Between the years 2022 and 2023, 62 red kite (Milvus milvus) nestlings were translocated from England to Spain to bolster declining populations in mainland Europe as part of a wider conservation initiative. Health examinations were undertaken by veterinarians ahead of translocation, including examination of hematology and biochemistry parameters from blood samples. This study aimed to establish reference values for these parameters in nestling red kites for use in future translocations or for other clinical purposes. All individuals included in the analysis were clinically healthy at the time of sampling. Biochemical reference intervals were comparable to published values for other Accipitridae, although differences in hematology were noted: PCV was generally lower; and WBC counts higher than (up to triple) those reported for related species of a similar age. It is hypothesized that these differences reflect species variations or the effects of the stress of recent capture on the immune system of the red kites. A Leucocytozoon species was identified on blood smears of six of the red kites. The reference intervals presented in this study are representative of free-living red kite nestlings in England that have recently been captured for conservation translocation purposes.