Different seasons among flyways and regions recognizes differences in migration patterns and hunter activity.
States often use specific regulations to manage waterfowl harvest and hunter numbers.
In Minnesota the DNR has the task of balancing harvest by the largest number of waterfowl hunters in the nation and protecting the breeding population of resident waterfowl. The combination of time and place regulations have been used as tools to manage duck harvest since the early 1900's. The earliest private use of a combination of regulations can be traced to the historic Heron Lake agreement of 1906. The intent was to extend opportunity for all throughout the season and is still in effect today. Bellrose reported in 1944 that the most important disturbance and the one that caused ducks to avoid or leave an area was shooting in the predawn or late-afternoon darkness.