Three hundred and twenty-two birds belonging to 35 species were live-captured in Reifenstein, Middle Germany, from March to October 2004, to investigate their role as hosts of Borrelia burgdorferi sensu lato and its vector ticks. A total of 141 Ixodes ricinus ticks collected from 53 birds belonging to eight species was investigated for the prevalence of B. burgdorferi by a PCR-RFLP analysis of the OspA gene. Three of these bird species, the blackbird (Turdus merula), the song thrush (T. philomelos), and the bullfinch (Pyrrhula pyrrhula) harboured B. burgdorferi s.l. infected ticks. The prevalence of B. burgdorferi s.l. in the bird-feeding ticks was 25%. The majority of the ticks carried B. garinii (53%), followed by B. valaisiana (28%). In the same region, 256 questing ticks were collected to determine the local Borrelia genospecies diversity in I. ricinus. In all, 15.2% of the ticks which were found positive for B. burgdorferi s.l. contained B. valaisiana (45%) as the most frequent genospecies. The results of the present study indicate an important role of the blackbird and the song thrush in the natural cycle of B. burgdorferi s.l. in Thuringia.