Toxicity, survivability, and activity patterns of northern bobwhite quail dosed with the insecticide terbufos

Abstract

AbstractThe effects of the organophosphorus insecticide terbufos on laboratory‐reared and wild northern bobwhites (Colinus virginianus) were investigated in laboratory dosing studies and dose‐release field trials. Laboratory studies yielded a terbufos LD50 of 24.4 mg/kg‐body weight (bw). All mortalities occurred within the first 24 h post‐dose. Wild bobwhites were trapped, administered 0, 3, 5.6, or 21 mg/kg‐bw terbufos by oral intubation, released at their trapping site, and monitored for 14 d. Mortality, activity, and locational data were recorded. Bobwhites treated with 21 mg/kg‐bw terbufos had significantly lower survival (p = 0.04) than control birds, while survival at the lower doses was unaffected. No significant differences (p = 0.06) were detected in physical activity among treatments. The 21‐mg/kg‐bw dose yields an anticipated 37% mortality (or LD37) when interpolated from the LD50 slope equation. After adjustment for control mortality, the 21‐mg/kg‐bw dose led to 44% mortality in wild bobwhites. This was a 7% higher mortality than predicted by interpolation from the laboratory generated LD50. These results indicate that there was not a substantial increase in mortality of wild bobwhites compared to laboratory‐reared bobwhites at nonlethal or lethal, sub‐LD50, doses.