Black Woodpeckers in action

I went up to the beech and oak wood above Budapest where there are a few pairs of Black Woodpecker. I have been watching these birds, and their ancestors, for many years now. So far this year I have not been able to find the nest hole of one pair as the undergrowth has really shot up. Usually the birds nest in one of the large beech trees in a clearing, but the scrub in that clearing is getting higher and thicker and it is hard to get through it. The birds are there alright, doing everything they do in spring, drumming, calling, flying about, but I just cannot get to the trees where I think the hole is.