Abstract
Resource polymorphism refers to individuals from the same population foraging in alternative habitats or on alternative food. Food specialization can be associated with adaptations such as colour polymorphism, with pale and dark colours conferring differential camouflage in different habitats. Pale and dark-reddish pheomelanic Barn Owls (Tyto alba) forage on different prey species in closed and open habitats, respectively. We show here that darker-reddish owls have heavier stomach content when found dead, and their 5th secondary wing feather is more deeply anchored inside the integument. These correlations suggest that their feathers bend less when flying, and that darker-reddish Barn Owls are able sustain more intense flying than their paler conspecifics.
Zusammenfassung
Phäomelanin-Färbung bei Schleiereulen korreliert mit Merkmalen der Flugstrategie
Ressourcen-Polymorphismus beschreibt Individuen derselben Population, die ihre Nahrung in alternativen Habitaten suchen oder sich von anderem Futter ernähren. Nahrungsspezialisierung kann einhergehen mit Anpassungen wie einem Farb-Polymorphismus, bei dem helle und dunkle Farben unterschiedliche Tarnung in unterschiedlichen Habitaten gewähren. Helle und dunkel-rötliche phäomelanische Schleiereulen (Tyto alba) bejagen jeweils andere Beutearten in geschlossenem beziehungsweise offenem Habitat. Hier zeigen wir, dass die dunkel-rötlichen Eulen einen schwereren Mageninhalt haben, und dass ihre fünfte Armschwinge tiefer im Integument verankert ist. Diese Korrelationen deuten darauf hin, dass ihre Federn sich im Flug weniger biegen, und dass dunklere rötliche Schleiereulen einen kräftigeren Flug aufrecht erhalten können, da ihre helleren Artgenossen mit schwerem Mageninhalt tot aufgefunden wurden.
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Acknowledgments
We thank Kobi Meyrom, Amir Ezer, and Shay Halevi for assistance in collection carcasses and Naomi Paz for editorial assistance. The study was financed by the Swiss National Science and Addax-Oryx Foundations.
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Communicated by L. Fusani.
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Charter, M., Leshem, Y., Izhaki, I. et al. Pheomelanin-based colouration is correlated with indices of flying strategies in the Barn Owl. J Ornithol 156, 309–312 (2015). https://doi.org/10.1007/s10336-014-1129-6
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DOI: https://doi.org/10.1007/s10336-014-1129-6