Staff notation for the highland pipes is always written as if it were in D major, and, that being the case, the key signature is not usually indicated and may appear at first sight to be in C. This can be thoroughly confusing for the layman.

If you have actually got hold of a book of tunes in pipe notation, then a player can advise on how to transpose for other instruments. The cover illustration may just be generic, though. What is the title of the book? Who compiled it?