Around our property we have nesting pileated wood-peckers (large prehistoric"woody woodpecker" looking things). If the lines are in a straight alignment the wood fibers of the pole will do a pretty good job of keeping things up as the size is about 200% of what's needed. The wood pecker hole only uses about 15 to 20% of the cross section of the pole and really does not pose a problem. Problems occur after several years of nesting use, it stats rotting from the inside out. Now, if it's a guyed pole or has a transformer or drop to a house there could be some strain that as above the power company monitors.
Here we have several snags and a couple power poles that have nesting cavities. The little acorn type birds don't seem to nest in the poles, rather they jamb acorns in cracks to save for when the bugs inside get large and they return to eat them.
The power company was replacing poles and I caught the guys at lunch and asked them about the nesting birds. I asked if they were going to work around the nest and they explained they install the new pole adjacent and top the old pole off below the cross arms and above the nest. They retrieved the old pole a couple months later when the birds fledged.The people doing the work said they have biologists and know they have to protect the nests.
The land owner where the nesting occurs (and the poles were located) is a good steward and leaves a few good sized snags as wildlife trees for the birds use. Even with that sometimes they use the few power poles in the area for some reason.
idk what kind wood peckers you have, but here, pileated are considered keystone habitat modifier and are a protected species. Pileated iirc are the only that create the large hollows in trees out west.