Ardea herodias - Linnaeus, 1758
Great Blue Heron
Other English Common Names: great blue heron
Taxonomic Status: Accepted
Related ITIS Name(s): Ardea herodias Linnaeus, 1758 (TSN 174773)
French Common Names: grand héron
Spanish Common Names: Garza Morena
Unique Identifier: ELEMENT_GLOBAL.2.100203
Element Code: ABNGA04010
Informal Taxonomy: Animals, Vertebrates - Birds - Wading Birds
Image 7487

© Larry Master

Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Pelecaniformes Ardeidae Ardea
Genus Size: C - Small genus (6-20 species)
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Concept Reference
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:
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Ardea herodias
Taxonomic Comments: Includes great white heron, formerly considered a distinct species, A. occidentalis. Some authors consider A. herodias, A. cinerea, and A. cocoi conspecific (AOU 1983); the three constitute a superspecies (Butler 1992).
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 06Apr2016
Global Status Last Changed: 20Nov1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: One of North America's most abundant wading bird.
Nation: United States
National Status: N5B,N5N (05Jan1997)
Nation: Canada
National Status: N5B,N3N,N5M (25Jan2018)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (S5), Alaska (S3), Arizona (S5), Arkansas (S3B,S4N), California (S4), Colorado (S3B), Connecticut (S4B), Delaware (S2B), District of Columbia (S4N), Florida (S5), Georgia (S4), Idaho (S5B), Illinois (S4), Indiana (S4B), Iowa (S3B), Kansas (S4), Kentucky (S3B,S4N), Louisiana (S5B,S5N), Maine (S4B), Maryland (S4B,S3S4N), Massachusetts (S4B,S5N), Michigan (S5), Minnesota (SNRB), Mississippi (S5B), Missouri (S5), Montana (S3), Navajo Nation (S3), Nebraska (S4), Nevada (S5), New Hampshire (S4B), New Jersey (S3B,S4N), New Mexico (S4B,S5N), New York (S5), North Carolina (S4B,S5N), North Dakota (SNRB), Ohio (S4), Oklahoma (S5), Oregon (S4), Pennsylvania (S3S4B,S4N), Rhode Island (S2B), South Carolina (SNRB,SNRN), South Dakota (S4B), Tennessee (S4), Texas (S5B), Utah (S4S5), Vermont (S3S4B), Virginia (S3B,S5N), Washington (S4S5B,S5N), West Virginia (S3B,S4N), Wisconsin (S4B), Wyoming (S4B)
Canada Alberta (S3B), British Columbia (S3), Labrador (SNA), Manitoba (S4S5B), New Brunswick (S4B,S4M), Newfoundland Island (S2B,SUM), Nova Scotia (S4B), Ontario (S4), Prince Edward Island (S4B), Quebec (S5), Saskatchewan (S5B), Yukon Territory (SNR)

Other Statuses

Implied Status under the Committee on the Status of Endangered Wildlife in Canada (COSEWIC):PS:SC
IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: BREEDING: southeastern Alaska and southern Canada to southern Mexico, Greater Antilles, Virgin Islands (St. Thomas and Anegada), islands off coastal Venezuela, and on Galapagos. NON-BREEDING: southeastern Alaska, central U.S., and southern New England south to northern South America (mainly to northern Colombia, northern Venezuela). In the U.S. in winter, the highest densities occur along the lower Colorado River, around the Great Salt Lake, and near Aransas National Wildlife Refuge on the Texas coast (Root 1988). Wanders widely outside usual range, a few times to Hawaii. Some subadults may spend summer in nonbreeding range.

Area of Occupancy: >12,500 4-km2 grid cells
Area of Occupancy Comments: Estimate only but probably reasonable given the size of the bird , itshome range size of 2 to 7 kilometers from its breeding colony, and the estimated number of birds, whic his still in the hundreds of thousands.

Number of Occurrences: > 300
Number of Occurrences Comments: Estimate provided by NatureServe Explorer (2014).

Population Size: 100,000 - 1,000,000 individuals
Population Size Comments: National Audubon Society (2014) estimates the continental population for the Great Blue Heron to be 124,000 but specifies the global population as unknown.

Number of Occurrences with Good Viability/Integrity: Very many (>125)
Viability/Integrity Comments: Given its distribution across North America, there should be an average of at least two or three "good" element occurrences across the 50 states and Canadian provinces, which would be 125 element occurrences.

Overall Threat Impact Comments: In Illinois, a public viewing area used once a week by humans 229 m from a rookery did not cause any overt responses from nesting birds (DeMauro 1993). See Vos (1984) for information on response to human disturbance in Colorado.

Short-term Trend: Increase of >10%
Short-term Trend Comments: Populations generally are stable or increasing in most areas. See Spendelow and Patton (1988) for status of coastal U.S. breeding populations. Populations in the south-central U.S. may be benefiting from crayfish aquaculture; bird population increases may be related to favorable foraging opportunities afforded by expanding crayfish aquaculture (herons may prey on small fishes often abundant in ponds) (Fleury and Sherry 1995). Birdlife International (2014) has trend as increasing and noted a 23.4% increase per decade over the last 40 years (Birdlife International, 2014). Breeding Bird Surveys (Sauer, et. al. 2014) estimates an annual increase of 1.62% from 2002 to 2012

Long-term Trend: Increase of >25%
Long-term Trend Comments: Early in the 20th century, Great Blue Herons suffered from unrestricted hunting, but today, with legal protection and greater awareness about conservation, they are among the most abundant wading birds in North America. (National Audubon Society, 2014). Sauer, et. al. (2014) estimate an annual increase of 0.53% per year over the last 46 years, which is equivalent to a net increase of just over 25% over the time period.

Intrinsic Vulnerability: Moderately vulnerable to not intrinsically vulnerable.
Intrinsic Vulnerability Comments: Destruction of wetland habitat can be a serious threat as well as disruption of rookeries early in the breeding season (Natonal Audubon Society, 2014).

Environmental Specificity: Moderate to broad.
Environmental Specificity Comments: Need relatively undisturbed wetlands

Other NatureServe Conservation Status Information

Inventory Needs: Better inventory of population size over its entire range

Protection Needs: Protection from human activity such as environmental contaminants and rookery disturbances

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDING: southeastern Alaska and southern Canada to southern Mexico, Greater Antilles, Virgin Islands (St. Thomas and Anegada), islands off coastal Venezuela, and on Galapagos. NON-BREEDING: southeastern Alaska, central U.S., and southern New England south to northern South America (mainly to northern Colombia, northern Venezuela). In the U.S. in winter, the highest densities occur along the lower Colorado River, around the Great Salt Lake, and near Aransas National Wildlife Refuge on the Texas coast (Root 1988). Wanders widely outside usual range, a few times to Hawaii. Some subadults may spend summer in nonbreeding range.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NN, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
Canada AB, BC, LB, MB, NB, NF, NS, ON, PE, QC, SK, YT

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at

Range Map Compilers: NatureServe, 2002; WILDSPACETM 2002

U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Cochise (04003), La Paz (04012), Maricopa (04013), Pima (04019)*, Pinal (04021), Yavapai (04025), Yuma (04027)
CA Alameda (06001), Butte (06007), Del Norte (06015), El Dorado (06017), Glenn (06021), Humboldt (06023), Imperial (06025), Lake (06033), Lassen (06035), Marin (06041), Mendocino (06045), Merced (06047)*, Modoc (06049), Monterey (06053), Napa (06055), Nevada (06057), Orange (06059), Placer (06061)*, Riverside (06065), Sacramento (06067), San Joaquin (06077), San Luis Obispo (06079), San Mateo (06081), Santa Clara (06085), Santa Cruz (06087), Shasta (06089), Siskiyou (06093), Solano (06095), Sonoma (06097), Stanislaus (06099), Tehama (06103), Trinity (06105), Tulare (06107), Yolo (06113)
CT Fairfield (09001)*, Hartford (09003), Litchfield (09005), Middlesex (09007), New Haven (09009)*, New London (09011), Tolland (09013), Windham (09015)
DE Kent (10001), New Castle (10003), Sussex (10005)
FL Collier (12021), Miami-Dade (12086), Monroe (12087)
IA Allamakee (19005), Appanoose (19007), Clayton (19043)*, Des Moines (19057)*, Dubuque (19061), Emmet (19063), Jackson (19097)*, Lucas (19117), Polk (19153), Scott (19163)*, Wayne (19185)
IN Adams (18001), Allen (18003), Bartholomew (18005), Boone (18011), Brown (18013), Carroll (18015), Cass (18017), Clinton (18023), Crawford (18025), De Kalb (18033), Decatur (18031), Delaware (18035), Elkhart (18039), Fountain (18045), Franklin (18047), Fulton (18049), Gibson (18051), Grant (18053), Hancock (18059), Hendricks (18063), Henry (18065), Howard (18067), Huntington (18069), Jackson (18071), Jasper (18073), Jay (18075), Jefferson (18077), Jennings (18079), Johnson (18081), Kosciusko (18085), La Porte (18091), Lagrange (18087), Lake (18089), Lawrence (18093), Madison (18095), Marion (18097), Marshall (18099), Martin (18101), Miami (18103), Monroe (18105), Montgomery (18107), Newton (18111), Noble (18113), Owen (18119), Parke (18121), Pike (18125), Porter (18127), Posey (18129)*, Pulaski (18131), Putnam (18133), Randolph (18135), Ripley (18137), Rush (18139), Spencer (18147), St. Joseph (18141), Starke (18149), Steuben (18151), Sullivan (18153), Tippecanoe (18157), Vigo (18167), Wabash (18169), Warren (18171), Warrick (18173), Washington (18175), Wayne (18177), Wells (18179), White (18181), Whitley (18183)
KY Allen (21003), Anderson (21005), Ballard (21007), Barren (21009), Bath (21011), Bell (21013), Boone (21015), Boyle (21021), Butler (21031), Caldwell (21033), Calloway (21035), Campbell (21037), Carlisle (21039), Carroll (21041), Casey (21045), Christian (21047), Crittenden (21055), Cumberland (21057), Edmonson (21061), Elliott (21063), Fayette (21067), Fleming (21069), Franklin (21073), Fulton (21075), Gallatin (21077), Garrard (21079), Graves (21083), Grayson (21085), Green (21087), Hardin (21093), Harlan (21095), Harrison (21097), Henderson (21101), Henry (21103), Hickman (21105), Hopkins (21107), Jefferson (21111), Jessamine (21113), Johnson (21115), Kenton (21117), Laurel (21125), Lawrence (21127)*, Lincoln (21137), Livingston (21139), Lyon (21143)*, Madison (21151), Marshall (21157), Mason (21161), McCracken (21145), McLean (21149), Menifee (21165), Mercer (21167), Muhlenberg (21177), Nicholas (21181), Ohio (21183), Oldham (21185), Owen (21187), Pendleton (21191), Pike (21195), Pulaski (21199), Robertson (21201), Rockcastle (21203), Russell (21207), Scott (21209), Shelby (21211), Spencer (21215), Taylor (21217), Todd (21219), Trigg (21221), Trimble (21223), Union (21225), Warren (21227), Webster (21233), Whitley (21235), Woodford (21239)
MA Berkshire (25003), Essex (25009), Franklin (25011), Hampden (25013), Hampshire (25015), Middlesex (25017), Norfolk (25021), Plymouth (25023), Worcester (25027)
MO Adair (29001), Andrew (29003), Atchison (29005), Barry (29009), Barton (29011), Bates (29013), Benton (29015), Boone (29019), Caldwell (29025), Callaway (29027), Camden (29029), Cape Girardeau (29031), Carter (29035), Cass (29037), Cedar (29039), Chariton (29041), Christian (29043), Clark (29045), Clay (29047)*, Clinton (29049), Cole (29051), Cooper (29053), Crawford (29055), Dade (29057), Dallas (29059), Daviess (29061), DeKalb (29063), Dent (29065), Douglas (29067), Franklin (29071), Gasconade (29073)*, Gentry (29075), Greene (29077), Henry (29083), Hickory (29085), Holt (29087), Howard (29089), Howell (29091), Iron (29093)*, Jackson (29095), Jasper (29097), Jefferson (29099), Johnson (29101), Knox (29103), Laclede (29105), Lafayette (29107), Lawrence (29109), Lewis (29111), Lincoln (29113)*, Linn (29115), Livingston (29117)*, Macon (29121), Madison (29123)*, Maries (29125), McDonald (29119), Miller (29131), Mississippi (29133), Moniteau (29135), Monroe (29137), Montgomery (29139), Morgan (29141), New Madrid (29143), Newton (29145), Oregon (29149), Osage (29151), Ozark (29153), Perry (29157), Pettis (29159), Phelps (29161), Platte (29165), Polk (29167), Pulaski (29169), Putnam (29171), Randolph (29175), Ray (29177), Reynolds (29179), Ripley (29181), Saline (29195), Scotland (29199), Scott (29201)*, Shannon (29203), St. Charles (29183), St. Clair (29185), St. Francois (29187)*, Ste. Genevieve (29186), Stone (29209), Taney (29213), Texas (29215), Vernon (29217), Washington (29221)*, Wayne (29223), Webster (29225), Wright (29229)
MT Beaverhead (30001), Big Horn (30003), Blaine (30005), Broadwater (30007), Carbon (30009), Carter (30011), Cascade (30013), Chouteau (30015), Custer (30017), Dawson (30021), Deer Lodge (30023), Fallon (30025), Fergus (30027), Flathead (30029), Gallatin (30031), Garfield (30033), Glacier (30035), Golden Valley (30037), Granite (30039), Hill (30041), Jefferson (30043), Judith Basin (30045), Lake (30047), Lewis and Clark (30049), Liberty (30051), Lincoln (30053), Madison (30057), McCone (30055), Meagher (30059), Mineral (30061), Missoula (30063), Musselshell (30065), Park (30067), Petroleum (30069), Phillips (30071), Pondera (30073), Powder River (30075), Powell (30077), Prairie (30079), Ravalli (30081), Richland (30083), Roosevelt (30085), Rosebud (30087), Sanders (30089), Sheridan (30091), Silver Bow (30093), Stillwater (30095), Sweet Grass (30097), Teton (30099), Treasure (30103), Valley (30105), Wheatland (30107), Wibaux (30109), Yellowstone (30111)
NE Adams (31001), Antelope (31003), Arthur (31005), Banner (31007), Boyd (31015), Brown (31017), Buffalo (31019), Cass (31025), Chase (31029), Cherry (31031), Cheyenne (31033), Clay (31035)*, Custer (31041), Dawes (31045), Dawson (31047), Deuel (31049), Dundy (31057), Franklin (31061), Frontier (31063), Garden (31069), Garfield (31071), Hall (31079), Harlan (31083), Hayes (31085), Hitchcock (31087), Holt (31089), Hooker (31091), Howard (31093)*, Jefferson (31095), Keith (31101), Keya Paha (31103), Kimball (31105), Knox (31107), Lancaster (31109), Lincoln (31111), Loup (31115), Morrill (31123), Nance (31125), Otoe (31131), Pawnee (31133), Phelps (31137), Red Willow (31145), Richardson (31147), Scotts Bluff (31157), Sheridan (31161), Sioux (31165), Thayer (31169), Thomas (31171), Thurston (31173), Webster (31181)
NH Belknap (33001), Carroll (33003), Cheshire (33005), Coos (33007)*, Grafton (33009), Hillsborough (33011), Merrimack (33013), Rockingham (33015), Strafford (33017), Sullivan (33019)*
NJ Atlantic (34001), Burlington (34005), Camden (34007), Cape May (34009), Cumberland (34011), Essex (34013), Gloucester (34015), Hunterdon (34019), Mercer (34021), Middlesex (34023), Monmouth (34025), Morris (34027), Ocean (34029), Passaic (34031), Salem (34033), Somerset (34035), Sussex (34037), Warren (34041)
NY Cayuga (36011), Chautauqua (36013), Clinton (36019), Cortland (36023), Dutchess (36027), Erie (36029), Franklin (36033), Hamilton (36041)*, Jefferson (36045), Livingston (36051), Monroe (36055), Oneida (36065), Onondaga (36067)*, Orange (36071), Orleans (36073), Oswego (36075), Rensselaer (36083), Saratoga (36091), St. Lawrence (36089), Steuben (36101), Sullivan (36105), Washington (36115), Wayne (36117)
PA Adams (42001), Allegheny (42003), Armstrong (42005), Beaver (42007), Bedford (42009), Berks (42011), Blair (42013), Bradford (42015), Bucks (42017), Butler (42019), Cambria (42021), Cameron (42023), Centre (42027), Chester (42029), Clarion (42031), Clearfield (42033), Clinton (42035), Columbia (42037), Crawford (42039), Cumberland (42041), Dauphin (42043)*, Delaware (42045)*, Elk (42047), Erie (42049), Fayette (42051)*, Franklin (42055), Greene (42059), Huntingdon (42061), Indiana (42063), Jefferson (42065), Juniata (42067), Lackawanna (42069), Lancaster (42071), Lawrence (42073), Lebanon (42075), Luzerne (42079), Lycoming (42081), McKean (42083), Mercer (42085), Mifflin (42087), Monroe (42089), Montgomery (42091), Northampton (42095), Northumberland (42097), Pike (42103), Potter (42105), Schuylkill (42107), Somerset (42111), Sullivan (42113), Susquehanna (42115), Tioga (42117), Venango (42121), Warren (42123), Washington (42125), Wayne (42127), Westmoreland (42129), Wyoming (42131), York (42133)
RI Providence (44007)
SC Anderson (45007), Bamberg (45009), Barnwell (45011), Beaufort (45013), Berkeley (45015), Calhoun (45017), Charleston (45019), Oconee (45073), Orangeburg (45075), Williamsburg (45089), York (45091)
SD Aurora (46003), Bennett (46007), Brookings (46011), Brown (46013), Brule (46015), Buffalo (46017), Butte (46019), Campbell (46021), Charles Mix (46023), Clark (46025), Codington (46029), Corson (46031), Custer (46033), Davison (46035), Day (46037), Deuel (46039), Douglas (46043)*, Edmunds (46045), Fall River (46047), Faulk (46049), Gregory (46053)*, Haakon (46055), Hamlin (46057)*, Hand (46059), Harding (46063), Hughes (46065), Hyde (46069), Jackson (46071), Jerauld (46073), Jones (46075), Kingsbury (46077), Lawrence (46081), Lyman (46085), Marshall (46091), McCook (46087), McPherson (46089), Meade (46093), Mellette (46095), Pennington (46103), Perkins (46105), Potter (46107), Roberts (46109), Shannon (46113), Spink (46115), Stanley (46117), Sully (46119), Todd (46121)*, Tripp (46123), Turner (46125), Ziebach (46137)
VT Addison (50001), Bennington (50003), Chittenden (50007), Essex (50009), Franklin (50011), Grand Isle (50013), Lamoille (50015), Orange (50017), Orleans (50019), Rutland (50021), Washington (50023), Windham (50025), Windsor (50027)
WA Adams (53001), Asotin (53003), Benton (53005), Chelan (53007), Clallam (53009), Clark (53011), Columbia (53013), Cowlitz (53015), Douglas (53017), Ferry (53019), Franklin (53021), Garfield (53023), Grant (53025), Grays Harbor (53027), Island (53029), Jefferson (53031), King (53033), Kitsap (53035), Kittitas (53037), Klickitat (53039), Lewis (53041), Lincoln (53043), Mason (53045), Okanogan (53047), Pacific (53049), Pend Oreille (53051), Pierce (53053), San Juan (53055), Skagit (53057), Skamania (53059), Snohomish (53061), Spokane (53063), Stevens (53065), Thurston (53067), Wahkiakum (53069), Walla Walla (53071), Whatcom (53073), Whitman (53075), Yakima (53077)
WV Brooke (54009), Cabell (54011), Calhoun (54013), Doddridge (54017), Gilmer (54021), Jackson (54035), Lincoln (54043), Marion (54049), Marshall (54051), Monongalia (54061), Monroe (54063), Ohio (54069), Pleasants (54073), Pocahontas (54075), Preston (54077), Putnam (54079), Randolph (54083), Ritchie (54085), Wirt (54105)
WY Albany (56001), Big Horn (56003), Campbell (56005), Carbon (56007), Converse (56009), Crook (56011), Fremont (56013), Goshen (56015), Hot Springs (56017), Johnson (56019), Laramie (56021), Lincoln (56023), Natrona (56025), Niobrara (56027), Park (56029), Platte (56031), Sheridan (56033), Sublette (56035), Sweetwater (56037), Teton (56039), Uinta (56041), Washakie (56043), Weston (56045)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Upper Androscoggin (01040001)+*, Piscataqua-Salmon Falls (01060003)+, Pemigewasset (01070001)+, Merrimack (01070002)+, Contoocook (01070003)+, Nashua (01070004)+, Concord (01070005)+, Merrimack (01070006)+, Upper Connecticut (01080101)+, Passumpsic (01080102)+, Waits (01080103)+, Upper Connecticut-Mascoma (01080104)+, Black-Ottauquechee (01080106)+, West (01080107)+, Middle Connecticut (01080201)+, Miller (01080202)+, Deerfield (01080203)+, Chicopee (01080204)+, Lower Connecticut (01080205)+, Westfield (01080206)+, Farmington (01080207)+, Charles (01090001)+, Cape Cod (01090002)+*, Blackstone (01090003)+, Narragansett (01090004)+, Quinebaug (01100001)+, Shetucket (01100002)+, Thames (01100003)+, Housatonic (01100005)+
02 Sacandaga (02020002)+*, Hudson-Hoosic (02020003)+, Middle Hudson (02020006)+, Rondout (02020007)+, Hudson-Wappinger (02020008)+, Hackensack-Passaic (02030103)+, Raritan (02030105)+, Upper Delaware (02040101)+, Lackawaxen (02040103)+*, Middle Delaware-Mongaup-Brodhead (02040104)+, Middle Delaware-Musconetcong (02040105)+, Crosswicks-Neshaminy (02040201)+, Lower Delaware (02040202)+, Schuylkill (02040203)+, Delaware Bay (02040204)+, Brandywine-Christina (02040205)+, Cohansey-Maurice (02040206)+, Broadkill-Smyrna (02040207)+, Mullica-Toms (02040301)+, Great Egg Harbor (02040302)+, Chincoteague (02040303)+, Upper Susquehanna (02050101)+, Chenango (02050102)+, Tioga (02050104)+, Chemung (02050105)+, Upper Susquehanna-Tunkhannock (02050106)+, Upper Susquehanna-Lackawanna (02050107)+, Upper West Branch Susquehanna (02050201)+, Sinnemahoning (02050202)+, Middle West Branch Susquehanna (02050203)+, Bald Eagle (02050204)+, Pine (02050205)+, Lower West Branch Susquehanna (02050206)+, Lower Susquehanna-Penns (02050301)+, Upper Juniata (02050302)+, Raystown (02050303)+, Lower Juniata (02050304)+, Lower Susquehanna-Swatara (02050305)+, Lower Susquehanna (02050306)+, Chester-Sassafras (02060002)+, Choptank (02060005)+, Monocacy (02070009)+, Western Lower Delmarva (02080109)+, Pokomoke-Western Lower Delmarva (02080111)+
03 Black (03040205)+, Upper Catawba (03050101)+, Lower Catawba (03050103)+, Lake Marion (03050111)+, Santee (03050112)+, Cooper (03050201)+, North Fork Edisto (03050203)+, South Fork Edisto (03050204)+, Edisto (03050205)+, Four Hole Swamp (03050206)+, Salkehatchie (03050207)+, Broad-St. Helena (03050208)+, Seneca (03060101)+, Upper Savannah (03060103)+, Middle Savannah (03060106)+, Calibogue Sound-Wright River (03060110)+, Everglades (03090202)+, Florida Bay-Florida Keys (03090203)+, Big Cypress Swamp (03090204)+, Florida Southeast Coast (03090206)+
04 Little Calumet-Galien (04040001)+, St. Joseph (04050001)+, St. Joseph (04100003)+, St. Marys (04100004)+, Chautauqua-Conneaut (04120101)+, Niagara (04120104)+, Oak Orchard-Twelvemile (04130001)+, Upper Genesee (04130002)+*, Lower Genesee (04130003)+, Irondequoit-Ninemile (04140101)+, Salmon-Sandy (04140102)+, Seneca (04140201)+, Oneida (04140202)+, Chaumont-Perch (04150102)+, Upper St. Lawrence (04150301)+, Oswegatchie (04150302)+, Grass (04150304)+, St. Regis (04150306)+, Mettawee River (04150401)+, Otter Creek (04150402)+, Winooski River (04150403)+, Lamoille River (04150405)+, Missiquoi River (04150407)+, Lake Champlain (04150408)+, St. Francois River (04150500)+
05 Upper Allegheny (05010001)+, Conewango (05010002)+, Middle Allegheny-Tionesta (05010003)+, French (05010004)+, Clarion (05010005)+, Middle Allegheny-Redbank (05010006)+, Conemaugh (05010007)+, Kiskiminetas (05010008)+*, Lower Allegheny (05010009)+, Tygart Valley (05020001)+, West Fork (05020002)+, Cheat (05020004)+, Lower Monongahela (05020005)+, Youghiogheny (05020006)+, Upper Ohio (05030101)+, Shenango (05030102)+, Connoquenessing (05030105)+, Upper Ohio-Wheeling (05030106)+, Little Muskingum-Middle Island (05030201)+, Upper Ohio-Shade (05030202)+, Little Kanawha (05030203)+, Middle New (05050002)+, Greenbrier (05050003)+, Lower Kanawha (05050008)+, Lower Guyandotte (05070102)+, Upper Levisa (05070202)+, Lower Levisa (05070203)+, Big Sandy (05070204)+*, Whitewater (05080003)+, Little Sandy (05090104)+, Middle Ohio-Laughery (05090203)+, Licking (05100101)+, South Fork Licking (05100102)+, Lower Kentucky (05100205)+, Upper Green (05110001)+, Barren (05110002)+, Middle Green (05110003)+, Rough (05110004)+, Lower Green (05110005)+, Pond (05110006)+, Upper Wabash (05120101)+, Salamonie (05120102)+, Mississinewa (05120103)+, Eel (05120104)+, Middle Wabash-Deer (05120105)+, Tippecanoe (05120106)+, Wildcat (05120107)+, Middle Wabash-Little Vermilion (05120108)+, Sugar (05120110)+, Middle Wabash-Busseron (05120111)+, Lower Wabash (05120113)+, Upper White (05120201)+, Lower White (05120202)+, Eel (05120203)+, Driftwood (05120204)+, Upper East Fork White (05120206)+, Muscatatuck (05120207)+, Lower East Fork White (05120208)+, Patoka (05120209)+, Upper Cumberland (05130101)+, Rockcastle (05130102)+, Upper Cumberland-Lake Cumberland (05130103)+, Lower Cumberland (05130205)+, Red (05130206)+, Silver-Little Kentucky (05140101)+, Salt (05140102)+, Rolling Fork (05140103)+, Blue-Sinking (05140104)+, Lower Ohio-Little Pigeon (05140201)+, Highland-Pigeon (05140202)+, Lower Ohio-Bay (05140203)+, Tradewater (05140205)+, Lower Ohio (05140206)+
06 Kentucky Lake (06040005)+, Lower Tennessee (06040006)+
07 Upper Minnesota (07020001)+, Lac Qui Parle (07020003)+*, Coon-Yellow (07060001)+, Grant-Little Maquoketa (07060003)+*, Turkey (07060004)+*, Apple-Plum (07060005)+, Lower Wisconsin (07070005)+*, Copperas-Duck (07080101)+*, Flint-Henderson (07080104)+*, Upper Des Moines (07100002)+, Middle Des Moines (07100004)+, Lower Des Moines (07100009)+*, Bear-Wyaconda (07110001)+, North Fabius (07110002)+, South Fabius (07110003)+, The Sny (07110004)+, South Fork Salt (07110006)+, Cuivre (07110008)+*, Peruque-Piasa (07110009)+, Kankakee (07120001)+, Iroquois (07120002)+, Chicago (07120003)+, Cahokia-Joachim (07140101)+, Meramec (07140102)+, Big (07140104)+, Upper Mississippi-Cape Girardeau (07140105)+
08 Lower Mississippi-Memphis (08010100)+, Bayou De Chien-Mayfield (08010201)+, Obion (08010202)+, New Madrid-St. Johns (08020201)+, Upper St. Francis (08020202)+
09 Bois De Sioux (09020101)+, St. Marys (09040001)+
10 Red Rock (10020001)+, Beaverhead (10020002)+, Ruby (10020003)+, Big Hole (10020004)+, Jefferson (10020005)+, Boulder (10020006)+, Madison (10020007)+, Gallatin (10020008)+, Upper Missouri (10030101)+, Upper Missouri-Dearborn (10030102)+, Smith (10030103)+, Sun (10030104)+, Two Medicine (10030201)+, Marias (10030203)+, Teton (10030205)+, Bullwhacker-Dog (10040101)+, Arrow (10040102)+, Judith (10040103)+, Fort Peck Reservoir (10040104)+, Big Dry (10040105)+, Little Dry (10040106)+, Upper Musselshell (10040201)+, Middle Musselshell (10040202)+, Flatwillow (10040203)+, Box Elder (10040204)+, Lower Musselshell (10040205)+, Milk Headwaters (10050001)+, Middle Milk (10050004)+, Big Sandy (10050005)+, Sage (10050006)+, Lodge (10050007)+, Battle (10050008)+, Lower Milk (10050012)+, Frenchman (10050013)+, Beaver (10050014)+, Rock (10050015)+, Prarie Elk-Wolf (10060001)+, Redwater (10060002)+, Charlie-Little Muddy (10060005)+, Big Muddy (10060006)+, Yellowstone Headwaters (10070001)+, Upper Yellowstone (10070002)+, Shields (10070003)+*, Upper Yellowstone-Lake Basin (10070004)+, Stillwater (10070005)+, Clarks Fork Yellowstone (10070006)+, Upper Yellowstone-Pompeys Pillar (10070007)+, Pryor (10070008)+, Upper Wind (10080001)+, Little Wind (10080002)+, Popo Agie (10080003)+, Muskrat (10080004)+, Lower Wind (10080005)+, Badwater (10080006)+, Upper Bighorn (10080007)+, Nowood (10080008)+, Greybull (10080009)+, Big Horn Lake (10080010)+, Dry (10080011)+, North Fork Shoshone (10080012)+, South Fork Shoshone (10080013)+, Shoshone (10080014)+, Lower Bighorn (10080015)+, Little Bighorn (10080016)+, Upper Tongue (10090101)+, Lower Tongue (10090102)+, Middle Fork Powder (10090201)+, Upper Powder (10090202)+, South Fork Powder (10090203)+, Salt (10090204)+, Crazy Woman (10090205)+, Clear (10090206)+, Middle Powder (10090207)+, Little Powder (10090208)+, Lower Powder (10090209)+, Mizpah (10090210)+, Lower Yellowstone-Sunday (10100001)+, Big Porcupine (10100002)+, Rosebud (10100003)+, Lower Yellowstone (10100004)+, O'fallon (10100005)+, Upper Little Missouri (10110201)+, Boxelder (10110202)+, Antelope (10120101)+, Dry Fork Cheyenne (10120102)+, Upper Cheyenne (10120103)+, Lance (10120104)+, Lightning (10120105)+, Angostura Reservoir (10120106)+, Beaver (10120107)+, Hat (10120108)+, Middle Cheyenne-Spring (10120109)+, Rapid (10120110)+, Middle Cheyenne-Elk (10120111)+, Lower Cheyenne (10120112)+, Cherry (10120113)+, Upper Belle Fourche (10120201)+, Lower Belle Fourche (10120202)+, Redwater (10120203)+, Upper Lake Oahe (10130102)+, Lower Lake Oahe (10130105)+, West Missouri Coteau (10130106)+, North Fork Grand (10130301)+, South Fork Grand (10130302)+, South Fork Moreau (10130304)+, Upper Moreau (10130305)+, Fort Randall Reservoir (10140101)+, Bad (10140102)+, Medicine Knoll (10140103)+, Medicine (10140104)+, Crow (10140105)+, Upper White (10140201)+, Middle White (10140202)+, Little White (10140203)+, Lower White (10140204)+, Ponca (10150001)+, Niobrara Headwaters (10150002)+, Upper Niobrara (10150003)+, Middle Niobrara (10150004)+, Keya Paha (10150006)+, Lower Niobrara (10150007)+, Upper James (10160003)+, Elm (10160004)+, Mud (10160005)+, Middle James (10160006)+, East Missouri Coteau (10160007)+, Snake (10160008)+, Turtle (10160009)+, Lower James (10160011)+, Lewis and Clark Lake (10170101)+, Vermillion (10170102)+, South Big Sioux Coteau (10170103)+, Middle Big Sioux Coteau (10170201)+, Upper Big Sioux (10170202)+, Upper North Platte (10180002)+, Pathfinder-Seminoe Reservoirs (10180003)+, Medicine Bow (10180004)+, Little Medicine Bow (10180005)+, Sweetwater (10180006)+, Middle North Platte-Casper (10180007)+, Glendo Reservoir (10180008)+, Middle North Platte-Scotts Bluff (10180009)+, Upper Laramie (10180010)+, Lower Laramie (10180011)+, Horse (10180012)+, Pumpkin (10180013)+, Lower North Platte (10180014)+, Lone Tree-Owl (10190008)+, Crow (10190009)+, Upper Lodgepole (10190015)+, Lower Lodgepole (10190016)+, Lower South Platte (10190018)+, Middle Platte-Buffalo (10200101)+, Lower Platte (10200202)+, Salt (10200203)+, Upper Middle Loup (10210001)+, Dismal (10210002)+, South Loup (10210004)+, Lower North Loup (10210007)+*, Calamus (10210008)+, Loup (10210009)+, Cedar (10210010)+, Upper Elkhorn (10220001)+, Blackbird-Soldier (10230001)+, Keg-Weeping Water (10240001)+, Tarkio-Wolf (10240005)+, Little Nemaha (10240006)+, South Fork Big Nemaha (10240007)+, Nodaway (10240010)+, Independence-Sugar (10240011)+, Platte (10240012)+, One Hundred and Two (10240013)+, Upper Republican (10250004)+, Frenchman (10250005)+, Red Willow (10250007)+, Medicine (10250008)+, Harlan County Reservoir (10250009)+, Lower Sappa (10250011)+, Prairie Dog (10250015)+, Middle Republican (10250016)+, West Fork Big Blue (10270203)+*, Upper Little Blue (10270206)+, Lower Little Blue (10270207)+, Upper Grand (10280101)+, Lower Grand (10280103)+, Upper Chariton (10280201)+, Lower Chariton (10280202)+, Little Chariton (10280203)+, Lower Marais Des Cygnes (10290102)+*, Little Osage (10290103)+, Marmaton (10290104)+, Harry S. Missouri (10290105)+, Sac (10290106)+, Pomme De Terre (10290107)+, South Grand (10290108)+, Lake of the Ozarks (10290109)+, Niangua (10290110)+, Lower Osage (10290111)+, Upper Gasconade (10290201)+, Big Piney (10290202)+, Lower Gasconade (10290203)+, Lower Missouri-Crooked (10300101)+, Lower Missouri-Moreau (10300102)+, Lamine (10300103)+, Blackwater (10300104)+, Lower Missouri (10300200)+
11 Beaver Reservoir (11010001)+, James (11010002)+, Bull Shoals Lake (11010003)+, North Fork White (11010006)+, Upper Black (11010007)+, Current (11010008)+, Spring (11010010)+, Eleven Point (11010011)+, Spring (11070207)+, Elk (11070208)+
14 Upper Green (14040101)+, New Fork (14040102)+, Upper Green-Slate (14040103)+, Big Sandy (14040104)+, Bitter (14040105)+, Upper Green-Flaming Gorge Reservoir (14040106)+, Blacks Fork (14040107)+, Muddy (14040108)+, Vermilion (14040109)+, Great Divide closed basin (14040200)+, Little Snake (14050003)+, Muddy (14050004)+
15 Imperial Reservoir (15030104)+, Lower Colorado (15030107)+, Yuma Desert (15030108)+, Middle Gila (15050100)+, Upper San Pedro (15050202)+, Brawley Wash (15050304)+*, Big Chino-Williamson Valley (15060201)+, Upper Verde (15060202)+, Lower Verde (15060203)+, Agua Fria (15070102)+, Lower Gila (15070201)+
16 Upper Bear (16010101)+, Central Bear (16010102)+
17 Upper Kootenai (17010101)+, Fisher (17010102)+, Yaak (17010103)+, Upper Clark Fork (17010201)+, Flint-Rock (17010202)+, Blackfoot (17010203)+, Middle Clark Fork (17010204)+, Bitterroot (17010205)+, North Fork Flathead (17010206)+, Flathead Lake (17010208)+, Stillwater (17010210)+, Swan (17010211)+, Lower Flathead (17010212)+, Lower Clark Fork (17010213)+, Pend Oreille (17010216)+, Upper Spokane (17010305)+, Hangman (17010306)+, Lower Spokane (17010307)+, Little Spokane (17010308)+, Franklin D. Roosevelt Lake (17020001)+, Kettle (17020002)+, Colville (17020003)+, Chief Joseph (17020005)+, Okanogan (17020006)+, Methow (17020008)+, Upper Columbia-Entiat (17020010)+, Wenatchee (17020011)+, Upper Crab (17020013)+, Lower Crab (17020015)+, Upper Columbia-Priest Rapids (17020016)+, Upper Yakima (17030001)+, Lower Yakima, Washington (17030003)+, Snake headwaters (17040101)+, Gros Ventre (17040102)+, Greys-Hobock (17040103)+, Palisades (17040104)+, Salt (17040105)+, Lower Henrys (17040203)+, Teton (17040204)+, Lower Snake-Tucannon (17060107)+, Palouse (17060108)+, Rock (17060109)+, Lower Snake (17060110)+, Middle Columbia-Lake Wallula (17070101)+, Walla Walla (17070102)+, Middle Columbia-Hood (17070105)+, Lower Columbia-Sandy (17080001)+, Lewis (17080002)+, Lower Columbia-Clatskanie (17080003)+, Upper Cowlitz (17080004)+, Lower Cowlitz (17080005)+, Lower Columbia (17080006)+, Lower Willamette (17090012)+, Hoh-Quillayute (17100101)+, Upper Chehalis (17100103)+, Lower Chehalis (17100104)+, Grays Harbor (17100105)+, Willapa Bay (17100106)+, Chetco (17100312)+, Fraser (17110001)+, Strait of Georgia (17110002)+, San Juan Islands (17110003)+, Nooksack (17110004)+, Upper Skagit (17110005)+, Lower Skagit (17110007)+, Stillaguamish (17110008)+, Snoqualmie (17110010)+, Snohomish (17110011)+, Lake Washington (17110012)+, Duwamish (17110013)+, Puyallup (17110014)+, Nisqually (17110015)+, Deschutes (17110016)+, Skokomish (17110017)+, Hood Canal (17110018)+, Puget Sound (17110019)+, Dungeness-Elwha (17110020)+, Crescent-Hoko (17110021)+
18 Smith (18010101)+, Mad-Redwood (18010102)+, Lower Eel (18010105)+, Mattole (18010107)+, Big-Navarro-Garcia (18010108)+, Russian (18010110)+, Lost (18010204)+, Upper Klamath (18010206)+, Shasta (18010207)+, Scott (18010208)+, Lower Klamath (18010209)+, Trinity (18010211)+, Upper Pit (18020002)+, Lower Pit (18020003)+, Sacramento headwaters (18020005)+, Sacramento-Stone Corral (18020104)+, Lower American (18020111)+, Upper Cache (18020116)+, Upper Yuba (18020125)+, Thomes Creek-Sacramento River (18020156)+, Butte Creek (18020158)+, Upper Coon-Upper Auburn (18020161)+, Lower Sacramento (18020163)+, Upper Kaweah (18030007)+, Middle San Joaquin-Lower (18040001)+*, Middle San Joaquin-Lower (18040002)+, San Joaquin Delta (18040003)+, Upper Mokelumne (18040012)+, Upper Cosumnes (18040013)+, San Pablo Bay (18050002)+, Coyote (18050003)+, San Francisco Bay (18050004)+, Tomales-Drake Bays (18050005)+*, San Francisco Coastal South (18050006)+, San Lorenzo-Soquel (18060001)+, Salinas (18060005)+, San Gabriel (18070106)+, Honey-Eagle Lakes (18080003)+*, Salton Sea (18100204)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: A wading bird (heron).
Reproduction Comments: Clutch size is 3-7, averages larger in north than in south. Incubation, by both sexes, lasts 25-29 days. Both parents tend young, which leave nest in 60-90 days. May breed at 2 years. Nests usually in colonies, a few pairs to 100s; sometimes solitary. Fledging success depends importantly on success of parents in providing sufficient food when nestlings are 2-6 weeks old (Bennett et al. 1995, Auk 112:201-209).
Ecology Comments: Nonbreeding: usually solitary. May establish feeding territories in winter (Stiles and Skutch 1989).
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: Y
Mobility and Migration Comments: Migrates to northern breeding range February-early May; departs northerly localities September-October. Disperses in all compass directions after breeding, before southward migration. Southern populations may be quite sedentary. Present in small numbers in Colombia mainly October to mid-April, in Panama mainly September-April (Ridgely and Gwynne 1989, Hilty and Brown 1986).
Estuarine Habitat(s): Bay/sound, Herbaceous wetland, Lagoon, River mouth/tidal river, Scrub-shrub wetland, Tidal flat/shore
Riverine Habitat(s): Low gradient
Lacustrine Habitat(s): Shallow water
Terrestrial Habitat(s): Forest - Conifer, Forest - Hardwood, Forest - Mixed, Grassland/herbaceous, Old field
Habitat Comments: Freshwater and brackish marshes, along lakes, rivers, bays, lagoons, ocean beaches, mangroves, fields, and meadows. Nests commonly high in trees in swamps and forested areas, less commonly in bushes, or on ground, rock ledges, and coastal cliffs. Often nests with other herons. See Spendelow and Patton (1988) for further details and discussion of geographic variation in nesting sites. Generally nests close to foraging habitat.
Adult Food Habits: Carnivore, Invertivore, Piscivore
Immature Food Habits: Carnivore, Invertivore, Piscivore
Food Comments: Eats fishes, insects, crustaceans, amphibians and reptiles, mice and shrews, and other animals. Forages mostly while standing in water but also in fields; sometimes drops from air or perch into water (Palmer 1962, Terres 1980).
Adult Phenology: Circadian, Crepuscular, Diurnal
Immature Phenology: Circadian, Crepuscular, Diurnal
Phenology Comments: Generally tends to be mainly crepuscular but also is active in daytime and at night. In coastal region, activity often is related to the tidal cycle, independent of day-night cycle in some areas (Powell 1987). Nocturnal foraging activity occurs in nontidal situations as well as in tidal environments (McNeil et al. 1993).
Colonial Breeder: Y
Length: 117 centimeters
Weight: 2576 grams
Economic Attributes Not yet assessed
Management Summary
Biological Research Needs: Better determination of subspecies and their boundaries, gaining a clearer understanding of factors regulation populations, the connectivity among populations, foraging ecology and habitat use at wintering sites, potential impacts of climate change (Vennesland and butler, 2011).
Population/Occurrence Delineation
Group Name: Colonial Wading Birds

Use Class: Breeding
Subtype(s): Foraging Area, Breeding Colony
Minimum Criteria for an Occurrence: 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. Small heron colonies (rookeries or heronries) are often ephemeral in nature; recommend tracking rookeries which maintain a minimum of 15 active nests over 2-3 years. Where concentrations of non-breeding individuals occur within the boundaries of a breeding occurrence (especially if augmented by migrants), consider creating a separate occurrence with Location Use Class 'Nonbreeding.'
Mapping Guidance: Map Foraging Areas in separate polygons from the breeding colony if they are separated from the colony by areas simply flown over on commuting routes.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 10 km
Separation Justification: Occurrences include breeding colonies and foraging areas, but the separation distance pertains to breediing colonies. Hence, difference occurrences may overlap. Unsuitable habitat: upland areas, except those known to be used regularly for foraging (e.g., meadows used by great egrets).

Separation distance is an arbitrary compromise between the high mobility of these birds and the need for occurrences of practical size for conservation planning. Occurrences do not necessarily represent discrete populations or metapopulations.

Colony fidelity low in some species (e.g. Roseate Spoonbill, Dumas 2000; Glossy Ibis, Davis and Kricher 2000).

Feeding areas associated with a breeding colony (i.e. different features of the same occurrence) may be a number of kilometers away from the colony: averaging 12 kilometers for Roseate Spoonbill (Dumas 2000); 7.3 kilometers for Glossy Ibis (Davis and Kricher 2000); 2.8 to more than 5 kilometers for Snowy Egrets (Smith 1995).

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 3 km
Inferred Minimum Extent Justification: A low mean foraging range size for this group.
Date: 28Oct2004
Author: Cannings, S., and G. Hammerson

Use Class: Nonbreeding
Subtype(s): Roost, Foraging area
Minimum Criteria for an Occurrence: Evidence of recurring presence of flocks of non-breeding birds (including historical), including non-breeding 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 10 birds occur regularly for at least 20 days per year would be deemed occurrences. Be cautious about creating occurrences for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 10 km
Separation Distance for Suitable Habitat: 10 km
Separation Justification: Separation distance arbitrary, set at 10 kilometers to define occurrences of manageable size for conservation purposes. Occurrences defined primarily on the basis of areas supporting concentrations of foraging birds, rather than on the basis of distinct populations.
Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 3 km
Inferred Minimum Extent Justification: Based on foraging ranges from breeding rookeries.
Date: 19Apr2002
Author: Cannings, S.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 28Feb2014
NatureServe Conservation Status Factors Author: Duncan, J.
Element Ecology & Life History Edition Date: 30Apr1996
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

  • 1998. The Great Blue Heron. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. 2pp.

  • Alabama Ornithological Society. 2006. Field checklist of Alabama birds. Alabama Ornithological Society, Dauphin Island, Alabama. [Available online at ]

  • Allen, C. R., S. Demarais, and R. S. Lutz. 1994. Red imported fire ant impact on wildlife: an overview. The Texas Journal of Science 46(1):51-59.

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Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

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