HEDGE ACCENTOR (Prunella modularis)
This bird is more frequently known in English bird guides as a Dunnock, but in Europe is frequently translated as Hedge Accentor. This is more accurate as it is a member of the Accentor family and really does spend most of its time creeping around the bottom of hedges and bushes seeking tiny insects and small seeds. Even though it does eat small seeds it is not a finch and so the other English name of Hedge Sparrow is thoroughly misleading and should be forgotten immediately if you had not heard this before !
In Switzerland it is widespread but is most common in the montane and sub-alpine zones between 1000m - 2400m. The song is a rather loud, crystal clear set of high warbling notes uttered at high speed, usually from a high perch on the top of a pine tree:
It is delivered in short bursts and could perhaps be mistaken with the song of a Whitethroat or a more likely a Wren (which can be heard faintly in the background of that recording) but lacks the pattern and finishing trill of the Wren. Also Wrens sing close to the ground and are often hidden from view.
The very variable pattern of the warbling, with sudden changes of pitch, can be easily seen in the sonogram:
and perhaps easier to appreciate if it is slowed down to half-speed: