About the Romans and Etruscans?

The Etruscans (also known as the Tuscans by the Romans) held birds in high esteem. It is believed that the Roman use of the Eagle as a Symbol of State came from the Etruscans.

Communication from Deities was usually done through birds and to a lesser extent berries. This was often depicted in their art.

Etruscans were very concerned about divination and read the presages in thunder, bird's flight and liver of sacrificed animals. Romans relied on them for such things (apart of learning most of their technology from them). Those birds surely represent favorable or nefastous presages, I guess.

If I don't recall badly, birds coming from the left were nefarious presages (hence sinister, from sinistra, left) and those coming from the right were favorable.