SIX years ago, Zhang Lin stunned his family when he announced that he was quitting a good, secure job with - ironically - a leading airline and heading into the woods to watch birds.

Sticking with his "weird" hobby despite family objections, the 32-year-old Shandong Province native has proved his doubters wrong. He can now earn more than 1,000 yuan (US$158) a day in one of the most unusual jobs in China - and for him the best - as one of only about 10 bird watcher guides in the country.

Zhang first fell in love with birds when just six years old, after he found an injured baby parakeet which he tended and set free. After that, he frequently purchased or caught birds, keeping them in cages and regarding them as friends. On weekends, he would go on bird watching trips with his father.

He majored in flight directing at Nanjing University of Aeronautics and Astronautics in 1999, but, armed with the book "Field Guide to the Birds of China," he took more delight bird watching on Nanjing's Purple Mountain than staying in the classroom.

After graduating, Zhang got a job as a controller with Shanghai Airlines, to the delight of his family. However, he was dissatisfied.

"But to me, the job was very boring and it took away too much time from watching birds," Zhang said.

For two years he spent his weekends and holidays travelling across the country bird watching, before taking the huge decision to quit his job.

"Of course my parents objected strongly as they couldn't understand why I would quit my job simply to watch birds," said Zhang. "But I'd noticed that bird guides in other countries could make a good living."

After spending some time travelling and watching birds, Zhang set himself up as a guide for foreign bird fans coming to China.

For the past six years, Zhang has spent six months of each year taking foreign bird watchers to spot rare species across the country. For the remainder, he is free to pursue his dream of traveling China's woods, coasts and wetlands, trying to record the country's more than 1,300 species of birds.

At noon on a hot Sunday recently, a group of bird watchers stood statue-still, holding their collective breath while peering intently into binoculars and telescopes, oblivious to the fact that their ankles were sinking into thick mud.

Before them lay a muddy expanse, partly flooded by an underground water source, on a remote construction site in Jiangsu Province's Rudong County, on the northern bank of the Yangtze River.

But through their scopes -- magnifying the scene 30 times - the unpromising landscape revealed in close-up the world of thousands of small wading birds eagerly hunting for food in the mud, squabbling with each other or gracefully resting on one leg.

This bird paradise, a vital stopover for migrating species, was accidentally discovered by Zhang. The local government, which had not even been aware of its existence, has not taken any measures to protect it. Instead, it is building chemical plants on the site.

The seven foreign "twitchers" remained silent, trying not to alarm the birds, until Zhang, a tall, thin man, broke the hush.

"Everyone, there is a spoon-billed sandpiper in my scope," he whispered.

Zhang had spotted the critically endangered species with a worldwide population which some estimates put as low as 500 individuals. The small wader breeds in northeastern Russia and winters in Southeast Asia.

To see such a rare bird, even if just for a brief period, helps explain why bird enthusiasts have travelled from as far afield as Australia and Scotland to the small county in Jiangsu. It is also why they hired Zhang as their guide.

After only about 30 minutes of observation, he had spotted a spoon-billed sandpiper - perhaps the only one - among a flock of more than 4,000 more common red-necked stints.

The only obvious difference between the two species of brown and light-colored birds, each around the size of a human fist, is the distinctive beak that gives the spoon-billed sandpiper its name, Zhang said.

Toughest part

"The toughest part of spotting a rare species among a huge flock is that you have to be patient while huge numbers of these little creatures are milling about," Zhang said, "And the rare bird could be one of those resting with their heads under their wings. So all you can do is to pray that they wake up soon."

With enough luck to win a 5 million yuan lottery prize, a skilled bird guide may find a rarity standing right in the middle of the scope. But most of the time, the guide must divide the birds into groups, scanning each in search of the jackpot, Zhang said.

Zhang's discovery of a spoon-billed sandpiper left the bird watchers elated. A species, driven almost to extinction by habitat loss and hunting had assumed almost legendary status. But here it was, standing in front of them, probing for invertebrates in the mud, moving its specialized bill from side to side.

Behind the twitchers were local workers, laying concrete on what had been part of the mud flat, building a chemical plant as part of a county project to boost the local economy. Some stopped for a moment and looked in puzzlement at the small group of foreigners peering at an expanse of mud.

In a country where hunting birds seems more attractive to many than looking at them, the general public are as baffled as the Rudong County chemical plant construction crew by the appeal of bird watching.

They ask, what's the point of bird watching? You don't take pictures? You don't get souvenirs? You don't take them back in cages?

In a flash, the flock of 4,000-plus tiny birds, seemingly alarmed by the "intruders," took to the wing. Each bird formed part of a huge cloud and quickly their movements synchronized so that they resembled a well-trained army or a programmed machine.

The black cloud transformed into all kinds of shapes - arrows, bubbles, separated circles. One moment, the cloud looked almost solid as the birds flew with their dark wings outstretched before the observers; the next they veered in unison and all but disappeared as their white bellies faced the viewer.

For some bird watchers, simply enjoying the beauty and surprise of nature is why they fell in love with the pastime.

"For me, the fun part is just to see them flying," said Doris Malcolm, who is in her eighties and came all the way from Scotland to see the birds of China. Carrying heavy equipment, she has travelled the world recording more than 5,000 bird species over the past 20 years - just for fun.

"I know many birds, but still I can't tell the names of some. But a blackbird doesn't know that it's called a blackbird," said Malcolm. "Just go out and enjoy it."

For Zhang, the best part of his work is that he can make a good living from his hobby and still be a "free bird" and go on his own trips. However, he admits that the job brings its dangers.

Zhang recalled that in 2009, when he was taking an American to watch birds in central China's Hunan Province, a sudden storm caused a mountain landslide that destroyed a bridge in front of their bus. The way out however, was blocked by heavy fallen trees.

They managed to get out of that, only to be caught in another rockfall.

"We stopped the car and waited for the obstructions to be removed, when yet more rocks crashed on to the road behind us. It was a close call," he said.

Despite the dangers, Zhang still managed to help the foreigner spot a species unique to the province. The American talked about their experience when back home, earning Zhang a good reputation among bird watchers.

On other occasions, Zhang and other bird watchers have encountered bird hunters armed with weapons such as rifles, slings and crossbows.

In the early days, Zhang admits that he would sometimes shoot birds to collect specimens, but soon stopped doing this and opposes hunting.

"In one case, a friend was in a hide taking a close-up photograph of a very rare water bird. Just after he took a perfect picture of the bird, it was shot by a crossbow and died right in front of him," Zhang recalled.

Angered by such an act, but knowing the risk of confrontations, the bird watchers could only report the incident to police.

"For me, the best part of bird watching is studying them," said Zhang, "By counting and watching their behavior, I can learn what is happening to the bird community."

One of his findings is, unsurprisingly, that the number of birds at the important stopover site in Rudong is dramatically declining due to the development of the chemical industry.

In 2008, when Zhang discovered the bird paradise with a friend, they counted 30,000 to 50,000 waders resting along the beach. But this year, the number is down to 20,000.

As Rudong is considered a vital stopover for migrating birds in the East Asian to Australasian migration flyway, Zhang knows that with the loss of habitat and degradation of what remains, some species may die out as they can no longer take a rest in the middle of their journey.

According to the China Costal Waterbird Census, a report written by bird watchers, the number of birds along much of China's coastline is decreasing.

"Fortunately, Rudong as a stopover site is becoming known by more and more people across the world," said Zhang.

"The World Wildlife Fund is to negotiate with the local government to persuade them do something to protect the site," said Zhang.

Although bird watching is popular in Western countries, ranking as the second most popular outdoor activity after gardening in the US, Zhang says more education about the hobby needs to be done in China.

"When some Chinese people head for protected species zones, they are thinking about how to eat the birds, not how to observe them," said Zhang.

"To establish the pastime we must let people know more about bird watching. Then, as awareness grows, there may be opportunities for more guides, and more concern for the species people are viewing," Zhang said.