Patterns of Nest Box Use Among Squirrels (Sciuridae) in Managed Forest Stands in Clinton County, New York

Abstract

Both natural and artificial habitat enhancements can be the structural component that increases the fitness of squirrels (Sciuridae) and thus warrant study. These structures can provide useful demographic and community information about wildlife populations, such as occupancy rates, litter size, habitat preference, as well as species richness and abundance estimates. This artificial nest box study aims to investigate the nesting patterns of squirrels from late winter through early fall 2011 in managed mixed forest stands within Clinton County, New York. It is known that squirrels are very sensitive to forest disturbance, hence we compared sites of varying silvicutural impacts (e.g., managed for logging and maple sugaring versus a control). A total of 48 nest boxes (16 per site) were constructed, across 4 stands. Weekly measurements of abiotic variables were recorded and biotic variables were examined which included wildlife point counts and nest box occupancy. Occupancy may be a function of nest box height (~3.5m and ~5m), site-specific tree cavity/ snags/drey abundance, thus they were surveyed. Of nest boxes, approximately 81%, 44%, and 13% in the control, logged and maple sugar site, respectively, had visual confirmations of Glaucomys sabrinus (Northern flying squirrel), with one observation of Sciurus carolinensis (Red squirrels). The first noted incidence of nest box occupancy was observed on 20 March, 2011 approximately two weeks after erection at the control site. Additionally, approximately 79% of nest boxes show evidence of wildlife visitation (e.g., scat, crushed seeds, or nesting material), 87% of the high boxes versus 71% of the low boxes were utilized, and 17% of all occupancies contained multiple individuals. This survey provides additional multi-season occupancy data for an elusive mammal species under managed habitat regimes. We suggest forest managers, and conservation biologists alike, attempt to reduce the removal rate of snags and trees with cavities in their daily practices, as these features can enhance the nesting success of squirrels. Additionally, if faced with logging, managers should implement habitat enhancements (e.g., nest box addition) to offer long-term housing and protective refugia for squirrels.