Nice action series. Birds that have both white and darker coloration are tricky exposures. In such bright light some exposure compensation dialed in will help and you'll gain a bit of shutter speed as a result. Certainly correcting exposure will be a priority and may simply be a case of changing your metering mode, assuming you are shooting in AV or TV. Your compositions are very nice but I would suggest a counter-clockwise rotation on the first series to level out the water, provided you have the image available to do so to your satisfaction.
You did great for having less glass than you wanted, looking forward to seeing your work with the 400.
