<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>A sample of 73 dry, well-preserved skulls was studied, representing various species of raptors with different foraging strategies. The sample included <italic>Accipiter nisus</italic> (n = 15), <italic>Buteo buteo</italic> (n = 13), <italic>Gyps fulvus</italic> (n = 24) and <italic>Neophron percnopterus</italic> (n = 5), <italic>Bubo bubo</italic> (n = 16) and <italic>Tyto alba</italic> (n = 2). Geometric morphometric methods were used to detect orbital asymmetries. On digital pictures of each skull side, a set of 16 semi-landmarks and two landmarks were located in order to describe the orbital ring. The variables were analysed based on Generalized Procrustes analysis. The morphometric data showed that the orbital asymmetry of raptors differed significatively between species, although directional asymmetry (e.g. left orbita systematically more developed than the right) appeared not to be correlated with orbital size. This indicates that larger orbitas do not lead to greater asymmetry. Differences between species should rather be explained by their foraging strategies and degree of visual obstruction in their natural environment.</p>
</abstract>

A sample of 73 dry, well-preserved skulls was studied, representing various species of raptors with different foraging strategies. The sample included Accipiter nisus (n = 15), Buteo buteo (n = 13), Gyps fulvus (n = 24) and Neophron percnopterus (n = 5), Bubo bubo (n = 16) and Tyto alba (n = 2). Geometric morphometric methods were used to detect orbital asymmetries. On digital pictures of each skull side, a set of 16 semi-landmarks and two landmarks were located in order to describe the orbital ring. The variables were analysed based on Generalized Procrustes analysis. The morphometric data showed that the orbital asymmetry of raptors differed significatively between species, although directional asymmetry (e.g. left orbita systematically more developed than the right) appeared not to be correlated with orbital size. This indicates that larger orbitas do not lead to greater asymmetry. Differences between species should rather be explained by their foraging strategies and degree of visual obstruction in their natural environment.

Comparison of orbital asymmetries among some raptor species: “when size does not matter”

Raptor Journal

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

A sample of 73 dry, well-preserved skulls was studied, representing various species of raptors with different foraging strategies. The sample included...

Comparison of orbital asymmetries among some raptor species: “when size does not matter”

Published Online: Apr 30, 2021

Page range: 23 - 27

Received: Jul 23, 2020

Accepted: Oct 29, 2020

DOI: https://doi.org/10.2478/srj-2020-0005

Keywords
Accipitriformes, directional asymmetry, fluctuating asymmetry, orbital shape, Strigiformes, vision

© 2020 Pere M. Parés-Casanova et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Comparison of orbital asymmetries among some raptor species: “when size does not matter”

Published Online: Apr 30, 2021

Page range: 23 - 27

Received: Jul 23, 2020

Accepted: Oct 29, 2020

DOI: https://doi.org/10.2478/srj-2020-0005

KeywordsAccipitriformes, directional asymmetry, fluctuating asymmetry, orbital shape, Strigiformes, vision

© 2020 Pere M. Parés-Casanova et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
Accipitriformes, directional asymmetry, fluctuating asymmetry, orbital shape, Strigiformes, vision