Breeding ospreys are known to travel as far as 14 km from their nest during hunting forays. Non-breeding individuals are known to travel as far as 10 km between their daytime feeding grounds and their roosts.
They vigorously defend their nests or nest sites from intruders. This is most likely because nests are used by the same pair for many years, and represent a significant investment of time and energy by that pair.
Canon 50D, EF70-300mm f/4-5.6 IS USM