REPRODUCTIVE CHRONOLOGY OF THE NORTHERN FLYING SQUIRREL ON THE OLYMPIC PENINSULA, WASHINGTON

The timing and frequency of breeding by northern flying squirrels (Gla ucomys sabrinus) on the Olympic Peninsula, Washington were inferred fr om seasonal changes in the occurrence of juvenile flying squirrel rema ins in the pellets of northern spotted owls (Strix occidentalis caurin a). Juvenile flying squirrels were uncommon or absent in the diet of s potted owls except during late August to early November. This suggeste d that breeding was largely concentrated in late May and early June, a nd that most females produced only a single litter in years when they bred. Infrequent breeding did occur outside the primary breeding seaso n, as evidenced by the occasional occurrence of juvenile remains in pe llets during mid-summer, late fall, and winter. Quantitative informati on on the population dynamics of flying squirrels and other arboreal m ammals is important to our understanding of forest communities in the Pacific Northwest.