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Research Article

Bats' Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds

  • Ana G. Popa-Lisseanu mail,

    To whom correspondence should be addressed. E-mail: anapopa@ebd.csic.es

    Affiliation: Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain

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  • Antonio Delgado-Huertas,

    Affiliation: Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain

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  • Manuela G. Forero,

    Affiliation: Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain

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  • Alicia Rodríguez,

    Affiliation: Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain

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  • Raphaël Arlettaz,

    Affiliations: Division of Conservation Biology, Zoological Institute, University of Bern, Bern, Switzerland, Swiss Ornithological Institute, Valais Field Station, Nature Centre, Salgesch, Switzerland

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  • Carlos Ibáñez

    Affiliation: Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain

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  • Published: February 14, 2007
  • DOI: 10.1371/journal.pone.0000205

Reader Comments (7)

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Perching Questions from Lab Group Discussion of Popa-Lisseanu et al. 2007

Posted by matina1 on 29 Sep 2008 at 17:02 GMT

Given that N. lasiopterus catches songbirds on the wing, what is the evidence, other than the comparative evidence within the Vespertilionidae and Pipistrellini that N. lasiopterus does not perch while consuming the prey?


RE: Perching Questions from Lab Group Discussion of Popa-Lisseanu et al. 2007

anapopa replied to matina1 on 25 Oct 2008 at 16:06 GMT

N. lasiopterus not only is a Pipistrellini, but it is also “the typical” Pipistrellini, both morphologically and in echolocation patterns. Two other evidences are mentioned in Ibáñez et al. 2001. First, none of the 170 mist-netted individuals was ever carrying a prey, be it large or small, insect or bird, contrary to what we would expect in a species that perches. Currently the number of individuals that we have mist-netted is much larger, and the results are still the same. Second, Ibáñez et al. 2001 collected feces and all other remains falling from a colony that roosted in 3 palm trees during 7 months. No discarded prey remains (insects or birds) were ever found under the colony. Such remains can be found under roosts that are used by bats as perches. From 2001 until now, we have also been collecting feces intermittently in several roosts and examining the ground under the bat roosts, and still we never found non-eaten prey remains.
We could argue that the palm trees are diurnal roosts but that the bats would be perching somewhere else during the night. However, we have radiotracked 25 individuals and, when making a nocturnal rest between two foraging bouts, the bats always returned to the diurnal roosts. No nocturnal roosts different than the diurnal roosts were ever found. Our radiotracking data shows that giant noctules forage over very large distances of many tens of kilometers, mostly over non-forested areas, and they do not use stable individual territories. This is contrary to the typical foraging behavior of perching bats.
We have studied the flight behavior of giant noctules with a tracking radar (data still unpublished). The bats flew at great heights (over 300 m and frequently over 1000 m), which is also not consistent with the use of perches.
The other aerial-hawking carnivorous bat, Ia io (Thabah et al. 2007) hasn’t been seen transporting prey either and no prey remains have ever been found inside its cave roosts. It is also a Vespertilionidae, but it belongs to the group Nycticeiini (not a Pipistrellini) and has thus evolved independently of N. lasiopterus.