What west-ward extension of the breeding range includes states like Missouri and southern Illinois?

Answer

The area west of the coastal plain, moving inland.

While the species heavily favors the coastal plain, the established breeding range extends significantly inland to the west during the warm months. This western reach encompasses states such as Missouri and southern Illinois, demonstrating that their summer territory is not strictly limited to the immediate coastal environments but pushes further into the interior of the eastern half of North America.

What west-ward extension of the breeding range includes states like Missouri and southern Illinois?
locationbirdvireoWhite-Eyed Vireo