In The Fortunes of War, Doctor Maturin hoped to see a skimmer (Rynchops niger, aver. length 16-20 in., aver. wingspread 42-50 in.). Here it is. They are the only bird with a longer lower bill then upper bill. They skim down over the water with the longer lower half of the bill shallowly cutting the water. When the bill strikes a small crustacean or fish, the skimmer clamps down the upper part of the bill tightly. As the upper mandible closes on its prey, the skimmer moves it head backwards and downward, then without changing it steady flight drags the bill from the water and swallows its prey. It then lowers its bill into the water to continue fishing in flight. You can understand why the Doctor wanted to see the amazing performance.