Preheat oven to 350 degrees. Spread coconut on a rimmed baking sheet; bake until light brown, 8 to 10 minutes, rotating pan once. Set aside to cool.
Lightly frost cupcakes with 1 cup chocolate buttercream; set aside. Tint 2 tablespoons reserved buttercream pale yellow; place in a pastry bag fitted with a #349 Ateco leaf tip; set aside. Tint remaining buttercream light blue; place in a pastry bag fitted with a #11 Ateco plain round tip, and pipe three bluebird heads, 3/4 inch in diameter, onto each cupcake. Using leaf tip, pipe yellow beaks. With a toothpick, add melted-chocolate eyes. Form each nest with 2 tablespoons toasted coconut.