Add to ORKGBecause of the lack of long-term studies on the population dynamics of pine voles in Pennsylvania orchards, a study intended to collect various population parameters was initiated in Adams County in November 1973 and continued until November 1977. Two orchards, 0.3 km apart, were chosen for study. Pine voles in Orchard A were live-trapped, and those in Orchard B were snap-trapped. Population density estimates were determined from capture-recapture data from Orchard A, and information on age structure, reproduction, and physical condition were recorded from necropsied voles from Orchard B. Both orchards were maintained and treated by orchard personnel with Endrin ground spray and/or zinc phosphide bait each year