Argentina, Aruba, Belize, Bolivia, Brazil (B), Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Netherlands Antilles, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Venezuela.
Population
Estimated population is 500,000 - 4,999,999 (2010).
Boat-billed Heron (Cochlearius cochlearius) [XC721608]
by Kent Livezey from El Valle de Ant\u00f3n, Cocl\u00e9 Province, Panama (song)
Boat-billed Heron (Cochlearius cochlearius) [XC441050]
by Manuel Grosselet from El Casta\u00f1o, Mapastepec, Chiapas, Mexico (call)
Subspecies
The three northern subspecies sometimes considered a separate species, Cochlearius zeledoni. Birds from north-western Costa Rica, currently placed in subspecies panamensis, are intermediate between the two groups.
The following 5 subspecies are recognised:
zeledoni (Ridgway, 1885) - West-central Mexico.
phillipsi Dickerman, 1973 - Eastern Mexico and Belize.
ridgwayi Dickerman, 1973 - Southern Mexico to western Honduras and El Salvador.
panamensis Griscom, 1926 - Costa Rica and Panama.
cochlearius (Linnaeus, 1766) - Eastern Panama to Guianas, and Amazonia south to north-eastern Argentina.