After some general remarks upon the constant flight characteristics of birds belonging to any given species, the author describes his method of obtaining, approximately, a cinematographic reproduction of three geometrical projections of the wing-beat. Dealing with one particular case he determines the trajectory in space of a pigeon's wing tip during an entire beat, and, also, the speed and acceleration reached by it.
Note on page No 458 * GUIDI: A Study of the Wing-beats of Pigeons in Flight: AEROTECNICA, Aug. 1938, translated in R.Ae.S. Journal, December, 1938.