The Preen gland, also called Uropygial gland empties to the skin surface through a nipplelike pore at the base of the tail.
Osprey preen by rubbing their bill and head over the preen gland pore and then rubbing the accumulated oil over the feathers of their body, wings and skin of the legs and feet.
The oily, waxy substance helps waterproof feathers and keep them flexible.
About Harriett Raptor
Eight-year-old mother of five, fluent in telepathy, a possessor of genetic memory, a genius and scholar. Harriett holds the equivalent of a PhD in philosophy, biology, chemistry, physics, astronomy, and the Homo sapiens’ concept of the humanities. Her understanding of mathematics and logic are beyond Homo sapiens’ current comprehension. Harriett is a thinker, a wise osprey, especially distinguished for her expertise in the Homo sapiens problem.
Osprey Tales 
I can’t get your camera #2 to work today.Thank you keep up the good work . love it Jan
“Wow, it’s so nice to hear you Jan.”
oops ti’s working now
“Thank you,” said Harriett. “The doctor needs to know when things are not working.”