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Here I report on a small scale study aimed at generating baseline information on the immune response of wild red-fronted parakeets, as assessed by blood cell counts, and subcutaneous challenge with phytohaemagglutinin (PHA), a mitogen that causes swelling at the point of injection. Eleven parakeets captured in mist-nets were injected into the right patagium with 0.5 mg PHA and the resulting swelling measured at 6 hours post-injection. Prior to PHA challenge, feather and blood samples were collected for detection of beak and feather disease virus and Plasmodium. Blood smears were also prepared for blood cell counts. Swelling occurred 6 hours post-injection in all but one individual, which tested positive for beak and feather disease virus. In this individual, no measurable swelling was detected. Estimated leucocyte counts, lymphocyte counts and heterophil counts of the same individual were similar to values of beak and feather disease virus negative individuals. Plasmodium DNA was detected in 2 individuals and their immune response was similar to that of parakeets testing negative for both beak and feather disease virus and Plasmodium. Estimated leucocyte counts, lymphocyte and heterophil counts did not differ between Plasmodium infected and non-infected individuals. The fact that the only individual testing positive for beak and feather disease virus showed no immune response to PHA challenge suggests increased susceptibility to other pathogenic infections. Although preliminary, this study highlights the potential damaging consequences of the accidental introduction of beak and feather disease virus in conservation programmes of threatened New Zealand parrots, some of which might already suffer from decreased immunocompetence resulting from reduced genetic diversity.