The "sticks" protruding from some of them look like they may be piers for small boats (canoes, rowboats, etc.) A couple of the islands appear to have small buildings on them. But the odd color (colour) of the "islands" escapes me. Maybe they are man-made, or just possibly devoid of vegetation? The pond itself looks like it would be a great fishing hole as a river both feeding it and discharging from it. Only the uppermost "island" seems to have vegetation. My guess is that they are man-made islands with piers, and a couple with small buildings (cabins if you will) for remaining there. But hey, I could be wrong altogether!