Poor health is associated with use of anthropogenic resources in an urban carnivore

Abstract

Rates of encounters between humans and wildlife are increasing in cities around the world, especially when wildlife overlap with people in time, space and resources. Coyotes (Canis latrans) can make use of anthropogenic resources and reported rates of conflict have increased in cities across North America. This increase may be linked to individual differences in the use of human food and developed areas. We compared the relationships between coyote age, sex or health and the use of anthropogenic resources, which we defined as using developed areas over large home ranges, being active during the day, and consuming anthropogenic food. To do so, we applied GPS collars to 19 coyotes and sampled hair for stable isotope analysis. Eleven coyotes appeared to be healthy and eight were visibly infested with sarcoptic mange (Sarcoptes scabiei), a mite that causes hair loss. Diseased coyotes used more developed areas, had larger monthly home ranges, were more active during the day, and assimilated less protein than coyotes that appeared to be healthy. We speculate that anthropogenic food provides a low-quality but easily accessible food source for diseased coyotes, which in turn may increase reliance on it and other anthropogenic resources to promote encounters with people.

Keywords: Canis latrans; human–wildlife conflict; spatial ecology; stable isotope analysis; urban adapters; wildlife disease.

Figure 1.

Map of study area showing the capture locations (white circles), 3 h GPS locations (points) and 95% utilization distribution home ranges (polygons) for GPS-collared coyotes that were apparently healthy (n = 11; a) or were visibly diseased (n = 8; b). Colours distinguish individual coyotes and land use types, either developed (grey) or urban natural areas (green). (c) Aerial photo of map section of Edmonton from Google Earth.

Figure 2.

Signs of sarcoptic mange Sarcoptes scabiei (a) used to visually assess coyote health status at time of capture. Coyotes we classified as exhibiting mange at time of capture had lesions on (b) hind legs and (c) forelegs which could progress to the tail (d), the face (e) and in severe cases, over the whole body (f). Photo credit (a) Wikimedia, all others from authors.

Figure 3.

Differences in space use between apparently healthy (n = 11; blue) and coyotes with visible ectoparasite infestations (n = 8; red), including (a) habitat selection, (b) home range size and (c) activity patterns. Columns show averages across individuals and bars show standard deviations.

Figure 4.

Assimilated diets of urban coyotes. (a) Isotopic δ¹⁵N and δ¹³C signatures for visibly diseased (n = 11, red) and healthy (n = 12, blue), and food sources we grouped as prey (squares), fruit (diamonds) and anthropogenic food (triangles). Bars show standard deviations. (b) Proportional contribution of anthropogenic food, fruit and prey to the diet of healthy and diseased coyotes as modelled by a three-source mixing model (SIAR). Bars show the 50, 75 and 95% CIs, respectively, with lighter shades.