Figure 1

Box plots of log ₁₀ -transformed standard deviation and skewness in brain mass in relation to whether a bird species was urbanized or not. (A) Box plots of log₁₀-transformed standard deviation in brain mass in relation to whether a bird species was urbanized or not. (B) Box plots of skewness in brain mass in relation to whether a bird species was urbanized or not. Box plots show median, quartiles, 5- and 95-percentiles and extreme observations.