Information on dispersal is critical for understanding the population
dynamics of birds. We estimated breeding and natal dispersal in two st
udies of a population of;he Puerto Rican Vireo (Vireo latimeri) that i
s in danger of local extirpation due to low reproductive success. From
7.1-29% of adult males and 12.5-25% of adult females changed territor
ies between breeding seasons. The median breeding dispersal distance o
f 12 birds (7 males, 2 females, and 3 of unknown sex) was 370 m (range
110-560 m). Four fledglings dispersed a median distance of 490 m from
their natal nests to breeding territories (range 300-2030 m). The imp
lications of these data for population trends of the vireo in Guanica
Forest are discussed.