ContextCamera traps paired with baits and scented lures can be used to monitor mesocarnivore populations, but not all attractants are equally effective. Several studies have investigated the efficacy of different attractants on the success of luring mesocarnivores to camera traps; fewer studies have examined the effect of human scent at camera traps. AimsWe sought to determine the effects of human scent, four attractants and the interaction between attractants and human scent in luring mesocarnivores to camera traps. Methods We compared the success of synthetic fermented egg (SFE), fatty acid scent (FAS) tablets, castor oil, and sardines against a control of no attractant in luring mesocarnivores to camera traps. We deployed each attractant and the control with either no regard to masking human scent or attempting to restrict human scent for a total of 10 treatments, and replicated treatments eight to nine times in two different phases. We investigated whether: (1) any attractants increased the probability of capturing a mesocarnivore at a camera trap; (2) not masking human scent affected the probability of capturing a mesocarnivore at a camera trap; and (3) any attractants increased the probability of repeat detections at a given camera trap. We also analysed the behaviour (i.e. speed and distance to attractant) of each mesocarnivore in relation to the attractants. Key resultsSardines improved capture success compared with the control treatments, whereas SFE, castor oil, and FAS tablets had no effect when all mesocarnivores were included in the analyses. Masking human scent did not affect detection rates in the multispecies analyses. Individually, the detection of some species depended on the interactions between masking (or not masking) human scent and some attractants. ConclusionsSardines were the most effective as a broad-based attractant for mesocarnivores. Mesocarnivores approached traps baited with sardines at slower rates, which allows for a higher success of capturing an image of the animal. ImplicationsHuman scent may not need to be masked when deploying camera traps for multispecies mesocarnivore studies, but researchers should be aware that individual species respond differently to attractants and may have higher capture success with species-specific attractants.

For camera‐trap studies to produce accurate data, cameras should have reliable detection of animals within their field of view. We reviewed 1,503,330 pictures obtained from August–September 2016 and February–March 2017 in North Carolina, USA, using 36 Reconyx® PC900 HyperFire cameras (Reconyx, Holmen, WI, USA). We evaluated factors related to temperature, wind speed, and whether specific detection band(s) and zone(s) may have increased the probability of triggering cameras. We focused on 10 species to determine species‐specific reasons for not triggering the camera. The odds of triggering the camera increased when an animal was detected in more zones. Additionally, there were more triggers than expected if an animal was observed in both detections bands as opposed to none. Triggered events were species‐dependent, seeming to favor larger species. The Passive Infrared Motion Detector (PIR) missed 14–16% of the independent events of bears (Ursus americanus), coyotes (Canis latrans), bobcats (Lynx rufus), and red wolves (C. rufus), and were overall ineffective at triggering for squirrels (92%; Sciurus spp.) and rabbits (80%; Sylvilagus spp.). Many (47–64%) of the independent events of gray fox (Urocyon cinereoargenteus), raccoons (Procyon lotor), white‐tailed deer (Odocoileus virginianus), and opossums (Didelphis virginiana) would have been missed if only the PIR function was used. The lack of detection of these species may underestimate occupancy and abundance estimates of these populations. Our results suggest that Reconyx HyperFire PC900 cameras have limitations as a broad, catch‐all system for monitoring wildlife as a result of the layout of their infrared detection zones. © 2019 The Wildlife Society.

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