HOHHOT - Nearly 100 great bustards have been seen in North China's Inner Mongolia autonomous region recently, local forest police said Friday.

Great bustards are a Class A protected animal in China and are classified as "vulnerable" by the International Union for Conservation of Nature.

The huge birds, amongst the heaviest living flying animals, were found staying and foraging near lakes and farms in Tuquan county, the Hinggan League.

The number of great bustards has gradually increased in recent years along with improvement of the ecological environment in the Hinggan League, said Shen Zhihong, head of the county's public security bureau for forestry.

The adult male great bustard can range in weight from 15 to 20 kg. "They fly slow and look clumsy because they are heavy," said Shen, adding great bustards are very vigilant. They flew away when police officers spotted them 1 km away.

The local forest police said better air quality, improved water quality and increased forest coverage have attracted more rare animals to the league.