I wonder too as I have had the ugly turkey buzzards circle my yard when the pups were out. I herd them back inside and don't take any chances. There were pictures of a hawk that took off with a dachshund on the news a couple of years ago and that was enough to scare me with any birds of prey!
The Turkey Vulture Society this says they will not eat live animals and are not a danger to pets or children.
Pesky Black Buzzards This says this type of buzzard will attack live animals.
Since I am not that good at deciding which bird I might be looking at inflight, I think I will continue being afraid of them all.