Distribution

Breeding Range

In U.S., breeds primarily along immediate coastline of Atlantic Ocean and Gulf of Mexico; breeding extends into coastal plain in the se. U.S., particularly in Florida and along Gulf Coast. Occasionally breeds in Kansas and other interior locations far from coast.

Along Atlantic Coast, has bred irregularly (most records during 1970s and 1980s) north to s. Maine (Stratton I., York Co.; Osborn and Custer 1977), n. Massachusetts (House I., Essex Co.; Veit and Petersen 1993), and sw. Connecticut (Norwalk Is., Fairfield Co.; Bevier 1994). Breeds more regularly along Atlantic Coast of Long I., NY (western portion of south shore; Andrle and Carroll 1988), New Jersey (Long Beach I. south to Cape May; Osborn and Custer 1977), Maryland and Virginia portions of Delmarva Peninsula (Robbins 1996, Virginia Breeding Bird Atlas [BBA] unpubl.), N. Carolina, S. Carolina, and Georgia (Osborn and Custer 1977). Breeds throughout Florida (including inland sites), where most numerous in south and along coasts; least numerous along coast of panhandle (Stevenson and Anderson 1994); and along coastal plain of Alabama, Mississippi, Louisiana, and Texas (Lowery 1955, Portnoy 1977, Texas Colonial Waterbird Society 1982, Dusi and Dusi 1988, Texas BBA unpubl.). Also breeds in upper Delaware Bay (Pea Patch I.; Hess et al. in press), and in lower Chesapeake Bay (Dorchester and Somerset Cos., MD; Robbins 1996).

Has bred up to several hundred kilometers inland in S. Carolina (Berkeley Co., 1 record in 1986; Belser and Post 1987). However, also summers regularly in several counties of central Kansas, particularly Cheyenne Bottoms National Wildlife Refuge (Barton Co.), where breeding has been attempted with varying success since 1974 (Thompson and Ely 1989). Sites of other interior breeding records include several locations in w. and n.-central Texas (occasional to regular in Austin, Colorado, and Marion Cos.; Oberholser 1974, Runnels 1980), rarely to S. Dakota (Skadsen 1986, Meeks et al. 1996) and N. Dakota (Schmidt 1979).

In Middle America, breeds along Pacific Coast from central Sonora, Mexico, south to El Salvador; along Atlantic Coast of Tamaulipas and n. Veracruz, Mexico; and at a few sites along east coast of Yucatán Peninsula, and west coast of s. Baja Peninsula (Howell and Webb 1995). Also recorded breeding on Pajaros I. in Tempesque Basin of w. Costa Rica (Stiles and Skutch 1989), and in Panama on Taborcilla I., w. Panama Province, and less commonly on coast of Herrera Province (Ridgely and Gwynne 1989).

In the Caribbean, breeds on the Bahamas, Cuba, Cayman Is., Jamaica, Hispanola, Puerto Rico, and Virgin Is. (St. Thomas) (Bond 1993, Raffaele 1989, Evans 1990, Wetmore and Swales 1932).

In South America, primarily a coastal bird. Common below 1,000 m in Colombia and Ecuador in brackish or salt water (Hilty and Brown 1986). Occasionally breeds southward on Pacific Coast to s. Peru. On Atlantic Coast of South America, locally common in Venezuela (Margarita, Los Roques, La Orchila Is.; Meyer de Schauensee and Phelps 1978), commonly breeds in large numbers in Suriname and Guyana (DeJonghe et al. 1992, Haverschmidt and Mees 1994); breeds sporadically on northeastern coast of Brazil, probably to mouth of Amazon River (Maranhao and Paui; Blake 1977). Also breeds on Aruba, Curacao, Bonaire (Voous 1983), and Trinidad (ffrench 1991). Southern range of breeding and abundance throughout South America remain poorly documented.

Winter Range

In U.S., winters locally along Atlantic Coast from s. New Jersey and Delaware south (warm winters only; Sibley 1993); more commonly winters from coastal S. Carolina south throughout remainder of breeding range. Numbers decline in northern part of Florida Peninsula during winter (Stevenson and Anderson 1994). Also winters in very small numbers in s. California along coast from city of San Diego south, and very infrequently at Salton Sea, lower Colorado River, and along coast of Orange Co. (Small 1994).

In Middle America, winters coastally throughout Baja California, along both coasts of Mexico and Central America from Sonora and Tamaulipas south to s. Panama, in interior throughout Central Volcanic Belt of Mexico, and from s. Mexico and Yucatán Peninsula south to s. Panama. In Costa Rica, found primarily in lowlands of both slopes, and in Panama primarily on Pacific slope (Ridgely and Gwynne 1989, Stiles and Skutch 1989, Howell and Webb 1995).

A single record for the Azores (Parrott and Philllips 1987).

Between 1940s and 1970s, breeding range expanded northward along East Coast of North America (Ogden 1978, Parnell et al. 1986) in coastal areas from N. Carolina to Maine. First nesting records: Virginia—1941, now regular breeder; Maryland—1958, now regular breeder; New Jersey—1951, now regular breeder; New York—1955, now regular breeder (Andrle and Carroll 1988); Connecticut—1976, now occasional breeder (Bevier 1994); Massachusetts—1976, now rare breeder (Veit and Petersen 1993). Vagrancy and extralimital sightings also increased dramatically since 1970s; large numbers of sightings in northern tier of eastern and midwestern states, Canada, and sw. U.S. (see above). Though reported breeding in California (Scammons and San Ignacio Lagoons; Grinnell 1928) in 1920s, no recent reports of breeding in that state.

Wintering range also expanded northward, with breeding range. Now frequently recorded on Christmas Bird Counts (CBCs) from New Jersey southward on Atlantic Coast; a rare vagrant previously. Only 1 individual noted in Maryland before 1895; first state records were 1937 in Delaware, 1920 in New Jersey, 1925 in New York, and 1940 in Massachusetts. Although Bent (1926) listed this heron as rarely wintering in Louisiana, Fleury and Sherry (1994) demonstrated a rapidly growing winter population there between 1967 and 1993.

Identified from Pleistocene sediments of Florida (Wetmore 1931). Egretta subfluvia, identified from late Miocene and early Pliocene of Florida (Becker 1985), shares some characters with Tricolored Heron. Closely related Little Blue Heron identified from late Pleistocene of California and Florida, and Snowy Egret from Pleistocene of Florida (Wetmore 1931, Brodkorb 1963, Campbell 1980).