Breeding range.—The cerulean warbler breeds north to southern Minnesota (Minneapolis); southern Wisconsin (Barahoo Bluffs, Madison, and Racine, possibly as far north as New London); central Michigan (Saginaw, Locke, and Detroit); southern Ontario (Thedford, Plover Mills, Warren, and Delta; perhaps Manotick); and southern New York (Lockport, Rochester, Ithaca, Santa Cruz Park, and Wappingers Creek, Dutchess County). East to southeastern New York (Dutchess County); rarely northeastern Maryland (Towson); southwestern Delaware (Seaford); western Virginia (Charlottesville and Natural Bridge); western North Carolina (Morganton and Pink Beds); and northern Georgia (Lumpkin County and Atlanta). South to north-central Georgia (Atlanta); south-central Alabama (Autaugaville and Greensboro); northern Louisiana (Monroe and Caddo Lake); and northern Texas (Texarkana and Dallas). West to northeastern Texas (Dallas); northeastern Oklahoma (Copan); southeastern Kansas (Independence); eastern Nebraska (Omaha and Pilgrim Hill, Dakota County); western Iowa (Sioux City); and southern Minnesota (Minneapolis).
Winter range.—The winter home of the cerulean warbler is northwestern South America, in the valleys of the Andes from central Colombia (Antioquia, Medellín, and Bogotá) through Ecuador (Río Napo, Sara-yacu, and the Pataza Valley); to southern Perú (Huachipa and Lima). It has also been found occasionally or accidentally in central northern Venezuela (Rancho Grande); and in western Bolivia (Nairapi and Tilotilo near La Paz). Casual in winter or migration in the Cayman Islands and western Cuba.
Migration.—Late dates of spring departure are: Perú—Huambo, March 15. Ecuador—near San José, March 31. Colombia—Buena Vista, March 4. Florida—Pensacola, April 26. Texas—Austin, April 30.
Early dates of spring arrival are: Florida—Dry Tortugas Island, March 23. Alabama—Greensboro, March 26. Georgia—Atlanta, April 13. South Carolina—Clemson (College), April 21. North Carolina—Asheville, April 23. Virginia—Charlottesville, April 13. West Virginia—Wheeling, April 23. Pennsylvania—McKeesport, April 23. New York—Corning, April 25. Louisiana—Grand Isle, March 27. Arkansas—Tillar, April 6. Tennessee—Athens, April 4. Kentucky—Eubank, April 5. Illinois—Olney, April 18. Indiana—Bloomington, April 11. Michigan—Bay City, April 26. Ohio—Toledo, April 20. Ontario—Hamilton, April 25. Missouri—St. Louis, April 12. Iowa—Hillsboro, April 18. Minnesota—Faribault, April 29. Texas—Victoria, March 17. Oklahoma—Copan, March 27. Kansas—Independence, April 24.
Late dates of fall departure are: Ontario—Point Pelee, September 5. Michigan—Detroit, September 5. Ohio—Ashtabula, September 27. Indiana—Whiting, October 4. Illinois—Chicago, September 28. Kentucky—Versailles, September 4. Tennessee—Athens, September 27. Mississippi—Gulfport, September 17. Oklahoma—Copan, October 1. Texas—Austin, September 27. New York—New York, September 18. Pennsylvania—Berwyn, September 29. North Carolina—Raleigh, September 16. Georgia—Augusta, September 16. Alabama—Birmingham, September 21. Florida—Pensacola, September 18. Costa Rica—San José, October 24.
Early dates of fall arrival are: Texas—Austin, July 20. Mississippi—Beauvoir, July 12. Virginia—Sweet Briar, July 20. Georgia—Athens, July 28. Florida—Pensacola, July 23. Costa Rica—Villa Quesada, August 23. Ecuador—Río Oyacachi, August 10. Perú—Huachipa, October 3.
Casual records.—The majority of the cerulean warblers found east of the Allegheny Mountains might be considered as casual. All records for New England should as yet be so considered, though the species has increased in eastern New York in recent years. About 10 individuals have been recorded in Massachusetts; two in Rhode Island, and one in New Hampshire. On June 2, 1924, one was collected at Whitewater Lake, in southwestern Manitoba, the farthest north that the species has been found. There are two records for North Dakota; one near Jamestown on May 28, 1931, and another near Minot on May 24, 1937. A cerulean warbler was recorded near Denver, Colorado, on May 17, 1883, and a specimen collected on September 2, 1936, on Cherry Creek in Douglas County. A bird “observed at the Mimbres during the latter part of April” is the only record for New Mexico. On October 1, 1947, a specimen was collected at the southeastern edge of the Salton Sea in California; and on October 2, 1925, a specimen was collected near La Grulla in the Sierra San Pedro Mártir, Baja California.
Egg dates.—Ontario: 3 records, June 2 to 13.
New York: 22 records, May 29 to July 9; 15 records, June 1 to 4.