For most callers or dog hutners the day is by far the most successful. You can cover more country easier, see the animals further or at the very least see them moving. You can also learn more form their actions in coming into a call, which is really important for further calling.
During the winter when it's real cold all day long is good as well, towards the end of the hunting season, it gets a bit more complicated due to the mating and paring up.
Night calling is clearly geared to those who already know the area and how to approach and set up to call, not many are going to just wing it and be very productive.