Place votives on some or all of the tables to give the room a romantic feel as the lights are dimmed throughout the evening. The candles will also be a nice touch for all the pictures taken. Scented candles are a nice option as well.
If you plan to use the traditional rice throwing for your ceremony conclusion, try using rice crispies, rose petals or bubbles instead.
Using these are a great idea and does not pose a risk to any birds.