In non-breeding plumage, males resemble the females, which are buffy overall, with dark stripes on their back, rump, sides, and head. Bobolinks nest in hayfields and meadows across the northern United States and southern Canada during the northern summer months of May through early July. They migrate to the vast grasslands of southwestern Brazil, Paraguay, and northern Argentina to spend the austral spring and summer months of November through March. Relatively small numbers may winter along the coast of Peru and Chile. By traveling to temperate latitudes on either side of the equator, Bobolinks have what warm weather lovers might call the best of both hemispheres.
Bobolinks migrate at night.
Bobolinks begin their journey northward in South America in early March, reaching Colombia and Venezuela in late April. From there, most take a route over the Caribbean Sea to the Florida peninsula, although some will cross the Gulf of Mexico from the Yucatan Peninsula to Louisiana and Texas. May. One of the most interesting features of the Bobolink's breeding behavior is the tendency for some males to form a pair bond with more than one female in a single nesting season. Polygynous males are most likely to be older, more experienced males that can lay claim to the best territories. They devote most of their time and attention to the first mate of the season and their young, assisting with the feeding and defense of young at other mates' nests only as time and resources permit.