A foraging technique in which a bird sweeps the partly opened bill from side to side in water or mud, straining out small animals and plant material with the specialized edges of the bill as the water (or mud) drains out. Sifting is used by Roseate Spoonbills, Northern Shovelers, and others. Found on https://academy.allaboutbirds.org/bird-academys-a-to-z-glossary-of-bird-ter