I don't have any water near to where I live but the Swifts , Swallows and House Martins do swoop in low over the fields out the back of mine and I love standing there trying to capture them in flight but with this dull lighting I don't stand much of a chance of getting any decent shots .
Thanks Mark. I use the D3 and the Nikon 70-200mm F2.8 VR. I've also used the Nikon 300mm F4 and the Sigma 50-500mm F4-6.3. I set the camera on spot and 2000/s shutter speed in manual mode. I miss the shot 1/3 of the time as the Swifts, House Martins and Swallows can change directions just by twisting their tail feathers. You need to watch them for a bit and wait until they come in close then quickly bring the camera viewfinder to your eye and try and focus as they fly by. A lot of the time you try to estimate in which direction they may go. You can practice without taking a shot until you get into automatic mode, just remember when you decide to take a shot, by the time you've press the button, they have moved a couple of foot further along.