The Influence of Environmental Factors on the Detection of Gamebirds by Pointing Dogs in the KwaZulu-Natal Midland Grasslands of South Africa

Abstract

Pointing dogs (Canis lupus familiaris) are primarily used to locate cryptic species or evidence thereof and often to establish their abundance. Environmental conditions at the time of search may influence the probability that a dog will detect a target. Here, we aimed to determine the environmental factors that affected the detection rate of a pointing dog detecting gamebirds in their natural environment under known atmospheric conditions, including temperature, humidity, barometric pressure, wind strength and solar radiation. We conducted uncontrolled trials in the Greater uMngeni Vlei Expansion Area of the KwaZulu-Natal Midlands, South Africa, between August 2020 – October 2021, where up to two pointing dogs repeatedly (n = 44) surveyed an environment with an abundance of Red-winged Francolin (Scleroptila levaillantii ). The index of abundance, measured as birds/minute of search, was compared for each survey whilst simultaneously monitoring the environmental conditions. We conducted controlled trials (n = 34) in the same region concurrently by independently casting two pointing dogs downwind of caged Japanese Quail (Coturnix japonica) of a known location to observe the point where each dog's behaviour changed to indicate scent detection. This approach enabled us to measure detection distance whilst simultaneously monitoring environmental conditions. We found that the index of abundance showed no correlation with any of the monitored environmental factors in the uncontrolled trials, most probably because of the low incidence of detection. We further established in controlled trials that detection distance was uncorrelated to ambient temperature and relative humidity but significantly positively correlated with solar radiation and wind strength. An increase of one-knot wind strength resulted in an increase in detection distance by 0.64 m. Our study lays the foundation for developing an area-based survey method, considerate of environmental conditions, to detect cryptic bird species by dogs in conservation projects.