Adorable shot!
Too bad you only used 510 of the allowable 640px. I would have loved to see this at a larger size.
Couple things: your crop is a bit tight and focus is too soft IMO.
I generally hate duck and swan pictures, but this one is really quite nice. Very nicely framed. Nice composition. I think it is really nice how the little guys are in swimming in the reflections of the parent. It's a very peaceful image; one that would hang very nicely in a doctor's office, or any office for that matter. <7>
Cute pic of the cygnets. Crop is a little tight on the top - feels like the right hand swan is a little cramped for space. Very nice reflections and colors.