Influence of logging on nest density and nesting microsites of cavity-nesting birds in the subtropical forests of the Andes

Abstract

Birds select nesting sites with certain characteristics associated with tree age and species that help to prevent or reduce the risk of clutch loss due to predation or unfavourable weather conditions. Logging may reduce the availability of trees and their related features thatmay be important for cavity nesters. Thus, the aim of this study is to evaluate the effect of logging on nest density, nesting microsite and nest success of cavity nesting birds at Piedmont forests of northwestern Argentina.We monitored these variables at different logged and unlogged sites during four consecutive reproductive seasons and analysed them using univariate analysis and generalized linear models. The main results indicate that logging reduces nest density and changes the characteristics of the nesting microsites.We found that nest success was greater in cavities located higher above the ground and found no evidence of lower nest success at logged sites. This study suggests the need for forest management actions aimed at increasing nesting sites for cavity-nesting birds. For this purpose, management should be focused on the retention of old trees with a diameter >50 cm (both living and dead). The use of reducedimpact logging techniques or forest certifications (e.g. Forest Stewardship Council) could provide alternatives in subtropical forests, as these forestry practices can ensure tree abundance and richness, providing features suitable for cavity-nesting birds (e.g. tree diameter, cavity size and height).