dove feed food forage forage for food pigeon Australian bird black-bill black-winged-stilt carnivores carnivorous dog-bird foraging himantopus-himantopus-leucocephalus long-beaked long-legged longshanks pied-stilt red-legged reflections ripples rippling sharp-beaked sharp-bill stilt stream thin wader wading water water-bird white-headed-stilt beak feather flightless grass grey head leg neck rhea walk