Camera Traps in Animal Ecology by Allan F. O’Connell James D. Nichols & K. Ullas Karanth

Author:Allan F. O’Connell, James D. Nichols & K. Ullas Karanth
Language: eng
Format: epub
Publisher: Springer Japan, Tokyo

Sex ratios also vary across camera trap surveys (Table 8.3), but most surveys have recorded more males than females: from 3:2 (Maffei et al. 2004a, Soisalo and Cavalcanti 2006) to 4:1 (Kelly 2003, Wallace et al. 2003) and up to 9:0 (no animals positively identified as females, Silver et al. 2004). One exception is in the Darien, and two others in Atlantic forest: Iguazú and Moro do Diablo National Parks. In the latter two cases, the protected areas are islands of forest surrounded by heavily transformed landscapes and may provide breeding refuges for jaguars. Most radio telemetry studies report that males have larger home ranges than females (Crawshaw 1995; Cullen et al. 2005; Rabinowitz and Nottingham 1986; Scognamillo et al. 2002, 2003; Soisalo and Cavalcanti 2006), so we would assume that more females than males are present in any given area where there is a resident breeding population. However, males may have a higher capture probability because of larger home ranges that are presumably include relatively more cameras. In addition, males tend to walk more than females (Rabinowitz and Nottingham 1986) and use human trails/roads (where camera traps are almost always set) more than females (Salom-Pérez et al. 2007). Both radio telemetry and camera trapping studies suggest that multiple males and females overlap in their ranging patterns. Sites where females and cubs are present clearly represent conservation priorities. On the other hand, the failure to photograph females does not mean that they are absent from an area, but only that such areas should be evaluated more carefully to determine whether they function principally as corridors or dispersal areas, and whether they potentially represent population sinks.Table 8.3Adult sex ratios by jaguar survey site (cumulative where multiple surveys conducted), and locations where cubs/juveniles were photographed

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