Runner Islands are live events that appear in the middle of your City. Tap it to enter.

Use Flight Stamps to go on a run, avoiding obstacles, collecting Pinwheels, and earning rewards along the way.
Collect as many Pinwheels as you can over the course of the event to reach bigger rewards. If you hit an obstacle, you can use Gems to revive yourself.

Flight Stamps are needed for each run. Obtain them by completing missions before the time expires, such as completing Quests, breeding dragons, collecting Food & Gold, winning League battles, or simply by purchasing them in the Shop.