Repeat Recording of the Shrew?

As an old geezer, I am always faintly amused at how research tends to recycle. This is especially so, it seems when the original material was in print, before we got heavily into electronic media ('old stuff' seems to simply 'fall off the conveyer belt'). I caught part of a piece on BBC Radio 4, where an ornithologist ('bird man'), was describing how he was using a bat detector (this is a device that converts the ultrasonic calls of bats, that have too high a frequency to be picked up by the human ear, into audible sound), to study the cries of wild mammals, like the Common and the Pygmy shrew. It's interesting stuff (the sounds were impressive) and it was evident that you can learn much about the identity and social interactions of wild rodents by 'breaking into' these 'private' frequencies. I was immediately reminded, however, of long-retired Dr Gill Sales, who spent her whole career at King's College, London studying rodent ultrasounds with bat detector-style equipment. She investigated (and published extensively) on the communications used by neonatal (new born) and adult rodents. Gill carried out work on wild as well as laboratory rodents. What goes around, comes around!