Lesser Florican is one of the most fascinating birds of India. It is not only
very beautiful but also mysterious. It is seen only during breeding season.
Nothing is known about its whereabouts during non-breeding period.
Another peculiarity is its jumping habit. Its arrival is noticed by jumps. It
stands at place, looks round and jumps to a height of 1.5 to 2 meters. It also
makes a frog-like croaking call during the jump. This jump is used to set up a
territory i.e. warning to other males also an information to females about its
location.
A Florican may jump up to 600 times in a day. Recently a bird was observed
jumping 150 times in an hour. The call can be heard from 300 to 400 meters.
How is this powerful call made? Florican is otherwise a silent bird. It makes
a sort of whistling sound while taking to wings when surprised. The female
makes hissing sound when near a male at the time of laying eggs.
Female
We were certain that the sound is made by wings. Video pictures revealed that
9 bits of sound are made during a jump which takes less than a second The call
period is 0.55 sec. The sound bit interval is 0.06 sec. The sound bit duration
is 0.006 to 0.016 sec. The frequency varies from 450 to 2700 per sec.
Primaries rotated round carpel joints
We
tried to photograph the wing movement It was noticed that primaries are
rotated around carpel joint during a wing beat by an angle of nearly 220
degrees and back. This fast reverse movement in less than 0.04 to 0.06 sec
generates sound. We were reminded of the sound made by the hunter of the
ringmaster in a circus. In day to day life when we long shake a wet towel
before hanging it on a wire. We are familiar with sound made by the towel.
Half the primaries are modified for this purpose. They are soft and can bend
both ways which is necessary for production of sound. The carpel joint is also
capable of very fast round movement of primaries. The wing muscles are also
modified for complex and very fast movement of the wing and primaries
simultaneously.
Showing modified primaries
