Citat:
Orient to path direction.
If say, your motion guide was a circle, you would have the bird fly in a thrilling loop.
However it would look kind of odd, since the bird would only follow the circle, but not
actually point the nose in the direction of the circle.
During the entire loop the bird would have its head pointing to the right
Eventually the bird would fly backwards. Quite a thrill maybe... but .. not too realistic
If you want the bird to actually follow the circle, not only in movement, but also in direction,
you should double click the keyframe in frame 1 on layer 1.
This will reopen the frame properties box.
Choose the "tweening" option.
Select the "Orient to path direction" option, and click ok.