Are you serious? You cut one side so they fly in a circle and get tired is the biggest bunch of crap I have ever heard. If geese, swans or ducks are pinioned correctly then they cannot fly at all. They will get lift on one side and flip over every time. The exception are the whistling ducks because they have such a short, broad wing. I have many pinioned egyptian geese and there is one that was done incorrectly, has 3 of his primaries left and he can fly in a straight line for quite a distance. If he tries to turn then he loses lift and crashes, he does not fly around in circles. Tendon cutting, when done correctly, is an excellent method of de-flighting large birds that leaves them looking anatomically correct. Just remember that on the birds that require Federal Permits you still need to clip the right hind toe if they are not pinioned.