Arboreal Habitat Use and Parachuting by a Subtropical Forest Frog

Abstract

ABSTRACr.-Eleutherodactylus coqui in the Luquillo Experimental Forest of Puerto Rico uses most of the vertical spectrum of its habitat at some time during life. Weather permitting, subadults, small adults, a few adult males, and non-breeding females climb tree trunks at dusk to forage in the canopy. Most adult males remain on understory call sites during the night. Juveniles remain in retreats or on vegetation near the ground. At dawn, frogs parachute to the ground, then return to diurnal retreats on or near the ground. Of subadults and adults counted in transects in July-August, approximately 43% climbed to the canopy at dusk, 39% in January. Significantly more frogs climb after wet days than after dry days in both seasons. Every continent having trees has species of frogs that use the arboreal habitat. By foraging in the canopy as well as at lower levels frogs may broaden their food niche to include canopy invertebrates, and predation by frogs may influence populations of canopy arthropods. In the trees, frogs avoid ground-dwelling predators, yet may encounter arboreal predators. Although there are many tree frogs throughout the world, especially in the humid tropics, I know of no study that has quantified their use of the arboreal habitat. The reasons are obvious: how does one