Short communication: Levels of land use and land cover in Phoenix, Arizona are associated with elevated plasma triglycerides in the Gambel's Quail, Callipepla gambelii

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Gambel's Quail, Callipepla gambelii, are gregarious birds commonly found in the southwestern deserts of the United States and Northwestern Mexico. With expanding urbanization, these birds are often found in exurban and suburban areas where they have access to food sources that may differ from those used by birds living in rural habitats and, as a result, also differ morphologically and physiologically. To investigate this hypothesis, we compared the morphology and nutritional physiology of quail sampled at sites varying with respect to land use and cover. We hypothesized that quail living in more developed areas have access to a greater variety of and to more stable food resources, and predicted that morphology and nutritional physiology would be associated with degree of urbanization. We sampled adult birds at locations in the greater Phoenix metropolitan, Arizona (USA) area that vary with respect to land use and cover types. At the time of capture, birds were weighed and chest circumference was recorded. We also collected a blood sample from the jugular vein of each individual for analysis of plasma glucose, total proteins, triglycerides, and free glycerol. Consistent with the hypothesis, birds living in more developed environments had larger chest circumferences and higher circulating lipid concentrations than birds living in less developed areas, suggesting greater access to lipid-rich foods. In addition, the areal proportion of grass and lakes was negatively correlated to plasma free glycerol (r = −0.46, p = .031), and positively, but not significantly, correlated to plasma protein concentrations (r = 0.388, p = .073). These results suggest that quail living in areas with more grass have access to less dietary fats than urban birds. The findings are the first to indicate an association between urbanization and the morphology and nutritional physiology of Gambel's Quail, but further study using more and larger samples is needed before these findings can be generalized.