Drumming (snipe)

Drumming (also called bleating or winnowing) is a sound produced by snipe as part of their courtship display flights.

[1] The sound is produced mechanically (rather than vocally) by the vibration of the outer tail feathers when flying in a downwards, swooping motion.

The first of many was conducted in the year 1830 by a German scientist Johann Friedrich Naumann who proposed that the sound was being produced by the wings.

[2][4] A few years later after reading Naumann's proposal, the scientist Friedrich Wilhelm Meves conducted studies that looked in-depth at the tail-feathers of snipe.

These display flights are performed by both sexes in threat contexts as well and appear to be antagonistic in their action, even when directed by males to females.

Like during the migration periods, drumming as a territorial display occurs sporadically at any point in the year, though it is most intense on the breeding grounds.

[9] In order for the drumming sound to be produced, the snipe must reach a velocity of 25 mph (40 km/h) which is required to start the vibration of the outer tail-feathers.

In bending this way, along with the twisting of the outer tail-feathers, the length of the vibration is continuous as long as the required air speed is maintained.

There have been differences noted between both the outer and inner tail-feathers of the snipe to help better explain the aerodynamic mechanisms that are responsible for its sound production.

[2] The quivering of the wings interrupts the flow of air to the tail-feathers during a dive and actually decreases the vibration, which is what allows for the shaky and tremulous quality of the drumming sound.

The true snipes comprise nine species, all of which are quite similar to one another, however, they differ mainly in terms of both the size and number of their outer tail-feathers.

[11] Some characteristic traits of their appearance include having a black-striped crown, light-coloured spots that form 4 lines running down their back, and a russet tail.

Johann Friedrich Naumann was one of the many scientists interested in this task and he proposed that the drumming sound was mechanically produced by the wings.

Throughout many years of testing various experiments in order to explain exactly how the mechanics of the drumming sound of snipe is produced, Arnold B. Erickson made the concluding statement in 1953 that affirms that the sound is "produced primarily by air vibrating the still outer tail-feathers as the bird spreads them while going into a power dive.

The tremulous quality of the sound is an effect of the slow quivering of the wings superimposed on the more rapid vibrations of the tail-feathers".