Fig. 4
From: Song divergence indicates an unclear relationship between the Neotropical and Nearctic Horned Larks
Differences in the playback response to the Nearctic, Neotropical, and control (Rufous-collared Sparrow) stimuli. a Boxplot of each variable evaluated. b Boxplot of the response intensity variable (PC1). Lower PC1 values indicate a stronger response as it reflects a faster and closer approach with more reply vocalizations. Also, we show the PC1 vs PC2 scatterplot. The ellipses of the scatter plot were calculated automatically in the R software using the option of concentration ellipses (.5.8 degree). ** = p < 0.005; *** = p < 0.001