From Garbardito in the Hecho Valley of the Spanish Pyrenees I was able to record one or two Wallcreepers. It has glissando whistles and other short songs, both of which are on this recording. The sonogram has two of the songs shown. Click it to hear. The rising whistle shown is the second whistle followed by the short song at 7 seconds. Some time has been edited out from between late songs in sequence.