These photos of a Gull-billed Tern were taken at one two thousandth of a second so fortunately there was plenty of light. I prefer flight shots with wings up. I feel they convey a greater dynamism but they are often marred by the shadow cast by the wing. If you click on the wing down shot the feather detail on the wing makes up to some extent for the less dynamic pose.
What you really need is a well trained Tern that will expose its armpit to the sun.
bobmcgee 