Armed Rollers: Does Nestling’s Vomit Function as a Defence against Predators? Parejo, Deseada Avilés, Jesús M. Peña, Aránzazu Sánchez, Lourdes Ruano Díaz, Francisca Del Carmen Zamora Muñoz, Carmen Martín-Vivaldi Martínez, Manuel Lorenzo Birds Dogs Meat Plant defenses Plant-herbivore interactions Predation Secretion Vomiting Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus), expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, its chemical composition and deterrent effect on a mammal generalist predator. We also hypothesized that nestling rollers, as their main prey (i.e. grasshoppers) do from plants, could sequester chemicals from their prey for their use. Grasshoppers, that also regurgitate when facing to a threat, store the harmful substances used by plants to defend themselves against herbivores. We found that nestling rollers only vomit after being grasped and moved. The production of vomit depended on food consumption and the vomit contained two deterrent chemicals (hydroxycinnamic and hydroxybenzoic acids) stored by grasshoppers and used by plants to diminish herbivory, suggesting that they originate from the rollers’ prey. Finally, we showed for the first time that the oral secretion of a vertebrate had a deterrent effect on a model predator because vomit of nestling rollers made meat distasteful to dogs. These results support the idea that the vomit of nestling rollers is a chemical defence against predators. 2014-03-27T14:05:19Z 2014-03-27T14:05:19Z 2013 info:eu-repo/semantics/article Parejo, D.; et al. Armed Rollers: Does Nestling’s Vomit Function as a Defence against Predators?. Plos One, 8(7): e68862 (2013). [http://hdl.handle.net/10481/31142] 1932-6203 doi: 10.1371/journal.pone.0068862 http://hdl.handle.net/10481/31142 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Public Library of Science (PLOS)