Variation among species and populations in bill shape and size in three planktivorous petrels

• Published in: Marine Biology
• Main Authors: Laranjeiro, Maria, Farré, Marc, Phillips, Richard, Quillfeldt, Petra, Bonadonna, Francesco, Gémard, Charlene, Daigre, Maximiliano, Suazo, Cristián, Barbraud, Christophe, Navarro, Joan
• Other Authors: Institute of Marine Sciences / Institut de Ciències del Mar Barcelona (ICM), Consejo Superior de Investigaciones Científicas Madrid (CSIC), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Department of Animal Ecology & Systematics, Justus-Liebig-University Gießen, Germany, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Magister de Recursos Naturales Santiago, Chile, Universidad Católica Andrés Bello, Department of Animal Ecology & Systematics Germany, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Bill morphology; Character displacement; Ecological segregation; Geometric morphometrics; Niche differentiation; Seabirds; [SDE]Environmental Sciences; Antarctic; Kerguelen; Antarc*; Antarctic prion; Pachyptila desolata
• Online Access: https://hal.archives-ouvertes.fr/hal-03652996; https://doi.org/10.1007/s00227-021-04014-7

International audience Morphological variation in biological structures may be driven by genetic and environmental factors, such as inter-and intraspecific competition for resources. In seabirds, although the bill is also involved in vocalization, olfaction, sexual selection and defence, the main drivers of high morphological plasticity in bill size and shape appear to relate primarily to diet and thus to niche differentiation. Here, we combined geometric morphometrics and comparisons of linear measurements as a precise tool for measuring shape variation in anatomical features, to investigate the differences among species and populations (island groups) in bill shape of three planktivorous petrels (Antarctic prion Pachyptila desolata, blue petrel Halobaena caerulea and thin-billed prion Pachyptila belcheri). Fieldwork was carried out in South Georgia (54° 0′ S, 38° 3′ W), Falkland (51° 42′ S, 57° 51′ W), Diego Ramírez (56° 31′ S, 68° 44′ W) and Kerguelen (49° 20′ S, 69° 20′ E) Islands, from 2010 to 2021. Results show that the bills of Antarctic prions were more robust and shorter, appropriate for filtering large amounts of small prey. Blue petrels and thin-billed prions had narrower and longer bills, effective for catching and tearing large single prey. Also, Antarctic prions and blue petrels from Kerguelen had longer and narrower bills than conspecifics from other colonies, which could potentially be explained by geographic variation in diet. In conclusion, prey availability and diversity appear to be important factors influencing variation in bill morphology. This study highlights the utility of geometric morphometrics for investigating bill shape variation in seabirds. Nevertheless, further studies are needed to better understand selective pressures leading to morphological variation of biological structures.