Sex Difference in Natal Dispersal in the Eurasian Tree Sparrow Passer montanus

Abstract Avian dispersal patterns vary among populations and breeding conditions, although female passerine birds tend to disperse longer distances from natal sites than do males. Experimentally, we manipulated the breeding density of the Eurasian Tree Sparrow Passer montanus by establishing high and low nest-box density plots. We banded nestlings and recaptured them one year later. Females were more often found at non-natal sites than were males, and both males and females from high density plots dispersed shorter distances than those from low density plots.