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The Lesser Florican’s Multipurpose Wings

The Lesser Florican’s Multipurpose Wings

P.M. Lad unravels the mystery around the frog-like sound made by the Lesser Florican during its aerial courtship.

Photo: P.M Lad.

Close to sunset, the sun finally broke through the cloudy skies. It had been tiring looking for floricans through most of a rainy afternoon. Splashing through a narrow stream, still muddy after the recent rains, I walked up the low ridge in front of me. Florican! A hundred metres away, on the opposite ridge, a male florican stood looking around with an air of barely suppressed energy and excitement. Seemingly conscious of his looks, the florican ran his beak through the feathers of his glossy black neck and belly. While the plumes on his head waved in the gentle breeze, he shuffled his feet impatiently, as he surveyed the mosaic of emerging green around him. Then abruptly with a flash of white and a sharp carrying rattle, the florican fluttered off the ground before dropping back to the spot he took off from. With an amusingly cocky air, he did that endearing jump twice more, before hurrying away into the fast descending dusk.

– The late Ravi Sankaran, Sanctuary Vol. VII, No. 1, January-March 1987

The Lesser Florican is one of the most fascinating birds of India. Black plumes with flattened broad tips adorn the male’s head that is balanced on a long, curved neck. Except for white coverts at the shoulder and a white band across the upper back area, it is almost entirely jet black.

Little is known about its whereabouts during the non-breeding period as the bird is usually spotted only during the breeding season. It is best known for its aerial courtship when the male makes a series of spectacular jumps to a height of 1.5 to 2 m.

I find the frog-like sound made by the Lesser Florican during his aerial courtship rather intriguing. Incredibly, the call can be heard as far as 300 to 400 m. away. I knew that the jump was used to establish territory and serve as a warning to other males, and to relay information to the female about his location. These florican jumps may happen as often as 600 times in a day! Some reports suggest the bird may jump 150 times in an hour!

Calls play a vital role in mate selection. The Lesser Florican is otherwise a quiet bird. When surprised, it can make a sort of whistling sound and take to the air. The female makes a hissing sound when it is near a male or at the time of laying eggs.

My son Navendu and I were certain that the sound during its mating ritual did not emanate from the vocal box but rather its wings. We recorded the bird’s dance at Sailana, Ratlam in Madhya Pradesh in 2009 and 2012. Videos revealed that nine bits of sound are made during a jump that takes less than a second. The call period is 0.55 sec. There were nine sound bits along with nine wing beats. The sound bit interval was 0.06 sec. The sound bit duration was 0.006 to 0.016 sec. The frequency varied from 450 to 2,700 per second.

On both our visits in 2009 and 2012, we attempted to photograph the wing movement using our Nikon camera (lens 400 mm.). It was noticed that the primaries (primary feathers are the ‘fingertip’ feathers, the longest on a bird’s wing) are rotated around the carpal 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 seconds is what generates the sound.

The Lesser Florican’s signature loud call during its mating ritual emanates not from its vocal box, but from the split-second movement of its wings.
Photo: P.M Lad.

If you remember the sound made when you reverse-shake a wet towel before hanging it, you get some idea of the sound made by a Lesser Florican’s primaries. Half the primaries are modified for this purpose. They are soft and can bend both ways, which is critical to the production of the sound. The carpal joint also enables quick, round movement of the primaries. The wing muscles are modified for complex and rapid, simultaneous movement of the primaries to create the croaking sound that accompanies the male’s dance.

This acoustic phenomenon of the Lesser Florican is just one of its many intriguing characteristics. There is so much about the Florican we still don’t know. Their sex ratios, the relationship between mothers and chicks, how long they stay together, where they go during non-breeding months and how long they live in the wild. As of now, all we really have are theories. Hopefully, if we are able to successfully protect their grassland habitats, in due course, most of these baffling mysteries might be unveiled.

Photo:Modified Image.

Author: P.M. Lad, First appeared in: Sanctuary Asia, Vol. XXXVI No. 12, April 2016.

 
 
 

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