Percussion section

The percussion section is one of the main divisions of the orchestra and the concert band. It includes most percussion instruments and all unpitched instruments.
The percussion section is itself divided into three subsections:
These three subsections reflect the three main skill areas that a percussionist studies.
Percussion sections, consisting of similar instruments, may also be found in stage bands and other musical ensembles.
Tuned percussion.
This subsection is traditionally called tuned percussion, however the corresponding term "untuned percussion" is avoided in modern organology in favour of the term "unpitched percussion", so the instruments of this subsection are similarly termed "pitched percussion". All instruments of this subsection are pitched, and with the exception of the timpani, all pitched instruments of the percussion section are in this subsection.
They include:
Despite the name, "keyboard percussion" instruments do not have keyboards as such. Keyboard instruments such as the celesta and keyboard glockenspiel are not included in the percussion section owing to the very different skills required to play them, but instead are grouped in the keyboard section with instruments that require similar skills.
Auxiliary percussion.
All unpitched percussion instruments are grouped into the auxiliary percussion subsection, which includes an enormous variety of instruments, including drums, cymbals, bells, shakers, whistles and even found objects.
Players are expected to be accomplished on the snare drum, bass drum, clash cymbals and other hand percussion, and to be able to adapt these skills to playing other instruments and even objects, for example the typewriter.
Timpani.
The timpanist is a specialist who does not usually perform on the other percussion instruments during a concert. A high level of skill unique to this instrument is expected. While players of the keyboard and auxiliary percussion subsections often play many instruments from both subsections during a performance or piece, the timpanist is normally dedicated to that instrument.