a strong trendp < 0.0001
Drone mortality followed a similar trend as in experiment 1 with a strong trend toward higher mortality among the control treatment ( χ 2 1 = 47.0; p < 0.0001) driven by strong differences in mortality among control sources ( χ 2 2 = 84.3; p < 0.0001) rather than treatment sources ( χ 2 1 = 1.3 × 10 −30 ; p = 1) and a clear confounded factor of near total mortality of a single control source (Fig. 2d ).