Wednesday, January 5, 2011

The Great Indian Bottleneck

He wore a black cap and a brown jacket spotted white. He looked over everyone as he was the tallest and the most magnificent. Around him, the others stood at distant spots, marking their circles, occasionally getting into a brawl.

From afar it looked like a dance, spectacular choreography and co-ordination. These were the Great Indian Bustards and the act was 'lek'.

This superior system of mating (lek comes from Swedish: which means 'play') is practiced by many species, including the Bustards. The male described above is the alpha male, who witnesses the procedure at the centre - the spotlight.

Birds that practice lek meet at the same 'lek arena' every mating season. The alpha and beta males (the most dominant males) take the prestigious centre position, while the others spread out in all directions in a circle, positioning themselves at suitable spots.

The call
The show starts - the males inflate a pouch near their throat called the gular sac, which then hangs below their necks. They hold their tails up against their body and emit an occasional deep call (known as Hoom: Maharashtra, Hoonka: Nothern India).

Sometimes, territorial fights break out - males fight by charging their opponents using their legs. Wrestling, they lock each other head under neck. It could get pretty gruesome, but the overall experience paints a picturesque image.

The climax of the act comes with humans appearing in various directions. From the west, men in white overalls come in Jeeps. The birds cannot outrun the vehicles. The men use ropes and hoops to catch their prey.

From the east, tribal folk set nests on fire. Female bustards run towards their babies, scorching their wings, only to be caught and slaughtered.

And from the north, men with hats and thick moustaches appear with guns. The picturesque image turns into a blood bath. The birds are cooked, spiced and eaten - sometimes pieces such as legs and breasts are packed and transported to places that consider their flesh as delicacies.

This play depicts the life history of these harmless birds. They have been mentioned in the books of the Moghuls and by the British soldiers during the colonisation of India. The Great Indian Bustard that was once a candidate for the national bird of India, whose booming call could be heard all over India, is now a vanishing population of less than 1000 birds throughout the country.

The fall
A census conducted in 1969 estimated a total population of 1,260 individuals. Then in 2008, the count was an alarming 300! The IUCN Red List 2002 and Birdlife International (Red Book 2000) have classified the Great Indian Bustard as endangered.

These birds were found throughout India but are now confined to parts of Rajasthan, Gujarat, Maharashtra, Madhya Pradesh, Andhra Pradesh and Karnataka. They are protected in 12 sanctuaries but have completely disappeared from two.

Every year, the Pune forest department conducts census of the Great Indian Bustards, which covers the Rahekuri Black Buck sanctuary in Ahmednagar district, the Great Indian Bustard sanctuary in Karmala and Nannaj in Solapur district.

In the year 2010, the estimate was just 9 individuals in Nannaj. This year, fortunately, the bird population had increased to 13.

This significant improvement of population may not justify the reduction in the bird's population by 82% in the last 47 years possibly due to mismanagement of sanctuaries, corruption and poaching... but there is a start.

A study this year carried out by scientists from the Wildlife Institute of India suggests that the reduction in population of the Great Indian Bustard may have occurred due to low genetic diversity.

Genetic diversity - variations in genes between individuals of a population - is important for the species to survive.

Let's take an example: in Rajasthan, the increased use of the Indira Gandhi canal has led to increased agriculture. Since the Great Indian Bustards inhabited low grasslands and arid areas, they could not adapt to the changing agricultural landscape.

Now why did this happen?

If one or a few of the birds adapted to this change by, say, laying eggs in a bush rather than on the ground, then a positive change like this would be transferred to a many later generations. Of course this is a very coarse example and changes that happen at the genetic level usually take several thousand years to happen.

But the crux of the research focused on studying this variation which had not happened - ultimately leading to low genetic variation and a population bottleneck. The scientists suggest in a paper that IUCN should upgrade the status of these birds from 'endangered' to 'critically endangered'.

The Great Indian Bustard stands around a metre tall and weights around 15kgs. It feeds on insects, seeds and berries. When threatened, the females are said to carry their infants under their wings.

Would we let these magnificent creatures become extinct?


Post a Comment