The Body Ruffling Display of the Black-Capped Chickadee

Body ruffling displays of Black-capped Chickadees (Parus atricapillus) consist of extreme ruffling of the breast and back feathers and often are associated with wing extension and spread primaries. Body ruffling was observed throughout the non-breeding season but was more frequent in the fall. Birds of all ages and sexes exhibited the display, but juvenile males did so most frequently. Body ruffling was directed toward individuals of any age or sex and to familiar as well as to new birds in the area. Contrary to our prediction, the display was given less frequently, rather than more frequently, toward the eventual mate of the displayer. The seasonal frequency of the display paralleled the frequency of arrival of new birds at the feeders rather than the frequency of all aggressive behavior. The display appears to function in maintaining individual distance and gaining access to food, and it is not involved in pair formation as has been suggested for other parids.