Fluorescent bird droppings may help shed light on contested predictions in ecology. To keep species from becoming isolated in fragmented landscapes, conservation biologists often join the patches with strips of habitat, a strategy whose usefulness has been controversial. Ornithologists from the University of Florida at Gainesville and elsewhere devised a large-scale test of such corridors with eight sites in South Carolina pine forests. Each site contained a 100-meter-square patch with wax myrtle bushes, a key source of food for the eastern bluebird. This patch was surrounded by three isolated patches and connected to a fourth by a 150-meter-long corridor. After spraying the wax myrtle fruit with fluorescent powder and analyzing the resulting 11,000 fluorescent bluebird droppings, the researchers found the feces were 37 percent more likely to occur in the connected patch than in the isolated ones, suggesting corridors do work. Their report appears in the July 1 Science.