thanks so much everybody.
these swans are actually at a large lake park on the edge of downtown orlando. it's quite amusing really. i've been to a number of parks, gardens, and wildlife areas around here... but no other place offers the opportunity to consistently get so close to so many animals as lake eola. the squirrels, ducks, and swans are all so accustomed to people (and to being fed by people) that they're not too skittish. the mute swans are the most fickle of the bunch, usually leaving immediately if they don't see food, so i was pleasantly surprised when three of them hung around grooming themselves for a few minutes while i sat nearly at arm's length just watching them and taking pictures. the ducks, on the other hand, will actually run up to you asking for food... and the squirrels will also end up within arm's length if you just sit still in the grass for a couple minutes. they are brave and curious. there are black swans too which seem to just wander around the park all day in pairs.
i did have some really nasty purple fringing in high contrast reflections shooting wider then f/2.8 (in fact you can see some at the bottom of the bubbles being blown by the swan in #2), but that's probably to be expected. all in all, i'm extremely happy with my decision to pick up this lens.