Avian Guardian: Check out Beijing's busiest 'bird airport'

Over the past few days, Beijing's Guanting Reservoir has experienced the peak of this winter's bird migration. Since late October, nearly 40,000 migratory birds have arrived at the reservoir, and observers anticipate that the total number of birds staying there this year will surpass last year's recorded 60,000.

Reservoirs often serve as fixed "transit stations" during the migratory process. Sun Quanhui, PhD, a scientist at the World Animal Protection Association, explained that migration consumes a significant amount of energy for birds. Therefore, they must make stopovers to replenish their energy through foraging. Reservoirs often are the preferred "transit stations" for migratory birds because of their good environment. For long-distance migratory birds, these "transit stations" are relatively consistent. 

Beijing is on one of the world's eight major bird migration routes, and the Guanting Reservoir is the most crucial "bird airport" in northern Beijing. During peak periods, thousands of birds arrive at the reservoir daily for a stopover. So far, observers have counted 230 whooper swans, 211 tundra swans, and 673 Eurasian teals. The total number of these species is expected to exceed that of previous years based on current conditions.

Migration is a genetic trait among birds, and scientists have extensively researched how birds determine their migration destinations. Sun spoke of the "Ice Age Theory," which suggests that bird migration is related to changes in climate during the Ice Age. When cold temperatures begin and prolong, birds are forced to find unfrozen areas to inhabit. When the weather returns to a suitable temperature, birds can return to their original habitats for survival and reproduction. He said over time, the birds gradually find fixed migration locations.

Sun said the current large-scale gathering of migratory birds at the reservoir is attributed to the sudden arrival of recent cold waves. As cold waves cause a rapid drop in temperature in the birds' original habitats, migratory birds are compelled to search for warmer areas in advance. The situation has led to the spectacular assembly of migratory birds at Guanting Reservoir.

Sun further explains that in recent years, the protection efforts for the Guanting Reservoir have increased significantly, improving the ecological environment. It has attracted more and more migratory birds to transit here, resulting in the continuous growth of both the variety and quantity of migratory birds at the reservoir.

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