Reference article
Purple Swoop Duck’s Race
Purple Swoop Duck offers this race in Volcano.
Entering
Click the local rival and select a duck. There is no level requirement to enter.
Course
Jumping and climbing course. Ordinary races play automatically; trained skills and sufficient energy determine whether the duck reaches the finish.
Winning
Winning gives you 300 coins the first time you finish first. Once defeated, this rival no longer offers the race.
Progression
Winning supplies the orange key for 
Mystery Box.
Rival
This race is offered by 
Purple Swoop Duck.
Original Flash note
Some races give different coin rewards in the original Flash game.