'Cat-beside-mousehole-technique' employed by Nordmann's Greenshank hunting for crabs

摘要

Observations of individual Nordmann's Greenshanks Tringa guttifer on marine mudflats in the non-breeding season show that to a large extent the species feeds on crabs living in burrows in the mud (Bijlsma & de Roder 1986, Howes & Lambert 1987, Swennen & Park 1991). The species' foraging behavior is described as running or walking rapidly about the mudflats searching for prey, and when encountering crabs trying to grab them or dig them out of their burrows with the bill. Recently, a case has even been described of a Nordmann's Greenshank in flight repeatedly snatching prey (crabs or mud-skippers) from a mudflat surface (Zockler & Frew 2011). On a visit to the intertidal mudflats at Yangkou, Rudong, China, in spring we observed crab-hunting in this species different from the swift search method described above.