A: Transitions are difficult for toddlers. It is not unusual that children of 2 1/2 have tantrums when it is time to stop one activity and begin another, or leave one setting and enter another, or say good-bye to one parent and go home with the other. On the basis of limited information here, it is hard to know what is upsetting your son and therefore hard to know how to fix it. It is possible that he has had a good time with his father and is all tired out--or some similar everyday explanation. He may be hungry or too keyed up by an exciting game. He may feel interrupted or uprooted. There may not be any particular reason.
It is possible that your son has picked up on some unfinished tensions between you and his father--whatever the issues were that needed a court to resolve. Little children can be very sensitive to these emotional vibrations. It will be good for your son for his father to play a genuine role in his life, as he is now doing; but to make the most of his father's involvement, it is best that you and his father can work together as a team. If you think that you and his father are not communicating well, you might suggest that you try to talk things out together so that you can present a unified partnership as parents. Sometimes the addition of a third party such as a counselor or member of the clergy can be helpful in ironing out these issues through discussion.
Meanwhile, you can try to minimize the difficulties when you pick up your son by trying to make the transition as slow and smooth as possible. Try to be calm and friendly. Stay for five or ten minutes so that your son sees the two of you together without a rush. See if you can distract your son with something he likes to eat or a toy to examine as you guide him out the door. Reassure your son that he will be back to see Dad very soon. Perhaps Dad can give your son a little overnight bag or some sort of special reminder to hang onto to help him understand that he will return before long.
Elizabeth Berger MD Child Psychiatrist and author of "Raising Kids with Character"