Supplementary feeding of European Turtle Doves Streptopelia turtur: provisioned field plots are preferentially used and do not have higher frequency of the parasite Trichomonas gallinae

Field plots provisioned with a supplementary seed mix during summer attracted European Turtle Doves and other farmland birds, and exhibited only a low incidence of the parasite Trichomonas gallinae. To test whether Turtle Doves and other granivorous birds use field plots provided with supplementary seed, and whether use of these plots increased exposure to T. gallinae. Supplementary seed mix was provided at two rates (3 and 6 kg per 250 m2 plot) weekly at 37 sites in the spring and summer of 2016 and 2017. Provisioned plots, and similar (but unprovisioned) control areas, were surveyed for Turtle Doves and other birds. Soil swab samples were also taken and analysed for the presence of T. gallinae using a standard polymerase chain reaction procedure. Turtle Doves were much more likely to be recorded on provisioned plots than on unprovisioned control areas. Maximum counts of an aggregate of seven other granivores of conservation interest (European Greenfinch Chloris chloris, Common Linnet Linaria cannabina, Eurasian Tree Sparrow Passer montanus, House Sparrow P. domesticus, Common Reed Bunting Emberiza schoeniclus, Corn Bunting E. calandra and Yellowhammer E. citrinella) were significantly higher on provisioned plots than on control areas. Positive samples for T. gallinae were rare on provisioned plots and unprovisioned areas (eight of 474 samples across both years). Samples classified as ambiguous (due to the presence of genomic DNA that could not be definitively ascribed to T. gallinae) or positive were equally likely on provisioned plots and unprovisioned areas, but were more likely at sites where European Greenfinches were recorded. Supplementary seed provisioning in summer can attract foraging Turtle Doves with only a low risk of exposure to T. gallinae on the feeding areas.