Using motion-triggered cameras to estimate habitat use by collared peccaries

Longoria, Meredith P.
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Motion-triggered cameras (MTC) are used in a variety of wildlife research applications; however, few studies outline how to use MTC to collect reliable data on habitat use. Herein I outline how to use MTC for collecting reliable data on habitat use of collared peccaries (Pecari tajacu). Using MTC to measure habitat use of collared peccaries or other group-living ungulates is appealing because MTC can be used in a variety of environmental conditions, less time and effort is required to collect data than more commonly used methods, and unlike radio telemetry MTC can accommodate group size information. Group size may influence habitat use. I examined four issues that affect the reliability of MTC data: (1) the number of cameras needed to photograph collared peccaries at unbaited camera stations, (2) whether peccaries were alarmed by the presence of MTC, (3) the minimum distance needed between camera stations to obtain independent data, and (4) the proportion of landscape occupied by peccaries at 1, 2, 3, and 4-week intervals in order to estimate the probability of peccaries visiting unbaited camera stations. Four camera stations were established, each with 4 MTC positioned so that pairs of cameras were facing each other and perpendicular to the other pair of cameras. The study was conducted at Chaparral Wildlife Management Area (CWMA) in south Texas from March - November 2003. Two camera stations were established in closed-canopy habitat and 2 were established in open-canopy habitat. The influence of the number of MTC per station, habitat type (closed versus open canopy) and diel period on the number of peccaries counted in photographs and number of photographs taken across 7 consecutive 4-day time intervals was compared among camera stations using repeated measures analyses of variance. I did not detect a greater number of peccaries, relative to the number of cameras, with > 1 camera per station, and neither closed-canopy habitat nor photographs taken in the dark with a flash resulted in fewer peccaries counted or fewer photographs of peccaries taken. No avoidance or alarm response was associated with MTC as there were no differences in alarm behavior, number of peccaries counted in photographs, or number of photographs of peccaries taken at camera stations over 7 consecutive 4-day time intervals. The estimated maximum diameter of peccary home ranges calculated from telemetry data gathered at CWMA m 1994 and 1995 was 1.8 km. I surveyed 90 sign stations (0.25 ha circular plots) each week over 2 11-week sampling episodes for the presence of 0-4 day-old peccary sign (tracks, feces). From this data I estimated that peccaries occupied 25-50% of the landscape within 1-week intervals, 70-80% within 2-week intervals, >80% within 3- and 4-week intervals. Therefore, I recommend that stations have 2 opposite-facing cameras to insure that all peccaries are photographed and that camera stations at CWMA are ~1.8 km apart to collect independent data.
Habitats, Photography, Peccaries
Longoria, M. P. (2004). <i>Using motion-triggered cameras to estimate habitat use by collared peccaries</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.