Long-eared Owls, Asio otus: A Review of North American Banding
In Saskatchewan, at the northern edge of the species’ range, the Long-eared Owl (Asio otus) is an irruptive species that has appeared in numbers during major vole (Microtus) outbreaks in 4 of 44 years. Seven other years have had either no bandings or no sightings over large areas. In a search for po...
| Published in: | The Canadian Field-Naturalist |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
The Ottawa Field-Naturalists' Club
2005
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| Subjects: | |
| Online Access: | https://www.canadianfieldnaturalist.ca/index.php/cfn/article/view/151 https://doi.org/10.22621/cfn.v119i3.151 |
| Summary: | In Saskatchewan, at the northern edge of the species’ range, the Long-eared Owl (Asio otus) is an irruptive species that has appeared in numbers during major vole (Microtus) outbreaks in 4 of 44 years. Seven other years have had either no bandings or no sightings over large areas. In a search for possible evidence of food-based nomadism, population trends, length and synchronicity of cycles, and longevity, I reviewed all banding in North America through 1998. Prior to banding office computerization (retroactive to 1955), 803 Long-eared Owls had been banded with 33 band encounters (4.1%). Between 1955 and 1998 there were another 10,250 banded by 426 banders with 86 band encounters (0.8%). Encounter records, especially those involving unexpected directions and distances, tend to support but do not prove food-based nomadism. Peaks of migration movements at different long-term stations occurred in different years. There is soft evidence of both 10- and 3-yr cycles. There is inconclusive evidence for a continuing population decline. The oldest banded bird in North America lived for 11 years, 1 month, but another possibly lived for 15 years, 8 months. |
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