Complex sentence: The peregrine falcon hunts most often at dawn and dusk, when prey are most active, but also nocturnally in cities, particularly during migration periods when hunting at night may become prevalent.
Split into simpler sentences: The peregrine falcon hunts most often at dawn and dusk, when prey are most active. Peregrine falcons are nocturnal.But also nocturnally in cities, particularly during migration periods when hunting at night may become prevalent.