Pianoscope's pitch detection is currently not limited at the upper end of the scale. The reasoning behind this is that you might be pulling a C8 too high and want to know that you now ended up on a C#8 or D8. An ambient chirping bird can easily trigger such a high note so that pianoscope reacts to it. As these high piano notes barely have more than a single partial, it is hard to discern them from background chirps.
Is this behaviour causing any problem for you?
