Divining the future from the study of birds -- either through watching their movements or through listening to their calls (song, crowing, etc). This is the root of the word auspice. The ancient Romans use to do this, in special areas called templum*. These were imaginary divisions and lines in the air, and where a bird moved through them was VERY VERY important.
A synonym with augury. Both were practiced by augurs.
* It should be noted that the same word was used for temples. I think the augers might have been giving themselves airs.