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Aves, 52/3 | 2015 | 129-151

  Population monitoring of Woodcock Scolopax rusticola during the breeding season in the Canton of Neuchâtel (Switzerland) over the years 2001-2010
Blaise Mulhauser & Jean-Lou Zimmermann

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Article summary

The population of Woodcock in the canton of Neuchâtel (Switzerland) has been evaluated by recording the songs of male birds during roding activity at 32 listening points over a period of ten years. It proved possible to recognise and to count individual birds by estimating a number of acoustic parameters. As a complement to this work an intense search for Woodcock was performed at 333 listening points distributed over the whole forested area of the canton (300 km²). The result is a comprehensive map of the species during the breeding season.The annual monitoring shows that populations were stable for a period of 6 years (2001-2006) at a total population of between 33 and 37 males. In 2007, a dramatic increase in the number of birds (49 males) was followed by an equally dramatic fall to 26 to 28 males in 2008. In 2009 and 2010 the population settled at the lowest number since 2008 (27 to 31 males). The population trend over the decade as a whole was negative; several roding areas have been abandoned. The study enables the methodology to be assessed and compared with the more generally used method of population census, i.e. by simple count of contacts at a given listening point – as used, for example, in France and in French-speaking Switzerland. The results demonstrate that when analysis was performed across all listening points, there was a very strong correlation between the mean number of males present and the mean number of contacts. It is concluded that census by a simple count of contacts is a valid methodology for estimating population trends.Support for this conclusion is provided by the remarkable similarity over the period 2001-2008 between the curves for Neuchâtel and for the survey in France. It appears that the local populations of this migratory species are subject to factors which operate over large geographic areas. On the other hand, a simple count of contacts is not effective for making a detailed census of the individuals present on a roding area; for this, bioacoustic monitoring is required. At the end of this article we provide some recommendations for such a procedure.

Contact

  • Blaise Mulhauser
    SORBUS, Association pour la sauvegarde des oiseaux rares et des boisements utiles à leur survie
    Av. des Cadolles 4a, 2000 Neuchâtel, Suisse
    Jardin botanique de Neuchâtel, Pertuis-du-Sault 58, 2000 Neuchâtel
    blaise.mulhauser(at)unine.ch

    Jean-Lou Zimmermann
    jean-lou.zimmermann(at)net2000.ch

     

     

Articles on the same species

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Scolopax rusticola

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