I had not watched that video before. For any "avoidance of doubt", flying that low over a flock of birds is a really bad idea. They will be have unpredictably when scared, and may turn into your path. I like to be in a place (altitude) where they could not reach, no matter what they do. I don't know about a Stearman, but hitting one of those in a light metal 'plane will 50/50 bring it down.
I once hit a seagull during approach. I jinked all over trying not to, but is was suicidal. I hit it on the hull, so no harm done, but still not good, it was a close call. Water landings often involve maneuvering relative to birds, but I avoid whenever I can. Sometimes a few scaring passes first will help.
This flying demonstrates risk taking, or poor judgement.