A significant surge of migrating owls has kept researchers at the Mugaha Marsh Banding Station busy as the birds travel through northern British Columbia in unprecedented numbers. Jeannine Randall, a bird biologist at the Mackenzie Nature Observatory, located around 200 kilometers north of Prince George, described this year as exceptional. Typically catching around 100 owls, they have already caught 266 this season with two weeks still remaining, marking a record-breaking year.
The sudden increase in owl numbers posed a unique challenge as there was a shortage of the specific tracking bands required to monitor the birds. Randall explained that they faced a scarcity of the larger band size, crucial for saw-whet owls, their primary target species, due to delays in receiving the bands from the bird banding office.
While seeking assistance from other organizations, it became evident that the surge in owl populations was widespread, leading to similar shortages at various stations. Randall attributes the spike in numbers to the abundance of small rodents this year, which serve as the main prey for these owls, including mice, deer mice, and voles.
Despite the positive numbers at Mackenzie, Rémi Torrenta from Birds Canada highlighted a concerning trend of declining owl populations over the past 25 years. While some species like barred owls show stability or growth, most owl species, including the northern saw-whet owls in British Columbia, have been on the decline.
Torrenta explained that the current high owl volume is likely part of a documented four-year cycle, where an overflow of owls leads to a subsequent crash in rodent populations the following year, forcing the owls to migrate southward in search of food, known as a mass eruption. To monitor these patterns, Birds Canada oversees the Nocturnal Owl Survey, a citizen science initiative that relies on volunteers nationwide to track owl populations each spring.
The banding project at the Mackenzie Nature Observatory plays a vital role in this research, offering essential data on owl populations and migration routes. Recently, the station recaptured an owl banded in Victoria in 2024, shedding light on the species’ travel behaviors. Randall emphasized the importance of such studies in making informed conservation decisions and enhancing species understanding.