I had thought that our local woodpeckers sought water up on poles like this but this particular bird drew my attention with the classic beak-tapping we all associate with woodpeckers - Except it was ringing off the metal as it would like some sort of alarm bell going off. I am amazed it didn't feel the difference between wood and metal and wondered why it continued to strike the metal in this fashion, but it continued ringing out as I stopped for some photos and then went on by.