avocet: long-legged web-footed black-and-white shorebird with slender upward-curving bill
wading bird: any of many long-legged birds that wade in water in search of food
silica: a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth's crust as quartz or cristobalite or tridymite or lechatelierite