Deer Use of a Right-of-Way in Central Pennsylvania, U.S.

RESULTS AND DISCUSSION

Only nine and 11 deer were observed on the ROW in 2006 and 2007, respectively. This low number of deer using the ROW is not unexpected because deer are highly mobile (Storm et al. 1995), early successional habitat was lacking on the SGL 33 ROW (Smith and Coggin 1984), the ROW traverses mature forest (greater than 80 years since last cutting), and the general region (including the ROW) is hunted regularly for deer. Based on 8 months per year and 6 days per month, this is 2.1 deer per 10 days of observation on the ROW during both years combined from March to October. By comparison, over twice as many (4.8 deer per 100 days; n = 42 total deer) were seen in fields within 5 km of the ROW or in food plots established by the Pennsylvania Game Commission within an approximate 500 and 150 m of the ROW. These food plots were planted in pasture mixes of grasses and mowed periodically to encourage sprouting of nutritive food for deer (Forbes et al. 1971). When compared with the ROW at SGL 33, 22 deer were seen on the Green Lane ROW in Montgomery County, southeastern Pennsylvania in 2007, which equates to nearly sevenfold the number of deer (13.8 deer per 10 days) per observation day (Yahner 2007). Moreover, no deer were seen along roads or in fields in 2007 within 5 km of the Green Lane ROW. This suggests that both deer populations and suitable habitat on the ROW are less on the SGL 33 ROW compared with the Green Lane ROW. The Green Lane ROW traverses residential areas, which are not heavily hunted by deer hunters, and the Green Lane ROW was maintained in 2004 (Yahner 2006), thereby providing less hunting pressure, combined with more suitable habitat, e.g., grass cover type, on and in the general region of the ROW (Smith and Coggin 1984).

Browsing by deer on undesirable tree species was greater (70% of total trees browsed) in wire zones compared with border zones (50%) (χ² = 6.7, df = 1, P = 0.01; Table 1). Regardless of treatment, average percentage of undesirable trees was at least 50% in wire zones of all treatments, but browsing did not exceed 50% in only two of the five treatments in border zones. Perhaps deer readily found browse in the more “open” wire zones than in the “closed” border zones. Trees and shrubs in border zones likely impeded movements and raised the energetic costs of foraging by deer in border than in wire zones. In comparison, only 30% of undesirable trees of height in the contiguous forest, which were similar in height to those on the adjacent ROW, were browsed by deer.

Tracks of ten deer were detected; all tracks were found in border zones. However, I viewed this as an unreliable indication of deer use of the ROW for two reasons. First, tracks are ephemeral and may not be a good method to detect deer use of the ROW. Second, more tracks in border zones rather than in wire zones might be expected because of the cover afforded by border zones (deer more cryptic, protection against wind) and because of the high winds that caused snow drifting over potential tracks in wire zones. Only two pellet groups were found within established transects with one each per zone. Two buck rubs were noted along the entire ROW (one per zone).

In the next couple of years with the progression of plant succession after maintenance in late June 2007, I would expect more deer to use the ROW beginning in Spring 2008. I would predict greater deer use of the ROW, especially in units containing appreciable grass cover, likes with mowing and mowing plus herbicide units. Deer are known not only as browsers, but also as grazers (Beier 1987; Cypher et al. 1988). Adult females, in particular, more so than adult males, use grass as a food resource on a year-round basis (Beier 1987; McCullough et al. 1989). Thus, future years of research should indicate greater use, and perhaps greater abundance, of deer on the State Game Lands 33 ROW.