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The evolutionary relationship among beak shape, mechanical advantage, and feeding ecology in modern birds

Navalón, Guillermo; Bright, Jen A.; Marugán‐Lobón, Jesús; Rayfield, Emily J.


Guillermo Navalón

Jesús Marugán‐Lobón

Emily J. Rayfield


Extensive research on avian adaptive radiations has led to a presumption that beak morphology predicts feeding ecology in birds. However, this ecomorphological relationship has only been quantified in a handful of avian lineages, where associations are of variable strength, and never at a broad macroevolutionary scale. Here, we used shape analysis and phylogenetic comparative methods to quantify the relationships among beak shape, mechanical advantage, and two measures of feeding ecology (feeding behavior and semiquantitative dietary preferences) in a broad sample of modern birds, comprising most living orders. We found a complex relationship, with most variables showing a significant relationship with feeding ecology but little explanatory power. For example, diet accounts for less than 12% of beak shape variation. Similar beak shapes are associated with disparate dietary regimes, even when accounting for diet‐feeding behavior relationships and phylogeny. Very few lineages optimize for stronger bite forces, with most birds exhibiting relatively fast, weak bites, even in large predatory taxa. The extreme morphological and behavioral flexibility of the beak in birds suggests that, far from being an exemplary feeding adaptation, avian beak diversification may have been largely contingent on trade‐offs and constraints.

Journal Article Type Article
Publication Date Dec 21, 2018
Journal Evolution
Print ISSN 0014-3820
Electronic ISSN 1558-5646
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 73
Issue 3
Pages 422-435
APA6 Citation Navalón, G., Bright, J. A., Marugán‐Lobón, J., & Rayfield, E. J. (2018). The evolutionary relationship among beak shape, mechanical advantage, and feeding ecology in modern birds. Evolution, 73(3), 422-435.


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