Across
- 5. the voice organ in birds
- 6. keeping the eggs warm
- 8. Wings built for speed
- 10. the long trip many birds take to stay in warm areas
- 11. Wings good for lifting heavy objects
- 12. a flat bone that the wing muscles attach to
Down
- 1. Wings good for maneuvering in the trees
- 2. part of the respiratory system that enables birds to hold more oxygen, most have 6-9
- 3. thick walled and muscular part of the digestive tract that grinds food
- 4. Wings good for long distance flight
- 7. egg whites
- 9. an enlargement of the esophagus that stores food until it can move to the stomach