Abstract: I tested the hypothesis that female choice of nest location functions to increase opportunities for extra-pair copulations in dark-eyed juncos (Junco hyemalis).  Males with experimentally elevated testosterone levels are known to have more extra-pair fertilizations, and female behavior was examined in relation to male treatment type (elevated testosterone or control).  The defended territories of males were mapped during female fertile periods using song playback. There was no significant difference in territory size nor distance from the center of the territory to the nest among testosterone and control males.  Although not significant, a trend was observed in which females mated to control males nested in the periphery of the territory.