The Bobolink population is at risk due to habitat loss. Their North American population declined up to 65% between 1966 and 2015. In Pennsylvania the bird’s population is stable but dependent on continued available habitat. A pair of Bobolinks needs a minimum of 5-10 acres of habitat to nest. But a larger contiguous area attracts a higher density of nesting pairs. Bobolinks nest on the ground in hay and fallow fields, meadows, and tall grass prairie. Most clutches contain five or six eggs.
In Pennsylvania bobolinks nest most successfully in the northwest and northeast on farmland at high elevations where cool spring and early summer temperatures push back hay growth and delay cutting until after broods have fledged.
Most Bobolinks winter east of the Andes in the grasslands, marshes, and on rice cropland of southwestern Brazil, Paraguay, northern Argentina, and central Bolivia, traveling approximately 12,000 miles round-trip each year.