A couple of observations on aquatic birds.
In flight, the Blue Heron allows its long legs to trail behind, horizontal, its feet folded one over the other, as a fine lady with elbow-length gloves might fold her hands. The feet look like the long, slender tailfeathers of a Tropicbird, and I wonder if they might not serve as a rudder.
The Canada Goose, on the other hand, at least when it is thinking of landing, splays its webbed feet and drops them down, toes back, so that they look like the flaps on a giant jet. The goose tilts its feet this way and that, adjusting its flight in minute increments until, just above the water, it shoves them forward, toes up, as landing gear.