Volume 10, Number 12—December 2004
Research
West Nile Virus Outbreak in North American Owls, Ontario, 2002
Table 1
Deaths at the Owl Foundation property during a WNV outbreak (July 26–September 28, 2002) and results of real-time RT-PCR on tissues from dead birdsa
Species | At risk | Died | Tested | Positive n (%) | Crude DR % | WNV-related DR % |
---|---|---|---|---|---|---|
Snowy Owl (Bubo scandiacus) | 20 | 20 | 11 | 11 (100) | 100 | 100 |
Northern Hawk Owl (Surnia ulula) | 26 | 26 | 17 | 17 (100) | 100 | 100 |
Great Gray Owl (Strix nebulosa) | 27 | 27 | 23 | 21 (91.3) | 100 | 91.3 |
Boreal Owl (Aegolius funereus) | 11 | 11 | 11 | 10 (90.9) | 100 | 90.9 |
Northern Saw-whet Owl (Ae. acadicus) | 13 | 12 | 12 | 12 (100) | 92.3 | 92.3 |
Northern Pygmy Owl (Glaucidium gnoma) | 6 | 1 | 1 | 1 (100) | 16.7 | 16.7 |
Short-eared Owl (Asio flammeus) | 16 | 2 | 2 | 2 (100) | 12.5 | 12.5 |
Flammulated Owl (Otus flammeolus) | 9 | 1 | 1 | 1 (100) | 11.1 | 11.1 |
Long-eared Owl (A. otus) | 13 | 3 | 3 | 1 (33.3) | 23.1 | 7.7 |
Great Horned Owl (B. virginianus) | 22 | 2 | 1 | 1 (100) | 9.1 | 4.5 |
Barn Owl (Tyto alba) | 10 | 0 | 0 | – | 0 | 0 |
Barred Owl (S. varia) | 8 | 1 | 1 | 0 (0) | 12.5 | 0 |
Burrowing Owl (Athene cunicularia) | 10 | 0 | 0 | – | 0 | 0 |
Eastern Screech Owl (Megascops asio) | 36 | 0 | 0 | – | 0 | 0 |
Elf Owl (Micrathene whitneyi) | 1 | 0 | 0 | – | – | – |
Spotted Owl (S. oocidentalis) | 1 | 1 | 1 | 1 (100) | – | – |
Tawny Owl (S. aluco) | 2 | 1 | 1 | 1 (100) | – | – |
American Kestrel (Falco sparverius) | 2 | 0 | 0 | – | – | – |
Peregrine Falcon (F. peregrinus) | 2 | 0 | 0 | – | – | – |
Total | 235 | 108 | 85 | 79 (92.9) | 46 | 43 |
aWNV, West Nile virus; RT-PCR, reverse transcription–polymerase chain reaction; DR, death rate (calculated when n > 6).