[Ocurrence of Ornithonyssus bursa (Berlese, 1888) (Acari: Macronyssidae) on Megascops choliba (tropical screech-owl) and Pitangus sulphuratus (great kiskadee) nestlings in the Rio Grande do Sul State, Brazil].

The Center for Rehabilitation of Wildlife and Center for Selection of Wild Animal of the Federal University of Pelotas has attended two nestlings of Megascops choliba (tropical screech-owl) (Strigiformes - Strigidae) and two of Pitangus sulphuratus (great kiskadee) (Passeriformes - Tyrannidae) heavily parasitized by mites, in May 2005 and December 2006, respectively. The nestlings and the nest of P. sulphuratus were collected in the Pelotas urban area after severe storms. The mites were removed, clarified in lactofenol, permanently mounted in Hoyer's medium and identified as Ornithonyssus bursa (Acari - Macronyssidae). Megascops choliba and Pitangus sulphuratus are reported as host of Ornithonyssus bursa in Rio Grande do Sul State, Brazil.