The number of birds of a species or group that can be harvested in a day is defined as the daily bag limit. Traditionally, bag limits have been large for birds that are highly productive, very abundant, short-lived, or lightly hunted. Flyway differences exist, with daily bag limit being most liberal in the Pacific Flyway and most restrictive in the Atlantic Flyway, for the same reasons that the season lengths differ. Shooting hours limit the time of day when migratory birds may be harvested, and have rarely been changed except when hunting seasons have become very restrictive. Since 1918, one-half hour before sunrise to sunset has been the traditional shooting hours.
Special regulations consist of framework regulations that are applied on a small scale.
These consist of split seasons, zones, and special seasons. States have been allowed to divide their hunting period for most species and groups of birds into 2 or sometimes 3 nonconsecutive segments in order to take advantage of species-specific peaks of abundance. Generally, special seasons focus on those species considered to be more lightly utilized than others. Special seasons are usually, but not always, in addition to the regular season. Special seasons currently exist for some teal, wood duck, sea duck, and resident Canada goose populations.