Avian species pose risks for transmitting viruses, including avian circoviruses, that could be a threat for conservation and introduction into commercial flocks. This study investigated the presence of circovirus in 81 avian species from different regions of Brazil, including the northwest region of São Paulo and the coast of Paraná. Blood samples and oropharyngeal, cloacal, and other organ swabs were collected. The samples were extracted and screened using nested PCR for the replicase gene. In positive cases, the samples were sequenced. Regarding the results, a total of 1528 swab samples were collected from 601 birds, of which 24 (4%, 95% CI: 2.4–5.6) tested positive for various circovirus subtypes. Most positive birds (92%, 22/24) were from the northwest region of São Paulo, mainly from the city of São José do Rio Preto (54%, 12/22). The study also identified the presence of circovirus subtypes in avian families that were not previously described. Furthermore, the presence of raven circovirus in the blood sample of a Nyctibius griseus (potoo), suggests the possibility of a new carrier of the virus. Ultimately, the findings underscore the complexity of the viral ecology of avian circoviruses, highlight the necessity of enhancing future studies, and emphasize the need to support health assessment of wildlife, including marine birds.