Fairies have their own weak form of magic, which they use primarily to avoid being eaten by predators. According to Scamander, fairies are held to have very limited intelligence, and they do not use any form of language that humans understand (but see languages) (FB).
References from the canon
The type of magic most often associated with fairies is the ability to produce light. Professor Flitwick used fairies as living "lights" on a Christmas tree in Harry's Third Year (PA10). Fairies were also used as decorations in the Hogwarts Rose Garden during the Yule Ball (GF23).
Fairy wings are also used as in the Beautification Potion as an ingredient (Pm).
Fairies are common in folklore the world over, usually depicted as small ethereal beings which live out of sight of humans, often in woodlands. Fairies have magical powers to fly, cast spells, and predict the future. They can be friendly but are sometimes depicted as mischievous or even malevolent. Ms. Rowling’s version of fairies is quite different from the traditional type, more like insects than intelligent nature spirits. (The Lexicon page 109).
Tags: fairy tales