Sciurids have been poorly studied in the Acadian forests of eastern North America, yet they represent common and ecologically important members of the forest community in the region. I gathered data on capture success and general life history traits of northern flying squirrels (Glaucomys sabrinus) and red squirrels (Tamiasciurus hudsonicus) in mature forest at Fundy National Park in southern New Brunswick, Canada. Squirrels were live-trapped over 14 sampling periods between 1999 and 2001. Flying squirrel capture success was considerably greater in summer and fall than in winter and spring, while red squirrels were caught more often in spring and summer than fall and winter. Capture success for both species was positively correlated with maximum daily temperature. Breeding seasons of both species began with male testes developing in winter and spring, followed by female pregnancy and lactation in late spring and summer. Flying squirrels may have also had an additional fall breeding season in the second year of the study. My data also suggest that G. sabrinus is smaller in eastern North America compared with western North America, where most data pertaining to this species has been gathered. There was no sexual dimorphism apparent in either flying squirrels or red squirrels.