Fall.—Dr. Walkinshaw (1938) says that “the majority of the Prothonotaries leave our rivers [Michigan] by the second or third of July. One may canoe some years a good many miles during the latter part of July or the early part of August without finding a single Prothonotary, whereas in other years many groups can be found. The majority evidently are early migrants. Very few remain until late August or early September, the latest date being September 9, 1934, at Battle Creek.”
The 1931 A. O. U. Check-List states that this warbler apparently crosses the Gulf of Mexico in migration “and is not found in Mexico north of Campeche,” but probably some migration is along the coast of Texas and Mexico, as suggested by George G. Williams (1945).
Dr. Chapman (1907) says: “The route of the Prothonotary Warbler in its fall migration is interesting; the breeding birds of the Middle Atlantic States apparently pass southwest to northwestern Florida and then take a seven-hundred-mile flight directly across the Gulf of Mexico to southern Yucatan, instead of crossing to Cuba and thence to Yucatan.”
Alexander F. Skutch writes to me: “Unrecorded from Guatemala, the prothonotary warbler is a rare bird of passage and very rare winter resident in the more southerly portions of Central America. When Carriker published his list of Costa Rican birds in 1910, he had a few records from the highlands—apparently of migrating birds—and from the Pacific lowlands, but none from Caribbean lowlands. But on March 4, 1934, I found it not uncommon at Puerto Limón, where I saw one among the royal palms in Vargas Park, and several among the shrubbery about the outlying cottages, all within a hundred yards of the Caribbean Sea. It has been recorded a number of times from the Canal Zone, but it is not common there. It is almost always seen in the vicinity of water.”
Winter.—Apparently the main winter range is in Colombia and perhaps Venezuela. Referring to Magdalena, Colombia, P. J. Darlington, Jr. (1931), writes: “The Prothonotary Warbler swarms during the winter in the mangroves at Sevillano and in the fresh swamps at Cienaga. It was seen also in bushes on the sea beach at Donjaca September 15, and along the Rio Frio River in the edge of the foothills, where it was especially common in February. The birds usually occur near water, but numbers were noted again and again in yellow-flowering, acacia-like trees on the border of stump land and dry forest, far from water.”
DISTRIBUTION
Range.—Eastern United States to northwestern South America.
Breeding range.—The prothonotary warbler breeds north to southeastern Minnesota (Cambridge, Lake Pekin, and La Crescent); central Wisconsin (New London and Shiocton); southern Michigan (Hesperia, Lansing, and Ann Arbor); northern Ohio (Toledo and Cleveland); extreme southern Ontario (Rondeau); western New York (Buffalo and Oak Orchard); northern West Virginia (Parkersburg); central Maryland (Seneca and Bowie); and southern Delaware (Gumboro). East to southern Delaware (Gumboro); eastern Virginia (Dyke, near Alexandria, and Dismal Swamp); and the Atlantic coast to central Florida (Lake Gentry and Padgett Creek). South to central Florida (Padgett Creek and possibly Puntarossa); the Gulf coast to southeastern Texas (Cove, Houston, and Bloomington). West to central Texas (Bloomington, Fort Worth, and Gainesville); central Oklahoma (Norman and Oklahoma City); eastern Kansas (Emporia and Manhattan); northwestern Iowa (Lake Okoboji); and southeastern Minnesota (Rochester, Red Wing, and Cambridge).
The prothonotary warbler has been recorded as casual or accidental west to southeastern Nebraska (Powell and Lincoln); southeastern South Dakota (Yankton and Sioux Falls); and central Minnesota (Brainerd). North to southern Ontario (London and Hamilton); central New York (Ithaca); Massachusetts (Northampton, Amherst, and Concord); New Hampshire (Concord); and Maine (Matinicus Island and Calais).
Winter range.—The winter home of the prothonotary warbler is in Central America and northwestern South America where it has been found north to northwestern Costa Rica (Bolson); Nicaragua (Escondido River). East to northwestern Venezuela (Mérida and Encontrados); and western Colombia (San José de Cucuta and Villavieja). South to southwestern Colombia (Villavieja); and northwestern Ecuador (Esmeraldas). West to northwestern Ecuador (Esmeraldas); western Colombia (Antioquia); western Panamá (Paracote and David); and Costa Rica (Puntarenas and Bolson). It has been reported to occur in winter in Campeche and on Cozumel Island, Mexico, and casually or accidentally in Cuba (Habana), Jamaica, and St. Croix, Virgin Islands.