Hummer myth or misunderstanding

Just recently, I read of a scientific breakdown of Anna’s hummingbird creating a sharp, loud chirp. This was just after I heard the sound, from inside the house, of the chirp. The scientist     did an extensive study of the hummer in a wind tunnel and with high speed photography. His conclusion was that the bird produced the sound with the tail feathers, as the bird was flying at 50 miles per hour. Here is the rub. While outside and near, about 15 feet from a hummer, the bird chirped and very loudly. The bird was perched! A bird perched is not moving at 50 miles per hour! I am not qualified to determine how the bird produced the loud sound. 

The take away; You can ask a biologist or a ornithologist a question, and you will receive an answer, sometimes promptly, but don’t you dare suggest that the scientist is wrong in his discipline. NB.