Following the closure of the Saemangeum seawall in South Korea in 2006 the Yalu jiang National Nature Reserve, Liaoning, China became the most important staging site in the EAAF for Great Knots Calidris tenuirostris on northward migration. Biomass of their main bivalve prey species Potomacorbula laevis at Yalu jiang NNR has decreased greatly in recent years and in 2015 some tagged Great Knots moved to Gaizhou at the head of Liaodong Bay, northern Bohai. Our surveys of this previously unknown site show that it is of international important for Great Knots as well as four other shorebirds and two gulls, however it is threatened by development. The discovery of this site highlights the value of continued satellite tagging of shorebirds to locate key staging sites and understand how birds respond to habitat loss and degradation.