Cowbirds sometimes appear to solicit preening both intra- and interspecifically; this head-down preening-invitation display has been well described by Chapman (1928), Selander and La Rue (1961), Selander (1964), Rothstein (1980), and Post and Wiley (1992). A Brown-headed Cowbird (Molothrus ater), for example, will approach another bird, point its bill downward, and freeze, presenting the crown and nape area.