Heat a griddle or two large nonstick skillets over medium-low heat. Heat oven to 200 degrees F.
In a bowl, whisk flour, cornmeal, sugar, baking soda and salt until blended. Make a well in the center. Whisk buttermilk, egg and oil in a bowl; add to flour mixture. Gently whisk just until moistened. Fold in blueberries.
Using a ladle, drop batter in scant 1/3-cup rounds onto hot griddle. Let cook 2 to 3 minutes until edge is firm and bubbles form. Carefully flip over and cook an additional 2 minutes. Keep pancakes warm on a cookie sheet in 200 degrees F oven.
Repeat with remaining batter. Serve with butter and maple syrup, if desired.