In UK Brownies, the leader of a six is called a Sixer. A six is a small group within a Brownie unit, and the Sixer helps organise and guide the other Brownies in that group.
Each six traditionally has a deputy called the Second. The titles reflect the structure of the older scouting and guiding tradition, in which young members were given practical leadership responsibilities rather than leaving every task to an adult leader.
Sixes have often been named after fairies, such as Elves or Leprechauns, although many modern units use woodland animals or other themes. The Sixer may help with lines, games, ceremonies, communication and making sure the group works together.
Brownie units also have adult leaders. Brown Owl was the traditional title for the adult leader in charge, with other leaders sometimes named after different owls. That title is therefore a common mix-up, but it refers to an adult leader rather than the girl leading a six. Patrol Leader belongs more commonly to Guides, while Second is the deputy role.