The Flapping Frequency of Dust Bathing in Birds

Birds remove excess lipids and ectoparasites from the plumage by dust bathing. During dust bathing, birds scratch their legs to get loose sand particles onto their bodies and flap their wings to shake them off in seconds, but this mechanism is poorly understood. In this study, we collect thirty videos on dust bathing in birds with masses across four orders of magnitude. The flapping frequency is in the range of 1 to 10 Hz. Among these birds, land fowl such as chickens and ostriches have the flapping frequency decreasing with body mass ranging from 0.1 to 88 kg. We hypothesize that larger land fowl have a slower flapping frequency because of a limited wingspan during dust bathing. This study may shed light on the bioinspired dry cleaning technologies such as oil-resist mechanisms in sensors and cameras.