Effects of nest positioning on fledging success in a breeding colony of Passer montanus (Passeridae): a case study in Central Anatolia, Turkey

Abstract Tree sparrows exhibit a range of breeding tactics from nesting in solitary pairs to forming breeding aggregations. We present a case study on the reproductive consequences of nest positioning in a loose breeding colony of Eurasian tree sparrow (Passer montanus) in central Turkey. We tested whether height and centrality of nests, together with their interaction, influenced fledging success in a single breeding season by running a generalized linear mixed-effects model. Nest height did not influence fledging success in a significant way. Also, productivity did not differ relative to the distance from the colony edge. This study provides the first detailed information about the effects of nest location on productivity for tree sparrows outside Continental Europe, and emphasizes the need for further studies on this model species.