Cornell has an enhanced extract from the 1956 William L. Rhein Imperial Woodpecker film. The extract was included in the supporting materials for the Auk paper that discusses the film. I had overlooked it until now and suspect that others may have missed it.
In this clip, the bird can be seen scaling bark from what looks like a living pine. While the quality of the film is poor, even with the enhancement, the upper section of the scaled area shows signs of earlier excavation. The bark chips removed in this segment appear to be fairly small, especially when compared to some of the larger one’s we’ve found, but the speed and efficiency with which the bird removed the bark, as well as the way in which she did so, may be relevant to the scaling we’re seeing in Lousiaiana.