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Fastest running
bird
By Nutan Shukla
A DESERT bird of the American
south-west is the worlds fastest-running flying
bird. It rarely flies, but is nimble on the ground. With
large X-shaped claws and strong legs, it can speed up to
24 km an hour. It has been clocked at 42 km an hour when
chased by a car. It runs, almost arrogantly, with a
straight neck, its wings slightly open as stabilisers,
its legs going at 12 steps a second and its tail is used
as a rudder that can turn the bird through 90 degrees
without slowing down. By flicking its foot-long tail to
one side, it can turn in mid-stride. When it is spread
and raised above the birds back, the tail can help
brake the bird to a quick halt.
Birds that live in the
desert feed on a variety of things, from seeds and
insects to snakes. The roadrunner, a clownish-looking
bird belongs to the cuckoo family. It is non-brood
parasitic, runs on the ground more than it flies. It is a
great snake catcher and prefers to pursue its prey, which
include lizards and invertebrates apart from fast moving
snakes, on the ground. Once it kills its prey, it starts
to swallow it. Often the snake is too long for the bird
to get down all at once. Many roadrunners have been seen
walking around for a whole day with a snake hanging out
of their beak. It is swallowed inch by inch, as the lower
end is digested.
Roadrunners
have the most unusual physiology. Despite being a bird,
it is, to some extent, a cold-blooded creature. During
desert nights when the atmospheric temperature becomes
very low, most birds increase their metabolism to
maintain a constant temperature. For this, they have to
burn their precious energy reserves. The roadrunner
counters this problem by allowing the body temperature to
fall slightly. This means it allows its body to save on
the costs of central heating by not burning
the energy reserves. In the process of allowing the body
temperature to fall, the bird becomes torpid (sluggish).
The bird, thus, may be slow to respond to danger but the
species has few predators. The slight disadvantage
appears to be fairly unimportant.
Also very unusual is the
way in which the semi-torpid roadrunner warms up in the
morning. On the skin of its back, just between the wings,
it has special darkly pigmented areas which absorb the
suns energy more quickly, warming the skin and
underlying blood vessels. The bird also fluffs up the
feathers covering the patches so that the process is
hastened. Without this mechanism, the roadrunner would
use up to 50 per cent more energy in reaching a working
temperature.
To enable its chick to
have a regular dose of water, this bird has adopted a
novel way. It holds a food item in the tip of its bill
and when the chick approaches to grab it with gaping
mouth the parent regurgitates water into the
nestlings bill before putting food.
The species has an
exceptionally wide vocal repertoire, including an
assortment of crowing and whining noises as well as
cuckoo-like staccato hoots and clucks.
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