The role of the white-eyed vireo in the dispersal of Bursera fruit on the Yucatan Peninsula

White-eyed vireos (Vireo griseus) winter in the forests and secondary growth of the Yucatan Peninsula where Bursera simaruba (Burseraceae) is an abundant tree. Twenty-five per cent of all white-eyed vireos observed foraging visited Bursera trees. In addition, presence and abundance of territorial white-eyed vireos in small forest patches were correlated with the size of the Bursera crop. Vireos were the most reliable dispersers of Bursera seeds. These birds visited 32 of 35 trees observed for at least three hours. They accounted for approximately half of all bird visits, and two-thirds of the seeds dispersed. Most of the other species rarely visited (