| Little is known about the Northern Saw-whet Owl's distribution, or migratory behaviour within the prairie provinces. I examined saw-whet migration and population trends using the migration monitoring data collected by the Delta Marsh Bird Observatory (DMBO), Manitoba (2000--2007). Multiple regression suggested that populations were stable, however, the analysis had low power to detect trends. Correlation between saw-whet data from DMBO and the Manitoba Nocturnal Owl Survey suggested that population fluctuations were synchronized over large regions. Correlations between saw-whet owl and small mammal abundance from southeastern Manitoba suggested that saw-whet density and reproductive success were influenced by cycles of mammal abundance, which also synchronized over large regions. Finally, I used hydrogen isotope analysis on owl feathers to identify the latitudinal origins of saw-whet owls migrating through Delta Marsh. However, adult feathers showed large deuterium enrichment patterns, indicating that this technique cannot be used to track adult owl movements without further refinement. |
