Now I know which one is male!

The black-winged stilt is a widely distributed very long-legged wader in the avocet and stilt family. The scientific name "H. himantopus" was formerly applied to a single, almost cosmopolitan species. It is now normally applied to the form that is widespread in Eurosiberia and Africa and which was formerly regarded as the nominate subspecies of "Himantopus himantopus" "sensu lato".