A preliminary assessment of potential health and genetic impacts in releasing confiscated passerines into the wild: a reduced-risk approach

CRUZ, CLAUDIO E. F.; FUNKLER, GUSTAVO R. ; ZANI, ANDRÉ L. ; CARNIEL WAGNER, PAULO G. ; ANDRETTA, INES ; SEGURA, LUCIANO N.; FAGUNDES, NELSON J.

Frontiers in Veterinary Science

Frontiers Media S.A.

Año: 2021 vol. 8 p. 679049 - 679049

2297-1769

The illegal capture and trade of wild birds have long been threats to biodiversity. The rehabilitation and release of confiscatedanimals may be a useful conservation tool in species management. However, differences between populations regarding health(e.g. different pathogens) and adaptation (e.g. local adaptation) must be taken into account, since both can negatively impact therecipient population. In this pilot study, we used two of the most illegally trafficked Brazilian wild passerine species, namely thered-crested cardinal (Paroaria coronata) and green-winged saltator (Saltator similis) as case studies and assessed some of thehealth threats that the release of confiscated passerines may pose to free-living birds. We also investigated the level of differencein mitochondrial genetic structure among populations living in different ecoregions. Blood, feces, and oropharyngeal swabs fromconfiscated (n=115) and free-living (n=120) passerines from the release sites were tested for the Newcastle disease virus,Salmonella spp., and Mycoplasma gallisepticum. These are considered major avian diseases by the Brazilian National Avian HealthProgram. We analyzed mtDNA to study the difference in genetic structure between populations using samples from 127 free-livingpasserines. We found no evidence of the Newcastle disease virus or Salmonella spp. in confiscated or free-living passerines fromeither species. However, the levels of infection with M. galissepticum detected in our study for red-crested cardinals and greenwingedsaltators calls for a high degree of caution in captive release programs. The difference in genetic structure betweenpopulations occurring in different regions was low, and was not significant between those from the Pampa/Subtropical Grasslandsregion. These results suggest that it may be possible to establish a cost-effective and sensitive protocol for releasing confiscatedsongbirds, provided that further genome-wide studies indicate that the functional genetic diversity among (at least some of the)populations is also low.