Place raspberries, blackberries, strawberries, sugar and water in a saucepan. Stir.
Heat berries, sugar and water over medium heat until simmering, then lower heat to medium-low and cook for 10 minutes. Stir frequently with a fork. Mash berries with fork while cooking.
Remove pan from heat and allow the berry mixture to cool.
Pour berry mixture through a fine mesh sieve to remove any seeds, allowing juice to collect in a bowl.
Cover bowl and refrigerate until ready to make mimosas.
For each mimosa: Place 3 tablespoons wild berry juice in a champagne flute. Add 1 tablespoon Chambord. Fill flute with chilled champagne or sparkling wine.
Garnish with fresh raspberries and blackberries on a cocktail pick.
