Three critically endangered spoon-billed sandpipers have been seen wintering in Danzhou Bay, south China's Hainan Province. It's the seventh consecutive year the rare birds have returned. The fist-sized species is known for its distinctive spoon-shaped bill. The birds were seen foraging on tidal mudflats, which are abundant in food after low tide. With a global population of only a few hundred, the spoon-billed sandpiper is a national Class-I protected species. Experts say this repeated return shows wetlands have been rehabilitated and China's protection plan is working.