Hi John,
In Germany, bird populations are tracked by map squares of ca. 130 km^2 , and in well-suited regions, one of these squares is home to up to 8 breeding pairs of Sea Eagles.
It looks like the Isle of Wight is about three map squares in size, and not so different topographically from the East of Schleswig-Holstein where four pairs of Sea Eagle "held the fort" during the 1970s' population minimum.
As juvenile Sea Eagles have been observed up to 1000 km away from their hatching sites, I don't think the Isle of Wight would necessarily be isolated from other populations either.
Regards,
Henning
I don't know how heavily populated the East of Schleswig-Holstein is, but the Isle of Wight is part of the South Coast playground of Britain. In summer (breeding season) it is rammed with screaming holidaymakers, many of whom spill over onto the seas round about - full beaches, inshore waters with kite surfers, wind surfers, dinghy sailors, yachts, jet-skis, speed boats, anglers.... who did I forget?
On shore the island is full of ramblers, dog walkers, cyclists and people attending and moving between a thousand attractions built to pull them in. There is not much quiet space. How tolerant of noisy humans are breeding White-tailed Eagles?
While I take your point about movement of juvenile White-tailed Eagles I'd like to point out that the other side of that coin is that the last couple of them that travelled to Hampshire did so for their first winter and then disappeared off, presumably back whence they came, in one case that being known to be Finland. So how far they move in their youth is not necessarily indicative of the likelihood of them joining or founding a local population.
What we haven't had in Hampshire is a continuous stream of Scottish first-winter White-tailed Eagles checking out the big island, either temporarily or permanently. So a few birds on the Isle of Wight are likely to be isolated from Scotland, let alone Central/Eastern/Northern Europe.
So far as persecution goes I think it is fairly light in Hampshire and round about: we've plenty of Buzzards, the Kites are going from strength to strength, Goshawks do well in the New Forest - but we're not exactly over-run with them up here in NE Hampshire yet..... Peregrines we do have but half of them breed and roost in towns where shotgun-toting gamekeepers are rarely seen, so that may not be much of a guide to what happens to really predatory raptors in rural areas. Hopefully it would be OK.
John