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Egretta thula

(Molina, 1782)

Snowy Egret

G5Secure Found in 33 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
Identity
Unique IDELEMENT_GLOBAL.2.100485
Element CodeABNGA06030
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderPelecaniformes
FamilyArdeidae
GenusEgretta
Other Common Names
Aigrette neigeuse (FR) Garcinha-Branca, Garça-Pequena (PT) Garcita Blanca, Garceta Pie-Dorado (ES) snowy egret (EN)
Concept Reference
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 The Auk]. Also available online: http://www.aou.org/.
Taxonomic Comments
May constitute a superspecies with E. garzetta, E. gularis, and E. dimorpha (AOU 1998). Frequently placed in genus leucophoyx (AOU 1983).
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-07
Change Date1996-11-20
Edition Date1994-12-22
Edition AuthorsQureshi, B. Partially revised by G. Hammerson.
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Very large range (U.S. to southern South America), relatively secure on a global level; threatened in some areas by loss/degradation of wetland habitat.
Range Extent Comments
BREEDING: northern California, southern Idaho, Kansas, lower Mississippi Valley, and Gulf and Atlantic coasts north to Maine, south through Mexico and the Antilles to South America (to southern Chile and central Argentina). See Spendelow and Patton (1988) for information on the distribution and abundance of coastal U.S. breeding colonies. NON-BREEDING: northern California, southwestern Arizona, Gulf Coast, and South Carolina southward through the breeding range. In the U.S., areas with the highest densities in winter include the Gulf Coast along the Texas-Louisiana border, the mouth of the Mississippi River, the lower Colorado River, and Florida (Root 1988). Wanders irregularly outside usual range; rare straggler to Hawaii.
Threat Impact Comments
Threats include clearing of flood plain forests, loss and degradation of wetlands. Reduced reproductive success in Idaho was attributed to DDE residues accumulated in the nonbreeding season in Mexico (Findholt 1984).
Ecology & Habitat

Description

A small white wading bird with a slim, pointed, black bill; long legs are all black or black with yellow-green on the back side (juveniles); toes yellow; breeding adult has long plumes on head, neck, and back; lores yellow, turning red in adults during breeding season; average length 61 cm, wingspan 104 cm.

Diagnostic Characteristics

Differs from great egret in being much smaller (length 61 cm vs. 99 cm) and in having a black bill rather than a yellow one. Differs from immature little blue heron in having predominantly dark legs (vs. dull yellow), a slimmer mostly black bill (vs. two-toned with gray base and dark tip), and usually paler wing tips. Differs from cattle egret in being larger (length 61 cm vs. 51 cm), slim rather than stocky, and in having a black bill (vs. yellow or red-orange) and predominantly dark legs (vs. yellow or dusky-red). Differs from rare white-phase adult reddish egret in having yellow toes and lacking a two-toned pink-and-black bill.

Habitat

Marshes, lakes, ponds, lagoons, mangroves, and shallow coastal habitats.

Nests in trees or shrubs or, in some areas, on ground or in marsh vegetation. Often nests with other colonial water birds. Nests over water or ground. See references in Spendelow and Patton (1988) for further details.

Ecology

Usually occurs in loose groups. Roosts usually communally.

Reproduction

Eggs are laid usually April to May or June in north; nests in Trinidad May-October, May-August in Costa Rica. Clutch size usually is 4-5 in north, 2-4 in south. Incubation lasts 18 days or longer, by both sexes. Young leave nest at 20-25 days. May first breed at one year. Often nests in large colonies.
Palustrine Habitats
HERBACEOUS WETLANDFORESTED WETLANDRiparian
Other Nations (2)
United StatesN5B,N5N
ProvinceRankNative
TexasS5BYes
MassachusettsS2B,S4NYes
OklahomaSNRBYes
FloridaS3Yes
MaineS3BYes
KentuckyS1BYes
ColoradoS2BYes
North CarolinaS2B,S3NYes
New YorkS2Yes
MissouriS1Yes
KansasS2BYes
New JerseyS3B,S4NYes
GeorgiaS4Yes
MarylandS3BYes
ConnecticutS1BYes
IllinoisSNRYes
NevadaS4BYes
VirginiaS2B,S3NYes
CaliforniaS4Yes
WyomingS1BYes
MinnesotaSNAYes
ArkansasS2BYes
UtahS4BYes
South DakotaS2BYes
IowaS2NYes
OregonS2BYes
MississippiS4Yes
DelawareS1BYes
Navajo NationS4MYes
South CarolinaS2Yes
NebraskaSNRNYes
MichiganSNRNYes
WashingtonSNAYes
IdahoS2BYes
District of ColumbiaS2NYes
LouisianaS4N,S5BYes
Rhode IslandS1BYes
New HampshireSNAYes
IndianaSNAYes
TennesseeS2B,S3NYes
New MexicoS3B,S4MYes
PennsylvaniaS2MYes
AlabamaS4Yes
ArizonaS2B,S4NYes
OhioS1Yes
CanadaN1B
ProvinceRankNative
ManitobaS1BYes
QuebecSNAYes
OntarioSNAYes
Nova ScotiaSNAYes
Roadless Areas (33)
Arizona (1)
AreaForestAcres
GoldfieldTonto National Forest15,257
California (19)
AreaForestAcres
CajonSan Bernardino National Forest7,548
CamuesaLos Padres National Forest8,209
Cucamonga BSan Bernardino National Forest11,933
Deep CreekSan Bernardino National Forest23,869
Fish CanyonAngeles National Forest29,886
Garcia MountainLos Padres National Forest7,850
Glass MountainInyo National Forest52,867
Greenhorn CreekSequoia National Forest28,226
Malduce BuckhornLos Padres National Forest14,177
MonoLos Padres National Forest28,141
NordhoffLos Padres National Forest12,031
Red MountainAngeles National Forest8,034
San SevaineSan Bernardino National Forest6,866
Sespe - FrazierAngeles National Forest4,254
TequepisLos Padres National Forest9,080
TuleAngeles National Forest9,861
WestforkAngeles National Forest4,407
WildhorseCleveland National Forest1,483
Wonoga Pk.Inyo National Forest11,272
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Nevada (3)
AreaForestAcres
Bald Mtn.Humboldt-Toiyabe National Forest41,598
Pearl PeakHumboldt-Toiyabe National Forest71,405
South SchellHumboldt-Toiyabe National Forest125,614
South Dakota (1)
AreaForestAcres
Indian CreekBuffalo Gap National Grassland24,666
Texas (1)
AreaForestAcres
Big CreekNational Forests in Texas1,447
Utah (6)
AreaForestAcres
418029Uinta National Forest15,673
HogsbackWasatch-Cache National Forest7,936
South FrancisWasatch-Cache National Forest3,374
Stump CreekCaribou National Forest355
Swan Creek MountainWasatch-Cache National Forest9,390
WellsvilleWasatch-Cache National Forest1,717
Wyoming (1)
AreaForestAcres
Salt River RangeBridger-Teton National Forest235,661
References (26)
  1. American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
  2. 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/.
  3. BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.
  4. 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.
  5. Castro, I. and A. Phillips. 1996. A guide to the birds of the Galapagos Islands. Princeton University Press, Princeton, New Jersey, USA.
  6. Dumas, J. V. 2000. Roseate Spoonbill (AJAIA AJAJA). No. 490 IN A. Poole and F. Gill, editors, The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.
  7. Findholt, S. L. 1984. Organochlorine residues, eggshell thickness, and reproductive success of snowy egrets nesting in Idaho. Condor 86:163-169.
  8. Fleury, B. E., and T. W. Sherry. 1995. Long-term population trends of colonial wading birds in the southern United States: the impact of crayfish aquaculture on Louisiana populations. Auk 112:613-632.
  9. Hilty, S.L. and W. L. Brown. 1986. A Guide to the Birds of Colombia. Princeton University Press, Princeton, USA. 836 pp.
  10. Howell, S. N. G., and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, Oxford, UK.
  11. National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.
  12. Palmer, R. S. (editor). 1962. Handbook of North American birds. Vol. 1. Loons through flamingos. Yale University Press, New Haven. 567 pp.
  13. 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.
  14. Payne, R. B., and C. J. Risley. 1976. Systematics and evolutionary relationships among the herons (Ardeidae). Univ. Michigan Mus. Zool., Misc. Publ. No. 150. 115 pp.
  15. Powell, G.V.N. 1987. Habitat use by wading birds in a subtropical estuary: implications of hydrography. Auk 104:740-749.
  16. Pratt, H. D., P. L. Bruner, and D. G. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, New Jersey. 409 pp. + 45 plates.
  17. 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.
  18. Ridgely, R. S. 2002. Distribution maps of South American birds. Unpublished.
  19. Ridgely, R. S. and J. A. Gwynne, Jr. 1989. A Guide to the Birds of Panama. 2nd edition. Princeton University Press, Princeton, USA.
  20. Root, T. 1988. Atlas of wintering North American birds: An analysis of Christmas Bird Count data. University of Chicago Press. 336 pp.
  21. Sibley, D. A. 2000a. The Sibley guide to birds. Alfred A. Knopf, New York.
  22. Smith, J. P. 1995. Foraging flights and habitat use of nesting wading birds (Ciconiiformes) at Lake Okeechobee, Florida. Colonial Waterbirds 18:139-158.
  23. Spendelow, J. A. and S. R. Patton. 1988. National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-1982. U.S. Fish and Wildlife Service, Biological Report 88(5). x + 326 pp.
  24. Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, New York, USA. 511 pp.
  25. Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
  26. Zook, J. L. 2002. Distribution maps of the birds of Nicaragua, Costa Rica, and Panama. Unpublished.