Does Reed Bunting (Emberiza schoeniclus) predict the risk of nest predation when choosing a breeding territory? An experimental study

Abstract

Increasing evidence suggests that birds minimize the risk of nest predation by preferentially settling in territories with low predator encounter rate. However, little is known about whether they are also able to assess the actual risk of nest predation at the time of habitat occupancy and choose their breeding territories accordingly. Here, we tested this prediction experimentally, using artificial nests placed in 29 Reed Bunting territories and 29 in randomly-selected non-territories located in the same habitat. Simultaneously, we estimated the spatial distribution of the main Reed Bunting nest predator in the study area, viz. the Marsh Harrier. Nests located in Reed Bunting territories were predated less frequently (14%) than were nests placed in non-territories (41%), and this was also associated with the relative abundance of Marsh Harriers in territories (average 3.7) and in nonterritories (average 5.8). These findings support the hypothesis that Reed Buntings may be capable of choosing their territories according to the actual predation risk.