Oh, someone here told us it was good luck if an Osprey likes your boat. Another fellow related his story of having the Osprey adopt his boat and his loving having the bird there because it kept all the other birds away. Further, the Osprey's poo was missing his deck (for whatever reason). In our case, we've had birds of prey enjoy the top of our mainmast a few times. The evidence is always little bits of other birds on the deck (gross!). There's nothing like cleaning bird feet and bird feathers and other "stuff" off the deck in the mornings