Invasion of the Turkey Vultures

I got up in the morning, heard flopping noises outside.   On top of the 50-foot tree, there is this huge turkey vulture spreading its wing.

There are more than one to make so much flopping noise, here is another one.  

Under the one with wing-spread, another one on the branch.

At the top of a redwood, another turkey vulture.

One on our antenna!

Another big one.   What's going on?   No clue.  Turkey vultures are known to prefer recently dead animals, but we don't have any dead animals in our yard.  It's really uncomfortable to see them perching on our trees.   I tried banging on trash cans, turning on leaf blower, yelling at them, ... nothing worked.  I had to leave home for an appointment, worried.   I rushed back after the appointment in about 2 hours, thank goodness, they were gone.  Nothing harmed, not the vulture, not the rabbits.