Most breed in area from US prairies to Yukon Terr. Some breed across E. Canada on small marshes, and a few broods have been counted in Maine. Heaviest migration routes are in Mississippi and Central flyways. Calif. A few will find suitable wintering spots along both coasts as far north as Alaska or Newfoundland. 5,000 to 13,000 harvested in Maine.
Nests are hard to find , located in dense, tall vegetation.
Greenwings prefer very shallow water or exposed mud flats to feed on seeds or mollusks. I am not aware of how to seperate them, and these are not distinguished in hunting regs. Bluewings concentrate their breeding range in US and Canadian prairie pothole region. We are on the very edge of their breeding range and a few broods have been counted in Maine. Bluewings have very complex southward fall migration.