WREN (Troglodytes troglodytes)
The Wren is one of the most widespread species in Switzerland, usually breeding where there is dense undergrowth it is most common at about 600m, but it can be found as high as 2,600m, usually in montane scrub at that altitude or perhaps around rocks and stone walls. This is a tiny but very energetic bird, I think of this as a bird with "attitude". For its size it makes a tremendous noise when it sings - cocking its tail up, throwing its head back, it puts its all and everything into a song which is a high-pitched rapid trill:
It is hard to follow by ear so have a look at the sonogram:
It is a series of repeated rapid trills of different patterns lasting about 5 seconds. People have reported local dialects in wrens and the trills can be variable in pattern. One common element seems to be the rapid clicking followed by a trill that are the last two phrases of the above.
I agree it is hard to distinguish it all - so here it is again at one-third normal speed - since it is slowed down the pitch (frequency) is also lowered so it sounds weird, but it is easier to undertand the pattern this way (give it a minute to load as it is a big file):
The Wren also gives a very strident alarm call - a series of loud chacks which run together into a chattering sound, but when I look through my archives I realise I need to get better recordings of this before posting - it'll come soon I hope !!