Deer Fence Research Articles

Attempted transmission of Brucella ovis between red deer stags by successive grazing or adjacent-paddock grazing

Aim: To determine whether Brucella ovis can be transmitted from stag to stag by successive grazing of infected and noninfected stags in the same paddock, or by grazing infected and non-infected stags in adjacent paddocks. Methods: Six red deer stags (Cervus elaphus) were artificially infected with B. ovis and 5 were confirmed to be shedding the organism in their semen. Infected stags alternated paddocks, and therefore grazing and wallows (successive grazing), once or twice weekly with 6 non-infected stags from 3 March to 18 August, 1999. Direct contact between the 2 groups of animals was prevented. The 2 groups alternated paddocks 32 times. Six other non-infected stags were grazed in a paddock adjacent to the infected stags throughout this period, separated by a standard deer fence. Non-infected stags were blood sampled at 2- to 6-week intervals to test for B. ovis antibodies using a complement fixation test and an enzyme linked immunosorbent assay. Results: No stag from either non-infected group became infected with B. ovis. Conclusions: The risk of stags becoming infected with B. ovis by successive grazing of the same paddock as, or by grazing in paddocks adjacent to, infected stags appears to be low. We conclude from this result, and similar experimental evidence and experience of this disease in sheep, that transmission of B. ovis requires animals to be grazed or confined together in a way that allows direct contact between animals. Clinical relevance: It is likely that infected and non-infected stags can be managed on the same property without transmission occurring between the groups, provided that they do not come into direct contact with one another.

The lengths of fences in Highland woods: the measure of a collision hazard to woodland birds

Birds die due to collisions with many static man-made objects, particularly wires (powerlines, ski-tows and fences) (Avery, 1978; Faanes, 1987; Bevanger, 1990; Alonso et al., 1994). Although these events are common, the effect that fatal collisions have on bird populations has rarely been studied. Catt et al. (1994a) found that capercaillie (Tetrao urogallus L.) living in native pinewoods in Scotland collided at a rate of 3 collisions km' a~' against 1.8 m high deer fences. This led to an annual mortality of 32 per cent, higher than all other causes of mortality combined. Further work showed that collisions against deer fences, particularly by gamebirds, were widespread in the Highlands of Scotland. In one year, 115 red grouse Lagopus lagopus (L.), 25 black grouse Tetrao tetrix L. and 31 capercaillie collided with 134.8 km of fences in and around woods, primarily conifer plantations. Smaller numbers of owls, pigeons and passerines also died (Petty, 1995; Baines and Summers, 1997). These mortalities are of conservation concern, particularly because capercaillie and black grouse are two of 23 species which have declined by over 50 per cent in

Assessment of Bird Collisions with Deer Fences in Scottish Forests

Bird collisions along 135 km of deer fences were monitored for I year at 27 sites in the Scottish Highlands. The majority (93%) of recorded collisions were by grouse species and at least 16% were fatal (carcasses found). In a trial testing how long carcasses would remain beside fences, 18 out of 20 were not relocated after 1 month. Red grouse Lagopus lagopus scoticus collisions were more frequent on fences surrounding pre-thicket plantations, while capercaillie Tetrao urogallus collisions were more frequent on fences in native pinewoods. The distribution of collisions differed seasonally. Two-thirds of both red grouse and black grouse T. tetrix collisions occurred between February and May, while capercaillie collisions occurred later, with a peak in September. Collisions by capercaillie were positively associated with areas of Vaccinium spp., whereas those by black grouse were negatively associated with grass and heather. This study adds weight to previous findings that fences are a frequent cause of mortality in capercaillie. Further work aimed at reducing collision rates is needed, but a policy of deer culling to achieve tree regeneration without deer fencing would be desirable wherever practicable and especially within the range and main native pinewood habitat of capercaillie.

Reduced Abundance of Ixodes scapularis (Acari: Ixodidae) with Exclusion of Deer by Electric Fencing

To assess the effect of deer exclusion on populations of Ixodes scapularis Say (formerly I. dammini Spielman, Clifford, Piesman & Corwin) in the northeastern United States, host-seeking ticks and ticks on white-footed mice, Peromyscus leucopus (Rafinesque), were monitored inside and outside a wooded, residential deer exclosure (approximately 3.5 ha) in Lyme, CT, in 1991 and 1992. Another deer exclosure was added in Lyme (approximately 7.4 ha) during 1992. Additional sample sites at other residences served as secondary controls. A seven-wire, slanted, high-tensile electric deer fence was used at both areas. Larvae of I. scapularis were 81.5% (1991) and 97.8% (1992) less abundant within the exclosure than immediately outside the deer exclosures. Nymphs of I. scapularis were 47.4% (1991) and 55.8% (1992) less abundant within the deer fence. The effect on adult ticks was mixed. No difference in tick abundance was seen at the 3.5-ha site. However, larvae, nymphs, and adults were 100, 83.8, and 74.1% less abundant, respectively, in plots at the 7.4-ha exclosure > or = 70 m from the deer fence and isolated from woodlands outside the fence by lawns, driveways, and buildings. The recovery of larvae and nymphs of I. scapularis from mice captured within the deer exclosures indicates that infestations of nymphs and adults are probably, at least in part, a result of the movement of these rodents. Based upon the number of nymphs per 100 m2 infected with Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, the causal agent of Lyme disease, there were 73 and 82% fewer infected nymphs within the deer exclosures in 1992 in comparison with the number of infected ticks outside the fence and at the secondary control sites, respectively. The exclusion of deer in conjunction with other tick control strategies in large areas could substantially reduce populations of I. scapularis and the risk of acquiring Lyme disease.

Studies on the ecology of Lyme disease in a deer forest in County Galway, Ireland.

The abundance of the tick Ixodes ricinus (L.) and the infection rate of ticks with Borrelia burgdorferi (Johnson et al.) were compared on either side of a deer fence in a forest park in County Galway, Ireland, in an attempt to elucidate the role of fallow deer, Dama dama, and woodmice, Apodemus sylvaticus, in determining the population density of I. ricinus and the transmission of B. burgdorferi. The results showed that tick numbers were much higher on the deer side of the fence, although the density of mice was similar on both sides. This suggests that, in the absence of other obvious factors, deer rather than mice are responsible for tick abundance in this habitat. Tick infection rates, determined by immunofluorescence, were consistently higher outside the deer fence than inside it. It is suggested, therefore, that mice rather than deer may be the important reservoir hosts of B. burgdorferi in this habitat and that deer, by feeding many larvae, probably contribute large numbers of uninfected ticks to the population. If this is the case, there will not be a direct relationship between deer abundance and tick infection rates. This has important implications for risk assessment.

Mule Deer-Induced Mortality of Mountain Big Sagebrush

AbStMCt A fence line contrast was provided by a deer fence that bisected a mountain big sagebrush (Artend& tridkntata sap. vaseyana) community. The ~pbruab community was located on an exposed, west-fadng slope that was generally swept free of snow during the severe winters of 1982-83 and 1983-84. On the freeway side of the fence, the site was essentially free of browsing animals, while above the fence, the shrubs were exposed to concentrations of mule deer (Odocoikus hemioms). Considerable big sagebrush mortality was evident after the 2 succeusive winters of heavy snowfall. Big sagebrush mortality and partial dieback of portions of the canopy were significantly (PCO.05) higher in the portion of the community exposed to browsing. Herbaceous species composition also differed between the protected and browsed areas with a higher portion of annual species found in the browsed community. A large number of big sagebrush seedlings germinated in 1984, but failed to establish by 1986. Excessive use of native plants by native large herbivores can have lasting effects on plant communitien.

Effects of Interstate Highway Fencing on White-Tailed Deer Activity

Locations of white-tailed deer (Odocoileus virginianus) along a 41.4-km section of Interstate 84 (I-84) right-of-way in Pike County, Pennsylvania, were determined by radio telemetry and spotlight surveys. Bucks crossed roads more often (P 0.05) between road-kills and highway direction, habitat, topography, or fence placement. However, deer were killed more often ≤0.48 km of an interchange. Management efforts to reduce the incidence of road-killed deer should address increasing the effectiveness of deer fence and decreasing the incentive for deer to enter the right-of-way.

A Modification of the Slanting Deer Fence

A Modification of the Slanting Deer Fence

Deer Fence Construction and Costs

Two 153-acre deer pens, consisting of 4.4 miles of boundary fence 81/2 feet high and 0.8 mile of fenced 1/4-acre exclosures, were constructed in 1964 at a total cost of $16,429: $6,816 for labor and right-of-way clearing and $9,613 for materials.

Stream-Crossing Structure for Deer Fence

The primary supports are two pressuretreated posts with 8-inch top diameters, one on each side of the stream (Fig. 1). To minimize the danger that they will be washed out during high water they are placed 6 feet back from the channel lips and are set 5 feet deep. Fence height will determine their length. The intermediate supports are set 6 feet in the ground on 5-foot centers, beginning 2? feet on each side of the stream center and extending outward. Pressure-treated poles or 3-inch galvanized pipes are suitable. Their length and number vary with depth and width of the drainage. The primary and intermediate supports e tied together by a 4x 6-inch pressuretreated bridge timber set 1'/2 feet above the bank level. The crossbeam is bolted to the downstream side of the primary supports with galvanized /2-inch bolts. Each intermediate support is secured to the upstream side of the beam by a galvanized U-bolt. When the span between primary supports is 12 feet or less, intermediate supports reach only to the top of the beam. On wider crossings, one or more of the intermediate supports must be high enough to hold up the line fence. To make a flat surface for attaching the 129