Razorbills (Alca torda) engaged in extrapair copulations (EPCs) during two phases of their breeding cycle when fertilization of eggs was not possible, suggesting that EPCs provide nongenetic benefits. Females actively pursued extrapair mountings after they completed egg laying, the first monogamous species reported to do so. Mountings were performed in mating arenas outside of the breeding colony, where attendance by postlaying females indicated that they sought encounters with extrapair males while their mates were incubating. Postlaying females always successfully resisted insemination yet positioned themselves to receive mountings. These findings support the hypothesis that resistance to insemination is a ploy used by females to appraise males. At the end of the breeding cycle, when males escorted the fledgling to sea, females remained at the colony where they consorted and sometimes copulated with other males. Nonfertilizable extrapair copulations may serve two social functions for razorbills: female appraisal of males for future fertilizable EPCs and the appraisal and acquisition of new mates by both sexes.