From the sign at the parking lot, walk 40 m until you are in front of the bridge over the river and a picnic table is on your right. Go to the old, giant willow tree which is just to the right of the picnic table.
Bridge & Picnic Table 
Willow Tree
Step into a duck’s world as you search for 4 clues to a mystery: the black duck’s secret of survival. Discover the clues throughout the trail and then unscramble the letters in the boxes at the end to figure out the secret word. Along the way you’ll have to care for and protect your own duck eggs. Are there hungry duck predators around?
You’ll have to do some spying too as ducks aren’t about to give away their secrets.
To gain the power you need to solve the mystery, touch the ancient willow tree, which is the Guardian of the Marsh, and say…
“Ancient Willow,
Giant tower
To be a duck and solve the mystery,
Give me power!”
Act and sound like a duck and you’ll blend in better. Do the duck waddle walk as you quack down the trail.
You can install Earth Adventures as an app for easy access and offline use.
and then "Add to Homescreen".