Age-Related Variation in Wing Shape Differs between Bird Orders: Implications for Interpretation of the Pointedness Index (C2 Axis) in a Size-Constrained Principal Component Analysis (SCCA)

Abstract

There is a strong relationship between bird wing morphology and flight style. wing shapes are related to manoeuvrability, flight speed, energetic costs during flight and takeoff speed. wing shape differences among species have been frequently studied but differences can also be found within species, between sexes and age groups. Many studies have assessed differences in wing shape between juveniles and adults in different passerine species but little is known about such differences in other bird orders. Performing a Size Constrained Components Analysis (SCCA) and a graphical approximation, we analysed the wing shape of juveniles and adults of eight species, including four passerines and four non-passerines of three different orders. According to a graphical approximation, we observed that wing shape differences between age groups differ among species. In the non-passerine species considered, juveniles have more pointed and concave wings than adults. In contrast, in the four passerine species, juveniles have more rounded wings than adults. However, the results for the C2 axis of SCCA