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) [XC694757]
by Kent Livezey from Selva Bananito, Lim\u00f3n, Costa Rica (call)
Boat-billed Heron (Cochlearius cochlearius) [XC623980]
by Dante Buzzetti from Ventanilla, Mazunte, Santa Mar\u00eda Tonameca, Oaxaca, 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.