Look at how pure the signal is from the peregrine's wings. The signal from feral pigeon is extremely noisy in comparison, as if it is fighting to stay the in the air. The peregrine wingbeat is clean so I presume the energy is being turned into velocity with high efficiency. Extremely cool.

I also love the longer clip with the bed of feathers: https://www.youtube.com/watch?v=d_FEaFgJyfA

It gives a good visual as to how much air is being moved/disturbed during the flight/glide of each.