Adverse effects of radiotransmitters and handling are major concerns during radiotracking studies, especially in avian species. Fourteen out of 46 (30.4%) juvenile red-legged partridge (Alectoris rufa) trapped using hand-held nets and marked with necklace radiotags during a study in southern Spain died within a few hours after capture. We studied the affected birds and compared data from postmortem examination, blood chemistry, biometry, and meteorology on capture days to identify risk factors related to the deaths. The affected partridge had high creatine kinase plasma levels. Postmortem examination confirmed that the deaths had been due to self-injury, capture myopathy (CM), or both. Distribution of lesions indicated that struggling with the transmitter could have exacerbated CM caused by trapping and handling. There was no effect due to bird size or weight, but deaths were related to capture days with lower mean temperatures and higher humidity. The consideration of combined risk factors such as climate, capture method, and radiotag type may deserve more attention regarding capture and radiotagging techniques, especially in juvenile partridge.