Does the use of playback affect the estimated numbers of red–legged partridge Alectoris rufa?

P Tizzani,E Negri,F Silvano,G Malacarne,P G Meneguz

doi:10.32800/abc.2012.35.0429

Abstract

The red–legged partridge Alectoris rufa lives in a situation of potential conservation risk for its long–term preservation in Italy as its habitat is increasingly threatened by the disappearance of traditional agriculture–related environments. In such a situation, it is important to use effective and appropriate monitoring methods to assess population changes over time and to identify potential conservation threats. The objective of this study was to evaluate the effectiveness of the playback method to estimate the density of calling males. We compared playback method with spontaneous calling of males at dawn and direct observations along transects. The results on raw count data of playback counts revealed a strong underestimation rate compared to the method that gave the best results: count of spontaneous calls at dawn. Our study provides a critical evaluation of a method that is widely used even though data about its effectiveness are scarce. Our data do not evaluate detection probability of the three methods. Our aim was only to evaluate which methods give the best results in term of population size estimation under the same field condition (same population density, same period, same monitoring area). The results raise some doubts about the ability of the playback method to monitor red–legged partridge populations. The implications of our results for red–legged population management are discussed.

Highlights

The red–legged partridge Alectoris rufa is widely distributed in Europe, with natural populations reported in Portugal, Spain, Andorra, France and Italy (Birdlife International, 2009)
Red–legged partridge belong to the Galliform order, an order that is highly threatened, with 27% of species threatened with extinction, and about 60% of unthreatened species in decline (Rands, 1992; Potts & Aebischer, 1995; UNEP–WCMC, 2001)
The first study area was the typical Italian habitat for red–legged partridge, the traditional agricultural landscape. This habitat is seriously threatened by land abandonment and by the extension of wooded areas (Falcucci et al, 2006). This area is very important for conservation management of partridges because it is the only area in Italy where red–legged partridge populations are non–hybridized (Negri et al, in prep.)

Summary

Introduction

The red–legged partridge Alectoris rufa is widely distributed in Europe, with natural populations reported in Portugal, Spain, Andorra, France and Italy (Birdlife International, 2009). In Italy, in particular, the species showed a dramatic decline; it lives in a situation of potential conservation risk (Meriggi et al, 2007) for its long–term preservation as its habitat is increasingly threatened by the disappearance of traditional agriculture–related environments (Falcucci et al, 2006). In such a situation, it is important to use effective monitoring tools to assess population changes over time and to identify potential conservation threats (Kasprzykowski & Goławski, 2009). This method is widely used to monitor many secretive species (e.g. Conway et al, 1993; Zuberogoitia & Campos, 1998; Brambilla & Rubolini, 2004) and in particular for Galliformes (e.g. Evans et al, 2007; Serrani et al, 2005; Cattadori et al, 2006; Amici et al, 2009)

Objectives

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Results

Conclusion