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Urban progress and nature sometimes will never see eye to eye at least that what it appears in Nanjing, capital of east China's Jiangsu Province.

 

Recently, some precious birds in a Nanjing zoo have stopped laying eggs since a new subway was built underneath it.

 

And while people are enjoying the convenience brought by the subway, some believe it appears the influence brought by the vibrating trains has changed the reproducing patterns of the birds.

 

A dozen species of precious birds have stopped laying eggs since the subway was built under the Hongshan Forest Zoo in Nanjing.

 

The city's No 1 subway line passes beneath the hill in the zoo where its precious birds live.

 

According to Bian Haixia, a bird breeder, the birds' situation has been worsening in line with the subway construction and operation.

 

Every African Ostrich in his zoo laid on average 16 eggs in 2002 and the success rate of insemination was as high as 85 percent.

 

Since the subway construction was initiated in October 2002 near the zoo, an African ostrich laid only 11 eggs in 2003 and seven eggs in 2004. They stopped laying eggs since 2005, the year the subway was put into operation.

 

Ten other national level protected birds have also stopped producing, including the black-neck bar-tailed pheasants who not only decreased in laying eggs but also broke their own eggs.

 

Bian says trains in the subway pass every three or four minutes under the hill, which in turn makes many of the birds run out of control.

 

"All of those 10 species of birds showing symptoms live at the foot of the hill and they are very sensitive to the vibration," said Bian.

 

"But the cocktails living on the top of the 150-metre-high hill seem unaffected," Bian added.

 

The zoo has currently assigned a team of experienced breeders to investigate into the incident to identify sources for birds' abnormal behaviors, according to Bian.

 

"If it proves the subway vibration is the generator, we will move those birds far away from the subway line. It might cost a lot of money since all the devices here are specially designed in accordance with the habits of those birds," said Bian.

 

But according to Professor Yan Peishi, an expert in the lifestyle of birds with Nanjing Agriculture University, the changes in temperature, sunshine, and excessive human intervention were major factors influencing the lifestyle of birds.

 

Yan said that he had never heard of subway vibrations influencing the biological circle of birds, but adds he did hear of cases when engine vibrations affected domestic birds in their breeding periods.

 

Subway construction experts in Nanjing were reserved in talking about the possible influence of subway vibrations on birds.

 

An official with the Nanjing Headquarter for Subway Construction said subways usually run underground with 60 decibels of noise.

 

However, he said that it had been estimated by experts that this noise level is "imperceptible" for living creatures on the ground.

 

(China Daily April 26, 2006)