Male Redstart. The Redstarts are common nesting warblers in S.E. Minnesota. About 25+ species of warblers pass through Fillmore County on their way north from the American Sub-tropics to nest in the upper midwest and Canada each year. Some nest here, but most continue farther north to nest. The warblers are small, and in general very colorful family of birds. Most pass through from about May 1 to May 30th each year. We look forward to seeing them each year, but this May has been cold and wet, and the warbler migration thus far has been slow with small numbers of birds. They are declining in numbers as their woodland habitat in both North and Central America is in decline.