A quill is a writing implement made from a moulted flight feather (preferably a primary wing-feather) of a large bird. Quills were used for writing with ink before the invention of the dip pen, the metal-nibbed pen, the fountain pen, and, eventually, the ballpoint pen. The hand-cut goose quill is rarely used as a calligraphy tool because many papers are now derived from wood pulp and wear down the quill very quickly. However, it is still the tool of choice for a few scribes who noted that quills provide an unmatched sharp stroke as well as greater flexibility than a steel pen.

More Info: en.wikipedia.org