Monitoring communities of small birds: a comparison between mist-netting and counting

Capsule Counting and mist-netting provided different estimates of abundance. Aims To compare the efficiency, constraint and bias of mist-netting versus line transects for the estimation of species richness and abundance of passerines. Methods Mist-nets (126 linear metres) placed crossing a 420 m-long hedgerow line, open for four hours starting at dawn, four days per month from June 2006 to May 2007. During this same period, we conducted a transect parallel to a 1.3-km hedgerow line, four times per month. Results Estimation of species richness did not vary between methods, even when controlling for ecological groups, whereas the abundance estimations did vary. Conclusions Overall, line transects are better than mist-netting for estimating species richness and abundance since they are less costly, less invasive, and less time-consuming. However, if fine ecological analyses are required, including species abundance, mist-netting is preferred for solitary passerines that feed on insects and forage in the foliage, and line transects are better for gregarious passerines that feed on seeds or forage on the ground.