I've also heard you can wrap them in burlap or something similar and it might discourage them from coming back. When they find a tree they like that will get in a habit of coming to it often.
Sapsuckers seem to migrate through this area in large numbers this time of year. They also hit pines, and will kill a tree. I've only noticed damage at this time of year.
Yep - sapsucker. They have destroyed a cherry tree in my folks front yard. Some latex paint like was mentioned may be your only real hope.....or put some sort of window screen or the like up the trunk to the first branches and hope for the best.
When I pointed out this type of damage out to a forester, I was quite surprised to find out that it was caused by a bird! So, I used a tree tube cut lengthwise, wrapped it around the tree and hung it from the lowest branch, hoping that when the tree gets bigger, the birds will leave it alone. Still testing this theory out, but it seems to be working so far.