[yor_on (OP)]

Saw it on the telly today, given as a fun fact?

(waiting for the doctor:)

Is it true? If so, why?

[alancalverd]

It's a lie.

[Bill S]

Alan is right.  Seems science agrees, as does my recollection of childhood experiences on a farm.

This is for those who might still doubt.

 http://www.acoustics.salford.ac.uk/acoustics_info/duck/

[chris]

It's incorrect. Trevor Cox did the experiment to prove that a duck's quack does echo about 15 years ago.

He explains it in the above link.

[yor_on (OP)]

Thanks a lot all. It sort of bugged me, and was the only thing worth remembering too :)
Watching that telly I mean

[chiralSPO]

Ironically, the claims made by quacks appear to reverberate through history, cropping up again every time the proof of their fallacy has faded from society's collective memory...