These Sha Ka Ruq avians are rarely seen, despite being daylight hunters.
It appears that these birds — a species of owl, the sages claim — have an uncanny, mystical ability to cloak their existence from their prey. However, this ability seems directed towards only a single prey animal. If a falcowl swooped into a flight of sparrows, only the target/victim sparrow would be unable to see or sense the falcowl — the rest of the group would flee instantly.
Due to this ability, falcowl feathers are sought out by alchemists and koldun for use in their experiments.
Travelers' Comments on Mystery Falcowls
I own a mystery falcowl as a pet. His name is "Sweetbeak." He is a good bird.
— "Baroness" Karlinda
I was once engaged to transport a hundredweight of falcowl feathers from Sha Ka Ruq to Crail. You have no idea how much volume such a small cargo weight takes up. Our hull was stuffed to bursting with feathers!
— Captain Froederik Wiki