TIANJIN -- Over 550,000 migratory birds have been spotted this spring in the four wetland nature reserves in North China's Tianjin municipality, according to the municipal Bureau of Planning and Natural Resources.

Over 60 migratory bird species have made the transit in the four wetland nature reserves this spring. Among these birds, the number of birds under the national first-class protection, such as the oriental white stork, larus relictus, and great bustard, is generally the same as that in previous years, said Jiao Xiaotong, an official with the bureau.

The number of white-napped cranes, rarely seen in the past, has reached more than 500 this year, showing a significant increase compared with previous years. The number of birds under the second-class national protection, such as the whooper swan, tundra swan, and white spoonbill, exceeded 80,000, a slight increase compared with previous years.

The peak migration period of migratory birds in Tianjin continues, and the migration period of migratory birds in spring will likely end in mid to late May, Jiao added.

To ensure the safety of migratory birds, Tianjin focuses on conducting inspections and patrols in habitats where migratory birds are concentrated. Tianjin severely cracks down on poaching, illegal trading, illegal consumption of migratory birds, and other illegal and criminal activities throughout the city while curbing unlawful acts that destroy migratory birds' resources, Jiao said.