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Abstract Agricultural intensification is a major driver in species declines, with changes in land use resulting in widespread alteration of resource availability. An increase in anthropogenic food resources, alongside decreasing natural resources, has resulted in species undergoing dietary changes that can have important ecological consequences, particularly for declining species. Here we use high‐throughput sequencing to analyze the diet of the migrant European turtle dove (Streptopelia turtur), a species that has experienced significant population decline throughout its European range. We analyze the diet of this species on both breeding and wintering grounds to gain an understanding of resource use throughout the annual cycle and compare areas of more and less intensive agriculture in western and eastern Europe, respectively. We examine associations with body condition, spatiotemporal variation and the source of food (wild or cultivated). We identified 121 taxonomic units in the diet, with significant variation across sampling seasons, and very little overlap between the breeding and wintering seasons, as well as high levels of cultivated food resources in the diet of turtle doves in both breeding and wintering grounds, with the highest proportion of wild seeds in the diet occurring in birds caught in Hungary, where agricultural intensity was lowest. We detected no association between body condition and the consumption of cultivated food resources. We demonstrate the importance of wild resources in birds on the wintering grounds as they approach migration, where body condition increased as the season progressed, concurrent with an increased consumption of wild seeds. These findings indicate the importance of habitats rich in wild seeds and the need to consider food availability on the wintering grounds, as well as the breeding grounds in turtle dove conservation strategies.

Abstract Trichomonas gallinae, a protozoan parasite infecting a wide range of birds, has been a cause for conservation concern since its recognition as an emerging infectious disease, having had notable impacts on several avian species, including causing widespread mortality in greenfinches (Chloris chloris), and chaffinches (Fringilla coelebs), and hindering the recovery of the endangered pink pigeon (Nesoenas mayeri). Horizontal transmission between birds congregating at feeding sites, such as those provided for conservation and species management purposes, is an important driver in the spread of T. galliane. Supplementary feeding is a key conservation intervention for the European turtle dove (Streptopelia turtur), which is declining across its range, driven at least partially by a loss of natural food resources. Due to the link between T. gallinae transmission and supplementary feeding, we consider the prevalence of this parasite among European turtle dove in relation to diet, in the first study to analyze these two factors in the decline of this species together. Using birds sampled from breeding and wintering grounds, the dietary composition of individuals was compared to the presence of T. gallinae, and specific T. gallinae strains. Dietary variation was summarized into two axes using detrended correspondence analysis; neither was associated with the presence of T. gallinae or any specific strains. The proportion of diet accounted for by cultivated seeds did not affect parasite presence, despite the spread of this parasite being associated with supplementary feeding due to an increase in contact between potentially infected and uninfected birds gathering at high densities at feeding sites. Significant dietary overlap was observed between infected and uninfected individuals in all sites, with almost complete dietary overlap being observed in one breeding site. The level of dietary overlap between individuals infected with specific strains fluctuated between sampling seasons, indicating no consistent relationship between diet and infection status.