Experts called for more protection for Beijing swifts at a seminar in the Chinese capital on Monday, urging more research and the cultivation of a greener habitat for the migratory birds.

Wang Xiaoping, a senior official at the Beijing Municipal Forestry and Parks Bureau, told the seminar that by studying and protecting swift populations, Beijing aimed to cement its position as a leader in biodiversity conservation.

He said that thanks to conservation efforts, Beijing's forest coverage rate had increased from 1.3 percent in 1950 to nearly 45 percent by the end of last year.

"These endeavors showcase the collaborative efforts of generations in preserving Beijing's natural habitats," Wang said.

Beijing swifts migrate from Africa to Beijing in April and return to Africa in July, all while feeding, drinking, and even sleeping in midair. Wang said that by returning to Beijing over long distances each year, the birds had become a symbol of the city's biodiversity.

Liu Yang, a professor of ornithology at Sun Yat-sen University in Guangzhou, Guangdong province, said Beijing swifts passed through 37 countries during their migratory round trip.

He highlighted the importance of research in understanding the wintering grounds of Asian swifts, and said the use of lightweight geolocators had helped overcome the challenges of tracking small bird species during their migrations.

A study conducted by researchers from Beijing Normal University and Sun Yat-sen University studied the migration of adult swifts breeding in Beijing from 2014 to 2018, and analyzed full annual tracks obtained from 25 birds.

The study, which also involved experts from Sweden, Belgium and the United Kingdom, aimed to further understanding of the migratory behavior of swifts and contribute to their conservation.

Volunteers from the Beijing Bird-watching Society also played a role in the fieldwork, helping to band the birds and gather data.