Farmland birds, including breeding waders, have declined across Europe. One frequently advocated strategy to facilitate population recovery is using agri-environment schemes (AES) to improve vegetation structure. A key example is cutting dense rush Juncus to open the sward which aims to increase the abundance of wading birds, for example by improving foraging conditions. Effects on breeding success are, however, unknown. This is a critical knowledge gap as high nest and chick predation rates are a key driver of wader declines. For wader species that nest across a range of sward structures, e.g. Eurasian curlew Numenius arquata and common snipe Gallinago gallinago, converting denser swards to more open ones may reduce opportunities for nest concealment and thus increase predation risk. Due to the difficulties of locating large numbers of wader nests, we assess rush management impacts on nest predation risk using artificial wader nests (n = 184) in two upland areas of England, using fields in which rush is managed according to AES prescriptions (treatment; n = 21) or un-managed (control; n = 22) fields. Daily nest predation rates (DPRs) were twice as high in treatment (0.064 day^-1) than control fields (0.027 day^-1). Within treatment fields, DPRs were twice as high for nests in cut rush patches (0.108 day^-1) than in uncut rush (0.055 day^-1). Modelling links higher DPRs associated with rush cutting to the resultant shorter and less dense vegetation. Our results highlight the need to assess how AES prescriptions that alter vegetation structure impact all aspects of the target species’ fitness and thus determine population recovery. Studies using real wader nests should test whether AES rush management inadvertently creates an ecological trap by altering vegetation structure, and identify the sward structure and configuration that optimises trade-offs between foraging conditions and nest predation risk.

Artificial wader nest data

ArtificialNestData.xlsx

Dataset for analyses of daily nest predation rates of artificial waders nests in treatment fields with rush management and control fields without rush management. Each row is an individual nest. Metadata is available in a second sheet in the ArtificialNestData.xlsx file. The mean number of corvids and the mean number of avian predators were calculated from the AvianPredData.xlsx file. 

Avian predator survey data

AvianPredData.xlsx

Dataset for analyses of avian predator abundance. Each row is an individual visit to a field with the number of avian predators observed. The sum of the number of corvids and the sum of the number of avian predators are provided. Metadata is available in a second sheet in the AvianPredData.xlsx file.