Fig. 3: Moth-background colour discrimination for birds under artificial light.

Bootstrapped estimates of the distance (in Delta-S) between the geometric means of moth forewing colours (Nmoths = 235) and background colours (Ngreen = 871, (Nbrown = 274), in the blue tit RNL chromaticity space. Mean and 95% confidence intervals are shown for green (a) and brown (b) natural backgrounds, under two light levels (10 and 1 cd m−2, from top to bottom, represented by cliparts on the left-hand side), based on 1000 bootstrapped replicates per comparison. Each light type is represented by a different colour. The coloured bands represent putative thresholds for colour discrimination (Delta-S between 0.5 and 1.5). Source data are provided as a Source Data file.