Since a few years acute mortality in late summer has been observed in trushes (Turdinae) kept in aviaries by bird ringers. Only fieldfares and redwings are affected. Swelling and darkening of spleens and livers are the most conspicious lesions. Sexual and asexual stadia of Plasmodium were detected cytologically in blood smears. Schizonts were found in impression smears of liver, spleen, and kidney. Incidence and pathogenesis of haematozoal infections in trushes are reviewed and compared with our findings.