NANCHANG -- A total of 12 migratory bean geese were spotted at Poyang Lake on Sunday, marking the arrival of this year's first overwintering birds at the country's largest freshwater lake, reserve authorities have said.

Their arrival came two days earlier than last year, according to an official of the lake's national reserve protection bureau in East China's Jiangxi province.

With its well-preserved ecosystem, Poyang Lake is a key wintering site for waterfowl in Asia. The peak migration period for birds traveling to the lake typically starts in mid-December and continues through early January.

Local authorities have launched routine patrols and other operations to combat illegal activities that could harm the wetlands, ensuring the safe wintering of the birds.