Field Guarding as a Crop Protection Method: Preliminary Implications for Improving Field Guarding

Camera traps and guard observations as an alternative to researcher observation for studying anthropogenic foraging

“…Smaller body size (Bolter & Zihlman, 2003;Dechow, 1983) and foraging party sizes (Butynski & de Jong, 2019;Sithaldeen, 2019) of vervets compared to baboons may also mean that guards often miss vervets when they enter the field. Researchers observing this field noticed that guards only responded to vervets in 15% of cases but to baboons in 85% of cases (Findlay & Hill, 2021b). Lower detection of smaller primate species has also been observed in other studies (Wallace, 2010).…”

“…While the presence of primates in the field does not necessarily mean crop-foraging was taking place, researchers did not observe any times when primates were inside the field without crop-foraging. Furthermore, using the term "cropforaging event" to refer to primates in the field maintains consistency with definitions used previously (Findlay & Hill, 2021a, 2021b. For the camera traps, we classed photographs as a new crop-foraging event if at least 30 min had passed since the previous photograph of the same species on any of the five cameras, to reduce issues of temporal dependence.…”

“…Like many other farms in the area, the study farm employed field guards to protect crops. These guards, normally women, were present at fields seven days a week during daylight hours and shouted, chased, and threw stones at wildlife entering crop fields to forage (Findlay & Hill, 2021b). We collected data on a single 1-ha field that the farmer felt had been most impacted by cropforaging in the past, close to natural vegetation and a river (Figure 1).…”

“…Subsistence farmers may chase any animals that attempt to forage on their crops (Hill, 2018) and in large-scale agriculture, farmers may hire crop guards to chase animals (Findlay & Hill, 2021b). These people regularly encounter animals foraging on anthropogenic foods.…”

“…Use of machine learning (Tabak et al, 2019) and citizen science (Swanson et al, 2015), or combinations of the two (Green et al, 2020;Willi et al, 2019), is reducing the time required for tagging images and data analysis is becoming simpler with packages like CamtrapR (Niedballa et al, 2016) providing full image to analysis workflows. Camera traps have already been used to answer questions about animals foraging on anthropogenic sources, providing data on the species (Abrahams et al, 2018;Findlay, 2016), numbers, identity, age, and sex distribution of foraging animals (Ranjeewa et al, 2015;Smit et al, 2019), as well as the effectiveness of deterrents (Branco et al, 2019;Findlay & Hill, 2021b;Ngama et al, 2018;Pozo et al, 2019;Ranjeewa et al, 2015), and the diurnal (Findlay & Hill, 2021a;Ranjeewa et al, 2015;Smit et al, 2019;Zak & Riley, 2017) and seasonal timings of crop-foraging (Zak & Riley, 2017). However, where camera traps have been used to assess crop-foraging in the past, what they can and cannot measure is often assumed.…”