We have a tree peony which produces large blooms on an overall height of about four feet. This spring we noticed we lost about 1/4 of the woody stems, where new growth did not sprout. Those stems have small holes, with one branch about 12" long having 5-6 borer holes, spaced fairly evenly. The holes go right into the core of the stem. The hole is about 1/8", the area around each hole shows signs of damage or pecking.

Does anyone recognize this, and can tell me what is making these bore holes. Preventive measures ? Our yard has many birds, including small woodpeckers, but we never see them in this area of the yard. Ideas?

If it's woodpeckers, they could be after insects living within the trunk.
My tree peonies always lost some branches over the winter depending upon just how cold it got.
I would trim off the dead stuff and if it sprouts, try more frequent feedings.
I do see one reddish leaf bud down where the trunk splits into two. Everything from there up, to the left, looks dead.