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CHAPTER 17 III The Leg 177

the water’s surface (Figure 17-18). But the feet have
another important function during takeoff: to push the
bird’s torso off the water’s surface and greatly reduce
energy-robbing friction, enabling the wings to lift the
bird from the water. Once airborne and just like larger
commercial aircraft, the feet are retracted and stowed
beneath the undersurface of the torso or below the
outstretched tail.
When geese, pelicans, and cormorants land, they
use their feet initially as air brakes, letting them dangle
beneath their bodies as they begin to fl are (Figure
17-19). Just before touchdown, the feet are swung
forward, tips upward, much like a pair of water skis
immediately before the skier lands a jump (Figure
17-20). Again, like commercial airliners, some landings
are rougher than others, depending on the crosswinds
and the roughness of the water. On touchdown, wing
thrust is reversed and the feet are lowered into the
water where they can function in a coordinated pad-
dling fashion to advance, maintain position, or inde-
pendently turn and maneuver.

III THE VERSATILE PROPELLER:
PROPULSION ON AND BENEATH
THE WATER SURFACE

To most observers, the function of a water bird’s feet
Figure 17-16 • An Amazon parrot perches on the hand of a is clear: to propel it over the surface of the water (Figure
resident while being examined visually.
17-21) or to dive (Figure 17-22). But what is not so
readily apparent is how the feet of some water birds
are used when submerged, especially predatory water
all in the same action. The inward convergence of the birds in pursuit of prey (Figure 17-23). For example,
three backward-directed talons, combined with the the cormorant is an exceptionally skilled underwater
forward-directed base claw, provides a near-inescap- predator that uses its feet to both propel and guide
able, lethal grip that enables a raptor to carry away its itself while chasing down small fi sh. Specifi cally, the
prey in either one or both feet (Figure 17-17). cormorant’s feet can be angled horizontally to act as
During feeding, raptors often secure themselves stabilizers or vertically to function as rudders, enabling
on a branch with one set of talons, while gripping cormorants to change depth and direction almost
their prey with the other. The bird then feeds by instantaneously.
tearing away the flesh and entrails of its victim with

its beak.
Sandshoes
The webbed feet of shorebirds serve as broad, fl exible
III THE ROLE OF THE FEET IN platforms on which to negotiate the sandy shoreline
TAKEOFF AND LANDING and its contiguous shallows. In principle, a shorebird’s
feet function much like snowshoes, but unlike the rigid
During takeoff, most of the larger water birds, such as winter counterparts, a shorebird’s feet are quite fl exi-
geese, use both their wings and feet to become ble and are able to bend so as to contour irregular
airborne, with some, like the cormorant, requiring a surfaces such as gravel, rocks, and vegetation. Sand-
longer “runway” than others. Ducks can become air- shoes may also be conveniently collapsed during fl ight,
borne quite suddenly, especially if alarmed or startled, which results in improved aerodynamics.
appearing to almost leap into the air, a kind of
jump-start. Foot Injuries
When many water birds take off, they use their feet
in a manner that resembles running: initially getting The most common serious foot injuries encountered in
the bird underway and then rapidly accelerating over our practice are traumatic toe amputations, followed

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