably requires long-term data on breeding and wintering numbers throughout the range. Counts from single colonies or even single regions may be impossible to interpret in isolation.<br><br>Nesting range expanded north from Mexico to California beginning in the 1920s, but the Salton Sea population has declined significantly since then. Some range contraction may have occurred in western Mexico (e.g., in Sonora) (Molina and Erwin 2006).<br><br>","inventoryNeeds":null,"numberProtEosComments":"On a global scale, probably there are many adequately protected occurrences.","protectionNeeds":null,"otherConsiderations":null,"intrinsicVulnerabilityComments":null,"enviromentalSpecificityComments":null},"animalCharacteristics":{"elementGlobalId":102273,"majorHabitat":{"id":3,"majorHabitatDescEn":"Terrestrial","majorHabitatDescEs":"Terrestre","majorHabitatDescFr":"Terrestre"},"nonMigrant":true,"localMigrant":true,"longDistanceMigrant":true,"mobilityMigrationComments":"North American birds migrate as far south as Peru and the Guianas (Hilty and Brown 1986). Migration along the coast of Costa Rica occurs September-early November (mainly Pacific coast) and April-May (both coasts) (Stiles and Skutch 1989). Arrives in eastern U.S. breeding areas usually in mid-April, adults depart usually in late July and early August (Erwin 1979).","foodHabitsComments":"Eats mainly various insects, also other invertebrates, and small vertebrates, including eggs and young of other birds; forages mostly over and in fields and marshes, occasionally picks prey from water surface, rarely dives into water. Foraging normally takes place within 10 km of the colony (Sears 1976). Unlike other terns, rarely feeds over open water (Ashmole 1971); instead forages by flying low over marshes, open fields, shrubs, and agricultural fields, with a gull-like flight. Upon locating food, stall briefly, then drop to the ground, vegetation, or substrate to capture prey (Cramp 1985). Their feeding behavior is similar to that of the laughing gull (LARUS ATRICILLA) with which they are frequently observed feeding over agricultural fields (Meanley 1981). <br><br>Gull-billed terns sometimes forage over quiet estuaries and ponds, where they pick fish and invertebrates from the surface. Unlike other species of terns, they rarely dive. They sometimes feed with black skimmers on small fish concentrated in drying marsh pools (J. Via, pers. obs.). They rarely feed in conspecific groups because many of their invertebrate prey tend to be dispersed rather than aggregated like the fish schools exploited by other species of terns (Erwin 1978). <br><br>Major dietary items include arthropods, locusts, grasshoppers, dragonflies, insects, spiders, and marine life such as fiddler crabs, crustacea, crabs, and sand bugs (Wilson 1840, Bent 1921, Sprunt 1954, Rohwer and Woolfenden 1968, Cramp 1985, Quinn and Wiggins 1990). Vertebrate fauna consumed by the gull-billed tern include fish, frogs, toads, lizards, small mammals (Bent 1921, Dement'ev et al. 1951, Bannerman 1962), green anoles (ANOLIS CAROLINENSIS) (Rohwer and Woolfenden 1968), and mice (Hobbs 1976). <br><br>These birds are occasional opportunistic predators on the downy chicks of other beach-nesting birds including gull-billed (Zubakin 1975) and least terns (Densmore 1990), and possibly piping plovers (CHARADRIUS MELODUS) (R. Cross, pers. comm.).","animalPhenologyComments":null,"colonialBreeder":true,"length":36,"width":null,"weight":170,"animalPhenologies":[{"animalCagPhenologyId":101775,"animalPhenology":{"id":3,"animalPhenologyDescEn":"Diurnal","animalPhenologyDescEs":"Diurno","animalPhenologyDescFr":"Diurne","displayOrder":3},"adult":true,"immature":true}],"animalFoodHabits":[{"animalCagFoodHabitsId":103306,"foodHabits":{"id":1,"foodHabitsDescEn":"Carnivore","foodHabitsDescEs":"Carnívoro","foodHabitsDescFr":"Carnivore","displayOrder":1},"adult":true,"immature":true},{"animalCagFoodHabitsId":103307,"foodHabits":{"id":2,"foodHabitsDescEn":"Piscivore","foodHabitsDescEs":"Piscivore","foodHabitsDescFr":"Piscivore","displayOrder":2},"adult":true,"immature":true},{"animalCagFoodHabitsId":103308,"foodHabits":{"id":3,"foodHabitsDescEn":"Invertivore","foodHabitsDescEs":"Invertívoro","foodHabitsDescFr":"Invertivore","displayOrder":3},"adult":true,"immature":true}]},"occurrenceDelineations":[{"eoSpecsDetailId":1045,"locationUseClass":{"id":2,"locationUseClassDescEn":"Breeding","locationUseClassDescEs":"En reproducción","locationUseClassDescFr":"Reproduction","displayOrder":2},"eoSpecGroupName":"Colonial Seabirds","subtypes":"Breeding Colony, Foraging Area","inferredExtentDistance":2.0,"inferredExtentNotes":"Somewhat arbitrary, but generally very conservative for this group, many members of which travel long distances to foraging grounds.","minimumEoCriteria":"Evidence of historical breeding , or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.","mappingGuidance":"Map foraging areas as separate polygons if they are separated from the breeding colony by areas simply flown over on commuting routes.","separationBarriers":"None.","separationDistanceUnsuitableHabitatat":5.0,"separationDistanceSuitableHabitatat":5.0,"altSeparationProcedure":"Where colonies are closer than 5 kilometers, separate occurrences may be created if research shows little genetic mixing between colonies.","separationJustification":"Occurrences include nesting and foraging areas, but occurrence separations are based on nesting areas (i.e., distance between nesting areas, regardless of foraging locations). Hence, different occurrences may overlap.<br><br>Occurrences are not based on discrete populations or metapopulations. Instead, the separation distance is arbitrarily small such that occurrences are of of practical size for data management purposes. <br><br>Evidence from a number of species of seabirds indicates that even though the 'home ranges' of individual nesting seabirds may be immense when foraging trips are taken into account, little movement or feeding overlap may occur between nearby colonies. For example, Thick-billed Murres may commute up to 170 kilometers one way on a feeding trip from the colony, but birds from a colony only 8 kilometers away may forage in a completely different direction; even birds from different sub-colonies only 1.5 kilometers apart mostly fed in completely separate areas (Gaston and Hipfner 2000).  <br><br>Most seabirds have strong breeding site fidelity; e.g., Thick-billed Murres (Gaston and Hipfner 2000, Gaston et al. 1994), Gray-backed Tern (Mostello et al. 2000), Red-footed Booby (Schreiber et al. 1996).","versionDate":"2004-10-20","versionAuthor":"Cannings, S., and G. Hammerson","versionNotes":null,"lastModified":"2020-04-30T02:04:14.425472Z"},{"eoSpecsDetailId":1046,"locationUseClass":{"id":3,"locationUseClassDescEn":"Nonbreeding","locationUseClassDescEs":"No reproducción","locationUseClassDescFr":"Non-reproduction","displayOrder":3},"eoSpecGroupName":"Colonial Seabirds","subtypes":"Feeding area, Loafing site, Roosting site","inferredExtentDistance":null,"inferredExtentNotes":null,"minimumEoCriteria":"Evidence of recurring presence of flocks of nonbreeding birds (including historical), including nonbreeding birds within the breeding season and breeding individuals outside the breeding season; and potential recurring presence at a given location. Normally only areas where concentrations greater than 25 birds regularly occur for more than 20 days per year would be deemed EOs; the number of individuals may be reduced for very rare species. Be cautious about creating EOs for observations that may represent single events.","mappingGuidance":null,"separationBarriers":"None.","separationDistanceUnsuitableHabitatat":10.0,"separationDistanceSuitableHabitatat":10.0,"altSeparationProcedure":null,"separationJustification":"Separation distance arbitrary; defined this small to aid in conservation planning. Sites more than 10 kilometers apart may be joined as one occurrence if research shows that predominantly the same individuals are using both sites.","versionDate":"2001-03-07","versionAuthor":"Cannings, S.","versionNotes":null,"lastModified":"2020-04-30T02:04:14.425472Z"}],"plantCharacteristics":null,"elementManagement":{"elementGlobalId":102273,"eoManagementGroupName":null,"stewardshipOverview":"Nest in colonies with other waterbirds along the Atlantic coast from New York south to the Gulf coast. In the Northeast region, scarce from New York to Maryland, and the largest colonies in Virginia have declined considerably. Loss of upland foraging sites and island nesting sites has probably been the greatest threat to populations, although predation and competition with gulls, and human disturbance at colonies have also contributed to population declines. Protection of nesting tern colonies by posting, gull control, and creation of artificial nesting islands are management techniques that could assist with recovery of populations. Annual nesting surveys should also be conducted to monitor population status. Research activities should address foraging requirements and movement of populations among colonies as well as the ecology during migration and in winter (Via and Duffy 1992).","impacts":null,"restorationPotential":null,"siteConservationPlansConsidered":"Moller (1981) suggested that successful colonies need both a safe and acceptable nesting site and suitable nearby foraging areas. May be more vulnerable to human actions than terns that feed at sea because of their dependence on terrestrial foraging sites. For example, if upland foraging areas around a protected wetland are being converted from agricultural use to housing, or if fields are succeeding to second-growth forests, there simply may not be enough foraging area to support a colony, no matter how suitable the colony site itself is. There may also be a fundamental difference in foraging suitability of saltmarshes of the \"New England\" and the \"Coastal Plain\" types (Nixon 1982). The former, located from Connecticut to Maine along a subsiding coast, are usually limited in area, so the south shore of Long Island, the northernmost extension of the Coastal Plain marsh, may also mark the northern limit of breeding.","managementMethods":"With the possible exception of the Virginia population, it is unlikely that populations in the Northeast region will be large enough in the near or mid-term future to manage directly at the species-level. Fluctuations in populations in the Northeast are probably heavily influenced by changes in the main population in the Southeast Region. <br><br>Protecting colonies of the waterbirds with which gull-billed terns nest may be the most effective management strategy in the Northeast. Protecting wetlands where they feed is also important, although at present not enough is known about the foraging requirements to recommend such management. Would benefit from management techniques such as those used to protect least tern nesting colonies. Protection of nesting colonies by posting, gull control, and creation of artificial nesting islands are management techniques that could assist recovery of populations (Via and Duffy 1992). <br><br>Nesting colonies should be posted with 200 meter buffers following the recommendations of Erwin (1989), and the posting should be reinforced by appointment of \"tern wardens\" to patrol the colonies. Areas where gulls are competing with gull-billed terns for nesting spaces or where gulls pose a potential predation problem should be considered for some form of gull control or removal. Routine predator control should not be undertaken unless a problem is severe because such efforts may themselves generate considerable disturbance for other nesting waterbirds.","monitoringMethods":"Annual nesting surveys should be conducted within each state where they occur. Surveys should be conducted during mid- to late-incubation to avoid colony desertion during early incubation and mortality of young during late surveys. Surveys should be completed before mid-morning to prevent overheating of untended eggs. Counts at hatching should never be done because they may cause massive loss of chicks. <br><br>Total counts of all tern species are best done by aerial survey, but accurate surveys are probably best conducted on foot because of the difficulty in distinguishing gull-billed terns from other terns when viewed from an aircraft (Erwin 1979). The best method for counting gull-billed terns is to flush adults and count them in the air where their broad wings and white general appearance allow separation from other terns. Total counts are not needed or practical in large colonies, where subcounts are sufficient to determine the ratio of gull-billed to other terns. Surveys should also note presence of nesting gulls and other potential predators. Counts from single colonies or regions need to be interpreted in the context of total regional or national counts. <br><br>Surveys of foraging areas are at least as important as surveys of nesting sites. The land-use category of foraging areas and surrounding drainage areas, i.e. marsh, open-water, agricultural areas, and other land types should be noted and the relative use of each should be measured seasonally.","managementProgramContacts":null,"monitoringProgramContacts":null,"managementResearchPrograms":null,"managementResearchNeeds":"Virtually all aspects of the life cycle and biology need further research. Particular attention should be paid to foraging requirements and population movements of this species (Via and Duffy 1992). How far do the birds feed from colonies? In what habitats? What foods are taken from such habitats and do they affect nesting success? <br><br>Dispersal between colonies also needs to be measured, either through banding or biochemical genetic studies. These data would tell us which colonies are responsible for colonizing the northern states and whether local changes in populations are caused by changes in local reproductive success or immigration. <br><br>As a southern species intruding into the Northeast region, the terns may be a sensitive indicator of climate change and global warming (Duffy and Nettleship, in press). Shifts in breeding range or population distribution might also be early warnings of shifts in marsh habitats. Similarly, because of their terrestrial and marsh foraging habits, gull-billed terns may respond to local differences in pesticide levels more closely than do other terns that feed at sea. <br><br>Finally, almost nothing is known of the ecology or distribution during migration or on the wintering grounds. Changes in numbers on the breeding grounds may be caused by events thousands of miles away. These basic natural history questions remain to be addressed.","biologicalResearchNeeds":"Key research needs include: more frequent and refined population monitoring; better understanding of demographics, metapopulation dynamics, and factors limiting populations; and refinement of our knowledge of subspecies' breeding distributions and wintering ranges (Molina and Erwin 2006).","additionalTopics":null},"occurrenceViabilities":[{"eoRankSpecsDetailId":103792,"eoRankSpecsGroupName":null,"locationUseClass":{"id":1,"locationUseClassDescEn":"Not applicable","locationUseClassDescEs":"No se aplica","locationUseClassDescFr":"Sans objet","displayOrder":1},"excellentViability":null,"goodViability":null,"fairViability":null,"poorViability":null,"viabilityJustification":"Use the Generic Guidelines for the Application of Occurrence Ranks (2008).<br>The Key for Ranking Species Occurrences Using the Generic Approach provides a step-wise process for implementing this method.","versionDate":null,"versionAuthor":null,"versionNotes":null,"lastModified":"2020-05-14T02:21:11.567536Z"}],"references":[{"id":153779,"citation":"American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.","shortCitationAuthor":"American Ornithologists' Union (AOU)","shortCitationYear":1983,"referenceCode":"B83AOU01NAUS","lastModified":"2020-02-25T14:38:12.689104Z"},{"id":134424,"citation":"American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.","shortCitationAuthor":"American Ornithologists' Union (AOU)","shortCitationYear":1998,"referenceCode":"B98AOU01NAUS","lastModified":"2020-02-25T14:38:12.673494Z"},{"id":507348,"citation":"American Ornithologists' Union (AOU). 2006. Forty-seventh supplement to the American Ornithologists' Union Check-list of North American Birds. The Auk 123(3):1926-936.","shortCitationAuthor":"American Ornithologists' Union (AOU)","shortCitationYear":2006,"referenceCode":"A06AOU01EHUS","lastModified":"2020-02-25T18:13:17.492391Z"},{"id":124410,"citation":"Bent, A.C. 1921. Life histories of North American gulls and terns. U.S. Natl. Mus. Bull. 113. Washington, D.C.","shortCitationAuthor":"Bent","shortCitationYear":1921,"referenceCode":"B21BEN01NAUS","lastModified":"2020-02-25T18:12:51.304479Z"},{"id":619413,"citation":"BirdLife International. 2004a. Birds in Europe: population estimates, trends and conservation status. BirdLife Conservation Series No. 12.","shortCitationAuthor":"BirdLife International","shortCitationYear":2004,"referenceCode":"N04BIR01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":463505,"citation":"BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.","shortCitationAuthor":"BirdLife International","shortCitationYear":2004,"referenceCode":"N04BIR0100LA","lastModified":"2020-02-25T14:38:12.704742Z"},{"id":104852,"citation":"Blus, L. J., and C. J. Stafford. 1980. Breeding biology and relation of pollutants to Black Skimmers and Gull-billed Terns in South Carolina. Fish and Wildlife Service, Spec. Sci, Rep. Wildl. 230.","shortCitationAuthor":"Blus and Stafford","shortCitationYear":1980,"referenceCode":"N80BLU01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":158427,"citation":"Braun, M. J., D. W. Finch, M. B. Robbins, and B. K. Schmidt. 2000.  A field checklist of the birds of Guyana.  Smithsonian Institution, Washington, D.C.","shortCitationAuthor":"Braun et al.","shortCitationYear":2000,"referenceCode":"N00BRA0100LA","lastModified":"2020-02-25T14:38:18.84546Z"},{"id":507491,"citation":"Bridge, E. S., A. W. Jones, and A. J. Baker. 2005. A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution. Molecular Phylogenetics and Evolution 35:459-469.","shortCitationAuthor":"Bridge et al.","shortCitationYear":2005,"referenceCode":"A05BRI01EHUS","lastModified":"2020-02-25T18:15:30.08816Z"},{"id":150747,"citation":"Buckley, F. G., and P. A. Buckley. 1972. The breeding ecology of royal terns, STERNA (Thalasseus) MAXIMA MAXIMA. Ibis 114:344-59.","shortCitationAuthor":"Buckley and Buckley","shortCitationYear":1972,"referenceCode":"A72BUC01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":107130,"citation":"Buckley, P. A., and F. G. Buckley. 1984. Seabirds of the north and middle Atlantic coast of the United States: their status and conservation. Pages 101-133 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Buckley and Buckley","shortCitationYear":1984,"referenceCode":"A84BUC01NAUS","lastModified":"2020-02-25T18:12:30.945016Z"},{"id":110054,"citation":"Byrd, M. A., and D. W. Johnston. 1991. Birds. Pages 477-537 in K. Terwilliger, coordinator. Virginia's endangered species: proceedings of a symposium. McDonald and Woodward Publ. Co., Blacksburg, Virginia.","shortCitationAuthor":"Byrd and Johnston","shortCitationYear":1991,"referenceCode":"A91BYR01NAUS","lastModified":"2020-02-25T18:13:19.836167Z"},{"id":158672,"citation":"Chardine, J. W., R. D. Morris, J. F. Parnell, and J. Pierce. 2000a. Status and conservation priorities for Laughing Gull, Gull-billed Terns, Royal Terns and Bridled Terns in the West Indies. Pp. 65-79 in E. A. Schreiber and D. S. Lee (editors) Status and Conservation of West Indian Seabirds. Society of Caribbean Ornithology Special Publication 1, Ruston, Louisiana, USA.","shortCitationAuthor":"Chardine et al.","shortCitationYear":2000,"referenceCode":"A00CHA0100LA","lastModified":"2020-02-25T18:13:01.039044Z"},{"id":106988,"citation":"Clapp, R. B., and P. A. Buckley. 1984. Status and conservation of seabirds in the southeastern United States. Pages 135-155 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Clapp and Buckley","shortCitationYear":1984,"referenceCode":"A84CLA01NAUS","lastModified":"2020-02-25T18:15:29.603775Z"},{"id":116699,"citation":"Clapp, R. B., D. Morgan-Jacobs, and R. C. Banks. 1983. Marine Birds of the Southeastern United States and Gulf of Mexico. Part 3: Charadriiformes. Div. of Biol. Services, U.S. Fish and Wildlife Service, Washington, D.C.","shortCitationAuthor":"Clapp et al.","shortCitationYear":1983,"referenceCode":"N83CLA01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":106025,"citation":"Cooper, J., A. J. Williams, and P. L. Britton. 1984. Distribution, population sizes and conservation of breeding seabirds in the Afrotropical region. Pages 403-419 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Cooper et al.","shortCitationYear":1984,"referenceCode":"A84COO01NAUS","lastModified":"2020-02-25T18:14:48.228138Z"},{"id":142837,"citation":"Cramp, S., editor. 1985. Handbook of the birds of Europe, the Middle East, and North Africa. The birds of the western Palearctic. Vol. 4, terns to woodpeckers. Oxford University Press, Oxford, England.","shortCitationAuthor":"Cramp","shortCitationYear":1985,"referenceCode":"B85CRA01NAUS","lastModified":"2020-02-25T18:12:32.679469Z"},{"id":139725,"citation":"Cullen, J. M. 1960. Some adaptations in the nesting behavior of terns. Proc. 12th Intl. Ornithol. Congr. 153-7.","shortCitationAuthor":"Cullen","shortCitationYear":1960,"referenceCode":"A60CUL01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":111408,"citation":"Duffy, D. C., and D. N. Nettleship. In press. Seabirds: managment problems and research opportunities. In D. McCullough and R. Barret (editors). Wildlife 2001: Populations. Elsevier, The Hague, Netherlands.","shortCitationAuthor":"Duffy and Nettleship","shortCitationYear":2001,"referenceCode":"ANDDUF01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":109940,"citation":"Duffy, D. C., and M. Hurtado. 1984. The conservation and status of seabirds of the Ecuadorian mainland. Pages 231-236 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Duffy and Hurtado","shortCitationYear":1984,"referenceCode":"A84DUF01NAUS","lastModified":"2020-02-25T18:15:47.182177Z"},{"id":148728,"citation":"Erwin, R. M. 1978b. Coloniality in terns: the role of social feeding. Condor 80:211-5.","shortCitationAuthor":"Erwin","shortCitationYear":1978,"referenceCode":"A78ERW02NAUS","lastModified":"2020-02-25T18:15:30.08816Z"},{"id":142287,"citation":"Erwin, R.M. 1979. Coastal waterbird colonies: Cape Elizabeth, ME to VA. U.S. Fish and Wildlife Service Biological Services Program, FWS/OBS-79/10. 212 pp.","shortCitationAuthor":"Erwin","shortCitationYear":1979,"referenceCode":"B79ERW02NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":126135,"citation":"Erwin, R. M. 1980. Breeding habitat used by colonially nesting waterbirds in two mid-Atlantic US regions under different regimes of human disturbance. Biol. Conserv. 18: 39-51.","shortCitationAuthor":"Erwin","shortCitationYear":1980,"referenceCode":"A80ERW01NAUS","lastModified":"2020-02-25T18:16:15.479675Z"},{"id":121732,"citation":"Erwin, R. M. 1989. Responses to human intruders by birds nesting in colonies: experimental results and management guidelines. Colonial Waterbirds 12:104-8.","shortCitationAuthor":"Erwin","shortCitationYear":1989,"referenceCode":"A89ERW01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":127893,"citation":"Evans, P. G. H. 1984b. Status and conservation of seabirds in northwest Europe (excluding Norways and the USSR). Pages 293-321 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Evans","shortCitationYear":1984,"referenceCode":"A84EVA02NAUS","lastModified":"2020-02-25T14:38:21.111106Z"},{"id":154935,"citation":"Forbush, E. H. 1939. Natural history of the birds of eastern and central North America. J. B. May (reviser). Houghton Mifflin Company, Boston, Massachusetts. 554 pp.","shortCitationAuthor":"Forbush","shortCitationYear":1939,"referenceCode":"B39FOR01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":131193,"citation":"Gaston, A. J., and J. M. Hipfner. 2000. Thick-billed Murre (<i>Uria lomvia</i>). No. 497 IN A. Poole and F. Gill, editors, The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.","shortCitationAuthor":"Gaston and Hipfner","shortCitationYear":2000,"referenceCode":"A00GAS01NACA","lastModified":"2020-02-25T18:11:59.475593Z"},{"id":108160,"citation":"Gaston, A. J., et al. 1994. Population parameters of thick-billed murres at Coats Island, Northwest Territories, Canada. Condor 96:935-948.","shortCitationAuthor":"Gaston et al.","shortCitationYear":1994,"referenceCode":"A94GAS01NAUS","lastModified":"2020-02-25T18:11:59.475593Z"},{"id":115395,"citation":"Grinnell, J., and A. Miller. 1944. The distribution of the birds of California. Pacific Coast Avifauna Number 27, Cooper Ornithological Club, Berkeley, California.","shortCitationAuthor":"Grinnell and Miller","shortCitationYear":1944,"referenceCode":"N44GRI01NAUS","lastModified":"2020-02-25T18:13:23.570857Z"},{"id":100210,"citation":"Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.","shortCitationAuthor":"Harrison","shortCitationYear":1978,"referenceCode":"B78HAR01NAUS","lastModified":"2020-02-25T14:38:12.657866Z"},{"id":135974,"citation":"Harrison, H.H. 1975. A field guide to bird's nests in the U.S. east of the Mississippi River. Houghton Mifflin Company, Boston, Massachusetts. 257 p.","shortCitationAuthor":"Harrison","shortCitationYear":1975,"referenceCode":"B75HAR01HQUS","lastModified":"2020-02-25T18:15:02.13461Z"},{"id":107035,"citation":"Harrison, H. H. 1979. A field guide to western birds' nests. Houghton Mifflin Company, Boston. 279 pp.","shortCitationAuthor":"Harrison","shortCitationYear":1979,"referenceCode":"B79HAR01NAUS","lastModified":"2020-02-25T18:11:56.303852Z"},{"id":151227,"citation":"Harrison, P. 1983. Seabirds: An identification guide. Croom Helm, London, England. 448 pp.","shortCitationAuthor":"Harrison","shortCitationYear":1983,"referenceCode":"B83HAR01NAUS","lastModified":"2020-02-25T18:14:39.571764Z"},{"id":158701,"citation":"Hilty, S. J., J. A. Gwynne, and G. Tudor. 2003.  The birds of Venezuela, 2nd edition.  Princeton University Press, Princeton, New Jersey, USA.","shortCitationAuthor":"Hilty et al.","shortCitationYear":2003,"referenceCode":"B03HIL0100LA","lastModified":"2020-02-25T18:13:01.023431Z"},{"id":142956,"citation":"Hilty, S.L. and W. L. Brown. 1986.  A Guide to the Birds of Colombia. Princeton University Press, Princeton, USA. 836 pp.","shortCitationAuthor":"Hilty and Brown","shortCitationYear":1986,"referenceCode":"B86HIL01NAUS","lastModified":"2020-02-25T14:38:18.892356Z"},{"id":155592,"citation":"Howell, S. N. G., and S. Webb. 1995.  A guide to the birds of Mexico and northern Central America. Oxford University Press, Oxford, UK.","shortCitationAuthor":"Howell and Webb","shortCitationYear":1995,"referenceCode":"B95HOW01NAUS","lastModified":"2020-02-25T14:38:14.376662Z"},{"id":146167,"citation":"Kress, S. W., E. H. Weinstein, and I. C. T. Nisbet. 1983. The status of tern populations in the northeastern United States and adjacent Canada. Colonial Waterbirds 6:84-106.","shortCitationAuthor":"Kress et al.","shortCitationYear":1983,"referenceCode":"A83KRE02NAUS","lastModified":"2020-02-25T18:15:30.072531Z"},{"id":149566,"citation":"Lind, H. 1963. The reproductive behavior of the gull-billed tern, STERNA NILOTICA Gmelin. Vidensk, Medd. Dan. Naturhist Foren. 155:407-48.","shortCitationAuthor":"Lind","shortCitationYear":1963,"referenceCode":"A63LIN01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":149971,"citation":"Melville, D. S. 1984. Seabirds of China and the surrounding seas. Pages 501-511 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.","shortCitationAuthor":"Melville","shortCitationYear":1984,"referenceCode":"A84MEL01NAUS","lastModified":"2020-02-25T18:14:40.103023Z"},{"id":1131046,"citation":"Molina, K. 2008. Gull-billed Tern (<i>Gelochelidon nilotica</i>) Account in Shuford, W. D., and Gardali, T., editors. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=10400&inline (Accessed 8 June 2023).","shortCitationAuthor":"Molina","shortCitationYear":2008,"referenceCode":"N08MOL01HQUS","lastModified":"2023-08-05T00:58:33.408239Z"},{"id":619414,"citation":"Molina, K. C., and R. M. Erwin. 2006. The distribution and conservation status of the gull-billed tern (<i>Gelochelidon nilotica</i>) in North America. Waterbirds 29:271-295.","shortCitationAuthor":"Molina and Erwin","shortCitationYear":2006,"referenceCode":"A06MOL01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":1131047,"citation":"Molina, K. C., J. F. Parnell, R. M. Erwin, J. del Hoyo, N. Collar, G. M. Kirwan, and E. F. J. Garcia. 2020.¿Gull-billed Tern¿(<i>Gelochelidon nilotica</i>), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.¿https://doi.org/10.2173/bow.gubter1.01","shortCitationAuthor":"Molina et al.","shortCitationYear":2020,"referenceCode":"W20MOL01HQUS","lastModified":"2023-08-05T00:58:33.408239Z"},{"id":118388,"citation":"Moller, A. P. 1975. The breeding population of gull-billed terns GELOCHELIDON NOLOTICA NILOTICA Gmel. in 1972 in Europe, Africa and western Asia, with a review of fluctuations during the present century. Dan. Ornithol. Foren. Tidsskr. 69:1-8.","shortCitationAuthor":"Moller","shortCitationYear":1975,"referenceCode":"A75MOL01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":151523,"citation":"Moller, A. P. 1981. Breeding cycle of the gull-billed tern GELOCHELIDON NOLOTICA Gmel., especially in relation to colony size. Ardea 69:193-8.","shortCitationAuthor":"Moller","shortCitationYear":1981,"referenceCode":"A81MOL01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":129648,"citation":"Moller, A. P. 1982. Coloniality and colony structure in the gill-billed tern. J. fur Ornithologie 123:41-53.","shortCitationAuthor":"Moller","shortCitationYear":1982,"referenceCode":"A82MOL01NAUS","lastModified":"2020-02-25T18:17:18.339781Z"},{"id":148402,"citation":"Morris, R. D., and D. A. Wiggins. 1986. Ruddy turnstones, great horned owls, and egg loss from common tern clutches. Wilson Bulletin 98:101-9.","shortCitationAuthor":"Morris and Wiggins","shortCitationYear":1986,"referenceCode":"A86MOR03NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":107285,"citation":"Mostello, C. S., N. A. Palaia, and R. B. Clapp. 2000. Gray-backed Tern (Sterna lunata). No. 525 in A. Poole and F. Gill (editors). The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 28 pp.","shortCitationAuthor":"Mostello et al.","shortCitationYear":2000,"referenceCode":"A00MOS01NACA","lastModified":"2020-02-25T18:11:59.491215Z"},{"id":152162,"citation":"Nisbet, I. C. T. 1975. Selective effects of predation in a tern colony. Condor 77:221-6.","shortCitationAuthor":"Nisbet","shortCitationYear":1975,"referenceCode":"A75NIS01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":128457,"citation":"Nixon, S. W. 1982. The ecology of New England high salt marshes: a community profile. Fish and Wildlife Service, Washington, D.C. FWS/OBS-81/55. 70 pp.","shortCitationAuthor":"Nixon","shortCitationYear":1982,"referenceCode":"N82NIX01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":158423,"citation":"Parker III, T. A., D. F. Stotz, and J. W. Fitzpatrick. 1996.  Ecological and distributional databases for neotropical birds. The University of Chicago Press, Chicago.","shortCitationAuthor":"Parker et al.","shortCitationYear":1996,"referenceCode":"B96PAR0100LA","lastModified":"2020-02-25T14:38:12.689104Z"},{"id":146543,"citation":"Parnell, J. F., et al. 1988. Colonial waterbird management in North America. Colonial Waterbirds 11:129-69.","shortCitationAuthor":"Parnell et al.","shortCitationYear":1988,"referenceCode":"A88PAR02NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":146743,"citation":"Parnell, J.F., R.M. Erwin, and K.C. Molina. 1995. Gull-billed Tern (STERNA NILOTICA). In A. Poole and F. Gill, editors, The Birds of North America, No. 140. Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, DC. 20 pp.","shortCitationAuthor":"Parnell et al.","shortCitationYear":1995,"referenceCode":"N95PAR01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":143263,"citation":"Pemberton, J. R. 1927. The American gull-billed tern breeding in California. Condor 29:253-8.","shortCitationAuthor":"Pemberton","shortCitationYear":1927,"referenceCode":"A27PEM01NAUS","lastModified":"2020-02-25T18:17:18.324162Z"},{"id":158711,"citation":"Poole, A. F. and F. B. Gill. 1992. The birds of North America. The American Ornithologists' Union, Washington, D.C. and The Academy of Natural Sciences, Philadelphia, PA.","shortCitationAuthor":"Poole and Gill","shortCitationYear":1992,"referenceCode":"B92POO0100LA","lastModified":"2020-02-25T14:38:12.673494Z"},{"id":123535,"citation":"Raffaele, H. A. 1983a. A guide to the birds of Puerto Rico and the Virgin Islands. Fondo Educativo Interamericano, San Juan, Puerto Rico. 255 pp.","shortCitationAuthor":"Raffaele","shortCitationYear":1983,"referenceCode":"B83RAF01NAUS","lastModified":"2020-02-25T14:38:18.861079Z"},{"id":110533,"citation":"Raffaele, H., J. Wiley, O. Garrido, A. Keith, and J. Raffaele. 1998. A guide to the birds of the West Indies. Princeton University Press, Princeton, NJ. 511 pp.","shortCitationAuthor":"Raffaele et al.","shortCitationYear":1998,"referenceCode":"B98RAF01NAUS","lastModified":"2020-02-25T14:38:14.376662Z"},{"id":129005,"citation":"Reichel, J. D., and P. O. Glass. 1991. Checklist of the birds of the Mariana Islands. Elepaio 50:3-11.","shortCitationAuthor":"Reichel and Glass","shortCitationYear":1991,"referenceCode":"A91REI02NAUS","lastModified":"2020-02-25T18:15:06.400288Z"},{"id":158709,"citation":"Ridgely, R. S. 2002. Distribution maps of South American birds. Unpublished.","shortCitationAuthor":"Ridgely","shortCitationYear":2002,"referenceCode":"M02RID0100LA","lastModified":"2020-02-25T14:38:14.361032Z"},{"id":155977,"citation":"Ridgely, R. S. and J. A. Gwynne, Jr. 1989.  A Guide to the Birds of Panama. 2nd edition. Princeton University Press, Princeton, USA.","shortCitationAuthor":"Ridgely and Gwynne","shortCitationYear":1989,"referenceCode":"L89RID0100LA","lastModified":"2020-02-25T14:38:14.361032Z"},{"id":158648,"citation":"Ridgely, R. S. and P. J. Greenfield. 2001.  The birds of Ecuador: Status, distribution, and taxonomy.  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MAXIMA), sandwich terns, and/or caspian terns (S. CASPIA). Most of the gull-billed tern colonies studied in Virginia and North Carolina were small (mean = 45 birds) (Erwin 1978), but colony size ranges up to several hundred along the Gulf Coast. <br><br>Distances between nests ranges from two to 114 meters, with a mean of 21 meters (Sears, pers. comm., cited by Cramp 1985), although the inter-nest distance may vary as a function of colony size (Moller 1982). Vegetation in nesting areas is sparse, e.g., approximately 15% of the ground was covered in a North Carolina colony (Soots and Parnell 1975). <br><br>Clutch size is one to three eggs (Bent 1921, Sears 1978, Moller 1981) and occasionally four (Bent 1921, Forbush 1939, Pemberton 1927, Harrison 1978). Clutch size in one study was found to be significantly greater in larger colonies (Moller 1981). Renesting attempts usually result in smaller clutches (Sears 1978). <br><br>Display a variety of behaviors related to courtship or nest defense. Ritualized courtship behavior, for example, include aerial flights, a variety of terrestrial displays, and courtship feeding (Bent 1921, Lind 1963, Sears 1976, 1981). Defecating away from the nest may reduce the risk posed by nest predators (Sears 1978). They also frequently remove eggshells from the nest after hatching (Cullen 1960), but this response is not as strong as it with other tern species, probably because the cryptically-colored young leave the nest several days after hatching (Sears 1978). <br><br>The eggs are incubated by both the male and the female for 22-24 days (Harrison 1975), and only one brood is raised per season (Bent 1921, Forbush 1939). The major factors that determine the time at which the young leave the nest are the age of the chicks, the proximity of vegetation, and disturbance (Sears 1978). The young are tended by both parents and fledge at four to five weeks of age (Harrison 1975). <br><br>Nesting success appears to be low, with many colonies producing no young at all (Blus and Stafford 1980). The main causes of breeding failure are flooding of low-lying colonies, disturbance by humans, and predation (Clapp et al. 1983).","ecologyComments":null,"habitatComments":"ALL SEASONS: Coastlines, salt marshes, estuaries, lagoons, plowed fields, and less frequently along rivers, around lakes, and in freshwater marshes (Clapp et al. 1983). <br><br>BREEDING: This is a marsh-nesting tern along the coast of New Jersey (Wilson 1840, Stone 1908). Bent (1921) concluded that it had been driven to nest on barrier beaches because of hunting at sites on inner dunes, saltmarshes, and islands. Nesting sites are presently confined to sandy barrier islands, beaches, sandy shores of saline lagoons and marshes, and artificially-produced dredge spoil islands (Clapp et al. 1983). Regional differences in nest sites occur, with the percentage nesting on spoil islands ranging from 28% in New Jersey to 60-80% in North Carolina and 70-84% in Texas (Clapp et al. 1983). Some nest on rooftops in Louisiana (Wiedenfeld and Swan 2000).<br><br>Nests are generally located close to landmarks, such as plants or pieces of driftwood, and are usually slight depressions with rims of dried straw and/or shell fragments (Harrison 1975, Sears 1978). Some nests are more elaborate piles of accumulated shell fragments, which may serve to provide protection from drifting sands (Sears 1978). The appearance of the nest lining varies greatly between nests and from day to day in the same nest, depending on the individual, the time available for placing the lining, and weather conditions (Sears 1976, 1978). <br><br>NONBREEDING: Gull-billed terns sleep and loaf on dikes, mudflats, and sandspits (Stiles and Skutch 1989).","generalDescription":"PLUMAGES: This is a stout, white, blunt-billed tern that feeds in the marshes and adjacent coastal uplands of the southern and Gulf coasts of the U.S. (Forbush 1939, Harrison 1983, Cramp 1985). It is similar in size to other medium-sized terns. This tern's flight is usually more buoyant and gull-like than that of other terns (Vinicombe and Harris 1989). While in breeding plumage, a black cap extends from the lores, including the eyes, to the nape. The rest of the upper parts, wings, and tail are a pale pearl gray. The side of the head, underparts, wing linings, tail, and underwing coverts are white. The primaries are grayish-black underneath and frosty-gray above. The legs and feet are black. The heavy black bill lacks the sharp tip of other terns and is stouter and proportionately shorter. The sexes are similar in appearance. Winter plumage is similar to the breeding plumage except that the black cap is nearly absent, with only some remnant spotting near the rear of the crown. A blackish patch extends from the eye to the auriculars, although the extent of this is quite variable (Harrison 1983, Cramp 1985). <br><br>Recently fledged juveniles are similar to adults in winter plumage except that the head is darker with more blackish spots and the gray back and upper wing are edged in tan, giving the back and wing a buff-colored appearance when the bird is in flight. The downy young are variable in appearance but generally cream, buff, or peach colored, with darker down on the dorsal surfaces. Young usually have two dorsal stripes on the crown, nape, and back and a distinctive dark smudge behind the eye. The bill is typically light pink at hatching and darkens with age. The feet are light pink and darken to an orange-brown with age (Harrison 1983, Cramp 1985). <br><br>VOCALIZATIONS: The typical call is a nasal \"tee-hee-hee\" or \"kat-y-did\" (Bent 1921). Terns attacking terrestrial predators will frequently utter a harsh \"grack\" call during defensive dives (Sears 1981). Other calls are described by Bent (1921), Sears (1981), and Cramp (1985). <br><br>EGGS: The background color of the eggs may vary from buff to olive and the mottling is somewhat finer grained than the pattern of the common tern egg. The eggs have a characteristic \"frosty\" appearance which also distinguishes gull-billed tern eggs from the those of the common tern (STERNA HIRUNDO) (Bent 1921, Harrison 1975). The eggs of the gull-billed tern are cryptically colored, and the immediate area of the nest is not white-washed.","diagnosticCharacteristics":"Lacks the long tail streamers of common terns (STERNA HIRUNDO), Forster's terns (S. FORSTERI), and roseate terns (S. DOUGALLII) terns. It is also longer-legged and broader-winged. It can be told from the sandwich tern (S. SANDVICENSIS) by its shorter beak and tail, shallower wingbeat in flight, and more upright posture while sitting.","speciesMarineHabitats":[],"speciesTerrestrialHabitats":[{"cagTerrHabId":-107622,"terrestrialHabitat":{"id":16,"terrestrialHabitatDescEn":"Sand/dune","terrestrialHabitatDescEs":"Arena/duna","terrestrialHabitatDescFr":"Dune","displayOrder":18}},{"cagTerrHabId":-107623,"terrestrialHabitat":{"id":19,"terrestrialHabitatDescEn":"Cropland/hedgerow","terrestrialHabitatDescEs":"Tierras cultivadas/cerco vivo","terrestrialHabitatDescFr":"Terre cultivée/haie","displayOrder":22}}],"speciesRiverineHabitats":[],"speciesPalustrineHabitats":[{"cagPalusHabId":-102045,"palustrineHabitat":{"id":6,"palustrineHabitatDescEn":"Riparian","palustrineHabitatDescEs":"Ribereño","palustrineHabitatDescFr":"Riverain","displayOrder":6}}],"speciesLacustrineHabitats":[],"speciesSubterraneanHabitats":[],"speciesEstuarineHabitats":[{"cagEstuarineHabId":-100745,"estuarineHabitat":{"id":1,"estuarineHabitatDescEn":"Bay/sound","estuarineHabitatDescEs":"Bahía/Estrecho","estuarineHabitatDescFr":"Baie/détroit","displayOrder":1}},{"cagEstuarineHabId":-100746,"estuarineHabitat":{"id":2,"estuarineHabitatDescEn":"River mouth/tidal river","estuarineHabitatDescEs":"Desembocadura del río/río de marea","estuarineHabitatDescFr":"Embouchure/rivière à marées","displayOrder":2}},{"cagEstuarineHabId":-100747,"estuarineHabitat":{"id":3,"estuarineHabitatDescEn":"Lagoon","estuarineHabitatDescEs":"Laguna","estuarineHabitatDescFr":"Lagune","displayOrder":3}},{"cagEstuarineHabId":-100748,"estuarineHabitat":{"id":4,"estuarineHabitatDescEn":"Tidal flat/shore","estuarineHabitatDescEs":"Marea plana/orilla","estuarineHabitatDescFr":"Replat de marée/rivage","displayOrder":4}},{"cagEstuarineHabId":-100749,"estuarineHabitat":{"id":5,"estuarineHabitatDescEn":"Herbaceous wetland","estuarineHabitatDescEs":"Humedal herbáceo","estuarineHabitatDescFr":"Terre humide herbacée","displayOrder":5}}]},"primaryReference":{"id":507348,"citation":"American Ornithologists' Union (AOU). 2006. Forty-seventh supplement to the American Ornithologists' Union Check-list of North American Birds. The Auk 123(3):1926-936.","shortCitationAuthor":"American Ornithologists' Union (AOU)","shortCitationYear":2006,"referenceCode":"A06AOU01EHUS","lastModified":"2020-02-25T18:13:17.492391Z"},"predecessors":[],"elementGlobalThreatAssessments":[]}