Density estimates of passerine bird species in Tenerifean coastal scrub using two different methods (Canary Islands)

Abstract

Attempts to estimate the population density of passerine bird species were made in good and protected areas of Tenerifean coastal scrub using two different methods, (i.e. territory mapping and line transect). Independently of the method used, Anthus berthelotii had the highest density, Sylvia conspicillata was less abundant and Lanius meridionalis was scarce. Phyllocopus canariensis and Serinus canarius had intermediate values but Bucanetes githagineus was so scarce that no density estimate was possible. Line transect overestimated the density estimate for Anthus berthelotii. Neither of the two techniques used was perfectly suitable for reliably sampling all passerines in the Tenerifean coastal scrub and therefore it is recommended that future estimates should be made with more precise methods, that allow to measure the error of the estimate and that account for detectability (e.g. Distance sampling).