Migration.—The probable route of the prothonotary warbler between its summer and winter homes is across the Gulf of Mexico, from the Yucatan peninsula where it occurs in both spring and fall migration. The casual or accidental occurrences of this warbler in Cuba (Habana); Jamaica; and St. Croix, Virgin Islands, are in migration.
Late dates of spring departure are: Colombia—Villavieja, February 5. Panamá; Canal Zone—Barro Colorado, March 10. Nicaragua—Edén, March 23. Quintana Roo—Cozumel, April 6. Cuba—Habana, April 4.
Early dates of spring arrival are: Yucatán—Mérida, March 28. Jamaica—Black River, February 28. Cuba—Habana, March 31. Florida—Pensacola, March 18. Alabama—Booth, April 4. Georgia—Fitzgerald, March 21. South Carolina—Yemassee, March 27. North Carolina—Greenville, April 6. Virginia—Suffolk, April 10. Mississippi—Gulfport, March 18. Louisiana—Morgan City, March 10. Texas—Cove, March 28. Arkansas—Huttig, March 31. Missouri—St. Louis, April 17. Kentucky—Bowling Green, April 5. Illinois—Murphysboro, April 17. Ohio—Berlin Center, April 18. Michigan—Grand Rapids, May 3. Iowa—Iowa City, April 26. Wisconsin—Madison, May 2. Minnesota—Red Wing, May 7. Oklahoma—Tulsa, April 2. Kansas—Manhattan, April 26. Nebraska—Blue Springs, April 30.
Late dates of fall departure are: Nebraska—Watson, September 1. Oklahoma—Oklahoma City, September 14. Texas—Kemah, September 11. Wisconsin—Racine, September 22. Iowa—Sioux City, August 31. Michigan—Three Rivers, September 13. Ohio—Columbus, October 5. Illinois—Oak Park, October 17. Kentucky—Lexington, October 6. Tennessee—Elizabethton, October 19. Louisiana—Monroe, October 8. Mississippi—Deer Island, September 27. North Carolina—Raleigh, August 26. South Carolina—Charleston, September 17. Georgia—Atlanta, October 8. Yucatán—Chichén-Itzá, October 18.
Early dates of fall arrival are: Florida—Fort Myers, August 8. Yucatán—Chichén-Itzá, October 7. Honduras—Tela, September 8. Nicaragua—Río Escondido, September 2. Costa Rica—Bonilla, August 28. Panamá—Obaldia, September 15. Colombia—Gaira, September 11.
Banding records.—Banding provides a hint as to the life-span of the prothonotary warbler. One banded as an immature on June 16, 1940, in Convis township, Calhoun County, Mich., was color banded when it returned to the same place in 1942. Subsequently it was identified by the colored band on May 14, 1944, and May 10, 1945.
Casual records.—The prothonotary warbler was reported at Nassau, Bahamas, on August 29, 1898. It has been twice reported at Bermuda: one shot from a flock in the fall of 1874, and another specimen collected in November 1903. A single bird was observed at Mammoth Hot Springs, Yellowstone Park, Wyo., on September 10, 1931. There are two records for Arizona. On May 1, 1884, a specimen was taken near Tucson at an altitude of 2,300 feet, the highest record of the species in the United States. Another specimen was taken September 8, 1924, at Cave Creek, 4 miles northeast of Paradise in the Chiricahua Mountains.
Egg dates. Florida: 8 records, April 18 to May 9; 5 records, April 28 to 30.
Illinois: 79 records, May 6 to June 21; 46 records, May 20 to June 4, indicating the height of the season.
Iowa: 56 records, May 15 to June 26; 36 records, May 27 to June 6 (Harris).