These warblers are tiny endurance champions, making the longest migration of any North American warbler! They are one species that does loop migration. In the spring, the Blackpolls return from their wintering grounds in Puerto Rico, the Lesser Antilles, or northern South America by crossing the Gulf of Mexico or the Caribbean and continuing their migration over land.

In the fall, Blackpolls take off from New England and fly over the Atlantic to northeastern South America. Their fall route averages 3,000 km (1,864 mi) over water, and could mean a nonstop flight lasting up to 88 hours!