Combine first 4 ingredients in a medium-sized bowl, stirring with a whisk. Lightly spoon flour into dry measuring cup, level with a knife. Combine flours, baking powder and salt in a large bowl, stirring with a whisk.
Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Gently fold in blueberries. Add milk mixture, stirring just until moist (dough will be sticky).
Turn dough out onto a floured surface, pat dough into an 8-inch circle. Resist temptation to knead the dough; doing so would break apart the tender blueberries. Cut dough into 10 wedges, and place the dough wedges on a baking sheet coated with cooking spray.
Bake scones at 375 degrees for 18 minutes or until golden. Serve warm.
Makes 10 servings. Leftover scones are nice with tea later in the day.
Make scones a day or two ahead, and store in an airtight container