Patent ID: 8402630

Claim:
A method of controlling the movement of vertebrates, the method comprising installing an elongate barrier device along an elongate path which lies along the surface of the ground and which the vertebrates are expected to attempt to cross, the barrier device comprising (1) an elongate laminar sheet which comprises (a) an elongate lower portion which extends downwards from the elongate path into the ground to a depth of d inch below the surface of the ground, where d is 3 to 24 inch, and (b) an elongate laminar upper portion which (b1) extends upwards from the elongate, path and away from the ground to a height of h inch above the surface of the ground, where h is 12 to 60 inch, and (b2) comprises a laminar apertured sheet material wherein the apertures have a size and shape such that the force required to pull a sphere of diameter 0.375 inches through the sheet is at least 38 lbs, the apertured sheet material having a thickness and a laminar dimension at right angles to the thickness, and the apertured sheet material comprising a first set of first polymeric strands which (i) are parallel to each other, and (ii) are spaced-apart from each other with a distance between adjacent strands of 0.1 to 0.3 inch, and a second set of second polymeric strands which (i) are parallel to each other and at an angle of 30 to 90 degrees to the first strands, (ii) are bonded to the first strands at crossover points, and (iii) are spaced-apart from each other with a distance between adjacent strands of 0.1 to 0.3 inch, each of the first and second polymeric strands having a thickness in the laminar dimension of the sheet between the crossover points of 0.04 to 0.5 inch, and (2) a plurality of laterally spaced-apart posts which are secured to the ground and to which the upper portion of the elongate laminar sheet is secured.