Ravens are larger than a Good sized Brahma Rooster........I also have Magpies and Crows that chase the Ravens away....The Crows have migrated but the Magpies are still here all year......I do not know Buzzards.....They are further South.....Ravens must be the size of Buzzards then we have huge buzzards here thankfully they just clean up dead animals. Our biggest threats are hawks we have them year round.
Cheers!