C.W.
I have found the earlier I put them to bed, the later they sleep (odd- but sometimes putting my son to bed at 630-645 will yield at 7am wakeup, but putting him to bed at 7P-730P will get me a 530A wakeup). I have also found an environmental factor contributing to early spring wakeups--usually very loud birds or garbage trucks, so you may want to listen one morning at what is going on outside. I will usually ignore the wake up until 630-7A when I will get up. Sometimes he doesn't go back to sleep, but a lot of times he does. Both of my kids were very late giving up their morning naps, just before age 2, so I don't know if this will help you.