Question
i have found  rows of holes around the trunk and some branches on my 2 bradford pears    havent seen a woodpecker  and was wondering what may be the cause?   g

Answer
It sounds like a woodpecker called a sap sucker. These birds make the holes in the bark and sap will form in the holes. Small insects come to feed on the sap and the bird returns to eat the insects. These holes cause not problem with the tree. Most of the time you will not see the birds.