Proceedings of the fifth mountain lion workshop: 27

More documents

Recommendations

Info

36 PROCEEDINGS OF THE FIFTH MOUNTAIN LION WORKSHOP emphasis on the black-footed ferret (Mustela nigripes). Rev. Scient. et Tech. de l'office Internat. des Epizooties 15:91-114. Wood, S.L., G.W. Thomson, and D.M. Haines. 1995. Canine distemper virus-like particles in a captive African lioness. Can. Vet. J. 36(1):34-35. Yamamoto, J.K., H. Hansen, E.W. Ho, et al. 1989. Epidemiology and clinical aspects of feline immunodeficiency virus in cats from the continental US and Canada and possible mode of transmission. J. Am. Vet. Med. Assoc. 194:213-220.
PROCEEDINGS OF THE FIFTH MOUNTAIN LION WORKSHOP 37 STANDARDIZING PHOTOGRAPHS OF PUMA TRACKS FOR DIGITAL PROCESSING Steve Galentine. Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, California 95616. E.L. Fitzhugh. Cooperative Extension, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, California 95616. Key words: Mountain Lion, Puma concolor, Tracks, Techniques Abstract We designed a portable camera mount that provides photographs of animal tracks, taken perpendicular to the substrate, of consistent quality and size. The camera sits on a folding black box. Opposing flash units are mounted at different levels depending on the depth of the track. We identified appropriate filters for the film, aperture, and flash units we used, although these will vary and may be improved upon. Scientific attention has been directed recently toward using animal tracks to 1) identify species, 2) index populations, and 3) identify individual animals. One aspect of some of these techniques involves computerized measurement of track dimensions and areas. To accomplish computer measurements, the track outlines and other features must first be identified (digitized) for the computer. Tracks traced on acetate or plastic film are relatively easily and accurately digitized, but tracing the tracks in the field requires valuable field time and the tracings may be distorted by parallax. Parallax is caused by light rays that bend when they pass from the glass plate on which the tracing is made to the air above and below the plate. If the eye of the tracer is not perpendicular to the glass at the exact spot being traced, this bending, or parallax, occurs and distorts the image. A similar error can exist in photographs not taken from a perpendicular perspective. Photographs greatly reduce field time, and can eliminate the parallax error if they are taken from a location perpendicular to the substrate the track is on (not necessarily vertical). Photographs, however, must be digitized in the office. If the photographs, or their computer images, are of variable quality and size, the human error involved in identifying the true outlines and features may sometimes be greater than errors made by tracing in the field. Shallow tracks in light-colored substrates often lack detail in photographs, making the outline hard to identify. Deep tracks with side-lighting sometimes contain dark shadows on one side of the track just at the point where the vertical wall of the impression curves toward the horizontal bottom of the track. This area of curvature is where detail is needed to properly identify the outline of the track. The goal of this project is to develop a standardized apparatus and new techniques to enable researchers and wildlife managers to take the best possible photographs of mountain lion tracks. Substrate type and ambient light conditions are two of the major factors affecting the quality of photographs of tracks. Since we have no control over where an animal may walk and leave a track we focused our attention on the light factor to improve our photographs. To eliminate variation in this factor we developed the idea of a "black box" that would enable us to standardize light using camera flash units. We tested single and opposing flash units at various heights on different substrates and depths of tracks. We also experimented with flash filters, lens filters, and various camera settings. The result was a collapsible, portable camera mount, or "black box" designed to provide photographs of tracks taken perpendicular to the substrate, of consistent quality and size. METHODS Tests were done to learn proper exposure settings, filters, and number and location of flash units. Equipment Nikon F2 camera 35 mm lens 2 ea. Vivitar 2000 flash units Multi-flash adapter 2 ea flash cords 52 mm. Hoya circular polarizer PL-CIR 52 mm. Tiffen lens filter, red 1 52 mm. Tiffen lens filter, yellow 2(8) 52 mm. Tiffen lens filter, neutral density N.D. O6 Kodak Kodachrome 64 slide film Dark gray window tint, "Gila" non-reflective, 35% Dark Smoke (for flash filter) Procedures We first learned the shortest distance our equipment would focus. Using that as a guide, we constructed a collapsible 15-inch cubic box, with one side open. The opposite side had a circular hole in the center just large enough for the camera lens to fit through. We painted the box black to reduce light reflectance inside. We fitted the flash attachments through horizontal holes cut in the shape of the flash units. The bottoms of the holes were 2 inches, 4 inches, and 6 inches from the bottom of the box. These holes were directly opposite each other on two sides of the box.
Page 1: PROCEEDINGS OF THE FIFTH MOUNTAIN L
Page 4 and 5: © Copyright 1997 The Southern Cali
Page 6 and 7: PROCEEDINGS OF THE FIFTH MOUNTAIN L
Page 12 and 13: 2 PROCEEDINGS OF THE FIFTH MOUNTAIN
Page 20 and 21: 10 PROCEEDINGS OF THE FIFTH MOUNTAI
Page 96 and 97:
86 PROCEEDINGS OF THE FIFTH MOUNTAI
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
100 PROCEEDINGS OF THE FIFTH MOUNTA
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
show all

Proceedings of the fifth mountain lion workshop: 27

Create successful ePaper yourself

Delete template?

Save as template?