Like his father, Zhang gets a great deal of pleasure from raising homing pigeons. He generally releases them twice a day and sits on the terrace to watch them for an hour.

He socializes with several neighbors who also raise the birds. Sometimes, while his neighbors are also releasing pigeons, they greet each other on the terrace.

"I am used to hard work, as I have to clean the pigeon loft every day. It's a tiring and dirty job," he said.

"My approach has changed over the years. You need to be very patient. If a pigeon doesn't come home, all you can do is wait. Life goes on and you have to adjust your mentality."

Dong Xiaobo, 53, has raised more than 1,000 pigeons in Beijing's Daxing district, some of them well-known breeds from Europe. The professional breeder prefers crossbreeds of European and Chinese species, as they have a better chance of winning races.

He travels to Europe to buy suitable pigeons that cost 1,500 to 1,700 euros ($1,668 to $1,890) each. However, the price for a champion bird can be dozens of times higher.

"The pigeons have an innate homing ability. They will generally return to their nests, using magnetoreception (use of a magnetic field to identify direction, altitude or location) and sunlight. If there is an earthquake in a neighboring country, it will also affect pigeons in China," Dong said.

"More and more people are raising homing pigeons, and a complete industrial chain has developed over the years, such as food, medicine and tools."

In the past, a special clock had to be used to calculate pigeons' times in a race, but now when the birds reach home, an electrical scanner in the loft reads their leg bands and uploads this information online.

Many pigeon owners, including Dong, are forced to rely on their experience to tell when a bird is ill, as few vets in China can treat pigeons.

"To perform well in races, you need plenty of research and communication with others. In the racing season, daily training sessions are necessary. You should also feed pigeons different food according to the season and provide them with nutrients," Dong said.