Blackpoll warblers that breed in western North America may migrate up to 12,400 miles roundtrip each year, some crossing the entire North American continent before making a nonstop trans-ocean flight of up to four days to South America. Now a new study led by first author Bill DeLuca at the University of Massachusetts Amherst and project lead Ryan Norris at the University of Guelph, Ontario offers details of the feat.