How do birds fine-tune their wing-shape?
AWing-shape determines the type of flight to which a bird is best suited. The short wings of robins are great for manoeuvrability, for instance, while the tapered wings of swifts allow for speed. Most birds can make some adjustments by flexing the wrist (a wing joint) or altering the angle of the hand bones (at the end of the wing).
Extreme wing shapes come with limitations. Short wings must be flapped rapidly to maintain lift, while very long ones make take-off tricky. Some species, such as red kites, try to have it all, sporting long-ish wings with slotted tips for both efficiency and fine control – the position of the primary feathers can be adjusted to catch or spill air.
The long, plank-like wings of the wandering albatross enable it to soar for long distances, saving energy.