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Blood parasites in Owls with conservation implications for the Spotted Owl (Strix occidentalis)

January 1, 2008

The three subspecies of Spotted Owl (Northern, Strix occidentalis courina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for Spotted Owls. Although Barred Owls commonly harbor Plasmodium infections, these parasites have not been documented in the Spotted Owl. We screened 111 Spotted Owls, 44 Barred Owls, and 387 owls of nine other species for haemosporidian parasites (Leucocytozoon, Plasmodium, and Haemoproteus spp.). California Spotted Owls had the greatest number of simultaneous multi-species infections (44%). Additionally, sequencing results revealed that the Northern and California Spotted Owl subspecies together had the highest number of Leucocytozoon parasite lineages (n=17) and unique lineages (n=12). This high level of sequence diversity is significant because only one leucocytozoon species (L. danilewskyi) has been accepted as valid among all owls, suggesting that L. danilewskyi is a cryptic species. Furthermore, a Plasmodium parasite was documented in a Northern Spotted Owl for the first time. West Coast Barred Owls had a lower prevalence of infection (15%) when compared to sympatric Spotted Owls (S. o. caurina 52%, S. o. occidentalis 79%) and Barred Owls from the historic range (61%). Consequently, Barred Owls on the West Coast may have a competitive advantage over the potentially immune compromised Spotted Owls. ?? 2008 Ishak et al.

Publication Year 2008
Title Blood parasites in Owls with conservation implications for the Spotted Owl (Strix occidentalis)
DOI 10.1371/journal.pone.0002304
Authors H.D. Ishak, J.P. Dumbacher, N.L. Anderson, J.J. Keane, G. Valkiunas, S. M. Haig, L.A. Tell, R.N.M. Sehgal
Publication Type Article
Publication Subtype Journal Article
Series Title PLoS ONE
Index ID 70000516
Record Source USGS Publications Warehouse
USGS Organization Forest and Rangeland Ecosystem Science Center