Sighting ghost

I was just out back and I saw a vague shape quickly glide across the wall of the shed at the back of my yard. and onto the roof of a shorter shed. It made a bit of a whoosh, and although it gave me the chills when I heard it in an otherwise very still New Orleans night, it made no sound of landing on the creaky corrugated shed roof. I started to believe I had seen the ghost of a cat lost in the storm, still chasing around its own neighborhood with the enhanced agility of the afterlife.

It turned out to be some sort of large duck, maybe a small pelican, as it flew away when I finally stood to go inside.

A neighborhood cat, a shaggy, white one was lurking to the other side of the shedtops.