PALLA’S GULL OR GREAT BLACK-HEADED GULL IS A LARGE GULL.THE ADULTS HAVE GREY WINGS AND BACK WITH CONSPICUOUS WHITE MIRRORS AT THE WING-TIPS.THE LEGS ARE YELLOW AND THE BILL IS RED.IN ALL OTHER PLUMAGES A DARK MASK THROUGH THE EYE INDICATES THE VESTIGES OF THE HOOD.THESE BIRDS ARE PREDATORY,TAKING FISH,CRUSTACEANS AND INSECTS AND EVEN SMALL MAMMALS.