ocr: PADDLERS SAIL-LIKE Plumage FEATHER ON WING The feather male as part raises of this his T HE completely FEATHERS of waterproof. most Fatty swimming substances birds are courtship display made by the skin, and a special oil, keep the feathers waterproof. The oil is produced by a gland near the base of the tail, and the bird spreads it over its body when it preens. Ducks and geese often oil their feathers more than a ( dozen times a day, but females stop oiling while they are incubating their eggs, as they spend little time in the water. COURTSHIP COLORS The male's bright plumage is molted after ...
