A swan's landing is less a graceful descent than a carefully managed loss of speed. The bird approaches the water with its wings spread, then raises its body and changes the angle of its wings to increase aerodynamic drag. Speed falls. That matters for a bird whose weight makes an abrupt stop costly.
The wings do more than act as brakes. By adjusting their angle of attack, the swan trades some forward speed for lift, the aerodynamic force that helps support its weight as it descends. Too little speed can cause a stall, so the bird must balance slowing down against staying aloft. The margin is narrow. Wingbeats and changes in posture help it control the final approach, though the details vary with the bird and conditions.
The feet finish the job. Stretched forward with their webbing spread, they meet the surface before much of the body does; water resistance then helps slow the swan as its feet skim and push through the water. The drag can throw up spray, while the wings remain extended for balance and control. Wind and available open water also shape the approach: a headwind can reduce the bird's speed relative to the surface. Then the wings fold, and the disturbance spreads into rings.
