Geometric morphometrics reveal interspecific and sexual differences in bill morphology in four sympatric planktivorous petrels

Variation in morphological structures may indicate the existence of ecological differences between species or sexes. In birds, the bill is one of the structures most affected by selection pressures because it is directly involved with several biological functions, particularly the acquisition of food. In this study, we combined geometric morphometrics and comparisons of linear measurements to assess the presence of sexual dimorphism and...