title: Bats' conquest of a formidable foraging niche: the myriads of nocturnally migrating songbirds.
abstract: Along food chains, i.e., at different trophic levels, the most abundant taxa often represent exceptional food reservoirs, and are hence the main target of consumers and predators. The capacity of an individual consumer to opportunistically switch towards an abundant food source, for instance, a prey that suddenly becomes available in its environment, may offer such strong selective advantages that ecological innovations may appear and spread rapidly. New predator-prey relationships are likely to evolve even faster when a diet switch involves the exploitation of an unsaturated resource for which few or no other species compete. Using stable isotopes of carbon and nitrogen as dietary tracers, we provide here strong support to the controversial hypothesis that the giant noctule bat Nyctalus lasiopterus feeds on the wing upon the multitude of flying passerines during their nocturnal migratory journeys, a resource which, while showing a predictable distribution in space and time, is only seasonally available. So far, no predator had been reported to exploit this extraordinarily diverse and abundant food reservoir represented by nocturnally migrating passerines.
authors.affiliation: Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain. anapopa@ebd.csic.es
authors.forename: Ana G
authors.initials: AG
authors.lastname: Popa-Lisseanu
authors.forename: Antonio
authors.initials: A
authors.lastname: Delgado-Huertas
authors.forename: Manuela G
authors.initials: MG
authors.lastname: Forero
authors.forename: Alicia
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Raphaël
authors.initials: R
authors.lastname: Arlettaz
authors.forename: Carlos
authors.initials: C
authors.lastname: Ibáñez
mesh_terms: D025041:Animal Migration; D000818:Animals; D002247:Carbon Isotopes / Q000097:blood; D002685:Chiroptera / Q000097:blood / Q000502:physiology*; D002940:Circadian Rhythm; D004032:Diet; D005247:Feeding Behavior / Q000502:physiology*; D007313:Insecta; D009587:Nitrogen Isotopes / Q000097:blood; D011235:Predatory Behavior / Q000502:physiology*; D012621:Seasons; D020308:Songbirds
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes