Ecological intensification has emerged as a new paradigm for agricultural production that promotes ensuring the provision of ecosystem services mediated by biodiversity to enhancing crop yield. Birds provide critical ecosystem services for agricultural production such as biological pest control, a role that has been recently highlighted. However, agriculture itself has been one of the main causes of global biodiversity loss, including the recent decline in bird populations, particularly the insectivorous guild. Therefore, agricultural management solutions have arisen to maintain insectivorous bird populations within crops, such as the provision of nesting sites using nest boxes. Here, we report the results of a sentinel prey experiment, to assess improvements in pest control due to bird consumption in crops enhanced with nest boxes. The experiment was conducted in five commercial vineyards located in central Chile. At each vineyard, 2 plots were selected (ea. 4 ha); in one of them, 21 nest boxes (i.e., treatment plot) were randomly installed during winter, while the other was used as control. Nest box occupancy was monitored during the breeding season in spring. A sentinel prey experiment was set up in the two plots at each vineyard, consisting of ten plastic containers randomly installed at canopy height (ea. 1.5 m), in which 5 larvae of the Codling moth (Cydia pomonella) offered as prey for 8 hours. The number of larvae removed was used as a response variable in a GLMM to analyze the effect of nest boxes across vineyards.
Results/Conclusions
We found significantly more prey removal due to bird consumption in the plots where nest boxes were installed (mean 3.08 ± 0.17 SE) compared to the control plots (mean 2.04 ± 0.22 SE; P=0.00121). Interestingly, in one of these vineyards in which prey removal was too low, there were no birds occupying nest boxes. Nest boxes were only occupied by insectivorous species, among which the Chilean swallow (Tachycineta leucopyga), the House wren (Troglodytes aedon) and the Thorn-tailed rayadito (Aphrastura spinicauda). Although this research only considers one study season, our results highlight the contribution of insectivorous birds as pest control agents in crops. This kind of ecosystem service provided by birds is of high value for agriculture and encourages the adoption of management practices aligned with the ecological intensification paradigm at the farm and landscape level to contribute to avian biodiversity conservation.