might have been this boot. While it is on the banks of the Mississippi River, it's not an Ivory Gull
This is also not an Ivory Gull though it has a white head.
These birds could be Ivory Gulls. They're all white.
However they can't #$%^# fly, so by definition they can't be Ivory Gulls. The Ivory Gull flew away. Two &%%^@ days ago.
I guess we were close to St Louis, because similar to Ivory Gulls, these didn't use to regularly grace the banks of the beautiful Mississippi River.